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1

A Coupled Model for Natural Convection and Condensation in Heated Subsurface Enclosures Embedded in Fractured Rock  

E-Print Network (OSTI)

and Mass Transfer in Yucca Mountain Drifts,” Proceedings ofMD- 000001 REV 00, Yucca Mountain Project Report, Bechtelthe fractured rock at Yucca Mountain have been investigated

Halecky, N.; Birkholzer, J.T.; Webb, S.W.; Peterson, P.F.; Bodvarsson, G.S.

2006-01-01T23:59:59.000Z

2

Crustal Rock Fracture Mechanics for Design and Control of Artificial Subsurface Cracks in Geothermal Energy Extraction Engineering ({Gamma}-Project)  

DOE Green Energy (OSTI)

Recently a significant role of artificial and/or natural cracks in the geothermal reservoir has been demonstrated in the literatures (Abe, H., et al., 1983, Nielson, D.L. and Hullen, J.B., 1983), where the cracks behave as fluid paths and/or heat exchanging surfaces. Until now, however, there are several problems such as a design procedure of hydraulic fracturing, and a quantitative estimate of fluid and heat transfer for reservoir design. In order to develop a design methodology of geothermal reservoir cracks, a special distinguished research project, named as ''{Lambda}-Project'', started at Tohoku University (5 years project, 1983-1988). In this project a basic fracture mechanics model of geothermal reservoir cracks is being demonstrated and its validation is being discussed both theoretically and experimentally. This paper descibes an outline of ''{Lambda}-Project''.

Abe, Hiroyuki; Takahashi, Hideaki

1983-12-15T23:59:59.000Z

3

Relative Permeability of Fractured Rock  

DOE Green Energy (OSTI)

Contemporary understanding of multiphase flow through fractures is limited. Different studies using synthetic fractures and various fluids have yielded different relative permeability-saturation relations. This study aimed to extend the understanding of multiphase flow by conducting nitrogen-water relative permeability experiments on a naturally-fractured rock from The Geysers geothermal field. The steady-state approach was used. However, steady state was achieved only at the endpoint saturations. Several difficulties were encountered that are attributed to phase interference and changes in fracture aperture and surface roughness, along with fracture propagation/initiation. Absolute permeabilities were determined using nitrogen and water. The permeability values obtained change with the number of load cycles. Determining the absolute permeability of a core is especially important in a fractured rock. The rock may change as asperities are destroyed and fractures propagate or st rain harden as the net stresses vary. Pressure spikes occurred in water a solute permeability experiments. Conceptual models of an elastic fracture network can explain the pressure spike behavior. At the endpoint saturations the water relative permeabilities obtained are much less than the nitrogen gas relative permeabilities. Saturations were determined by weighing and by resistivity calculations. The resistivity-saturation relationship developed for the core gave saturation values that differ by 5% from the value determined by weighing. Further work is required to complete the relative permeability curve. The steady-state experimental approach encountered difficulties due to phase interference and fracture change. Steady state may not be reached until an impractical length of time. Thus, unsteady-state methods should be pursued. In unsteady-state experiments the challenge will be in quantifying rock fracture change in addition to fluid flow changes.

Mark D. Habana

2002-06-30T23:59:59.000Z

4

Evaluation of subsurface fracture geometry using fluid pressure response to  

Open Energy Info (EERE)

subsurface fracture geometry using fluid pressure response to subsurface fracture geometry using fluid pressure response to solid earth tidal strain Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: Evaluation of subsurface fracture geometry using fluid pressure response to solid earth tidal strain Details Activities (1) Areas (1) Regions (0) Abstract: The nature of solid earth tidal strain and surface load deformation due to the influence of gravitational forces and barometric pressure loading are discussed. The pore pressure response to these types of deformation is investigated in detail, including the cases of a confined aquifer intersected by a well and a discrete fracture intersected by a well. The integration of the tidal response method with conventional pump tests in order to independently calculate the hydraulic parameters of the

5

Characterization of subsurface fracture patterns in the Coso geothermal  

Open Energy Info (EERE)

subsurface fracture patterns in the Coso geothermal subsurface fracture patterns in the Coso geothermal reservoir by analyzing shear-wave splitting of microearthquake seismorgrams Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: Characterization of subsurface fracture patterns in the Coso geothermal reservoir by analyzing shear-wave splitting of microearthquake seismorgrams Details Activities (1) Areas (1) Regions (0) Abstract: A large number of microearthquake seismograms have been recorded by a downhole, three-component seismic network deployed around the Coso, California geothermal reservoir. Shear-wave splitting induced by the alignment of cracks in the reservoir has been widely observed in the recordings. Over 100 events with body wave magnitude greater than 1.0 from

6

Proceedings of the International Symposium on Dynamics of Fluids in Fractured Rocks: Concepts and Recent Advances  

DOE Green Energy (OSTI)

This publication contains extended abstracts of papers presented at the International Symposium ''Dynamics of Fluids in Fractured Rocks: Concepts and Recent Advances'' held at Ernest Orlando Lawrence Berkeley National Laboratory on February 10-12, 1999. This Symposium is organized in Honor of the 80th Birthday of Paul A. Witherspoon, who initiated some of the early investigations on flow and transport in fractured rocks at the University of California, Berkeley, and at Lawrence Berkeley National Laboratory. He is a key figure in the development of basic concepts, modeling, and field measurements of fluid flow and contaminant transport in fractured rock systems. The technical problems of assessing fluid flow, radionuclide transport, site characterization, modeling, and performance assessment in fractured rocks remain the most challenging aspects of subsurface flow and transport investigations. An understanding of these important aspects of hydrogeology is needed to assess disposal of nu clear wastes, development of geothermal resources, production of oil and gas resources, and remediation of contaminated sites. These Proceedings of more than 100 papers from 12 countries discuss recent scientific and practical developments and the status of our understanding of fluid flow and radionuclide transport in fractured rocks. The main topics of the papers are: Theoretical studies of fluid flow in fractured rocks; Multi-phase flow and reactive chemical transport in fractured rocks; Fracture/matrix interactions; Hydrogeological and transport testing; Fracture flow models; Vadose zone studies; Isotopic studies of flow in fractured systems; Fractures in geothermal systems; Remediation and colloid transport in fractured systems; and Nuclear waste disposal in fractured rocks.

Faybishenko, B. (ed.)

1999-02-01T23:59:59.000Z

7

Proceedings of the International Symposium on Dynamics of Fluids in Fractured Rocks: Concepts and Recent Advances  

SciTech Connect

This publication contains extended abstracts of papers presented at the International Symposium ''Dynamics of Fluids in Fractured Rocks: Concepts and Recent Advances'' held at Ernest Orlando Lawrence Berkeley National Laboratory on February 10-12, 1999. This Symposium is organized in Honor of the 80th Birthday of Paul A. Witherspoon, who initiated some of the early investigations on flow and transport in fractured rocks at the University of California, Berkeley, and at Lawrence Berkeley National Laboratory. He is a key figure in the development of basic concepts, modeling, and field measurements of fluid flow and contaminant transport in fractured rock systems. The technical problems of assessing fluid flow, radionuclide transport, site characterization, modeling, and performance assessment in fractured rocks remain the most challenging aspects of subsurface flow and transport investigations. An understanding of these important aspects of hydrogeology is needed to assess disposal of nu clear wastes, development of geothermal resources, production of oil and gas resources, and remediation of contaminated sites. These Proceedings of more than 100 papers from 12 countries discuss recent scientific and practical developments and the status of our understanding of fluid flow and radionuclide transport in fractured rocks. The main topics of the papers are: Theoretical studies of fluid flow in fractured rocks; Multi-phase flow and reactive chemical transport in fractured rocks; Fracture/matrix interactions; Hydrogeological and transport testing; Fracture flow models; Vadose zone studies; Isotopic studies of flow in fractured systems; Fractures in geothermal systems; Remediation and colloid transport in fractured systems; and Nuclear waste disposal in fractured rocks.

Faybishenko, B. (ed.)

1999-02-01T23:59:59.000Z

8

Proceedings of the Second International Symposium on Dynamics of Fluids in Fractured Rock  

E-Print Network (OSTI)

toward the heat source, or into the rock underlying the heatcharacterizing DNAPL source zones in fractured rock at theby a point source injection in fractured rock with multiple

Faybishenko, Boris; Witherspoon, Paul A.

2004-01-01T23:59:59.000Z

9

Subsurface fracture mapping from geothermal wellbores. Final report  

DOE Green Energy (OSTI)

To advance the state-of-the-art in Hot Dry Rock technology, and evaluation is made of (1) the use of both electromagnetic and acoustic radar to map far-field fractures, (2) the use of more than twenty different conventional well logging tools to map borehole-fracture intercepts, (3) the use of magnetic dipole ranging to determine the relative positions of the injection well and the production well within the fractured zone, (4) the use of passive microseismic methods to determine the orientation and extent of hydraulic fractures, and (5) the application of signal processing techniques to fracture mapping including tomography, holography, synthetic aperture, image reconstruction, and the relative importance of phase and amplitude information. It is found that according to calculations, VHF backscatter radar has the potential for mapping fractures within a distance of 50 +- 20 meters from the wellbore. A new technique for improving fracture identification is presented. The range of acoustic radar is five to seven times greater than that of VHF radar when compared on the basis of equal resolution, i.e., equal wavelengths. Analyses of extant data indicate that when used synergistically the (1) caliper, (2) resistivity dipmeter, (3) televiewer, (4) television, (5) impression packer, and (6) acoustic transmission are useful for mapping borehole-fracture intercepts. A new model of hydraulic fracturing is presented which indicates that a hydraulic fracture is dynamically unstable; consequently, improvements in locating the crack tip may be possible. The importance of phase in signal processing is stressed and those techniques which employ phase data are emphasized for field use.

Hartenbaum, B.A.; Rawson, G.

1983-08-01T23:59:59.000Z

10

Permeability Estimation From Velocity Anisotropy In Fractured Rock  

E-Print Network (OSTI)

Cracks in a rock mass subjected to a uniaxial stress will be preferentially closed depending on the angle between the fracture normal vectors and the direction of the applied stress. If the prestress fracture orientation ...

Gibson, Richard L., Jr.

1990-01-01T23:59:59.000Z

11

Seepage into drifts in unsaturated fractured rock at Yucca Mountain  

E-Print Network (OSTI)

Fractured Rock at Yucca Mountain Jens Birkholzer, Guomin Lrepository site at Yucca Mountain, Nevada, as it is locatedclimate conditions at Yucca Mountain. The numerical study is

Birkholzer, Jens; Li, Guomin; Tsang, Chin-Fu; Tsang, Yvonne

1998-01-01T23:59:59.000Z

12

Deriving the shape factor of a fractured rock matrix  

SciTech Connect

Fluid flow from a fractured rock matrix was investigated for accurately predicting oil recovery from fractured reservoirs. To relate the oil rate with rock geometry and average rock matrix pressure, a shape factor is used in the mathematical model of fractured reservoirs. The shape factor in the transfer function was derived by solving the three-dimensional diffusivity equation of a rock matrix block under unsteady-state production, in contrast to the quasi-steady-state condition assumed by most previous studies denoted in the literature. The diffusivity equation in the x, y, and z coordinate was solved in four cases by assuming different boundary conditions of (1) constant fracture pressure; (2) constant flow rate; (3) constant fracture pressure followed by linearly declining fracture pressure; and (4) linearly declining fracture pressure followed by constant fracture pressure. Shape factor values are high at the initial depletion stage under an unsteady-state condition. When the fracture pressure is constant, the shape factor converges to {pi}{sup 2}/L{sup 2}, 2{pi}{sup 2}/L{sup 2}, and 3{pi}{sup 2}/L{sup 2} for one-, two-, and three-dimensional rock matrix, respectively, at the dimensionless time ({tau}) of about 0.1. When the flow rate between the rock matrix and the fracture is constant, the fracture pressure varies with location on the rock surface. Based on the average fracture pressure, the shape factor decreases with production time until a {tau} value of 0.1 is reached. The boundary conditions of constant fracture pressure followed by a constant decline in fracture pressure are equivalent to the condition of a constant fracture pressure followed by a period of constant flow rate.

Chang, Ming-Ming

1993-09-01T23:59:59.000Z

13

Distribution and geochemistry of contaminated subsurface waters in fissured volcanogenic bed rocks of the Lake Karachai Area, Chelyabinsk, Southern Urals  

Science Conference Proceedings (OSTI)

The present investigation is devoted to the study of the distribution and geochemistry of contaminated subsurface waters, beneath the site of temporary storage of liquid radioactive waste known as Lake Karachai. For this purpose a method of hydrogeochemical logging (HGCL) together with standard hydrogeochemical and geophysical methods of uncased hole logging were used. The distribution of sodium nitrate brine plumes in the subsurface was determined by the physical and physico-chemical properties of these brines and by the petrochemical composition of enclosing rocks and the structural setting of the flow paths. The latter is represented by fractures and large faults in the bedrock of volcanogenic and volcanogenic-sedimentary rocks of intermediate-to-basic composition. The volcanogenic rocks are overlain in some places by a thin cover of unconsolidated sediments, i.e., by loams and relatively impermeable silts. Contaminated waters flow-in accordance with the eluvium bottom relief towards local areas of natural (Mishelyak and Techa rivers) and artificial (Novogomenskii water intake) discharge of subsurface waters. The large Mishelyak fault, southwest of Lake Karachai and under fluvial sediments of the Mishelyak, is assumed to significantly influence the flow pattern of contaminated waters, diverting them from an intake of drinking water.

Solodov, I.N.; Belichkin, V.I.; Zotov, A.V.; Kochkin, B.T. [Russian Academy of Sciences, Moscow (Russian Federation); Drozhko, E.G. [Atomic Energy of Russia (Russian Federation); Glagolev, A.V.; Skokov, A.N. [Russian Federation Committee on Geological and Subsurface Usage (Russian Federation)

1994-06-01T23:59:59.000Z

14

Microwave assisted hard rock cutting  

DOE Patents (OSTI)

An apparatus for the sequential fracturing and cutting of subsurface volume of hard rock (102) in the strata (101) of a mining environment (100) by subjecting the volume of rock to a beam (25) of microwave energy to fracture the subsurface volume of rock by differential expansion; and , then bringing the cutting edge (52) of a piece of conventional mining machinery (50) into contact with the fractured rock (102).

Lindroth, David P. (Apple Valley, MN); Morrell, Roger J. (Bloomington, MN); Blair, James R. (Inver Grove Heights, MN)

1991-01-01T23:59:59.000Z

15

Modeling rock fracturing in bench-blasting problems  

SciTech Connect

A computational model of rock blasting is being developed to examine the blasting problems associated with in situ oil shale processing. This model, however, will also be useful as a design tool for the traditional problems in rock blasting. The model includes fundamental treatment of both shock-wave propagation and the accumulation of brittle fracture in the rock. As a result, the model accurately predicts the degree and extent of fracturing as functions of design parameters. The model has proven useful for making parametric studies and for evaluation of alternate blast designs. This paper demonstrates the use of the numerical model to simulate the fracturing induced by the detonation of a vertical explosive column near a bench. The fracturing induced by three different explosives indicate that (in the chosen geometry) the most efficient breakage is done by a column of ammonium nitrate and fuel oil mixture (ANFO) used with a toe charge of aluminized ANFO. There was too much unfractured rock left when ANFO was used alone; aluminized ANFO used for the entire explosive column caused excessive fracturing. A final case involves ANFO used alone to fracture a different rock type. This case points out that in a different rock type, the ANFO will not leave excessive unfractured rock.

Kuszmaul, J.S.

1987-01-01T23:59:59.000Z

16

Analytic solutions of tracer transport in fractured rock associated with precipitation-dissolution reactions  

DOE Green Energy (OSTI)

Precipitation-dissolution reactions are important for a number of applications such as isotopic tracer transport in the subsurface. Analytical solutions have been developed for tracer transport in both single-fracture and multiple-fracture systems associated with these reactions under transient and steady-state transport conditions. These solutions also take into account advective transport in fractures and molecular diffusion in the rock matrix. For studying distributions of disturbed tracer concentration (the difference between actual concentration and its equilibrium value), effects of precipitation-dissolution reactions are mathematically equivalent to a 'decay' process with a decay constant proportional to the corresponding bulk reaction rate. This important feature significantly simplifies the derivation procedure by taking advantage of the existence of analytical solutions for tracer transport associated with radioactive decay in fractured rock. It is also useful for interpreting tracer breakthrough curves, because the impact of a decay process is relatively easy to analyze. Several illustrative examples are presented, which show that the results are sensitive to fracture spacing, matrix diffusion coefficient (fracture surface area), and bulk reaction rate (or 'decay' constant), indicating that the relevant flow and transport parameters may be estimated by analyzing tracer signals.

Liu, H.H.; Mukhopadhyay, S.; Spycher, N.; Kennedy, B.

2011-03-15T23:59:59.000Z

17

Anomalous fracture-extension pressure in granitic rocks  

DOE Green Energy (OSTI)

Fracture-extension pressures appreciably higher than the least principal earth-stress were observed in hydraulic fractures formed in a pair of 3 km (9600 ft) deep boreholes drilled near the Valles Caldera in northern New Mexico. Pressurization of open wellbores in rock containing preexisting fractures may open these fractures, instead of creating new fractures at right angles to the least principal stress. The pressure necessary to flow into these fractures may be appreciably higher than the least principal stress. Upon sand-propping one such pre-existing fracture, a lower fracture extension pressure was observed. A second fracture in a parallel well-bore 92 m (300 ft) away, at the same depth of 2 km (6500 ft) exhibited the lower fracture extension pressure without propping, but with about 90/sup 0/ difference in fracture direction. Fractures created through perforations at a depth of 3 km (9600 ft) not only exhibited breakdown pressures upon initial pressurization, but sometimes even higher ''breakdown'' pressures upon repressurization. These phenomena may be of interest in the interpretation of earth stress measurements made by hydraulic fracturing.

Aamodt, R.L.; Potter, R.M.

1978-01-01T23:59:59.000Z

18

A Study of Hydraulic Fracturing Initiation in Transversely Isotropic Rocks  

E-Print Network (OSTI)

Hydraulic fracturing of transverse isotropic reservoirs is of major interest for reservoir stimulation and in-situ stress estimation. Rock fabric anisotropy not only causes in-situ stress anisotropy, but also affects fracture initiation from the wellbore. In this study a semi-analytical method is used to investigate these effects with particular reference to shale stimulation. Using simplifying assumptions, equations are derived for stress distribution around the wellbore's walls. The model is then used to study the fracture initiation pressure variations with anisotropy. A sensitivity analysis is carried out on the impact of Young's modulus and Poisson's ration, on the fracture initiation pressure. The results are useful in designing hydraulic fractures and also can be used to develop information about in-situ rock properties using failure pressure values observed in the field. Finally, mechanical and permeability anisotropy are measured using Pulse Permeameter and triaxial tests on Pierre shale.

Serajian, Vahid

2011-08-01T23:59:59.000Z

19

Fracture network modeling of a Hot Dry Rock geothermal reservoir  

DOE Green Energy (OSTI)

Fluid flow and tracer transport in a fractured Hot Dry Rock (HDR) geothermal reservoir are modeled using fracture network modeling techniques. The steady state pressure and flow fields are solved for a two-dimensional, interconnected network of fractures with no-flow outer boundaries and constant-pressure source and sink points to simulate wellbore-fracture intersections. The tracer response is simulated by particle tracking, which follows the progress of a representative sample of individual tracer molecules traveling through the network. Solute retardation due to matrix diffusion and sorption is handled easily with these particle tracking methods. Matrix diffusion is shown to have an important effect in many fractured geothermal reservoirs, including those in crystalline formations of relatively low matrix porosity. Pressure drop and tracer behavior are matched for a fractured HDR reservoir tested at Fenton Hill, NM.

Robinson, B.A.

1988-01-01T23:59:59.000Z

20

Ozone generation by rock fracture: Earthquake early warning?  

Science Conference Proceedings (OSTI)

We report the production of up to 10 ppm ozone during crushing and grinding of typical terrestrial crust rocks in air, O{sub 2} and CO{sub 2} at atmospheric pressure, but not in helium or nitrogen. Ozone is formed by exoelectrons emitted by high electric fields, resulting from charge separation during fracture. The results suggest that ground level ozone produced by rock fracture, besides its potential health hazard, can be used for early warning in earthquakes and other catastrophes, such as landslides or land shifts in excavation tunnels and underground mines.

Baragiola, Raul A.; Dukes, Catherine A.; Hedges, Dawn [Engineering Physics, University of Virginia, Charlottesville, Virginia 22904 (United States)

2011-11-14T23:59:59.000Z

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Neutron Production from the Fracture of Piezoelectric Rocks  

E-Print Network (OSTI)

A theoretical explanation is provided for the experimental evidence that fracturing piezoelectric rocks produces neutrons. The elastic energy micro-crack production ultimately yields the macroscopic fracture. The mechanical energy is converted by the piezoelectric effect into electric field energy. The electric field energy decays via radio frequency (microwave) electric field oscillations. The radio frequency electric fields accelerate the condensed matter electrons which then collide with protons producing neutrons and neutrinos.

A. Widom; J. Swain; Y. N. Srivastava

2011-09-22T23:59:59.000Z

22

Neutron Production from the Fracture of Piezoelectric Rocks  

E-Print Network (OSTI)

A theoretical explanation is provided for the experimental evidence that fracturing piezoelectric rocks produces neutrons. The elastic energy micro-crack production ultimately yields the macroscopic fracture. The mechanical energy is converted by the piezoelectric effect into electric field energy. The electric field energy decays via radio frequency (microwave) electric field oscillations. The radio frequency electric fields accelerate the condensed matter electrons which then collide with protons producing neutrons and neutrinos.

Widom, A; Srivastava, Y N

2011-01-01T23:59:59.000Z

23

Evaluation of subsurface fracture geometry using fluid pressure...  

Open Energy Info (EERE)

response method with conventional pump tests in order to independently calculate the hydraulic parameters of the fracture-formation system is discussed. How advanced spectral...

24

Flow dynamics and solute transport in unsaturated rock fractures  

DOE Green Energy (OSTI)

Rock fractures play an important role in flow and contaminant transport in fractured aquifers, production of oil from petroleum reservoirs, and steam generation from geothermal reservoirs. In this dissertation, phenomenological aspects of flow in unsaturated fractures were studied in visualization experiments conducted on a transparent replica of a natural, rough-walled rock fracture for inlet conditions of constant pressure and flow rate over a range of angles of inclination. The experiments demonstrated that infiltrating liquid proceeds through unsaturated rock fractures along non-uniform, localized preferential flow paths. Even in the presence of constant boundary conditions, intermittent flow was a persistent flow feature observed, where portions of the flow channel underwent cycles of snapping and reforming. Two modes of intermittent flow were observed, the pulsating blob mode and the rivulet snapping mode. A conceptual model for the rivulet snapping mode was proposed and examined using idealized, variable-aperture fractures. The frequency of intermittent flow events was measured in several experiments and related to the capillary and Bond numbers to characterize this flow behavior.

Su, G. W.

1999-10-01T23:59:59.000Z

25

An Analytical Model for Solute Transport in Unsaturated Flow through a Single Fracture and Porous Rock Matrix  

E-Print Network (OSTI)

fracture – matrix solute source rock matrix rock matrix vin fracture; b) solute source in rock matrix. Draft 8-11-04for a point source in the rock matrix are presented in

Houseworth, J.E.

2004-01-01T23:59:59.000Z

26

THERMO-HYDRO-MECHANICAL MODELING OF WORKING FLUID INJECTION AND THERMAL ENERGY EXTRACTION IN EGS FRACTURES AND ROCK MATRIX  

DOE Green Energy (OSTI)

Development of enhanced geothermal systems (EGS) will require creation of a reservoir of sufficient volume to enable commercial-scale heat transfer from the reservoir rocks to the working fluid. A key assumption associated with reservoir creation/stimulation is that sufficient rock volumes can be hydraulically fractured via both tensile and shear failure, and more importantly by reactivation of naturally existing fractures (by shearing), to create the reservoir. The advancement of EGS greatly depends on our understanding of the dynamics of the intimately coupled rock-fracture-fluid-heat system and our ability to reliably predict how reservoirs behave under stimulation and production. Reliable performance predictions of EGS reservoirs require accurate and robust modeling for strongly coupled thermal-hydrological-mechanical (THM) processes. Conventionally, these types of problems have been solved using operator-splitting methods, usually by coupling a subsurface flow and heat transport simulators with a solid mechanics simulator via input files. An alternative approach is to solve the system of nonlinear partial differential equations that govern multiphase fluid flow, heat transport, and rock mechanics simultaneously, using a fully coupled, fully implicit solution procedure, in which all solution variables (pressure, enthalpy, and rock displacement fields) are solved simultaneously. This paper describes numerical simulations used to investigate the poro- and thermal- elastic effects of working fluid injection and thermal energy extraction on the properties of the fractures and rock matrix of a hypothetical EGS reservoir, using a novel simulation software FALCON (Podgorney et al., 2011), a finite element based simulator solving fully coupled multiphase fluid flow, heat transport, rock deformation, and fracturing using a global implicit approach. Investigations are also conducted on how these poro- and thermal-elastic effects are related to fracture permeability evolution.

Robert Podgorney; Chuan Lu; Hai Huang

2012-01-01T23:59:59.000Z

27

Micro-crack Damage Evolution of Fracturing Rock Chaotic Characteristics  

Science Conference Proceedings (OSTI)

Chaotic theory and bifurcation of modern nonlinear science were used to study the evolution of micro-cracks under the hydraulic fracturing of the rock mass characteristics, the tensor damage variable which described the chao evolution of micro-cracks ... Keywords: chaos theory, bifurcation theory, damage evolution

Zhaowan Chun; Wang Tingting

2010-06-01T23:59:59.000Z

28

Validation studies for assessing unsaturated flow and transport through fractured rock  

SciTech Connect

*The objectives of this contract are to examine hypotheses and conceptual models concerning unsaturated flow and transport through heterogeneous fractured rock and to design and execute confirmatory field and laboratory experiments to test these hypotheses and conceptual models. Important new information is presented such as the application and evaluation of procedures for estimating hydraulic, pneumatic, and solute transport coefficients for a range of thermal regimes. A field heater experiment was designed that focused on identifying the suitability of existing monitoring equipment to obtain required data. A reliable method was developed for conducting and interpreting tests for air permeability using a straddle-packer arrangement. Detailed studies of fracture flow from Queen Creek into the Magina Copper Company ore haulage tunnel have been initiated. These studies will provide data on travel time for transport of water and solute in unsaturated tuff. The collection of rainfall runoff, and infiltration data at two small watersheds at the Apache Leap Tuff Site enabled us to evaluate the quantity and rate of water infiltrating into the subsurface via either fractures or matrix. Characterization methods for hydraulic parameters relevant to Weigh-level waste transport, including fracture apertures, transmissivity, matrix porosity, and fracture wetting front propagation velocities, were developed.

Bassett, R.L.; Neuman, S.P.; Rasmussen, T.C.; Guzman, A.; Davidson, G.R.; Lohrstorfer, C.F. [Arizona Univ., Tucson, AZ (United States). Dept. of Hydrology and Water Resources

1994-08-01T23:59:59.000Z

29

Colloid-facilitated radionuclide transport in fractured porous rock  

E-Print Network (OSTI)

Numerical methods have been applied for the prediction of colloid-facilitated radionuclide transport through water-saturated fractured porous rock. The presence of colloids may enhance the transport of radionuclides in groundwater by reducing retardation effects. The colloids existing in the groundwater act as carriers, adsorbing radionuclides on their large surface area and moving faster than the average water velocity. With colloids present, the system consists of three phases, i. e., an aqueous phase, a carrier phase, and a stationary solid phase. In the basic model, one-dimensional advection in a single planar fracture of infinite extent is coupled with diffusion in the rock matrix perpendicular to the fracture. In this study, a full-equilibrium model was developed to describe the transport and fate of the radionuclides in the fracture. Sorption onto rock matrix, fracture surface and sorption into mobile and immobile colloids are included. The effect of colloidal particle size was also considered. Mass partition mechanisms between the colloids and solid matrix and between colloid and contaminant are represented by local equilibrium. In the three-phase i.e., retardation coefficient, hydrodynamic dispersion system, the coefficient, and fracture width are modified to include the equilibrium distribution coefficient of contaminant with a carrier. In the three phase model, much smaller retardation and hydrodynamic dispersion coefficients are obtained and the effect of fracture width is larger. With the additional consideration of colloidal particle sizes, these effects become ever larger. Numerical solutions for the model were obtained using a fully implicit finite difference scheme. A significant sensitivity to model parameters was discovered, and in particular, the equilibrium distribution coefficients between a contaminant and the carrier were found to be the most important factors.

Baek, Inseok

1994-01-01T23:59:59.000Z

30

Hot dry rock fracture propagation and reservoir characterization  

DOE Green Energy (OSTI)

North America's largest hydraulic fracturing opeations have been conducted at Fenton hill, New mexico to creae hot dry rock geothermal reservoirs. Microearthquakes induced by these fracturing operations were measured with geophones. The large volume of rock over which the microearthquakes were distributed indicates a mechanism of hydraulic stimulation which is at odds with conventional fracturing theory, which predicts failure along a plane which is perpendicular to the least compressive earth stress. Shear slippage along pre-existing joints in the rock is more easily induced than conventional tensile failure, particularly when the difference between minimum and maximum earth stresses is large and the pre-existing joints are oriented at angles between 30 and 60)degree) to the principal earth stresses, and a low viscosity fluid like water is injected. Shear slippage results in local redistribution of stresses, which allows a branching, or dendritic, stimulation pattern to evolve, in agreement with the patterns of microearthquake locations. Field testing of HDR reservoirs at the Fenton Hill site shows that significant reservoir growth occurred as energy was extracted. Tracer, microseismic, and geochemical measurements provided the primary quantitative evidence for the increases in accessible reservoir volume and fractured rock surface area. These temporal increases indicate that augmentation of reservoir heat production capacity in hot dry rock system occurred. For future reservoir testing, Los Alamos is developing tracer techniques using reactive chemicals to track thermal fronts. Recent studies have focused on the kinetics of hydrolysis of derivatives of bromobenzene, which can be used in reservoirs as hot as 275)degree)C.

Murphy, H.; Fehler, M.; Robinson, B.; Tester, J.; Potter, R.; Birdsell, S.

1988-01-01T23:59:59.000Z

31

On Water Flow in Hot Fractured Rock -- A Sensitivity Study on the Impact of Fracture-Matrix Heat Transfer  

E-Print Network (OSTI)

for both liquid and heat transfer processes. In order to beprocesses in hot fractured rock with ( 1) flow channeling in fractures, (2) interface reduction in F-M heat transfer,

Birkholzer, Jens T.; Zhang, Yingqi

2005-01-01T23:59:59.000Z

32

Fracture and Healing of Rock Salt Related to Salt Caverns  

Science Conference Proceedings (OSTI)

In recent years, serious investigations of potential extension of the useful life of older caverns or of the use of abandoned caverns for waste disposal have been of interest to the technical community. All of the potential applications depend upon understanding the reamer in which older caverns and sealing systems can fail. Such an understanding will require a more detailed knowledge of the fracture of salt than has been necessary to date. Fortunately, the knowledge of the fracture and healing of salt has made significant advances in the last decade, and is in a position to yield meaningful insights to older cavern behavior. In particular, micromechanical mechanisms of fracture and the concept of a fracture mechanism map have been essential guides, as has the utilization of continuum damage mechanics. The Multimechanism Deformation Coupled Fracture (MDCF) model, which is summarized extensively in this work was developed specifically to treat both the creep and fracture of salt, and was later extended to incorporate the fracture healing process known to occur in rock salt. Fracture in salt is based on the formation and evolution of microfractures, which may take the form of wing tip cracks, either in the body or the boundary of the grain. This type of crack deforms under shear to produce a strain, and furthermore, the opening of the wing cracks produce volume strain or dilatancy. In the presence of a confining pressure, microcrack formation may be suppressed, as is often the case for triaxial compression tests or natural underground stress situations. However, if the confining pressure is insufficient to suppress fracture, then the fractures will evolve with time to give the characteristic tertiary creep response. Two first order kinetics processes, closure of cracks and healing of cracks, control the healing process. Significantly, volume strain produced by microfractures may lead to changes in the permeability of the salt, which can become a major concern in cavern sealing and operation. The MDCF model is used in three simulations of field experiments in which indirect measures were obtained of the generation of damage. The results of the simulations help to verify the model and suggest that the model captures the correct fracture behavior of rock salt. The model is used in this work to estimate the generation and location of damage around a cylindrical storage cavern. The results are interesting because stress conditions around the cylindrical cavern do not lead to large amounts of damage. Moreover, the damage is such that general failure can not readily occur, nor does the extent of the damage suggest possible increased permeation when the surrounding salt is impermeable.

Chan, K.S.; Fossum, A.F.; Munson, D.E.

1999-03-01T23:59:59.000Z

33

Numerical evaluation of effective unsaturated hydraulic properties for fractured rocks  

Science Conference Proceedings (OSTI)

To represent a heterogeneous unsaturated fractured rock by its homogeneous equivalent, Monte Carlo simulations are used to obtain upscaled (effective) flow properties. In this study, we present a numerical procedure for upscaling the van Genuchten parameters of unsaturated fractured rocks by conducting Monte Carlo simulations of the unsaturated flow in a domain under gravity-dominated regime. The simulation domain can be chosen as the scale of block size in the field-scale modeling. The effective conductivity is computed from the steady-state flux at the lower boundary and plotted as a function of the averaging pressure head or saturation over the domain. The scatter plot is then fitted using van Genuchten model and three parameters, i.e., the saturated conductivity K{sub s}, the air-entry parameter {alpha}, the pore-size distribution parameter n, corresponding to this model are considered as the effective K{sub s}, effective {alpha}, and effective n, respectively.

Lu, Zhiming [Los Alamos National Laboratory; Kwicklis, Edward M [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

34

Spatial statistics for predicting flow through a rock fracture  

Science Conference Proceedings (OSTI)

Fluid flow through a single rock fracture depends on the shape of the space between the upper and lower pieces of rock which define the fracture. In this thesis, the normalized flow through a fracture, i.e. the equivalent permeability of a fracture, is predicted in terms of spatial statistics computed from the arrangement of voids, i.e. open spaces, and contact areas within the fracture. Patterns of voids and contact areas, with complexity typical of experimental data, are simulated by clipping a correlated Gaussian process defined on a N by N pixel square region. The voids have constant aperture; the distance between the upper and lower surfaces which define the fracture is either zero or a constant. Local flow is assumed to be proportional to local aperture cubed times local pressure gradient. The flow through a pattern of voids and contact areas is solved using a finite-difference method. After solving for the flow through simulated 10 by 10 by 30 pixel patterns of voids and contact areas, a model to predict equivalent permeability is developed. The first model is for patterns with 80% voids where all voids have the same aperture. The equivalent permeability of a pattern is predicted in terms of spatial statistics computed from the arrangement of voids and contact areas within the pattern. Four spatial statistics are examined. The change point statistic measures how often adjacent pixel alternate from void to contact area (or vice versa ) in the rows of the patterns which are parallel to the overall flow direction. 37 refs., 66 figs., 41 tabs.

Coakley, K.J.

1989-03-01T23:59:59.000Z

35

Foam flow through a transparent rough-walled rock fracture  

SciTech Connect

This paper presents an experimental study of nitrogen, water, and aqueous foam flow through a transparent replica of a natural rough-walled rock fracture with a hydraulic aperture of roughly 30 {mu}m. It is established that single-phase flow of both nitrogen and water is well described by analogy to flow between parallel plates. Inertial effects caused by fracture roughness become important in single-phase flow as the Reynolds number approaches 1. Foam exhibits effective control of gas mobility. Foam flow resistances are approximately 10 to 20 times greater than those of nitrogen over foam qualities spanning from 0.60 to 0.99 indicating effective gas-mobility control. Because previous studies of foam flow have focused mainly upon unfractured porous media, little information is available about foam flow mechanisms in fractured media. The transparency of the fracture allowed flow visualization and demonstrated that foam rheology in fractured media depends upon bubble shape and size. Changes in flow behavior are directly tied to transitions in bubble morphology.

Kovscek, A.; Tretheway, D.; Radke, C. [and others

1995-07-01T23:59:59.000Z

36

Modeling of thermally driven hydrological processes in partially saturated fractured rock  

E-Print Network (OSTI)

the heat source and encounters cooler rock, it condenses,fractured rock near the radioactive-decay heat source isrock, giving rise to a reflux of liquid back to the heat source.

Tsang, Yvonne

2010-01-01T23:59:59.000Z

37

Analyzing Unsatirated Flow Patterns in Fractured Rock Using an Integrated Modeling Approach  

Science Conference Proceedings (OSTI)

Characterizing percolation patterns in unsaturated fractured rock has posed a greater challenge to modeling investigations than comparable saturated zone studies, because of the heterogeneous nature of unsaturated media and the great number of variables impacting unsaturated flow. This paper presents an integrated modeling methodology for quantitatively characterizing percolation patterns in the unsaturated zone of Yucca Mountain, Nevada, a proposed underground repository site for storing high-level radioactive waste. The modeling approach integrates a wide variety of moisture, pneumatic, thermal, and isotopic geochemical field data into a comprehensive three-dimensional numerical model for modeling analyses. It takes into account the coupled processes of fluid and heat flow and chemical isotopic transport in Yucca Mountain's highly heterogeneous, unsaturated fractured tuffs. Modeling results are examined against different types of field-measured data and then used to evaluate different hydrogeological conceptualizations and their results of flow patterns in the unsaturated zone. In particular, this model provides a much clearer understanding of percolation patterns and flow behavior through the unsaturated zone, both crucial issues in assessing repository performance. The integrated approach for quantifying Yucca Mountain's flow system is demonstrated to provide a practical modeling tool for characterizing flow and transport processes in complex subsurface systems.

Y.S. Wu; G. Lu; K. Zhang; L. Pan; G.S. Bodvarsson

2006-08-03T23:59:59.000Z

38

Determination of permeability of granitic rocks in GT-2 from hydraulic fracturing data  

DOE Green Energy (OSTI)

The Los Alamos Scientific Laboratory is currently conducting a study to determine the feasibility to extract geothermal energy from dry hot rock. The investigated concept calls for the creation of a hydraulic fracture in hot, impermeable rock. Heat will be exchanged subsequently at the fracture surface between the rock and a circulating fluid. The successful creation of hydraulic fractures in the granitic section of exploratory holes GT-1 and GT-2 yielded sufficient data to calculate the average permeability of the rock next to a fracture by means of the mathematical model. The calculated permeabilities were found to be in the microdarcy range and proved the granitic rock penetrated by GT-1 and GT-2 to be sufficiently impermeable to test the above concept. (auth)

Delisle, G.

1975-11-01T23:59:59.000Z

39

MULTI-ATTRIBUTE SEISMIC/ROCK PHYSICS APPROACH TO CHARACTERIZING FRACTURED RESERVOIRS  

SciTech Connect

This project consists of three key interrelated Phases, each focusing on the central issue of imaging and quantifying fractured reservoirs, through improved integration of the principles of rock physics, geology, and seismic wave propagation. This report summarizes the results of Phase I of the project. The key to successful development of low permeability reservoirs lies in reliably characterizing fractures. Fractures play a crucial role in controlling almost all of the fluid transport in tight reservoirs. Current seismic methods to characterize fractures depend on various anisotropic wave propagation signatures that can arise from aligned fractures. We are pursuing an integrated study that relates to high-resolution seismic images of natural fractures to the rock parameters that control the storage and mobility of fluids. Our goal is to go beyond the current state-of-the art to develop and demonstrate next generation methodologies for detecting and quantitatively characterizing fracture zones using seismic measurements. Our study incorporates 3 key elements: (1) Theoretical rock physics studies of the anisotropic viscoelastic signatures of fractured rocks, including up scaling analysis and rock-fluid interactions to define the factors relating fractures in the lab and in the field. (2) Modeling of optimal seismic attributes, including offset and azimuth dependence of travel time, amplitude, impedance and spectral signatures of anisotropic fractured rocks. We will quantify the information content of combinations of seismic attributes, and the impact of multi-attribute analyses in reducing uncertainty in fracture interpretations. (3) Integration and interpretation of seismic, well log, and laboratory data, incorporating field geologic fracture characterization and the theoretical results of items 1 and 2 above. The focal point for this project is the demonstration of these methodologies in the Marathon Oil Company Yates Field in West Texas.

Gary Mavko

2000-10-01T23:59:59.000Z

40

FRACTURE DETECTION IN CRYSTALLINE ROCK USING ULTRASONIC SHEAR WAVES  

E-Print Network (OSTI)

the piezoelectric source plate and the rock surface. With aThe S^j sources were bonded to the rock surface with a fast-^ source plate was epoxied in position on the rock specimen.

Waters, K.H.

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Does hydraulic-fracturing theory work in jointed rock masses  

DOE Green Energy (OSTI)

The hypocenter locations of micro-earthquakes (acoustic emissions) generated during fracturing typically are distributed three-dimensionally suggesting that fracturing stimulates a volumetric region, rather than the planar fracture theoretically expected. The hypocenter maps generated at six operating, or potential, HDR reservoirs in the US, Europe and Japan are examined in detail and the fracture dimensions are correlated with fracture injection volumes and formation permeability. Depsite the volumetric appearance of the maps we infer that the induced fractures are mainly planar and may propagate aseismically. The induced seismicity stems from nearby joints, which are not opened significantly by fracturing, but are caused to shear-slip because of local pore pressure.

Murphy, H.D.; Keppler, H.; Dash, Z.V.

1983-01-01T23:59:59.000Z

42

Method and apparatus for determining two-phase flow in rock fracture  

DOE Patents (OSTI)

One object of the present invention to provide an improved method and apparatus for measuring the relative permeability of a rock fracture to multiple phases in a manner which will provide even more uniform delivery of both wetting and non-wetting phases to the fracture edge. It is another object of the invention to provide an improved method and apparatus for measuring the permeability of multiple phases through a rock fracture which comprises delivering the respective phases through manifold means to uniformly deliver the respective phases to and from opposite edges of the rock fracture in a distributed manner across the gap of the fracture wherein the manifold means for delivering the wetting phase comprises porous block means having a side facing the rock fracture edge and bore means therein for providing uniform distribution of the wetting phase to the porous block surfaces, and the manifold means for delivering the non-wetting phase include a plenum in communication with parallel grooves disposed on a surface of the porous means facing perpendicular to the rock fracture edge. These and other objects of the invention will be apparent from the following description and accompanying drawings.

Persoff, P.; Pruess, K.; Myer, L.

1992-12-31T23:59:59.000Z

43

Combined seismic and hydraulic method of modeling flow in fractured low permeability rocks  

DOE Green Energy (OSTI)

Modeling flow of ground water in hard rocks where a network of fractures provides the dominant flow paths is a major problem. This paper summarizes a program of investigations currently underway in this laboratory to characterize the geometry of fractured rocks and develop methods of handling flow in such systems. Numerical models have been developed to investigate flow behavior in two- and three-dimensional fracture networks. The results demonstrate the insights that can be gained from modeling studies of fractured rocks. A key problem is gathering the necessary data on fracture geometry. Investigations have been started to determine how vertical seismic profiling (VSP) might be improved and applied to this problem. A VSP experiment in The Geysers geothermal field in northern California, where fracture orientation is known, produced shear wave splitting and velocity anisotropy in agreement with theory. The results suggest the potential application of 3-component, multi-source VSP data in determining fracture orientation and average spacing. We believe a combination of seismic and hydraulic methods can greatly enhance an understanding of fluid flow and transport in low permeability rock systems where fractures provide the dominant paths. 40 refs, 16 figs., 4 tabs.

Witherspoon, P.A.; Long, J.C.S.; Majer, E.L.; Myer, L.R.

1987-06-01T23:59:59.000Z

44

Flow and transport in unsaturated fractured rock: effects of multiscale heterogeneity of  

E-Print Network (OSTI)

.g., porosity, permeability, and capillary parameters for rock matrix). Additionally, pneumatic pres- sure of calibration of fracture permeability, using pneumatic pressure data. The advective­diffusive equation., 1998). This model is based mainly on the hypothesis that only a portion of connected fractures

Zhou, Quanlin

45

Fluid Flow in Fractured Rock: Theory and Application  

E-Print Network (OSTI)

Porous Media, Pullman, WA, July 9-18,1989, and to be published in the Proceedings Fluid Flow in Fractured

Long, J.C.S.

2012-01-01T23:59:59.000Z

46

Experimental and Analytical Research on Fracture Processes in ROck  

DOE Green Energy (OSTI)

Experimental studies on fracture propagation and coalescence were conducted which together with previous tests by this group on gypsum and marble, provide information on fracturing. Specifically, different fracture geometries wsere tested, which together with the different material properties will provide the basis for analytical/numerical modeling. INitial steps on the models were made as were initial investigations on the effect of pressurized water on fracture coalescence.

Herbert H.. Einstein; Jay Miller; Bruno Silva

2009-02-27T23:59:59.000Z

47

Sizing of a hot dry rock reservoir from a hydraulic fracturing experiment  

DOE Green Energy (OSTI)

Hot dry rock (HDR) reservoirs do not lend themselves to the standard methods of reservoir sizing developed in the petroleum industry such as the buildup/drawdown test. In a HDR reservoir the reservoir is created by the injection of fluid. This process of hydraulic fracturing of the reservoir rock usually involves injection of a large volume (5 million gallons) at high rates (40BPM). A methodology is presented for sizing the HDR reservoir created during the hydraulic fracturing process. The reservoir created during a recent fracturing experiment is sized using the techniques presented. This reservoir is then investigated for commercial potential by simulation of long term power production. 5 refs., 7 figs.

Zyvoloski, G.

1985-01-01T23:59:59.000Z

48

Modeling flow and transport in unsaturated fractured rock: An evaluation of the continuum approach  

Science Conference Proceedings (OSTI)

Because the continuum approach is relatively simple and straightforward to implement, it has been commonly used in modeling flow and transport in unsaturated fractured rock. However, the usefulness of this approach can be questioned in terms of its adequacy for representing fingering flow and transport in unsaturated fractured rock. The continuum approach thus needs to be evaluated carefully by comparing simulation results with field observations directly related to unsaturated flow and transport processes. This paper reports on such an evaluation, based on a combination of model calibration and prediction, using data from an infiltration test carried out in a densely fractured rock within the unsaturated zone of Yucca Mountain, Nevada. Comparisons between experimental and modeling results show that the continuum approach may be able to capture important features of flow and transport processes observed from the test. The modeling results also show that matrix diffusion may have a significant effect on the overall transport behavior in unsaturated fractured rocks, which can be used to estimate effective fracture-matrix interface areas based on tracer transport data. While more theoretical, numerical, and experimental studies are needed to provide a conclusive evaluation, this study suggests that the continuum approach is useful for modeling flow and transport in unsaturated, densely fractured rock.

Liu, Hui-Hai; Haukwa, Charles B.; Ahlers, C. Fredrik; Bodvarsson, Gudmundur S.; Flint, Alan L.; Guertal, William B.

2002-09-01T23:59:59.000Z

49

Establishment of Stress-Permeabilty relationship of fractured rock mass by numerical modeling  

Office of Scientific and Technical Information (OSTI)

Accepted for publication in International Journal of Rock Mechanics & Mining Sciences Accepted for publication in International Journal of Rock Mechanics & Mining Sciences Stress-Dependent Permeability of Fractured Rock Masses: A Numerical Study Ki-Bok Min *1 , J Rutqvist 2 , Chin-Fu Tsang 2 , and Lanru Jing 1 1 Engineering Geology and Geophysics Research Group, Royal Institute of Technology (KTH), Stockholm, Sweden 2 Earth Sciences Division, Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA, USA * corresponding author. Tel.: +46-8-790-7919; fax: +46-8-790-6810. E-mail address: kibok@kth.se (Ki-Bok Min) 1 Abstract We investigate the stress-dependent permeability issue in fractured rock masses considering the effects of nonlinear normal deformation and shear dilation of fractures using a two-dimensional

50

Photo-Disintegration of the Iron Nucleus in Fractured Magnetite Rocks with Magnetostriction  

E-Print Network (OSTI)

There has been considerable interest in recent experiments on iron nuclear disintegrations observed when rocks containing such nuclei are crushed and fractured. The resulting nuclear transmutations are particularly strong for the case of magnetite rocks, i.e. loadstones. We argue that the fission of the iron nucleus is a consequence of photo-disintegration. The electro-strong coupling between electromagnetic fields and nuclear giant dipole resonances are central for producing observed nuclear reactions. The large electron energies produced during the fracture of piezomagnetic rocks are closely analogous to the previously discussed case of the fracture of piezoelectric rocks. In both cases electro-weak interactions can produce neutrons and neutrinos from energetic protons and electrons thus inducing nuclear transmutations. The electro-strong condensed matter coupling discussed herein represents new many body collective nuclear photo-disintegration effects.

A. Widom; J. Swain; Y. N. Srivastava

2013-06-25T23:59:59.000Z

51

Photo-Disintegration of the Iron Nucleus in Fractured Magnetite Rocks with Magnetostriction  

E-Print Network (OSTI)

There has been considerable interest in recent experiments on iron nuclear disintegrations observed when rocks containing such nuclei are crushed and fractured. The resulting nuclear transmutations are particularly strong for the case of magnetite rocks, i.e. loadstones. We argue that the fission of the iron nucleus is a consequence of photo-disintegration. The electro-strong coupling between electromagnetic fields and nuclear giant dipole resonances are central for producing observed nuclear reactions. The large electron energies produced during the fracture of piezomagnetic rocks are closely analogous to the previously discussed case of the fracture of piezoelectric rocks. In both cases electro-weak interactions can produce neutrons and neutrinos from energetic protons and electrons thus inducing nuclear transmutations. The electro-strong condensed matter coupling discussed herein represents new many body collective nuclear photo-disintegration effects.

Widom, A; Srivastava, Y N

2013-01-01T23:59:59.000Z

52

Proceedings of the Workshop on Numerical Modeling of Thermohydrological Flow in Fractured Rock Masses, Feb. 19-20, 1980, Berkeley, CA  

E-Print Network (OSTI)

and fluid flow in the hydraulic fracturing process." Ph.D.depth by means of hydraulic fracturing." in Rock Mechanics:production by hydraulic fracturing, the focus of fracture

Witherspoon, P.A.

2010-01-01T23:59:59.000Z

53

Results from a discrete fracture network model of a Hot Dry Rock system  

Science Conference Proceedings (OSTI)

The work described represents a move towards better representations of the natural fracture system. The discrete fracture network model used during the study was the NAPSAC code (Grindrod et al, 1992). The goals of the work were to investigate the application of discrete fracture network models to Hot Dry Rock systems, increase the understanding of the basic thermal extraction process and more specifically the understanding of the Rosemanowes Phase 2B system. The aim in applying the work to the Rosemanowes site was to use the discrete fracture network approach to integrate a diverse set of field measurements into as simple a model as possible.

Lanyon, G.W.; Batchelor, A.S.; Ledingham, P.

1993-01-28T23:59:59.000Z

54

Discrete element modeling of rock deformation, fracture network development and permeability evolution under hydraulic stimulation  

SciTech Connect

Key challenges associated with the EGS reservoir development include the ability to reliably predict hydraulic fracturing and the deformation of natural fractures as well as estimating permeability evolution of the fracture network with time. We have developed a physics-based rock deformation and fracture propagation simulator by coupling a discrete element model (DEM) for fracturing with a network flow model. In DEM model, solid rock is represented by a network of discrete elements (often referred as particles) connected by various types of mechanical bonds such as springs, elastic beams or bonds that have more complex properties (such as stress-dependent elastic constants). Fracturing is represented explicitly as broken bonds (microcracks), which form and coalesce into macroscopic fractures when external and internal load is applied. The natural fractures are represented by a series of connected line segments. Mechanical bonds that intersect with such line segments are removed from the DEM model. A network flow model using conjugate lattice to the DEM network is developed and coupled with the DEM. The fluid pressure gradient exerts forces on individual elements of the DEM network, which therefore deforms the mechanical bonds and breaks them if the deformation reaches a prescribed threshold value. Such deformation/fracturing in turn changes the permeability of the flow network, which again changes the evolution of fluid pressure, intimately coupling the two processes. The intimate coupling between fracturing/deformation of fracture networks and fluid flow makes the meso-scale DEM- network flow simulations necessary in order to accurately evaluate the permeability evolution, as these methods have substantial advantages over conventional continuum mechanical models of elastic rock deformation. The challenges that must be overcome to simulate EGS reservoir stimulation, preliminary results, progress to date and near future research directions and opportunities will be discussed. Methodology for coupling the DEM model with continuum flow and heat transport models will also be discussed.

Shouchun Deng; Robert Podgorney; Hai Huang

2011-02-01T23:59:59.000Z

55

Effects of dry fractures on matrix diffusion in unsaturated fractured rocks  

E-Print Network (OSTI)

Symposium on Multiphase Transport in Porous Media, ASMEmultiphase heat and mass flow in unsaturated fractured porous

Seol, Yongkoo; Liu, Hui Hai; Bodvarsson, Gudmundur S.

2002-01-01T23:59:59.000Z

56

Improvement of tubulars used for fracturing in hot dry rock wells  

DOE Green Energy (OSTI)

Completion of hot dry rock wells as it is currently envisioned, requires that hydraulic fracturing be used to develop a heat extraction reservoir and to provide low impedance flow paths between the designated water injection and production wells. Recent fracturing operations at measured depths from 11,400 ft to 15,300 ft at the Fenton Hill Hot Dry Rock Geothermal Test Site have resulted in numerous failures of tubulars caused by the high fracturing pressures, corrosive environment and large treatment volumes at high flow rates. Two new fracturing strings were designed and purchased. Physical and chemical properties exceeding API specifications were demanded and supplied by the manufacturers. These tubulars have performed to design specifications.

Nicholson, R.W.; Dreesen, D.S.; Turner, W.C.

1984-04-01T23:59:59.000Z

57

Dynamic fluid loss in hydraulic fracturing under realistic shear conditions in high-permeability rocks  

SciTech Connect

A study of the dynamic fluid loss of hydraulic fracturing fluids under realistic shear conditions is presented. During a hydraulic fracturing treatment, a polymeric solution is pumped under pressure down the well to create and propagate a fracture. Part of the fluid leaks into the rock formation, leaving a skin layer of polymer or polymer filter cake, at the rock surface or in the pore space. This study focuses on the effects of shear rate and permeability on dynamic fluid-loss behavior of crosslinked and linear fracturing gels. Previous studies of dynamic fluid loss have mainly been with low-permeability cores and constant shear rates. Here, the effect of shear history and fluid-loss additive on the dynamic leakoff of high-permeability cores is examined.

Navarrete, R.C.; Cawiezel, K.E.; Constien, V.G. [Dowell Schlumberger, Tulsa, OK (United States)

1996-08-01T23:59:59.000Z

58

Fluid effects on seismic waves in hard rocks with fractures and in soft granular media  

SciTech Connect

When fractures in otherwise hard rocks are filled with fluids (oil, gas, water, CO{sub 2}), the type and physical state of the fluid (liquid or gas) can make a large difference in the wave speeds and attenuation properties of seismic waves. The present work summarizes methods of deconstructing theses effects of fractures, together with any fluids contained within them, on wave propagation as observed in reflection seismic data. Additional studies of waves in fluid-saturated granular media show that the behavior can be quite different from that for fractured media, since these materials are typically much softer mechanically than are the fractured rocks (i.e., having a very small drained moduli). Important fluid effects in such media are often governed as much by fluid viscosity as by fluid bulk modulus.

Berryman, James G.

2009-03-01T23:59:59.000Z

59

Flow dynamics and potential for Biodegradation of Organic Contaminants in Fractured Rock Vadose Zones  

SciTech Connect

We present an experimental approach for investigating the potential for bioremediation of volatile organic chemicals (VOCs) in fractured-rock vadose zones. This approach is based on the coupling of fluid flow dynamics and biotransformation processes. Fluid flow and distribution within fracture networks may be a significant factor in the ability of microorganisms to degrade VOCs, as they affect the availability of substrate, moisture and nutrients. Biological activity can change liquid surface tension and generate biofilms that may change the nettability of solid surfaces, locally alter fracture permeability and redirect infiltrating liquids. Our approach has four components: (1) establishing a conceptual model for fluid and contaminant distribution in the geologic matrix of interest; (2) physical and numerical experiments of liquid seepage in the fracture plane; (3) non-destructive monitoring of biotransformations on rock surfaces at the micron-scale; and, (4) integration of flow and biological activity in natural rock ''geocosms''. Geocosms are core-scale flow cells that incorporate some aspects of natural conditions, such as liquid seepage in the fracture plane and moisture content. The experimental work was performed with rock samples and indigenous microorganisms from the site of the US Department of Energy's Idaho National Engineering and Environmental Laboratory (INEEL), located in a basalt flow basin where VOC contamination threatens the Snake River Aquifer. The insights gained from this approach should contribute to the design of techniques to monitor and stimulate naturally occurring biological activity and control the spread of organic contaminants.

Geller, J.T.; Holman, H.-Y.; Su, T.-S.; Liou, M.S.; Conrad, M.S.; Pruess, K.; Hunter-Devera, J.C.

1998-12-01T23:59:59.000Z

60

Training and Research on Probabilistic Hydro-Thermo-Mechanical Modeling of Carbon Dioxide Geological Sequestration in Fractured Porous Rocks  

SciTech Connect

Colorado School of Mines conducted research and training in the development and validation of an advanced CO{sub 2} GS (Geological Sequestration) probabilistic simulation and risk assessment model. CO{sub 2} GS simulation and risk assessment is used to develop advanced numerical simulation models of the subsurface to forecast CO2 behavior and transport; optimize site operational practices; ensure site safety; and refine site monitoring, verification, and accounting efforts. As simulation models are refined with new data, the uncertainty surrounding the identified risks decrease, thereby providing more accurate risk assessment. The models considered the full coupling of multiple physical processes (geomechanical and fluid flow) and describe the effects of stochastic hydro-mechanical (H-M) parameters on the modeling of CO{sub 2} flow and transport in fractured porous rocks. Graduate students were involved in the development and validation of the model that can be used to predict the fate, movement, and storage of CO{sub 2} in subsurface formations, and to evaluate the risk of potential leakage to the atmosphere and underground aquifers. The main major contributions from the project include the development of: 1) an improved procedure to rigorously couple the simulations of hydro-thermomechanical (H-M) processes involved in CO{sub 2} GS; 2) models for the hydro-mechanical behavior of fractured porous rocks with random fracture patterns; and 3) probabilistic methods to account for the effects of stochastic fluid flow and geomechanical properties on flow, transport, storage and leakage associated with CO{sub 2} GS. The research project provided the means to educate and train graduate students in the science and technology of CO{sub 2} GS, with a focus on geologic storage. Specifically, the training included the investigation of an advanced CO{sub 2} GS simulation and risk assessment model that can be used to predict the fate, movement, and storage of CO{sub 2} in underground formations, and the evaluation of the risk of potential CO{sub 2} leakage to the atmosphere and underground aquifers.

Gutierrez, Marte

2013-05-31T23:59:59.000Z

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

A numerical model of hydro-thermo-mechanical coupling in a fractured rock mass  

DOE Green Energy (OSTI)

Coupled hydro-thermo-mechanical codes with the ability to model fractured materials are used for predicting groundwater flow behavior in fractured aquifers containing thermal sources. The potential applications of such a code include the analysis of groundwater behavior within a geothermal reservoir. The capability of modeling hydro-thermo systems with a dual porosity, fracture flow model has been previously developed in the finite element code, FEHM. FEHM has been modified to include stress coupling with the dual porosity feature. FEHM has been further developed to implicitly couple the dependence of fracture hydraulic conductivity on effective stress within two dimensional, saturated aquifers containing fracture systems. The cubic law for flow between parallel plates was used to model fracture permeability. The Bartin-Bandis relationship was used to determine the fracture aperture within the cubic law. The code used a Newton Raphson iteration to implicitly solve for six unknowns at each node. Results from a model of heat flow from a reservoir to the moving fluid in a single fracture compared well with analytic results. Results of a model showing the increase in fracture flow due to a single fracture opening under fluid pressure compared well with analytic results. A hot dry rock, geothermal reservoir was modeled with realistic time steps indicating that the modified FEHM code does successfully model coupled flow problems with no convergence problems.

Bower, K.M.

1996-06-01T23:59:59.000Z

62

DOE/EA-1331: Environmental Assessment for Remediation of Subsurface and Groundwater Contamination at the Rock Springs In Situ Oil Shale Retort Site (07/31/00)  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

31 31 ENVIRONMENTAL ASSESSMENT REMEDIATION OF SUBSURFACE AND GROUNDWATER CONTAMINATION AT THE ROCK SPRINGS IN SITU OIL SHALE RETORT SITE SWEETWATER COUNTY, WYOMING July 2000 U.S. DEPARTMENT OF ENERGY NATIONAL ENERGY TECHNOLOGY LABORATORY ENVIRONMENTAL ASSESSMENT REMEDIATION OF SUBSURFACE AND GROUNDWATER CONTAMINATION AT THE ROCK SPRINGS IN SITU OIL SHALE RETORT SITE SWEETWATER COUNTY, WYOMING July 2000 Prepared by: U.S. Department of Energy National Energy Technology Laboratory NEPA COMPLIANCE SUMMARY SHEET LEAD AGENCY U.S. Department of Energy (DOE) TITLE Environmental Assessment for Remediation of Subsurface and Groundwater Contamination at the Rock Springs In Situ Oil Shale Retort Test Site; Sweetwater County Wyoming. CONTACT Additional copies or information concerning the Environmental Assessment (EA) can

63

Fracture Surface Area Effects on Fluid Extraction and the Electrical Resistivity of Geothermal Reservoir Rocks  

DOE Green Energy (OSTI)

Laboratory measurements of the electrical resistivity of fractured analogue geothermal reservoir rocks were performed to investigate the resistivity contrast caused by active boiling and to determine the effects of variable fracture dimensions and surface area on water extraction. Experiments were performed at confining pressures up to 10 h4Pa (100 bars) and temperatures to 170 C. Fractured samples show a larger resistivity change at the onset of boiling than intact samples. Monitoring the resistivity of fractured samples as they equilibrate to imposed pressure and temperature conditions provides an estimate of fluid migration into and out of the matrix. Measurements presented are an important step toward using field electrical methods to quantitatively search for fractures, infer saturation, and track fluid migration in geothermal reservoirs.

Roberts, J J; Detwiler, R L; Ralph, W; Bonner, B

2002-05-09T23:59:59.000Z

64

The effects of cultural noise on controlled source electromagnetic resonses of subsurface fractures in resistive terrain  

E-Print Network (OSTI)

Controlled source electromagnetic (CSEM) geophysics has been used with a fair amount of success in near surface hydrogeological studies. Recently, these investigations have been conducted frequently in human impacted field sites containing cultural conductors such as metal fences and buried pipes. Cultural noise adds an element of complexity to the geological interpretation of this type of data. This research investigates the influence of mutual induction between two buried targets in a CSEM experiment. In particular, it looks at the mutual coupling between a buried cultural conductor and a geological heterogeneity. We attempt to isolate the Hz field induced by tertiary currents in targets caused by mutual coupling. This is achieved with a Texas A&M 3D CSEM finite element code, which calculates the secondary Hz fields emanating from a target buried in a halfspace. Buried geological targets and cultural conductors are modeled as volumetric slabs embedded in a halfspace. A series of models have been simulated to study the effect of varying parameters such as target conductivity, transmitter location and shape of a target on the mutual inductance. In each case, the secondary Hz field is calculated for a model with two slabs, and two models with individual slabs. The mutual coupling is calculated by removing the secondary fields from the individual slab models from the response of a two slab model. The calculations of mutual inductance from a variety of such models suggests a complicated interaction of EM fields between the two targets. However, we can explain most of these complexities by adapting a simple approach to Maxwell’s equations. Although the tertiary Hz field is complicated, it may be useful in the characterization and delineation of electrical heterogeneities in the subsurface, which can then be related to geological features such as fractures or joints. It is seen that the most important factor affecting the mutual coupling is the host conductivity. The results have also shown that mutual coupling is very sensitive to transmitter (TX) location, especially when the TX is positioned near one of the targets.

Fernandes, Roland Anthony Savio

2008-05-01T23:59:59.000Z

65

Effect of Rock Transverse Isotropy on Stress Distribution and Wellbore Fracture  

E-Print Network (OSTI)

Unconventional oil and gas, which is of major interest in petroleum industry, often occur in reservoirs with transversely isotropic rock properties such as shales. Overlooking transverse isotropy may result in deviation in stress distribution around wellbore and inaccurate estimation of fracture initiation pressure which may jeopardize safe drilling and efficient fracturing treatment. In this work, to help understand the behavior of transversely isotropic reservoirs during drilling and fracturing, the principle of generalized plane-strain finite element formulation of anisotropic poroelastic problems is explained and a finite element model is developed from a plane-strain isotropic poroelastic model. Two numerical examples are simulated and the finite element results are compared with a closed form solution and another FE program. The validity of the developed finite element model is demonstrated. Using the validated finite element model, sensitivity analysis is carried out to evaluate the effects of transverse isotropy ratios, well azimuth, and rock bedding dip on pore pressure and stress distribution around a horizontal well. The results show that their effect cannot be neglected. The short term pore pressure distribution is sensitive to Young’ modulus ratio, while the long term pore pressure distribution is only sensitive to permeability ratio. The total stress distribution generally is not sensitive to transverse isotropy ratios. The effective stress and fracture initiation are very sensitive to Young’ modulus ratio. As the well rotates from minimum horizontal in-situ stress to maximum horizontal in-situ stress, the pore pressure and stress distributions tend to be more unevenly distributed around the wellbore, making the wellbore easier to fracture. The pore pressure and stress distributions tend to "rotate" in correspondence with the rock bedding plane. The fracture initiation potential and position will alter when rock bedding orientation varies.

Lu, Chunyang

2013-08-01T23:59:59.000Z

66

Simulation of rock fracture with the 3-D SHALE code  

SciTech Connect

The 3-D SHALE code simulates the propagation of stress waves and the occurrence of fracture in brittle solids. The physical models and numerical methods in this code are similar to those used in 2-D SHALE. We describe the 3-D code and present sample calculations for blasting in oil shale with a single isolated charge, an infinite array of charges, and an isolated pair of charges. These calculations illustrate the use of the code to simulate dynamic phenomena in complex geometric configurations. Some useful code improvements and possible applications are discussed. 8 references, 7 figures.

Nichols, B.D.; Adams, T.F.

1985-01-01T23:59:59.000Z

67

Electrical Resistivity as an Indicator of Saturation in Fractured Geothermal Reservoir Rocks: Experimental Data and Modeling  

DOE Green Energy (OSTI)

The electrical resistivity of rock cores under conditions representative of geothermal reservoirs is strongly influenced by the state and phase (liquid/vapor) of the pore fluid. In fractured samples, phase change (vaporization/condensation) can result in resistivity changes that are more than an order of magnitude greater than those measured in intact samples. These results suggest that electrical resistivity monitoring of geothermal reservoirs may provide a useful tool for remotely detecting the movement of water and steam within fractures, the development and evolution of fracture systems and the formation of steam caps. We measured the electrical resistivity of cores of welded tuff containing fractures of various geometries to investigate the resistivity contrast caused by active boiling and to determine the effects of variable fracture dimensions and surface area on water extraction from the matrix. We then used the Nonisothermal Unsaturated Flow and Transport model (NUFT) (Nitao, 1998) to simulate the propagation of boiling fronts through the samples. The simulated saturation profiles combined with previously reported measurements of resistivity-saturation curves allow us to estimate the evolution of the sample resistivity as the boiling front propagates into the rock matrix. These simulations provide qualitative agreement with experimental measurements suggesting that our modeling approach may be used to estimate resistivity changes induced by boiling in more complex systems.

Detwiler, R L; Roberts, J J

2003-06-23T23:59:59.000Z

68

Advanced Characterization of Fractured Reservoirs in Carbonate Rocks: The Michigan Basin  

Science Conference Proceedings (OSTI)

The main objective of this project is for a university-industry consortium to develop a comprehensive model for fracture carbonate reservoirs based on the ''data cube'' concept using the Michigan Basin as a prototype. This project combined traditional historical data with 2D and 3D seismic data as well as data from modern logging tools in a novel way to produce a new methodology for characterizing fractured reservoirs in carbonate rocks. Advanced visualization software was used to fuse the data and to image it on a variety of scales, ranging from basin-scale to well-scales.

Wood, James R.; Harrison, William B.

2000-10-24T23:59:59.000Z

69

Advanced Characterization of Fractured Reservoirs in Carbonate Rocks: The Michigan Basin  

SciTech Connect

The main objective of this project is for a university-industry consortium to develop a comprehensive model for fracture carbonate reservoirs based on the ''data cube'' concept using the Michigan Basin as a prototype. This project combined traditional historical data with 2D and 3D seismic data as well as data from modern logging tools in a novel way to produce a new methodology for characterizing fractured reservoirs in carbonate rocks. Advanced visualization software was used to fuse the data and to image it on a variety of scales, ranging from basin-scale to well-scales.

Wood, J.R.; Harrison, W.B.

2001-01-22T23:59:59.000Z

70

Insensitive explosive composition and method of fracturing rock using an extrudable form of the composition  

SciTech Connect

Insensitive explosive compositions were prepared by reacting di-isocyanate and/or poly-isocyanate monomers with an explosive diamine monomer. Prior to a final cure, the compositions are extrudable. The di-isocyanate monomers tend to produce tough, rubbery materials while polyfunctional monomers (i.e. having more than two isocyanate groups) tend to form rigid products. The extrudable form of the composition may be used in a variety of applications including rock fracturing.

Davis, Lloyd L

2013-11-05T23:59:59.000Z

71

Simulating Injectate/Rock Chemical Interaction In Fractured Desert Peak Quartz Monzonite  

DOE Green Energy (OSTI)

Simulations of the interactions of injected fluids with minerals within an engineered fracture in a sample of Desert Peak quartz monzonite were compared with experimental observations of fluid chemistry and fracture permeability. The observed decrease in permeability and effective hydraulic aperture was much more rapid ({approx}1.0 {micro}m/day) for a core injected with a mixed salt solution containing dissolved silica (near-saturation injectate), compared to cores injected with NaCl (far-from-saturation injectate) ({approx}0.1 {micro}m/day). Simulations were in qualitative agreement with these observations. Near-saturation injectate is predicted to result in net precipitation of secondary phases in the fracture ({approx}0.12 {micro}m/day), compared to a net dissolution of the rock for the far-from-saturation injectate ({approx}0.3 {micro}m/day). Permeability loss for the near-saturation-injectate is ascribed to precipitation in the fracture as well as potential dissolution of primary mineral asperities. Permeability loss for the far-from-saturation fluid is ascribed to dissolution of asperities and smoothing of the fracture. Post-test analysis of the fracture surface will be necessary to verify the processes occurring. The simplified geochemical models used do not account for mineral heterogeneity or for distributions of fluid residence times which could be important controls on permeability evolution. Further analysis is planned to explicitly account for these phenomena.

Viani, B; Roberts, J; Detwiler, R; Roberts, S; Carlson, S

2005-06-02T23:59:59.000Z

72

Effective-stress-law behavior of Austin chalk rocks for deformation and fracture conductivity  

SciTech Connect

Austin chalk core has been tested to determine the effective law for deformation of the matrix material and the stress-sensitive conductivity of the natural fractures. For deformation behavior, two samples provided data on the variations of the poroelastic parameter, {alpha}, for Austin chalk, giving values around 0.4. The effective-stress-law behavior of a Saratoga limestone sample was also measured for the purpose of obtaining a comparison with a somewhat more porous carbonate rock. {alpha} for this rock was found to be near 0.9. The low {alpha} for the Austin chalk suggests that stresses in the reservoir, or around the wellbore, will not change much with changes in pore pressure, as the contribution of the fluid pressure is small. Three natural fractures from the Austin chalk were tested, but two of the fractures were very tight and probably do not contribute much to production. The third sample was highly conductive and showed some stress sensitivity with a factor of three reduction in conductivity over a net stress increase of 3000 psi. Natural fractures also showed a propensity for permanent damage when net stressed exceeded about 3000 psi. This damage was irreversible and significantly affected conductivity. {alpha} was difficult to determine and most tests were inconclusive, although the results from one sample suggested that {alpha} was near unity.

Warpinski, N.R.; Teufel, L.W.

1994-08-01T23:59:59.000Z

73

Modeling Fluid Flow and Electrical Resistivity in Fractured Geothermal Reservoir Rocks  

DOE Green Energy (OSTI)

Phase change of pore fluid (boiling/condensing) in rock cores under conditions representative of geothermal reservoirs results in alterations of the electrical resistivity of the samples. In fractured samples, phase change can result in resistivity changes that are more than an order of magnitude greater than those measured in intact samples. These results suggest that electrical resistivity monitoring may provide a useful tool for monitoring the movement of water and steam within fractured geothermal reservoirs. We measured the electrical resistivity of cores of welded tuff containing fractures of various geometries to investigate the resistivity contrast caused by active boiling and to determine the effects of variable fracture dimensions and surface area on water extraction. We then used the Nonisothermal Unsaturated Flow and Transport model (NUFT) (Nitao, 1998) to simulate the propagation of boiling fronts through the samples. The simulated saturation profiles combined with previously reported measurements of resistivity-saturation curves allow us to estimate the evolution of the sample resistivity as the boiling front propagates into the rock matrix. These simulations provide qualitative agreement with experimental measurements suggesting that our modeling approach may be used to estimate resistivity changes induced by boiling in more complex systems.

Detwiler, R L; Roberts, J J; Ralph, W; Bonner, B P

2003-01-14T23:59:59.000Z

74

Evaluation of rock/fracture interactions during steam injection through vertical hydraulic fractures  

SciTech Connect

The design, results, and analysis of a steamdrive pilot in the South Belridge diatomite, Kern County, California, are reviewed. Pilot results demonstrate that steam can be injected across a 1,000-ft-tall diatomite column using hydraulically fractured wells and that significant oil is produced in response to steaming. A computationally simple numerical model is proposed and used to analyze reservoir heating and volumetric sweep by steam. Results from the analysis show that hydraulic fractures undergoing steam injection can be dynamic and asymmetrical.

Kovscek, A.R. [Stanford Univ., CA (United States); Johnston, R.M. [CalResources LLC, Bakersfield, CA (United States); Patzek, T.W. [Univ. of California, Berkeley, CA (United States)

1997-05-01T23:59:59.000Z

75

Two-phase flow visualization and relative permeability measurement in transparent replicas of rough-walled rock fractures  

DOE Green Energy (OSTI)

Understanding and quantifying multi-phase flow in fractures is important for mathematical and numerical simulation of geothermal reservoirs, nuclear waste repositories, and petroleum reservoirs. While the cubic law for single-phase flow has been well established for parallel-plate fractures theoretically and experimentally, no reliable measurements of multi-phase flow in fractures have been reported. This work reports the design and fabrication of an apparatus for visualization of two-phase flow and for measurement of gas-liquid relative permeability in realistic rough-walled rock fractures. A transparent replica of a natural rock fracture from a core specimen is fabricated by molding and casting in clear epoxy. Simultaneous flow of gas and liquid with control of capillary pressure at inlet and outlet is achieved with the Hassler sandwich'' design: liquid is injected to the fracture through a porous block, while gas is injected directly to the edge of the fracture through channels in the porous block. A similar arrangement maintains capillary separation of the two phases at the outlet. Pressure drops in each phase across the fracture, and capillary pressures at the inlet and outlet, are controlled by means of pumps and needle valves, and are measured by differential and absolute pressure transducers. The clear epoxy cast of the natural fracture preserves the geometry of the fracture and permits visual observation of phase distributions. The fracture aperture distribution can be estimated by filling the fracture with a dyed liquid, and making pointwise measurements of the intensity of transmitted light.

Persoff, P.; Pruess, K.; Myer, L.

1991-01-01T23:59:59.000Z

76

Fluid transport properties of rock fractures at high pressure and temperature. Progress report, July 1, 1976--June 30, 1977  

DOE Green Energy (OSTI)

Initial stages of a study on the fluid transport properties of rock at high pressure and temperature are reported. Emphasis is placed on the mechanical hydraulic interactions, in an attempt to clarify the process of fracture closure and its influence on fracture permeability. To determine the fluid transport properties of a fracture, the effect of surface roughness, geometry, and filling on fracture permeability was investigated. Permeability of these fractures was measured at various effective normal stresses at room temperature. The law of effective stress appears valid for fractures without filling but permeability of filled fractures is more sensitive to confining pressure than pore pressure. Permeability of smooth surfaces varied 5 to 0.5 darcys over a range of effective stresses from 0 to 3000 bars. Filled fractures were an order of magnitude more permeable.

Engelder, T.; Scholz, C.

1977-03-01T23:59:59.000Z

77

Advanced Conceptual Models for Unsaturated and Two-Phase Flow in Fractured Rock  

DOE Green Energy (OSTI)

This project was initiated in FY03. As of December 2003, we have accomplished the following: (1) We conducted a more detailed evaluation of the preliminary experiments used to develop our investigative approach. In those experiments, water was invaded at a variety of flow rates into an air-filled, two dimensional analog fracture network. Results demonstrated the critical control that fracture intersections place on two-phase flow in fracture networks. At low flows, capillary and gravitational forces combined to create a narrow pulsing flow structure that spanned the system vertically. At higher flows, viscous forces acted to remove the pulsation; however, the flow structure remained narrow. The intersections acted to impose a narrow ''slender ladder'' structure on the flowing phase that did not expand with depth, but instead remained focused. A manuscript documenting this effort has been published in Water Resources Research [Glass et al., 2003a]. (2) We initiated a collaborative relationship with a research group at Seoul National University. This group, which is led by Dr. Kang-Kun Lee is also using a combined experimental numerical approach to consider DNAPL migration in fracture networks. They are particularly interested in the influence of ambient groundwater flows, making their work complementary to ours. The first fruit of that collaboration is an article demonstrating that modification of an Invasion Percolation algorithm to include gravity and the first-order effects of viscous forces shows good agreement with physical experiments in a simplistic fracture network. Results were published in Geophysical Research Letters [Ji et al., 2003a]. (3) We carried out an extensive review of models for fracture networks. These include models developed from observations of networks on outcrops at several scales and stochastic models that are prevalent in the literature from the 1980s to very recent developments. The results of this review were included as par t of a review paper co-authored by Rajaram, which was submitted to Reviews in Geophysics [Molz et al., in press]. (4) We prepared a manuscript based on previous work that will be used to support the development of our new conceptual model(s) for transport in fractured rock. Eight experiments were conducted to evaluate the repeatability of flow under nearly identical conditions and to characterize general patterns in flow behavior. Collected data revealed that flow generally converged to a single fracture in the bottom row of blocks. Periods of pathway switching were observed to be more common than periods with steady, constant flow pathways. We noted the importance of fracture intersections for integrating uniform flow and discharging a ''fluid cascade'', where water advances rapidly to the next capillary barrier creating a stop and start advance of water through the network. The results of this simple experiment suggest that the interaction of multiple fracture intersections in a network creates flow behavior not generally recognized in popular conceptual and numerical models. A manuscript documenting this effort has been accepted for publication in Vadose Zone Journal [Wood et al., 2003]. (5) Slender transport pathways have been found in laboratory and field experiments within unsaturated fractured rock. We considered the simulation of such structures with a Modified form of Invasion Percolation (MIP). Results show that slender pathways form in fracture networks for a wide range of expected conditions, can be maintained when subsequent matrix imbibition is imposed, and may arise even in the context of primarily matrix flow due to the action of fractures as barriers to inter-matrix block transport. A manuscript documenting this effort has been submitted to Geophysical Research Letters [Glass et al., 2003b].

Rajaram, Harihar

2003-06-01T23:59:59.000Z

78

THE STATE OF THE ART OF NUMERICAL MODELING OF THERMOHYDROLOGIC FLOW IN FRACTURED ROCK MASSES  

E-Print Network (OSTI)

improving production by hydraulic fracturing 8 the focus otfor fractures. (d) Hydraulic Fracturing: The model has been

Wang, J.S.Y.

2013-01-01T23:59:59.000Z

79

Proceedings of the Second International Symposium on Dynamics of Fluids in Fractured Rock  

E-Print Network (OSTI)

new fracture surface by hydraulic fracturing. Termination ofwas impossible until hydraulic fracturing was applied. ForFor conventional hydraulic fracturing, this is not crucial

Faybishenko, Boris; Witherspoon, Paul A.

2004-01-01T23:59:59.000Z

80

Fractured rock modeling in the National Waste Terminal Storage Program: a review of requirements and status  

Science Conference Proceedings (OSTI)

Generalized computer codes capable of forming the basis for numerical models of fractured rock masses are being used within the NWTS program. Little additional development of these codes is considered justifiable, except in the area of representation of discrete fractures. On the other hand, model preparation requires definition of medium-specific constitutive descriptions and site characteristics and is therefore legitimately conducted by each of the media-oriented projects within the National Waste Terminal Storage program. However, it is essential that a uniform approach to the role of numerical modeling be adopted, including agreement upon the contribution of modeling to the design and licensing process and the need for, and means of, model qualification for particular purposes. This report discusses the role of numerical modeling, reviews the capabilities of several computer codes that are being used to support design or performance assessment, and proposes a framework for future numerical modeling activities within the NWTS program.

St. John, C.; Krug, A.; Key, S.; Monsees, J.

1983-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Evaluating the Moisture Conditions in the Fractured Rock at Yucca Mountain: The Impact of Natural Convection Processes in Heated Emplacement Drifts  

E-Print Network (OSTI)

THE FRACTURED ROCK AT YUCCA MOUNTAIN: THE IMPACT OF NATURALgeologic repository at Yucca Mountain, Nevada, will stronglyWaste Emplacement Drifts at Yucca Mountain, Nevada, Nuclear

Birkholzer, J.T.; Webb, S.W.; Halecky, N.; Peterson, P.F.; Bodvarsson, G.S.

2005-01-01T23:59:59.000Z

82

Evaluation of subsurface fracture geometry using fluid pressure response to solid earth tidal strain  

DOE Green Energy (OSTI)

The nature of solid earth tidal strain and surface load deformation due to the influence of gravitational forces and barometric pressure loading are discussed. The pore pressure response to these types of deformation is investigated in detail, including the cases of a confined aquifer intersected by a well and a discrete fracture intersected by a well. The integration of the tidal response method with conventional pump tests in order to independently calculate the hydraulic parameters of the fracture-formation system is discussed. How advanced spectral analysis methods, coupled with correlation analysis can be used to extract the tidal response signals from the pressure record is shown. Uncertainties in the signals are estimated using various information-theoretic methods in order to place a confidence level at which we can safely assume that the measured signal is indeed of tidal origin. A detailed case study of the method carried out at the Raft River Geothermal Reservoir in Idaho is presented. All of the analyzed tidal data is presented and the results of the computed fracture orientation using the solid earth tidal strain approach are compared with the extensive field work carried out at Raft River over the past decade. The direction that future work in the continuing development of this technology should take is discussed, including: (1) the present need for an expanded data base for the confirmation of present tidal strain response models, and (2) improvement in response models.

Hanson, J.M.

1984-09-01T23:59:59.000Z

83

Estimating Liquid Fluxes in Thermally Perturbed Fractured Rock Using Measured Temperature Profiles  

DOE Green Energy (OSTI)

A new temperature-profile method was recently developed for analyzing perturbed flow conditions in superheated porous media. The method uses high-resolution temperature data to estimate the magnitude of the heat-driven liquid and gas fluxes that form as a result of boiling, condensation, and recirculation of pore water. In this paper, we evaluate the applicability of this new method to the more complex flow behavior in fractured formations with porous rock matrix. In such formations, with their intrinsic heterogeneity, the porous but low-permeable matrix provides most of the mass and heat storage capacity, and dominates conductive heat transfer, Fractures, on the other hand, offer highly effective conduits for gas and liquid flow, thereby generating significant convective heat transfer. After establishing the accuracy of the temperature-profile method for fractured porous formations, we apply the method in analyzing the perturbed flow conditions in a large-scale underground heater test conducted in unsaturated fractured porous tuff. The flux estimates for this test indicate a significant reflux of water near the heat source, on the order of a few hundred millimeter per year-much larger than the ambient percolation flux of only a few millimeter per year.

J.T. Birkholzer

2005-02-14T23:59:59.000Z

84

Inert and Reacting Tracers for Reservoir Sizing in Fractured, Hot Dry Rock Systems  

SciTech Connect

Flow characterization and volumetric sizing techniques using tracers in fractured hot dry rock reservoirs are discussed. Statistical methods for analyzing the residence time distribution (RTD) are presented. Tracer modal volumes and RTD shape are correlated with reservoir performance parameters such as active heat transfer area and dispersion levels. Chemically reactive tracers are proposed for mapping advance rates of cooled regions in HDR reservoirs, providing early warning of thermal drawdown. Important reaction rate parameters are identified for screening potential tracers. Current laboratory research and field work is reviewed.

Tester, J.W.; Robinson, B.A.; Ferguson, J.H.

1986-01-21T23:59:59.000Z

85

Coupled thermohydromechanical analysis of a heater test in unsaturated clay and fractured rock at Kamaishi Mine  

E-Print Network (OSTI)

injection and hydraulic fracturing stress measurements inlevel measured with hydraulic fracturing (reproduced from

Rutqvist, J.

2011-01-01T23:59:59.000Z

86

Rock deformation in hydrothermal systems: the nature of fractures in plutons and their host rocks. Technical progress report  

DOE Green Energy (OSTI)

The purpose of this program is to accumulate the types of field data which are important for the analysis of magma-hydrothermal systems. The structural effects of thermal processes were identified in order to distinguish the thermally induced deformations from the deformations that occurred subsequent to complete cooling of the system. Mapping techniques were developed to record the structural data on the ground from local domains characteristic of larger areas in the magma chamber, and in the air from low-angle oblique aerial photography of the entire region. The ground system is complete and preliminary testing is currently being carried out to verify the method. The results indicate that granitic crystalline rocks have no structural resistance to thermal perturbations. If nuclear wastes are to be stored in granite, precautionary buffers would have to be incorporated into the system. A total of 30 fossil magma chambers have been studied over the past 2 years. An extensive set of fracture imagery has been collected, together with information related to the geological history of the plutons. Fossil magma chambers in Arizona, Utah, California, Washington, Montana, and British Columbia have been studied.

Norton, D.

1981-11-01T23:59:59.000Z

87

A STATISTICAL FRACTURE MECHANICS APPROACH TO THE STRENGTH OF BRITTLE ROCK  

E-Print Network (OSTI)

Carlsson, H. , "Hydraulic fracturing and overcoring stress1949). Haimson, B.C. , "Hydraulic fracturing in porous andc.B. , "Laboratory hydraulic fracturing experiments in

Ratigan, J.L.

2010-01-01T23:59:59.000Z

88

A triple-continuum approach for modeling flow and transport processes in fractured rock  

E-Print Network (OSTI)

Multiphase Tracer Transport in Heterogeneous Fractured Porousmultiphase, nonisothermal flow and solute transport in fractured porousmultiphase fluid flow, heat transfer, and chemical migration in a fractured porous

Wu, Yu-Shu; Liu, H.H.; Bodvarsson, G.S; Zellmer, K .E.

2001-01-01T23:59:59.000Z

89

Laboratory and Field Measurements of Electrical Resistivity to Determine Saturation and Detect Fractures in a Heated Rock Mass  

DOE Green Energy (OSTI)

Laboratory measurements of the electrical resistivity of intact and fractured representative geothermal reservoir rocks were performed to investigate the resistivity contrast caused by active boiling and to infer saturation and fracture location in a large-scale field test. Measurements were performed to simulate test conditions with confining pressures up to 100 bars and temperatures to 145 C. Measurements presented are a first step toward making the search for fractures using electrical methods quantitatively. Intact samples showed a gradual resistivity increase when pore pressure was decreased below the phase-boundary pressure of free water, while fractured samples show a larger resistivity change at the onset of boiling. The resistivity change is greatest for samples with the most exposed surface area. Analysis of a field test provided the opportunity to evaluate fracture detection using electrical methods at a large scale. Interpretation of electrical resistance tomography (ERT) images of resistivity contrasts, aided by laboratory derived resistivity-saturation-temperature relationships, indicates that dynamic saturation changes in a heated rock mass are observable and that fractures experiencing drying or resaturation can be identified. The same techniques can be used to locate fractures in geothermal reservoirs using electrical field methods.

Roberts, J J; Ramirez, A; Carlson, S; Ralph, W; Bonner, B P

2001-04-03T23:59:59.000Z

90

On Water Flow in Hot Fractured Rock -- A Sensitivity Study on the Impact of Fracture-Matrix Heat Transfer  

E-Print Network (OSTI)

of multiphase, multicomponent fluid mixtures in porous andmultiphase heat and mass flow in unsaturated fractured porous

Birkholzer, Jens T.; Zhang, Yingqi

2005-01-01T23:59:59.000Z

91

Using seismic tomography to characterize fracture systems induced by hydraulic fracturing  

DOE Green Energy (OSTI)

Microearthquakes induced by hydraulic fracturing have been studied by many investigators to characterize fracture systems created by the fracturing process and to better understand the locations of energy resources in the earth`s subsurface. The pattern of the locations often contains a great deal of information about the fracture system stimulated during the hydraulic fracturing. Seismic tomography has found applications in many areas for characterizing the subsurface of the earth. It is well known that fractures in rock influence both the P and S velocities of the rock. The influence of the fractures is a function of the geometry of the fractures, the apertures and number of fractures, and the presence of fluids in the fractures. In addition, the temporal evolution of the created fracture system can be inferred from the temporal changes in seismic velocity and the pattern of microearthquake locations. Seismic tomography has been used to infer the spatial location of a fracture system in a reservoir that was created by hydraulic fracturing.

Fehler, M.; Rutledge, J.

1995-01-01T23:59:59.000Z

92

Quantitative model of vapor dominated geothermal reservoirs as heat pipes in fractured porous rock  

DOE Green Energy (OSTI)

We present a numerical model of vapor-dominated reservoirs which is based on the well-known conceptual model of White, Muffler, and Truesdell. Computer simulations show that upon heat recharge at the base, a single phase liquid-dominated geothermal reservoir in fractured rock with low matrix permeability will evolve into a two-phase reservoir with B.P.D. (boiling point-for-depth) pressure and temperature profiles. A rather limited discharge event through cracks in the caprock, involving loss of only a few percent of fluids in place, is sufficient to set the system off to evolve a vapor-dominated state. The attributes of this state are discussed, and some features requiring further clarification are identified. 26 refs., 5 figs.

Pruess, K.

1985-03-01T23:59:59.000Z

93

Modeling of thermally driven hydrological processes in partially saturated fractured rock  

Science Conference Proceedings (OSTI)

This paper is a review of the research that led to an in-depth understanding of flow and transport processes under strong heat stimulation in fractured, porous rock. It first describes the anticipated multiple processes that come into play in a partially saturated, fractured porous volcanic tuff geological formation, when it is subject to a heat source such as that originating from the decay of radionuclides. The rationale is then given for numerical modeling being a key element in the study of multiple processes that are coupled. The paper outlines how the conceptualization and the numerical modeling of the problem evolved, progressing from the simplified to the more realistic. Examples of numerical models are presented so as to illustrate the advancement and maturation of the research over the last two decades. The most recent model applied to in situ field thermal tests is characterized by (1) incorporation of a full set of thermal-hydrological processes into a numerical simulator, (2) realistic representation of the field test geometry, in three dimensions, and (3) use of site-specific characterization data for model inputs. Model predictions were carried out prior to initiation of data collection, and the model results were compared to diverse sets of measurements. The approach of close integration between modeling and field measurements has yielded a better understanding of how coupled thermal hydrological processes produce redistribution of moisture within the rock, which affects local permeability values and subsequently the flow of liquid and gases. The fluid flow in turn will change the temperature field. We end with a note on future research opportunities, specifically those incorporating chemical, mechanical, and microbiological factors into the study of thermal and hydrological processes.

Tsang, Yvonne; Birkholzer, Jens; Mukhopadhyay, Sumit

2009-03-15T23:59:59.000Z

94

Rock matrix and fracture analysis of flow in western tight gas sands  

SciTech Connect

Advanced core analysis includes measurements on the matrix properties of the rock. Matrix properties are important even in fractured wells since it is these properties which determine the rate of gas flow into the fractures. Cores are being tested from the fluvial, coastal, and paludal zones of the Mesaverde. At least two cores from each of these zones from all three wells will be analyzed. Properties measured include permeability as a function of confining pressure over the range of 500 to 5000 psi. A minimum of two Klinkenberg permeabilities are being determined from at least five data points. Interpretation includes estimates of pore size from gas slippage. Water adsorption and desorption isotherms will be determined for selected samples with data points being obtained at the following relative humidities: 0, 20, 40, 60, 75, 90, 92, 95 and 98. Porosity measurements from both thin section examination and volumetric measurements are being made. These results will be compared with the porosities of the cored internals determined from logs.

Morrow, N.R.; Brower, K.R.; Ward, J.S.

1985-01-01T23:59:59.000Z

95

Rock-Fluid Chemistry Impacts on Shale Hydraulic Fracture and Microfracture Growth  

E-Print Network (OSTI)

The role of surface chemical effects in hydraulic fracturing of shale is studied using the results of unconfined compression tests and Brazilian tests on Mancos shale- cored at depths of 20-60 ft. The rock mineralogy, total organic carbon and cation exchange capacity were determined in order to characterize the shale. Adsorption tests to study the interaction of the shale and aqueous fluid mixture were also carried out using surface tension measurements. The uniaxial compressive strengths and tensile strengths of individual shale samples after four hours exposure to water, 2.85 x 10^-3 M cationic surfactant (dodecyltrimethylammonium bromide-DTAB) and 2.81 x 10^-3 M anionic surfactant (sodium dodecylbenzenesulfonate-SDBS) were analyzed using ANOVA and Bonferroni tests. These mechanical strengths were largely reduced on exposure to the aqueous environments studied, despite the relatively low clay and low swelling clay content of the Mancos shale. Further comparison of the uniaxial compressive strengths and tensile strengths of the shale on exposure to water, to the strengths when exposed to the surfactant solutions showed that their difference was not statistically significant indicating that exposure to water had the greatest effect on strength loss. The surface tension measurement of 2.85 x 10^-4 M DTAB and 2.81 x 10^-4 M SDBS solutions before and after equilibration with shale showed about 80% increase in surface tension in the DTAB solution and 10% increase in surface tension in the SDBS solution. The probable sorption mechanism is electrostatic attraction with negatively charged sites of the shale as shown by significant loss of the cationic surfactant (DTAB) to the shale surface, and the relatively minor adsorption capacity of the anionic surfactant (SDBS). Although these adsorption tests indicate interaction between the shale and surfactant solutions, within the number of tests carried out and the surfactant concentration used, the interaction does not translate into a significant statistical difference for impacts of surfactants on mechanical strength of this shale compared to the impact of water alone. The relevance of this work is to facilitate the understanding of how the strength of rock can be reduced by the composition of hydraulic fracturing fluids, to achieve improved fracture performance and higher recovery of natural gas from shale reservoirs.

Aderibigbe, Aderonke

2012-05-01T23:59:59.000Z

96

Proceedings of the Second International Symposium on Dynamics of Fluids in Fractured Rock  

E-Print Network (OSTI)

modeling fluid and heat flow in fractured porous media. Soc.Modelling Fluid and Heat Flow in Fractured Porous Media. SPEmodeling fluid and heat flow in fractured porous media. Soc

Faybishenko, Boris; Witherspoon, Paul A.

2004-01-01T23:59:59.000Z

97

Identifying Fracture Types and Relative Ages Using Fluid Inclusion Stratigraphy  

DOE Green Energy (OSTI)

Enhanced Geothermal Systems (EGS) are designed to recover heat from the subsurface by mechanically creating fractures in subsurface rocks. Understanding the life cycle of a fracture in a geothermal system is fundamental to the development of techniques for creating fractures. Recognizing the stage of a fracture, whether it is currently open and transmitting fluids; if it recently has closed; or if it is an ancient fracture would assist in targeting areas for further fracture stimulation. Identifying dense fracture areas as well as large open fractures from small fracture systems will also assist in fracture stimulation selection. Geothermal systems are constantly generating fractures, and fluids and gases passing through rocks in these systems leave small fluid and gas samples trapped in healed microfractures. Fluid inclusions trapped in minerals as the fractures heal are characteristic of the fluids that formed them, and this signature can be seen in fluid inclusion gas analysis. Our hypothesis is that fractures over their life cycle have different chemical signatures that we can see in fluid inclusion gas analysis and by using the new method of fluid inclusion stratigraphy (FIS) the different stages of fractures, along with an estimate of fracture size can be identified during the well drilling process. We have shown with this study that it is possible to identify fracture locations using FIS and that different fractures have different chemical signatures however that signature is somewhat dependent upon rock type. Open, active fractures correlate with increase concentrations of CO2, N2, Ar, and to a lesser extent H2O. These fractures would be targets for further enhancement. The usefulness of this method is that it is low cost alternative to current well logging techniques and can be done as a well is being drilled.

Dilley, Lorie M.; Norman, David; Owens, Lara

2008-06-30T23:59:59.000Z

98

ADVANCED CHARACTERIZATION OF FRACTURED RESERVOIRS IN CARBONATE ROCKS: THE MICHIGAN BASIN  

Science Conference Proceedings (OSTI)

The purpose of the study was to collect and analyze existing data on the Michigan Basin for fracture patterns on scales ranging form thin section to basin. The data acquisition phase has been successfully concluded with the compilation of several large digital databases containing nearly all the existing information on formation tops, lithology and hydrocarbon production over the entire Michigan Basin. These databases represent the cumulative result of over 80 years of drilling and exploration. Plotting and examination of these data show that contrary to most depictions, the Michigan Basin is in fact extensively faulted and fractured, particularly in the central portion of the basin. This is in contrast to most of the existing work on the Michigan Basin, which tends to show relatively simple structure with few or minor faults. It also appears that these fractures and faults control the Paleozoic sediment deposition, the subsequent hydrocarbon traps and very likely the regional dolomitization patterns. Recent work has revealed that a detailed fracture pattern exists in the interior of the Central Michigan Basin, which is related to the mid-continent gravity high. The inference is that early Precambrian, ({approx}1 Ga) rifting events presumed by many to account for the gravity anomaly subsequently controlled Paleozoic sedimentation and later hydrocarbon accumulation. There is a systematic relationship between the faults and a number of gas and oil reservoirs: major hydrocarbon accumulations consistently occur in small anticlines on the upthrown side of the faults. The main tools used in this study to map the fault/fracture patterns are detailed, close-interval (CI = 10 feet) contouring of the formation top picks accompanied by a new way of visualizing the data using a special color spectrum to bring out the third dimension. In addition, recent improvements in visualization and contouring software were instrumental in the study. Dolomitization is common in the Michigan Basin, and it is crucial in developing reservoir quality rocks in some fields. Data on the occurrence of dolomite was extracted from driller's reports for all reported occurrences in Michigan, nearly 50 fields and over 500 wells. A digital database was developed containing the geographic location of all these wells (latitude-longitude) as well as the elevation of the first encounter of dolomite in the field/reservoir. Analysis shows that these dolomite occurrences are largely confined to the center of the basin, but with some exceptions, such as N. Adams Field. Further, some of the dolomite occurrences show a definite relationship to the fracture pattern described above, suggesting a genetic relationship that needs further work. Other accomplishments of this past reporting period include obtaining a complete land grid for the State of Michigan and further processing of the high and medium resolution DEM files. We also have measured new fluid inclusion data on dolomites from several fields that suggest that the dolomitization occurred at temperatures between 100 and 150 C. Finally, we have extracted the lithologic data for about 5000 wells and are in the process of integrating this data into the overall model for the Michigan Basin.

James R. Wood; William B. Harrison

2002-12-01T23:59:59.000Z

99

Parameter estimation from flowing fluid temperature logging data in unsaturated fractured rock using multiphase inverse modeling  

E-Print Network (OSTI)

modeling fluid and heat flow in fractured porous media, Soc.fluid and heat flows of multiphase, multicomponent fluid mixtures in porous and fractured media.

Mukhopadhyay, S.

2009-01-01T23:59:59.000Z

100

Topical report on subsurface fracture mapping from geothermal wellbores. Phase I. Pulsed radar techniques. Phase II. Conventional logging methods. Phase III. Magnetic borehole ranging  

DOE Green Energy (OSTI)

To advance the state-of-the-art in Hot Dry Rock technology, an evaluation is made of (i) the use of radar to map far-field fractures, (ii) the use of more than twenty different conventional well logging tools to map borehole-fracture intercepts, and (iii) the use of magnetic dipole ranging to determine the relative positions of the injection well and the production well within the fractured zone. It is found that according to calculations, VHF backscatter radar has the potential for mapping fractures within a distance of 50 +- 20 meters from the wellbore. A new technique for improving fracture identification is presented. Analyses of extant data indicate that when used synergistically the (1) caliper, (2) resistivity dipmeter, (3) televiewer, (4) television, (5) impression packer, and (6) acoustic transmission are useful for mapping borehole-fracture intercepts. Improvements in both data interpretation techniques and high temperature operation are required. The surveying of one borehole from another appears feasible at ranges of up to 200 to 500 meters by using a low frequency magnetic field generated by a moderately strong dipole source (a solenoid) located in one borehole, a sensitive B field detector that traverses part of the second borehole, narrow band filtering, and special data inversion techniques.

Hartenbaum, B.A.; Rawson, G.

1980-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

EA-1331: Remediation of Subsurface and Groundwater Contamination...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Remediation of Subsurface and Groundwater Contamination at the Rock Springs in situ Oil Shale Retort Site, Sweetwater County, Wyoming EA-1331: Remediation of Subsurface and...

102

ADVANCED CHARACTERIZATION OF FRACTURED RESERVOIRS IN CARBONATE ROCKS: THE MICHIGAN BASIN  

Science Conference Proceedings (OSTI)

Progress in year 2 of this project is highlighted by the completing of the writing and testing of the project database, ''Atlas'', and populating it with all the project data gathered to date. This includes digitization of 17,000+ original Scout Tickets for the Michigan Basin. Work continues on the Driller's Reports, where they have scanned about 50,000 pages out of an estimated 300,000 pages. All of the scanned images have been attached to ''Atlas'', the visual database viewer developed for this project. A complete set of the 1/24,000 USGS DEM (Digital Elevation Models) for the State of Michigan has been downloaded from the USGS Web sites, decompressed and converted to ArcView Grid files. A large-scale map (48 inches x 84 inches) has been constructed by mosaicking of the high-resolution files. This map shows excellent ground surface detail and has drawn much comment and requests for copies at the venues where it has been displayed. Although it was generated for mapping of surface lineations the map has other uses, particularly analysis of the glacial drift in Michigan. It presents unusual problems due to its size and they are working with vendors on compression and display algorithms (e.g. MrSID{copyright}) in an attempt to make it available over the Internet, both for viewing and download. A set of aeromagnetic data for the Michigan Basin has been acquired and is being incorporated into the study. As reported previously, the general fracture picture in the Michigan Basin is a dominant NW-SE trend with a conjugate NE-SW trend. Subsurface, DEM and gravity data support the interpretation of a graben-type deep basement structural trend coincident with the Michigan Basin Gravity High. They plan to incorporate the aeromagnetic data into this interpretation as well.

James R. Wood; William B. Harrison

2000-04-01T23:59:59.000Z

103

On Water Flow in Hot Fractured Rock -- A Sensitivity Study on the Impact of Fracture-Matrix Heat Transfer  

E-Print Network (OSTI)

is related to the heat transfer between the two phasespossibly be affected. Heat transfer from the matrix can beof Fracture-Matrix Heat Transfer Jens T. Birkholzer and

Birkholzer, Jens T.; Zhang, Yingqi

2005-01-01T23:59:59.000Z

104

The Combined Finite-Discrete Element Method applied to the Study of Rock Fracturing Behavior in 3D  

Science Conference Proceedings (OSTI)

Since its introduction the combined finite-discrete element method (FEM/DEM), has become an excellent tool to address a wide range of problems involving fracturing and fragmentation of solids. Within the context of rock mechanics, the FEM/DEM method has been applied to many complex industrial problems such as block caving, deep mining techniques, rock blasting, seismic waves, packing problems, rock crushing problems, etc. In the real world most of the problems involving fracture and fragmentation of solids are three dimensional problems. With the aim of addressing these problems an improved 2D/3D FEM/DEM capability has been developed at Los Alamos National Laboratory (LANL). These capabilities include state of the art 3D contact detection, contact interaction, constitutive material models, and fracture models. In this paper, Split Hopkinson Pressure Bar (SHPB) Brazilian experiments are simulated using this improved 2D/3D FEM/DEM approach which is implemented in LANL's MUNROU (Munjiza-Rougier) code. The results presented in this work show excellent agreement with both the SHPB experiments and previous 2D numerical simulations performed by other FEM/DEM research groups.

Rougier, Esteban [Los Alamos National Laboratory; Bradley, Christopher R. [Los Alamos National Laboratory; Broom, Scott T. [Geomechanics Sandia National Laboratories; Knight, Earl E. [Los Alamos National Laboratory; Munjiza, Ante [School of Engineering and Material Sciences, Queen Mary, University of London; Sussman, Aviva J. [Los Alamos National Laboratory; Swift, Robert P. [Los Alamos National Laboratory

2011-01-01T23:59:59.000Z

105

An integrated methodology for sub-surface fracture characterization using microseismic data: A case study at the NW Geysers  

Science Conference Proceedings (OSTI)

Geothermal and unconventional hydrocarbon reservoirs are often characterized by low permeability and porosity. So, they are difficult to produce and require stimulation techniques, such as thermal shear deactivation and hydraulic fracturing. Fractures ... Keywords: Fuzzy clustering, Geothermal reservoirs, Microseismic, Shear wave splitting, Tomographic inversion, Unconventional hydrocarbon reservoirs

Fred Aminzadeh, Tayeb A. Tafti, Debotyam Maity

2013-04-01T23:59:59.000Z

106

On Water Flow in Hot Fractured Rock -- A Sensitivity Study on the Impact of Fracture-Matrix Heat Transfer  

E-Print Network (OSTI)

phases stored in matrix pores, the energy E M contained in VEnough energy is transmitted from the matrix to effectivelyfor energy transfer from the adjacent hot rock matrix rather

Birkholzer, Jens T.; Zhang, Yingqi

2005-01-01T23:59:59.000Z

107

U.S. National Committee for Rock Mechanics; and Conceptual model of fluid infiltration in fractured media. Project summary, July 28, 1997--July 27, 1998  

SciTech Connect

The title describes the two tasks summarized in this report. The remainder of the report contains information on meetings held or to be held on the subjects. The US National Committee for Rock Mechanics (USNC/RM) provides for US participation in international activities in rock mechanics, principally through adherence to the International Society for Rock Mechanics (ISRM). It also keeps the US rock mechanics community informed about new programs directed toward major areas of national concern in which rock mechanics problems represent critical or limiting factors, such as energy resources, excavation, underground storage and waste disposal, and reactor siting. The committee also guides or produces advisory studies and reports on problem areas in rock mechanics. A new panel under the auspices of the US National Committee for Rock Mechanics has been appointed to conduct a study on Conceptual Models of Fluid Infiltration in Fractured Media. The study has health and environmental applications related to the underground flow of pollutants through fractured rock in and around mines and waste repositories. Support of the study has been received from the US Nuclear Regulatory Commission and the Department of Energy`s Yucca Mountain Project Office. The new study builds on the success of a recent USNC/RM report entitled Rock Fractures and Fluid Flow: Contemporary Understanding and Applications (National Academy Press, 1996, 551 pp.). A summary of the new study is provided.

1998-09-01T23:59:59.000Z

108

A Reaction-Transport Model for Calcite Precipitation andEvaluation of Infiltration Fluxes in unsaturated fractured rock  

Science Conference Proceedings (OSTI)

The percolation flux in the unsaturated zone (UZ) is an important parameter addressed in site characterization and flow and transport modeling of the potential nuclear-waste repository at Yucca Mountain, NV, USA. The US Geological Survey (USGS) has documented hydrogenic calcite abundances in fractures and lithophysal cavities at Yucca Mountain to provide constraints on percolation fluxes in the UZ. The purpose of this study was to investigate the relationship between percolation flux and measured calcite abundances using reactive transport modeling. Our model considers the following essential factors affecting calcite precipitation: (1) infiltration, (2) the ambient geothermal gradient, (3) gaseous CO2 diffusive transport and partitioning in liquid and gas phases, (4) fracture matrix interaction for water flow and chemical constituents, and (5) water rock interaction. Over a bounding range of 2 20 mm/year infiltration rate, the simulated calcite distributions capture the trend in calcite abundances measured in a deep borehole (WT-24) by the USGS. The calcite is found predominantly in fractures in the welded tuffs, which is also captured by the model simulations. Simulations showed that from about 2 to 6 mm/year, the amount of calcite precipitated in the welded Topopah Spring tuff is sensitive to the infiltration rate. This dependence decreases at higher infiltration rates owing to a modification of the geothermal gradient from the increased percolation flux. The model also confirms the conceptual model for higher percolation fluxes in the fractures compared to the matrix in the welded units, and the significant contribution of Ca from water rock interaction. This study indicates that reactive transport modeling of calcite deposition can yield important constraints on the unsaturated zone infiltration-percolation flux and provide useful insight into processes such as fracture matrix interaction as well as conditions and parameters controlling calcite deposition.

Xu, Tianfu; Sonnenthal, Eric; Bodvarsson, Gudmundur

2001-06-15T23:59:59.000Z

109

Unsaturated flow and transport through fractured rock related to high-level waste repositories; Final report, Phase 3  

SciTech Connect

Research results are summarized for a US Nuclear Regulatory Commission contract with the University of Arizona focusing on field and laboratory methods for characterizing unsaturated fluid flow and solute transport related to high-level radioactive waste repositories. Characterization activities are presented for the Apache Leap Tuff field site. The field site is located in unsaturated, fractured tuff in central Arizona. Hydraulic, pneumatic, and thermal characteristics of the tuff are summarized, along with methodologies employed to monitor and sample hydrologic and geochemical processes at the field site. Thermohydrologic experiments are reported which provide laboratory and field data related to the effects conditions and flow and transport in unsaturated, fractured rock. 29 refs., 17 figs., 21 tabs.

Evans, D.D.; Rasmussen, T.C. [Arizona Univ., Tucson, AZ (USA). Dept. of Hydrology and Water Resources

1991-01-01T23:59:59.000Z

110

An integrated methodology for characterizing flow and transport processes in fractured rock  

E-Print Network (OSTI)

Unsaturated Zone, Yucca Mountain, Nevada. Water-Resourcesof the unsaturated zone of Yucca Mountain, NV from three-in fractured tuffs of Yucca Mountain, Vadose Zone Journal,

Wu, Yu-Shu

2007-01-01T23:59:59.000Z

111

On the relationship between stress and elastic strain for porous and fractured rock  

E-Print Network (OSTI)

of pressure on electrical resistivity of rocks. J Geophysproperties are electrical resistivity/conductivity dataof pressure on the electrical resistivity of water-saturated

Liu, Hui-Hai

2009-01-01T23:59:59.000Z

112

On the Relationship between Stress and Elastic Strain for Porous and Fractured Rock  

E-Print Network (OSTI)

and Orange, A. S. , Electrical resistivity in saturated rockof pressure on electrical resistivity of rocks, J. Geophys.of pressure on the electrical resistivity of water-saturated

Berryman, Hui-Hai Liu, Jonny Rutqvist and James G.

2009-01-01T23:59:59.000Z

113

Tectonic Setting and Characteristics of Natural Fractures in Mesaverde and Dakota Reservoirs of the San Juan Basin, New Mexico and Colorado  

SciTech Connect

A set of vertical extension fractures, striking N-S to NNE-SSW but with local variations, is present in both the outcrop and subsurface in both Mesaverde and Dakota sandstones. Additional sets of conjugate shear fractures have been recognized in outcrops of Dakota strata and may be present in the subsurface. However, the deformation bands prevalent locally in outcrops in parts of the basin as yet have no documented subsurface equivalent. The immature Mesaverde sandstones typically contain relatively long, irregular extension fractures, whereas the quartzitic Dakota sandstones contain short, sub-parallel, closely spaced, extension fractures, and locally conjugate shear planes as well. Outcrops typically display secondary cross fractures which are rare in the subsurface, although oblique fractures associated with local structures such as the Hogback monocline may be present in similar subsurface structures. Spacings of the bed-normal extension fractures are approximately equal to or less than the thicknesses of the beds in which they formed, in both outcrop and subsurface. Fracture intensities increase in association with faults, where there is a gradation from intense fracturing into fault breccia. Bioturbation and minimal cementation locally inhibited fracture development in both formations, and the vertical limits of fracture growth are typically at bedding/lithology contrasts. Fracture mineralizations have been largely dissolved or replaced in outcrops, but local examples of preserved mineralization show that the quartz and calcite common to subsurface fractures were originally present in outcrop fractures. North-south trending compressive stresses created by southward indentation of the San Juan dome area (where Precambrian rocks are exposed at an elevation of 14,000 ft) and northward indentation of the Zuni uplift, controlled Laramide-age fracturing. Contemporaneous right-lateral transpressive wrench motion due to northeastward translation of the basin was both concentrated at the basin margins (Nacimiento uplift and Hogback monocline on east and west edges respectively) and distributed across the strata depth.

LORENZ, JOHN C.; COOPER, SCOTT P.

2001-01-01T23:59:59.000Z

114

Determination of in-situ stress to predict direction of hydraulically created fractures for development of hot dry rock geothermal reservoir in Japan  

DOE Green Energy (OSTI)

It is very important to know the underground stress state to design and complete a Hot Dry Rock geothermal reservoir because the direction of the hydraulic fractures depends on the earth stress. The hydraulic mini fracturing technique was introduced to determine the in-situ stress state without assuming the borehole axis to be parallel to one of the principal stresses. Small scale hydraulic fracturing tests were conducted to verify this technique at an underground power plant and microseismic activities were monitored for fracture mapping. The direction of the fracture propagation was estimated from the in-situ stress state and compared with the fracture plane mapped by microseismic activities. 2 refs., 7 figs., 1 tab.

Kuriyagawa, Michio; Kobayashi, Hideo; Matsunaga, Isao; Kosugi, Masayuki; Yamaguchi, Tsutomu; Sasaki, Shunji; Hori, Yoshinao

1985-01-01T23:59:59.000Z

115

A discrete fracture model for a hot dry rock geothermal reservoir  

DOE Green Energy (OSTI)

Modeling results are presented for the Fenton Hill Phase II reservoir using a two-dimensional steady state simulator of fluid flow and solute transport in fractured porous media. Fluid flow and tracer response data are simulated using a fracture flow model in which the fracture apertures are string functions of pressure. The model is used to match the available steady state data of pressure drop versus flow rate and the tracer data. Various schemes for improving reservoir performance, such as high backpressure, chemical etching, stimulation using a viscous fluid, and the drilling of a second production wellbore, are then examined. 15 refs., 7 figs., 4 tabs.

Robinson, B.A.

1989-01-01T23:59:59.000Z

116

Proceedings of the Second International Symposium on Dynamics of Fluids in Fractured Rock  

E-Print Network (OSTI)

hydrothermal flow at Yucca Mountain, Part I: Modeling andScale Heater Test at Yucca Mountain. Eleventh Annual V.M.for fracture sealing at Yucca Mountain, Nevada. Journal of

Faybishenko, Boris; Witherspoon, Paul A.

2004-01-01T23:59:59.000Z

117

On Two-Phase Relative Permeability and Capillary Pressure of Rough-Walled Rock Fractures  

E-Print Network (OSTI)

range of conditions multiphase flows in porous media can befor describing multiphase flow in porous media. Given themultiphase flow is in petroleum reservoirs, many of which are situated in fractured-porous

Pruess ed, K.; Tsang, Y.W.

1989-01-01T23:59:59.000Z

118

Proceedings of the Second International Symposium on Dynamics of Fluids in Fractured Rock  

E-Print Network (OSTI)

Fractured Media A. Fourno, C. Grenier, F. Delay, E. Mouche,Time Predictive Models C. Grenier, A. Fourno , , E. Mouche,André Fourno 1,2 , Christophe Grenier 1 , Frederic Delay 3

Faybishenko, Boris; Witherspoon, Paul A.

2004-01-01T23:59:59.000Z

119

3D Modeling of Coupled Rock Deformation and Thermo-Poro-Mechanical Processes in Fractures  

E-Print Network (OSTI)

Problems involving coupled thermo-poro-chemo-mechanical processes are of great importance in geothermal and petroleum reservoir systems. In particular, economic power production from enhanced geothermal systems, effective water-flooding of petroleum reservoirs, and stimulation of gas shale reservoirs are significantly influenced by coupled processes. During such procedures, stress state in the reservoir is changed due to variation in pore fluid pressure and temperature. This can cause deformation and failure of weak planes of the formation with creation of new fractures, which impacts reservoir response. Incorporation of geomechanical factor into engineering analyses using fully coupled geomechanics-reservoir flow modeling exhibits computational challenges and numerical difficulties. In this study, we develop and apply efficient numerical models to solve 3D injection/extraction geomechanics problems formulated within the framework of thermo-poro-mechanical theory with reactive flow. The models rely on combining Displacement Discontinuity (DD) Boundary Element Method (BEM) and Finite Element Method (FEM) to solve the governing equations of thermo-poro-mechanical processes involving fracture/reservoir matrix. The integration of BEM and FEM is accomplished through direct and iterative procedures. In each case, the numerical algorithms are tested against a series of analytical solutions. 3D study of fluid injection and extraction into the geothermal reservoir illustrates that thermo-poro-mechanical processes change fracture aperture (fracture conductivity) significantly and influence the fluid flow. Simulations that consider joint stiffness heterogeneity show development of non-uniform flow paths within the crack. Undersaturated fluid injection causes large silica mass dissolution and increases fracture aperture while supersaturated fluid causes mineral precipitation and closes fracture aperture. Results show that for common reservoir and injection conditions, the impact of fully developed thermoelastic effect on fracture aperture tend to be greater compare to that of poroelastic effect. Poroelastic study of hydraulic fracturing demonstrates that large pore pressure increase especially during multiple hydraulic fracture creation causes effective tensile stress at the fracture surface and shear failure around the main fracture. Finally, a hybrid BEFEM model is developed to analyze stress redistribution in the overburden and within the reservoir during fluid injection and production. Numerical results show that fluid injection leads to reservoir dilation and induces vertical deformation, particularly near the injection well. However, fluid withdrawal causes reservoir to compact. The Mandel-Cryer effect is also successfully captured in numerical simulations, i.e., pore pressure increase/decrease is non-monotonic with a short time values that are above/below the background pore pressure.

Rawal, Chakra

2012-05-01T23:59:59.000Z

120

Enhancing in situ bioremediation with pneumatic fracturing  

Science Conference Proceedings (OSTI)

A major technical obstacle affecting the application of in situ bioremediation is the effective distribution of nutrients to the subsurface media. Pneumatic fracturing can increase the permeability of subsurface formations through the injection of high pressure air to create horizontal fracture planes, thus enhancing macro-scale mass-transfer processes. Pneumatic fracturing technology was demonstrated at two field sites at Tinker Air Force Base, Oklahoma City, Oklahoma. Tests were performed to increase the permeability for more effective bioventing, and evaluated the potential to increase permeability and recovery of free product in low permeability soils consisting of fine grain silts, clays, and sedimentary rock. Pneumatic fracturing significantly improved formation permeability by enhancing secondary permeability and by promoting removal of excess soil moisture from the unsaturated zone. Postfracture airflows were 500% to 1,700% higher than prefracture airflows for specific fractured intervals in the formation. This corresponds to an average prefracturing permeability of 0.017 Darcy, increasing to an average of 0.32 Darcy after fracturing. Pneumatic fracturing also increased free-product recovery rates of number 2 fuel from an average of 587 L (155 gal) per month before fracturing to 1,647 L (435 gal) per month after fracturing.

Anderson, D.B.; Peyton, B.M.; Liskowitz, J.L.; Fitzgerald, C.; Schuring, J.R.

1994-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Proceedings of the workshop on numerical modeling of thermohydrological flow in fractured rock masses  

DOE Green Energy (OSTI)

Nineteen papers were presented at the workshop on modeling thermohydrologic flow in fractured masses. This workshop was a result of the interest currently being given to the isolation of nuclear wastes in geologic formations. Included in these proceedings are eighteen of the presentations, one abstract and summaries of the panel discussions. The papers are listed under the following categories: introduction; overviews; fracture modelings; repository studies; geothermal models; and recent developments. Eighteen of the papers have been abstracted and indexed.

Not Available

1980-09-01T23:59:59.000Z

122

Fracture Permeability Evolution in Rock from the Desert Peak EGS Site  

DOE Green Energy (OSTI)

Fluid flow experiments are being conducted on core specimens of quartz monzonite retrieved from depths of about 1 km at the Desert Peak East EGS site in Churchill County, Nevada. Our immediate goal is to observe permeability evolution in fractures at pressure and temperature conditions appropriate to the Desert Peak geothermal site. Longer term, we aim to evaluate mechanisms that control the evolution of fracture permeability. In the experiments saline water is flowed through an artificial fracture at a constant rate of 0.02 ml/min over a period of several weeks. The constant flow tests are interrupted at selected times for shorter tests in which flow is either stopped or varied between 0 and 2.0 ml/min. The experiments to date were conducted at a confining pressure of 5.5 MPa, pore pressures of 1.38 MPa or 2.07 MPa and temperatures of 167- 169 C. Measurements include differential pressure and electrical resistance across the specimen. The short-term variable flow rate experiments allow us to calculate the effective hydraulic aperture of the fracture at various times during the experiment. Changes in electrical resistivity provide indirect evidence of ongoing mineral dissolution and precipitation processes that are expected to change fracture permeability over time. The early experiments have shown that electrical resistivity rises during flow and falls during intervals in which flow is stopped.

Carlson, S R; Roberts, J J; Detwiler, R L; Burton, E A; Robertson-Tait, A; Morris, C; Kasameyer, P

2004-04-08T23:59:59.000Z

123

Preferential flow paths and heat pipes: Results from laboratory experiments on heat-driven flow in natural and artificial rock fractures  

SciTech Connect

Water flow in fractures under the conditions of partial saturation and thermal drive may lead to fast flow along preferential localized pathways and heat pipe conditions. Water flowing in fast pathways may ultimately contact waste packages at Yucca Mountain and transport radionuclides to the accessible environment. Sixteen experiments were conducted to visualize liquid flow in glass fracture models, a transparent epoxy fracture replica, and a rock/replica fracture assembly. Spatially resolved thermal monitoring was performed in seven of these experiments to evaluate heat-pipe formation. Depending on the fracture apertures and flow conditions, various flow regimes were observed including continuous rivulet flow for high flow rates, intermittent rivulet flow and drop flow for intermediate flow rates, and film flow for low flow rates and wide apertures. These flow regimes were present in both fracture models and in the replica of a natural fracture. Heat-pipe conditions indicated by low thermal gradients were observed in five experiments. Conditions conducive to heat-pipe formation include an evaporation zone, condensation zone, adequate space for vapor and liquid to travel, and appropriate fluid driving forces. In one of the two experiments where heat pipe conditions were not observed, adequate space for liquid-vapor counterflow was not provided. Heat pipe conditions were not established in the other, because liquid flow was inadequate to compensate for imbibition and the quantity of heat contained within the rock.

Kneafsey, T.J.; Pruess, K. [Lawrence Berkeley National Lab., CA (United States). Earth Sciences Div.

1997-06-01T23:59:59.000Z

124

Two-phase flow in regionally saturated fractured rock near excavations  

Science Conference Proceedings (OSTI)

Hydrologic characterization for potential nuclear waste repositories relies upon data obtained from testing in excavations. The Simulated Drift Experiment in the Stripa Mine in Sweden, a fractured granitic formation below the water table, investigated excavation effects on hydrologic response. Measured water inflow to the drift at atmospheric pressure was nine times less than the value predicted from the inflow to boreholes with pressure held at 2.7 bars. This flow reduction may be due to dissolved gas that comes out of solution at pressures below 2.7 bars, creating a two-phase regime. To investigate this possibility, theoretical studies of flow through fractures when the water is super-saturated with respect to dissolved gas are carried out, using a simple analytical solution followed by a numerical model which relaxes some of the simplifying assumptions. Laboratory experiments that simulate degassing in transparent fracture replicas are conducted to test the assumptions used in the theoretical studies.

Geller, J.T.; Doughty, C.; Long, J.C.S. [Lawrence Berkeley Lab., CA (United States). Earth Sciences Div.

1994-11-01T23:59:59.000Z

125

Rock matrix and fracture analysis of flow in western tight gas sands: 1986 annual report  

SciTech Connect

This report presents progress for the second year of a five-year project concerned with the pore structure and flow properties of low permeability gas sands. The main objective of work during the first year was to carry out advanced core analysis on cores recovered from the Multi-Well Field Experiment. In Phase 2, the properties of both fractured and non-fractured samples (hereafter referred to as matrix) have been studied. Special attention was given to the combined effect of overburden pressure and water saturation on gas flow. 11 refs., 18 figs., 4 tabs.

Morrow, N.R.; Buckley, J.S.; Cather, S.M.; Brower, K.R.; Dandge, V.; Graham, M.; Gonzales, B.

1987-02-01T23:59:59.000Z

126

Coupled gas flow/solid dynamics model for predicting the formation of fracture patterns in gas well simulation experiments. [Propellant mixture used instead of explosives to fracture rock surrounding borehole  

DOE Green Energy (OSTI)

A two-dimensional finite element model for predicting fracture patterns obtained in high energy gas fracture experiments is presented. In these experiments, a mixture of propellants is used instead of explosives to fracture the rock surrounding the borehole. The propellant mixture is chosen to tailor the pressure pulse so that multiple fractures emanate from the borehole. The model allows the fracture pattern and pressure pulse to be calculated for different combinations of propellant mixture, in situ stress conditions, and rock properties. The model calculates the amount of gas generated by the burning propellants using a burn rate given by a power law in pressure. By assuming that the gas behaves as a perfect gas and that the flow down the fractures is isothermal, the loss of gas from the borehole due to flow down the cracks is accounted for. The flow of gas down the cracks is included in an approximate manner by assuming self-similar pressure profiles along the fractures. Numerical examples are presented and compared to three different full-scale experiments. Results show a good correlation with the experimental data over a wide variety of test parameters. 9 reference, 10 figures, 3 tables.

Taylor, L.M.; Swenson, D.V.; Cooper, P.W.

1984-07-01T23:59:59.000Z

127

Reservoir Fracturing in the Geysers Hydrothermal System: Fact or Fallacy?  

DOE Green Energy (OSTI)

Proper application of proven worldwide fracture determination analyses adequately aids in the detection and enhanced exploitation of reservoir fractures in The Geysers steam field. Obsolete, superficial ideas concerning fracturing in this resource have guided various malformed judgements of the actual elusive trends. Utilizing regional/local tectonics with theoretical rack mechanics and drilling statistics, offers the most favorable method of fracture comprehension. Exploitation philosophies should favor lateral drilling trends along local tensional components and under specific profound drainage/faulting manifestations to enhance high productivities. Drill core observations demonstrate various degrees of fracture filling, brecciation, strain responses, and rock fracture properties, giving the most favorable impression of subsurface reservoir conditions. Considerably more work utilizing current fracturing principles and geologic thought is required to adequately comprehend and economically exploit this huge complex resource.

Hebein, Jeffrey J.

1986-01-21T23:59:59.000Z

128

Analysis of Thermally Induced Changes in Fractured Rock Permeability during Eight Years of Heating and Cooling at the Yucca Mountain Drift Scale Test  

SciTech Connect

We analyzed a data set of thermally induced changes in fractured rock permeability during a four-year heating (up to 200 C) and subsequent four-year cooling of a large volume, partially saturated and highly fractured volcanic tuff at the Yucca Mountain Drift Scale Test, in Nevada, USA. Permeability estimates were derived from about 700 pneumatic (air-injection) tests, taken periodically at 44 packed-off borehole intervals during the heating and cooling cycle from November 1997 through November 2005. We analyzed air-permeability data by numerical modeling of thermally induced stress and moisture movements and their impact on air permeability within the highly fractured rock. Our analysis shows that changes in air permeability during the initial four-year heating period, which were limited to about one order of magnitude, were caused by the combined effects of thermal-mechanically-induced stress on fracture aperture and thermal-hydrologically-induced changes in fracture moisture content. At the end of the subsequent four-year cooling period, air-permeability decreases (to as low as 0.2 of initial) and increases (to as high as 1.8 of initial) were observed. By comparison to the calculated thermo-hydro-elastic model results, we identified these remaining increases or decreases in air permeability as irreversible changes in intrinsic fracture permeability, consistent with either inelastic fracture shear dilation (where permeability increased) or inelastic fracture surface asperity shortening (where permeability decreased). In this paper, we discuss the possibility that such fracture asperity shortening and associated decrease in fracture permeability might be enhanced by dissolution of highly stressed surface asperities over years of elevated stress and temperature.

Rutqvist, J.; Freifeld, B.; Min, K.-B.; Elsworth, D.; Tsang, Y.

2008-06-01T23:59:59.000Z

129

THE STATE OF THE ART OF NUMERICAL MODELING OF THERMOHYDROLOGIC FLOW IN FRACTURED ROCK MASSES  

E-Print Network (OSTI)

with a constant bulk heat capacity CH = p m c m ) for thec ] at' w w r r where p c is the heat capacity of fluid andp c is the heat capacity of the rock. (c) at {; j [~pU

Wang, J.S.Y.

2013-01-01T23:59:59.000Z

130

Advanced Characterization of Fractured Reservoirs in Carbonate Rocks: The Michigan Basin  

SciTech Connect

The purpose of the study was to collect and analyze existing data on the Michigan Basin for fracture patterns on scales ranging form thin section to basin. The data acquisition phase has been successfully concluded with the compilation of several large digital databases containing nearly all the existing information on formation tops, lithology and hydrocarbon production over the entire Michigan Basin. These databases represent the cumulative result of over 80 years of drilling and exploration.

Wood, James R.; Harrison, William B.

2002-12-02T23:59:59.000Z

131

Surface and subsurface fault and fracture systems with associated natural gas production in the Lower Mississippian and Upper Devonian, Price Formation, southern West Virginia.  

E-Print Network (OSTI)

??Production from natural gas deposits is often enhanced by fault and fracture systems associated with reservoirs. This study presents analyses of fault and fracture systems… (more)

Johnson, S. Reed.

2007-01-01T23:59:59.000Z

132

A Mountain-Scale Thermal Hydrologic Model for Simulating Fluid Flow and Heat Transfer in Unsaturated Fractured Rock  

E-Print Network (OSTI)

for Modeling Fluid and Heat Flow in Fractured Porous Media,with fluid and heat flow in fractured porous media arefluid and heat flow in porous media, heat pipe, reservoir simulation, fractured

Wu, Yu-Shu; Mukhopadhyay, Sumit; Zhang, Keni; Bodvarsson, Gudmundur S.

2005-01-01T23:59:59.000Z

133

Analyzing flow patterns in unsaturated fractured rock of YuccaMountain using an integrated modeling approach  

SciTech Connect

This paper presents a series of modeling investigations to characterize percolation patterns in the unsaturated zone of Yucca Mountain, Nevada, a proposed underground repository site for storing high-level radioactive waste. The investigations are conducted using a modeling approach that integrates a wide variety of moisture, pneumatic, thermal, and isotopic geochemical field data into a comprehensive three-dimensional numerical model through model calibration. This integrated modeling approach, based on a dual-continuum formulation, takes into account the coupled processes of fluid and heat flow and chemical isotopic transport in Yucca Mountain's highly heterogeneous, unsaturated fractured tuffs. In particular, the model results are examined against different types of field-measured data and used to evaluate different hydrogeological conceptual models and their effects on flow patterns in the unsaturated zone. The objective of this work to provide understanding of percolation patterns and flow behavior through the unsaturated zone, which is a crucial issue in assessing repository performance.

Wu, Yu-Shu; Lu, Guoping; Zhang, Keni; Pan, Lehua; Bodvarsson,Gudmundur S.

2003-11-03T23:59:59.000Z

134

An Integrated Modeling Analysis of Unsaturated Flow Patterns inFractured Rock  

Science Conference Proceedings (OSTI)

Characterizing percolation patterns in unsaturated zones hasposed a greater challenge to numerical modeling investigations thancomparable saturated zone studies, because of the heterogeneous nature ofunsaturated media as well as the great number of variables impactingunsaturated zone flow. This paper presents an integrated modelingmethodology for quantitatively characterizing percolation patterns in theunsaturated zone of Yucca Mountain, Nevada, a proposed undergroundrepository site for storing high-level radioactive waste. It takes intoaccount the multiple coupled processes of air, water, heat flow andchemical isotopic transport in Yucca Mountain s highly heterogeneous,unsaturated fractured tuffs. The modeling approach integrates a widevariety of moisture, pneumatic, thermal, and isotopic geochemical fielddata into a comprehensive three-dimensional numerical model for modelinganalyses. Modeling results are examined against different types offield-measured data and then used to evaluate different hydrogeologicalconceptual models and their results of flow patterns in the unsaturatedzone. In particular, this integration model provides a much clearerunderstanding of percolation patterns and flow behavior through theunsaturated zone, both crucial issues in assessing repositoryperformance. The integrated approach for quantifying Yucca Mountain sflow system is also demonstrated to provide a comprehensive modeling toolfor characterizing flow and transport processes in complex subsurfacesystems.

Wu, Yu-Shu; Lu, Guoping; Zhang, Keni; Pan, Lehua; Bodvarsson,Gudmundur S.

2005-03-21T23:59:59.000Z

135

ADVANCED CHARACTERIZATION OF FRACTURED RESERVOIRS IN CARBONATE ROCKS: THE MICHIGAN BASIN  

SciTech Connect

Among the accomplishments of this past reporting period are obtaining a complete landgrid for the State of Michigan and the digital processing of the high and medium resolution DEM files. We can now extract lineations from the DEMs automatically using machine algorithms. One tentative result that may be very significant is that we may be seeing manifestations of buried structures in the DEM data. We are looking at a set of extracted lineations in the northern lower peninsula that appear to follow the trend of the pinnacle reefs (Silurian) which had relief approaching 300 feet but are now buried to greater than 3000 feet. We have also extracted the dolomite alteration data from all fields and can show that this is mainly confined to the basin center. It may be related to the paleo-rift suggested by the paleomagnetic and gravity data. As reported last time, the acquisition of a 3D seismic dataset over Stoney Point Field from Marathon Oil Company, is complete and attention is being devoted to incorporating the data into the project database and utilizing it. The surface lineation study is focusing on Stoney Point Field using the high-resolution DEM data and plotting of subsurface formation top data for the main reservoir, the Trenton (Ordovician) Formation. The fault pattern at Stoney Point is well documented by Marathon and we are looking for any manifestations on the surface. The main project database is now about as complete as it will be for this project. The main goals have been met, although the scanning of the paper records will have to continue beyond the scheduled end of the project due to the sheer number of records and the increased donations of data from companies as word spread of the project. One of the unanticipated benefits of the project has been the cooperation of gas and oil companies that are or were active in the Michigan Basin in donating material to the project. Both Michigan Tech and Western Michigan continue to receive donations at an accelerating pace. The data management software developed to handle the data, Atlas, is scheduled to undergo a 3rd revision before the project ends. The goals are to streamline access to the data by improving the display and add several new features, including the ability to turn the landgrid on and off. We may also be able to include the capability to calculate or recalculate footage calls as well. We discovered the reason that some of the 1/24,000 USGS DEM (Digital Elevation Models) for the State of Michigan contain high levels of noise and are making one last attempt to acquire a set of good files before the project ends. This will greatly improve the large-scale map (48 inches x 84 inches) that has been constructed by mosaicking of the high-resolution files. This map shows excellent ground surface detail and has drawn much comment and requests for copies at the venues where it has been displayed. Although it was generated for mapping of surface lineations the map has other uses, particularly analysis of the glacial drift in Michigan.

James R. Wood; William B. Harrison

2001-04-01T23:59:59.000Z

136

Hydraulic Fracturing in Particulate Materials .  

E-Print Network (OSTI)

??For more than five decades, hydraulic fracturing has been widely used to enhance oil and gas production. Hydraulic fracturing in solid materials (e.g., rock) has… (more)

Chang, Hong

2004-01-01T23:59:59.000Z

137

ADVANCED TECHNOLOGY FOR PREDICTING THE FLUID FLOW ATTRIBUTES OF NATURALLY FRACTURED RESERVOIRS FROM QUANTITATIVE GEOLOGIC DATA AND MODELING  

Science Conference Proceedings (OSTI)

This report summarizes the work carried out during the period of September 29, 2000 to January 15, 2004 under DOE Research Contract No. DE-FC26-00BC15308. High temperatures and reactive fluids in sedimentary basins dictate that interplay and feedback between mechanical and geochemical processes significantly influence evolving rock and fracture properties. Not only does diagenetic mineralization fill in once open fractures either partially or completely, it modifies the rock mechanics properties that can control the mechanical aperture of natural fractures. In this study, we have evolved an integrated methodology of fractured reservoir characterization and we have demonstrated how it can be incorporated into fluid flow simulation. The research encompassed a wide range of work from geological characterization methods to rock mechanics analysis to reservoir simulation. With regard to the characterization of mineral infilling of natural fractures, the strong interplay between diagenetic and mechanical processes is documented and shown to be of vital importance to the behavior of many types of fractured reservoirs. Although most recent literature emphasizes Earth stress orientation, cementation in fractures is likely a critically important control on porosity, fluid flow attributes, and even sensitivity to effective stress changes. The diagenetic processes of dissolution and partial cementation are key controls on the creation and distribution of open natural fractures within hydrocarbon reservoirs. The continuity of fracture-porosity is fundamental to how fractures conduct fluids. In this study, we have made a number of important discoveries regarding fundamental properties of fractures, in particular related to the prevalence of kinematically significant structures (crack-seal texture) within otherwise porous, opening-mode fractures, and the presence of an aperture size threshold below which fractures are completely filled and above which porosity is preserved. These observations can be linked to models of quartz cementation. Significant progress has been made as well in theoretical fracture mechanics and geomechanical modeling, allowing prediction of spatial distributions of fractures that mimic patterns observed in nature. Geomechanical modeling shows the spatial arrangement of opening mode fractures (joints and veins) is controlled by the subcritical fracture index of the material. In particular, we have been able to identify mechanisms that control the clustering of fractures in slightly deformed rocks. Fracture mechanics testing of a wide range of clastic rocks shows that the subcritical index is sensitive to diagenetic factors. We show geomechanical simulations of fracture aperture development can be linked to diagenetic models, modifying fracture porosity as fractures grow, and affect the dynamics of fracture propagation. Fluid flow simulation of representative fracture pattern realizations shows how integrated modeling can give new insight into permeability assessment in the subsurface. Using realistic, geomechanically generated fracture patterns, we propose a methodology for permeability estimation in nonpercolating networks.

Jon E. Olson; Larry W. Lake; Steve E. Laubach

2004-11-01T23:59:59.000Z

138

Hot Dry Rock; Geothermal Energy  

SciTech Connect

The commercial utilization of geothermal energy forms the basis of the largest renewable energy industry in the world. More than 5000 Mw of electrical power are currently in production from approximately 210 plants and 10 000 Mw thermal are used in direct use processes. The majority of these systems are located in the well defined geothermal generally associated with crustal plate boundaries or hot spots. The essential requirements of high subsurface temperature with huge volumes of exploitable fluids, coupled to environmental and market factors, limit the choice of suitable sites significantly. The Hot Dry Rock (HDR) concept at any depth originally offered a dream of unlimited expansion for the geothermal industry by relaxing the location constraints by drilling deep enough to reach adequate temperatures. Now, after 20 years intensive work by international teams and expenditures of more than $250 million, it is vital to review the position of HDR in relation to the established geothermal industry. The HDR resource is merely a body of rock at elevated temperatures with insufficient fluids in place to enable the heat to be extracted without the need for injection wells. All of the major field experiments in HDR have shown that the natural fracture systems form the heat transfer surfaces and that it is these fractures that must be for geothermal systems producing from naturally fractured formations provide a basis for directing the forthcoming but, equally, they require accepting significant location constraints on HDR for the time being. This paper presents a model HDR system designed for commercial operations in the UK and uses production data from hydrothermal systems in Japan and the USA to demonstrate the reservoir performance requirements for viable operations. It is shown that these characteristics are not likely to be achieved in host rocks without stimulation processes. However, the long term goal of artificial geothermal systems developed by systematic engineering procedures at depth may still be attained if high temperature sites with extensive fracturing are developed or exploited. [DJE -2005

1990-01-01T23:59:59.000Z

139

Seismological investigation of crack formation in hydraulic rock fracturing experiments and in natural geothermal environments. Progress report, September 1, 1980-August 31, 1981  

DOE Green Energy (OSTI)

Progress is reported on the following: interpretation of seismic data from hydraulic fracturing experiments at the Fenton Hill Hot Dry Rock Geothermal Site, interpretation of 3-D velocity anomalies in the western US with special attention to geothermal areas, theoretical and observational studies of scattering and attenuation of high-frequency seismic waves, theoretical and observational studies of volcanic tremors in relation to magma transport mechanisms, and deployment and maintenance of 9 event-recorders around Mt. St. Helens. Abstracts of papers submitted for publication are included. (MHR)

Aki, K.

1981-09-01T23:59:59.000Z

140

Chemical Signatures of and Precursors to Fractures Using Fluid Inclusion Stratigraphy  

Science Conference Proceedings (OSTI)

Enhanced Geothermal Systems (EGS) are designed to recover heat from the subsurface by mechanically creating fractures in subsurface rocks. Open or recently closed fractures would be more susceptible to enhancing the permeability of the system. Identifying dense fracture areas as well as large open fractures from small fracture systems will assist in fracture stimulation site selection. Geothermal systems are constantly generating fractures (Moore, Morrow et al. 1987), and fluids and gases passing through rocks in these systems leave small fluid and gas samples trapped in healed microfractures. These fluid inclusions are faithful records of pore fluid chemistry. Fluid inclusions trapped in minerals as the fractures heal are characteristic of the fluids that formed them, and this signature can be seen in fluid inclusion gas analysis. This report presents the results of the project to determine fracture locations by the chemical signatures from gas analysis of fluid inclusions. With this project we hope to test our assumptions that gas chemistry can distinguish if the fractures are open and bearing production fluids or represent prior active fractures and whether there are chemical signs of open fracture systems in the wall rock above the fracture. Fluid Inclusion Stratigraphy (FIS) is a method developed for the geothermal industry which applies the mass quantification of fluid inclusion gas data from drill cuttings and applying known gas ratios and compositions to determine depth profiles of fluid barriers in a modern geothermal system (Dilley, 2009; Dilley et al., 2005; Norman et al., 2005). Identifying key gas signatures associated with fractures for isolating geothermal fluid production is the latest advancement in the application of FIS to geothermal systems (Dilley and Norman, 2005; Dilley and Norman, 2007). Our hypothesis is that peaks in FIS data are related to location of fractures. Previous work (DOE Grant DE-FG36-06GO16057) has indicated differences in the chemical signature of fluid inclusions between open and closed fractures as well as differences in the chemical signature of open fractures between geothermal systems. Our hypothesis is that open fracture systems can be identified by their FIS chemical signature; that there are differences based on the mineral assemblages and geology of the system; and that there are chemical precursors in the wall rock above open, large fractures. Specific goals for this project are: (1) To build on the preliminary results which indicate that there are differences in the FIS signatures between open and closed fractures by identifying which chemical species indicate open fractures in both active geothermal systems and in hot, dry rock; (2) To evaluate the FIS signatures based on the geology of the fields; (3) To evaluate the FIS signatures based on the mineral assemblages in the fracture; and (4) To determine if there are specific chemical signatures in the wall rock above open, large fractures. This method promises to lower the cost of geothermal energy production in several ways. Knowledge of productive fractures in the boreholes will allow engineers to optimize well production. This information can aid in well testing decisions, well completion strategies, and in resource calculations. It will assist in determining the areas for future fracture enhancement. This will develop into one of the techniques in the 'tool bag' for creating and managing Enhanced Geothermal Systems.

Lorie M. Dilley

2011-03-30T23:59:59.000Z

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Proceedings of the Workshop on Numerical Modeling of Thermohydrological Flow in Fractured Rock Masses, Feb. 19-20, 1980, Berkeley, CA  

E-Print Network (OSTI)

governing fluid flow through fractured porous media consistSIMULATION OF FLUID FLOW IN FRACTURED POROUS MEDIA T . N .ABSTRACT Fluid flow in fractured porous media can be

Witherspoon, P.A.

2010-01-01T23:59:59.000Z

142

Stress control of seismicity patterns observed during hydraulic fracturing experiments at the Fenton Hill hot dry rock geothermal energy site, New Mexico  

DOE Green Energy (OSTI)

Seismicity accompanying hydraulic injections into granitic rock is often diffuse rather than falling along a single plane. This diffuse zone of seismicity cannot be attributed to systematic errors in locations of the events. It has often been asserted that seismicity occurs along preexisting joints in the rock that are favorably aligned with the stress field so that slip can occur along them when effective stress is reduced by increasing pore fluid pressure. A new scheme for determining orientations and locations of planes along which the microearthquakes occurred was recently developed. The basic assumption of the method, called the three point method, is that many of the events fall along well defined planes; these planes are often difficult to identify visually in the data because planes of many orientations are present. The method has been applied to four hydraulic fracturing experiments conducted at Fenton Hill as part of a hot dry rock geothermal energy project. While multiple planes are found for each experiment; one plane is common to all experiments. The ratio of shear to normal stress along planes of all orientations is calculated using a best estimate of the current stress state at Fenton Hill. The plane common to all experiments has the highest ratio of shear to normal stress acting along it, so it is the plane most likely to slip. The other planes found by the three point method all have orientations with respect to current principal stresses that are favorable for slip to occur along preexisting planes of weakness. These results are consistent with the assertion that the rock contains pre-existing joints which slip when the effective stress is reduced by the increased pore fluid pressure accompanying the hydraulic injection. Microearthquakes occur along those planes that are favorably aligned with respect to the current stress field.

Fehler, M.C.

1987-04-13T23:59:59.000Z

143

Self-potential observations during hydraulic fracturing  

E-Print Network (OSTI)

and T. W. Keech (1977), Hydraulic fracture mapping usingpotential measurements during hydraulic fracturing of Bunterbetween electrical and hydraulic flow patterns from rock

Moore, J R; Glaser, Steven D

2007-01-01T23:59:59.000Z

144

Autonomous microexplosives subsurface tracing system final report.  

SciTech Connect

The objective of the autonomous micro-explosive subsurface tracing system is to image the location and geometry of hydraulically induced fractures in subsurface petroleum reservoirs. This system is based on the insertion of a swarm of autonomous micro-explosive packages during the fracturing process, with subsequent triggering of the energetic material to create an array of micro-seismic sources that can be detected and analyzed using existing seismic receiver arrays and analysis software. The project included investigations of energetic mixtures, triggering systems, package size and shape, and seismic output. Given the current absence of any technology capable of such high resolution mapping of subsurface structures, this technology has the potential for major impact on petroleum industry, which spends approximately $1 billion dollar per year on hydraulic fracturing operations in the United States alone.

Engler, Bruce Phillip; Nogan, John; Melof, Brian Matthew; Uhl, James Eugene; Dulleck, George R., Jr.; Ingram, Brian V.; Grubelich, Mark Charles; Rivas, Raul R.; Cooper, Paul W.; Warpinski, Norman Raymond; Kravitz, Stanley H.

2004-04-01T23:59:59.000Z

145

EA-1331: Remediation of Subsurface and Groundwater Contamination at the  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

331: Remediation of Subsurface and Groundwater Contamination at 331: Remediation of Subsurface and Groundwater Contamination at the Rock Springs in situ Oil Shale Retort Site, Sweetwater County, Wyoming EA-1331: Remediation of Subsurface and Groundwater Contamination at the Rock Springs in situ Oil Shale Retort Site, Sweetwater County, Wyoming SUMMARY This EA evaluates the environmental impacts for the proposal for the Rock Springs In-Situ Oil Shale Retort Test Site remediation that would be performed at the Rock Springs site in Sweetwater County, Wyoming. PUBLIC COMMENT OPPORTUNITIES None available at this time. DOCUMENTS AVAILABLE FOR DOWNLOAD July 31, 2000 EA-1331: Finding of No Significant Impact Remediation of Subsurface and Groundwater Contamination at the Rock Springs in situ Oil Shale Retort Site July 31, 2000 EA-1331: Final Environmental Assessment

146

Field study of tracer and geochemistry behavior during hydraulic fracturing of a hot dry rock geothermal reservoir  

DOE Green Energy (OSTI)

This study presents tracer and geochemistry data from several hydraulic fracturing experiments at the Fenton Hill, NM, HDR geothermal reservoir. Tracers have been injected at various times during these tests: (1) initially, before any flow communication existed between the wells; (2) shortly after a flow connection was established; and (3) after the outlet flow had increased to its steady state value. An idealized flow model consisting of a combination of main fracture flow paths and fluid leakoff into secondary permeability explains the different tracer response curves for these cases, and allows us to predict the fracture volume of the main paths. The geochemistry during these experiments supports our previously developed models postulating the existence of a high concentration indigenous ''pore fluid.'' Also, the quartz and Na-K-Ca geothermometers have been used successfully to identify the temperatures and depths at which fluid traveled while in the reservoir. The quartz geothermometer is somewhat more reliable because at these high temperatures (about 250/sup 0/C) the injected fluid can come to equilibrium with quartz in the reservoir. The Na-K-Ca geothermometer relies on obtaining a sample of the indigenous pore fluid, and thus is somewhat susceptible to problems of dilution with the injection fluid. 14 refs., 6 figs., 1 tab.

Robinson, B.A.

1986-01-01T23:59:59.000Z

147

HYDRAULIC FRACTURING AND INDUCED SEISMICITY IN KANSAS  

E-Print Network (OSTI)

For some time the public has asked questions about seismic activity related to hydraulic fracturing and other oil-field related activities. In particular, there is concern that the energy that goes into the subsurface during hydraulic fracturing is sufficient to cause felt earthquakes. The following is a response to those questions. 1) Seismic activity that is related to human activities is generally referred to as “induced seismicity ” or “triggered seismicity. ” Induced seismicity is defined as “seismic events attributable to human activities ” (National Research Council, 2012). The term “triggered seismicity ” is also used to describe situations in which human activities “could potentially ‘trigger ’ large and potentially damaging earthquakes ” (Shemeta et al., 2012). The following discussion uses only the term “induced seismicity ” to refer to seismic activity in which human activity plays a role. 2) Because it uses energy to fracture rocks to release oil or natural gas, hydraulic fracturing does create microseismic events (of a magnitude less than 2.0). Felt earthquake activity (generally greater than a magnitude 3.0) resulting from hydraulic fracturing has been confirmed from only one location in the world (National Research Council, 2012). In the

unknown authors

2013-01-01T23:59:59.000Z

148

Establishing the Relationship between Fracture-Related Dolomite and Primary Rock Fabric on the Distribution of Reservoirs in the Michigan Basin  

SciTech Connect

This topical report covers the year 2 of the subject 3-year grant, evaluating the relationship between fracture-related dolomite and dolomite constrained by primary rock fabric in the 3 most prolific reservoir intervals in the Michigan Basin (Ordovician Trenton-Black River Formations; Silurian Niagara Group; and the Devonian Dundee Formation). The characterization of select dolomite reservoirs has been the major focus of our efforts in Phase II/Year 2. Fields have been prioritized based upon the availability of rock data for interpretation of depositional environments, fracture density and distribution as well as thin section, geochemical, and petrophysical analyses. Structural mapping and log analysis in the Dundee (Devonian) and Trenton/Black River (Ordovician) suggest a close spatial relationship among gross dolomite distribution and regional-scale, wrench fault related NW-SE and NE-SW structural trends. A high temperature origin for much of the dolomite in the 3 studied intervals (based upon initial fluid inclusion homogenization temperatures and stable isotopic analyses,) coupled with persistent association of this dolomite in reservoirs coincident with wrench fault-related features, is strong evidence for these reservoirs being influenced by hydrothermal dolomitization. For the Niagaran (Silurian), a comprehensive high resolution sequence stratigraphic framework has been developed for a pinnacle reef in the northern reef trend where we had 100% core coverage throughout the reef section. Major findings to date are that facies types, when analyzed at a detailed level, have direct links to reservoir porosity and permeability in these dolomites. This pattern is consistent with our original hypothesis of primary facies control on dolomitization and resulting reservoir quality at some level. The identification of distinct and predictable vertical stacking patterns within a hierarchical sequence and cycle framework provides a high degree of confidence at this point that results will be exportable throughout the basin. Ten petrophysically significant facies have been described in the northern reef trend, providing significantly more resolution than the standard 4-6 that are used most often in the basin (e.g. Gill, 1977). Initial petrophysical characterization (sonic velocity analysis under confining pressures) shows a clear pattern that is dependent upon facies and resulting pore architecture. Primary facies is a key factor in the ultimate diagenetic modification of the rock and the resulting pore architecture. Facies with good porosity and permeability clearly show relatively slow velocity values as would be expected, and low porosity and permeability samples exhibit fast sonic velocity values, again as expected. What is significant is that some facies that have high porosity values, either measured directly or from wireline logs, also have very fast sonic velocity values. This is due to these facies having a pore architecture characterized by more localized pores (vugs, molds or fractures) that are not in communication.

G. Michael Grammer

2006-09-30T23:59:59.000Z

149

Fold Catastrophe Model of Fracture Propagation of Hydraulic Fracturing  

Science Conference Proceedings (OSTI)

According to energy conservation from the destruction of rock catastrophe, a new calculation method of the length of fracture propagation in hydraulic fracturing is proposed, and assuming the crack extends to approximate ellipse, the width calculation ... Keywords: hydraulic fracture, fold catastrophe, fracture parameters

Zhaowan Chun; Wan Tingting; Ai Chi; Ju Guoshuai

2010-05-01T23:59:59.000Z

150

Proceedings of hot dry rock geothermal workshop  

DOE Green Energy (OSTI)

Abstracts of 38 papers are included on the following subjects: rock mechanics, part 1: hydraulic fracturing; fracture imaging and borehole surveying; fluid flow-pressure analyses; rock mechanics, part 2: hydraulic fracturing and thermal cracking; geochemistry; heat extraction modeling; and economics and energy conversion. (MHR)

Elsner, D.B. (comp.)

1978-09-01T23:59:59.000Z

151

NFFLOW: A reservoir simulator incorporating explicit fractures (SPE 153890)  

SciTech Connect

NFFLOW is a research code that quickly and inexpensively simulates flow in moderately fractured reservoirs. It explicitly recognizes fractures separately from rock matrix. In NFFLOW fracture flow is proportional to the pressure gradient along the fracture, and flow in the rock matrix is determined by Darcy’s Law. The two flow mechanisms are coupled through the pressure gradient between a fracture and its adjacent rock matrix. Presented is a promising change to NFFLOW that allows for flow across a rock matrix block.

Boyle, E.J.; Sams, W.N.

2012-01-01T23:59:59.000Z

152

Characterizing Fractures in Geysers Geothermal Field by Micro...  

Open Energy Info (EERE)

water through existing fractures into hot wet and hot dry rocks by thermo-elastic cooling shrinkage. The stimulated, existing fractures thus enhance the permeability of the...

153

Characterizing the Mechanics of Fracturing from Earthquake Source Parameter and Multiplet Analyses: Application to the Soultz-sous-Forêts Hot Dry Rock site  

E-Print Network (OSTI)

In 2000 and 2003, two massive hydraulic fracturing experiments were carried out at the European Geothermal Hot

Michelet, Sophie

2005-01-01T23:59:59.000Z

154

Geophysical characterization of subsurface barriers  

SciTech Connect

An option for controlling contaminant migration from plumes and buried waste sites is to construct a subsurface barrier of a low-permeability material. The successful application of subsurface barriers requires processes to verify the emplacement and effectiveness of barrier and to monitor the performance of a barrier after emplacement. Non destructive and remote sensing techniques, such as geophysical methods, are possible technologies to address these needs. The changes in mechanical, hydrologic and chemical properties associated with the emplacement of an engineered barrier will affect geophysical properties such a seismic velocity, electrical conductivity, and dielectric constant. Also, the barrier, once emplaced and interacting with the in situ geologic system, may affect the paths along which electrical current flows in the subsurface. These changes in properties and processes facilitate the detection and monitoring of the barrier. The approaches to characterizing and monitoring engineered barriers can be divided between (1) methods that directly image the barrier using the contrasts in physical properties between the barrier and the host soil or rock and (2) methods that reflect flow processes around or through the barrier. For example, seismic methods that delineate the changes in density and stiffness associated with the barrier represents a direct imaging method. Electrical self potential methods and flow probes based on heat flow methods represent techniques that can delineate the flow path or flow processes around and through a barrier.

Borns, D.J.

1995-08-01T23:59:59.000Z

155

Geomechanical Simulation of Fluid-Driven Fractures  

SciTech Connect

The project supported graduate students working on experimental and numerical modeling of rock fracture, with the following objectives: (a) perform laboratory testing of fluid-saturated rock; (b) develop predictive models for simulation of fracture; and (c) establish educational frameworks for geologic sequestration issues related to rock fracture. These objectives were achieved through (i) using a novel apparatus to produce faulting in a fluid-saturated rock; (ii) modeling fracture with a boundary element method; and (iii) developing curricula for training geoengineers in experimental mechanics, numerical modeling of fracture, and poroelasticity.

Makhnenko, R.; Nikolskiy, D.; Mogilevskaya, S.; Labuz, J.

2012-11-30T23:59:59.000Z

156

Optimization of Construction Discharge Rate and Proppant Slugs for Preventing Complex Fractures  

Science Conference Proceedings (OSTI)

For volcanic rock and fracture type reservoir, etc, steering fractures, branching fractures and their combined herringbone fractures are usually caused by hydraulic fracturing. The generation of these complex fractures is one of the crucial factors that ... Keywords: hydraulic fracturing, construction discharge rate, complex fractures, proppant slug, optimization

Dali Guo; Yang Lin; Yong Ji; Jiangwen Xu; Guobin Wang

2011-10-01T23:59:59.000Z

157

How can we use one fracture to locate another?  

E-Print Network (OSTI)

Hydraulic fracturing is an important tool that helps extract fluids from the subsurface. It is critical in applications ranging from enhanced oil recovery to geothermal energy pro-duction. As the goal of fracturing is to ...

Poliannikov, Oleg V.

2011-01-01T23:59:59.000Z

158

Fracture patterns in graywacke outcrops at The Geysers geothermal field  

DOE Green Energy (OSTI)

The Geysers geothermal field covers an area of more than 35,000 acres and represents one of the most significant steam fields in the world. The heterogeneous nature of the reservoir, its fracture network and non-sedimentary rock distinguish it from ordinary sandstone reservoirs in terms of reservoir definition and evaluation (Stockton et al. 1984). Analysis of cuttings, record of steam entries, temperature and pressure surveys and spinner logs have contributed to an understanding of the subsurface geology and rock characteristics of the Geysers. Few conventional electrical log data are available for the main body of the reservoir. It is generally believed that while the fractures are the main conducts for fluid transport through the reservoirs, tight rocks between the major fractures contain the bulk of the fluid reserves. No independent measurement of liquid and vapor saturation can be made from the existing downhole tools. Pressure depletion in The Geysers geothermal field has become a major concern to the operators and utility companies in recent years. Plans for further development activities and future field management are contingent upon accurate computer modeling and definition of the field. The primary issues in reliable characterization of The Geysers field are the role of the rock matrix in holding liquid reserves and providing pressure support, the nature of fracture network, extent of liquid saturation in the reservoirs and injection pattern strategies to maximize heat recovery. Current modeling of The Geysers field is done through the use of general purpose geothermal reservoir simulators. Approaches employed include treating the reservoir as a single porosity equivalent or a dual porosity system. These simulators include formulation to represent transport of heat, steam and water. Heterogeneities are represented by spatial variations in formation or fracture permeability-thickness product, porosity or fluid saturations. Conceptual models based on dual porosity representations have been shown to duplicate the history. Prediction of future performance is, however, not reliable because of uncertainties in assumptions of the initial state of the reservoir, Specifically, several different initial state conditions have led to a fairly good match of the historical data. Selection of the exact initial conditions is a major dilemma. In dual porosity models, the complex nature of fracture network is formulated by a systematic, well-organized set of orthogonal fractures. Also, the exact nature of matrix-fracture interaction, and the role of adsorption and capillarity in pressure support are not well-defined.

Sammis, Charles G.; Lin Ji An; Ershaghi, I.

1991-01-01T23:59:59.000Z

159

Acoustic Character Of Hydraulic Fractures In Granite  

E-Print Network (OSTI)

Hydraulic fractures in homogeneous granitic rocks were logged with conventional acoustic-transit-time, acoustic-waveform, and acoustic-televiewer logging systems. Fractured intervals ranged in depth from 45 to 570m. and ...

Paillet, Frederick I.

1983-01-01T23:59:59.000Z

160

TEMPORAL VARIATIONS OF FRACTURE DIRECTIONS AND FRACTURE DENSITIES IN THE  

Open Energy Info (EERE)

TEMPORAL VARIATIONS OF FRACTURE DIRECTIONS AND FRACTURE DENSITIES IN THE TEMPORAL VARIATIONS OF FRACTURE DIRECTIONS AND FRACTURE DENSITIES IN THE COSO GEOTHERMAL FIELD FROM ANALYSES OF SHEAR-WAVE SPLITTING Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: TEMPORAL VARIATIONS OF FRACTURE DIRECTIONS AND FRACTURE DENSITIES IN THE COSO GEOTHERMAL FIELD FROM ANALYSES OF SHEAR-WAVE SPLITTING Details Activities (1) Areas (1) Regions (0) Abstract: This project aims to improve understanding of the subsurface fracture system in the Coso geothermal field, located in the east central California. We applied shear-wave splitting technique on a set of high quality, locally recorded microearthquake (MEQ) data. Four major fracture directions have been identified from the seismograms recorded by the permanent sixteen-station down-hole array: N10- 20W, NS, N20E, and N40-45E,

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161

Analysis of Thermally Induced Changes in Fractured Rock Permeability during Eight Years of Heating and Cooling at the Yucca Mountain Drift Scale Test  

E-Print Network (OSTI)

and Cooling at the Yucca Mountain Drift Scale Test J.mechanical analysis of the Yucca Mountain Drift Scale Test –scale heater test at Yucca Mountain, Nevada, USA. Int J Rock

Rutqvist, J.

2008-01-01T23:59:59.000Z

162

Subsurface Geotechnical Parameters Report  

Science Conference Proceedings (OSTI)

The Yucca Mountain Project is entering a the license application (LA) stage in its mission to develop the nation's first underground nuclear waste repository. After a number of years of gathering data related to site characterization, including activities ranging from laboratory and site investigations, to numerical modeling of processes associated with conditions to be encountered in the future repository, the Project is realigning its activities towards the License Application preparation. At the current stage, the major efforts are directed at translating the results of scientific investigations into sets of data needed to support the design, and to fulfill the licensing requirements and the repository design activities. This document addresses the program need to address specific technical questions so that an assessment can be made about the suitability and adequacy of data to license and construct a repository at the Yucca Mountain Site. In July 2002, the U.S. Nuclear Regulatory Commission (NRC) published an Integrated Issue Resolution Status Report (NRC 2002). Included in this report were the Repository Design and Thermal-Mechanical Effects (RDTME) Key Technical Issues (KTI). Geotechnical agreements were formulated to resolve a number of KTI subissues, in particular, RDTME KTIs 3.04, 3.05, 3.07, and 3.19 relate to the physical, thermal and mechanical properties of the host rock (NRC 2002, pp. 2.1.1-28, 2.1.7-10 to 2.1.7-21, A-17, A-18, and A-20). The purpose of the Subsurface Geotechnical Parameters Report is to present an accounting of current geotechnical information that will help resolve KTI subissues and some other project needs. The report analyzes and summarizes available qualified geotechnical data. It evaluates the sufficiency and quality of existing data to support engineering design and performance assessment. In addition, the corroborative data obtained from tests performed by a number of research organizations is presented to reinforce conclusions derived from the pool of data gathered within a full QA-controlled domain. An evaluation of the completeness of the current data is provided with respect to the requirements for geotechnical data to support design and performance assessment.

D. Rigby; M. Mrugala; G. Shideler; T. Davidsavor; J. Leem; D. Buesch; Y. Sun; D. Potyondy; M. Christianson

2003-12-17T23:59:59.000Z

163

Acord 1-26 hot, dry well, Roosevelt Hot Springs hot dry rock prospect, Utah  

DOE Green Energy (OSTI)

The Acord 1-26 well is a hot, dry well peripheral to the Roosevelt Hot Springs known geothermal resource area (KGRA) in southwestern Utah. The bottom-hole temperature in this 3854-m-deep well is 230/sup 0/C, and the thermal gradient is 54/sup 0/C/km. The basal 685 m, comprised of biotite monzonite and quartz schist and gneiss, is a likely hot, dry rock (HDR) prospect. The hole was drilled in a structural low within the Milford Valley graben and is separated from the Roosevelt KGRA to the east by the Opal Mound Fault and other basin faults. An interpretation of seismic data approximates the subsurface structure around the well using the lithology in the Acord 1-26 well. The hole was drilled with a minimum of difficulty, and casing was set to 2411 m. From drilling and geophysical logs, it is deduced that the subsurface blocks of crystalline rock in the vicinity of the Acord 1-26 well are tight, dry, shallow, impermeable, and very hot. A hydraulic fracture test of the crystalline rocks below 3170 m is recommended. Various downhole tools and techniques could be tested in promising HDR regimes within the Acord 1-26 well.

Shannon, S.S. Jr.; Pettitt, R.; Rowley, J.; Goff, F.; Mathews, M.; Jacobson, J.J.

1983-08-01T23:59:59.000Z

164

Electrical Subsurface Grounding Analysis  

SciTech Connect

The purpose and objective of this analysis is to determine the present grounding requirements of the Exploratory Studies Facility (ESF) subsurface electrical system and to verify that the actual grounding system and devices satisfy the requirements.

J.M. Calle

2000-11-01T23:59:59.000Z

165

Thickness Measurement of Fracture Fluid Gel Filter Cake after Static Build Up and Shear Erosion.  

E-Print Network (OSTI)

??The hydraulic fracturing treatment is an essential tight sand gas reservoir stimulation that employs viscous fluid to break the formation rock to create a fracture… (more)

Xu, Ben

2011-01-01T23:59:59.000Z

166

An overview of instability and fingering during immiscible fluid flow in porous and fractured media  

SciTech Connect

Wetting front instability is an important phenomenon affecting fluid flow and contaminant transport in unsaturated soils and rocks. It causes the development of fingers which travel faster than would a uniform front and thus bypass much of the medium. Water saturation and solute concentration in such fingers tend to be higher than in the surrounding medium. During infiltration, fingering may cause unexpectedly rapid arrival of water and solute at the water-table. This notwithstanding, most models of subsurface flow and transport ignore instability and fingering. In this report, we survey the literature to assess the extent to which this may or may not be justified. Our overview covers experiments, theoretical studies, and computer simulations of instability and fingering during immiscible two-phase flow and transport, with emphasis on infiltration into soils and fractured rocks. Our description of instability in an ideal fracture (Hele-Shaw cell) includes an extension of existing theory to fractures and interfaces having arbitrary orientations in space. Our discussion of instability in porous media includes a slight but important correction of existing theory for the case of an inclined interface. We conclude by outlining some potential directions for future research. Among these, we single out the effect of soil and rock heterogeneities on instability and preferential flow as meriting special attention in the context of nuclear waste storage in unsaturated media.

Chen, G.; Neuman, S.P. [Univ. of Arizona, Tucson, AZ (United States). Dept. of Hydrology and Water Resources; Taniguchi, M. [Nara Univ. of Education (Japan). Dept. of Earth Sciences

1995-04-01T23:59:59.000Z

167

Predicting the occurrence of open natural fractures in shale reservoirs  

SciTech Connect

Prolific oil and gas production has been established from naturally fractured shale reservoirs. For example, in the last few years over 4 Tcf of gas reserves have been established within the self-sourcing Antrim Shale of the Michigan Basin. Historically, locating subsurface fracture systems essential for commercial production has proven elusive and costly. An integrated exploration approach utilizing available geologic, geophysical, and remote sensing data has successfully located naturally fractured zones within the Antrim Shale. It is believed that fracturing of the Antrim shale was a result of basement involved tectonic processes. Characteristic integrated stacked signatures of known fracture systems within the Antrim were built using gravity and magnetic data, structure maps, fracture identification logs, and Landsat imagery. Wireline fracture logs pinpointed the locations and geometries of subsurface fracture systems. Landsat imagery was interpreted to reveal surficial manifestations of subsurface structures.

Decker, A.D.; Klawitter, A.L. (Advanced Resources International, Denver, CO (United States))

1996-01-01T23:59:59.000Z

168

Interaction between Injection Points during Hydraulic Fracturing  

E-Print Network (OSTI)

We present a model of the hydraulic fracturing of heterogeneous poroelastic media. The formalism is an effective continuum model that captures the coupled dynamics of the fluid pressure and the fractured rock matrix and models both the tensile and shear failure of the rock. As an application of the formalism, we study the geomechanical stress interaction between two injection points during hydraulic fracturing (hydrofracking) and how this interaction influences the fracturing process. For injection points that are separated by less than a critical correlation length, we find that the fracturing process around each point is strongly correlated with the position of the neighboring point. The magnitude of the correlation length depends on the degree of heterogeneity of the rock and is on the order of 30-45 m for rocks with low permeabilities. In the strongly correlated regime, we predict a novel effective fracture-force that attracts the fractures toward the neighboring injection point.

Hals, Kjetil M D

2012-01-01T23:59:59.000Z

169

Geomechanical Simulation of CO{sub 2} Leakage and Cap Rock Remediation  

SciTech Connect

CO{sub 2} sequestration into porous and permeable brine filled aquifers is seen as one of the most likely near-term solutions for reducing greenhouse gases. Safely storing injected CO{sub 2}, which is less dense than water, requires trapping the CO{sub 2} under an impermeable rock which would act as a seal. One of the concerns with CO{sub 2} sequestration is the generation of new fractures or reactivation of existing fractures and faults caused by CO{sub 2} injection into the sealing formation. Mitigation strategies must be developed to remediate potentially leaking faults or fractures. This project evaluated potential storage scenarios in the state of Missouri and developed coupled reservoir and geomechanic simulations to identify storage potential and leakage risks. Further, several injectable materials used to seal discontinuities were evaluated under subsurface conditions. The four sealant materials investigated were paraffin wax, silica based gel, polymer based gel, and micro-cement, which all significantly reduced the fracture permeability. However, the micro-cement was the most effective sealing agent and the only sealant able to withstand the large differential pressure caused by CO{sub 2} or brine injection and create a strong seal to prevent further fracturing.

Nygaard, Runar; Bai, Baojun; Eckert, Andreas

2012-09-30T23:59:59.000Z

170

Subsurface Contamination Control  

Science Conference Proceedings (OSTI)

There are two objectives of this report, ''Subsurface Contamination Control''. The first is to provide a technical basis for recommending limiting radioactive contamination levels (LRCL) on the external surfaces of waste packages (WP) for acceptance into the subsurface repository. The second is to provide an evaluation of the magnitude of potential releases from a defective WP and the detectability of the released contents. The technical basis for deriving LRCL has been established in ''Retrieval Equipment and Strategy for Wp on Pallet'' (CRWMS M and O 2000g, 6.3.1). This report updates the derivation by incorporating the latest design information of the subsurface repository for site recommendation. The derived LRCL on the external surface of WPs, therefore, supercede that described in CRWMS M and O 2000g. The derived LRCL represent the average concentrations of contamination on the external surfaces of each WP that must not be exceeded before the WP is to be transported to the subsurface facility for emplacement. The evaluation of potential releases is necessary to control the potential contamination of the subsurface repository and to detect prematurely failed WPs. The detection of failed WPs is required in order to provide reasonable assurance that the integrity of each WP is intact prior to MGR closure. An emplaced WP may become breached due to manufacturing defects or improper weld combined with failure to detect the defect, by corrosion, or by mechanical penetration due to accidents or rockfall conditions. The breached WP may release its gaseous and volatile radionuclide content to the subsurface environment and result in contaminating the subsurface facility. The scope of this analysis is limited to radioactive contaminants resulting from breached WPs during the preclosure period of the subsurface repository. This report: (1) documents a method for deriving LRCL on the external surfaces of WP for acceptance into the subsurface repository; (2) provides a table of derived LRCL for nuclides of radiological importance; (3) Provides an as low as is reasonably achievable (ALARA) evaluation of the derived LRCL by comparing potential onsite and offsite doses to documented ALARA requirements; (4) Provides a method for estimating potential releases from a defective WP; (5) Provides an evaluation of potential radioactive releases from a defective WP that may become airborne and result in contamination of the subsurface facility; and (6) Provides a preliminary analysis of the detectability of a potential WP leak to support the design of an airborne release monitoring system.

Y. Yuan

2001-12-12T23:59:59.000Z

171

Subsurface Contamination Control  

Science Conference Proceedings (OSTI)

There are two objectives of this report, ''Subsurface Contamination Control''. The first is to provide a technical basis for recommending limiting radioactive contamination levels (LRCL) on the external surfaces of waste packages (WP) for acceptance into the subsurface repository. The second is to provide an evaluation of the magnitude of potential releases from a defective WP and the detectability of the released contents. The technical basis for deriving LRCL has been established in ''Retrieval Equipment and Strategy for Wp on Pallet'' (CRWMS M and O 2000g, 6.3.1). This report updates the derivation by incorporating the latest design information of the subsurface repository for site recommendation. The derived LRCL on the external surface of WPs, therefore, supercede that described in CRWMS M and O 2000g. The derived LRCL represent the average concentrations of contamination on the external surfaces of each WP that must not be exceeded before the WP is to be transported to the subsurface facility for emplacement. The evaluation of potential releases is necessary to control the potential contamination of the subsurface repository and to detect prematurely failed WPs. The detection of failed WPs is required in order to provide reasonable assurance that the integrity of each WP is intact prior to MGR closure. An emplaced WP may become breached due to manufacturing defects or improper weld combined with failure to detect the defect, by corrosion, or by mechanical penetration due to accidents or rockfall conditions. The breached WP may release its gaseous and volatile radionuclide content to the subsurface environment and result in contaminating the subsurface facility. The scope of this analysis is limited to radioactive contaminants resulting from breached WPs during the preclosure period of the subsurface repository. This report: (1) documents a method for deriving LRCL on the external surfaces of WP for acceptance into the subsurface repository; (2) provides a table of derived LRCL for nuclides of radiological importance; (3) Provides an as low as is reasonably achievable (ALARA) evaluation of the derived LRCL by comparing potential onsite and offsite doses to documented ALARA requirements; (4) Provides a method for estimating potential releases from a defective WP; (5) Provides an evaluation of potential radioactive releases from a defective WP that may become airborne and result in contamination of the subsurface facility; and (6) Provides a preliminary analysis of the detectability of a potential WP leak to support the design of an airborne release monitoring system.

Y. Yuan

2001-11-16T23:59:59.000Z

172

Rock Lab Analysis | Open Energy Information  

Open Energy Info (EERE)

Rock Lab Analysis Rock Lab Analysis Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Rock Lab Analysis Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Lab Analysis Techniques Exploration Sub Group: Rock Lab Analysis Parent Exploration Technique: Lab Analysis Techniques Information Provided by Technique Lithology: Core and cuttings analysis is done to define lithology. Water rock interaction. Can determine detailed information about rock composition and morphology. Density of different lithologic units. Rapid and unambiguous identification of unknown minerals.[1] Stratigraphic/Structural: Core analysis can locate faults or fracture networks. Oriented core can give additional important information on anisotropy. Historic structure and deformation of land.

173

Response of Alum Rock springs to the October 30, 2007 Alum Rock earthquake and implications for the origin of increased discharge after earthquake  

Science Conference Proceedings (OSTI)

The origin of increased stream flow and spring discharge following earthquakes have been the subject of controversy, in large part because there are many models to explain observations and few measurements suitable for distinguishing between hypotheses. On October 30, 2007 a magnitude 5.5 earthquake occurred near the Alum Rock springs, California, USA. Within a day we documented a several-fold increase in discharge. Over the following year, we have monitored a gradual return towards pre-earthquake properties, but for the largest springs there appears to be a permanent increase in the steady discharge at all the springs. The Alum Rock springs discharge waters that represent a mixture between modern ('shallow') meteoric water and old ('deep') connate waters expelled by regional transpression. After the earthquake, the increased discharge at the largest springs was accompanied by a small decrease in the fraction of connate water in the spring discharge. Combined with the rapid response, this implies that the increased discharge has a shallow origin. Increased discharge at these springs occurs for earthquakes that cause static volumetric expansion and those that cause contraction, supporting models in which dynamic strains are responsible for the subsurface changes that cause flow to increase. We show that models in which the permeability of the fracture system feeding the springs increases after the earthquake are in general consistent with the changes in discharge. The response of these springs to another earthquake will provide critical constraints on the changes that occur in the subsurface.

Rowland, Joel C [Los Alamos National Laboratory; Manga, Michael [UC BERKELEY

2009-01-01T23:59:59.000Z

174

Mechanical and transport properties of rocks at high temperatures and pressures. Task I. The physical nature of fracturing at depth. Final report  

DOE Green Energy (OSTI)

The deformational behavior of granitic rocks is important to a wide variety of national and academic concerns. Both transient and steady state behavior at elevated temperature and pressure, in the presence and absence of excess H2O, have been investigated recently in solid pressure medium equipment and deformation mechanisms and empirical steady state flow laws have been determined. Efforts in the more precise gas and fluid pressure media apparatus have generally been concentrated on low pressure transient creep in order to evaluate effects of stress, temperature, pore pressure and, most recently, strain rate on failure times and static fatigue processes. Additional research is required and the stage is now set for a thorough physical understanding of the evolution from elastic-brittle, through transient (work-hardening)-semibrittle to steady-state-semibrittle to ductile flow of granitic rocks under both dry and wet (saline fluid pore pressure) conditions. 31 refs., 9 figs.

Carter, N.L.

1984-02-28T23:59:59.000Z

175

SUBSURFACE EMPLACEMENT TRANSPORTATION SYSTEM  

SciTech Connect

The objective of this analysis is to identify issues and criteria that apply to the design of the Subsurface Emplacement Transportation System (SET). The SET consists of the track used by the waste package handling equipment, the conductors and related equipment used to supply electrical power to that equipment, and the instrumentation and controls used to monitor and operate those track and power supply systems. Major considerations of this analysis include: (1) Operational life of the SET; (2) Geometric constraints on the track layout; (3) Operating loads on the track; (4) Environmentally induced loads on the track; (5) Power supply (electrification) requirements; and (6) Instrumentation and control requirements. This analysis will provide the basis for development of the system description document (SDD) for the SET. This analysis also defines the interfaces that need to be considered in the design of the SET. These interfaces include, but are not limited to, the following: (1) Waste handling building; (2) Monitored Geologic Repository (MGR) surface site layout; (3) Waste Emplacement System (WES); (4) Waste Retrieval System (WRS); (5) Ground Control System (GCS); (6) Ex-Container System (XCS); (7) Subsurface Electrical Distribution System (SED); (8) MGR Operations Monitoring and Control System (OMC); (9) Subsurface Facility System (SFS); (10) Subsurface Fire Protection System (SFR); (11) Performance Confirmation Emplacement Drift Monitoring System (PCM); and (12) Backfill Emplacement System (BES).

T. Wilson; R. Novotny

1999-11-22T23:59:59.000Z

176

Subsurface connection methods for subsurface heaters  

DOE Patents (OSTI)

A system for heating a subsurface formation is described. The system includes a first elongated heater in a first opening in the formation. The first elongated heater includes an exposed metal section in a portion of the first opening. The portion is below a layer of the formation to be heated. The exposed metal section is exposed to the formation. A second elongated heater is in a second opening in the formation. The second opening connects to the first opening at or near the portion of the first opening below the layer to be heated. At least a portion of an exposed metal section of the second elongated heater is electrically coupled to at least a portion of the exposed metal section of the first elongated heater in the portion of the first opening below the layer to be heated.

Vinegar, Harold J. (Bellaire, TX); Bass, Ronald Marshall (Houston, TX); Kim, Dong Sub (Sugar Land, TX); Mason, Stanley Leroy (Allen, TX); Stegemeier, George Leo (Houston, TX); Keltner, Thomas Joseph (Spring, TX); Carl, Jr., Frederick Gordon (Houston, TX)

2010-12-28T23:59:59.000Z

177

Fracture characterization of multilayered reservoirs  

Science Conference Proceedings (OSTI)

Fracture treatment optimization techniques have been developed using Long-Spaced-Digital-Sonic (LSDS) log, pumpin-flowback, mini-frac, and downhole treating pressure data. These analysis techniques have been successfully applied in massive hydraulic fracturing (MHF) of ''tight gas'' wells. Massive hydraulic fracture stimulations have been used to make many tight gas reservoirs commercially attractive. However, studies have shown that short highly conductive fractures are optimum for the successful stimulation of wells in moderate permeability reservoirs. As a result, the ability to design and place optimal fractures in these reservoirs is critical. This paper illustrates the application of fracture analysis techniques to a moderate permeability multi-layered reservoir. These techniques were used to identify large zonal variations in rock properties and pore pressure which result from the complex geology. The inclusion of geologic factors in fracture treatment design allowed the placement of short highly conductive fractures which were used to improve injectivity and vertical sweep, and therefore, ultimate recovery.

Britt, L.K.; Larsen, M.J.

1986-01-01T23:59:59.000Z

178

Analysis of fractures in volcanic cores from Pahute Mesa, Nevada Test Site  

SciTech Connect

The Nevada Test Site (NTS), located in Nye County, southern Nevada, was the location of 828 announced underground nuclear tests, conducted between 1951 and 1992. Approximately one-third of these tests were detonated near or below the water table. An unavoidable consequence of these testing activities was introducing radionuclides into the subsurface environment, impacting groundwater. Groundwater flows beneath the NTS almost exclusively through interconnected natural fractures in carbonate and volcanic rocks. Information about these fractures is necessary to determine hydrologic parameters for future Corrective Action Unit (CAU)-specific flow and transport models which will be used to support risk assessment calculations for the U.S. Department of Energy, Nevada Operations Office (DOE/NV) Underground Test Area (UGTA) remedial investigation. Fracture data are critical in reducing the uncertainty of the predictive capabilities of CAU-specific models because of their usefulness in generating hydraulic conductivity values and dispersion characteristics used in transport modeling. Specifically, fracture aperture and density (spacing) are needed to calculate the permeability anisotropy of the formations. Fracture mineralogy information is used qualitatively to evaluate diffusion and radionuclide retardation potential in transport modeling. All these data can best be collected through examination of core samples.

Drellack, S.L. Jr.; Prothro, L.B.; Roberson, K.E. [and others

1997-09-01T23:59:59.000Z

179

Fluid-rock interaction: A reactive transport approach  

SciTech Connect

Fluid-rock interaction (or water-rock interaction, as it was more commonly known) is a subject that has evolved considerably in its scope over the years. Initially its focus was primarily on interactions between subsurface fluids of various temperatures and mostly crystalline rocks, but the scope has broadened now to include fluid interaction with all forms of subsurface materials, whether they are unconsolidated or crystalline ('fluid-solid interaction' is perhaps less euphonious). Disciplines that previously carried their own distinct names, for example, basin diagenesis, early diagenesis, metamorphic petrology, reactive contaminant transport, chemical weathering, are now considered to fall under the broader rubric of fluid-rock interaction, although certainly some of the key research questions differ depending on the environment considered. Beyond the broadening of the environments considered in the study of fluid-rock interaction, the discipline has evolved in perhaps an even more important way. The study of water-rock interaction began by focusing on geochemical interactions in the absence of transport processes, although a few notable exceptions exist (Thompson 1959; Weare et al. 1976). Moreover, these analyses began by adopting a primarily thermodynamic approach, with the implicit or explicit assumption of equilibrium between the fluid and rock. As a result, these early models were fundamentally static rather than dynamic in nature. This all changed with the seminal papers by Helgeson and his co-workers (Helgeson 1968; Helgeson et al. 1969) wherein the concept of an irreversible reaction path was formally introduced into the geochemical literature. In addition to treating the reaction network as a dynamically evolving system, the Helgeson studies introduced an approach that allowed for the consideration of a multicomponent geochemical system, with multiple minerals and species appearing as both reactants and products, at least one of which could be irreversible. Helgeson's pioneering approach was given a more formal kinetic basis (including the introduction of real time rather than reaction progress as the independent variable) in subsequent studies (Lasaga 1981; Aagaard and Helgeson 1982; Lasaga 1984). The reaction path approach can be used to describe chemical processes in a batch or closed system (e.g., a laboratory beaker), but such systems are of limited interest in the Earth sciences where the driving force for most reactions is transport. Lichtner (1988) clarified the application of the reaction path models to water-rock interaction involving transport by demonstrating that they could be used to describe pure advective transport through porous media. By adopting a reference frame which followed the fluid packet as it moved through the medium, the reaction progress variable could be thought of as travel time instead. Multi-component reactive transport models that could treat any combination of transport and biogeochemical processes date back to the early 1980s. Berner and his students applied continuum reactive transport models to describe processes taking place during the early diagenesis of marine sediments (Berner 1980). Lichtner (1985) outlined much of the basic theory for a continuum model for multicomponent reactive transport. Yeh and Tripathi (1989) also presented the theoretical and numerical basis for the treatment of reactive contaminant transport. Steefel and Lasaga (1994) presented a reactive flow and transport model for nonisothermal, kinetically-controlled water-rock interaction and fracture sealing in hydrothermal systems based on simultaneous numerical solution of both reaction and transport This chapter begins with a review of the important transport processes that affect or even control fluid-rock interaction. This is followed by a general introduction to the governing equations for reactive transport, which are broadly applicable to both qualitative and quantitative interpretations of fluid-rock interactions. This framework is expanded through a discussion of specific topics that are the f

Steefel, C.; Maher, K.

2009-04-01T23:59:59.000Z

180

DETERMINATION OF MECHANICAL AND HYDRAULIC BEHAVIOR OF TENSILE FRACTURES UNDER MULTIPHASE FLOW USING X-RAY COMPUTED TOMOGRAPHY.  

E-Print Network (OSTI)

??Understanding fracture morphology in terms of a porous media is necessary for accurate simulation of multiphase transport in fractured rocks. Although ambient-stress methods for obtaining… (more)

Alvarado, Freddy

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Phase I (Year 1) Summary of Research--Establishing the Relationship between Fracture-Related Dolomite and Primary Rock Fabric on the Distribution of Reservoirs in the Michigan Basin  

Science Conference Proceedings (OSTI)

This topical report covers the first 12 months of the subject 3-year grant, evaluating the relationship between fracture-related dolomite and dolomite constrained by primary rock fabric in the 3 most prolific reservoir intervals in the Michigan Basin (Ordovician Trenton-Black River Formations; Silurian Niagara Group; and the Devonian Dundee Formation). Phase I tasks, including Developing a Reservoir Catalog for selected dolomite reservoirs in the Michigan Basin, Characterization of Dolomite Reservoirs in Representative Fields and Technology Transfer have all been initiated and progress is consistent with our original scheduling. The development of a reservoir catalog for the 3 subject formations in the Michigan Basin has been a primary focus of our efforts during Phase I. As part of this effort, we currently have scanned some 13,000 wireline logs, and compiled in excess of 940 key references and 275 reprints that cover reservoir aspects of the 3 intervals in the Michigan Basin. A summary evaluation of the data in these publications is currently ongoing, with the Silurian Niagara Group being handled as a first priority. In addition, full production and reservoir parameter data bases obtained from available data sources have been developed for the 3 intervals in Excel and Microsoft Access data bases. We currently have an excess of 25 million cells of data for wells in the Basin. All Task 2 objectives are on time and on target for Phase I per our original proposal. Our mapping efforts to date, which have focused in large part on the Devonian Dundee Formation, have important implications for both new exploration plays and improved enhanced recovery methods in the Dundee ''play'' in Michigan--i.e. the interpreted fracture-related dolomitization control on the distribution of hydrocarbon reservoirs. In an exploration context, high-resolution structure mapping using quality-controlled well data should provide leads to convergence zones of fault/fracture trends that are not necessarily related to structural elevation. Further work in Phase II will be focused on delineating the relative contribution to fracture-only dolomitization to that which occurs in conjunction with primary facies and/or sequence stratigraphic framework.

G. Michael Grammer

2005-11-09T23:59:59.000Z

182

Mechanical and transport properties of rocks at high temperatures and pressures. Task II. Fracture permeability of crystalline rocks as a function of temperature, pressure, and hydrothermal alteration. Final report  

DOE Green Energy (OSTI)

Pore-fluid chemical interactions on both short and long time scales can significantly change the permeability of a rock. Measurement of the permeability variations requires adaption and modification on standard measurement systems, with special attention given to pore-fluid flow rates and metal corrosion of system components. In this report, system requirements and capabilities are reviewed, analyzed, and recommendations made. Special attention is given to the choice of corrosion resistant metals, fluid-flow systems, back-pressure systems, jacketing materials, and flow-rate measurement. On the basis of this study, an economical, highly flexible, permeability system was designed and built. The system allows measurement of permeability over the darcy to nanodarcy range, using geologically meaningful, chemically reactive, pore fluids under constant volume flow rates as small as 0.2 ml/day at temperatures in excess of 300C, fluid pressures to 20 MPa, and confining pressures to 100 MPa. 7 refs., 3 figs., 1 tab.

Johnson, B.

1985-11-01T23:59:59.000Z

183

Use of Cutting-Edge Horizontal and Underbalanced Drilling Technologies and Subsurface Seismic Techniques to Explore, Drill and Produce Reservoired Oil and Gas from the Fractured Monterey Below 10,000 ft in the Santa Maria Basin of California  

Science Conference Proceedings (OSTI)

This project was undertaken to demonstrate that oil and gas can be drilled and produced safely and economically from a fractured Monterey reservoir in the Santa Maria Basin of California by employing horizontal wellbores and underbalanced drilling technologies. Two vertical wells were previously drilled in this area with heavy mud and conventional completions; neither was commercially productive. A new well was drilled by the project team in 2004 with the objective of accessing an extended length of oil-bearing, high-resistivity Monterey shale via a horizontal wellbore, while implementing managed-pressure drilling (MPD) techniques to avoid formation damage. Initial project meetings were conducted in October 2003. The team confirmed that the demonstration well would be completed open-hole to minimize productivity impairment. Following an overview of the geologic setting and local field experience, critical aspects of the application were identified. At the pre-spud meeting in January 2004, the final well design was confirmed and the well programming/service company requirements assigned. Various design elements were reduced in scope due to significant budgetary constraints. Major alterations to the original plan included: (1) a VSP seismic survey was delayed to a later phase; (2) a new (larger) surface hole would be drilled rather than re-enter an existing well; (3) a 7-in. liner would be placed into the top of the Monterey target as quickly as possible to avoid problems with hole stability; (4) evaluation activities were reduced in scope; (5) geosteering observations for fracture access would be deduced from penetration rate, cuttings description and hydrocarbon in-flow; and (6) rather than use nitrogen, a novel air-injection MPD system was to be implemented. Drilling operations, delayed from the original schedule by capital constraints and lack of rig availability, were conducted from September 12 to November 11, 2004. The vertical and upper curved sections were drilled and lined through the problematic shale member without major stability problems. The top of the targeted Monterey was thought to be seen at the expected TVD of 10,000 ft where the 7-in. liner was set at a 60{sup o} hole angle. Significant oil and gas shows suggested the fractured interval anticipated at the heel location had been penetrated. A total of 2572 ft of 6{Delta}-in. near-horizontal interval was placed in the shale section, extending planned well length by approximately 470 ft. Very little hydrocarbon in-flow was observed from fractures along the productive interval. This may be a result of the well trajectory falling underneath the Monterey fractured zone. Hydrocarbon observations, cuttings analysis and gamma-ray response indicated additional fractured intervals were accessed along the last {+-}900 ft of well length. The well was completed with a 2 and 7/8-in. tubing string set in a production packer in preparation for flow and swab tests to be conducted later by a service rig. The planned well time was estimated as 39 days and overall cost as $2.4 million. The actual results are 66 days at a total cost of $3.4 million. Well productivity responses during subsequent flow and swabbing tests were negative. The well failed to inflow and only minor amounts (a few barrels) of light oil were recovered. The lack of production may suggest that actual sustainable reservoir pressure is far less than anticipated. Temblor attempted in July, 2006, to re-enter and clean out the well and run an Array Induction log (primarily for resistivity and correlation purposes), and an FMI log (for fracture detection). Application of surfactant in the length of the horizontal hole, and acid over the fracture zone at 10,236 was also planned. This attempt was not successful in that the clean out tools became stuck and had to be abandoned.

George Witter; Robert Knoll; William Rehm; Thomas Williams

2006-06-30T23:59:59.000Z

184

Seismological investigation of crack formation in hydraulic rock fracturing experiments and in natural geothermal environments. Progress report, September 1, 1979-August 31, 1980  

DOE Green Energy (OSTI)

Progress is reported in the following research areas: a synthesis of seismic experiments at the Fenton Hill Hot-Dry-Rock System; attenuation of high-frequency shear waves in the lithosphere; a new kinematic source model for deep volcanic tremors; ground motion in the near-field of a fluid-driven crack and its interpretation in the study of shallow volcanic tremor; low-velocity bodies under geothermal areas; and operation of event recorders in Mt. St. Helens and Newberry Peak with preliminary results from them. (MHR)

Aki, K.

1980-09-01T23:59:59.000Z

185

USE OF CUTTING-EDGE HORIZONTAL AND UNDERBALANCED DRILLING TECHNOLOGIES AND SUBSURFACE SEISMIC TECHNIQUES TO EXPLORE, DRILL AND PRODUCE RESERVOIRED OIL AND GAS FROM THE FRACTURED MONTEREY BELOW 10,000 FT IN THE SANTA MARIA BASIN OF CALIFORNIA  

Science Conference Proceedings (OSTI)

This project was undertaken to demonstrate that oil and gas can be drilled and produced safely and economically from a fractured Monterey reservoir in the Santa Maria Basin of California by employing horizontal wellbores and underbalanced drilling technologies. Two vertical wells were previously drilled in this area by Temblor Petroleum with heavy mud and conventional completions; neither was commercially productive. A new well was drilled by the project team in 2004 with the objective of accessing an extended length of oil-bearing, high-resistivity Monterey shale via a horizontal wellbore, while implementing managed-pressure drilling (MPD) techniques to avoid formation damage. Initial project meetings were conducted in October 2003. The team confirmed that the demonstration well would be completed open-hole to minimize productivity impairment. Following an overview of the geologic setting and local field experience, critical aspects of the application were identified. At the pre-spud meeting in January 2004, the final well design was confirmed and the well programming/service company requirements assigned. Various design elements were reduced in scope due to significant budgetary constraints. Major alterations to the original plan included: (1) a VSP seismic survey was delayed to a later phase; (2) a new (larger) surface hole would be drilled rather than re-enter an existing well; (3) a 7-in. liner would be placed into the top of the Monterey target as quickly as possible to avoid problems with hole stability; (4) evaluation activities were reduced in scope; (5) geosteering observations for fracture access would be deduced from penetration rate, cuttings description and hydrocarbon in-flow; and (6) rather than use nitrogen, a novel air-injection MPD system was to be implemented. Drilling operations, delayed from the original schedule by capital constraints and lack of rig availability, were conducted from September 12 to November 11, 2004. The vertical and upper curved sections were drilled and lined through the problematic shale member without major stability problems. The top of the targeted Monterey was thought to be seen at the expected TVD of 10,000 ft where the 7-in. liner was set at a 60{sup o} hole angle. Significant oil and gas shows suggested the fractured interval anticipated at the heel location had been penetrated. A total of 2572 ft of 6.-in. near-horizontal interval was placed in the shale section, extending planned well length by approximately 470 ft. Very little hydrocarbon in-flow was observed from fractures along the productive interval. This may be a result of the well trajectory falling underneath the Monterey fractured zone. Hydrocarbon observations, cuttings analysis and gamma-ray response indicated additional fractured intervals were accessed along the last {+-}900 ft of well length. The well was completed with a 2 7/8-in. tubing string set in a production packer in preparation for flow and swab tests to be conducted later by a service rig. The planned well time was estimated as 39 days and overall cost as $2.4 million. The actual results are 66 days at a total cost of $3.4 million. Well productivity responses during subsequent flow and swabbing tests were negative. The well failed to inflow and only minor amounts (a few barrels) of light oil were recovered. The lack of production may suggest that actual sustainable reservoir pressure is far less than anticipated. Temblor is currently investigating the costs and operational viability of re-entering the well and conducting an FMI (fracture detection) log and/or an acid stimulation. No final decision or detailed plans have been made regarding these potential interventions at this time.

George Witter; Robert Knoll; William Rehm; Thomas Williams

2005-02-01T23:59:59.000Z

186

Use of Cutting-Edge Horizontal and Underbalanced Drilling Technologies and Subsurface Seismic Techniques to Explore, Drill and Produce Reservoired Oil and Gas from the Fractured Monterey Below 10,000 ft in the Santa Maria Basin of California  

Science Conference Proceedings (OSTI)

This project was undertaken to demonstrate that oil and gas can be drilled and produced safely and economically from a fractured Monterey reservoir in the Santa Maria Basin of California by employing horizontal wellbores and underbalanced drilling technologies. Two vertical wells were previously drilled in this area with heavy mud and conventional completions; neither was commercially productive. A new well was drilled by the project team in 2004 with the objective of accessing an extended length of oil-bearing, high-resistivity Monterey shale via a horizontal wellbore, while implementing managed-pressure drilling (MPD) techniques to avoid formation damage. Initial project meetings were conducted in October 2003. The team confirmed that the demonstration well would be completed open-hole to minimize productivity impairment. Following an overview of the geologic setting and local field experience, critical aspects of the application were identified. At the pre-spud meeting in January 2004, the final well design was confirmed and the well programming/service company requirements assigned. Various design elements were reduced in scope due to significant budgetary constraints. Major alterations to the original plan included: (1) a VSP seismic survey was delayed to a later phase; (2) a new (larger) surface hole would be drilled rather than re-enter an existing well; (3) a 7-in. liner would be placed into the top of the Monterey target as quickly as possible to avoid problems with hole stability; (4) evaluation activities were reduced in scope; (5) geosteering observations for fracture access would be deduced from penetration rate, cuttings description and hydrocarbon in-flow; and (6) rather than use nitrogen, a novel air-injection MPD system was to be implemented. Drilling operations, delayed from the original schedule by capital constraints and lack of rig availability, were conducted from September 12 to November 11, 2004. The vertical and upper curved sections were drilled and lined through the problematic shale member without major stability problems. The top of the targeted Monterey was thought to be seen at the expected TVD of 10,000 ft where the 7-in. liner was set at a 60{sup o} hole angle. Significant oil and gas shows suggested the fractured interval anticipated at the heel location had been penetrated. A total of 2572 ft of 6 1/8-in. near-horizontal interval was placed in the shale section, extending planned well length by approximately 470 ft. Very little hydrocarbon in-flow was observed from fractures along the productive interval. This may be a result of the well trajectory falling underneath the Monterey fractured zone. Hydrocarbon observations, cuttings analysis and gamma-ray response indicated additional fractured intervals were accessed along the last {+-}900 ft of well length. The well was completed with a 2 7/8-in. tubing string set in a production packer in preparation for flow and swab tests to be conducted later by a service rig. The planned well time was estimated as 39 days and overall cost as $2.4 million. The actual results are 66 days at a total cost of $3.4 million. Well productivity responses during subsequent flow and swabbing tests were negative. The well failed to inflow and only minor amounts (a few barrels) of light oil were recovered. The lack of production may suggest that actual sustainable reservoir pressure is far less than anticipated. Temblor is currently planning to re-enter and clean out the well and run an Array Induction log (primarily for resistivity and correlation purposes), and an FMI log (for fracture detection). Depending on the results of these logs, an acidizing or re-drill program will be planned.

George Witter; Robert Knoll; William Rehm; Thomas Williams

2005-09-29T23:59:59.000Z

187

Using electrical resistance tomography to map subsurface temperatures  

DOE Patents (OSTI)

A method is provided for measuring subsurface soil or rock temperatures remotely using electrical resistivity tomography (ERT). Electrical resistivity measurements are made using electrodes implanted in boreholes driven into the soil and/or at the ground surface. The measurements are repeated as some process changes the temperatures of the soil mass/rock mass. Tomographs of electrical resistivity are calculated based on the measurements using Poisson's equation. Changes in the soil/rock resistivity can be related to changes in soil/rock temperatures when: (1) the electrical conductivity of the fluid trapped in the soil's pore space is low, (2) the soil/rock has a high cation exchange capacity and (3) the temperature changes are sufficiently high. When these three conditions exist the resistivity changes observed in the ERT tomographs can be directly attributed to changes in soil/rock temperatures. This method provides a way of mapping temperature changes in subsurface soils remotely. Distances over which the ERT method can be used to monitor changes in soil temperature range from tens to hundreds of meters from the electrode locations.

Ramirez, Abelardo L. (Pleasanton, CA); Chesnut, Dwayne A. (San Francisco, CA); Daily, William D. (Livermore, CA)

1994-01-01T23:59:59.000Z

188

Using electrical resistance tomography to map subsurface temperatures  

DOE Patents (OSTI)

A method is provided for measuring subsurface soil or rock temperatures remotely using electrical resistivity tomography (ERT). Electrical resistivity measurements are made using electrodes implanted in boreholes driven into the soil and/or at the ground surface. The measurements are repeated as some process changes the temperatures of the soil mass/rock mass. Tomographs of electrical resistivity are calculated based on the measurements using Poisson's equation. Changes in the soil/rock resistivity can be related to changes in soil/rock temperatures when: (1) the electrical conductivity of the fluid trapped in the soil's pore space is low, (2) the soil/rock has a high cation exchange capacity and (3) the temperature changes are sufficiently high. When these three conditions exist the resistivity changes observed in the ERT tomographs can be directly attributed to changes in soil/rock temperatures. This method provides a way of mapping temperature changes in subsurface soils remotely. Distances over which the ERT method can be used to monitor changes in soil temperature range from tens to hundreds of meters from the electrode locations. 1 fig.

Ramirez, A.L.; Chesnut, D.A.; Daily, W.D.

1994-09-13T23:59:59.000Z

189

Seismological investigation of crack formation in hydraulic rock fracturing experiments and in natural geothermal environments. Progress report, September 1, 1978-August 31, 1979  

DOE Green Energy (OSTI)

An interpretation theory based on the fluid-filled crack model of geothermal systems is being developed and tested against a variety of data from various geothermal areas. Progress is reported on the following subjects: (1) analysis and interpretation of seismic data obtained from the bore holes at the LASL Hot Dry Rock geothermal site. (2) Collection, analysis and interpretation of data on deep volcanic tremors at the USGS Hawaii Volcano Observatory. (3) Development of a new method for determining seismic attenuation at frequencies higher than 1HZ, and initiation of a cooperative work with Mexican seismologists on the attenuation measurements at various geothermal areas in Baja, California using the method. (4) Installation of 3-component digital event-recorders at four stations in the Newberry Peak volcano, Oregon. (5) Developing a computer program for calculating seismic motion generated by the vibration of fluid-filled crack in a layered medium.

Aki, K.

1979-09-01T23:59:59.000Z

190

DOE hot dry rock program  

DOE Green Energy (OSTI)

Hydraulic fracturing has been used to create and subsequently to enlarge the first hot dry rock heat-extraction loop at Fenton Hill, New Mexico. Encouraging results prompted the DOE to expand this project into a program of national scope. The elements of that Program and their present status are discussed. Emphasis is given the ongoing Fenton Hill Project where techniques and information developed in the existing research system will soon be used to produce a multiply-fractured engineering system in hotter rock at the same site. Recent results from research loop operation and progress in constructing the engineering system are reported. Although acoustic mapping and system geometry indicate that the primary hydraulic fractures are essentially vertical, relatively low fracturing pressure and absence of a sharp breakdown suggest that at Fenton Hill fracture initiation occurs by reopening of old natural fractures rather than by initiation of new ones. Flow patterns and temperature behavior suggest opening of additional old fractures as the loop is operated. Except where the hot fluid leaves the crack system to enter the production well, flow impedances are very low without either artificial propping or inflation by pressurization.

Nunz, G.J.

1980-01-01T23:59:59.000Z

191

Application of the directional hydraulic fracturing at Berezovskaya Mine  

SciTech Connect

The paper analyzes the experimental research of the directional hydraulic fracturing applied for weakening of rocks at Berezovskaya Mine (Kuznetsk Coal Basin) in 2005-2006.

Lekontsev, Y.M.; Sazhin, P.V. [Russian Academy of Sciences, Novosibirsk (Russian Federation). Institute for Mining

2008-05-15T23:59:59.000Z

192

Variation in sericite composition from fracture zones within...  

Open Energy Info (EERE)

zones of the crystalline basement contain coarse-grained relict muscovite, whereas rock alteration near fracture zones at temperatures > 150C is characterized by abundant...

193

Magnetic induction technique for mapping vertical conductive fractures: theory of operation  

DOE Green Energy (OSTI)

Utilization of a hot dry rock geothermal resource requires circulation of a fluid (water) through fractures in the rock. The Los Alamos Scientific Laboratory is presently investigating the feasibility and economics of tapping this energy resource. Presently, the fractures in the rock are created by conventional hydraulic fracturing techniques. Accurate determination of the geometry of the fracture system is required so that boreholes may be drilled to complete the circulation system. The theory of a technique designed to map vertical conductive fractures located in resistive rock is presented. The technique is based on magnetic induction. Fracture thickness and strike can be determined from measurements made in a single borehole.

Not Available

1978-07-01T23:59:59.000Z

194

Nonisothermal injection tests in fractured reservoirs  

DOE Green Energy (OSTI)

The paper extends the analysis of nonisothermal pressure transient data to fractured reservoirs. Two cases are considered: reservoirs with predominantly horzontal fractures and reservoirs with predominantly vertical fractures. Effects of conductive heat transfer between the fractures and the rock matrix are modeled, and the resulting pressure transients evaluated. Thermal conduction tends to retard the movement of the thermal front in the fractures, which significantly affects the pressure transient data. The purpose of the numerical simulation studies is to provide methods for analyzing nonisothermal injection/falloff data for fractured reservoirs.

Cox, B.L.; Bodvarsson, G.S.

1985-01-01T23:59:59.000Z

195

Seismological investigation of crack formation in hydraulic rock fracturing experiments and in natural geothermal environments. Progress report, September 1, 1977--August 31, 1978  

DOE Green Energy (OSTI)

New seismological methods were developed for determining the structure of a geothermal energy source region by the use of data from both active and passive experiments. Technical papers were published on four topics, namely: a field experiment at Kilauea Iki, source models of volcanic tremors, microearthquake source spectra, and a numerical study of elastic wave diffraction by fluid-filled cracks. In addition, papers were submitted for publication on a statistical synthesis of source mechanism of seismic events in Kilauea Iki and the observation of a temporal variation in the attenuation of earthquake coda in central California. The following subjects were worked on: (1) interpretation of seismic data from the LASL Hot Dry Rock system; (2) analyisis of volcanic tremor data from the U.S.G.S. Hawaiian seismic network; (3) frequency dependence and three-dimensional distribution of seismic attenuation in central Japan; (4) experimental study of seismic scattering by a penny-shaped crack; (5) development of a microprocessor system for the treatment of the data from digital event recorders.

Aki, K.

1978-09-01T23:59:59.000Z

196

Numerical Investigation of Interaction Between Hydraulic Fractures and Natural Fractures  

E-Print Network (OSTI)

Hydraulic fracturing of a naturally-fractured reservoir is a challenge for industry, as fractures can have complex growth patterns when propagating in systems of natural fractures in the reservoir. Fracture propagation near a natural fracture (NF) considering interaction between a hydraulic fracture (HF) and a pre-existing NF, has been investigated comprehensively using a two dimensional Displacement Discontinuity Method (DDM) Model in this thesis. The rock is first considered as an elastic impermeable medium (with no leakoff), and then the effects of pore pressure change as a result of leakoff of fracturing fluid are considered. A uniform pressure fluid model and a Newtonian fluid flow model are used to calculate the fluid flow, fluid pressure and width distribution along the fracture. Joint elements are implemented to describe different NF contact modes (stick, slip, and open mode). The structural criterion is used for predicting the direction and mode of fracture propagation. The numerical model was used to first examine the mechanical response of the NF to predict potential reactivation of the NF and the resultant probable location for fracture re-initiation. Results demonstrate that: 1) Before the HF reaches a NF, the possibility of fracture re-initiation across the NF and with an offset is enhanced when the NF has weaker interfaces; 2) During the stage of fluid infiltration along the NF, a maximum tensile stress peak can be generated at the end of the opening zone along the NF ahead of the fluid front; 3) Poroelastic effects, arising from fluid diffusion into the rock deformation can induce closure and compressive stress at the center of the NF ahead of the HF tip before HF arrival. Upon coalescence when fluid flows along the NF, the poroelastic effects tend to reduce the value of the HF aperture and this decreases the tension peak and the possibility of fracture re-initiation with time. Next, HF trajectories near a NF were examined prior to coalesce with the NF using different joint, rock and fluid properties. Our analysis shows that: 1) Hydraulic fracture trajectories near a NF may bend and deviate from the direction of the maximum horizontal stress when using a joint model that includes initial joint deformation; 2) Hydraulic fractures propagating with higher injection rate or fracturing fluid of higher viscosity propagate longer distance when turning to the direction of maximum horizontal stress; 3) Fracture trajectories are less dependent on injection rate or fluid viscosity when using a joint model that includes initial joint deformation; whereas, they are more dominated by injection rate and fluid viscosity when using a joint model that excludes initial joint deformation.

Xue, Wenxu

2010-12-01T23:59:59.000Z

197

Microfractures in rocks from two geothermal areas | Open Energy Information  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Microfractures in rocks from two geothermal areas Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Microfractures in rocks from two geothermal areas Details Activities (2) Areas (2) Regions (0) Abstract: Core samples from the Dunes, California, and Raft River, Idaho, geothermal areas show diagenesis superimposed on episodic fracturing and fracture sealing. The minerals that fill fractures show significant temporal variations. Sealed fractures can act as barriers to fluid flow. Sealed fractures often mark boundaries between regions of significantly

198

GEOLOGY OF THE WILLISTON BASIN, NORTH DAKOTA, MONTANA, AND SOUTH DAKOTA, WITH REFERENCE TO SUBSURFACE DISPOSAL OF RADIOACTIVE WASTES  

SciTech Connect

The southern Williston basin, which underlies about 110,000 square miles in Nonth Dakota, South Dakota, and eastern Montana, is part of a large structural and sedimentary basin. The sedimentary sequence that fills the basin has a maximum thickness of about 16,700 feet and rests on Precambrian metamorphic rocks at depths of 500to 13,900 feet below sea level. It contains rocks of every geologic system from Cambrian to Quaternary. Rocks of the Williston basin are gently folded and regional dips are 1 deg or less from the margins to the basin center. The most important mineral resource of the area is oil, which is produced predominantly from the Paleozoic carbonate sequence and largely on three of the major anticlinal folds, and lignite, which is present near the surface in Paleocene rocks. The subsurface disposal of radioactive wastes at some places in the Williston basis appears to be geographically and geologically feasible. Many sites, at which large quantities of wastes might be injected with minimal danger of contamination of fresh-water aquifers with oil-producing strata, are available. The strata and types of reservoirs that deserve primary consideration for waste disposal are the Winnipeg Formation of Middle Ordovician age as a deep salaquifer, the Permian to Jurassic salt beds as moderately deep units in which solution cavities might be created for storage, the thick Upper Cretaceous shale beds as shallow hydraulically fractured shale reservoirs, and the Newcastie Sandstone of Early Cretaceous age as a shallow shale-enclosed sandstone reservoir. (auth)

Sandberg, C.A.

1962-06-01T23:59:59.000Z

199

Simulated evolution of fractures and fracture networks subject to thermal cooling: A coupled discrete element and heat conduction model  

SciTech Connect

Advancement of EGS requires improved prediction of fracture development and growth during reservoir stimulation and long-term operation. This, in turn, requires better understanding of the dynamics of the strongly coupled thermo-hydro-mechanical (THM) processes within fractured rocks. We have developed a physically based rock deformation and fracture propagation simulator by using a quasi-static discrete element model (DEM) to model mechanical rock deformation and fracture propagation induced by thermal stress and fluid pressure changes. We also developed a network model to simulate fluid flow and heat transport in both fractures and porous rock. In this paper, we describe results of simulations in which the DEM model and network flow & heat transport model are coupled together to provide realistic simulation of the changes of apertures and permeability of fractures and fracture networks induced by thermal cooling and fluid pressure changes within fractures. Various processes, such as Stokes flow in low velocity pores, convection-dominated heat transport in fractures, heat exchange between fluid-filled fractures and solid rock, heat conduction through low-permeability matrices and associated mechanical deformations are all incorporated into the coupled model. The effects of confining stresses, developing thermal stress and injection pressure on the permeability evolution of fracture and fracture networks are systematically investigated. Results are summarized in terms of implications for the development and evolution of fracture distribution during hydrofracturing and thermal stimulation for EGS.

Huang, Hai; Plummer, Mitchell; Podgorney, Robert

2013-02-01T23:59:59.000Z

200

Subsurface Ventilation System Description Document  

Science Conference Proceedings (OSTI)

The Subsurface Ventilation System supports the construction and operation of the subsurface repository by providing air for personnel and equipment and temperature control for the underground areas. Although the system is located underground, some equipment and features may be housed or located above ground. The system ventilates the underground by providing ambient air from the surface throughout the subsurface development and emplacement areas. The system provides fresh air for a safe work environment and supports potential retrieval operations by ventilating and cooling emplacement drifts. The system maintains compliance within the limits established for approved air quality standards. The system maintains separate ventilation between the development and waste emplacement areas. The system shall remove a portion of the heat generated by the waste packages during preclosure to support thermal goals. The system provides temperature control by reducing drift temperature to support potential retrieval operations. The ventilation system has the capability to ventilate selected drifts during emplacement and retrieval operations. The Subsurface Facility System is the main interface with the Subsurface Ventilation System. The location of the ducting, seals, filters, fans, emplacement doors, regulators, and electronic controls are within the envelope created by the Ground Control System in the Subsurface Facility System. The Subsurface Ventilation System also interfaces with the Subsurface Electrical System for power, the Monitored Geologic Repository Operations Monitoring and Control System to ensure proper and safe operation, the Safeguards and Security System for access to the emplacement drifts, the Subsurface Fire Protection System for fire safety, the Emplacement Drift System for repository performance, and the Backfill Emplacement and Subsurface Excavation Systems to support ventilation needs.

Eric Loros

2001-07-25T23:59:59.000Z

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Subsurface Ventilation System Description Document  

Science Conference Proceedings (OSTI)

The Subsurface Ventilation System supports the construction and operation of the subsurface repository by providing air for personnel and equipment and temperature control for the underground areas. Although the system is located underground, some equipment and features may be housed or located above ground. The system ventilates the underground by providing ambient air from the surface throughout the subsurface development and emplacement areas. The system provides fresh air for a safe work environment and supports potential retrieval operations by ventilating and cooling emplacement drifts. The system maintains compliance within the limits established for approved air quality standards. The system maintains separate ventilation between the development and waste emplacement areas. The system shall remove a portion of the heat generated by the waste packages during preclosure to support thermal goals. The system provides temperature control by reducing drift temperature to support potential retrieval operations. The ventilation system has the capability to ventilate selected drifts during emplacement and retrieval operations. The Subsurface Facility System is the main interface with the Subsurface Ventilation System. The location of the ducting, seals, filters, fans, emplacement doors, regulators, and electronic controls are within the envelope created by the Ground Control System in the Subsurface Facility System. The Subsurface Ventilation System also interfaces with the Subsurface Electrical System for power, the Monitored Geologic Repository Operations Monitoring and Control System to ensure proper and safe operation, the Safeguards and Security System for access to the emplacement drifts, the Subsurface Fire Protection System for fire safety, the Emplacement Drift System for repository performance, and the Backfill Emplacement and Subsurface Excavation Systems to support ventilation needs.

NONE

2000-10-12T23:59:59.000Z

202

Hot rocks  

Science Conference Proceedings (OSTI)

Four kilometers down below the orange earth of Australia¿s Cooper Basin lies some of the hottest nonvolcanic rock in the world¿rock that the geothermal industry had never seriously considered using to make electricity. But next month Geodynamics, an ...

S. Upson

2009-01-01T23:59:59.000Z

203

INTEGRATED OUTCROP AND SUBSURFACE STUDIES OF THE INTERWELL ENVIRONMENT OF CARBONATE RESERVOIRS: CLEAR FORK (LEONARDIAN-AGE) RESERVOIRS, WEST TEXAS AND NEW MEXICO  

SciTech Connect

This is the final report of the project ''Integrated Outcrop and Subsurface Studies of the Interwell Environment of Carbonate Reservoirs: Clear Fork (Leonardian-Age) Reservoirs, West Texas and New Mexico'', Department of Energy contract no. DE-AC26-98BC15105 and is the third in a series of similar projects funded jointly by the U.S. Department of Energy and The University of Texas at Austin, Bureau of Economic Geology, Reservoir Characterization Research Laboratory for Carbonates. All three projects focus on the integration of outcrop and subsurface data for the purpose of developing improved methods for modeling petrophysical properties in the interwell environment. The first project, funded by contract no. DE-AC22-89BC14470, was a study of San Andres outcrops in the Algerita Escarpment, Guadalupe Mountains, Texas and New Mexico, and the Seminole San Andres reservoir, Permian Basin. This study established the basic concepts for constructing a reservoir model using sequence-stratigraphic principles and rock-fabric, petrophysical relationships. The second project, funded by contract no. DE-AC22-93BC14895, was a study of Grayburg outcrops in the Brokeoff Mountains, New Mexico, and the South Cowden Grayburg reservoir, Permian Basin. This study developed a sequence-stratigraphic succession for the Grayburg and improved methods for locating remaining hydrocarbons in carbonate ramp reservoirs. The current study is of the Clear Fork Group in Apache Canyon, Sierra Diablo Mountains, West Texas, and the South Wasson Clear Fork reservoir, Permian Basin. The focus was on scales of heterogeneity, imaging high- and low-permeability layers, and the impact of fractures on reservoir performance. In this study (1) the Clear Fork cycle stratigraphy is defined, (2) important scales of petrophysical variability are confirmed, (3) a unique rock-fabric, petrophysical relationship is defined, (4) a porosity method for correlating high-frequency cycles and defining rock-fabric flow layers is described, (5) Clear Fork fractures are described and geomechanical modeling of fractures is investigated, and (6) most importantly, new statistical methods are developed for scaleup of petrophysical properties from the core to the layer scale and for retaining stratigraphic layering in simulation models.

F. Jerry Lucia

2002-01-31T23:59:59.000Z

204

HYDRAULIC FRACTURING  

NLE Websites -- All DOE Office Websites (Extended Search)

HYDRAULIC FRACTURING In addition to the recovery processes featured in this series of drawings, hydraulic fracturing is included as an example of technologies that contribute to...

205

Proceedings of the second international symposium on rock fragmentation by blasting  

SciTech Connect

This is the second international meeting of researchers in rock fragmentation by blasting. The symposium continues the information exchange initiated at the previous conference and to determine relevant directions for future research on fracture and fragmentation of rock.

Fourney, W.L.; Dick, R.D. (Maryland Univ., College Park, MD (USA))

1987-01-01T23:59:59.000Z

206

Apparatus and method for monitoring underground fracturing  

DOE Patents (OSTI)

An apparatus and method for measuring deformation of a rock mass around the vicinity of a fracture, commonly induced by hydraulic fracturing is provided. To this end, a well is drilled offset from the proposed fracture region, if no existing well is present. Once the well is formed to a depth approximately equal or exceeding the depth of the proposed fracture, a plurality of inclinometers, for example tiltmeters, are inserted downhole in the well. The inclinometers are located both above and below the approximate depth of the proposed fracture. The plurality of inclinometers may be arranged on a wireline that may be retrieved from the downhole portion of the well and used again or, alternatively, the inclinometers may be cemented in place. In either event, the inclinometers are used to measure the deformation of the rock around the induced fracture. 13 figs.

Warpinski, N.R.; Steinfort, T.D.; Branagan, P.T.; Wilmer, R.H.

1999-08-10T23:59:59.000Z

207

Apparatus and method for monitoring underground fracturing  

DOE Patents (OSTI)

An apparatus and method for measuring deformation of a rock mass around the vicinity of a fracture, commonly induced by hydraulic fracturing is provided. To this end, a well is drilled offset from the proposed fracture region, if no existing well is present. Once the well is formed to a depth approximately equal or exceeding the depth of the proposed fracture, a plurality of inclinometers, for example tiltmeters, are inserted downhole in the well. The inclinometers are located both above and below the approximate depth of the proposed fracture. The plurality of inclinometers may be arranged on a wireline that may be retrieved from the downhole portion of the well and used again or, alternatively, the inclinometers may be cemented in place. In either event, the inclinometers are used to measure the deformation of the rock around the induced fracture.

Warpinski, Norman R. (Albuquerque, NM); Steinfort, Terry D. (Tijeras, NM); Branagan, Paul T. (Las Vegas, NV); Wilmer, Roy H. (Las Vegas, NV)

1999-08-10T23:59:59.000Z

208

Simulation of CO2 Sequestration at Rock Spring Uplift, Wyoming: Heterogeneity and Uncertainties in Storage Capacity, Injectivity and Leakage  

SciTech Connect

Many geological, geochemical, geomechanical and hydrogeological factors control CO{sub 2} storage in subsurface. Among them heterogeneity in saline aquifer can seriously influence design of injection wells, CO{sub 2} injection rate, CO{sub 2} plume migration, storage capacity, and potential leakage and risk assessment. This study applies indicator geostatistics, transition probability and Markov chain model at the Rock Springs Uplift, Wyoming generating facies-based heterogeneous fields for porosity and permeability in target saline aquifer (Pennsylvanian Weber sandstone) and surrounding rocks (Phosphoria, Madison and cap-rock Chugwater). A multiphase flow simulator FEHM is then used to model injection of CO{sub 2} into the target saline aquifer involving field-scale heterogeneity. The results reveal that (1) CO{sub 2} injection rates in different injection wells significantly change with local permeability distributions; (2) brine production rates in different pumping wells are also significantly impacted by the spatial heterogeneity in permeability; (3) liquid pressure evolution during and after CO{sub 2} injection in saline aquifer varies greatly for different realizations of random permeability fields, and this has potential important effects on hydraulic fracturing of the reservoir rock, reactivation of pre-existing faults and the integrity of the cap-rock; (4) CO{sub 2} storage capacity estimate for Rock Springs Uplift is 6614 {+-} 256 Mt at 95% confidence interval, which is about 36% of previous estimate based on homogeneous and isotropic storage formation; (5) density profiles show that the density of injected CO{sub 2} below 3 km is close to that of the ambient brine with given geothermal gradient and brine concentration, which indicates CO{sub 2} plume can sink to the deep before reaching thermal equilibrium with brine. Finally, we present uncertainty analysis of CO{sub 2} leakage into overlying formations due to heterogeneity in both the target saline aquifer and surrounding formations. This uncertainty in leakage will be used to feed into risk assessment modeling.

Deng, Hailin [Los Alamos National Laboratory; Dai, Zhenxue [Los Alamos National Laboratory; Jiao, Zunsheng [Wyoming State Geological Survey; Stauffer, Philip H. [Los Alamos National Laboratory; Surdam, Ronald C. [Wyoming State Geological Survey

2011-01-01T23:59:59.000Z

209

Six Science Secrets of the Subsurface  

Science Conference Proceedings (OSTI)

This article highlights recent fundamental scientific research on subsurface radionuclide migration.

Manke, Kristin L.; Wiley, Julie G.

2010-03-02T23:59:59.000Z

210

A New Definition on Fractal Porous Rock Damage Variable and Study on Evolution Characteristics of Porosity-permeability  

Science Conference Proceedings (OSTI)

Considered the fractal characteristic of rock with porosity structure, a rock damage variable which describes rock damage of the reservoir of fractal structure with hydraulic fracturing is defined, and this damage variable that describes the state of ... Keywords: hydraulic fracturing, damage variable, fractal, porosity pore structure, permeability evolving

Zhaowan Chun; Wang Tingting; Ai Chi; Sun Chengyan

2010-05-01T23:59:59.000Z

211

Downhole tool sniffs out fractures  

SciTech Connect

This article reports that a new tool has been designed and successfully tested that can designate which direction from a borehole a particular fracture is located. Albuquerque-based Sandia National Laboratories tested the new tool. The prototype was built by Southwest Research Institute of San Antonio. During field tests, the tool detected simulated fractures more than 30 ft away from a test borehole. It determines fracture direction by transmitting highly directional and powerful radar pulses in a known direction. The pulses last eight billionths of a second and their frequency spectrum range up to the VHF (very high frequency) band. Discontinuities in the rock interrupt and reflect radar signals so that a signal's return to the tool indicates the presence of fractures. The return signal's time delay translates into distance from the borehole. The transmitter and receiver rotate in place, permitting the tool to scan for fractures in all directions.

Not Available

1987-05-01T23:59:59.000Z

212

Multidisciplinary Imaging of Rock Properties in Carbonate Reservoirs for Flow-Unit Targeting  

SciTech Connect

During the period major accomplishments were in (1) characterization of facies and cyclicity in subsurface cores and in outcrop, (2) construction of a preliminary stratigraphic framework, (3) definition of rock fabrics, and (4) correlation of 3-D seismic data.

Ruppel, Stephen C.

2002-10-08T23:59:59.000Z

213

Regulation of Hydraulic Fracturing (or lack thereof)  

E-Print Network (OSTI)

: "subsurface emplacement of fluids by well injection." 42 U.S.C. § 300h(d)(1). #12;UIC Program Requirements, EPA has concluded that the injection of hydraulic fracturing fluids into [coalbed methane] wells poses Water Act The federal Safe Drinking Water Act prohibits "underground injection" that is not authorized

Boufadel, Michel

214

Review of potential subsurface permeable barrier emplacement and monitoring technologies  

SciTech Connect

This report focuses on subsurface permeable barrier technologies potentially applicable to existing waste disposal sites. This report describes candidate subsurface permeable barriers, methods for emplacing these barriers, and methods used to monitor the barrier performance. Two types of subsurface barrier systems are described: those that apply to contamination.in the unsaturated zone, and those that apply to groundwater and to mobile contamination near the groundwater table. These barriers may be emplaced either horizontally or vertically depending on waste and site characteristics. Materials for creating permeable subsurface barriers are emplaced using one of three basic methods: injection, in situ mechanical mixing, or excavation-insertion. Injection is the emplacement of dissolved reagents or colloidal suspensions into the soil at elevated pressures. In situ mechanical mixing is the physical blending of the soil and the barrier material underground. Excavation-insertion is the removal of a soil volume and adding barrier materials to the space created. Major vertical barrier emplacement technologies include trenching-backfilling; slurry trenching; and vertical drilling and injection, including boring (earth augering), cable tool drilling, rotary drilling, sonic drilling, jetting methods, injection-mixing in drilled holes, and deep soil mixing. Major horizontal barrier emplacement technologies include horizontal drilling, microtunneling, compaction boring, horizontal emplacement, longwall mining, hydraulic fracturing, and jetting methods.

Riggsbee, W.H.; Treat, R.L.; Stansfield, H.J.; Schwarz, R.M. [Ebasco Environmental, Richland, WA (United States); Cantrell, K.J. [Pacific Northwest Lab., Richland, WA (United States); Phillips, S.J. [Westinghouse Hanford Co., Richland, WA (United States)

1994-02-01T23:59:59.000Z

215

Insights From Laboratory Experiments On Simulated Faults With Application To Fracture Evolution In Geothermal Systems  

Science Conference Proceedings (OSTI)

Laboratory experiments provide a wealth of information related to mechanics of fracture initiation, fracture propagation processes, factors influencing fault strength, and spatio-temporal evolution of fracture properties. Much of the existing literature reports on laboratory studies involving a coupling of thermal, hydraulic, mechanical, and/or chemical processes. As these processes operate within subsurface environments exploited for their energy resource, laboratory results provide insights into factors influencing the mechanical and hydraulic properties of geothermal systems. I report on laboratory observations of strength and fluid transport properties during deformation of simulated faults. The results show systematic trends that vary with stress state, deformation rate, thermal conditions, fluid content, and rock composition. When related to geophysical and geologic measurements obtained from engineered geothermal systems (e.g. microseismicity, wellbore studies, tracer analysis), laboratory results provide a means by which the evolving thermal reservoir can be interpreted in terms of physico-chemical processes. For example, estimates of energy release and microearthquake locations from seismic moment tensor analysis can be related to strength variations observed from friction experiments. Such correlations between laboratory and field data allow for better interpretations about the evolving mechanical and fluid transport properties in the geothermal reservoir – ultimately leading to improvements in managing the resource.

Stephen L. Karner, Ph.D

2006-06-01T23:59:59.000Z

216

San Juan Fracture Characterization Project: Status and current results  

E-Print Network (OSTI)

3 s sweep, 10 sweeps/source Arch Rock #1 Single Well Surveyin Fractured Rock P-wave S-wave P-wave S-wave RIW HW sourceRock #1 VSP Acquisition Single Offset, 9-C VSP P- and S-Wave Vibroseis Sources

2001-01-01T23:59:59.000Z

217

Summary of Research through Phase II/Year 2 of Initially Approved 3 Phase/3 Year Project - Establishing the Relationship between Fracture-Related Dolomite and Primary Rock Fabric on the Distribution of Reservoirs in the Michigan Basin  

SciTech Connect

This final scientific/technical report covers the first 2 years (Phases I and II of an originally planned 3 Year/3 Phase program). The project was focused on evaluating the relationship between fracture-related dolomite and dolomite constrained by primary rock fabric in the 3 most prolific reservoir intervals in the Michigan Basin. The characterization of select dolomite reservoirs was the major focus of our efforts in Phases I and II of the project. Structural mapping and log analysis in the Dundee (Devonian) and Trenton/Black River (Ordovician) suggest a close spatial relationship among gross dolomite distribution and regional-scale, wrench fault-related NW-SE and NE-SW structural trends. A high temperature origin for much of the dolomite in these 2 studied intervals (based upon fluid inclusion homogenization temperatures and stable isotopic analyses,) coupled with persistent association of this dolomite in reservoirs coincident with wrench fault-related features, is strong evidence for these reservoirs being influenced by hydrothermal dolomitization. In the Niagaran (Silurian), there is a general trend of increasing dolomitization shelfward, with limestone predominant in more basinward positions. A major finding is that facies types, when analyzed at a detailed level, are directly related to reservoir porosity and permeability in these dolomites which increases the predictability of reservoir quality in these units. This pattern is consistent with our original hypothesis of primary facies control on dolomitization and resulting reservoir quality at some level. The identification of distinct and predictable vertical stacking patterns within a hierarchical sequence and cycle framework provides a high degree of confidence at this point that the results should be exportable throughout the basin. Much of the data synthesis and modeling for the project was scheduled to be part of Year 3/Phase III, but the discontinuation of funding after Year 2 precluded those efforts. Therefore, the results presented in this document are not final, and in many cases represent a report of 'progress to date' as numerous tasks were scheduled to extend into Year 3.

G. Grammer

2007-09-30T23:59:59.000Z

218

Modeling brine-rock interactions in an enhanced geothermal system deep fractured reservoir at Soultz-Sous-Forets (France): a joint approach using two geochemical codes: frachem and toughreact  

E-Print Network (OSTI)

rock interactions in enhanced geothermal systems (EGS).31 th Workshop on Geothermal Reservoir Engineering, 301998). Computer modeling for geothermal systems: predicting

Andre, Laurent; Spycher, Nicolas; Xu, Tianfu; Vuataz, Francois-D.; Pruess, Karsten.

2006-01-01T23:59:59.000Z

219

A Thermoelastic Hydraulic Fracture Design Tool for Geothermal Reservoir Development  

DOE Green Energy (OSTI)

Geothermal energy is recovered by circulating water through heat exchange areas within a hot rock mass. Geothermal reservoir rock masses generally consist of igneous and metamorphic rocks that have low matrix permeability. Therefore, cracks and fractures play a significant role in extraction of geothermal energy by providing the major pathways for fluid flow and heat exchange. Thus, knowledge of conditions leading to formation of fractures and fracture networks is of paramount importance. Furthermore, in the absence of natural fractures or adequate connectivity, artificial fracture are created in the reservoir using hydraulic fracturing. At times, the practice aims to create a number of parallel fractures connecting a pair of wells. Multiple fractures are preferred because of the large size necessary when using only a single fracture. Although the basic idea is rather simple, hydraulic fracturing is a complex process involving interactions of high pressure fluid injections with a stressed hot rock mass, mechanical interaction of induced fractures with existing natural fractures, and the spatial and temporal variations of in-situ stress. As a result it is necessary to develop tools that can be used to study these interactions as an integral part of a comprehensive approach to geothermal reservoir development, particularly enhanced geothermal systems. In response to this need we have set out to develop advanced thermo-mechanical models for design of artificial fractures and rock fracture research in geothermal reservoirs. These models consider the significant hydraulic and thermo-mechanical processes and their interaction with the in-situ stress state. Wellbore failure and fracture initiation is studied using a model that fully couples poro-mechanical and thermo-mechanical effects. The fracture propagation model is based on a complex variable and regular displacement discontinuity formulations. In the complex variable approach the displacement discontinuities are defined from the numerical solution of a complex hypersingular integral equation written for a given fracture configuration and loading. The fracture propagation studies include modeling interaction of induced fractures with existing discontinuities such as faults and joints. In addition to the fracture propagation studies, two- and three-dimensional heat extraction solution algorithms have been developed and used to estimate heat extraction and the variations of the reservoir stress with cooling. The numerical models have been developed in a user-friendly environment to create a tool for improving fracture design and investigating single or multiple fracture propagation in rock.

Ahmad Ghassemi

2003-06-30T23:59:59.000Z

220

Gas Permeability of Fractured Sandstone/Coal Samples under Variable Confining Pressure  

E-Print Network (OSTI)

of Fractured Sandstone/Coal Samples Smeulders, D.M.J. ,stress on permeability of coal. Int. J. Rock Mech. Min. Sci.of Fractured Sandstone/Coal Samples under Variable Con?ning

Liu, Weiqun; Li, Yushou; Wang, Bo

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Pressure analysis of the hydromechanical fracture behaviour in stimulated tight sedimentary geothermal reservoirs  

E-Print Network (OSTI)

in jointed and layered rocks in geothermal fields.of Volcanology and Geothermal Research 116, 257- 278.fracturing in a sedimentary geothermal reservoir: Results

Wessling, S.

2009-01-01T23:59:59.000Z

222

ESF Subsurface Standby Generator Analysis  

Science Conference Proceedings (OSTI)

The purpose of this analysis is to outline and recommend two standby generator systems. These systems shall provide power during a utility outage to critical Alcove No.5's thermal test loads and to subsurface flow through ventilation loads. Critical loads that will be supported by these generator systems will be identified and evaluated. Additionally, other requirements from the Exploratory Studies Facilities Design Requirements (ESFDR) document will be evaluated. Finally, the standby generator systems will be integrated into the existing ESF subsurface distribution system. The objective of this analysis is to provide design inputs for an efficient and reliable standby generator systems which will provide power for critical loads during a power outage; specifically, Alcove No.5's thermal test loads and the subsurface flow through ventilation loads. Additionally, preliminary one-line diagrams will be developed using this analysis as a primary input.

L. Fernandez

1998-04-17T23:59:59.000Z

223

Modeling and Simulation of Pore Scale Multiphase Fluid Flow and Reactive Transport in Fractured and Porous Media  

Science Conference Proceedings (OSTI)

In the subsurface fluids play a critical role by transporting dissolved minerals, colloids and contaminants (sometimes over long distances), by mediating dissolution and precipitation processes and enabling chemical transformations in solution and at mineral surfaces. Although the complex geometries of fracture apertures, fracture networks and pore spaces may make it difficult to accurately predict fluid flow in saturated (single-phase) subsurface systems, well developed methods are available. The simulation of multiphase fluid flow in the subsurface is much more challenging because of the large density and/or viscosity ratios found in important applications (water/air in the vadose zone, water/oil, water/gas, gas/oil and water/oil/gas in oil reservoirs, water/air/non-aqueous phase liquids (NAPL) in contaminated vadose zone systems and gas/molten rock in volcanic systems, for example). In addition, the complex behavior of fluid-fluid-solid contact lines, and its impact on dynamic contact angles, must also be taken into account, and coupled with the fluid flow. Pore network models and simple statistical physics based models such as the invasion percolation and diffusion-limited aggregation models have been used quite extensively. However, these models for multiphase fluid flow are based on simplified models for pore space geometries and simplified physics. Other methods such a lattice Boltzmann and lattice gas models, molecular dynamics, Monte Carlo methods, and particle methods such as dissipative particle dynamics and smoothed particle hydrodynamics are based more firmly on first principles, and they do not require simplified pore and/or fracture geometries. However, they are less (in some cases very much less) computationally efficient that pore network and statistical physics models. Recently a combination of continuum computation fluid dynamics, fluid-fluid interface tracking or capturing and simple models for the dependence of contact angles on fluid velocity at the contact line has been used to simulate multiphase fluid flow in fracture apertures, fracture networks and pore spaces. Fundamental conservation principles - conservation of momentum, and conservation of mass (or conservation of volume for incompressible fluids) and conservation of energy, as well as symmetries (Galilean invariance and isotropy) are central to the physics of fluids and the models used to simulate them. In molecular and mesoscale models observance of these conservation principles and symmetries at the microscopic level leads to macroscopic fluid dynamics that can be represented by the Navier Stokes equation. The remarkable fact that the flow of all simpe fluids, irrespective of their chemical nature, can be described by the Navier-Stokes equation is a result of these conservation principles and symmetries acting on the molecular level.

Paul Meakin; Alexandre Tartakovsky

2009-07-01T23:59:59.000Z

224

Characterization of subsurface fracture patterns in the Coso...  

Open Energy Info (EERE)

show that most events with paths within the critical angle that defines the shear-wave window, display clear shear-wave splitting, and the fast shear waves have predominant...

225

Hydraulic Fracturing Technology | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Oil & Gas » Shale Gas » Hydraulic Oil & Gas » Shale Gas » Hydraulic Fracturing Technology Hydraulic Fracturing Technology Image taken from "Shale Gas: Applying Technology to Solve America's Energy Challenges," NETL, 2011. Image taken from "Shale Gas: Applying Technology to Solve America's Energy Challenges," NETL, 2011. Hydraulic fracturing is a technique in which large volumes of water and sand, and small volumes of chemical additives are injected into low-permeability subsurface formations to increase oil or natural gas flow. The injection pressure of the pumped fluid creates fractures that enhance gas and fluid flow, and the sand or other coarse material holds the fractures open. Most of the injected fluid flows back to the wellbore and is pumped to the surface.

226

Domain Decomposition for Flow in Porous Media with Fractures  

E-Print Network (OSTI)

this article. The fractures that we are concerned with are filled with debris so we consider them as porous media. The permeability in the fracture is large in comparison with that in the surrounding rock, so the fluid circulates faster in the fracture. Thus we have a highly heterogeneous porous medium. One idea that has been used to take this into account is to treat the fracture as an interface and to assume that the fluid that flows into the fracture stays in the fracture. In fact, in many models the contrast in permeabilities is of such an order that the flow outside of the fracture is neglected. However, here we are concerned with the situation in which the exchange between the fracture and the rest of the domain is significant. To deal with this case we need to model both what happens in the fracture and what happens outside the fracture. One

Clarisse Alboin; Jerome Jaffre; Jean Roberts; Christophe Serres

1999-01-01T23:59:59.000Z

227

Spatial Orientation And Distribution Of Reservoir Fractures From Scattered Seismic Energy  

E-Print Network (OSTI)

Expanded details and additional results are presented using a new method (Willis et al, 2003) for determining the reflection and scattering characteristics of seismic energy from subsurface fractured formations. The method ...

Vetri, Laura

2004-01-01T23:59:59.000Z

228

Experimental Study of Acid Fracture Conductivity of Austin Chalk Formation  

E-Print Network (OSTI)

Acid fracture conductivity and the effect of key variables in the etching process during acid fracturing can be assessed at the laboratory scale. This is accomplished by using an experimental apparatus that simulates acid injection fluxes comparable to those in actual acid fracture treatments. After acid etching, fracture conductivity is measured at different closure stresses. This research work presents a systematic study to investigate the effect of temperature, rock-acid contact time and initial condition of the fracture surfaces on acid fracture conductivity in the Austin Chalk formation. While temperature and rock-acid contact are variables normally studied in fracture conductivity tests, the effect of the initial condition of the fracture surface has not been extensively investigated. The experimental results showed that there is no significant difference in acid fracture conductivity at high closure stress using smooth or rough fracture surfaces. In addition, we analyzed the mechanisms of acid etching and resulting conductivity creation in the two types of fracture surfaces studied by using surface profiles. For smooth surfaces, the mechanism of conductivity creation seems connected to uneven etching of the rock and roughness generation. For rough surfaces, acid conductivity is related to smoothing and deepening of the initial features on the sample surface than by creating more roughness. Finally, we compared the experimental results with Nirode-Kruk correlation for acid fracture conductivity.

Nino Penaloza, Andrea

2013-05-01T23:59:59.000Z

229

Fractured shale reservoirs: Towards a realistic model  

Science Conference Proceedings (OSTI)

Fractured shale reservoirs are fundamentally unconventional, which is to say that their behavior is qualitatively different from reservoirs characterized by intergranular pore space. Attempts to analyze fractured shale reservoirs are essentially misleading. Reliance on such models can have only negative results for fractured shale oil and gas exploration and development. A realistic model of fractured shale reservoirs begins with the history of the shale as a hydrocarbon source rock. Minimum levels of both kerogen concentration and thermal maturity are required for effective hydrocarbon generation. Hydrocarbon generation results in overpressuring of the shale. At some critical level of repressuring, the shale fractures in the ambient stress field. This primary natural fracture system is fundamental to the future behavior of the fractured shale gas reservoir. The fractures facilitate primary migration of oil and gas out of the shale and into the basin. In this process, all connate water is expelled, leaving the fractured shale oil-wet and saturated with oil and gas. What fluids are eventually produced from the fractured shale depends on the consequent structural and geochemical history. As long as the shale remains hot, oil production may be obtained. (e.g. Bakken Shale, Green River Shale). If the shale is significantly cooled, mainly gas will be produced (e.g. Antrim Shale, Ohio Shale, New Albany Shale). Where secondary natural fracture systems are developed and connect the shale to aquifers or to surface recharge, the fractured shale will also produce water (e.g. Antrim Shale, Indiana New Albany Shale).

Hamilton-Smith, T. [Applied Earth Science, Lexington, KY (United States)

1996-09-01T23:59:59.000Z

230

Rock-Water Interactions In Hot Dry Rock Geothermal Systems- Field  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Rock-Water Interactions In Hot Dry Rock Geothermal Systems- Field Investigations Of In Situ Geochemical Behavior Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Rock-Water Interactions In Hot Dry Rock Geothermal Systems- Field Investigations Of In Situ Geochemical Behavior Details Activities (5) Areas (2) Regions (0) Abstract: Two hot dry rock (HDR) geothermal energy reservoirs have been created by hydraulic fracturing of Precambrian granitic rock between two wells on the west flank of the Valles Caldera in the Jemez Mountains of northern New Mexico. Heat is extracted by injecting water into one well,

231

SUBSURFACE VISUAL ALARM SYSTEM ANALYSIS  

SciTech Connect

The ''Subsurface Fire Hazard Analysis'' (CRWMS M&O 1998, page 61), and the document, ''Title III Evaluation Report for the Surface and Subsurface Communication System'', (CRWMS M&O 1999a, pages 21 and 23), both indicate the installed communication system is adequate to support Exploratory Studies Facility (ESF) activities with the exception of the mine phone system for emergency notification purposes. They recommend the installation of a visual alarm system to supplement the page/party phone system The purpose of this analysis is to identify data communication highway design approaches, and provide justification for the selected or recommended alternatives for the data communication of the subsurface visual alarm system. This analysis is being prepared to document a basis for the design selection of the data communication method. This analysis will briefly describe existing data or voice communication or monitoring systems within the ESF, and look at how these may be revised or adapted to support the needed data highway of the subsurface visual alarm. system. The existing PLC communication system installed in subsurface is providing data communication for alcove No.5 ventilation fans, south portal ventilation fans, bulkhead doors and generator monitoring system. It is given that the data communication of the subsurface visual alarm system will be a digital based system. It is also given that it is most feasible to take advantage of existing systems and equipment and not consider an entirely new data communication system design and installation. The scope and primary objectives of this analysis are to: (1) Briefly review and describe existing available data communication highways or systems within the ESF. (2) Examine technical characteristics of an existing system to disqualify a design alternative is paramount in minimizing the number of and depth of a system review. (3) Apply general engineering design practices or criteria such as relative cost, and degree of difficulty and complexity in determining requirements in adapting existing data communication highways to support the subsurface visual alarm system. These requirements would include such things as added or new communication cables, added Programmable Logic Controller (PLC), Inputs and Outputs (I/O), and communication hardware components, and human machine interfaces and their software operating system. (4) Select the best data communication highway system based on this review of adapting or integrating with existing data communication systems.

D.W. Markman

2001-08-06T23:59:59.000Z

232

Development of hot dry rock resources  

DOE Green Energy (OSTI)

The LASL Hot Dry Rock Geothermal Energy Project is the only U.S. field test of this geothermal resource. In the LASL concept, a man-made geothermal reservoir would be formed by drilling a deep hole into relatively impermeable hot rock, creating a large surface area for heat transfer by fracturing the rock hydraulically, then drilling a second hole to intersect the fracture to complete the circulation loop. In 1974, the first hole was drilled to a depth of 2929 m (9610 ft) and a hydraulic fracture was produced near the bottom. In 1975, a second hole was directionally drilled to intersect the fracture. Although the desired intersection was not achieved, a connection was made through which water was circulated. After a year's study of the fracture system, drilling began again in April 1977 and an improved connection was achieved. In September of 1977 a 5 MW (thermal) heat extraction and circulation experiment was conducted for 100 h as a preliminary test of the concept. An 1800-h circulation experiment was concluded on April 13, 1978 to determine temperature-drawdown, permeation water loss and flow characteristics of the pressurized reservoir, to examine chemistry changes in the circulating fluid, and to monitor for induced seismic effects.

Pettitt, R.A.; Tester, J.W.

1978-01-01T23:59:59.000Z

233

Hydraulic fracture experiments in GT-1 and GT-2  

DOE Green Energy (OSTI)

Hydraulic fracturing experiments were conducted in granite rock, at temperatures near 100 and 150/sup 0/C, in two wells 0.785 km (2575 ft) and 1.98 km (6500 ft) deep near Los Alamos, New Mexico. No unusual difficulty was observed in fracturing crystalline rock hydraulically. The apparent surface energy (energy required to create new fracture surface by breaking the rock) was measured as 100 J/m/sup 2/. Orientation of the deeper fracture was measured as N35/sup 0/E (+-5/sup 0/). The fraction of fluid injected into the rock that could be recovered at hydrostatic surface pressure was measured. The efficiency of recovery was as high as 92 percent after the fracture impedance was lowered by ''propping'' the fracture with sand. Permeability of the rock over the face of the fracture was compatible with laboratory measurements (10/sup -7/ to 10/sup -8/ darcys). Downhole pressures required to extend the fractures were about 150 and 340 bars (2175 and 4900 psi), respectively.

Aamodt, R.L.

1977-02-01T23:59:59.000Z

234

Subsurface Knowledge Reference Page | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Subsurface Knowledge Reference Page Subsurface Knowledge Reference Page Subsurface Knowledge Reference Page The below listing provides additional references related to Subsurface & Groundwater Remediation. The references are categorized by documents types (e.g., Strategic Plans, Groundwater Plume Map Booklets, etc.) and under each "document type", there is a list of documents and/or hyperlinks to a reference. The Subsurface Knowledge Reference Page will continue to reflect additional information as it is identified. Strategic Plans Scientific Opportunities to Reduce Risk in Groundwater and Soil Remediation Scientific Opportunities for Monitoring at Environmental Remediation Sites (SOMERS) Groundwater Plume Map Booklets Groundwater Contamination and Treatment at Department of Energy Sites -

235

EMSL: Science: Terrestrial & Subsurface Ecosystems  

NLE Websites -- All DOE Office Websites (Extended Search)

Terrestrial & Subsurface Ecosystems Terrestrial & Subsurface Ecosystems Terrestrial and Subsurface Ecosystems logo Visualization of CFD-simulated fluid velocities within a single pore space between randomly packed spherical grains Visualization of CFD-simulated fluid velocities within a single pore space between randomly packed spherical grains. The Terrestrial and Subsurface Ecosystems Science Theme focuses on the dynamics of nutrients, metabolites, and contaminants at biogeochemical interfaces in heterogeneous environments across multiple scales. By providing a mechanistic understanding of biogeochemical and microbial processes in soils and the subsurface, and linking those processes via pore-scale hydrological models, EMSL can improve strategies for sustainable solutions to contaminant attenuation, remediation and biogeochemical

236

RESEARCH PROGRAM ON FRACTURED PETROLEUM RESERVOIRS  

Science Conference Proceedings (OSTI)

Numerical simulation of water injection in discrete fractured media with capillary pressure is a challenge. Dual-porosity models in view of their strength and simplicity can be mainly used for sugar-cube representation of fractured media. In such a representation, the transfer function between the fracture and the matrix block can be readily calculated for water-wet media. For a mixed-wet system, the evaluation of the transfer function becomes complicated due to the effect of gravity. In this work, they use a discrete-fracture model in which the fractures are discretized as one dimensional entities to account for fracture thickness by an integral form of the flow equations. This simple step greatly improves the numerical solution. Then the discrete-fracture model is implemented using a Galerkin finite element method. The robustness and the accuracy of the approach are shown through several examples. First they consider a single fracture in a rock matrix and compare the results of the discrete-fracture model with a single-porosity model. Then, they use the discrete-fracture model in more complex configurations. Numerical simulations are carried out in water-wet media as well as in mixed-wet media to study the effect of matrix and fracture capillary pressures.

Abbas Firoozabadi

2002-04-12T23:59:59.000Z

237

Modeling the cracking process of rocks from continuity to discontinuity using a cellular automaton  

Science Conference Proceedings (OSTI)

A rock discontinuous cellular automaton (RDCA) was developed for modeling rock fracturing processes from continuous to discontinuous deformation under mechanical loading. RDCA is an integration of the following basic concepts: (1) representation of heterogeneity ... Keywords: Cracking process, Discontinuity, Elasto-plastic cellular automaton, Level set, Partition of unity, Rock discontinuous cellular automaton

Peng-Zhi Pan; Fei Yan; Xia-Ting Feng

2012-05-01T23:59:59.000Z

238

Injection into a fractured geothermal reservoir  

DOE Green Energy (OSTI)

A detailed study is made on the movement of the thermal fronts in the fracture and in the porous medium when 100{sup 0}C water is injected into a 300{sup 0}C geothermal reservoir with equally spaced horizontal fractures. Numerical modeling calculations were made for a number of thermal conductivity values, as well as different values of the ratio of fracture and rock medium permeabilities. One important result is an indication that although initially, the thermal front in the fracture moves very fast relative to the front in the porous medium as commonly expected, its speed rapidly decreases. At some distance from the injection well the thermal fronts in the fracture and the porous medium coincide, and from that point they advance together. The implication of this result on the effects of fractures on reinjection into geothermal reservoirs is discussed.

Bodvarsson, G.S.; Tsang, C.F.

1980-05-01T23:59:59.000Z

239

Method of installing subsurface barrier  

DOE Patents (OSTI)

Systems, components, and methods relating to subterranean containment barriers. Laterally adjacent tubular casings having male interlock structures and multiple female interlock structures defining recesses for receiving a male interlock structure are used to create subterranean barriers for containing and treating buried waste and its effluents. The multiple female interlock structures enable the barriers to be varied around subsurface objects and to form barrier sidewalls. The barrier may be used for treating and monitoring a zone of interest.

Nickelson, Reva A. (Shelley, ID); Richardson, John G. (Idaho Falls, ID); Kostelnik, Kevin M. (Idaho Falls, ID); Sloan, Paul A. (Rigby, ID)

2007-10-09T23:59:59.000Z

240

Rock properties in support of geothermal resource development  

DOE Green Energy (OSTI)

Geothermal rock mechanics needs have been defined and subsequently a test system was designed and built for providing appropriate material properties. The development areas identified as requiring rock mechanics were stimulation, reservoir engineering, subsidence prediction, surface exploration and subsurface evaluation, and drilling. The resulting test system provides mechanical, electrical, thermal and physical properties on 2 and 4 inch diameter cores at confining pressures and pore fluid pressures to 200 MPa (30,000 psi) and temperatures to 535/sup 0/C (1000/sup 0/F). The test system development was continued and site specific rock mechanics requirements were identified. (MHR)

Butters, S.W.

1979-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Studies of injection into naturally fractured reservoirs  

DOE Green Energy (OSTI)

A semi-analytical model for studies of cold water injection into naturally fractured reservoirs has been developed. The model can be used to design the flow rates and location of injection wells in such systems. The results obtained using the model show that initially the cold water will move very rapidly through the fracture system away from the well. Later on, conductive heat transfer from the rock matrix blocks will retard the advancement of the cold water front, and eventually uniform energy sweep conditions will prevail. Where uniform energy sweep conditions are reached the cold waer movement away from the injection well will be identical to that in a porous medium; consequently maximum energy recovery from the rock matrix will be attained. The time of uniform energy sweep and the radial distance from the injection well where it occurs are greatly dependent upon the fracture spacing, but independent of the fracture aperture.

Boedvarsson, G.S.; Lai, C.H.

1982-10-01T23:59:59.000Z

242

Hydraulic Fracturing (Vermont)  

Energy.gov (U.S. Department of Energy (DOE))

Vermont prohibits hydraulic fracturing or the collection, storage, or treatment of wastewater from hydraulic fracturing

243

Investigation of the effect of gel residue on hydraulic fracture conductivity using dynamic fracture conductivity test  

E-Print Network (OSTI)

The key to producing gas from tight gas reservoirs is to create a long, highly conductive flow path, via the placement of a hydraulic fracture, to stimulate flow from the reservoir to the wellbore. Viscous fluid is used to transport proppant into the fracture. However, these same viscous fluids need to break to a thin fluid after the treatment is over so that the fracture fluid can be cleaned up. In shallower, lower temperature (less than 250°F) reservoirs, the choice of a fracture fluid is very critical to the success of the treatment. Current hydraulic fracturing methods in unconventional tight gas reservoirs have been developed largely through ad-hoc application of low-cost water fracs, with little optimization of the process. It seems clear that some of the standard tests and models are missing some of the physics of the fracturing process in low-permeability environments. A series of the extensive laboratory "dynamic fracture conductivity" tests have been conducted. Dynamic fracture conductivity is created when proppant slurry is pumped into a hydraulic fracture in low permeability rock. Unlike conventional fracture conductivity tests in which proppant is loaded into the fracture artificially, we pump proppant/ fracturing fluid slurries into a fracture cell, dynamically placing the proppant just as it occurs in the field. Test results indicate that increasing gel concentration decreases retained fracture conductivity for a constant gas flow rate and decreasing gas flow rate decreases retained fracture conductivity. Without breaker, the damaging effect of viscous hydraulic fracturing fluids on the conductivity of proppant packs is significant at temperature of 150°F. Static conductivity testing results in higher retained fracture conductivity when compared to dynamic conductivity testing.

Marpaung, Fivman

2007-12-01T23:59:59.000Z

244

Investigation of the effect of gel residue on hydraulic fracture conductivity using dynamic fracture conductivity test  

E-Print Network (OSTI)

The key to producing gas from tight gas reservoirs is to create a long, highly conductive flow path, via the placement of a hydraulic fracture, to stimulate flow from the reservoir to the wellbore. Viscous fluid is used to transport proppant into the fracture. However, these same viscous fluids need to break to a thin fluid after the treatment is over so that the fracture fluid can be cleaned up. In shallower, lower temperature (less than 250oF) reservoirs, the choice of a fracture fluid is very critical to the success of the treatment. Current hydraulic fracturing methods in unconventional tight gas reservoirs have been developed largely through ad-hoc application of low-cost water fracs, with little optimization of the process. It seems clear that some of the standard tests and models are missing some of the physics of the fracturing process in low-permeability environments. A series of the extensive laboratory “dynamic fracture conductivity” tests have been conducted. Dynamic fracture conductivity is created when proppant slurry is pumped into a hydraulic fracture in low permeability rock. Unlike conventional fracture conductivity tests in which proppant is loaded into the fracture artificially, we pump proppant/ fracturing fluid slurries into a fracture cell, dynamically placing the proppant just as it occurs in the field. Test results indicate that increasing gel concentration decreases retained fracture conductivity for a constant gas flow rate and decreasing gas flow rate decreases retained fracture conductivity. Without breaker, the damaging effect of viscous hydraulic fracturing fluids on the conductivity of proppant packs is significant at temperature of 150oF. Static conductivity testing results in higher retained fracture conductivity when compared to dynamic conductivity testing.

Marpaung, Fivman

2007-12-01T23:59:59.000Z

245

Hot Dry Rock Geothermal Reservoir Model Development at Los Alamos  

DOE Green Energy (OSTI)

Discrete fracture and continuum models are being developed to simulate Hot Dry Rock (HDR) geothermal reservoirs. The discrete fracture model is a two-dimensional steady state simulator of fluid flow and tracer transport in a fracture network which is generated from assumed statistical properties of the fractures. The model's strength lies in its ability to compute the steady state pressure drop and tracer response in a realistic network of interconnected fractures. The continuum approach models fracture behavior by treating permeability and porosity as functions of temperature and effective stress. With this model it is practical to model transient behavior as well as the coupled processes of fluid flow, heat transfer, and stress effects in a three-dimensional system. The model capabilities being developed will also have applications in conventional geothermal systems undergoing reinjection and in fractured geothermal reservoirs in general.

Robinson, Bruce A.; Birdsell, Stephen A.

1989-03-21T23:59:59.000Z

246

Hot Dry Rock geothermal reservoir model development at Los Alamos  

DOE Green Energy (OSTI)

Discrete fracture and continuum models are being developed to simulate Hot Dry Rock (HDR) geothermal reservoirs. The discrete fracture model is a two-dimensional steady state simulator of fluid flow and tracer transport in a fracture network which is generated from assumed statistical properties of the fractures. The model's strength lies in its ability to compute the steady state pressure drop and tracer response in a realistic network of interconnected fractures. The continuum approach models fracture behavior by treating permeability and porosity as functions of temperature and effective stress. With this model it is practical to model transient behavior as well as the coupled processes of fluid flow, heat transfer, and stress effects in a three-dimensional system. The model capabilities being developed will also have applications in conventional geothermal systems undergoing reinjection and in fractured geothermal reservoirs in general. 15 refs., 7 figs.

Robinson, B.A.; Birdsell, S.A.

1989-01-01T23:59:59.000Z

247

Hot dry rock energy project  

DOE Green Energy (OSTI)

A proof-of-concept experimental project by the Los Alamos Scientific Laboratory endeavors to establish the feasibility of exploitation of the thermal energy contained in the earth's crust where such energy and a transporting fluid have not been juxtaposed in nature. A region of high heat flow and apparently unfaulted basement rock formation was selected. Two boreholes, drilled to a total depth of about 3 km (10,000 ft) and penetrating about 2.5 km (7500 ft) into the Precambrian formation, to a rock temperature of 200/sup 0/C, have been connected at depth by a hydraulically fractured zone to form the heat extraction surface. Energy was extracted at a rate of 3.2 MW(t) with water temperature of 132/sup 0/C during a 96-h preliminary circulating test run performed late in September 1977. This paper traces the progress of the project, summarizes procedures and salient events, and references detailed reports and specialized topics.

Hendron, R.H.

1977-01-01T23:59:59.000Z

248

Hot dry rock Phase II reservoir engineering  

DOE Green Energy (OSTI)

Early attempts to hydraulically fracture and connect two wells drilled at the Hot Dry Rock site at Fenton Hill in New Mexico failed. Microearthquakes triggered by hydraulic fracturing indicated that the fracture zones grew in unexpected directions. Consequently one of the wells was sidetracked at a depth of 2.9 km; was redrilled into the zones of most intense microseismic activity; and a flow connection was achieved. Hydraulic communication was improved by supplemental fracturing using recently developed high temperature and high pressure open hole packers. Preliminary testing indicates a reservoir with stimulated joint volume which already surpasses that attained in the earlier phase I reservoir after several years of development. 12 refs., 6 figs.

Murphy, H.D.

1985-01-01T23:59:59.000Z

249

Hydraulic fracturing of jointed formations  

DOE Green Energy (OSTI)

Measured by volume, North America's largest hydraulic fracturing operations have been conducted at Fenton Hill, New Mexico to create geothermal energy reservoirs. In the largest operation 21,000 m/sup 3/ of water were injected into jointed granitic rock at a depth of 3.5 km. Microearthquakes induced by this injection were measured with geophones placed in five wells drilled into, or very close, to the reservoir, as well as 11 surface seismometers. The large volume of rock over which the microearthquakes were distributed indicates a mechanism of hydraulic stimulation which is at odds with conventional fracturing theory, which predicts failure along a plane which is perpendicular to the least compressive earth stress. A coupled rock mechanics/fluid flow model provides much of the explanation. Shear slippage along pre-existing joints in the rock is more easily induced than conventional tensile failure, particularly when the difference between minimum and maximum earth stresses is large and the joints are oriented at angles between 30 and 60 degrees to the principal earth stresses, and a low viscosity fluid like water is injected. Shear slippage results in local redistribution of stresses, which allows a branching, or dendritic, stimulation pattern to evolve, in agreement with the patterns of microearthquake locations. These results are qualitatively similar to the controversial process known as ''Kiel'' fracturing, in which sequential injections and shut-ins are repeated to create dendritic fractures for enhanced oil and gas recovery. However, we believe that the explanation is shear slippage of pre-existing joints and stress redistribution, not proppant bridging and fluid blocking as suggested by Kiel. 15 refs., 10 figs.

Murphy, H.D.; Fehler, M.C.

1986-01-01T23:59:59.000Z

250

Mechanical and acoustic properties of weakly cemented granular rocks  

SciTech Connect

This paper presents the results of laboratory measurements on the mechanical and acoustic properties of weakly cemented granular rock. Artificial rock samples were fabricated by cementing sand and glass beads with sodium silicate binder. During uniaxial compression tests, the rock samples showed stress-strain behavior which was more similar to that of soils than competent rocks, exhibiting large permanent deformations with frictional slip. The mechanical behavior of the samples approached that of competent rocks as the amount of binder was increased. For very weak samples, acoustic waves propagating in these rocks showed very low velocities of less than 1000 m/sec for compressional waves. A borehole made within this weakly cemented rock exhibited a unique mode of failure that is called ''anti-KI mode fracture'' in this paper. The effect of cementation, grain type, and boundary conditions on this mode of failure was also examined experimentally.

Nakagawa, S.; Myer, L.R.

2001-05-09T23:59:59.000Z

251

Geothermal Environmental Impact Assessment: Subsurface Environmental Assessment for Four Geothermal Systems  

DOE Green Energy (OSTI)

Geothermal systems are described for Imperial Valley and The Geysers, California; Klamath Falls, Oregon; and the Rio Grande Rift Zone, New Mexico; including information on location, area, depth, temperature, fluid phase and composition, resource base and status of development. The subsurface environmental assessment evaluates potential groundwater degradation, seismicity and subsidence. A general discussion on geothermal systems, pollution potential, chemical characteristics of geothermal fluids and environmental effects of geothermal water pollutants is presented as background material. For the Imperial Valley, all publicly available water quality and location data for geothermal and nongeothermal wells in and near the East Mesa, Salton Sea, Heber, Brawley, Dunes and Glamis KGRAs have been compiled and plotted. The geothermal fluids which will be reinjected range in salinity from a few thousand to more than a quarter million ppm. Although Imperial Valley is a major agricultural center, groundwater use in and near most of these KGRAs is minimal. Extensive seismicity and subsidence monitoring networks have been established in this area of high natural seismicity and subsidence. The vapor-dominated Geysers geothermal field is the largest electricity producer in the world. Groundwater in this mountainous region flows with poor hydraulic continuity in fractured rock. Ground and surface water quality is generally good, but high boron concentrations in hot springs and geothermal effluents is of significant concern; however, spent condensate is reinjected. High microearthquake activity is noted around the geothermal reservoir and potential subsidence effects are considered minimal. In Klamath Falls, geothermal fluids up to 113 C (235 F) are used for space heating, mostly through downhole heat exchangers with only minor, relatively benign, geothermal fluid being produced at the surface. Seismicity is low and is not expected to increase. Subsidence is not recognized. Of all geothermal occurrences in the Rio Grande Rift, the Valles Caldera is currently of primary interest. injection of geothermal effluent from hydrothermal production wells should remove any hydrologic hazard due to some potentially noxious constituents. Waters circulating in the LASL Hot Dry Rock experiment are potable. Seismic effects are expected to be minimal. Subsidence effects could develop.

Sanyal, Subir; Weiss, Richard

1978-11-01T23:59:59.000Z

252

Calculation of explosive rock breakage: oil shale  

SciTech Connect

Improved efficiency in explosive rock breakage becomes increasingly important as mining costs and the need to tap underground resources continue to grow. Industry has recognized this need for many years and has done a great deal in developing new products and new blasting techniques, generally by purely empirical means. One particular application that has received added attention within the past several years, and one that lends itself to a more objective theoretical study, is explosive fracture of oil shale for conventional and in situ fossil energy recovery. Numerical calculation of oil shale fracturization with commercial explosives has the potential to add to an objective understanding of the breakage process. Often, in such numerical studies, only one or two parts of the total problem are addressed with any degree of sophistication or completeness. Here an attempt is made to treat the entire problem, i.e., explosive characterization, constitutive behavior of intact rock, and a mathematical description of rock fracture. The final results are two-dimensional calculations of explosively induced fracture damage in oil shale.

Johnson, J.N.

1979-01-01T23:59:59.000Z

253

Fracture analysis of the upper devonian antrim shale, Michigan basin  

Science Conference Proceedings (OSTI)

The Antrim Shale is a fractured, unconventional gas reservoir in the northern Michigan basin. Controls on gas production are poorly constrained but must depend on the fracture framework. Analyses of fracture geometry (orientation, spacing, and aperture width) were undertaken to better evaluate reservoir permeability and, hence, pathways for fluid migration. Measurements from nearly 600 fractures were made from outcrop, core, and Formation MicroScanner logs covering three members of the Antrim Shale (Norwood, Paxton, Lachine) and the Ellsworth Shale. Fracture analyses indicate pronounced reservoir anisotropy among the members. Together related with lithologic variations, this leads to unique reservoir characteristics within each member. There are two dominant fracture sets, northeast-southwest and northwest-southeast. Fracture density varies among stratigraphic intervals but always is lowest in the northwest-southeast fracture set and is greatest in the northeast-southwest fracture set. While aperture width decreases markedly with depth, subsurface variation in mean aperture width is significant. Based on fracture density and mean aperture width, the Norwood member has the largest intrinsic permeability and the Ellsworth Shale the lowest intrinsic permeability. The highest intrinsic fracture permeability in all intervals is associated with the northeast-southwest fracture set. The Norwood and Lachine members thus exhibit the best reservoir character. This information is useful in developing exploration strategies and completion practices in the Antrim Shale gas play.

Richards, J.A.; Budai, J.M.; Walter, L.M.; Abriola, L.M. (Univ. of Michigan, Ann Arbor, MI (United States))

1994-08-01T23:59:59.000Z

254

Regional Analysis And Characterization Of Fractured Aquifers In The  

Open Energy Info (EERE)

Analysis And Characterization Of Fractured Aquifers In The Analysis And Characterization Of Fractured Aquifers In The Virginia Blue Ridge And Piedmont Provinces Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: Regional Analysis And Characterization Of Fractured Aquifers In The Virginia Blue Ridge And Piedmont Provinces Details Activities (1) Areas (1) Regions (0) Abstract: Areas related to low-temperature geothermal applications include the recognition of and exploration for deep fracture permeability in crystalline rocks. It is well known that the best currently available downhole techniques to identify the locations of fracture zones in crystalline rocks depend upon the measurement of some thermal parameter such as temperature or heat flow. The temperature-depth profiles and their derivatives provide a direct indication of those fracture zones that

255

Modeling of fluid and heat flow in fractured geothermal reservoirs  

DOE Green Energy (OSTI)

In most geothermal reservoirs large-scale permeability is dominated by fractures, while most of the heat and fluid reserves are stored in the rock matrix. Early-time fluid production comes mostly from the readily accessible fracture volume, while reservoir behavior at later time depends upon the ease with which fluid and heat can be transferred from the rock matrix to the fractures. Methods for modeling flow in fractured porous media must be able to deal with this matrix-fracture exchange, the so-called interporosity flow. This paper reviews recent work at Lawrence Berkeley Laboratory on numerical modeling of nonisothermal multiphase flow in fractured porous media. We also give a brief summary of simulation applications to problems in geothermal production and reinjection. 29 refs., 1 fig.

Pruess, K.

1988-08-01T23:59:59.000Z

256

Subsurface Excavations (Texas) | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

legislation addresses subsurface excavations conducted for all purposes other than the exploration or production of gas and oil resources that may adversely affect water...

257

capabilitiesFlier_subsurfaceFlow_WEB  

NLE Websites -- All DOE Office Websites (Extended Search)

use is applied to EMSL's sci- ence themes of Biological Interactions and Dynamics, GeochemistryBiogeochemistry and Subsurface Science, as well as Science of Interfacial...

258

Evaluation and Effect of Fracturing Fluids on Fracture Conductivity in Tight Gas Reservoirs Using Dynamic Fracture Conductivity Test  

E-Print Network (OSTI)

Unconventional gas has become an important resource to help meet our future energy demands. Although plentiful, it is difficult to produce this resource, when locked in a massive sedimentary formation. Among all unconventional gas resources, tight gas sands represent a big fraction and are often characterized by very low porosity and permeability associated with their producing formations, resulting in extremely low production rate. The low flow properties and the recovery factors of these sands make necessary continuous efforts to reduce costs and improve efficiency in all aspects of drilling, completion and production techniques. Many of the recent improvements have been in well completions and hydraulic fracturing. Thus, the main goal of a hydraulic fracture is to create a long, highly conductive fracture to facilitate the gas flow from the reservoir to the wellbore to obtain commercial production rates. Fracture conductivity depends on several factors, such as like the damage created by the gel during the treatment and the gel clean-up after the treatment. This research is focused on predicting more accurately the fracture conductivity, the gel damage created in fractures, and the fracture cleanup after a hydraulic fracture treatment under certain pressure and temperature conditions. Parameters that alter fracture conductivity, such as polymer concentration, breaker concentration and gas flow rate, are also examined in this study. A series of experiments, using a procedure of “dynamical fracture conductivity test”, were carried out. This procedure simulates the proppant/frac fluid slurries flow into the fractures in a low-permeability rock, as it occurs in the field, using different combinations of polymer and breaker concentrations under reservoirs conditions. The result of this study provides the basis to optimize the fracturing fluids and the polymer loading at different reservoir conditions, which may result in a clean and conductive fracture. Success in improving this process will help to decrease capital expenditures and increase the production in unconventional tight gas reservoirs.

Correa Castro, Juan

2011-05-01T23:59:59.000Z

259

Rock melting tool with annealer section  

DOE Patents (OSTI)

A rock melting penetrator is provided with an afterbody that rapidly cools a molten geological structure formed around the melting tip of the penetrator to the glass transition temperature for the surrounding molten glass-like material. An annealing afterbody then cools the glass slowly from the glass transition temperature through the annealing temperature range to form a solid self-supporting glass casing. This allows thermally induced strains to relax by viscous deformations as the molten glass cools and prevents fracturing of the resulting glass liner. The quality of the glass lining is improved, along with its ability to provide a rigid impermeable casing in unstable rock formations.

Bussod, Gilles Y. (Santa Fe, NM); Dick, Aaron J. (Oakland, CA); Cort, George E. (Montrose, CO)

1998-01-01T23:59:59.000Z

260

Mechanical properties of rocks at high temperatures and pressures: Final report  

DOE Green Energy (OSTI)

During the final year of the grant, we have investigated (1) why the strengths of rocks decrease with increasing temperature and in the presence of water through study of the fracture process in Westerly granite and Sioux quartzite specimens deformed in extension (some in true tension), (2) frictional strengths of rocks at high temperatures, (3) the stability of boreholes in fractured rock, and (4) slip in biotite single crystals (in that biotite is probably the weakest and most ductile of the common constituents of crystalline rocks.

Friedman, M.; Bauer, S.J.; Chester, F.M.; Handin, J.; Hopkins, T.W.; Johnson, B.; Kronenberg, A.K.; Mardon, D.; Russell, J.E.

1987-07-27T23:59:59.000Z

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Hydraulic fracturing-1  

Science Conference Proceedings (OSTI)

This book contains papers on hydraulic fracturing. Topics covered include: An overview of recent advances in hydraulic fracturing technology; Containment of massive hydraulic fracture; and Fracturing with a high-strength proppant.

Not Available

1990-01-01T23:59:59.000Z

262

Dynamic rock fragmentation: oil shale applications  

SciTech Connect

Explosive rock fragmentation techniques used in many resource recovery operations have in the past relied heavily upon traditions of field experience for their design. As these resources, notably energy resources, become less accessible, it becomes increasingly important that fragmentation techniques be optimized and that methods be developed to effectively evaluate new or modified explosive deployment schemes. Computational procedures have significant potential in these areas, but practical applications must be preceded by a thorough understanding of the rock fracture phenomenon and the development of physically sound computational models. This paper presents some of the important features of a rock fragmentation model that was developed as part of a program directed at the preparation of subterranean beds for in situ processing of oil shale. The model, which has been implemented in a two-dimensional Lagrangian wavecode, employs a continuum damage concept to quantify the degree of fracturing and takes into account experimental observations that fracture strength and fragment dimensions depend on tensile strain rates. The basic premises of the model are considered in the paper as well as some comparisons between calculated results and observations from blasting experiments.

Boade, R. R.; Grady, D. E.; Kipp, M. E.

1980-01-01T23:59:59.000Z

263

Los Alamos hot dry rock geothermal energy experiment  

DOE Green Energy (OSTI)

Recent heat flow data indicates that about 95,000 sq. mi. in 13 western U.S. states is underlain, at a depth of 5 km (16,400 ft) by hot dry rock at temperatures above 290/sup 0/C (440/sup 0/F.). Therefore a geothermal energy development program was undertaken to develop methods from extracting thermal energy from hot rock in the earth crust by man-made underground circulation systems; demonstrate the commercial feasibility of such systems; and encourage use of this technology. Experiments performed on the Jemez Plateau in New Mexico are described with information on the drilling of boreholes, hydraulic fracturing of hot rocks, well logging, and environmental monitoring to establish base line data and define the potential effects of the project. The technical achievements of the project include boreholes were drilled to 3k (10,000 ft) with bottomhole temperatures of approximately 200/sup 0/C (390/sup 0/F); hydraulic fracturing produced fractured regions with 150 m (500 ft) radii; at least 90 percent of the water injected was recovered; and data was obtained on geologic conditions, seismic effects, and thermal, fracturing, and chemical properties of the downhole rocks. A geothermal power-production system model was formulated for evaluating the total cost of developing power production using a hot-dry-rock geothermal energy source. (LCL)

Pettitt, R.A.

1976-01-01T23:59:59.000Z

264

LASL hot dry rock geothermal energy development project  

DOE Green Energy (OSTI)

The history of the hot-dry-rock project is traced. Efforts to establish a two-hole and connecting fracture system on the southwest flank of the Valles Caldera in north-central New Mexico are summarized. Problems encountered in drilling and hydraulic fracturing are described. Current results with the loop operation for heat extraction are encouraging, and plans for a second energy extraction hole are underway. (JBG)

Hill, J.H.

1978-01-01T23:59:59.000Z

265

Subsurface Biogeochemical Research (SBR) Contractor-Grantee Workshop--Abstracts  

E-Print Network (OSTI)

Abiotic Reactions in Hanford 300 Area Subsurface Sedimentsin the subsurface at Hanford’s 300 Area. To initially studycore samples from the Hanford 300 Area IFRC site. Uranium

Hazen, Terry C.

2010-01-01T23:59:59.000Z

266

Attenuation-Based Remedies in the Subsurface Applied Field Research...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Subsurface Applied Field Research Initiative (ABRS AFRI) Located at the Savannah River Site in Aiken, South Carolina, the Attenuation-Based Remedies in the Subsurface Applied...

267

Characterization of Fractures in Geothermal Reservoirs Using Resistivity |  

Open Energy Info (EERE)

Characterization of Fractures in Geothermal Reservoirs Using Resistivity Characterization of Fractures in Geothermal Reservoirs Using Resistivity Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Paper: Characterization of Fractures in Geothermal Reservoirs Using Resistivity Abstract The optimal design of production in fractured geothermal reservoirs requires knowledge of the resource's connectivity, therefore making fracture characterization highly important. This study aims to develop methodologies to use resistivity measurements to infer fracture properties in geothermal fields. The resistivity distribution in the field can be estimated by measuring potential differences between various points and the data can then be used to infer fracture properties due to the contrast in resistivity between water and rock.

268

Estimating fracture apertures from hydraulic data and comparison with theory  

DOE Green Energy (OSTI)

Estimates of fracture openings, or apertures, were made for massive hydraulic fracture experiments at the Hot Dry Rock geothermal reservoir at Fenton Hill, New Mexico. The basis of these estimates is that if the injection rate is suddenly increased during fracturing, and the subsequent pressure increase to sustain this additional flow is measured, then the pressure increase must be related to the fracture aperture. More detailed considerations indicate that the fracture aperture estimated in this manner is affected by the nature of the fracture geometry, its propagation distance, and its viscous characteristics, but these effects are surprisingly unimportant. The result is a reasonably accurate aperture estimate, which considering the elusive nature of this measurement by other means, is quite satisfactory. These estimates are in good agreement with the fracturing theory of Geertsma and de Klerk. 10 refs., 6 figs.

Dash, Z.V.; Murphy, H.D.

1985-01-01T23:59:59.000Z

269

Application of a 3D hydraulic-fracturing simulator for design of acid-fracturing treatments  

Science Conference Proceedings (OSTI)

Field experience during 1989--90 shows that application of a 3D hydraulic-fracturing simulator increases success of acid-fracturing well treatments. Fracture extension can be limited to the oil-bearing pay, maximum lateral extension can be realized within the height constraint, and acid/rock contact time can be increased by a factor of between 3 and 30. Oil-production response can be improved over other stimulation designs while water-production response can be limited. These methods have been applied in mature waterfloods of the Permian Basin and Cedar Creek anticline.

Morgenthaler, L.N. (Shell Development Co., Houston, TX (United States))

1994-02-01T23:59:59.000Z

270

Field fracturing multi-sites project. Annual report, August 1, 1995--July 31, 1996  

Science Conference Proceedings (OSTI)

The objective of the Field Fracturing Multi-Sites Project (M-Site) is to conduct experiments to definitively determine hydraulic fracture dimensions using remote well and treatment well diagnostic techniques. In addition, experiments are to be conducted to provide data that will resolve significant unknowns with regard to hydraulic fracture modeling, fracture fluid rheology and fracture treatment design. These experiments will be supported by a well-characterized subsurface environment, as well as surface facilities and equipment conducive to acquiring high-quality data. The primary Project goal is to develop a fully characterized, tight reservoir-typical, field-scale hydraulic fracturing test site to diagnose, characterize, and test hydraulic fracturing technology and performance. It is anticipated that the research work being conducted by the multi-disciplinary team of GRI and DOE contractors will lead to the development of a commercial fracture mapping tool/service.

NONE

1996-12-31T23:59:59.000Z

271

A PKN Hydraulic Fracture Model Study and Formation Permeability Determination  

E-Print Network (OSTI)

Hydraulic fracturing is an important method used to enhance the recovery of oil and gas from reservoirs, especially for low permeability formations. The distribution of pressure in fractures and fracture geometry are needed to design conventional and unconventional hydraulic fracturing operations, fracturing during water-flooding of petroleum reservoirs, shale gas, and injection/extraction operation in a geothermal reservoir. Designing a hydraulic fracturing job requires an understanding of fracture growth as a function of treatment parameters. There are various models used to approximately define the development of fracture geometry, which can be broadly classified into 2D and 3D categories. 2D models include, the Perkins-Kern-Nordgren (PKN) fracture model, and the Khristianovic-Geertsma-de. Klerk (KGD) fracture model, and the radial model. 3D models include fully 3D models and pseudo-three-dimensional (P-3D) models. The P-3D model is used in the oil industry due to its simplification of height growth at the wellbore and along the fracture length in multi-layered formations. In this research, the Perkins-Kern-Nordgren (PKN) fracture model is adopted to simulate hydraulic fracture propagation and recession, and the pressure changing history. Two different approaches to fluid leak-off are considered, which are the classical Carter's leak-off theory with a constant leak-off coefficient, and Pressure-dependent leak-off theory. Existence of poroelastic effect in the reservoir is also considered. By examining the impact of leak-off models and poroelastic effects on fracture geometry, the influence of fracturing fluid and rock properties, and the leak-off rate on the fracture geometry and fracturing pressure are described. A short and wide fracture will be created when we use the high viscosity fracturing fluid or the formation has low shear modulus. While, the fracture length, width, fracturing pressure, and the fracture closure time increase as the fluid leak-off coefficient is decreased. In addition, an algorithm is developed for the post-fracture pressure-transient analysis to calculate formation permeability. The impulse fracture pressure transient model is applied to calculate the formation permeability both for the radial flow and linear fracture flow assumption. Results show a good agreement between this study and published work.

Xiang, Jing

2011-12-01T23:59:59.000Z

272

Experimentally determined rock-fluid interactions applicable to a natural hot-dry-rock geothermal system  

DOE Green Energy (OSTI)

The field program cnsists of experiments in which hot rock of low permeability is hydraulically fractured between two wellbores. Water is circulated from one well to the other through the fractured hot rock. Our field experiments are designed to test reservoir engineering parameters such as heat-extraction rates, water-loss rates, flow characteristics including impedance and buoyancy, seismic activity, and fluid chemistry. Laboratory experiments were designed to provide information on the mineral-water reactivity encountered during the field program. Two experimental circulation systems tested the rates of dissolution and alteration during dynamic flow. Solubility of rock in agitated systems was studied. Moreover, pure minerals, samples of the granodiorite from the actual reservoir, and Tijeras Canyon granite have been reacted with distilled water and various solutions of NaCl, NaOH, and Na/sub 2/CO/sub 3/. The results of these experimental systems are compared to the observations made in field experiments done within the hot dry rock reservoir at a depth of approximately 3 km where the initial rock temperature was 150 to 200/sup 0/C.

Charles, R.W.; Grigsby, C.O.; Holley, C.E. Jr.; Tester, J.W.; Blatz, L.A.

1981-01-01T23:59:59.000Z

273

Reservoir modeling of the Phase II Hot Dry Rock System  

DOE Green Energy (OSTI)

The Phase II system has been created with a series of hydraulic fracturing experiments at the Fenton Hill Hot Dry Rock site. Experiment 2032, the largest of the fracturing operations, involved injecting 5.6 million gallons (21,200m/sup 3/) of water into wellbore EE-2 over the period December 6-9, 1983. The experiment has been modeled using geothermal simulator FEHM developed at Los Alamos National Laboratory. The modeling effort has produced strong evidence of a large highly fractured reservoir. Two long term heat extraction schemes for the reservoir are studied with the model.

Zyvoloski, G.

1984-01-01T23:59:59.000Z

274

Corporation Commission Hydraulic FracturingHydraulic Fracturing  

E-Print Network (OSTI)

Corporation Commission Hydraulic FracturingHydraulic Fracturing Joint Committee on Energy Commission What is Hydraulic Fracturing d H D It W k?and How Does It Work? · Stimulates a well to increase by Stanolind Oil Company. 2 #12;Kansas Corporation Commission Are Hydraulic Fracture Jobs Performed in Kansas

Peterson, Blake R.

275

On the Dynamics of Equatorial Subsurface Countercurrents  

Science Conference Proceedings (OSTI)

The equatorial subsurface countercurrents (SSCC are strong, steady, geostrophically balanced eastward flows situated below the high speed core of the Equatorial Undercurrent (EUC) at 3–5°N and S. The dynamics of these currents are explored using ...

Michael J. McPhaden

1984-07-01T23:59:59.000Z

276

Fracture Propagation and Permeability Change under Poro-thermoelastic Loads & Silica Reactivity in Enhanced Geothermal Systems  

SciTech Connect

Geothermal energy is recovered by circulating water through heat exchange areas within a hot rock mass. Geothermal reservoir rock masses generally consist of igneous and metamorphic rocks that have low matrix permeability. Therefore, cracks and fractures play a significant role in extraction of geothermal energy by providing the major pathways for fluid flow and heat exchange. Therefore, knowledge of the conditions leading to formation of fractures and fracture networks is of paramount importance. Furthermore, in the absence of natural fractures or adequate connectivity, artificial fractures are created in the reservoir using hydraulic fracturing. Multiple fractures are preferred because of the large size necessary when using only a single fracture. Although the basic idea is rather simple, hydraulic fracturing is a complex process involving interactions of high pressure fluid injections with a stressed hot rock mass, mechanical interaction of induced fractures with existing natural fractures, and the spatial and temporal variations of in-situ stress. As a result, it is necessary to develop tools that can be used to study these interactions as an integral part of a comprehensive approach to geothermal reservoir development, particularly enhanced geothermal systems. In response to this need we have developed advanced poro-thermo-chemo-mechanical fracture models for rock fracture research in support of EGS design. The fracture propagation models are based on a regular displacement discontinuity formulation. The fracture propagation studies include modeling interaction of induced fractures. In addition to the fracture propagation studies, two-dimensional solution algorithms have been developed and used to estimate the impact of pro-thermo-chemical processes on fracture permeability and reservoir pressure. Fracture permeability variation is studied using a coupled thermo-chemical model with quartz reaction kinetics. The model is applied to study quartz precipitation/dissolution, as well as the variation in fracture aperture and pressure. Also, a three-dimensional model of injection/extraction has been developed to consider the impact poro- and thermoelastic stresses on fracture slip and injection pressure. These investigations shed light on the processes involved in the observed phenomenon of injection pressure variation (e.g., in Coso), and allow the assessment of the potential of thermal and chemical stimulation strategies.

Ahmad Ghassemi

2009-10-01T23:59:59.000Z

277

Fracture characterization study  

DOE Green Energy (OSTI)

First, the origin, nature, and significance of fractures in general are discussed. Next, discussions are directed toward the designation and classification of fractures. Some typical fracture measurement techniques are discussed. Finally, geothermal fracture systems are investigated and correlations made to determine which fracture technologies from oil field work are applicable to geothermal systems. (MHR)

Kehrman, R.F.

1978-04-01T23:59:59.000Z

278

Self-potential observations during hydraulic fracturing  

SciTech Connect

The self-potential (SP) response during hydraulic fracturing of intact Sierra granite was investigated in the laboratory. Excellent correlation of pressure drop and SP suggests that the SP response is created primarily by electrokinetic coupling. For low pressures, the variation of SP with pressure drop is linear, indicating a constant coupling coefficient (Cc) of -200 mV/MPa. However for pressure drops >2 MPa, the magnitude of the Cc increases by 80% in an exponential trend. This increasing Cc is related to increasing permeability at high pore pressures caused by dilatancy of micro-cracks, and is explained by a decrease in the hydraulic tortuosity. Resistivity measurements reveal a decrease of 2% prior to hydraulic fracturing and a decrease of {approx}35% after fracturing. An asymmetric spatial SP response created by injectate diffusion into dilatant zones is observed prior to hydraulic fracturing, and in most cases this SP variation revealed the impending crack geometry seconds before failure. At rupture, injectate rushes into the new fracture area where the zeta potential is different than in the rock porosity, and an anomalous SP spike is observed. After fracturing, the spatial SP distribution reveals the direction of fracture propagation. Finally, during tensile cracking in a point load device with no water flow, a SP spike is observed that is caused by contact electrification. However, the time constant of this event is much less than that for transients observed during hydraulic fracturing, suggesting that SP created solely from material fracture does not contribute to the SP response during hydraulic fracturing.

Moore, Jeffrey R.; Glaser, Steven D.

2007-09-13T23:59:59.000Z

279

ASSEMBLAGES ON WASTE ROCK  

E-Print Network (OSTI)

Abstract: Natural regeneration on waste rock was investigated at the old Wangaloa coal mine, south-east Otago. A 450-m long waste rock stack had been created 40–50 years ago, and has had little anthropogenic intervention since. The stack is made up of a gradient of three main waste rock types, defined as ‘silt-rich’, ‘mixed’, and ‘quartz-rich’, which reflect different proportions of loess siltstone and quartz gravel conglomerate. Plant species assemblages were quantified in four 5-m 2 quadrats in each waste rock type. Invertebrates were heat extracted from substrate cores (7 cm diameter; depth 5 cm) collected from quadrats over an eight-week period in spring 2003. Ordination analysis showed statistically distinct plant and invertebrate assemblages had arisen on each waste rock type. Revegetation patterns were dominated by native, woody individuals on all waste rock types, particularly manuka (Leptospermum scoparium) and kanuka (Kunzea ericoides). Plant cover on ‘silt-rich ’ waste rock was four-fold that on ‘quartz-rich ’ waste rock. Total numbers of invertebrates were highest on ‘quartz-rich’ waste rock, but richness greatest on ‘silt-rich ’ waste rock. Collembola dominated the fauna but their numbers were proportionally greatest in poorly vegetated areas. Further work is required to explain the absence of plants and invertebrates from local areas of waste rock. ___________________________________________________________________________________________________________________________________

C. G. Rufaut; S. Hammit; D. Craw; S. G. Clearwater

2006-01-01T23:59:59.000Z

280

Application of microseismic technology to hydraulic fracture diagnostics: GRI/DOE Field Fracturing Multi-Sites Project  

SciTech Connect

The objective of the Field Fracturing Multi-Sites Project (M-Site) is to conduct field experiments and analyze data that will result in definitive determinations of hydraulic fracture dimensions using remote well and treatment well diagnostic techniques. In addition, experiments will be conducted to provide data that will resolve significant unknowns with regard to hydraulic fracture modeling, fracture fluid rheology and fracture treatment design. These experiments will be supported by a well-characterized subsurface environment as well as surface facilities and equipment conducive to acquiring high-quality data. It is anticipated that the project`s research advancements will provide a foundation for a fracture diagnostic service industry and hydraulic fracture optimization based on measured fracture response. The M-Site Project is jointly sponsored by the Gas Research Institute (GRI) and the US Department of Energy (DOE). The site developed for M-Site hydraulic fracture experimentation is the former DOE Multiwell Experiment (MWX) site located near Rifle, Colorado. The MWX project drilled three closely-spaced wells (MWX-1, MWX-2 and MWX-3) which were the basis for extensive reservoir analyses and tight gas sand characterizations in the blanket and lenticular sandstone bodies of the Mesaverde Group. The research results and background knowledge gained from the MWX project are directly applicable to research in the current M-Site Project.

Wilmer, R. [CER Corp., Las Vegas, NV (United States); Warpinski, N.R. [Sandia National Laboratories (United States); Wright, T.B. [Resources Engineering Systems (United States); Branagan, P.T. [Branagan & Associates (United States); Fix, J.E. [Fix & Associates (United States)

1995-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Integrated Outcrop and Subsurface Studies of the Interwell Environment of Carbonate Reservoirs: Clear Fork (Leonaradian Age) Reservoirs, West Texas and New Mexico  

SciTech Connect

The major goal of this project was to evaluate the impact of fracture porosity on performance of the South Wasson Clear Fork reservoir. The approach was to use subcritical crack (SCC) index measurements and a crack-growth simulator to model potential fracture geometries in this reservoir. The SCC index on representative rock samples and proceedings with other pertinent rock measurements were measured. An approach for modeling coupled matrix and fracture flow using nonneighbor connections in a traditional finite-difference simulator was tested and found to be feasible.

Philip, Zeno; Jennings, Jr., James W.

2001-05-08T23:59:59.000Z

282

Mapping Fractures In The Medicine Lake Geothermal System | Open Energy  

Open Energy Info (EERE)

Fractures In The Medicine Lake Geothermal System Fractures In The Medicine Lake Geothermal System Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Paper: Mapping Fractures In The Medicine Lake Geothermal System Details Activities (1) Areas (1) Regions (0) Abstract: A major challenge to energy production in the region has been locating high-permability fracture zones in the largely impermeable volcanic host rock. An understanding of the fracture networks will be a key to harnessing geothermal resources in the Cascades Author(s): Steven Clausen, Michal Nemcok, Joseph Moore, Jeffrey Hulen, John Bartley Published: GRC, 2006 Document Number: Unavailable DOI: Unavailable Core Analysis At Medicine Lake Area (Clausen Et Al, 2006) Medicine Lake Geothermal Area Retrieved from "http://en.openei.org/w/index.php?title=Mapping_Fractures_In_The_Medicine_Lake_Geothermal_System&oldid=388927

283

Numerical Modeling of Hydraulic Fracture Propagation Using Thermo-hydro-mechanical Analysis with Brittle Damage Model by Finite Element Method  

E-Print Network (OSTI)

Better understanding and control of crack growth direction during hydraulic fracturing are essential for enhancing productivity of geothermal and petroleum reservoirs. Structural analysis of fracture propagation and impact on fluid flow is a challenging issue because of the complexity of rock properties and physical aspects of rock failure and fracture growth. Realistic interpretation of the complex interactions between rock deformation, fluid flow, heat transfer, and fracture propagation induced by fluid injection is important for fracture network design. In this work, numerical models are developed to simulate rock failure and hydraulic fracture propagation. The influences of rock deformation, fluid flow, and heat transfer on fracturing processes are studied using a coupled thermo-hydro-mechanical (THM) analysis. The models are used to simulate microscopic and macroscopic fracture behaviors of laboratory-scale uniaxial and triaxial experiments on rock using an elastic/brittle damage model considering a stochastic heterogeneity distribution. The constitutive modeling by the energy release rate-based damage evolution allows characterizing brittle rock failure and strength degradation. This approach is then used to simulate the sequential process of heterogeneous rock failures from the initiation of microcracks to the growth of macrocracks. The hydraulic fracturing path, especially for fractures emanating from inclined wellbores and closed natural fractures, often involves mixed mode fracture propagation. Especially, when the fracture is inclined in a 3D stress field, the propagation cannot be modeled using 2D fracture models. Hence, 2D/3D mixed-modes fracture growth from an initially embedded circular crack is studied using the damage mechanics approach implemented in a finite element method. As a practical problem, hydraulic fracturing stimulation often involves fluid pressure change caused by injected fracturing fluid, fluid leakoff, and fracture propagation with brittle rock behavior and stress heterogeneities. In this dissertation, hydraulic fracture propagation is simulated using a coupled fluid flow/diffusion and rock deformation analysis. Later THM analysis is also carried out. The hydraulic forces in extended fractures are solved using a lubrication equation. Using a new moving-boundary element partition methodology (EPM), fracture propagation through heterogeneous media is predicted simply and efficiently. The method allows coupling fluid flow and rock deformation, and fracture propagation using the lubrication equation to solve for the fluid pressure through newly propagating crack paths. Using the proposed model, the 2D/3D hydraulic fracturing simulations are performed to investigate the role of material and rock heterogeneity. Furthermore, in geothermal and petroleum reservoir design, engineers can take advantage of thermal fracturing that occurs when heat transfers between injected flow and the rock matrix to create reservoir permeability. These thermal stresses are calculated using coupled THM analysis and their influence on crack propagation during reservoir stimulation are investigated using damage mechanics and thermal loading algorithms for newly fractured surfaces.

Min, Kyoung

2013-08-01T23:59:59.000Z

284

Fractured Geothermal Growth Induced by Heat Extraction  

SciTech Connect

Field testing of a hydraulically stimulated, hot dry rock (HDR) geothermal system at the Fenton Hill site in northern New Mexico indicated that significant reservoir growth occurred as energy was extracted. Tracer, microseismic, and geochemical measurements provided the primary quantitative evidence for the increases in accessible reservoir volume and fractured rock surface area that were observed during energy extraction operations that caused substantial thermal drawdown in portions of the reservoir. These temporal increases suggest that augmentation of reservoir hear-production capacity in an HDR system may be possible. [DJE 2005

Tester, J.W.; Murphy, H.D.; Grigsby, C.O.; Potter, R.M.; Robinson, B.A.

1989-02-01T23:59:59.000Z

285

Geomechanical Development of Fractured Reservoirs During Gas Production  

E-Print Network (OSTI)

Within fractured reservoirs, such as tight gas reservoir, coupled processes between matrix deformation and fluid flow are very important for predicting reservoir behavior, pore pressure evolution and fracture closure. To study the coupling between gas desorption and rock matrix/fracture deformation, a poroelastic constitutive relation is developed and used for deformation of gas shale. Local continuity equation of dry gas model is developed by considering the mass conservation of gas, including both free and absorbed phases. The absorbed gas content and the sorption-induced volumetric strain are described through a Langmiur-type equation. A general porosity model that differs from other empirical correlations in the literature is developed and utilized in a finite element model to coupled gas diffusion and rock mass deformation. The dual permeability method (DPM) is implemented into the Finite Element Model (FEM) to investigate fracture deformation and closure and its impact on gas flow in naturally fractured reservoir. Within the framework of DPM, the fractured reservoir is treated as dual continuum. Two independent but overlapping meshes (or elements) are used to represent these kinds of reservoirs: one is the matrix elements used for deformation and fluid flow within matrix domain; while the other is the fracture element simulating the fluid flow only through the fractures. Both matrix and fractures are assumed to be permeable and can accomodate fluid transported. A quasi steady-state function is used to quantify the flow that is transferred between rock mass and fractures. By implementing the idea of equivalent fracture permeability and shape-factor within the transfer function into DPM, the fracture geometry and orientation are numerically considered and the complexity of the problem is well reduced. Both the normal deformation and shear dilation of fractures are considered and the stress-dependent fracture aperture can be updated in time. Further, a non-linear numerical model is constructed by implementing a poroviscoelastic model into the dual permeability (DPM)-finite element model (FEM) to investigate the coupled time-dependent viscoelastic deformation, fracture network evolution and compressible fluid flow in gas shale reservoir. The viscoelastic effect is addressed in both deviatoric and symmetric effective stresses to emphasize the effect of shear strain localization on fracture shear dilation. The new mechanical model is first verified with an analytical solution in a simple wellbore creep problem and then compared with the poroelastic solution in both wellbore and field cases.

Huang, Jian

2013-05-01T23:59:59.000Z

286

Recent developments in the hot dry rock geothermal energy program  

DOE Green Energy (OSTI)

In recent years, most of the Hot Dry Rock Programs effort has been focused on the extraction technology development effort at the Fenton Hill test site. The pair of approximately 4000 m wells for the Phase II Engineering System of the Fenton Hill Project have been completed. During the past two years, hydraulic fracture operations have been carried out to develop the geothermal reservoir. Impressive advances have been made in fracture identification techniques and instrumentation. To develop a satisfactory interwellbore flow connection the next step is to redrill the lower section of one of the wells into the fractured region. Chemically reactive tracer techniques are being developed to determine the effective size of the reservoir area. A new estimate has been made of the US hot dry rock resource, based upon the latest geothermal gradiant data. 3 figs.

Franke, P.R.; Nunz, G.J.

1985-01-01T23:59:59.000Z

287

Pistol-packin' rock bit shoots its way to TD (total depth)  

Science Conference Proceedings (OSTI)

Tround International Inc. and Dresser Industries are developing a drill bit that fires ceramic bullets to fracture the rock ahead of it. Initial testing shows it to increase penetration rates through hard formations by 200 to 400%. It incorporates an open chamber system and fires 3 ceramic projectiles per salvo into the rock face at intervals staggered by milliseconds to create overlapping stress waves. Upon impact the ceramic bullets disintegrate and do not interfere with drilling efficiency of the bit cones. The stress waves fracture the rock one or more feet ahead of the drill.

Booker, C.H.

1982-05-01T23:59:59.000Z

288

Hot dry rock geothermal heat extraction  

DOE Green Energy (OSTI)

A man-made geothermal reservoir has been created at a depth of 2.7 km in hot, dry granite by hydraulic fracturing. The system was completed by directionally drilling a second well in close proximity with the top of the vertical fracture. In early 1978 heat was extracted from this reservoir for a period of 75 days. During this period thermal power was produced at an average rate of 4 MW(t). Theoretical analysis of th measured drawdown suggests a total fracture heat transfer area of 16,000 m/sup 2/. Viscous impedance to through-flow declined continuously so that at the end of the experiment this impedance was only one-fifth its initial value. Water losses to the surrounding rock formation also decreased continuously, and eventually this loss rate was less than 1% of the circulated flow rate. Geochemical analyses suggest that, with scale up of the heat transfer area and deeper, hotter reservoirs, hot dry rock reservoirs can ultimately produce levels of power on a commercial scale.

Murphy, H.D.

1979-01-01T23:59:59.000Z

289

Los Alamos hot dry rock geothermal project  

DOE Green Energy (OSTI)

The greatest potential for geothermal energy is the almost unlimited energy contained in the vast regions of hot, but essentially impermeable, rock within the first six or seven km of the Earth's crust. For the past five years, the Los Alamos Scientific Laboratory has been investigating and developing a practical, economical and environmentally acceptable method of extracting this energy. By early 1978, a 10 MW (thermal) heat extraction experiment will be in operation. In the Los Alamos concept, a man-made geothermal reservoir is formed by drilling into a region of suitably hot rock, and then creating within the rock a very large surface for heat transfer by large-scale hydraulic-fracturing techniques. After a circulation loop is formed by drilling a second hole to intersect the fractured region, the heat contained in this reservoir is brought to the surface by the buoyant closed-loop circulation of water. The water is kept liquid throughout the loop by pressurization, thereby increasing the rate of heat transport up the withdrawal hole compared to that possible with steam.

Brown, D.W.; Pettitt, R.A.

1977-01-01T23:59:59.000Z

290

Collaborative multi-agent rock facies classification from wireline well log data  

Science Conference Proceedings (OSTI)

Gas and oil reservoirs have been the focus of modeling efforts for decades as an attempt to locate zones with high volumes. Certain subsurface layers and layer sequences, such as those containing shale, are known to be impermeable to gas and/or liquid. ... Keywords: Applied artificial intelligence, Collaborative learning, Multi-agent systems, Rock classification, Well logs

Christopher M. Gifford; Arvin Agah

2010-10-01T23:59:59.000Z

291

SUBSURFACE REPOSITORY INTEGRATED CONTROL SYSTEM DESIGN  

Science Conference Proceedings (OSTI)

The purpose of this document is to develop preliminary high-level functional and physical control system architectures for the proposed subsurface repository at Yucca Mountain. This document outlines overall control system concepts that encompass and integrate the many diverse systems being considered for use within the subsurface repository. This document presents integrated design concepts for monitoring and controlling the diverse set of subsurface operations. The subsurface repository design will be composed of a series of diverse systems that will be integrated to accomplish a set of overall functions and objectives. The subsurface repository contains several Instrumentation and Control (I&C) related systems including: waste emplacement systems, ventilation systems, communication systems, radiation monitoring systems, rail transportation systems, ground control monitoring systems, utility monitoring systems (electrical, lighting, water, compressed air, etc.), fire detection and protection systems, retrieval systems, and performance confirmation systems. Each of these systems involve some level of I&C and will typically be integrated over a data communication network. The subsurface I&C systems will also integrate with multiple surface-based site-wide systems such as emergency response, health physics, security and safeguards, communications, utilities and others. The scope and primary objectives of this analysis are to: (1) Identify preliminary system level functions and interface needs (Presented in the functional diagrams in Section 7.2). (2) Examine the overall system complexity and determine how and on what levels these control systems will be controlled and integrated (Presented in Section 7.2). (3) Develop a preliminary subsurface facility-wide design for an overall control system architecture, and depict this design by a series of control system functional block diagrams (Presented in Section 7.2). (4) Develop a series of physical architectures that present preliminary concepts for integrating the diverse set of control systems to be used within the subsurface repository facility (Presented in Section 7.3). (5) Develop initial concepts for an overall subsurface data communication system that can be used to integrate critical and data-intensive control systems (Presented in Section 7.4). (6) Discuss technology trends and control system design issues (Presented in Section 7.5).

C.J. Fernado

1998-09-17T23:59:59.000Z

292

Technical Protocols for Assessing Dense Non-Aqueous Phase Liquid Mobility in the Subsurface at Manufactured Gas Plant Sites  

Science Conference Proceedings (OSTI)

This report summarizes Electric Power Research Institute (EPRI) research that has been conducted on dense non-aqueous phase liquid (DNAPL) mobility at manufactured gas plant (MGP) sites and presents technical protocols for conducting DNAPL mobility assessments at MGP sites using currently available methodologies and/or technologies. The technical protocols address each of the primary zones of the subsurface environment: vadose zone, saturated zone, and bedrock (both competent and fractured). The report a...

2011-12-12T23:59:59.000Z

293

Gas Permeability of Fractured Sandstone/Coal Samples under Variable Confining Pressure  

E-Print Network (OSTI)

argillite under con?nement: gas and water testing. Phys.Gascoyne, M. , Wuschke, D.M. : Gas migration through water-fractured rock: results of a gas injection test. J.

Liu, Weiqun; Li, Yushou; Wang, Bo

2010-01-01T23:59:59.000Z

294

Fracture Mapping in the Soultz-sous-Forets Geothermal Field from Microearthquake Relocation  

E-Print Network (OSTI)

In 2003, a massive hydraulic fracturing experiment was carried out at the European Geothermal Hot Dry Rock site at Soultz-sous-Forêts, France. The two week injection of water generated a high level of microseismic activity. ...

Michelet, Sophie

2006-01-01T23:59:59.000Z

295

Linear Elastic Fracture Mechanics  

Science Conference Proceedings (OSTI)

..., ASM International, 1996, p 371â??380ASM Handbook, Vol 19, Fatigue And FractureS.D. Antolovich and B.F. Antolovich, An Introduction to Fracture

296

Limitations of rock mechanics in energy-resource recovery and development  

DOE Green Energy (OSTI)

Rock-mechanics problems which limit energy-resource recovery and development are assessed. The most serious limitations were found in the fields of geothermal exploration, mining and in-situ recovery, nuclear-waste disposal, oil and gas recovery, underground storage, and under-ocean tunneling. Recommendations include research to determine and predict porosity, permeability, and fluid flow in situ; research to develop better methods for determining and obtaining shallow and deep in situ stresses; research to improve the ability to map fracture patterns, particularly major fractures and faults, at depth; research to improve the understanding of rock-fragmentation processes for increasing the effectiveness of drilling and excavation systems; research to increase understanding of the relation of laboratory-measured quantities to in situ conditions; and research to provide the thermophysical and thermomechanical properties of rock, including fractured rock. (JRD)

Not Available

1978-04-14T23:59:59.000Z

297

Characterization of hot dry rock geothermal energy extraction systems  

DOE Green Energy (OSTI)

The engineering of heat exchange systems by which geothermal heat can be efficiently extracted from hot impermeable rocks is studied. The system currently under investigation at Fenton Hill, New Mexico consists of a network of large fractures created through the hydraulic pressurization of a well penetrating hot basement rocks and subsequently intersected by a second well drilled to form a flow-thru system. Cool water pumped into the fractures through one well, once heated in the reservoir, returns to the surface through the second well, is cooled, and then recirculated. While much is known about the performance parameters of the fracture network from short-term flow tests, little is understood concerning the spatial dimensions and geometrical relationship of individual fractures comprising the network. Ultimately, the success one has in estimating the long-term performance of such a system where commercialization is an issue, and in engineering future systems with optimal performance, depends on the success in characterizing the flow-thru fracture networks. To date only nonconventional application of oil field logging techniques and acoustic emissions studies have been used in the characterization of the fracture network.

Albright, J.N.; Newton, C.A.

1981-01-01T23:59:59.000Z

298

Subsurface Science (The Molecular Environmental Science Group) |  

NLE Websites -- All DOE Office Websites (Extended Search)

Subsurface Science Subsurface Science BIO Home Page About BIO News Releases Research Publications People Contact Us Organization Chart Site Index Inside BIO BIO Safety About Argonne arrow Subsurface Science The Molecular Environmental Science Group (MESG) The MESG is part of the Biosciences Division at Argonne National Laboratory. One of the main foci during the creation and growth of the MESG has been the development of an internationally recognized integrated multidisciplinary scientific team focused on the investigation of fundamental biogeochemical questions. Presently, expertise that is represented by members of the MES Group includes x-ray Physics, Environmental Chemistry, Environmental Microbiology, (Bio)geochemistry, and radiolimnology. Additional expertise in electron microscopy, x-ray microscopy, Microbial Ecology, and Bioinformatics often is provided by collaborations with scientists outside of our group.

299

MSTS - Multiphase Subsurface Transport Simulator theory manual  

SciTech Connect

The US Department of Energy, through the Yucca Mountain Site Characterization Project Office, has designated the Yucca Mountain site in Nevada for detailed study as the candidate US geologic repository for spent nuclear fuel and high-level radioactive waste. Site characterization will determine the suitability of the Yucca Mountain site for the potential waste repository. If the site is determined suitable, subsequent studies and characterization will be conducted to obtain authorization from the Nuclear Regulatory Commission to construct the potential waste repository. A principal component of the characterization and licensing processes involves numerically predicting the thermal and hydrologic response of the subsurface environment of the Yucca Mountain site to the potential repository over a 10,000-year period. The thermal and hydrologic response of the subsurface environment to the repository is anticipated to include complex processes of countercurrent vapor and liquid migration, multiple-phase heat transfer, multiple-phase transport, and geochemical reactions. Numerical simulators based on mathematical descriptions of these subsurface phenomena are required to make numerical predictions of the thermal and hydrologic response of the Yucca Mountain subsurface environment The engineering simulator called the Multiphase Subsurface Transport Simulator (MSTS) was developed at the request of the Yucca Mountain Site Characterization Project Office to produce numerical predictions of subsurface flow and transport phenomena at the potential Yucca Mountain site. This document delineates the design architecture and describes the specific computational algorithms that compose MSTS. Details for using MSTS and sample problems are given in the {open_quotes}User`s Guide and Reference{close_quotes} companion document.

White, M.D.; Nichols, W.E.

1993-05-01T23:59:59.000Z

300

Mathematical modeling of hydraulic fracturing in coal seams  

Science Conference Proceedings (OSTI)

Hydraulic fracturing of coal seam is considered as a process of development of discontinuities in rock mass elements due to change in hydrogeomechanical situation on filtration of fluid under pressure. Failure is associated with excess of the effective stresses over the rock tension strength. The problem on filtration and failure of massif is solved by the finite-element method using the procedure of fictitious nodal forces.

Olovyanny, A.G. [All Russian Science Research Institute for Mine Surveying, St. Petersburg (Russian Federation)

2005-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Induction heaters used to heat subsurface formations  

DOE Patents (OSTI)

A heating system for a subsurface formation includes an elongated electrical conductor located in the subsurface formation. The electrical conductor extends between at least a first electrical contact and a second electrical contact. A ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor. The electrical conductor, when energized with time-varying electrical current, induces sufficient electrical current flow in the ferromagnetic conductor such that the ferromagnetic conductor resistively heats to a temperature of at least about 300.degree. C.

Nguyen, Scott Vinh (Houston, TX); Bass, Ronald M. (Houston, TX)

2012-04-24T23:59:59.000Z

302

Heating systems for heating subsurface formations  

Science Conference Proceedings (OSTI)

Methods and systems for heating a subsurface formation are described herein. A heating system for a subsurface formation includes a sealed conduit positioned in an opening in the formation and a heat source. The sealed conduit includes a heat transfer fluid. The heat source provides heat to a portion of the sealed conduit to change phase of the heat transfer fluid from a liquid to a vapor. The vapor in the sealed conduit rises in the sealed conduit, condenses to transfer heat to the formation and returns to the conduit portion as a liquid.

Nguyen, Scott Vinh (Houston, TX); Vinegar, Harold J. (Bellaire, TX)

2011-04-26T23:59:59.000Z

303

URANIUM IN ALKALINE ROCKS  

E-Print Network (OSTI)

District, Teller County, Colorado," U.S. Geol. Survey Bull.Jamestown District, Colorado," Econ. Geol. , v. 68, pp 1247-Rocks at Powderhorn, Colorado; Economic Geology, Vol. 60,

Murphy, M.

2011-01-01T23:59:59.000Z

304

Storage capacity in hot dry rock reservoirs  

DOE Patents (OSTI)

A method is described for extracting thermal energy, in a cyclic manner, from geologic strata which may be termed hot dry rock. A reservoir comprised of hot fractured rock is established and water or other liquid is passed through the reservoir. The water is heated by the hot rock, recovered from the reservoir, cooled by extraction of heat by means of heat exchange apparatus on the surface, and then re-injected into the reservoir to be heated again. Water is added to the reservoir by means of an injection well and recovered from the reservoir by means of a production well. Water is continuously provided to the reservoir and continuously withdrawn from the reservoir at two different flow rates, a base rate and a peak rate. Increasing water flow from the base rate to the peak rate is accomplished by rapidly decreasing backpressure at the outlet of the production well in order to meet periodic needs for amounts of thermal energy greater than a baseload amount, such as to generate additional electric power to meet peak demands. The rate of flow of water provided to the hot dry rock reservoir is maintained at a value effective to prevent depletion of the liquid inventory of the reservoir. 4 figs.

Brown, D.W.

1997-11-11T23:59:59.000Z

305

Storage capacity in hot dry rock reservoirs  

DOE Patents (OSTI)

A method of extracting thermal energy, in a cyclic manner, from geologic strata which may be termed hot dry rock. A reservoir comprised of hot fractured rock is established and water or other liquid is passed through the reservoir. The water is heated by the hot rock, recovered from the reservoir, cooled by extraction of heat by means of heat exchange apparatus on the surface, and then re-injected into the reservoir to be heated again. Water is added to the reservoir by means of an injection well and recovered from the reservoir by means of a production well. Water is continuously provided to the reservoir and continuously withdrawn from the reservoir at two different flow rates, a base rate and a peak rate. Increasing water flow from the base rate to the peak rate is accomplished by rapidly decreasing backpressure at the outlet of the production well in order to meet periodic needs for amounts of thermal energy greater than a baseload amount, such as to generate additional electric power to meet peak demands. The rate of flow of water provided to the hot dry rock reservoir is maintained at a value effective to prevent depletion of the liquid

Brown, Donald W. (Los Alamos, NM)

1997-01-01T23:59:59.000Z

306

Uranium favorability of tertiary sedimentary rocks of the Pend Oreille River valley, Washington. [Measurement and sampling of surface sections, collection of samples from isolated outcrops, chemical and mineralogical analyses of samples, and examination of available water logs  

SciTech Connect

Tertiary sedimentary rocks in the Pend Oreille River valley were investigated in a regional study to determine the favorability for potential uranium resources of northeastern Washington. This project involved measurement and sampling of surface sections, collection of samples from isolated outcrops, chemical and mineralogical analyses of samples, and examination of available water well logs. The Box Canyon Dam area north of Ione is judged to have very high favorability. Thick-bedded conglomerates interbedded with sandstones and silty sandstones compose the Tiger Formation in this area, and high radioactivity levels are found near the base of the formation. Uranophane is found along fracture surfaces or in veins. Carbonaceous material is present throughout the Tiger Formation in the area. Part of the broad Pend Oreille valley surrounding Cusick, Washington, is an area of high favorability. Potential host rocks in the Tiger Formation, consisting of arkosic sandstones interbedded with radioactive shales, probably extend throughout the subsurface part of this area. Carbonaceous material is present and some samples contain high concentrations of uranium. In addition, several other possible chemical indicators were found. The Tiger-Lost Creek area is rated as having medium favorability. The Tiger Formation contains very hard, poorly sorted granite conglomerate with some beds of arkosic sandstone and silty sandstone. The granite conglomerate was apparently derived from source rocks having relatively high uranium content. The lower part of the formation is more favorable than the upper part because of the presence of carbonaceous material, anomalously high concentrations of uranium, and other possible chemical indicators. The area west of Ione is judged to have low favorability, because of the very low permeability of the rocks and the very low uranium content. (auth)

Marjaniemi, D.K.; Robins, J.W.

1975-08-01T23:59:59.000Z

307

The Study of Permeability Change of Fractal Under Fracturing Basing on Damage Theory  

Science Conference Proceedings (OSTI)

In order to research the evolution of permeability and damage of fractal rock under hydraulic fracturing, a new damage variable that describing relative reduction of pore amounts as radius is bigger than r any fracturing stage is defined. Assuming the ... Keywords: damagey, fracta, permeabilit

Zhao Wanchun; Ai Chi

2010-08-01T23:59:59.000Z

308

Interactive fracture design model  

DOE Green Energy (OSTI)

A computer program is described that can be used to design a fracture stimulation treatment for a geothermal reservoir. The program uses state-of-the-art methods to calculate the temperature of the fracture fluid as a function of time and distance in the fracture. This information is used to determine the temperature dependent properties of the fracture fluid. These fluid properties are utilized to calculate the fracture geometry as a function of time. The fracture geometry and temperature distribution of the fracture fluid are coupled so the subroutines that calculate these distributions have been made interactive.

Not Available

1980-05-01T23:59:59.000Z

309

Real-time and post-frac' 3-D analysis of hydraulic fracture treatments in geothermal reservoirs  

SciTech Connect

Economic power production from Hot Dry Rock (HDR) requires the establishment of an efficient circulation system between wellbores in reservoir rock with extremely low matrix permeability. Hydraulic fracturing is employed to establish the necessary circulation system. Hydraulic fracturing has also been performed to increase production from hydrothermal reservoirs by enhancing the communication with the reservoir's natural fracture system. Optimal implementation of these hydraulic fracturing applications, as with any engineering application, requires the use of credible physical models and the reconciliation of the physical models with treatment data gathered in the field. Analysis of the collected data has shown that 2-D models and 'conventional' 3-D models of the hydraulic fracturing process apply very poorly to hydraulic fracturing in geothermal reservoirs. Engineering decisions based on these more 'conventional' fracture modeling techniques lead to serious errors in predicting the performance of hydraulic fracture treatments. These errors can lead to inappropriate fracture treatment design as well as grave errors in well placement for hydrothermal reservoirs or HDR reservoirs. This paper outlines the reasons why conventional modeling approaches fall short, and what types of physical models are needed to credibly estimate created hydraulic fracture geometry. The methodology of analyzing actual measured fracture treatment data and matching the observed net fracturing pressure (in realtime as well as after the treatment) is demonstrated at two separate field sites. Results from an extensive Acoustic Emission (AE) fracture diagnostic survey are also presented for the first case study aS an independent measure of the actual created hydraulic fracture geometry.

Wright, C.A.; Tanigawa, J.J.; Hyodo, Masami; Takasugi, Shinji

1994-01-20T23:59:59.000Z

310

Session: Hard Rock Penetration  

DOE Green Energy (OSTI)

This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Hard Rock Penetration - Summary'' by George P. Tennyson, Jr.; ''Overview - Hard Rock Penetration'' by James C. Dunn; ''An Overview of Acoustic Telemetry'' by Douglas S. Drumheller; ''Lost Circulation Technology Development Status'' by David A. Glowka; ''Downhole Memory-Logging Tools'' by Peter Lysne.

Tennyson, George P. Jr.; Dunn, James C.; Drumheller, Douglas S.; Glowka, David A.; Lysne, Peter

1992-01-01T23:59:59.000Z

311

A Comprehensive Study Of Fracture Patterns And Densities In The Geysers  

Open Energy Info (EERE)

Study Of Fracture Patterns And Densities In The Geysers Study Of Fracture Patterns And Densities In The Geysers Geothermal Reservoir Using Microearthquake Shear-Wave Splitting Tomography Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: A Comprehensive Study Of Fracture Patterns And Densities In The Geysers Geothermal Reservoir Using Microearthquake Shear-Wave Splitting Tomography Details Activities (1) Areas (1) Regions (0) Abstract: In this project we developed a method for using seismic S-wave data to map the patterns and densities of sub-surface fractures in the NW Geysers Geothermal Field/ (1) This project adds to both the general methods needed to characterize the geothermal production fractures that supply steam for power generation and to the specific knowledge of these in the Geysers area. (2)By locating zones of high fracture density it will be

312

Microearthquakes induced during hydraulic fracturing at the Fenton Hill HDR site: the 1982 experiments  

DOE Green Energy (OSTI)

The on-site real-time processing of microearthquake signals that occur during massive hydraulic fracturing provides a notion of the location and growth of the fracture system being created. This enables quick decisions to be made in regard to the ongoing operations. The analytical results and impact of the hypocenter mapping during the 1982 fracturing experiments in the Fenton Hill Phase II Hot Dry Rock geothermal reservoir are reported.

Keppler, H.; Pearson, C.F.; Potter, R.M.; Albright, J.N.

1983-01-01T23:59:59.000Z

313

Fractured geothermal reservoir growth induced by heat extraction  

DOE Green Energy (OSTI)

Field testing of a hydraulically-stimulated, hot dry rock geothermal system at the Fenton Hill site in northern New Mexico has indicated that significant reservoir growth occurred as energy was extracted. Tracer, microseismic, and geochemical measurements provided the primary quantitative evidence for documenting the increases in accessible reservoir volume and fractured rock surface area that were observed during energy extraction operations which caused substantial thermal drawdown in portions of the reservoir. These temporal increases suggest that augmentation of reservoir heat production capacity in hot dry rock systems may be possible.

Tester, J.W.; Murphy, H.D.; Grigsby, C.O.; Robinson, B.A.; Potter, R.M.

1986-01-01T23:59:59.000Z

314

Rock-ravintolatoiminta : elävää rock-musiikkia ravintolaympäristössä; Rock venue activity : live rock music in the restaurant setting.  

E-Print Network (OSTI)

??Työn tavoitteena oli tutkia rock-ravintolatoimintaa ja elävää rock-musiikkia ravintolaympäristössä ravintolan, artistin ja asiakkaan näkökulmasta. Tutkimuksessa pyrittiin selvittämään rock-ravintolayrittämisen toimintatapoja ja kartoittamaan alan tämän hetkistä tilaa.… (more)

Väyliö, Jari

2006-01-01T23:59:59.000Z

315

The Effect of Proppant Size and Concentration on Hydraulic Fracture Conductivity in Shale Reservoirs  

E-Print Network (OSTI)

Hydraulic fracture conductivity in ultra-low permeability shale reservoirs is directly related to well productivity. The main goal of hydraulic fracturing in shale formations is to create a network of conductive pathways in the rock which increase the surface area of the formation that is connected to the wellbore. These highly conductive fractures significantly increase the production rates of petroleum fluids. During the process of hydraulic fracturing proppant is pumped and distributed in the fractures to keep them open after closure. Economic considerations have driven the industry to find ways to determine the optimal type, size and concentration of proppant that would enhance fracture conductivity and improve well performance. Therefore, direct laboratory conductivity measurements using real shale samples under realistic experimental conditions are needed for reliable hydraulic fracturing design optimization. A series of laboratory experiments was conducted to measure the conductivity of propped and unpropped fractures of Barnett shale using a modified API conductivity cell at room temperature for both natural fractures and induced fractures. The induced fractures were artificially created along the bedding plane to account for the effect of fracture face roughness on conductivity. The cementing material present on the surface of the natural fractures was preserved only for the initial unpropped conductivity tests. Natural proppants of difference sizes were manually placed and evenly distributed along the fracture face. The effect of proppant monolayer was also studied.

Kamenov, Anton

2013-05-01T23:59:59.000Z

316

On relative permeability of rough-walled fractures  

DOE Green Energy (OSTI)

This paper presents a conceptual and numerical model of multiphase flow in fractures. The void space of real rough-walled rock fractures is conceptualized as a two-dimensional heterogeneous porous medium, characterized by aperture as a function of position in the fracture plane. Portions of a fracture are occupied by wetting and non-wetting phase, respectively, according to local capillary pressure and accessibility criteria. Phase occupancy and permeability are derived by assuming a parallel-plate approximation for suitably small subregions in the fracture plane. Wetting and non-wetting phase relative permeabilities are calculated by numerically simulating single phase flows separately in the wetted and non-wetted pore spaces. Illustrative examples indicate that relative permeabilities depend sensitively on the nature and range of spatial correlation between apertures. 30 refs., 7 figs., 1 tab.

Pruess, K.; Tsang, Y.W.

1989-01-01T23:59:59.000Z

317

Proximity functions for modeling fluids and heat flow in reservoirs with stochastic fracture distributions  

DOE Green Energy (OSTI)

Conventional approaches to geothermal reservoir modeling have employed a porous medium approximation, but recently methods have been developed which can take into account the different thermodynamic conditions in rock matrix and fractures. The multiple interacting continua method (MINC) treats the thermal and hydraulic interaction between rock matrix and fractures in terms of a set of geometrical parameters. However, this approach was restricted to idealized fracture distributions with regularly shaped matrix blocks. Fractures in geothermal reservoirs usually occur in nearly parallel sets with a certain scatter in orientation, and a stochastic distribution of spacings and apertures. The MINC-method was extended to realistic fracture systems with stochastic distributions. The interaction between matrix and fractures is parameterized in terms of a proximity function, which represents the volume of matrix rock as a function of distance from the fractures. Monte Carlo techniques were employed to compute proximity functions for a number of two-dimensional systems with regular or stochastic fracture distributions. It is shown how the proximity functions can be used to generate computational grids for modeling fluid and heat flow in fractured reservoirs.

Pruess, K.; Karasaki, K.

1982-10-01T23:59:59.000Z

318

Energy extraction characteristics of hot dry rock geothermal systems  

DOE Green Energy (OSTI)

The LASL Hot Dry Rock Geothermal Energy Project is investigating methods to extract energy at useful temperatures and rates from naturally heated crustal rock in locations where the rock does not spontaneously yield natural steam or hot water at a rate sufficient to support commercial utilization. Several concepts are discussed for application to low and high permeability formations. The method being investigated first is intended for use in formations of low initial permeability. It involves producing a circulation system within the hot rock by hydraulic fracturing to create a large crack connecting two drilled holes, then operating the system as a closed pressurized-water heat-extration loop. With the best input assumptions that present knowledge provides, the fluid-flow and heat-exchange calculations indicate that unpumped (buoyant) circulation through a large hydraulic fracture can maintain a commercially useful rate of heat extraction throughout a usefully long system life. With a power cycle designed for the temperature of the fluid produced, total capital investment and generating costs are estimated to be at least competitive with those of fossil-fuel-fired and nuclear electric plants. This paper discusses the potential of the hot dry rock resource, various heat extraction concepts, prediction of reservoir performance, and economic factors, and summarizes recent progress in the LASL field program.

Tester, J.W.; Smith, M.C.

1977-01-01T23:59:59.000Z

319

Los Alamos hot-dry-rock project: recent results  

DOE Green Energy (OSTI)

A new deeper reservoir is presently being investigated at the Laboratory's Fenton Hill Hot Dry Rock (HDR) site. The region surrounding the lower of two inclined boreholes, directionally-drilled to about 4 km in hot crystalline rock, has been pressurized in a sequence of injection tests. Based primarily on the measurements made by two close-in microseismic detectors, two similar volumetric reservoir regions have been developed by massive hydraulic fracturing, but with no significant hydraulic communication with the upper borehole as yet.

Brown, D.W.

1982-01-01T23:59:59.000Z

320

New observations of infiltration through fractured alluvium in Yucca Flat, Nevada Test Site: A preliminary field investigation  

Science Conference Proceedings (OSTI)

Regional tectonics coupled with the subsurface detonation of nuclear explosives has caused widespread fracturing of the alluvium of Yucca Flat. Fractures deeper than 30 meters have been observed in boreholes. Some of these fractures are large enough to capture significant amounts of runoff during storm events. Evidence of stream capture by fractures and observations of runoff flowing into open fractures give qualitative evidence of infiltration to depths greater than several meters and possibly to the saturated zone. Our field observations contradict the assumption that little infiltration occurs on Yucca Flat. The larger, hydrologically important fractures are associated with geologic faults or the regional stress field. Additional field studies are needed to investigate the impact of fractures on the transport of contaminants.

Kao, C.S. [California Univ., Berkeley, CA (United States). Dept. of Civil Engineering; Smith, D.K. [Lawrence Livermore National Lab., CA (United States); McKinnis, W.B. [Lawrence Livermore National Lab., Mercury, NV (United States)

1994-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Hot Dry Rock at Fenton Hill, USA  

DOE Green Energy (OSTI)

The Hot Dry Rock Geothermal Energy Project began in the early 1970's with the objective of developing a technology to make economically available the large ubiquitous thermal energy of the upper earth crust. The program, operated by the Los Alamos National Laboratory, has been funded by the Department of Energy (and its predecessors) and for a few years with participation by West Germany and Japan. An energy reservoir was accessed by drilling and hydraulically fracturing in the Precambrian basement rock at Fenton Hill, outside the Valles Caldera of north-central New Mexico. Water was circulated through the reservoir (Phase 1, 1978--1980) producing up to 5 MWt at 132/degree/C. A second (Phase 2) reservoir has been established with a deeper pair of holes and an initial flow test completed producing about 10 MWt at 190/degree/C. These accomplishments have been supported and paralleled by developments in drilling, well completion and instrumentation hardware. Acoustic or microseismic fracture mapping and geochemistry studies in addition to hydraulic and thermal data contribute to reservoir analyses. Studies of some of the estimated 430,000 quads of HDR resources in the United States have been made with special attention focused on sites most advantageous for early development. 17 refs., 3 figs., 1 tab.

Hendron, R.H.

1988-01-01T23:59:59.000Z

322

The US Hot Dry Rock project  

DOE Green Energy (OSTI)

The Hot Dry Rock geothermal energy project began in the early 1970's with the objective of developing a technology to make economically available the large ubiquitous thermal energy of the upper earth crust. The program has been funded by the Department of Energy (and its predecessors) and for a few years with participation by West Germany and Japan. An energy reservoir was accessed by drilling and hydraulically fracturing in the precambrian basement rock outside the Valles Caldera of north-central New Mexico. Water was circulated through the reservoir (Phase I, 1978-1980) producing up to 5 MWt at 132/sup 0/C. A second (Phase II) reservoir has been established with a deeper pair of holes and an initial flow test completed producing about 10 MWt at 190/sup 0/C. These accomplishments have been supported and paralleled by developments in drilling, well completion and instrumentation hardware. Acoustic or microseismic fracture mapping and geochemistry studies in addition to hydraulic and thermal data contribute to reservoir analyses. Studies of some of the estimated 430,000 quads of HDR resources in the United States have been made with special attention focused on sites most advantageous for early development.

Hendron, R.H.

1987-01-01T23:59:59.000Z

323

Results of fluid-circulation experiments: LASL hot dry rock geothermal project  

DOE Green Energy (OSTI)

The first large-scale field experiment to investigate the extraction of heat from hot dry rock is now in progress on the Jemez Plateau in northern New Mexico. The experimental system consists of two holes about 3 km deep, from each of which hydraulic fractures have been made. The two major fractures appear to be approximately vertical and parallel, and separated by about 9 m of granodiorite through which fluid is transmitted probably along a distributed set of secondary fractures. Experiments to this point have demonstrated that the surface area of each hydraulic fracture is sufficient to accomplish effective heat transfer from the rock, at about 200/sup 0/C, to water circulated through the system; that there is no significant short-circuiting of the water within the fractures; but that the impedance to fluid flow through the rock between the fractures is too high to permit the rate of heat extraction (initially about 10 MWt) desired of the experimental system. An attempt to reduce impedance by leaching with dilute sodium carbonate solution was unsuccessful. Therefore an attempt is now being made to reduce it by re-drilling from near the bottom of one hole in order to produce a simple system geometry in which the two holes are connected directly through a single hydraulic fracture.

Smith, M.C.

1977-01-01T23:59:59.000Z

324

Oldest Rock on Earth  

NLE Websites -- All DOE Office Websites (Extended Search)

Canada." and "Some of the oldest surface rock can be found in the Canadian Shield, Australia, Africa and in other more specific places around the world. The ages of...

325

Radionuclide Sensors for Subsurface Water Monitoring  

SciTech Connect

Contamination of the subsurface by radionuclides is a persistent and vexing problem for the Department of Energy. These radionuclides must be measured in field studies and monitoed in the long term when they cannot be removed. However, no radionuclide sensors existed for groundwater monitoring prior to this team's research under the EMSP program Detection of a and b decays from radionuclides in water is difficult due to their short ranges in condensed media.

Timothy DeVol

2006-06-30T23:59:59.000Z

326

Fracturing operations in a dry geothermal reservoir  

DOE Green Energy (OSTI)

Fracturing operations at the Fenton Hill, New Mexico, Hot Dry Rock (HDR) Geothermal Test Site initiated unique developments necessary to solve problems caused by an extremely harsh downhole environment. Two deep wells were drilled to approximately 15,000 ft (4.6 km); formation temperatures are in excess of 600/sup 0/F (315/sup 0/C). The wells were drilled during 1979 to 1981, inclined at 35 degrees, one above the other, and directionally drilled in an azimuthal direction orthogonal to the least principal in-situ crustal stress field. Hydraulic fracturing experiments to connect the two wells have used openhole packers, hydraulic jet notching of the borehole wall, cemented-in insolation liners and casing packers. Problems were encountered with hole drag, high fracture gradients, H/sub 2/S in vent back fluids, stress corrosion cracking of tubulars, and the complex nature of three-dimensional fracture growth that requires very large volumes of injected water. Two fractured zones have been formed by hydraulic fracturing and defined by close-in, borehole deployed, microseismic detectors. Initial operations were focused in the injection wellbore near total depth, where water injection treatments totalling 51,000 bbls (8100 m/sup 3/) were accomplished by pumping through a cemented-in 4-1/2 in. liner/PBR assembly. Retrievable casing packers were used to inject 26,000 bbls (4100 m/sup 3/) in the upper section of the open hole. Surface injection pressures (ISIP) varied from 4000 to 5900 psi (27 to 41 MPa) and the fracture gradient ranged from 0.7 to 0.96 psi/ft.

Rowley, J.C.; Pettitt, R.A.; Hendron, R.H.; Sinclair, A.R.; Nicholson, R.W.

1983-01-01T23:59:59.000Z

327

Brittle fracture phenomena: An hypothesis  

SciTech Connect

It is proposed that: volumetric dilation is a fundamental requirement for brittle fracture involving shear; such dilation commonly involves or is expressed as zonal overpressures; the overpressured zones radiate particle motions which are significant to or dominate seismic radiation from blasting; the overpressures are commonly significant to and may dominate the energetics of blastings. Outstanding problems and gaps in our knowledge regarding fragmentation are discussed. It is argued that there is a common missing factor, dilatancy. Supporting evidence is presented from soils and rock mechanics, blasting experimental data and blasting experience. Computer modeling of fragmentation is discussed and the necessity for the inclusion of dilatancy established. Implications are discussed and a test of the hypothesis proposed.

Britton, K.; Walton, O.R.

1987-05-01T23:59:59.000Z

328

Flow dynamics and solute transport in unsaturated rock fractures  

E-Print Network (OSTI)

and H. Brenner, Multiphase flow in porous media, Ann. Rev.to describe multiphase flow in porous media, involvingflow in porous media, can be generalized for multiphase flow

Su, G.W.

2011-01-01T23:59:59.000Z

329

Electrical resistivity imaging of conductive plume dilution in fractured rock  

E-Print Network (OSTI)

was injected into an injection well for 34 days to dilute a pre-existing potassium chloride (KCl) plume was conducted between the injection well and each of seven surrounding monitoring wells. Polar plots of the injection-well resistivity data in the direction of each monitoring well delineate specific locations where

Binley, Andrew

330

Eastern Regional Conference 2005 Fractured Rock Characterization Workshop  

E-Print Network (OSTI)

1992 1998 2002 GW #12;16 North Bedrock Upper Sand Marine Clay Lower Sand ca. 40m Sheet Pile.75 40.00 BBC4pressure[m] Open borehole MW Isolated Interval MW #12;52 LDSTs conducted on tight,tight are valuable for predicting well interconnectivities and to assess tight formations. · Sequences of interfering

New Hampshire, University of

331

FRACTURE DETECTION IN CRYSTALLINE ROCK USING ULTRASONIC SHEAR WAVES  

E-Print Network (OSTI)

of Energy, or the Swedish Nuclear Fuel Supply Company.through the Swedish Nuclear Fuel Supply Company (SKBF), andEnergy and/or the Swedish Nuclear Fuel Supply Company. Any

Waters, K.H.

2011-01-01T23:59:59.000Z

332

Capacitive discharge firing system for providing acoustic sources in the hot dry rock geothermal energy development project  

DOE Green Energy (OSTI)

The development of a capacitive discharge firing unit designed to initiate electrically exploded foil slapper detonators in a subsurface, high-pressure (5000 psi), high-temperature (> 200/sup 0/C) environment is described. The unit is used to conduct acoustic ranging experiments in deep boreholes (approx. = 10,000 ft) in the Los Alamos Scientific Laboratory Geothermal Hot Dry Rock experiment.

Patterson, W.W.; Deam, D.R.; MacDonald, H.J.; Rochester, R.H.

1979-07-01T23:59:59.000Z

333

High velocity impact fracture  

E-Print Network (OSTI)

An in-depth understanding of dynamic ductile fracture is one of the most important steps to improve the survivability of critical structures such as the lost Twin Towers. In the present thesis, the macroscopic fracture ...

Teng, Xiaoqing

2005-01-01T23:59:59.000Z

334

Characterization Of Fracture Patterns In The Geysers Geothermal Reservoir  

Open Energy Info (EERE)

Patterns In The Geysers Geothermal Reservoir Patterns In The Geysers Geothermal Reservoir By Shear-Wave Splitting Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: Characterization Of Fracture Patterns In The Geysers Geothermal Reservoir By Shear-Wave Splitting Details Activities (1) Areas (1) Regions (0) Abstract: The authors have analyzed the splitting of shear waves from microearthquakes recorded by a 16-station three-component seismic network at the Northwest Geysers geothermal field, Geysers, California, to determine the preferred orientation of subsurface fractures and cracks. Average polarization crack directions with standard deviation were computed for each station. Also, graphical fracture characterizations in the form of equal-area projections and rose diagrams were created to depict the

335

Characterizing Fractures in Geysers Geothermal Field by Micro-seismic Data,  

Open Energy Info (EERE)

Characterizing Fractures in Geysers Geothermal Field by Micro-seismic Data, Characterizing Fractures in Geysers Geothermal Field by Micro-seismic Data, Using Soft Computing, Fractals, and Shear Wave Anisotropy Geothermal Project Jump to: navigation, search Last modified on July 22, 2011. Project Title Characterizing Fractures in Geysers Geothermal Field by Micro-seismic Data, Using Soft Computing, Fractals, and Shear Wave Anisotropy Project Type / Topic 1 Recovery Act: Enhanced Geothermal Systems Component Research and Development/Analysis Project Type / Topic 2 Fracture Characterization Technologies Project Description The proposed program will focus on predicting characteristics of fractures and their orientation prior to drilling new wells. It will also focus on determining the location of the fractures, spacing and orientation during drilling, as well as characterizing open fractures after stimulation to help identify the location of fluid flow pathway within the EGS reservoir. These systems are created by passively injecting cold water, and stimulating the permeation of the injected water through existing fractures into hot wet and hot dry rocks by thermo-elastic cooling shrinkage. The stimulated, existing fractures thus enhance the permeability of the hot rock formations, hence enabling better circulation of water for the purpose of producing the geothermal resource. The main focus of the project will be on developing better understanding of the mechanisms for the stimulation of existing fractures, and to use the information for better exploitation of the high temperature geothermal resources located in the northwest portion of the Geysers field and similar fields.

336

Artificial geothermal reservoirs in hot volcanic rock  

SciTech Connect

S>Some recent results from the Los Alamos program in which hydraulic fracturing is used for the recovery of geothermal energy are discussed. The location is about 4 kilometers west and south of the ring fault of the enormous Jemez Caldera in the northcentral part of New Mexico. It is shown that geothermal energy may be extracted from hot rock that does not contain circulating hot water or steam and is relatively impermeable. A fluid is pumped at high pressure into an isolated section of a wellbore. If the well is cased the pipe in this pressurized region is perforated as it is in the petroleum industry, so that the pressure may be applied to the rock, cracking it. A second well is drilled a few hundred feet away from the first. Cold water is injected through the first pipe, circulates through the crack, and hot water returns to the surface through the second pipe. Results are described and circumstances are discussed under which artiflcial geothermal reservoirs might be created in the basaltic rock of Hawaii. (MCW)

Aamodt, R.L.

1974-02-08T23:59:59.000Z

337

Boiling radial flow in fractures of varying wall porosity  

DOE Green Energy (OSTI)

The focus of this report is the coupling of conductive heat transfer and boiling convective heat transfer, with boiling flow in a rock fracture. A series of experiments observed differences in boiling regimes and behavior, and attempted to quantify a boiling convection coefficient. The experimental study involved boiling radial flow in a simulated fracture, bounded by a variety of materials. Nonporous and impermeable aluminum, highly porous and permeable Berea sandstone, and minimally porous and permeable graywacke from The Geysers geothermal field. On nonporous surfaces, the heat flux was not strongly coupled to injection rate into the fracture. However, for porous surfaces, heat flux, and associated values of excess temperature and a boiling convection coefficient exhibited variation with injection rate. Nucleation was shown to occur not upon the visible surface of porous materials, but a distance below the surface, within the matrix. The depth of boiling was a function of injection rate, thermal power supplied to the fracture, and the porosity and permeability of the rock. Although matrix boiling beyond fracture wall may apply only to a finite radius around the point of injection, higher values of heat flux and a boiling convection coefficient may be realized with boiling in a porous, rather than nonporous surface bounded fracture.

Barnitt, Robb Allan

2000-06-01T23:59:59.000Z

338

Hot Dry Rock Geothermal Reservoir Testing- 1978 To 1980 | Open Energy  

Open Energy Info (EERE)

Dry Rock Geothermal Reservoir Testing- 1978 To 1980 Dry Rock Geothermal Reservoir Testing- 1978 To 1980 Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Hot Dry Rock Geothermal Reservoir Testing- 1978 To 1980 Details Activities (3) Areas (1) Regions (0) Abstract: The Phase I Hot Dry Rock Geothermal Energy reservoirs at the Fenton Hill field site grew continuously during Run Segments 2 through 5 (January 1978 to December 1980). Reservoir growth was caused not only by pressurization and hydraulic fracturing, but also by heat-extraction and thermal-contraction effects. Reservoir heat-transfer area grew from 8000 to 50,000 m2 and reservoir fracture volume grew from 11 to 266 m3. Despite this reservoir growth, the water loss rate increased only 30%, under similar pressure environments. For comparable temperature and pressure

339

THE INFLUENCE OF FOLD AND FRACTURE DEVELOPMENT ON RESERVOIR BEHAVIOR OF THE LISBURNE GROUP OF NORTHERN ALASKA  

Science Conference Proceedings (OSTI)

The Carboniferous Lisburne Group is a major carbonate reservoir unit in northern Alaska. The Lisburne is detachment folded where it is exposed throughout the northeastern Brooks Range, but is relatively undeformed in areas of current production in the subsurface of the North Slope. The objectives of this study are to develop a better understanding of four major aspects of the Lisburne: (1) The geometry and kinematics of detachment folds and their truncation by thrust faults. (2) The influence of folding on fracture patterns. (3) The influence of deformation on fluid flow. (4) Lithostratigraphy and its influence on folding, faulting, fracturing, and reservoir characteristics. The Lisburne in the main axis of the Brooks Range is characteristically deformed into imbricate thrust sheets with asymmetrical hanging wall anticlines and footwall synclines. In contrast, the Lisburne in the northeastern Brooks Range is characterized by symmetrical detachment folds. The focus of our 2000 field studies was at the boundary between these structural styles in the vicinity of Porcupine Lake, in the Arctic National Wildlife Refuge. The northern edge of thrust-truncated folds in Lisburne is marked by a local range front that likely represents an eastward continuation of the central Brooks Range front. This is bounded to the north by a gently dipping panel of Lisburne with local asymmetrical folds. The leading edge of the flat panel is thrust over Permian to Cretaceous rocks in a synclinal depression. These younger rocks overlie symmetrically detachment-folded Lisburne, as is extensively exposed to the north. Six partial sections were measured in the Lisburne of the flat panel and local range front. The Lisburne here is about 700 m thick and is interpreted to consist primarily of the Wachsmuth and Alapah Limestones, with only a thin veneer of Wahoo Limestone. The Wachsmuth (200 m) is gradational between the underlying Missippian Kayak Shale and the overlying Mississippian Alapah, and increases in resistance upward. The Alapah consists of a lower resistant member (100 m) of alternating limestone and chert, a middle recessive member (100 m), and an upper resistant member (260 m) that is similar to Wahoo in the northeastern Brooks Range. The Wahoo is recessive and is thin (30 m) due either to non-deposition or erosion beneath the sub-Permian unconformity. The Lisburne of the area records two major episodes of transgression and shallowing-upward on a carbonate ramp. Thicknesses and facies vary along depositional strike. Asymmetrical folds, mostly truncated by thrust faults, were studied in and south of the local range front. Fold geometry was documented by surveys of four thrust-truncated folds and two folds not visibly cut by thrusts. A portion of the local range front was mapped to document changes in fold geometry along strike in three dimensions. The folds typically display a long, non-folded gently to moderately dipping backlimbs and steep to overturned forelimbs, commonly including parasitic anticline-syncline pairs. Thrusts commonly cut through the anticlinal forelimb or the forward synclinal hinge. These folds probably originated as detachment folds based on their mechanical stratigraphy and the transition to detachment folds to the north. Their geometry indicates that they were asymmetrical prior to thrust truncation. This asymmetry may have favored accommodation of increasing shortening by thrust breakthrough rather than continued folding. Fracture patterns were documented in the gently dipping panel of Lisburne and the asymmetrical folds within it. Four sets of steeply dipping extension fractures were identified, with strikes to the (1) N, (2) E, (3) N to NW, and (4) NE. The relative timing of these fracture sets is complex and unclear. En echelon sets of fractures are common, and display normal or strike-slip sense. Mesoscopic and penetrative structures are locally well developed, and indicate bed-parallel shear within the flat panel and strain within folds. Three sets of normal faults are well developed in the area, and are unusual

Wesley K. Wallace; Catherine L. Hanks; Jerry Jensen; Michael T. Whalen

2002-01-01T23:59:59.000Z

340

Analysis of the structural parameters that influence gas production from the Devonian shale. Annual progress report, 1979-1980. Volume II. Data repository and reports published during fiscal year 1979-1980: regional structure, surface structure, surface fractures, hydrology  

SciTech Connect

This volume comprises appendices giving regional structure data, surface structure data, surface fracture data, and hydrology data. The fracture data covers oriented Devonian shale cores from West Virginia, Ohio, Virginia, Pennsylvania, and Kentucky. The subsurface structure of the Eastern Kentucky gas field is also covered. (DLC)

Negus-De Wys, J.; Dixon, J. M.; Evans, M. A.; Lee, K. D.; Ruotsala, J. E.; Wilson, T. H.; Williams, R. T.

1980-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Petrography and geochemistry of precambrian rocks from GT-2 and EE-1  

DOE Green Energy (OSTI)

During the drilling of GT-2 and EE-1, 27 cores totaling about 35 m were collected from the Precambrian section. Samples of each different lithology in each core were taken for petrographic and whole-rock major- and trace-element analyses. Whole-rock analyses are now completed on 37 samples. From these data four major Precambrian units were identified at the Fenton Hill site. Geophysical logs and cuttings were used to extrapolate between cores. The most abundant rock type is an extremely variable gneissic unit comprising about 75% of the rock penetrated. This rock is strongly foliated and may range compositionally from syenogranitic to tonalitic over a few centimeters. The bulk of the unit falls within the monzogranite field. Interlayered with the gneiss is a ferrohastingsite-biotite schist which compositionally resembles a basaltic andesite. A fault contact between the schist and gneiss was observed in one core. Intrusive into this metamorphic complex are two igneous rocks. A leucocratic monzogranite occurs as at least two 15-m-thick dikes, and a biotite-granodiorite body was intercepted by 338 m of drill hole. Both rocks are unfoliated and equigranular. The biotite granodiorite is very homogeneous and is characterized by high modal contents of biotite and sphene and by high K/sub 2/O, TiO/sub 2/, and P/sub 2/O/sub 5/ contents. Although all of the cores examined show fractures, most of these are tightly sealed or healed. Calcite is the most abundant fracture filling mineral, but epidote, quartz, chlorite, clays or sulfides have also been observed. The degree of alteration of the essential minerals normally increases as these fractures are approached. The homogeneity of the biotite granodiorite at the bottom of GT-2 and the high degree of fracture filling ensure an ideal setting for the Hot Dry Rock Experiment.

Laughlin, A.W.; Eddy, A.

1977-08-01T23:59:59.000Z

342

Developing hot dry rock reservoirs with inflatable open hole packers  

DOE Green Energy (OSTI)

An open hole packer system was designed for high pressure injection operations in high temperature wells at the Fenton Hill, Hot Dry Rock (HDR) Geothermal Site. The packer runs were required to verify that the HDR reservoir fractures had been penetrated during the drilling of well EE-3A. They were also used to stimulate fractures connecting EE-3A to the reservoir and to conduct two massive hydraulic fracture treatments at the bottom of EE-3A. An attempt to use a modified packer design as a temporary well completion system was not successful but with modification the system may prove to be an important HDR completion technique. The eleven packer runs have demonstrated that formation testing, stimulation and HDR reservoir development can now be conducted with an open hole inflatable packer operating over large temperature ranges and high differential pressures.

Dreesen, D.S.; Miller, J.R.; Nicholson, R.W.

1987-01-01T23:59:59.000Z

343

Parallel heater system for subsurface formations  

DOE Patents (OSTI)

A heating system for a subsurface formation is disclosed. The system includes a plurality of substantially horizontally oriented or inclined heater sections located in a hydrocarbon containing layer in the formation. At least a portion of two of the heater sections are substantially parallel to each other. The ends of at least two of the heater sections in the layer are electrically coupled to a substantially horizontal, or inclined, electrical conductor oriented substantially perpendicular to the ends of the at least two heater sections.

Harris, Christopher Kelvin (Houston, TX); Karanikas, John Michael (Houston, TX); Nguyen, Scott Vinh (Houston, TX)

2011-10-25T23:59:59.000Z

344

Low temperature monitoring system for subsurface barriers  

DOE Patents (OSTI)

A system for monitoring temperature of a subsurface low temperature zone is described. The system includes a plurality of freeze wells configured to form the low temperature zone, one or more lasers, and a fiber optic cable coupled to at least one laser. A portion of the fiber optic cable is positioned in at least one freeze well. At least one laser is configured to transmit light pulses into a first end of the fiber optic cable. An analyzer is coupled to the fiber optic cable. The analyzer is configured to receive return signals from the light pulses.

Vinegar, Harold J. (Bellaire, TX); McKinzie, II. Billy John (Houston, TX)

2009-08-18T23:59:59.000Z

345

Alternate operating strategies for Hot Dry Rock geothermal reservoirs  

DOE Green Energy (OSTI)

Flow testing and heat extraction experiments in prototype Hot Dry Rock (HDR) geothermal reservoirs have uncovered several challenges which must be addressed before commercialization of the technology is possible. Foremost among these is the creation of a reservoir which simultaneously possesses high permeability pathways and a large volume of fractured rock. The current concept of heat extraction -- a steady state circulation system with fluid pumping from the injection well to a single, low pressure production well -- may limit our ability to create heat extraction systems which meet these goals. A single injection well feeding two production wells producing fluid at moderate pressures is shown to be a potentially superior way to extract heat. Cyclic production is also demonstrated to have potential as a method for sweeping fluid through a larger volume of rock, thereby inhibiting flow channeling and increasing reservoir lifetime. 10 refs., 4 figs., 2 tabs.

Robinson, B.A.

1991-01-01T23:59:59.000Z

346

Comparison of two hot dry rock geothermal reservoirs  

DOE Green Energy (OSTI)

Two hot dry rock (HDR) geothermal energy reservoirs were created by hydraulic fracturing of granite at 2.7 to 3.0 km (9000 to 10,000 ft) at the Fenton Hill site, near the Valles Caldera in northern New Mexico. Both reservoirs are research reservoirs, in the sense that both are fairly small, generally yielding 5 MWt or less, and are intended to serve as the basic building blocks of commercial-sized reservoirs, consisting of 10 to 15 similar fractures that would yield approximately 35 MWt over a 10 to 20 yr period. Both research reservoirs were created in the same well-pair, with energy extraction well number 1 (EE-1) serving as the injection well, and geothermal test well number 2 (GT-2) serving as the extraction, or production, well. The first reservoir was created in the low permeability host rock by fracturing EE-1 at a depth of 2.75 km (9020 ft) where the indigenous temperature was 185/sup 0/C (364/sup 0/F). A second, larger reservoir was formed by extending a small, existing fracture at 2.93 km (9620 ft) in the injection well about 100 m deeper and 10/sup 0/C hotter than the first reservoir. The resulting large fracture propagated upward to about 2.6 km (8600 ft) and appeared to Rave an inlet-to-outlet spacing of 300m (1000 ft), more then three times that of the first fracture. Comparisons are made with the first reservoir. Evaluation of the new reservoir was accomplished in two steps: (1) with a 23-day heat extraction experiment that began October 23, 1979, and (2) a second, longer-term heat extraction experiment still in progress, which as of November 25, 1980 has been in effect for 260 days. The results of this current experiment are compared with earlier experiments.

Murphy, H.D.; Tester, J.W.; Potter, R.M.

1980-01-01T23:59:59.000Z

347

Angle of crack propagation for a vertical hydraulic fracture  

DOE Green Energy (OSTI)

Using the strain-energy-density-factor (S) theory, the positive fracture angle +theta/sub o/ (the initial fracture angle of crack propagation) of a near-vertical crack is predicted by using the opening- and sliding-mode stress-intensity factors in the presence of the overburden pressure, the least in situ horizontal principal stress, and the borehole fluid pressure. The crack spreads in the positive theta/sub o/ direction (counter-clockwise) in the plane for which S is a minimum, S/sub min/. It was verified that S/sub min/ is greater than or equal to S/sub c/. The quantity S/sub c/ is defined as the critical value of S, and remains essentially constant. Of interest is the numerical example for calculating fracture angle and the critical uniform borehole fluid pressure required to initiate fracture at such an angle for the present LASL Dry Hot Rock Geothermal Energy Program. (auth)

Sarda, J.P.; Hsu, Y.C.

1975-12-01T23:59:59.000Z

348

Fracture characteristics and their relationships to producing zones in deep  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Fracture characteristics and their relationships to producing zones in deep wells, Raft River geothermal area Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Book: Fracture characteristics and their relationships to producing zones in deep wells, Raft River geothermal area Details Activities (1) Areas (1) Regions (0) Abstract: Fracture characteristics in the sedimentary and metamorphic rocks in the Raft River KGRA of Idaho are analyzed using geological, hydrological and borehole geophysical data from five deep geothermal production wells. Particular emphasis is placed on fracture identification using borehole

349

Chombo-Crunch: Advanced Simulation of Subsurface Flow and Reactive...  

NLE Websites -- All DOE Office Websites (Extended Search)

Chombo-Crunch: Advanced Simulation of Subsurface Flow and Reactive Transport Processes Associated with Carbon Sequestration PI Name: David Trebotich Institution: Lawrence Berkeley...

350

Why sequence archaea in a terrestrial subsurface aquifer?  

NLE Websites -- All DOE Office Websites (Extended Search)

genome sequencing. Principal Investigators: Wen-Tso Liu, University of Illinois Program: CSP 2011 Home > Sequencing > Why sequence archaea in a terrestrial subsurface aquifer...

351

EMSL: Science: Geochemistry/Biogeochemistry and Subsurface Science  

NLE Websites -- All DOE Office Websites (Extended Search)

GeochemistryBiogeochemistry and Subsurface Science pyramid-like surface structure of the mineral, hematite Pyramid-like surface structure of the mineral, hematite Research in this...

352

Historical Ocean Subsurface Temperature Analysis with Error Estimates  

Science Conference Proceedings (OSTI)

An objective analysis of monthly ocean subsurface temperatures from 1950 to 1998 is carried out. The analysis scheme and the results with estimated analysis errors are presented.

Masayoshi Ishii; Masahide Kimoto; Misako Kachi

2003-01-01T23:59:59.000Z

353

Growth of geologic fractures into large-strain populations: review of nomenclature, subcritical crack growth, and some implications  

E-Print Network (OSTI)

. An array of initially mixed-mode (I±II) cracks will evolve under remote tensile least principal stress±network evolution. An increase in the stress corrosion index promotes joint clustering and signi®cant changes crack growth, and some implications for rock engineering R.A. Schultz* Geomechanics-Rock Fracture Group

354

Self-potential observations during hydraulic fracturing  

E-Print Network (OSTI)

potential measurements during hydraulic fracturing of BunterMonitoring during hydraulic fracturing using the TG-2 well,fracture processes in hydraulic fracturing, Quarterly Report

Moore, Jeffrey R.; Glaser, Steven D.

2008-01-01T23:59:59.000Z

355

Location of hydraulic fractures using microseismic techniques  

DOE Green Energy (OSTI)

Microearthquakes with magnitudes ranging between -6 and -2 have been observed in three successive massive injections of water at the Hot Dry Rock Geothermal Energy demonstration site at Fenton Hill, New Mexico. The injection was part of a program to increase the heat transfer area of hydraulic fractures and to decrease the flow-through impedance between wells. The microearthquakes were used in mapping the location of the extended hydraulic fractures. A downhole triaxial system positioned approximately 200 m vertically above the injection point in a shut-in production well was used for detection. The microearthquakes occurred in a north-northwest striking zone 400 m in length passing through the injection point. During a third substantially larger injection, microearthquakes occurred in a dispersed volume at distances as great as 800 m from the zone active in the first two injections.

Albright, J.A.; Pearson, C.F.

1980-01-01T23:59:59.000Z

356

Instruments for subsurface monitoring of geothermal subsidence  

DOE Green Energy (OSTI)

The requirements for a subsurface geothermal subsidence instrument were reviewed. Available instruments for monitoring subsurface displacements, both vertical and horizontal, were studied and the most capable instruments identified. Techniques and materials for improving existing or developing new instruments were evaluated. Elements of sensor and signal technology with potential for high temperature monitoring of subsidence were identified. Drawing from these studies, methods to adapt production wells for monitoring were proposed and several new instrumentation systems were conceptually designed. Finally, four instrumentation systems were selected for future development. These systems are: triple sensor induction sensor probe (with casing collar markers); triple sensor gamma ray detector probe (with radioactive markers); triple sensor reed switch probe (with magnet markers); and triple sensor oscillator-type magnet detector probe (with magnet markers). All are designed for use in well casing incorporating slip couplings or bellows sections, although the gamma ray detector probe may also be used in unlined holes. These systems all measure vertical moement. Instruments to measure horizontal displacement due to geothermal subsidence were studied and the required instrument performance was judged to be beyond the state-of-the-art. Thus, no conceptual designs for instruments to monitor horizontal movement are included.

O'Rourke, J.E.; Ranson, B.B.

1979-07-01T23:59:59.000Z

357

The Landscape of Klamath Basin Rock Art  

E-Print Network (OSTI)

the Lines: Ethnographic Sources and Rock Art Interpretationwhen applying these sources toward rock art interpretation.information source for developing rock art interpretations.

David, Robert James

2012-01-01T23:59:59.000Z

358

A new method for determining dominant fluid flow paths during hydraulic fracturing  

DOE Green Energy (OSTI)

Although hydraulic fracturing is a method that has been applied for many years to increase fracture permeability of reservoirs, there is no direct way other than drilling additional boreholes to determine where the injected fluid has gone and thus what direction fractures have propagated. Information about fluid flow paths is important for designing subsequent fracturing operations for nearby wells or for choosing a trajectory for a second well to drill through the fracture system, and thus create a hot dry rock geothermal energy reservoir. A method has been developed for determining the orientations and locations of fractures along which fluid flows during hydraulic fracturing. The method is based on accurate determination of the locations of microseismic events, or microearthquakes, that accompany the hydraulic injection. The method has been applied to data collected during a massive hydraulic fracturing experiment carried out as part of the hot dry rock project. Planes with five different orientations were found in the data. The planes determined using the method intersect the injection borehole and a second, nearby borehole, in regions where other data indicate that fractures are present.

Fehler, M.

1987-01-01T23:59:59.000Z

359

Experimental Determination of Tracer Dispersivity in Fractures  

DOE Green Energy (OSTI)

Reinjection of waste hot water is commonly practiced in most geothermal fields, primarily as a means of disposal. Surface discharge of these waste waters is usually unacceptable due to the resulting thermal and chemical pollution. Although reinjection can help to main reservoir pressure and fluid volume, in some cases a decrease in reservoir productivity has been observed. This is caused by rapid flow of the reinjected water through fractures connecting the injector and producers. As a result, the water is not sufficiently heated by the reservoir rock, and a reduction in enthalpy of the produced fluids is seen. Tracer tests have proven to be valuable to reservoir engineers for the design of a successful reinjection program. By injecting a slug of tracer and studying the discharge of surrounding producing wells, an understanding of the fracture network within a reservoir can be provided. In order to quantify the results of a tracer test, a model that accurately describes the mechanisms of tracer transport is necessary. One such mechanism, dispersion, is like a smearing out of a tracer concentration due to the velocity gradients over the cross section of flow. If a dispersion coefficient can be determined from tracer test data, the fracture width can be estimated. The purpose of this project was to design and construct an apparatus to study the dispersion of a chemical tracer in flow through a fracture.

Gilardi, J.; Horns, R.N.

1985-01-22T23:59:59.000Z

360

Rock Harbor UNITED STATES  

E-Print Network (OSTI)

Passage Conglomerate Bay Five Finger Bay Lane Cove Stockly Bay Lake Ojibway Siskiwit River Creek Little River Washington Moskey M cCargoe Cove Robinson Bay Amygdaloid Channel Pickerel Cove Chippewa Harbor Crystal Cove Belle Isle Canoe Rocks Caribou Island Saginaw Point Tookers Island The Palisades Raspberry

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Seismic reconnaissance of the Los Alamos Scientific Laboratory's Dry Hot Rock Geothermal Project area  

DOE Green Energy (OSTI)

Active seismic methods using high-explosive sources and nondestructive energy sources were used to determine seismic velocities, signal detectability, and subsurface geologic structure in the vicinity of the Los Alamos Scientific Laboratory's (LASL) Dry Hot Rock Geothermal Project area. Positions of several faults have been determined. A synthetic seismogram has been created that shows good agreement with recorded reflection records taken near exploratory borehole GT-2.

Kintzinger, P.R.; West, F.G.

1976-07-01T23:59:59.000Z

362

Numerical Investigation of Fractured Reservoir Response to Injection/Extraction Using a Fully Coupled Displacement Discontinuity Method  

E-Print Network (OSTI)

In geothermal reservoirs and unconventional gas reservoirs with very low matrix permeability, fractures are the main routes of fluid flow and heat transport, so the fracture permeability change is important. In fact, reservoir development under this circumstance relies on generation and stimulation of a fracture network. This thesis presents numerical simulation of the response of a fractured rock to injection and extraction considering the role of poro-thermoelasticity and joint deformation. Fluid flow and heat transport in the fracture are treated using a finite difference method while the fracture and rock matrix deformation are determined using the displacement discontinuity method (DDM). The fractures response to fluid injection and extraction is affected both by the induced stresses as well as by the initial far-field stress. The latter is accounted for using the non-equilibrium condition, i.e., relaxing the assumption that the rock joints are in equilibrium with the in-situ stress state. The fully coupled DDM simulation has been used to carry out several case studies to model the fracture response under different injection/extractions, in-situ stresses, joint geometries and properties, for both equilibrium and non-equilibrium conditions. The following observations are made: i) Fluid injection increases the pressure causing the joint to open. For non-isothermal injection, cooling increases the fracture aperture drastically by inducing tensile stresses. Higher fracture aperture means higher conductivity. ii) In a single fracture under constant anisotropic in-situ stress (non-equilibrium condition), permanent shear slip is encountered on all fracture segments when the shear strength is overcome by shear stress in response to fluid injection. With cooling operation, the fracture segments in the vicinity of the injection point are opened due to cooling-induced tensile stress and injection pressure, and all the fracture segments experience slip. iii) Fluid pressure in fractures increases in response to compression. The fluid compressibility and joint stiffness play a role. iv) When there are injection and extraction in fractured reservoirs, the cooler fluid flows through the fracture channels from the injection point to extraction well extracting heat from the warmer reservoir matrix. As the matrix cools, the resulting thermal stress increases the fracture apertures and thus increases the fracture conductivity. v) Injection decreases the amount of effective stress due to pressure increase in fracture and matrix near a well. In contrast, extraction increases the amount of effective stress due to pressure drop in fracture and matrix.

Lee, Byungtark

2011-08-01T23:59:59.000Z

363

A combined heat transfer and quartz dissolution/deposition model for a hot dry rock geothermal reservoir  

DOE Green Energy (OSTI)

A kinetic model of silica transport has been coupled to a heat transfer model for a Hot Dry Rock (HDR) geothermal reservoir to examine the effect of silica rock-water interactions on fracture aperture and permeability. The model accounts for both the dissolution and deposition of silica. Zones of local dissolution and deposition were predicted, but their effect on aperture and permeability were fairly small for all cases studied. Initial rock temperature, reservoir size, and the ratio of rock surface area to fluid volume have the largest effect on the magnitude of silica mass transferred between the liquid and solid phases. 13 refs., 6 figs.

Robinson, B.A.; Pendergrass, J.

1989-01-01T23:59:59.000Z

364

Summary - Hot Dry Rock R&D Strategies and Applications  

DOE Green Energy (OSTI)

In geothermal energy technology, the hydrothermal systems rely on volcanic hot rocks being fortuitously co-located with an adequate supply of natural ground water, usually at some considerable depth within the earth. This represents essentially two accidents in the same place, and the occurrence is relatively rare. Yellowstone Park and the desert valley of southern California are the most noteworthy US. examples. Since the heat is the energy needed, if we could just get the water down to it and back. Well, that's what is being done with the hot dry rock program. A well is drilled down to where there is adequate heat in the rocks. The well is then pressurized until the rock fractures creating what amounts to a reservoir full of hot, shattered rock. Finally, a well is drilled into the reservoir and water is pumped in one well, heated by the rock, and taken out through the other well at useful temperatures and pressures. We are getting ready to run significant long-term flow tests at the Fenton Hill Hot Dry Rock site west of Los Alamos, New Mexico. We expect the operational information to provide the data to forecast the energy life of the wells as a production facility. This kind of resource is much more common than regular geothermal resources. Robert H. Hendron described the Long Term Flow Test and reservoir studies for which the project is preparing. A shortfall of available funding has slowed preparations, delaying the start of that test. The test is planning to gather data for more definitive reservoir modeling with energy availability or reservoir lifetime of primary interest. Other interests include geochemistry and tracer studies, microseismic response, water requirements and flow impedance which relates directly to the pumping power required. Progress has been made in modeling studies, chemically reactive tracer techniques, and in improvements in acoustic or microseismic event analysis. Donald W. Brown discussed reservoir modeling as it relates to production management of the HDR well. For wells which are fracture dominated rather than matrix-permeability controlled, a knowledge of the pressure-dependent permeability of the interconnected system of natural joints (or pre-existing fractures is critical to long-term power production from the wells) through optimized pressure management. It was mentioned that a knowledge of the pressure-dependent joint permeability could aid in designing more appropriate secondary recovery strategies in petroleum reservoirs, or reinjection I procedures of geothermal reservoirs. Dr. Bruce A. Robinson discussed the development of fluid flow and transport models for simulation of HDR geothermal reservoirs. These models are also expected to provide accurate predictions of long-term behavior and help in the development of strategies for reservoir improvement and operation. Two approaches were discussed. The discrete fracture approach is based on a random fracture network subject to prescribed statistical properties of the fracture set. It is used to simulate steady state fluid flow and solute transport. The other approach used the continuum approximation. This type of model is appropriate when the reservoir consists of many interconnected fractures, as is the case at Fenton Hill.

Tennyson, George P..

1989-03-21T23:59:59.000Z

365

Measuring and Modeling Flow in Welded Fractured Tuffs  

SciTech Connect

We have carried out a series of in situ liquid-release experiments in conjunction with a numerical modeling study to examine the effect of the rock matrix on liquid flow and transport occurring primarily through the fracture network. Field experiments were conducted in the highly fractured Topopah Spring welded tuff at a site accessed from the Exploratory Studies Facility (ESFS), an underground laboratory in the unsaturated zone at Yucca Mountain, Nevada. During the experiment, wetting-front movement, flow-field evolution, and drainage of fracture flow paths were evaluated. Modeling was used to aid in experimental design, predict experimental results, and study the physical processes accompanying liquid flow through unsaturated fractured welded tuff. Field experiments and modeling suggest that it may not be sufficient to conceptualize the fractured tuff as consisting of a single network of high-permeability fractures embedded in a low-permeability matrix. The need to include a secondary fracture network is demonstrated by comparison to the liquid flow observed in the field.

R. Salve; C. Doughty; J.S. Wang

2001-10-03T23:59:59.000Z

366

Fracturing results in diatomaceous earth formations, South Belridge Field, California  

SciTech Connect

Fracturing significantly increases light oil production rates at South Belridge making this an economically successful technique for exploitation of the Reef Ridge reservoir. No fracturing mechanics problems were encountered in any of the treatments. The loosely consolidated formations behaved mechanically much like brittle, elastic rocks. Net oil and gross production is typified by initial high rates and an early rapid decline. The major cause of this early rapid decline is the transient flow effect. This behavior is typical of low permeability oil and gas production. Fractures are vertical, as shown by gamma ray and temperature logs run following several treatments. The fractures grow slightly out of the perforated intervals (10 to 15 feet). Loss of fracture conductivity due to fines migration, scale deposition, and/or fracture healing (imbedment) is not a serious problem. Oil viscosity can vary as much as ten-fold. Some wells produce significant amounts of gas--100 to 200 MCFPD initially. The formation is primarily diatomaceous earth which is very fine particle size siliceous material composed of whole or fragmented diatom tests (skeletons). There is no evidence that clay swelling or dispersion is a problem. Field and laboratory data support this conclusion. Aqueous fracturing fluids were successfully used which confirmed laboratory tests on cores.

Strubhar, M.K.; Medin, W.L.

1982-09-01T23:59:59.000Z

367

Measurement of Solute Diffusion Behavior in Fractured Waste Glass Media  

SciTech Connect

Determination of aqueous phase diffusion coefficients of solutes through fractured media is essential for understanding and modeling contaminants transport at many hazardous waste disposal sites. No methods for earlier measurements are available for the characterization of diffusion in fractured glass blocks. We report here the use of time-lag diffusion experimental method to assess the diffusion behavior of three different solutes (Cs, Sr and Pentafluoro Benzoic Acid or PFBA) in fractured, immobilized low activity waste (ILAW) glass forms. A fractured media time-lag diffusion experimental apparatus that allows the measurement of diffusion coefficients has been designed and built for this purpose. Use of time-lag diffusion method, a considerably easier experimental method than the other available methods, was not previously demonstrated for measuring diffusion in any fractured media. Hydraulic conductivity, porosity and diffusion coefficients of a solute were experimentally measured in fractured glass blocks using this method for the first time. Results agree with the range of properties reported for similar rock media earlier, indicating that the time-lag experimental method can effectively characterize the diffusion coefficients of fractured ILAW glass media.

Saripalli, Kanaka P.; Lindberg, Michael J.; Meyer, Philip D.

2008-10-01T23:59:59.000Z

368

ASSESSMENT OF THE SUBSURFACE FATE OF MONOETHANOLAMINE  

SciTech Connect

Burial of amine reclaimer unit sludges and system filters has resulted in contamination of soil at the CanOxy Okotoks decommissioned sour gas-processing plant with amines, amine byproducts, and salts. A three-phase research program was devised to investigate the natural attenuation process that controls the subsurface transport and fate of these contaminants and to apply the results toward the development of a strategy for the remediation of this type of contamination in soils. Phase I experimental activities examined interactions between monoethanolamine (MEA) and sediment, the biodegradability of MEA in soils at various concentrations and temperatures, and the biodegradability of MEA sludge contamination in a soil slurry bioreactor. The transport and fate of MEA in the subsurface was found to be highly dependant on the nature of the release, particularly MEA concentration and conditions of the subsurface environment, i.e., pH, temperature, and oxygen availability. Pure compound biodegradation experiments in soil demonstrated rapid biodegradation of MEA under aerobic conditions and moderate temperatures (>6 C). Phase II landfarming activities confirmed that these contaminants are readily biodegradable in soil under ideal laboratory conditions, yet considerable toxicity was observed in the remaining material. Examination of water extracts from the treated soil suggested that the toxicity is water-soluble. Phase II activities led to the conclusion that landfarming is not the most desirable bioremediation technique; however, an engineered biopile with a leachate collection system could remove the remaining toxic fraction from the soil. Phase III was initiated to conduct field-based experimental activities to examine the optimized remediation technology. A pilot-scale engineered biopile was constructed at a decommissioned gas-sweetening facility in Okotoks, Alberta, Canada. On the basis of a review of the analytical and performance data generated from soil and leachate samples, the biopile operation has successfully removed all identified amines and removed significant amounts of organic nitrogen and organic carbon. Salts initially present in the soil and salts generated during the biodegradation of contaminants remain to be flushed from the soil. Laboratory data show that these salts are readily removable with a simple soil leach.

James A. Sorensen; John R. Gallagher; Lori G. Kays

2000-05-01T23:59:59.000Z

369

Subsurface geology of the Raft River geothermal area, Idaho | Open Energy  

Open Energy Info (EERE)

geology of the Raft River geothermal area, Idaho geology of the Raft River geothermal area, Idaho Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: Subsurface geology of the Raft River geothermal area, Idaho Details Activities (1) Areas (1) Regions (0) Abstract: The Raft River Valley occupies an upper Cenozoic structural basin filled with nearly 1600 m of fluvial silt, sand, and gravel. Rapid facies and thickness changes, steep initial dips (30 0C), and alteration make correlation of basin-fill depositional units very difficult. Hydrothermal alteration products in the form of clays and zeolites, and deposition of secondary calcite and silica increase with depth. The abundance of near-vertical open fractures also increases with depth, allowing greater movement of hydrothermal fluids near the base of the Cenozoic basin fill.

370

Definition: Rock Density | Open Energy Information  

Open Energy Info (EERE)

in crustal rocks. Rock density is a physical characteristic that is governed by the chemical composition (in situ minerals) and pore spaces of a specific rock or rock type.1...

371

A study of steam injection in fractured media  

SciTech Connect

Steam injection is the most widely used thermal recovery technique for unfractured reservoirs containing heavy oil. There have been numerous studies on theoretical and experimental aspects of steam injection for such systems. Fractured reservoirs contain a large fraction of the world supply of oil, and field tests indicate that steam injection is feasible for such reservoirs. Unfortunately there has been little laboratory work done on steam injection in such systems. The experimental system in this work was designed to understand the mechanisms involved in the transfer of fluids and heat between matrix rocks and fractures under steam injection.

Dindoruk, M.D.S.; Aziz, K.; Brigham, W.; Castanier, L.

1996-02-01T23:59:59.000Z

372

Analysis Of Macroscopic Fractures In Granite In The Hdr Geothermal Well  

Open Energy Info (EERE)

Macroscopic Fractures In Granite In The Hdr Geothermal Well Macroscopic Fractures In Granite In The Hdr Geothermal Well Eps-1, Soultz-Sous-Forets, France Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Analysis Of Macroscopic Fractures In Granite In The Hdr Geothermal Well Eps-1, Soultz-Sous-Forets, France Details Activities (0) Areas (0) Regions (0) Abstract: An exhaustive analysis of 3000 macroscopic fractures encountered in the geothermal Hot Dry Rock borehole, EPS-1, located inside the Rhine graben (Soultz-sous-Forets, France), was done on a continuous core section over a depth interval from 1420 to 2230 m: 97% of the macroscopic structures were successfully reorientated with a good degree of confidence by comparison between core and acoustic borehole imagery. Detailed structural analysis of the fracture population indicates that fractures are

373

Technologies Provide High-Resolution Subsurface Imaging of Vadose Zone  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Technologies Provide High-Resolution Subsurface Imaging of Vadose Technologies Provide High-Resolution Subsurface Imaging of Vadose Zone Contamination at Hanford Site Technologies Provide High-Resolution Subsurface Imaging of Vadose Zone Contamination at Hanford Site May 17, 2012 - 12:00pm Addthis Shown here are high-resolution, three-dimensional ERT images of contaminant distribution Shown here are high-resolution, three-dimensional ERT images of contaminant distribution RICHLAND, Wash. - Cold War waste disposal practices resulted in both planned and unplanned releases of large amounts of radionuclide and heavy metal contamination into the subsurface throughout the DOE complex. Characterizing the distribution of the resulting environmental contamination remains one of the single most significant challenges limiting subsurface remediation and closure, particularly for the

374

Armored Enzyme Nanoparticles for Remediation of Subsurface  

Science Conference Proceedings (OSTI)

The remediation of subsurface contaminants is a critical problem for the Department of Energy, other government agencies, and our nation. Severe contamination of soil and groundwater exists at several DOE sites due to various methods of intentional and unintentional release. Given the difficulties involved in conventional removal or separation processes, it is vital to develop methods to transform contaminants and contaminated earth/water to reduce risks to human health and the environment. Transformation of the contaminants themselves may involve conversion to other immobile species that do not migrate into well water or surface waters, as is proposed for metals and radionuclides; or degradation to harmless molecules, as is desired for organic contaminants. Transformation of contaminated earth (as opposed to the contaminants themselves) may entail reductions in volume or release of bound contaminants for remediation.

Grate, Jay W.

2005-09-01T23:59:59.000Z

375

REPOSITORY SUBSURFACE LAYOUT OPTIONS AND ESF INTERFACE  

SciTech Connect

This report summarizes work completed by the repository subsurface design group during the 1993 fiscal year (FY93), and represents a portion of the ongoing, repository Advanced Conceptual Design (ACD) effort. The ACD work is being performed in accordance with guidance and controls established for the United States Department of Energy's (DOE) Yucca Mountain Project (YMP). This document draws information from other ACD reports prepared and submitted during the year, and from other program studies, including the Exploratory Studies Facility (ESF) Title II design. Site specific data gathered by the Surface Based Testing (SBT) program has been included to the extent that it became available early enough for use in the designs presented herein.

Dana J. Rogers

1993-12-20T23:59:59.000Z

376

Repository Subsurface Preliminary Fire Hazard Analysis  

Science Conference Proceedings (OSTI)

This fire hazard analysis identifies preliminary design and operations features, fire, and explosion hazards, and provides a reasonable basis to establish the design requirements of fire protection systems during development and emplacement phases of the subsurface repository. This document follows the Technical Work Plan (TWP) (CRWMS M&O 2001c) which was prepared in accordance with AP-2.21Q, ''Quality Determinations and Planning for Scientific, Engineering, and Regulatory Compliance Activities''; Attachment 4 of AP-ESH-008, ''Hazards Analysis System''; and AP-3.11Q, ''Technical Reports''. The objective of this report is to establish the requirements that provide for facility nuclear safety and a proper level of personnel safety and property protection from the effects of fire and the adverse effects of fire-extinguishing agents.

Richard C. Logan

2001-07-30T23:59:59.000Z

377

Optimal joule heating of the subsurface  

DOE Patents (OSTI)

A method for simultaneously heating the subsurface and imaging the effects of the heating is disclosed. This method combines the use of tomographic imaging (electrical resistance tomography or ERT) to image electrical resistivity distribution underground, with joule heating by electrical currents injected in the ground. A potential distribution is established on a series of buried electrodes resulting in energy deposition underground which is a function of the resistivity and injection current density. Measurement of the voltages and currents also permits a tomographic reconstruction of the resistivity distribution. Using this tomographic information, the current injection pattern on the driving electrodes can be adjusted to change the current density distribution and thus optimize the heating. As the heating changes conditions, the applied current pattern can be repeatedly adjusted (based on updated resistivity tomographs) to affect real time control of the heating.

Berryman, J.G.; Daily, W.D.

1994-07-05T23:59:59.000Z

378

Optimal joule heating of the subsurface  

DOE Patents (OSTI)

A method for simultaneously heating the subsurface and imaging the effects of the heating. This method combines the use of tomographic imaging (electrical resistance tomography or ERT) to image electrical resistivity distribution underground, with joule heating by electrical currents injected in the ground. A potential distribution is established on a series of buried electrodes resulting in energy deposition underground which is a function of the resistivity and injection current density. Measurement of the voltages and currents also permits a tomographic reconstruction of the resistivity distribution. Using this tomographic information, the current injection pattern on the driving electrodes can be adjusted to change the current density distribution and thus optimize the heating. As the heating changes conditions, the applied current pattern can be repeatedly adjusted (based on updated resistivity tomographs) to affect real time control of the heating.

Berryman, James G. (Danville, CA); Daily, William D. (Livermore, CA)

1994-01-01T23:59:59.000Z

379

Corrective Action Investigation Plan for Corrective Action Unit 447: Project Shoal Area, Nevada Subsurface Site  

SciTech Connect

This Corrective Action Investigation Plan (CAIP) describes the US Department of Energy's (DOE's) continued environmental investigation of the subsurface Project Shoal Area (PSA) Corrective Action Unit (CAU) 447. The PSA is located in the Sand Springs Mountains in Churchill County, Nevada, about 48 kilometers (km) (30 miles [mi]) southeast of Fallon, Nevada. Project Shoal was part of the Vela Uniform Program which was conducted to improve the US' ability to detect, identify, and locate underground nuclear detonations. The test consisted of detonating a 12-kiloton nuclear device deep underground in granitic rock to determine whether seismic waves produced by an underground nuclear test could be differentiated from seismic waves produced by a naturally occurring earthquake. The test was a joint effort conducted by the US Atomic Energy Commission (AEC) and the US Department of Defense (DoD) in October 1963 (AEC, 1964).

DOE /NV

1998-11-01T23:59:59.000Z

380

The Effect of Heterogeneity on Matrix Acidizing of Carbonate Rocks  

E-Print Network (OSTI)

In matrix acidizing, the goal is to dissolve minerals in the rock to increase well productivity. This is accomplished by injecting an application-specific solution of acid into the formation at a pressure between the pore pressure and fracture pressure. A hydrochloric acid solution is used in carbonate reservoirs, which actually dissolves the calcite rock matrix in the form of conductive channels called wormholes. These wormholes propagate from the wellbore out into the reservoir, bypassing the damaged zone. In matrix acidizing of carbonates, there are four parameters that affect performance: the concentration of calcite present, injection rate of the acid, reaction type, and heterogeneity. Of these parameters, this paper will focus on how rock heterogeneity affects performance. To do this, a coreflood and acidizing apparatus was used to acidize heterogeneous limestone core samples. Rock characterizations and volumetric measurements were considered with the results from these experiments, which made it possible to correlate and quantify the results with rock and volume parameters. It was found that the core samples with more and larger heterogeneities generally required less acid (measured in pore volumes) to achieve breakthrough, that is, a wormhole created axially from one end of the core to the other. This value for pore volumes to breakthrough was one to two orders of magnitude less than more homogeneous samples. The general procedure and best practices for acidizing the core samples is also detailed in this thesis. This procedure was followed for preparation, coreflooding, and acidizing for all core samples.

Keys, Ryan S.

2009-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "fractured subsurface rock" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Effects of dry fractures on matrix diffusion in unsaturated fractured rocks  

E-Print Network (OSTI)

Moridis, G. and Q. Hu, Radionuclide transport models underAn important factor in radionuclide retardation? J. Geophys.and G. Y. Bussod, Radionuclide transport in the unsaturated

Seol, Yongkoo; Liu, Hui Hai; Bodvarsson, Gudmundur S.

2002-01-01T23:59:59.000Z

382

Session: Hot Dry Rock  

DOE Green Energy (OSTI)

This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of four presentations: ''Hot Dry Rock - Summary'' by George P. Tennyson, Jr.; ''HDR Opportunities and Challenges Beyond the Long Term Flow Test'' by David V. Duchane; ''Start-Up Operations at the Fenton Hill HDR Pilot Plant'' by Raymond F. Ponden; and ''Update on the Long-Term Flow Testing Program'' by Donald W. Brown.

Tennyson, George P. Jr.; Duchane, David V.; Ponden, Raymond F.; Brown, Donald W.

1992-01-01T23:59:59.000Z

383

Extended analysis of constant-height hydraulic fractures for the estimation of in-situ crack-opening modulus from bottomhole pressure records  

DOE Green Energy (OSTI)

Hydraulic fractures created in oil and gas bearing rock formations can be made to propagate for a limited time at approximately constant height if favorable stress, deformation modulus or fracture toughness barriers to height growth exist and if the fracture design is suitably optimized to exploit these favorable conditions and reduce height growth. In this report, a unified theoretical formulation for the Perkins-Kern-Nordgren (PKN) and Christianovitch-Geertsma-De Klerk-Daneshy (CGDD) constant height fracture models is first presented. For a fracture fluid injection rate that varies as an arbitrary power of time, growth laws for fracturing fluid pressure, fracture width, and flow rate are rigorously derived for PKN and CGDD types of fractures. These similarity solutions account for non-Newtonian power-law fluid flow, transient fluid storage and generalized power-law fluid leak-off to the rock formation. They include and extend the results currently available in the literature for PKN and CGDD fractures. The results for PKN and CGDD fractures are then generalized to obtain an approximate hybrid CGDD-PKN fracture model that can be applied to constant height fractures of arbitrary length/height aspect ratio and arbitrary cross-sectional shape. Characteristic times for fracture extension are identified and estimates are given for the transition times when the fracture evolves from a CGDD-type fracture at small aspect ratio to a PKN-type fracture at large aspect ratio. These results are useful for interpreting fracturing data and for designing fractures for crack-opening modulus measurements.

Wijesinghe, A.M.

1987-03-01T23:59:59.000Z

384

A Rare Isolated Trapezoid Fracture  

E-Print Network (OSTI)

Toh S, Tsubo K, et al. An occult fracture of the trapezoiddue to concern for an occult fracture revealed a comminuted

Afifi, Negean; Lu, Jenny J

2011-01-01T23:59:59.000Z

385

EVALUATION OF ENHANCED VOC REMOVAL WITH SOIL FRACTURING IN THE SRS UPLAND UNIT  

Science Conference Proceedings (OSTI)

The Environmental Restoration Technology Section (ERTS) of the Savannah River National Laboratory (SRNL) conducted pilot scale testing to evaluate the effectiveness of using hydraulic fracturing as a means to improve soil vapor extraction (SVE) system performance. Laboratory and field research has shown that significant amounts of solvents can be entrapped in low permeability zones by capillary forces and removal by SVE can be severely limited due to low flow rates, mass transfer resistance of the hydrophobic compounds by trapped interparticle water, and diffusion resistance. Introducing sand-filled fractures into these tight zones improves the performance of SVE by (1) increasing the overall permeability of the formation and thereby increasing SVE flow rates, (2) shortening diffusion pathways, and (3) increasing air permeability by improving pore water removal. The synergistic effect of the fracture well completion methods, fracture and flow geometry, and pore water removal appears to increase the rate of solvent mass removal over that of increasing flow rate alone. A field test was conducted where a conventional well in the SRS Upland Unit was tested before and after hydraulic fracturing. ERTS teamed with Clemson University through the South Carolina University and Education Foundation (SCUREF) program utilizing their expertise in fracturing and fracture modeling. The goals of the fracturing pilot testing were to evaluate the following: (1) The effect of hydraulic fractures on the performance of a conventional well. This was the most reliable way to remove the effects of spatial variations in permeability and contaminant distribution on relative well performance. It also provided data on the option of improving the performance of existing wells using hydraulic fractures. (2) The relative performance of a conventional SVE well and isolated hydraulic fractures. This was the most reliable indicator of the performance of hydraulic fractures that could be created in a full-scale implementation. The SVE well, monitoring point arrays and four fracturing wells were installed and the well testing has been completed. Four fractures were successfully created the week of July 25, 2005. The fractures were created in an open area at the bottom of steel well casing by using a water jet to create a notch in the soil and then injecting a guar-sand slurry into the formation. The sand-filled fractures increase the effective air permeability of the subsurface formation diffusion path lengths for contaminant removal. The primary metrics for evaluation were an increase in SVE flow rates in the zone of contamination and an increase in the zone of influence. Sufficient testing has been performed to show that fracturing in the Upland Unit accelerates SVE solvent remediation and fracturing can increase flow rates in the Upland Unit by at least one order of magnitude.

Riha, B

2005-10-31T23:59:59.000Z

386

Hot Dry Rock Geothermal Energy Development Project. Annual report, fiscal year 1977  

DOE Green Energy (OSTI)

The feasibility of extracting geothermal energy from hot dry rock in the earth's crust was investigated. The concept being investigated involves drilling a deep hole, creating an artificial geothermal reservoir at the bottom of the hole by hydraulic fracturing, and then intersecting the fracture with a second borehole. At the beginning of FY77, the downhole system was complete, but the impedance to the flow of fluid was too high to proceed confidently with the planned energy extraction demonstration. Therefore, in FY77 work focused on an intensive investigation of the characteristics of the downhole system and on the development of the necessary tools and techniques for understanding and improving it. Research results are presented under the following section headings: introduction and history; hot dry rock resource assessment and site selection; instrumentation and equipment development; drilling and fracturing; reservoir engineering; energy extraction system; environmental studies; project management and liaison; and, looking back and ahead. (JGB)

Not Available

1978-02-01T23:59:59.000Z

387

Regional Analysis and Characterization of Fractured Aquifers in the Virginia Blue Ridge and Piedmont Provinces  

SciTech Connect

Areas related to low-temperature geothermal applications include the recognition of and exploration for deep fracture permeability in crystalline rocks. It is well known that the best currently available downhole techniques to identify the locations of fracture zones in crystalline rocks depend upon the measurement of some thermal parameter such as temperature or heat flow. The temperature-depth profiles and their derivatives provide a direct indication of those fracture zones that conduct water. The exploration for new groundwater resources is considered by many to be the new frontier in the general field of hydrology. The availability of adequate groundwater resources in fractured rocks is a major concern in many areas of the eastern US as well as in the other parts of the world. A geothermal database can therefore become an important source of basic data that can be used to help characterize the nature and extent of hydraulic conductivity in fractured rocks. We plan to continue to augment our web site (http://rglsun1.geol.vt.edu) with new geothermal data as the data become available, and to advertise the increasing residential uses of geothermal energy in the eastern US. This work was originally titled ''Archival of Geothermal Exploration Data,'' and was initiated to make available to the public the extensive geothermal database for the southeastern US. These data include plots of temperature and geothermal gradient logs, scans of 7.5-min quadrangles where appropriate, and annotated location maps.

Costain, J.K.

2000-07-25T23:59:59.000Z

388

Characterisation of hydraulic fractures in limestones using X-ray microtomography  

E-Print Network (OSTI)

Hydraulic tension fractures were produced in porous limestones using a specially designed hydraulic cell. The 3D geometry of the samples was imaged using X-ray computed microtomography before and after fracturation. Using these data, it was possible to estimate the permeability tensor of the core samples, extract the path of the rupture and compare it to the heterogeneities initially present in the rock.

Renard, Francois; Desrues, Jacques; Plougonven, Erwan; Ougier-Simonin, Audrey

2006-01-01T23:59:59.000Z

389

Fracture orientation analysis by the solid earth tidal strain method | Open  

Open Energy Info (EERE)

orientation analysis by the solid earth tidal strain method orientation analysis by the solid earth tidal strain method Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Fracture orientation analysis by the solid earth tidal strain method Details Activities (1) Areas (1) Regions (0) Abstract: A new practical method has been developed to estimate subsurface fracture orientation based on an analysis of solid earth tidal strains. The tidal strain fracture orientation technique is a passive method which has no depth limitation. The orientation of either natural or hydraulically stimulated fractures can be measured using either new or old static observation wells. Estimates for total compressibility and areal interconnected porosity can also be developed for reservoirs with matrix permeability using a combination of tidal and barometric strain analysis.

390

Stress and fault rock controls on fault zone hydrology, Coso geothermal  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Stress and fault rock controls on fault zone hydrology, Coso geothermal field, CA Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: Stress and fault rock controls on fault zone hydrology, Coso geothermal field, CA Details Activities (1) Areas (1) Regions (0) Abstract: In crystalline rock of the Coso Geothermal Field, CA, fractures are the primary source of permeability. At reservoir depths, borehole image, temperature, and mud logs indicate fluid flow is concentrated in extensively fractured damage zones of large faults well-oriented for slip.

391

Simulation of rock blasting with the SHALE code  

SciTech Connect

The SHALE code and its special features for simulating rock blasting are described. SHALE first simulates the detonation of the explosive and then follows the effect of the resulting shocks and stress waves on the surrounding rock. A general description is given for SHALE as a finite-difference stress-wave-propagation code, followed by a brief discussion of numerical methods, and a section on the treatment of the explosive. The constitutive model in SHALE is the BCM (Bedded Crack Model), which describes the response of the rock, including fracture. The use of SHALE is illustrated in a discussion of the basic phenomenology of crater blasting, as seen in simulations of field experiments in oil shale. Predicted peak surface velocities are found to agree with field measurements. Comparisons between predicted fracture and observed craters give insight into the relative roles played by shock waves and the high-pressure-explosive product gases. The two-dimensional version of SHALE is being documented and will be available for use by other investigators. A three-dimensional version is planned.

Adams, T.F.; Demuth, R.B.; Margolin, L.G.; Nichols, B.D.

1983-01-01T23:59:59.000Z

392

Progress of the US Hot-Dry-Rock Program  

DOE Green Energy (OSTI)

While other geologic environments and possible heat-extraction methods are recognized, the US Hot Dry Rock (HDR) Program has so far concentrated on the use of hydraulic fracturing to create flow passages and heat-transfer surface between two wells drilled into hot crystalline rock of low initial permeability. A recirculating pressurized-water loop has been used at Fenton Hill, New Mexico, to extract heat at rates up to 5MW(t) from a system of this type in granitic rock at a depth of 2600 m. The two wells for a larger, deeper, hotter system have now been drilled at the same location. They will be connected during 1982 by a set of hydraulic fractures, and the resulting heat-extraction loop is expected to yield the engineering experience and performance data required to demonstrate the commercial usefulness of such systems. Meanwhile, an evaluation of the HDR resource base of the United States is continuing, together with detailed investigation of local areas that appear especially promisng either for future heat-extraction experiments or for eventual commercial development.

Smith, M.C.

1982-01-01T23:59:59.000Z

393

Pressure testing of a high temperature naturally fractured reservoir  

DOE Green Energy (OSTI)

Los Alamos National Laboratory has conducted a number of pumping and flow-through tests at the Hot Dry Rock (HDR) test site at Fenton Hill, New Mexico. These tests consisted of injecting fresh water at controlled rates up to 12 BPM (32 l/s) and surface pressures up to 7000 psi (48 MPa) into the HDR formation at depths from 10,000 to 13,180 feet (3050 to 4000 m). The formation is a naturally fractured granite at temperatures of about 250/sup 0/C. The matrix porosity is <1% and permeability is on the order of 1 nD. Hence most of the injected fluid is believed to move through fractures. There has been no evidence of fracture breakdown phenomena, and hence it is believed that preexisting joints in the formation are opened by fluid injection. Water losses during pumping are significant, most likely resulting from flow into secondary fractures intersecting the main fluid conducting paths. The pressure-time response observed in these tests can be interpreted in terms of non-isothermal, fracture-dominated flow. As the fluid pressure increases from small values to those comparable to fracturing pressures, the formation response changes from linear fracture flow to the highly nonlinear situation where fracture lift-off occurs. A numerical heat and mass flow model was used to match the observed pressure response. Good matches were obtained for pressure buildup and shut-in data by assigning pressure dependent fracture and leak-off permeabilities. 12 refs., 5 figs., 2 tabs.

Kelkar, S.M.; Zyvoloski, G.A.; Dash, Z.V.

1986-01-01T23:59:59.000Z

394

Effective fracture geometry obtained with large water sand ratio  

E-Print Network (OSTI)

Shale gas formation exhibits some unusual reservoir characteristics: nano-darcy matrix permeability, presence of natural fractures and gas storage on the matrix surface that makes it unique in many ways. It’s difficult to design an optimum fracture treatment for such formation and even more difficult is to describe production behavior using a reservoir model. So far homogeneous, two wing fracture, and natural fracture models have been used for this purpose without much success. Micro seismic mapping technique is used to measure the fracture propagation in real time. This measurement in naturally fractured shale formation suggests a growth of fracture network instead of a traditional two wing fractures. There is an industry wise consensus that fracture network plays an important role in determining the well productivity of such formations. A well with high density of fracture networks supposed to have better productivity. Shale formations have also exhibited production pattern which is very different from conventional or tight gas reservoir. Initial flow period is marked by steep decline in production while the late time production exhibits a slow decline. One of the arguments put for this behavior is linear flow from a bi-wing fractured well at early time and contribution of adsorbed gas in production at late time. However, bi-wing fracture geometry is not supported by the micro-seismic observation. A realistic model should include both the fracture network and adsorbed gas property. In this research we have proposed a new Power Law Permability model to simulate fluid flow from hydraulically fractured Shale formation. This model was first described by Valko & Fnu (2002) and used for analyzing acid treatment jobs. The key idea of this model is to use a power law permeability function that varies with the radial distance from well bore. Scaling exponent of this power law function has been named power law index. The permeability function has also been termed as secondary permeability. This work introduces the method of Laplace solution to solve the problem of transient and pseudo steady-state flow in a fracture network. Development and validation of this method and its extension to predict the pressure (and production) behaviour of fracture network were made using a novel technic. Pressure solution was then combined with material balance through productivity index to make production forecast. Reservoir rock volume affected by the fracture stimulation treatment that contributes in the production is called effective stimulated volume. This represents the extent of fracture network in this case. Barnett shale formation is a naturally fractured shale reservoir in Fort Worth basin. Several production wells from this formation was analysed using Power Law Model and it was found that wells productivity are highly dependent on stimulated volume. Apparently the wells flow under pseudo steady state for most part of their producing life and the effect of boundary on production is evident in as soon as one months of production. Due to short period of transient flow production from Barnett formations is expected to be largely independent of the relative distribution of permeability and highly dependent on the stimulated area and induced secondary permeability. However, an indirect relationship between permeability distribution and production rate is observed. A well with low power law index shows a better (more even) secondary permeability distribution in spatial direction, larger stimulated volume and better production. A comparative analysis between the new model and traditional fracture model was made. It was found that both models can be used successfully for history matching and production forecasting from hydraulically fractured shale gas formation.

Kumar, Amrendra

2008-12-01T23:59:59.000Z

395

Hydraulic Fracture Optimization with a Pseudo-3D Model in Multi-layered Lithology  

E-Print Network (OSTI)

Hydraulic Fracturing is a technique to accelerate production and enhance ultimate recovery of oil and gas while fracture geometry is an important aspect in hydraulic fracturing design and optimization. Systematic design procedures are available based on the so-called two-dimensional models (2D) focus on the optimization of fracture length and width, assuming one can estimate a value for fracture height, while so-called pseudo three dimensional (p-3D) models suitable for multi-layered reservoirs aim to maximize well production by optimizing fracture geometry, including fracture height, half-length and width at the end of the stimulation treatment. The proposed p-3D approach to design integrates four parts: 1) containment layers discretization to allow for a range of plausible fracture heights, 2) the Unified Fracture Design (UFD) model to calculate the fracture half-length and width, 3) the PKN or KGD models to predict hydraulic fracture geometry and the associated net pressure and other treatment parameters, and, finally, 4) Linear Elastic Fracture Mechanics (LEFM) to calculate fracture height. The aim is to find convergence of fracture height and net pressure. Net pressure distribution plays an important role when the fracture is propagating in the reservoir. In multi-layered reservoirs, the net pressure of each layer varies as a result of different rock properties. This study considers the contributions of all layers to the stress intensity factor at the fracture tips to find the final equilibrium height defined by the condition where the fracture toughness equals the calculated stress intensity factor based on LEFM. Other than maximizing production, another obvious application of this research is to prevent the fracture from propagating into unintended layers (i.e. gas cap and/or aquifer). Therefore, this study can aid fracture design by pointing out: (1) Treating pressure needed to optimize fracture geometry, (2) The containment top and bottom layers of a multi-layered reservoir, (3) The upwards and downwards growth of the fracture tip from the crack center.

Yang, Mei

2011-08-01T23:59:59.000Z

396

A semi-analytical method for heat sweep calculations in fractured reservoirs  

DOE Green Energy (OSTI)

An analytical approximation is developed for purely conductive heat transfer from impermeable blocks of rock to fluids sweeping past the rocks in fractures. The method was incorporated into a multi-phase fluid and heat flow simulator. Comparison with exact analytical solutions and with simulations using a multiple interacting continua approach shows very good accuracy, with no increase in computing time compared to porous medium simulations. 14 refs., 3 figs., 5 tabs.

Pruess, K.; Wu, Y.S.

1988-01-01T23:59:59.000Z

397

The importance of in-situ-stress profiles in hydraulic-fracturing applications  

Science Conference Proceedings (OSTI)

In-situ stresses define the local forces acting on lithologic layers in the subsurface. Knowledge of these stresses is important in drilling, wellbore-stability, and, especially, hydraulic-fracturing applications. The measurement of in-situ stress is not straightforward and, therefore, often goes unmeasured. As such, one often assumes values of in-situ stress or estimate in-situ stresses from logging parameters. This article illustrates the importance of in-situ-stress estimates as they relate to hydraulic fracturing and outlines several techniques for estimating in-situ-stress magnitudes.

Hopkins, C.W. [S.A. Holditch and Associates, Inc., Houston, TX (United States). Houston Div.

1997-09-01T23:59:59.000Z

398

Single fracture aperture patterns: Characterization by slit-island fractal analysis  

Science Conference Proceedings (OSTI)

Single fracture measurements are difficult to obtain, but they are the only means we have to observe and study natural fracture morphology. The character of the fracture openings (apertures) is often one of the primary factors controlling fluid flow in the fracture. In particular, the shape, distribution, and connectivity of contact areas and flow channels can affect the relative permeability of wetting and non-wetting fluid phases in unsaturated systems. In this paper we use three methods of fractal analysis (the slit-island, the divider, and the variogram) as well as statistical and geostatistical analysis to characterize the geometry of measured fracture apertures obtained from two different fractured rock specimens from the field. One of these is a granitic fracture (crack) of homogeneous lithology and no displacement, the other is a fracture (fault) obtained from a highly altered fault zone, containing striations and slickensides. We discuss the fractal and geostatistical analysis of these two fractures in the context of what information is most helpful for making predictions about fluid flow in single fractures.

Cox, B.L.; Wang, J.S.Y.

1993-01-01T23:59:59.000Z

399

Vaporizing Flow in Hot Fractures: Observations from Laboratory Experiments  

DOE Green Energy (OSTI)

Understanding water seepage in hot fractured rock is important in a number of fields including geothermal energy recovery and nuclear waste disposal. Heat-generating high-level nuclear waste packages which will be emplaced in the partially saturated fractured tuffs at the potential high-level nuclear waste repository at Yucca Mountain, Nevada, if it becomes a high-level nuclear waste repository, will cause significant impacts on moisture distribution and migration. Liquid water, which occupies anywhere from 30 to 100% of the porespace, will be vaporized as the temperature reaches the boiling temperature. Flowing primarily in fractures, the vapor will condense where it encounters cooler rock, generating mobile water. This water will flow under gravitational and capillary forces and may flow back to the vicinity of the emplaced waste where it may partially escape vaporization. Water flowing down (sub-) vertical fractures may migrate considerable distances through fractured rock that is at above-boiling temperatures; thus, flowing condensate may contact waste packages, and provide a pathway for the transport of water-soluble radionuclides downward to the saturated zone. Thermally-driven flow processes induced by repository heat may be as important or even more important for repository performance than natural infiltration. For a nominal thermal loading of 57 kW/acre, vaporization may generate an average equivalent percolation flux from condensate of 23.1 mm/yr over 1,000 years, and 5.2 mm/yr over 10,000 years. These numbers are comparable to or larger than current estimates of net infiltration at Yucca Mountain. This condensate, which is generated in the immediate vicinity (meters) of the waste packages, will likely have a larger impact on waste package and repository performance than a similar amount of water introduced at the land surface.

Kneafsey, T.; Pruess, K.

1998-12-01T23:59:59.000Z

400

Evaluation of the relationship between fracture conductivity, fracture fluid production, and effective fracture length  

E-Print Network (OSTI)

Low-permeability gas wells often produce less than predicted after a fracture treatment. One of the reasons for this is that fracture lengths calculated after stimulation are often less than designed lengths. While actual fracture lengths may be shorter due to fracture growth out of zone, improper proppant settling, or proppant flowback, short calculated fracture lengths can also result from incorrect analysis techniques. It is known that fracturing fluid that remains in the fracture and formation after a hydraulic fracture treatment can decrease the productivity of a gas well by reducing the relative permeability to gas in the region invaded by this fluid. However, the relationships between fracture fluid cleanup, effective fracture length, and well productivity are not fully understood. In this work I used reservoir simulation to determine the relationship between fracture conductivity, fracture fluid production, effective fracture length, and well productivity. I simulated water saturation and pressure profiles around a propped fracture, tracked gas production along the length of the propped fracture, and quantified the effective fracture length (i.e., the fracture length under single-phase flow conditions that gives similar performance as for multiphase flow conditions), the "cleanup" fracture length (i.e., the fracture length corresponding to 9