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1

Structural Settings Of Hydrothermal Outflow- Fracture Permeability...  

Open Energy Info (EERE)

Settings Of Hydrothermal Outflow- Fracture Permeability Maintained By Fault Propagation And Interaction Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal...

2

Relative Permeability of Fractured Rock  

SciTech Connect (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

3

Relative Permeability of Fractured Rock  

E-Print Network [OSTI]

, and by the Department of Petroleum Engineering, Stanford University Stanford Geothermal Program Interdisciplinary Research in Engineering and Earth Sciences STANFORD UNIVERSITY Stanford, California #12;#12;v Abstract fractures and various fluids have yielded different relative permeability-saturation relations. This study

Stanford University

4

Fracture permeability and seismic wave scattering ŒPoroelastic ...  

E-Print Network [OSTI]

Jun 18, 2010 ... The new model contains fracture permeability in the plan-parallel direction. ... Division of Chemical Sciences of the U.S. Department of Energy ...

Seiji Nakagawa

2010-02-03T23:59:59.000Z

5

Structural Settings Of Hydrothermal Outflow- Fracture Permeability  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revisionEnvReviewNonInvasiveExplorationUT-g GrantAtlas (PACAOpen EnergyInsulated Panel Association (SIPA) Jump

6

Reservoir-Scale Fracture Permeability in the Dixie Valley, Nevada...  

Open Energy Info (EERE)

Reservoir-Scale Fracture Permeability in the Dixie Valley, Nevada, Geothermal Field Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Paper:...

7

Fracture permeability and seismic wave scattering--Poroelastic linear-slip interface model for heterogeneous fractures  

SciTech Connect (OSTI)

Schoenberg's Linear-slip Interface (LSI) model for single, compliant, viscoelastic fractures has been extended to poroelastic fractures for predicting seismic wave scattering. However, this extended model results in no impact of the in-plane fracture permeability on the scattering. Recently, we proposed a variant of the LSI model considering the heterogeneity in the in-plane fracture properties. This modified model considers wave-induced, fracture-parallel fluid flow induced by passing seismic waves. The research discussed in this paper applies this new LSI model to heterogeneous fractures to examine when and how the permeability of a fracture is reflected in the scattering of seismic waves. From numerical simulations, we conclude that the heterogeneity in the fracture properties is essential for the scattering of seismic waves to be sensitive to the permeability of a fracture.

Nakagawa, S.; Myer, L.R.

2009-06-15T23:59:59.000Z

8

Low permeability gas reservoir production using large hydraulic fractures  

E-Print Network [OSTI]

extending up to three thousand feet from the producing well. Also, a model simulating a nuclear cavity was designed. This model simulated a well containing an eighty foot radius cavity with a fractured zone of one hundred times the reservoir permeability... of each system was prepared. The results of this study showed that all fractures of greater than one thousand foot radius had greater productivity and greater cumu- lative gas produced than did the nuclear cavity. It appears that large hydraulic...

Holditch, Stephen A

1970-01-01T23:59:59.000Z

9

A New Coal-Permeability Model: Internal Swelling Stress and Fracture–Matrix Interaction  

E-Print Network [OSTI]

L. : Adsorption-induced coal swelling and stress:acid gas sequestration into coal seams. J Geophys. Res. (fracturing on permeability of coal. Min. Sci. Technol. 3,

Liu, Hui-Hai; Rutqvist, Jonny

2010-01-01T23:59:59.000Z

10

3.3 NUMERICAL MODELING OF SOLID DEFORMATION AND STRESS-DEPENDENT PERMEABILITY IN NATURALLY FRACTURED  

E-Print Network [OSTI]

permeability. When the pore pressure depletes due to oil/gas production rates in highly stress FRACTURED RESERVOIRS During the first year of this project, we analyzed the productivity behavior was demonstrated. 3.3.1 Introduction Fractures are the main fluid flow paths in naturally fractured reservoirs

Schechter, David S.

11

Numerical modeling of hydraulic fracture problem in permeable medium using cohesive zone model  

E-Print Network [OSTI]

Numerical modeling of hydraulic fracture problem in permeable medium using cohesive zone model-off dominated. We demonstrate the ability of our cohesive zone model in simulating the hydraulic fracture in all these propagation regimes. Keywords: Hydraulic fracture, Cohesive zone model, Finite element analysis, Hydro

Paris-Sud XI, Université de

12

Stress- and Chemistry-Mediated Permeability Enhancement/Degradation in Stimulated Critically-Stressed Fractures  

SciTech Connect (OSTI)

This work has investigated the interactions between stress and chemistry in controlling the evolution of permeability in stimulated fractured reservoirs through an integrated program of experimentation and modeling. Flow-through experiments on natural and artificial fractures in Coso diorite have examined the evolution of permeability under paths of mean and deviatoric stresses, including the role of dissolution and precipitation. Models accommodating these behaviors have examined the importance of incorporating the complex couplings between stress and chemistry in examining the evolution of permeability in EGS reservoirs. This document reports the findings of experiment [1,2] and analysis [3,4], in four sequential chapters.

Derek Elsworth; Abraham S. Grader; Chris Marone; Phillip Halleck; Peter Rose; Igor Faoro; Joshua Taron; André Niemeijer; Hideaki Yasuhara

2009-03-30T23:59:59.000Z

13

An experimental study of the permeability of fracture intersections in Sioux quartzite  

E-Print Network [OSTI]

at the intersection. The comminution of proppants at high confining pressure in such specimens probably causes the larger percentage (and sometimes absolute) reduction in permeability relative to comparable cohesive specimens. DEDICATION To My Parents Michael... the fractures than do the FCS (Figure 1Zd and a). 4) In a deformed single-fracture FNCS (Figure 12e), proppants appear to be crushed between the fracture surfaces. 5) The intersection in the FNCS (Figure 12f, Experiment 38) is offset about 0. 5 mm...

Juddo, Edward Paul

1986-01-01T23:59:59.000Z

14

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

SciTech Connect (OSTI)

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

15

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

SciTech Connect (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. 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

16

Fracture permeability and seismic wave scattering--Poroelastic linear-slip interface model for heterogeneous fractures  

E-Print Network [OSTI]

modeling of faults and fractures: Geophysics, 60, 1514-1526.Poroelastic modeling of fracture-seismic wave interaction:by a heterogeneous fracture: J. Acoust. Soc. Am. , 115,

Nakagawa, S.

2010-01-01T23:59:59.000Z

17

A new coal-permeability model: Internal swelling stress and fracture-matrix interaction  

SciTech Connect (OSTI)

We have developed a new coal-permeability model for uniaxial strain and constant confining stress conditions. The model is unique in that it explicitly considers fracture-matrix interaction during coal deformation processes and is based on a newly proposed internal-swelling stress concept. This concept is used to account for the impact of matrix swelling (or shrinkage) on fracture-aperture changes resulting from partial separation of matrix blocks by fractures that do not completely cut through the whole matrix. The proposed permeability model is evaluated with data from three Valencia Canyon coalbed wells in the San Juan Basin, where increased permeability has been observed during CH{sub 4} gas production, as well as with published data from laboratory tests. Model results are generally in good agreement with observed permeability changes. The importance of fracture-matrix interaction in determining coal permeability, demonstrated in this work using relatively simple stress conditions, underscores the need for a dual-continuum (fracture and matrix) mechanical approach to rigorously capture coal-deformation processes under complex stress conditions, as well as the coupled flow and transport processes in coal seams.

Liu, H.H.; Rutqvist, J.

2009-10-01T23:59:59.000Z

18

A Permeability Model for Coal and Other Fractured, Sorptive-Elastic Media  

SciTech Connect (OSTI)

This paper describes the derivation of a new equation that can be used to model the permeability behavior of a fractured, sorptive-elastic medium, such as coal, under variable stress conditions. The equation is applicable to confinement pressure schemes commonly used during the collection of permeability data in the laboratory. The model is derived for cubic geometry under biaxial or hydrostatic confining pressures. The model is designed to handle changes in permeability caused by adsorption and desorption of gases onto and from the matrix blocks in fractured media. The model equations can be used to calculate permeability changes caused by the production of methane (CH4) from coal as well as the injection of gases, such as carbon dioxide, for sequestration in coal. Sensitivity analysis of the model found that each of the input variables can have a significant impact on the outcome of the permeability forecast as a function of changing pore pressure; thus, accurate input data are essential. The permeability model also can be used as a tool to determine input parameters for field simulations by curve fitting laboratory-generated permeability data. The new model is compared to two other widely used coal-permeability models using a hypothetical coal with average properties.

Eric P. Robertson; Richard L. Christiansen

2008-09-01T23:59:59.000Z

19

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

SciTech Connect (OSTI)

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

20

Modeling Mud-Filtrate Invasion Effects on Resistivity Logs to Estimate Permeability of Vuggy and Fractured Carbonate Formations  

E-Print Network [OSTI]

SPE 121136 Modeling Mud-Filtrate Invasion Effects on Resistivity Logs to Estimate Permeability to diagnose and estimate secondary porosity and absolute permeability of fractured and vuggy carbonate-connected) and fractured porosity, all embedded in a tight matrix. Rock-core data and wellbore resistivity images indicate

Torres-Verdín, Carlos

Note: This page contains sample records for the topic "outflow fracture permeability" 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

CHARACTERIZATION OF IN-SITU STRESS AND PERMEABILITY IN FRACTURED RESERVOIRS  

SciTech Connect (OSTI)

Expanded details and additional results are presented on two methods for estimating fracture orientation and density in subsurface reservoirs from scattered seismic wavefield signals. In the first, fracture density is estimated from the wavenumber spectra of the integrated amplitudes of the scattered waves as a function of offset in pre-stack data. Spectral peaks correctly identified the 50m, 35m, and 25m fracture spacings from numerical model data using a 40Hz source wavelet. The second method, referred to as the Transfer Function-Scattering Index Method, is based upon observations from 3D finite difference modeling that regularly spaced, discrete vertical fractures impart a ringing coda-type signature to any seismic energy that is transmitted through or reflected off of them. This coda energy is greatest when the acquisition direction is parallel to the fractures, the seismic wavelengths are tuned to the fracture spacing, and when the fractures have low stiffness. The method uses surface seismic reflection traces to derive a transfer function, which quantifies the change in an apparent source wavelet propagating through a fractured interval. The transfer function for an interval with low scattering will be more spike-like and temporally compact. The transfer function for an interval with high scattering will ring and be less temporally compact. A Scattering Index is developed based on a time lag weighting of the transfer function. When a 3D survey is acquired with a full range of azimuths, the Scattering Index allows the identification of subsurface areas with high fracturing and the orientation (or strike) of those fractures. The method was calibrated with model data and then applied to field data from a fractured reservoir giving results that agree with known field measurements. As an aid to understanding the scattered wavefield seen in finite difference models, a series of simple point scatterers was used to create synthetic seismic shot records collected over regular, discrete, vertical fracture systems. The model contains a series of point scatterers delineating the top tip and bottom tip of each vertical fracture. When the shot record is located in the middle of the fractured zone and oriented normal to the direction of fracturing, a complicated series of beating is observed in the back scattered energy. When the shot record is oriented parallel to the fracturing, ringing wavetrains are observed with moveouts similar to reflections from many horizontal layers. These results are consistent with the full 3D elastic modeling results. An AVOA analysis method was refined and applied to a field data set. An iterative, nonlinear least squares inversion that uses the Gauss-Newton method and analyzes the full range of azimuths simultaneously was employed. Resulting fracture location and strike orientation estimates are consistent with other fracture information from the area. Two modeling approaches for estimating permeability values from seismically derived fracture parameters have been investigated. The first is a statistical method that calculates the permeability tensor for a given distribution of fractures. A possible workflow using this method was tested on fracture distributions obtained from the Transfer Function-Scattering Index analysis method. Fracture aperture and length estimates are needed for this method. The second method is a direct flow model of discrete fractures and fracture networks using a computational fluid dynamics code. This tool provides a means of visualizing flow in fracture networks and comparing expressions for equivalent fracture aperture flow to the actual flow. A series of two dimensional models of fractures and fracture networks, as well as a 3-D model of a single rough fracture, were tested.

Daniel R. Burns; M. Nafi Toksoz

2004-07-19T23:59:59.000Z

22

Permeability changes due to mineral diagenesis in fractured crust: implications for hydrothermal circulation at  

E-Print Network [OSTI]

The hydrothermal processes at ridge crests have been extensively studied during the last two decades. NeverthelessPermeability changes due to mineral diagenesis in fractured crust: implications for hydrothermal, the reasons why hydrothermal fields are only occasionally found along some ridge segments remain a matter

Manga, Michael

23

A Permeability Model for Coal and Other Fractured, Sorptive-Elastic Media  

SciTech Connect (OSTI)

This paper describes the derivation of a new equation that can be used to model the permeability behavior of a fractured, sorptive-elastic media, such as coal, under variable stress conditions commonly used during measurement of permeability data in the laboratory. The model is derived for cubic geometry under biaxial or hydrostatic confining pressures. The model is also designed to handle changes in permeability caused by adsorption and desorption of gases from the matrix blocks. The model equations can be used to calculate permeability changes caused by the production of methane from coal as well as the injection of gases, such as carbon dioxide, for sequestration in coal. Sensitivity analysis of the model found that each of the input variables can have a significant impact on the outcome of the permeability forecast as a function of changing pore pressure; thus, accurate input data are essential. The permeability model can also be used as a tool to determine input parameters for field simulations by curve-fitting laboratory-generated permeability data. The new model is compared to two other widely used coal permeability models using a hypothetical coal with average properties.

Eric P. Robertson; Richard L. Christiansen

2006-10-01T23:59:59.000Z

24

Fracture-enhanced porosity and permeability trends in Bakken Formation, Williston basin, western North Dakota  

SciTech Connect (OSTI)

Fractures play a critical role in oil production from the Bakken Formation (Devonian and Mississippian) in the North Dakota portion of the Williston basin. The Bakken Formation in the study area is known for its low matrix porosity and permeability, high organic content, thermal maturity, and relative lateral homogeneity. Core analysis has shown the effective porosity and permeability development within the Bakken Formation to be related primarily to fracturing. In theory, lineaments mapped on the surface reflect the geometry of basement blocks and the zones of fracturing propagated upward from them. Fracturing in the Williston basin is thought to have occurred along reactivated basement-block boundaries in response to varying tectonic stresses and crustal flexure throughout the Phanerozoic. Landsat-derived lineament maps were examined for the area between 47/degrees/ and 48/degrees/ north lat. and 103/degrees/ and 104/degrees/ west long. (northern Billings and Golden Valley Counties, and western McKenzie County, North Dakota) in an attempt to identify large-scale fracture trends. In the absence of major tectonic deformation in the craton, a subtle pattern of fracturing has propagated upward through the sedimentary cover and emerged as linear topographic features visible on these large-scale, remote-sensed images.

Freisatz, W.B.

1988-07-01T23:59:59.000Z

25

Fractured gas well analysis: evaluation of in situ reservoir properties of low permeability gas wells stimulated by finite conductivity hydraulic fractures  

E-Print Network [OSTI]

FRACTURED GAS WELL ANALYSIS - EVALUATION OF IN SITU RESERVOIR PROPERTIES OF LOW PERMEABILITY GAS WELLS STIMULATED BY FINITE CONDUCTIVITY HYDRAULIC FRACTURES A Thesis by CHARLES ADOIZA MAKOJU Submitted to the Graduate College of Texas AQ1... BY FINITE CONDUCTIVITY HYDRAULIC FRACTURES A Thesis by CHARLES ADOIZA MAKOJU Approved as to style and content by: C a~ an o ommsttee Member Member em er Hea o Department December 1978 ABSTRACT FRACTURED GAS HELL ANALYSIS - EVALUATION OF IN SITU...

Makoju, Charles Adoiza

1978-01-01T23:59:59.000Z

26

Coupled Analysis of Change in Fracture Permeability during the Cooling Phase of the Yucca Mountain Drift Scale Test  

SciTech Connect (OSTI)

This paper presents results from a coupled thermal, hydrological and mechanical analysis of thermally-induced permeability changes during heating and cooling of fractured volcanic rock at the Drift Scale Test at Yucca Mountain, Nevada. The analysis extends the previous analysis of the four-year heating phase to include newly available data from the subsequent four year cooling phase. The new analysis of the cooling phase shows that the measured changes in fracture permeability follows that of a thermo-hydro-elastic model on average, but at several locations the measured permeability indicates (inelastic) irreversible behavior. At the end of the cooling phase, the air-permeability had decreased at some locations (to as low as 0.2 of initial), whereas it had increased at other locations (to as high as 1.8 of initial). Our analysis shows that such irreversible changes in fracture permeability are consistent with either inelastic fracture shear dilation (where permeability increased) or inelastic fracture surface asperity shortening (where permeability decreased). These data are important for bounding model predictions of potential thermally-induced changes in rock-mass permeability at a future repository at Yucca Mountain.

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

2008-06-01T23:59:59.000Z

27

In-situ remediation of naturally occurring radioactive materials with high-permeability hydraulic fracturing  

E-Print Network [OSTI]

IN-SITU REMEDIATION OF NATURALLY OCCURRING RADIOACTIVE MATERIALS WITH HIGH-PERMEABILITY HYDRAULIC FRACTURING A Thesis by ANDRONIKOS STAVROS DEMARCHOS Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved as to style and content by: Michael J. Economides (Chair of Committee) ulat D. Mamora (Member...

Demarchos, Andronikos Stavros

1998-01-01T23:59:59.000Z

28

Oil recovery enhancement from fractured, low permeability reservoirs. Annual report 1990--1991, Part 1  

SciTech Connect (OSTI)

Joint funding by the Department of Energy and the State of Texas has Permitted a three year, multi-disciplinary investigation to enhance oil recovery from a dual porosity, fractured, low matrix permeability oil reservoir to be initiated. The Austin Chalk producing horizon trending thru the median of Texas has been identified as the candidate for analysis. Ultimate primary recovery of oil from the Austin Chalk is very low because of two major technological problems. The commercial oil producing rate is based on the wellbore encountering a significant number of natural fractures. The prediction of the location and frequency of natural fractures at any particular region in the subsurface is problematical at this time, unless extensive and expensive seismic work is conducted. A major portion of the oil remains in the low permeability matrix blocks after depletion because there are no methods currently available to the industry to mobilize this bypassed oil. The following multi-faceted study is aimed to develop new methods to increase oil and gas recovery from the Austin Chalk producing trend. These methods may involve new geological and geophysical interpretation methods, improved ways to study production decline curves or the application of a new enhanced oil recovery technique. The efforts for the second year may be summarized as one of coalescing the initial concepts developed during the initial phase to more in depth analyses. Accomplishments are predicting natural fractures; relating recovery to well-log signatures; development of the EOR imbibition process; mathematical modeling; and field test.

Poston, S.W.

1991-12-31T23:59:59.000Z

29

Natural and Induced Fracture Diagnostics from 4-D VSP Low Permeability Gas Reservoirs  

SciTech Connect (OSTI)

Tight gas sand reservoirs generally contain thick gas-charged intervals that often have low porosity and very low permeability. Natural and induced fractures provide the only means of production. The objective of this work is to locate and characterize natural and induced fractures from analysis of scattered waves recorded on 4-D (time lapse) VSP data in order to optimize well placement and well spacing in these gas reservoirs. Using model data simulating the scattering of seismic energy from hydraulic fractures, we first show that it is possible to characterize the quality of fracturing based upon the amount of scattering. In addition, the picked arrival times of recorded microseismic events provide the velocity moveout for isolating the scattered energy on the 4-D VSP data. This concept is applied to a field dataset from the Jonah Field in Wyoming to characterize the quality of the induced hydraulic fractures. The time lapse (4D) VSP data from this field are imaged using a migration algorithm that utilizes shot travel time tables derived from the first breaks of the 3D VSPs and receiver travel time tables based on the microseismic arrival times and a regional velocity model. Four azimuthally varying shot tables are derived from picks of the first breaks of over 200 VSP records. We create images of the fracture planes through two of the hydraulically fractured wells in the field. The scattered energy shows correlation with the locations of the microseismic events. In addition, the azimuthal scattering is different from the azimuthal reflectivity of the reservoir, giving us more confidence that we have separated the scattered signal from simple formation reflectivity. Variation of the scattered energy along the image planes suggests variability in the quality of the fractures in three distinct zones.

Mark E. Willis; Daniel R. Burns; M. Nafi Toksoz

2008-09-30T23:59:59.000Z

30

ABSTRACT: Upscaling Fracture Properties in Support of Dual-permeability Simulations  

SciTech Connect (OSTI)

Rainier Mesa (RM) is a tuffaceous, high-elevation plateau on the Nevada Test Site (NTS) that has been subjected to numerous nuclear tests between 1957 and 1992. Unlike other tests on the NTS located within or just above the saturated zone, tests at the RM T-tunnel complex were conducted within a variably saturated sequence of bedded and non-welded vitric and zeolitized tuff units, located approximately 500 m above the regional groundwater flow system. The low permeability and high porosity of the underlying zeolitized tuff units suggest the downward transport of radionuclides released from these tests are minimal through the tuff matrix. However, numerous faults observed to discharge water into tunnel drifts may serve as preferential pathways for radionuclide migration. Data collected from tunnel drifts indicate that faulting within the zeolitized tuff units is sparse with fractal clustering, and that connectivity between adjacent fault clusters is often weak to non-existent. The sparse fault density at RM, in conjunction with the extreme variability in the spatial distribution of faults, poses challenges not readily addressed by existing upscaling methods that upscale fracture properties as equivalent grid tensors. The unique fault statistics at RM has led to the development of a fracture continuum method designed to faithfully preserve flow and transport properties of the sparse fault networks. This method is based on selective mapping and upscaling of fault hydraulic and transport properties onto a continuum grid in support of dual-permeability simulations. Comparisons of global flow and random walk particle breakthrough between two-dimensional discrete fracture network and fracture continuum simulations demonstrate the utility of this method.

Rishi Parashar; Donald M. Reeves

2008-09-15T23:59:59.000Z

31

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 (OSTI)

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

32

Modelling of steady-state fluid flow in 3D fractured isotropic porous media: Application to effective permeability calculation  

E-Print Network [OSTI]

industrial applications such as: underground radioactive waste repositories, natural oil/gas recovery, geological CO2 storage, geothermal energy, etc. However, determining effective permeability for fractured and geotechnical engineers. Effective continuum is a simple and efficient approach to study the macroscopic

Paris-Sud XI, Université de

33

Numerical Modeling of Fracture Permeability Change in Naturally Fractured Reservoirs Using a Fully Coupled Displacement Discontinuity Method.  

E-Print Network [OSTI]

finite difference method to solve the fluid flow in fractures, a fully coupled displacement discontinuity method to build the global relation of fracture deformation, and the Barton-Bandis model of fracture deformation to build the local relation...

Tao, Qingfeng

2010-07-14T23:59:59.000Z

34

Permeability Estimation from Fracture Calibration Test Analysis in Shale and Tight Gas  

E-Print Network [OSTI]

closure can be used to estimate the reservoir permeability. However, for very low permeability, the time to reach radial flow can exceed any practical duration. This study shows how to use the reservoir pressure to estimate the maximum reservoir...

Xue, Han 1988-

2012-12-13T23:59:59.000Z

35

Property measurement and correlation for homogeneous and naturally fractured low permeability cores  

E-Print Network [OSTI]

This thesis presents the results of measurements from ten naturally fractured Devonian Shale cores using a new laboratory technique to determine the distinctive properties of the matrix and the fractures. The new technique is based on a pressure...

Fan, Jin

2012-06-07T23:59:59.000Z

36

Characterization of fracture reservoirs using static and dynamic data: From sonic and 3D seismic to permeability distribution. Annual report, March 1, 1996--February 28, 1997  

SciTech Connect (OSTI)

In low porosity, low permeability zones, natural fractures are the primary source of permeability which affect both production and injection of fluids. The open fractures do not contribute much to porosity, but they provide an increased drainage network to any porosity. They also may connect the borehole to remote zones of better reservoir characteristics. An important approach to characterizing the fracture orientation and fracture permeability of reservoir formations is one based on the effects of such conditions on the propagation of acoustic and seismic waves in the rock. The project is a study directed toward the evaluation of acoustic logging and 3D-seismic measurement techniques as well as fluid flow and transport methods for mapping permeability anisotropy and other petrophysical parameters for the understanding of the reservoir fracture systems and associated fluid dynamics. The principal application of these measurement techniques and methods is to identify and investigate the propagation characteristics of acoustic and seismic waves in the Twin Creek hydrocarbon reservoir owned by Union Pacific Resources (UPR) and to characterize the fracture permeability distribution using production data. This site is located in the overthrust area of Utah and Wyoming. UPR drilled six horizontal wells, and presently UPR has two rigs running with many established drill hole locations. In addition, there are numerous vertical wells that exist in the area as well as 3D seismic surveys. Each horizontal well contains full FMS logs and MWD logs, gamma logs, etc.

Parra, J.O.; Collier, H.A.; Owen, T.E. [and others

1997-06-01T23:59:59.000Z

37

Upscaling permeability for fractured concrete: meso-macro numerical approach coupled to strong discontinuities  

E-Print Network [OSTI]

- cations in Civil engineering such as geological CO2 storage or civil nuclear industry. In France, the latter aims at extending its nuclear powerplants lifetime which requires accurate quantifications of the outflow through the concrete vessel along different cases and accounting for the long-term evolution

38

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

39

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  

SciTech Connect (OSTI)

The primary objective is to measure and understand the variation of the fracture permeability of quartzite subjected to hydrothermal conditions. Pore fluids will consist of distilled water and aqueous Na/sub 2/CO/sub 3/ solutions at temperatures to 250/sup 0/C, fluid pressures to 20 MPa and effective normal stresses to 70 MPa. Fluid flow rates will be controllable to rates at least as small as 0.2 ml/day (approx. 4 fracture volumes). Experiments are designed to assess what role, if any, pressure solution may play at time scales of those of the experiments (less than or equal to 2 weeks). Secondary objectives are: (1) continue simulated fracture studies, incorporating inelastic deformation into model and characterize the nature of inelastic deformation occurring on loaded tensile fractures in quartzite; (2) continue dissolution experiment, with emphasis on dissolution modification of tensile fracture surfaces on quartzite; and (3) study natural fractures in a quartzite exhibiting hydrothermal dissolution features.

Not Available

1981-01-01T23:59:59.000Z

40

Liquid-Gas Relative Permeabilities in Fractures: Effects of Flow Structures, Phase Transformation and Surface  

E-Print Network [OSTI]

of geothermal, gas- condensate, and steam injection reservoirs. From this work, the main conclusions are: (1 which reflect the interactions among fluids and the rough fracture surface; (2) the steam-water flow Transformation and Surface Roughness Chih-Ying Chen June 2005 Financial support was provided through the Stanford

Stanford University

Note: This page contains sample records for the topic "outflow fracture permeability" 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

Characterization of fracture reservoirs using static and dynamic data: From sonic and 3D seismic to permeability distribution  

SciTech Connect (OSTI)

To characterize the Buena Vista Hills field, the authors have implemented methods of modeling, processing and interpretation. The modeling methods are based on deterministic and stochastic solutions. Deterministic solutions were developed in Phase 1 and applied in Phase 2 to simulate acoustic responses of laminated reservoirs. Specifically, the simulations were aimed at implementing processing techniques to correct P-wave and S-wave velocity logs for scattering effects caused by thin layering. The authors are also including a summary of the theory and the processing steps of this new method for predicting intrinsic dispersion and attenuation in Section 2. Since the objective for correcting velocity scattering effects is to predict intrinsic dispersion from velocity data, they are presenting an application to illustrate how to relate permeability anisotropy with intrinsic dispersion. Also, the theoretical solution for calculating full waveform dipole sonic that was developed in Phase 1 was applied to simulate dipole responses at different azimuthal source orientations. The results will be used to interpret the effects of anisotropy associated with the presence of vertical fractures at Buena Vista Hills. The results of the integration of core, well logs, and geology of Buena Vista Hills is also given in Section 2. The results of this integration will be considered as the input model for the inversion technique for processing production data. Section 3 summarizes accomplishments. In Section 4 the authors present a summary of the technology transfer and promotion efforts associated with this project. In the last section, they address the work to be done in the next six months and future work by applying the processing, modeling and inversion techniques developed in Phases 1 and 2 of this project.

Parra, J.O.; Hackett, C.L.; Brown, R.L.; Collier, H.A.; Datta-Gupta, A.

1998-10-01T23:59:59.000Z

42

Analytical and Numerical Solutions for the Case of a Horizontal Well with a Radial Power-Law Permeability Distribution--Comparison to the Multi-Fracture Horizontal Case  

E-Print Network [OSTI]

............................................................................ 26 3.9 Log-log plot of the analytical pD solutions at tD=105 for a horizontal well producing at a constant rate, centered in a radial composite reservoir with a power-law permeability distribution in the inner region... for numerical simulation (radial increment = 2 cm) ............................................ 40 4.2 Log-log plot of qD vs. tD for a PPR with rs = 75 ft and a MFH with xf = 75 ft and 10 md-ft fracture conductivity...

Broussard, Ryan Sawyer

2013-02-08T23:59:59.000Z

43

The effects of damage in and around a fracture upon the analysis of pressure data from low permeability gas wells  

E-Print Network [OSTI]

Buildup Data for a 100 Foot Fracture in an Unbounded Reservoir 15 16 Horner Plot of Pressure Buildup Data for a 100 Foot Fracture in an Unbounded Reservoir--Closure and non- Darcy Flow Included 17 Horner Plot of Pressure Buildup Data for a 100 Foot... Fracture in an Unbounded Reservoir--Closure and non- Darcy Flow Included--500 MCFPD Rate 18 10 Horner Plot of Pressure Buildup Data for a 100 Foot Fracture in an Unbounded Reservoir--Closure and non- Darcy Flow Included--1000 MCFPD Rate...

Fox, Thomas Lee

1980-01-01T23:59:59.000Z

44

In-situ stress and fracture permeability in a fault-hosted geothermal reservoir at Dixie Valley, Nevada  

SciTech Connect (OSTI)

As part of a study relating fractured rock hydrology to in-situ stress and recent deformation within the Dixie Valley Geothermal Field, borehole televiewer logging and hydraulic fracturing stress measurements were conducted in a 2.7-km-deep geothermal production well (73B-7) drilled into the Stillwater fault zone. Borehole televiewer logs from well 73B-7 show numerous drilling-induced tensile fractures, indicating that the direction of the minimum horizontal principal stress, S{sub hmin}, is S57{degrees}E. As the Stillwater fault at this location dips S50{degrees}E at {approximately}53{degrees}, it is nearly at the optimal orientation for normal faulting in the current stress field. Analysis of the hydraulic fracturing data shows that the magnitude of S{sub hmin} is 24.1 and 25.9 MPa at 1.7 and 2.5 km, respectively. In addition, analysis of a hydraulic fracturing test from a shallow well 1.5 km northeast of 73B-7 indicates that the magnitude of S{sub hmin} is 5.6 MPa at 0.4 km depth. Coulomb failure analysis shows that the magnitude of S{sub hmin} in these wells is close to that predicted for incipient normal faulting on the Stillwater and subparallel faults, using coefficients of friction of 0.6-1.0 and estimates of the in-situ fluid pressure and overburden stress. Spinner flowmeter and temperature logs were also acquired in well 73B-7 and were used to identify hydraulically conductive fractures.

Hickman, S. [Geological Survey, Menlo Park, CA (United States); Barton, C.; Zoback, M. [Stanford Univ., CA (United States)] [and others

1997-12-31T23:59:59.000Z

45

Simulation of fluid flow mechanisms in high permeability zones (Super-K) in a giant naturally fractured carbonate reservoir  

E-Print Network [OSTI]

and fractures were treated as two systems. Reservoir management practices and decisions should be very carefully reviewed and executed in this dual continuum reservoir based on the results of this work. Studying this dual media flow behavior is vital for better...

Abu-Hassoun, Amer H.

2009-05-15T23:59:59.000Z

46

METHOD DEVELOPMENT FOR DETERMINING THE HYDRAULIC CONDUCTIVITY OF FRACTURED POROUS MEDIA  

SciTech Connect (OSTI)

Plausible, but unvalidated, theoretical model constructs for unsaturated hydraulic conductivity of fractured porous media are currently used in Performance Assessment (PA) modeling for cracked saltstone and concrete (Flach 2011). The Nuclear Regulatory Commission (NRC) has expressed concern about the lack of model support for these assumed Moisture Characteristic Curves (MCC) data, as noted in Requests for Additional Information (RAIs) PA-8 and SP-4 (Savannah River Remediation, LLC, 2011). The objective of this task was to advance PA model support by developing an experimental method for determining the hydraulic conductivity of fractured cementitious materials under unsaturated conditions, and to demonstrate the technique on fractured saltstone samples. The task was requested through Task Technical Request (TTR) HLW-SSF-TTR-2012-0016 and conducted in accordance with Task Technical & Quality Assurance Plan (TTQAP) SRNL-TR-2012-00090. Preliminary method development previously conducted by Kohn et al. (2012) identified transient outflow extraction as the most promising method for characterizing the unsaturated properties of fractured porous media. While the research conducted by Kohn et al. (2012) focused on fractured media analogs such as stacked glass slides, the current task focused directly on fractured saltstone. For this task, four sample types with differing fracture geometries were considered: 1) intact saltstone, 2) intact saltstone with a single saw cut, smooth surface fracture, 3) micro-fractured saltstone (induced by oven drying), and 4) micro-fractured saltstone with a single, fully-penetrating, rough-surface fracture. Each sample type was tested initially for saturated hydraulic conductivity following method ASTM D 5084 using a flexible wall permeameter. Samples were subsequently tested using the transient outflow extraction method to determine cumulative outflow as a function of time and applied pressure. Of the four sample types tested, two yielded datasets suitable for analysis (sample types 3 and 4). The intact saltstone sample (sample type 1) did not yield any measureable outflow over the pressure range of the outflow test (0-1000 cm H{sub 2}O). This was expected because the estimated air entry pressure for intact saltstone is on the order of 100,000 cm H{sub 2}O (Dixon et al., 2009). The intact saltstone sample with a single saw cut smooth surface fracture (sample type 2) did not produce useable data because the fracture completely drained at less than 10 cm H{sub 2}O applied pressure. The cumulative outflow data from sample types 3 and 4 were analyzed using an inverse solution of the Richard’s equation for water flow in variably saturated porous media. This technique was implemented using the computer code Hydrus-1D (Šim?nek et al., 2008) and the resulting output included the van Genuchten-Mualem water retention and relative permeability parameters and predicted saturated hydraulic conductivity (Van Genuchten, 1980; Van Genuchten et al., 1991). Estimations of relative permeability and saturated conductivity are possible because the transient response of the sample to pressure changes is recorded during the multi-step outflow extraction test. Characteristic curves were developed for sample types 3 and 4 based on the results of the transient outflow method and compared to that of intact saltstone previously reported by Dixon et al. (2009). The overall results of this study indicate that the outflow extraction method is suitable for measuring the hydraulic properties of micro-fractured porous media. The resulting cumulative outflow data can be analyzed using the computer code Hydrus-1D to generate the van Genuchten curve fitting parameters that adequately describe fracture drainage. The resulting characteristic curves are consistent with blended characteristic curves that combine the behaviors of low pressure drainage associated with fracture flow with high pressure drainage from the bulk saltstone matrix.

Dixon, K.

2013-09-30T23:59:59.000Z

47

Fracture characterization from attenuation of Stoneley waves across a fracture  

E-Print Network [OSTI]

Fractures contribute significantly to the permeability of a formation. It is important to understand the fracture distribution and fluid transmissivity. Though traditional well logs can image fractures intersecting the ...

Bakku, Sudhish Kumar

2012-01-01T23:59:59.000Z

48

Poroelastic modeling of seismic boundary conditions across a fracture  

E-Print Network [OSTI]

on poroelasticity of fractures. Both authors would like toYork. Figure 3: For a high permeability fracture, the fluidpressure across the fracture is continuous, which can be

Schoenberg, M.A.; Nakagawa, S.

2006-01-01T23:59:59.000Z

49

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...

Lolon, Elyezer P.

2006-04-12T23:59:59.000Z

50

The Role of Geochemistry and Stress on Fracture Development and Proppant Behavior in EGS Reservoirs  

Broader source: Energy.gov [DOE]

Project objective: Develop Improved Methods For Maintaining Permeable Fracture Volumes In EGS Reservoirs.

51

Interaction between Injection Points during Hydraulic Fracturing Kjetil M. D. Hals1,  

E-Print Network [OSTI]

fluid to create fracture networks in rock layers with low permeabilities. A fracking fluid is injected

Santos, Juan

52

Poroelastic modeling of seismic boundary conditions across a fracture  

E-Print Network [OSTI]

Permeability of a fracture can affect how the fracture interacts with seismic waves. ... characteristic parameters that control the seismic response of single ...

2007-07-20T23:59:59.000Z

53

Method for directional hydraulic fracturing  

DOE Patents [OSTI]

A method for directional hydraulic fracturing using borehole seals to confine pressurized fluid in planar permeable regions, comprising: placing a sealant in the hole of a structure selected from geologic or cemented formations to fill the space between a permeable planar component and the geologic or cemented formation in the vicinity of the permeable planar component; making a hydraulic connection between the permeable planar component and a pump; permitting the sealant to cure and thereby provide both mechanical and hydraulic confinement to the permeable planar component; and pumping a fluid from the pump into the permeable planar component to internally pressurize the permeable planar component to initiate a fracture in the formation, the fracture being disposed in the same orientation as the permeable planar component.

Swanson, David E. (West St. Paul, MN); Daly, Daniel W. (Crystal, MN)

1994-01-01T23:59:59.000Z

54

Geothermal Permeability Enhancement - Final Report  

SciTech Connect (OSTI)

The overall objective is to apply known permeability enhancement techniques to reduce the number of wells needed and demonstrate the applicability of the techniques to other undeveloped or under-developed fields. The Enhanced Geothermal System (EGS) concept presented in this project enhances energy extraction from reduced permeability zones in the super-heated, vapor-dominated Aidlin Field of the The Geysers geothermal reservoir. Numerous geothermal reservoirs worldwide, over a wide temperature range, contain zones of low permeability which limit the development potential and the efficient recovery of heat from these reservoirs. Low permeability results from poorly connected fractures or the lack of fractures. The Enhanced Geothermal System concept presented here expands these technologies by applying and evaluating them in a systematic, integrated program.

Joe Beall; Mark Walters

2009-06-30T23:59:59.000Z

55

Regional Analysis And Characterization Of Fractured Aquifers...  

Open Energy Info (EERE)

geothermal applications include the recognition of and exploration for deep fracture permeability in crystalline rocks. It is well known that the best currently available...

56

Fracture opening/propagation behavior and their significance on pressure-time records during hydraulic fracturing  

SciTech Connect (OSTI)

Hydraulic fracturing with constant fluid injection rate was numerically modeled for a pair of rectangular longitudinal fractures intersecting a wellbore in an impermeable rock mass, and numerical calculations have been performed to investigate the relations among the form of pressure-time curves, fracture opening/propagation behavior and permeability of the mechanically closed fractures. The results have shown that both permeability of the fractures and fluid injection rate significantly influence the form of the pressure-time relations on the early stage of fracture opening. Furthermore it has been shown that wellbore pressure during fracture propagation is affected by the pre-existing fracture length.

Takashi Kojima; Yasuhiko Nakagawa; Koji Matsuki; Toshiyuki Hashida

1992-01-01T23:59:59.000Z

57

Hydrocarbon anomaly in soil gas as near-surface expressions of upflows and outflows in geothermal systems  

SciTech Connect (OSTI)

A variety of hydrocarbons, C1 - C12, have been found in volcanic gases (fumarolic) and in geothermal waters and gases. The hydrocarbons are thought to have come from products of pyrolysis of kerogen in sedimentary rocks or they could be fed into the geothermal system by the recharging waters which may contain dissolved hydrocarbons or hydrocarbons extracted by the waters from the rocks. In the hot geothermal zone, 300°+ C, many of these hydrocarbons are in their critical state. It is thought that they move upwards due to buoyancy and flux up with the upflowing geothermal fluids in the upflow zones together with the magmatic gases. Permeability which could be provided by faults, fissures, mini and micro fractures are thought to provide pathways for the upward flux. A sensitive technique (Petrex) utilizing passive integrative adsorption of the hydrocarbons in soil gas on activated charcoal followed by desorption and analysis of the hydrocarbons by direct introduction mass spectrometry allows mapping of the anomalous areas. Surveys for geothermal resources conducted in Japan and in Indonesia show that the hydrocarbon anomaly occur over known fields and over areas strongly suspected of geothermal potential. The hydrocarbons found and identified were n-paraffins (C7-C9) and aromatics (C7-C8). Detection of permeable, i.e. active or open faults, parts of older faults which have been reactivated, e.g. by younger intersecting faults, and the area surrounding these faulted and permeable region is possible. The mechanism leading to the appearance of the hydrocarbon in the soil gas over upflow zones of the geothermal reservoir is proposed. The paraffins seems to be better pathfinders for the location of upflows than the aromatics. However the aromatics may, under certain circumstances, give better indications of the direction of the outflow of the geothermal system. It is thought that an upflow zone can be defined when conditions exist where the recharging waters containing the hydrocarbons feed into the geothermal kitchen. The existence of open and active faults, fissures, mini and micro fractures allow sufficient permeability for the gases to flux up and express themselves at the surface as hydrocarbon anomaly in the soil gas. When any of the requirements is absent, i.e. in the absence of the recharging waters, hydrocarbons, temperature, or permeability, no anomaly can be expected. It assumes a dynamic convective system, i.e. recharging waters, upflow and outflow. The anomalies however can define to a certain extent, regions of geothermal upflow, buoyant transport of gases, and frequently down-gradient of cooling waters.

Ong, H.L.; Higashihara, M.; Klusman, R.W.; Voorhees, K.J.; Pudjianto, R.; Ong, J

1996-01-24T23:59:59.000Z

58

Surfactant-enhanced spontaneous imbibition process in highly fractured carbonate reservoirs.  

E-Print Network [OSTI]

??Highly fractured carbonate reservoirs are a class of reservoirs characterized by high conductivity fractures surrounding low permeability matrix blocks. In these reservoirs, wettability alteration is… (more)

Chen, Peila

2011-01-01T23:59:59.000Z

59

Evidence of Pressure Dependent Permeability in Long-Term Shale Gas Production and Pressure Transient Responses  

E-Print Network [OSTI]

The current state of shale gas reservoir dynamics demands understanding long-term production, and existing models that address important parameters like fracture half-length, permeability, and stimulated shale volume assume constant permeability...

Vera Rosales, Fabian 1986-

2012-12-11T23:59:59.000Z

60

E-Print Network 3.0 - arterioso permeable por Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

difference... of two media, matrix and fractures. The matrix system is relatively tight with insignificant permeability Source: Schechter, David S. - Department of Petroleum...

Note: This page contains sample records for the topic "outflow fracture permeability" 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

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...

Lee, Byungtark

2011-10-21T23:59:59.000Z

62

Characterizing Fractures in the Geysers Geothermal Field by Micro...  

Broader source: Energy.gov (indexed) [DOE]

if fracturing could be used to enhance permeability; and whether dilution of existing fluids with injected water would lower corrosivity enough to allow economic production of...

63

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...

Kumar, Amrendra

2009-05-15T23:59:59.000Z

64

Hydraulic Fracture Monitoring: A Jonah Field Case Study  

E-Print Network [OSTI]

Hydraulic fracturing involves the injection of a fluid to fracture oil and gas reservoirs, and thus increase their permeability. The process creates numerous microseismic events, which can be used to monitor subsurface ...

Seher, T.

2011-01-01T23:59:59.000Z

65

Evaluating Permeability Enchancement Using Electrical Techniques  

SciTech Connect (OSTI)

Enhanced Geothermal Systems (EGS) development projects involve the artificial stimulation of relatively impermeable high-temperature underground regions (at depths of 2-4 kilometers or more) to create sufficient permeability to permit underground fluid circulation, so that hot water can be withdrawn from production wells and used to generate electric power. Several major research projects of this general type have been undertaken in the past in New Mexico (Fenton Hill), Europe, Japan and Australia. Recent U.S. activities along these lines focus mainly on stimulating peripheral areas of existing operating hydrothermal fields rather than on fresh 'greenfield' sites, but the long-term objective of the Department of Energy's EGS program is the development of large-scale power projects based on EGS technology (MIT, 2006; NREL, 2008). Usually, stimulation is accomplished by injecting water into a well at high pressure, enhancing permeability by the creation and propagation of fractures in the surrounding rock (a process known as 'hydrofracturing'). Beyond just a motivation, low initial system permeability is also an essential prerequisite to hydrofracturing. If the formation permeability is too high, excessive fluid losses will preclude the buildup of sufficient pressure to fracture rock. In practical situations, the actual result of injection is frequently to re-open pre-existing hydrothermally-mineralized fractures, rather than to create completely new fractures by rupturing intact rock. Pre-existing fractures can often be opened using injection pressures in the range 5-20 MPa. Creation of completely new fractures will usually require pressures that are several times higher. It is preferable to undertake development projects of this type in regions where tectonic conditions are conducive to shear failure, so that when pre-existing fractures are pressurized they will fail by shearing laterally. If this happens, the fracture will often stay open afterwards even if injection subsequently ceases. The principal barrier to EGS utilization for electricity generation is project economics. Costs for geothermal electricity obtained from conventional hydrothermal systems are just marginally competitive. Unless and until the costs of routinely and reliably creating and exploiting artificial subterranean fracture networks that can deliver useful quantities of hot fluid to production wells for long periods of time (years) are reduced to levels comparable to those of a conventional geothermal development project, EGS will be of little interest to the electrical power industry. A significant obstacle to progress in projects of this general type is the difficulty of appraising the properties (geometry, fluid transmissivity, etc.) of the fracture(s) created/re-opened by injection. Sustainability of power production is critically dependent upon reservoir thermal sweep efficiency, which depends in turn on the geometry of the fracture network and its interconnections with the various production and injection wells used to circulate fluid underground. If no permeable connections are created between the wells, fluid flow will be too slow for practical utility. If the connections are too good, however (such as a production/injection well pair connected by a single very permeable fracture), production wellhead temperatures will decline rapidly. Unless the permeable fractures created by hydrofracturing can be accurately mapped, the cost of subsequent trial-and-error drilling to try to establish a suitable fluid circulation system is likely to dominate project economics and render EGS impractical.

John W. Pritchett

2008-09-01T23:59:59.000Z

66

Department of Earth Sciences www.rhul.ac.uk/earthsciences Page 1 of 2 New methods for maximising shale permeability and minimising risk  

E-Print Network [OSTI]

shale permeability and minimising risk during hydraulic fracturing Supervisor(s): Agust Gudmundsson-fracture mechanics, rock physics, and sedimentology there are three aspects of hydraulic fracturing of gas shales. More specifically, hydraulic fracturing of gas shales requires that fluid-driven fractures propagate

Sheldon, Nathan D.

67

Estimation of Fracture Porosity in an Unsaturated Fractured Welded Tuff Using Gas Tracer Testing  

SciTech Connect (OSTI)

Kinematic fracture porosity is an important hydrologic transport parameter for predicting the potential of rapid contaminant migration through fractured rock. The transport velocity of a solute moving within a fracture network is inversely related to the fracture porosity. Since fracture porosity is often one or two orders of magnitude smaller than matrix porosity, and fracture permeability is often orders of magnitude greater than matrix permeability, solutes may travel significantly faster in the fracture network than in the surrounding matrix. This dissertation introduces a new methodology for conducting gas tracer tests using a field portable mass spectrometer along with analytical tools for estimating fracture porosity using the measured tracer concentration breakthrough curves. Field experiments were conducted at Yucca Mountain, Nevada, consisting of air-permeability transient testing and gas-tracer-transport tests. The experiments were conducted from boreholes drilled within an underground tunnel as part of an investigation of rock mass hydrological behavior. Air-permeability pressure transients, recorded during constant mass flux injections, have been analyzed using a numerical inversion procedure to identify fracture permeability and porosity. Dipole gas tracer tests have also been conducted from the same boreholes used for air-permeability testing. Mass breakthrough data has been analyzed using a random walk particle-tracking model, with a dispersivity that is a function of the advective velocity. The estimated fracture porosity using the tracer test and air-injection test data ranges from .001 to .015. These values are an order of magnitude greater than the values estimated by others using hydraulically estimated fracture apertures. The estimates of porosity made using air-permeability test data are shown to be highly sensitive to formation heterogeneity. Uncertainty analyses performed on the gas tracer test results show high confidence in the parameter estimates made.

B.M. Freifeild

2001-10-18T23:59:59.000Z

68

Characterization of natural fractures in Mesaverde core from the multiwell experiment  

SciTech Connect (OSTI)

Natural fractures dominate the permeability of tight sandstone reservoirs in the Mesaverde Formation of the Piceance Creek Basin, north-western Colorado. Roughly 1900 natural fractures, detected in 4200 ft of Mesaverde core from the US Department of Energy's Multiwell Experiment (MWX), have been differentiated into 10 different fracture types on the basis of fracture morphology, inclination, the presence of slickensides, the presence of dickite mineralization and/or host lithology. Approximately 75% of the MWX core fractures are dewatering planes in mudstone and are probably unimportant to reservoir permeability. The remaining 25% of the MWX core fractures include 275 mostly calcite-mineralized, vertical extension fractures, 61 irregular, dickite-mineralized extension fractures, 27 mostly calcite-mineralized, horizontal extension fractures, and 90 slickensided, occasionally mineralized shear fractures. These extension and shear fractures are all potentially important to reservoir permeability and consequently productivity. 13 refs., 61 figs., 2 tabs.

Finley, S.J.; Lorenz, J.C.

1988-09-01T23:59:59.000Z

69

A Triple-Porosity Model for Fractured Horizontal Wells  

E-Print Network [OSTI]

. The model consists of three contiguous porous media: the matrix, less permeable micro-fractures and more permeable macro-fractures. Only the macro-fractures produce to the well while they are fed by the micro-fractures only. Consequently, the matrix feeds... the micro-fractures only. Therefore, the flow is sequential from one medium to the other. Four sub-models are derived based on the interporosity flow assumption between adjacent media, i.e., pseudosteady state or transient flow assumption. These are fully...

Alahmadi, Hasan Ali H.

2010-10-12T23:59:59.000Z

70

Estimating Major and Minor Natural Fracture Patterns in Gas  

E-Print Network [OSTI]

Estimating Major and Minor Natural Fracture Patterns in Gas Shales Using Production Data Razi Identification of infill drilling locations has been challenging with mixed results in gas shales. Natural fractures are the main source of permeability in gas shales. Natural fracture patterns in shale has a random

Mohaghegh, Shahab

71

Experimental Investigation of Propped Fracture Conductivity in Tight Gas Reservoirs Using The Dynamic Conductivity Test.  

E-Print Network [OSTI]

??Hydraulic Fracturing stimulation technology is used to increase the amount of oil and gas produced from low permeability reservoirs. The primary objective of the process… (more)

Romero Lugo, Jose 1985-

2012-01-01T23:59:59.000Z

72

Protostellar outflow-driven turbulence  

E-Print Network [OSTI]

Protostellar outflows crisscross the regions of star cluster formation, stirring turbulence and altering the evolution of the forming cluster. We model the stirring of turbulent motions by protostellar outflows, building on an observation that the scaling law of supersonic turbulence implies a momentum cascade analogous to the energy cascade in Kolmogorov turbulence. We then generalize this model to account for a diversity of outflow strengths, and for outflow collimation, both of which enhance turbulence. For a single value of its coupling coefficient the model is consistent with turbulence simulations by Li & Nakamura and, plausibly, with observations of the NGC 1333 cluster-forming region. Outflow-driven turbulence is strong enough to stall collapse in cluster-forming regions for several crossing times, relieving the mismatch between star formation and turbulent decay rates. The predicted line-width-size scaling implies radial density indices between -1 and -2 for regions supported by outflow-driven turbulence, with a tendency for steeper profiles in regions that are more massive or have higher column densities.

Christopher D. Matzner

2007-01-01T23:59:59.000Z

73

FRACTURING FLUID CHARACTERIZATION FACILITY  

SciTech Connect (OSTI)

Hydraulic fracturing technology has been successfully applied for well stimulation of low and high permeability reservoirs for numerous years. Treatment optimization and improved economics have always been the key to the success and it is more so when the reservoirs under consideration are marginal. Fluids are widely used for the stimulation of wells. The Fracturing Fluid Characterization Facility (FFCF) has been established to provide the accurate prediction of the behavior of complex fracturing fluids under downhole conditions. The primary focus of the facility is to provide valuable insight into the various mechanisms that govern the flow of fracturing fluids and slurries through hydraulically created fractures. During the time between September 30, 1992, and March 31, 2000, the research efforts were devoted to the areas of fluid rheology, proppant transport, proppant flowback, dynamic fluid loss, perforation pressure losses, and frictional pressure losses. In this regard, a unique above-the-ground fracture simulator was designed and constructed at the FFCF, labeled ''The High Pressure Simulator'' (HPS). The FFCF is now available to industry for characterizing and understanding the behavior of complex fluid systems. To better reflect and encompass the broad spectrum of the petroleum industry, the FFCF now operates under a new name of ''The Well Construction Technology Center'' (WCTC). This report documents the summary of the activities performed during 1992-2000 at the FFCF.

Subhash Shah

2000-08-01T23:59:59.000Z

74

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...

Kamenov, Anton

2013-04-11T23:59:59.000Z

75

Fracture Blisters  

E-Print Network [OSTI]

21. McCann S, Gruen G. Fracture Blisters: A Review of thewith Lower Extremity Fracture: Results of a ProspectiveC, Koval K. Treatment of Fracture Blisters: A Prospective

Uebbing, Claire M; Walsh, Mark; Miller, Joseph B; Abraham, Mathew; Arnold, Clifford

2011-01-01T23:59:59.000Z

76

2006 GeoX Conference, pages 1 to 6 Characterisation of hydraulic fractures in  

E-Print Network [OSTI]

2006 GeoX Conference, pages 1 to 6 Characterisation of hydraulic fractures in limestones using X, France Jacques.Desrues@hmg.inpg.fr ABSTRACT: Hydraulic tension fractures were produced in porous, hydraulic fracture, permeability tensor MOTS-CLÃ?S: microtomographie, fracturation hydraulique, tenseur de

77

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

SciTech Connect (OSTI)

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

78

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

79

Laboratory measurement of water imbibition into low-permeability welded tuff  

E-Print Network [OSTI]

repository. As water infiltrates down from the ground surface through the fracture network, some water mayLaboratory measurement of water imbibition into low-permeability welded tuff M.Q. Hu*, P. Persoff accurately water imbibi- tion and vapor condensation into welded tuff of low permeability. Automatically

Hu, Qinhong "Max"

80

Characterizing Fractures in the Geysers Geothermal Field by Micro-seismic Data, Using Soft Computing, Fractals, and Shear Wave Anisotropy  

Broader source: Energy.gov [DOE]

Determine if fracturing could be used to enhance permeability; and whether dilution of existing fluids with injected water would lower corrosivity enough to allow economic production of power.

Note: This page contains sample records for the topic "outflow fracture permeability" 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

Optimization of fractured well performance of horizontal gas wells  

E-Print Network [OSTI]

In low-permeability gas reservoirs, horizontal wells have been used to increase the reservoir contact area, and hydraulic fracturing has been further extending the contact between wellbores and reservoirs. This thesis presents an approach...

Magalhaes, Fellipe Vieira

2009-06-02T23:59:59.000Z

82

Geomechanical Development of Fractured Reservoirs During Gas Production  

E-Print Network [OSTI]

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...

Huang, Jian

2013-04-05T23:59:59.000Z

83

A Study of Hydraulic Fracturing Initiation in Transversely Isotropic Rocks  

E-Print Network [OSTI]

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

2011-10-21T23:59:59.000Z

84

FRACTURED PETROLEUM RESERVOIRS  

SciTech Connect (OSTI)

The four chapters that are described in this report cover a variety of subjects that not only give insight into the understanding of multiphase flow in fractured porous media, but they provide also major contribution towards the understanding of flow processes with in-situ phase formation. In the following, a summary of all the chapters will be provided. Chapter I addresses issues related to water injection in water-wet fractured porous media. There are two parts in this chapter. Part I covers extensive set of measurements for water injection in water-wet fractured porous media. Both single matrix block and multiple matrix blocks tests are covered. There are two major findings from these experiments: (1) co-current imbibition can be more efficient than counter-current imbibition due to lower residual oil saturation and higher oil mobility, and (2) tight fractured porous media can be more efficient than a permeable porous media when subjected to water injection. These findings are directly related to the type of tests one can perform in the laboratory and to decide on the fate of water injection in fractured reservoirs. Part II of Chapter I presents modeling of water injection in water-wet fractured media by modifying the Buckley-Leverett Theory. A major element of the new model is the multiplication of the transfer flux by the fractured saturation with a power of 1/2. This simple model can account for both co-current and counter-current imbibition and computationally it is very efficient. It can be orders of magnitude faster than a conventional dual-porosity model. Part II also presents the results of water injection tests in very tight rocks of some 0.01 md permeability. Oil recovery from water imbibition tests from such at tight rock can be as high as 25 percent. Chapter II discusses solution gas-drive for cold production from heavy-oil reservoirs. The impetus for this work is the study of new gas phase formation from in-situ process which can be significantly different from that of gas displacement processes. The work is of experimental nature and clarifies several misconceptions in the literature. Based on experimental results, it is established that the main reason for high efficiency of solution gas drive from heavy oil reservoirs is due to low gas mobility. Chapter III presents the concept of the alteration of porous media wettability from liquid-wetting to intermediate gas-wetting. The idea is novel and has not been introduced in the petroleum literature before. There are significant implications from such as proposal. The most direct application of intermediate gas wetting is wettability alteration around the wellbore. Such an alteration can significantly improve well deliverability in gas condensate reservoirs where gas well deliverability decreases below dewpoint pressure. Part I of Chapter III studies the effect of gravity, viscous forces, interfacial tension, and wettability on the critical condensate saturation and relative permeability of gas condensate systems. A simple phenomenological network model is used for this study, The theoretical results reveal that wettability significantly affects both the critical gas saturation and gas relative permeability. Gas relative permeability may increase ten times as contact angle is altered from 0{sup o} (strongly liquid wet) to 85{sup o} (intermediate gas-wetting). The results from the theoretical study motivated the experimental investigation described in Part II. In Part II we demonstrate that the wettability of porous media can be altered from liquid-wetting to gas-wetting. This part describes our attempt to find appropriate chemicals for wettability alteration of various substrates including rock matrix. Chapter IV provides a comprehensive treatment of molecular, pressure, and thermal diffusion and convection in porous media Basic theoretical analysis is presented using irreversible thermodynamics.

Abbas Firoozabadi

1999-06-11T23:59:59.000Z

85

Studies of Transport Properties of Fractures: Final Report  

SciTech Connect (OSTI)

We proposed to study several key factors controlling the character and evolution of fracture system permeability and transport processes. We suggest that due to surface roughness and the consequent channeling in single fractures and in fracture intersections, the tendency of a fracture system to plug up, remain permeable, or for permeability to increase due to chemical dissolution/precipitation conditions will depend strongly on the instantaneous flow channel geometry. This geometry will change as chemical interaction occurs, thus changing the permeability through time. To test this hypothesis and advance further understanding toward a predictive capability, we endeavored to physically model and analyze several configurations of flow and transport of inert and chemically active fluids through channels in single fractures and through fracture intersections. This was an integrated program utilizing quantitative observations of fractures and veins in drill core, quantitative and visual observations of flow and chemical dissolution and precipitation within replicas of real rough-walled fractures and fracture intersections, and numerical modeling via lattice Boltzmann methods.

Stephen R. Brown

2006-06-30T23:59:59.000Z

86

Factors that affect fracture fluid clean-up and pressure buildup test results in tight gas reservoirs  

E-Print Network [OSTI]

engineering effort with a complete formation evaluation prior to the stimulation treatment can one understand a well containing a vertical hydraulic fracture. If the reservoir produces substantial volumes of either fracture fluid or formation water, along... and Water Permeability . . . 21 Fracture Relative Gas and Water Permeability . . . . . . 24 Created and Propped Fracture Lengths as a Function of Treatment Volume Based on FRACDIM ZI One Quarter of a Square Pattern with Wellbore Centered in Middle...

Montgomery, Kevin Todd

1990-01-01T23:59:59.000Z

87

Gas condensate damage in hydraulically fractured wells  

E-Print Network [OSTI]

), md 0.15 Porosity (g102), fraction 0.1 Water Saturation (S w ), fraction 0.16 Initial Pressure (p i ), psi 3,900 Injection Pressure (p inj ), psi 3,910 Dewpoint Pressure (p d ), psi 3,500 Temperature (T), o F 200 Total Compressibility (c g... simulation ..........................13 3.4 Permeability reduction normal to fracture face .........................................14 3.5 Quarter model for 80 acre drainage area....................................................15 3.6 Fracture face...

Adeyeye, Adedeji Ayoola

2004-09-30T23:59:59.000Z

88

Permeability of WIPP Salt During Damage Evolution and Healing  

SciTech Connect (OSTI)

The presence of damage in the form of microcracks can increase the permeability of salt. In this paper, an analytical formulation of the permeability of damaged rock salt is presented for both initially intact and porous conditions. The analysis shows that permeability is related to the connected (i.e., gas accessible) volumetric strain and porosity according to two different power-laws, which may be summed to give the overall behavior of a porous salt with damage. This relationship was incorporated into a constitutive model, known as the Multimechanism Deformation Coupled Fracture (MDCF) model, which has been formulated to describe the inelastic flow behavior of rock salt due to coupled creep, damage, and healing. The extended model was used to calculate the permeability of rock salt from the Waste Isolation Pilot Plant (WIPP) site under conditions where damage evolved with stress over a time period. Permeability changes resulting from both damage development under deviatoric stresses and damage healing under hydrostatic pressures were considered. The calculated results were compared against experimental data from the literature, which indicated that permeability in damaged intact WIPP salt depends on the magnitude of the gas accessible volumetric strain and not on the total volumetric strain. Consequently, the permeability of WIPP salt is significantly affected by the kinetics of crack closure, but shows little dependence on the kinetics of crack removal by sintering.

BODNER,SOL R.; CHAN,KWAI S.; MUNSON,DARRELL E.

1999-12-03T23:59:59.000Z

89

Flow focusing in unsaturated fracture networks: A numerical investigation  

SciTech Connect (OSTI)

A numerical modeling study is presented to investigate flow-focusing phenomena in a large-scale fracture network, constructed using field data collected from the unsaturated zone of Yucca Mountain, Nevada, the proposed repository site for high-level nuclear waste. The two-dimensional fracture network for an area of 100 m x 150 m contains more than 20,000 fractures. Steady-state unsaturated flow in the fracture network is investigated for different boundary conditions and rock properties. Simulation results indicate that flow paths are generally vertical, and that horizontal fractures mainly provide pathways between neighboring vertical paths. In addition to fracture properties, flow-focusing phenomena are also affected by rock-matrix permeability, with lower matrix permeability leading to a high degree of flow focusing. The simulation results further indicate that the average spacing between flow paths in a layered system tends to increase and flow tends to becomes more focused, with depth.

Zhang, Keni; Wu, Yu-Shu; Bodvarsson, G.S.; Liu, Hui-Hai

2003-04-17T23:59:59.000Z

90

Poroelastic modeling of fracture-seismic wave interaction  

SciTech Connect (OSTI)

Rock containing a compliant, fluid-filled fracture can be viewed as one case of heterogeneous poroelastic media. When this fracture is subjected to seismic waves, a strong contrast in the elastic stiffness between the fracture itself and the background can result in enhanced grain-scale local fluid flow. Because this flow--relaxing the pressure building up within the fracture--can increase the dynamic compliance of the fracture and change energy dissipation (attenuation), the scattering of seismic waves can be enhanced. Previously, for a flat, infinite fracture, we derived poroelastic seismic boundary conditions that describe the relationship between a finite jump in the stress and displacement across a fracture, expressed as a function of the stress and displacement at the boundaries. In this paper, we use these boundary conditions to determine frequency-dependent seismic wave transmission and reflection coefficients. Fluid-filled fractures with a range of mechanical and hydraulic properties are examined. From parametric studies, we found that the hydraulic permeability of a fracture fully saturated with water has little impact on seismic wave scattering. In contrast, the seismic response of a partially water-saturated fracture and a heterogeneous fracture filled with compliant liquid (e.g., supercritical CO{sub 2}) depended on the fracture permeability.

Nakagawa, Seiji

2008-08-15T23:59:59.000Z

91

On Damage Propagation in a Soft Low-Permeability Formation  

SciTech Connect (OSTI)

In this presentation, we develop a mathematical model of fluid flow with changing formation properties. The modification of formation permeability is caused by development of a connected system of fractures. As the fluids are injected or withdrawn from the reservoir, the balance between the pore pressure and the geostatic formation stresses is destroyed. If the strength of the rock is not sufficient to accommodate such an imbalance, the cementing bonds between the rock grains become broken. Such a process is called damage propagation. The micromechanics and the basic mathematical model of damage propagation have been studied in [7]. The theory was further developed in [3], where new nonlocal damage propagation model has been studied. In [2] this theory has been enhanced by incorporation of the coupling between damage propagation and fluid flow. As it has been described above, the forced fluid flow causes changes in the rock properties including formation permeability. At the same time, changing permeability facilitates fluid flow and, therefore, enhances damage propagation. One of the principle concepts introduced in [3] and [2] is the characterization of damage by a dimensionless ratio of the number of broken bonds to the number of bonds in pristine rock per unit volume. It turns out, that the resulting mathematical model consist of a system of two nonlinear parabolic equations. As it has been shown in [6] using modeling of micromechanical properties of sedimentary rocks, at increasing stress the broken bonds coalesce into a system of cracks surrounding practically intact matrix blocks. These blocks have some characteristic size and a regular geometry. The initial microcracks expand, interact with each other, coalesce and form bigger fractures, etc. Therefore, as the damage is accumulated, the growing system of connected fractures determines the permeability of the reservoir rock. Significant oil deposits are stored in low-permeability soft rock reservoirs such as shales, chalks and diatomites [9, 10]. The permeability of the pristine formation matrix in such reservoirs is so low that oil production was impossible until hydraulic fracturing was applied. For development of correct production policy, it is very significant to adequately understand and predict how fast and to what extend the initial damage induced by drilling and hydrofracturing will propagate into the reservoir. The importance of fractures for rock flow properties is a well-established and recognized fact [4, 9, 5]. Different conceptual models have been developed [8]. In this study, we propose a damage propagation model based on a combination of the model of double-porosity and double-permeability medium [4] and a modification of the model of damage propagation developed in [2].

Silin, D.; Patzek, T.; Barenblatt, G.I.

2003-11-18T23:59:59.000Z

92

Hydraulic Fracturing (Vermont)  

Broader source: Energy.gov [DOE]

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

93

Enthalpy transients in fractured two-phase geothermal systems  

SciTech Connect (OSTI)

Numerical modeling techniques are used to study the changes in flowing enthalpy of fluids produced from a well completed in a fractured two-phase geothermal reservoir. Complex interactions between different fracture and porous matrix parameters control the enthalpy transients. The results show that the flowing enthalpy is most sensitive to the characteristics of the relative permeability curves, the magnitude of the matrix permeability and the effective fracture porosity. Other parameters such as the thermal conductivity and fracture spacing also significantly affect the flowing enthalpy. In spite of the complex phenomena associated with enthalpy transients in fractured two-phase systems, it is possible to infer useful information about the producing geothermal reservoirs from field data. 15 refs., 13 figs., 2 tabs.

Lippmann, M.J.; Bodvarsson, G.S.; Gaulke, S.W.

1985-03-01T23:59:59.000Z

94

Laboratory investigation of crushed salt consolidation and fracture healing  

SciTech Connect (OSTI)

A laboratory test program was conducted to investigate the consolidation behavior of crushed salt and fracture healing in natural and artificial salt. Crushed salt is proposed for use as backfill in a nuclear waste repository in salt. Artificial block salt is proposed for use in sealing a repository. Four consolidation tests were conducted in a hydrostatic pressure vessel at a maximum pressure of 2500 psi (17.2 MPa) and at room temperature. Three 1-month tests were conducted on salt obtained from the Waste Isolation Pilot Plant and one 2-month test was conducted on salt from Avery Island. Permeability was obtained using argon and either a steady-state or transient method. Initial porosities ranged from 0.26 to 0.36 and initial permeabilities from 2000 to 50,000 md. Final porosities and permeabilities ranged from 0.05 to 0.19 and from <10/sup -5/ md to 110 md, respectively. The lowest final porosity (0.05) and permeability (<10/sup -5/ md) were obtained in a 1-month test in which 2.3% moisture was added to the salt at the beginning of the test. The consolidation rate was much more rapid than in any of the dry salt tests. The fracture healing program included 20 permeability tests conducted on fractured and unfractured samples. The tests were conducted in a Hoek cell at hydrostatic pressures up to 3000 psi (20.6 MPa) with durations up to 8 days. For the natural rock salt tested, permeability was strongly dependent on confining pressure and time. The effect of confining pressure was much weaker in the artificial salt. In most cases the combined effects of time and pressure were to reduce the permeability of fractured samples to the same order of magnitude (or less) as the permeability measured prior to fracturing.

Not Available

1987-01-01T23:59:59.000Z

95

Hydraulic fracturing in a naturally fractured reservoir  

SciTech Connect (OSTI)

Hydraulic fracturing of wells in naturally fractured reservoirs can differ dramatically from fracturing wells in conventional isotropic reservoirs. Fluid leakoff is the primary difference. In conventional reservoirs, fluid leakoff is controlled by reservoir matrix and fracture fluid parameters. The fluid leakoff rate in naturally fractured reservoirs is typically excessive and completely dominated by the natural fractures. This paper presents several field examples of a fracture stimulation program performed on the naturally fractured Devonia carbonate of West Texas. Qualitative pressure decline analysis and net treating pressure interpretation techniques were utilized to evaluate the existence of natural fractures in the Devonian Formation. Quantitative techniques were utilized to assess the importance of the natural fractures to the fracturing process. This paper demonstrates that bottomhole pressure monitoring of fracture stimulations has benefits over conducting minifrac treatments in naturally fractured reservoirs. Finally, the results of this evaluation were used to redesign fracture treatments to ensure maximum productivity and minimize costs.

Britt, L.K.; Hager, C.J.; Thompson, J.W.

1994-12-31T23:59:59.000Z

96

Laboratory testing of cement grouting of fractures in welded tuff  

SciTech Connect (OSTI)

Fractures in the rock mass surrounding a repository and its shafts, access drifts, emplacement rooms and holes, and exploratory or in-situ testing holes, may provide preferential flowpaths for the flow of groundwater or air, potentially containing radionuclides. Such cracks may have to be sealed. The likelihood that extensive or at least local grouting will be required as part of repository sealing has been noted in numerous publications addressing high level waste repository closing. The objective of this work is to determine the effectiveness of fracture sealing (grouting) in welded tuff. Experimental work includes measurement of intact and fracture permeability under various normal stresses and injection pressures. Grout is injected into the fractures. The effectiveness of grouting is evaluated in terms of grout penetration and permeability reduction, compared prior to and after grouting. Analysis of the results include the effect of normal stress, injection pressure, fracture roughness, grout rheology, grout bonding, and the radial extent of grout penetration. Laboratory experiments have been performed on seventeen tuff cylinders with three types of fractures: (1) tension induced cracks, (2) natural fractures, and (3) sawcuts. Prior to grouting, the hydraulic conductivity of the intact rock and of the fractures is measured under a range of normal stresses. The surface topography of the fracture is mapped, and the results are used to determine aperture distributions across the fractures. 72 refs., 76 figs., 25 tabs.

Sharpe, C.J.; Daemen, J.J.

1991-03-01T23:59:59.000Z

97

Advanced hydraulic fracturing methods to create in situ reactive barriers  

SciTech Connect (OSTI)

This article describes the use of hydraulic fracturing to increase permeability in geologic formations where in-situ remedial action of contaminant plumes will be performed. Several in-situ treatment strategies are discussed including the use of hydraulic fracturing to create in situ redox zones for treatment of organics and inorganics. Hydraulic fracturing methods offer a mechanism for the in-situ treatment of gently dipping layers of reactive compounds. Specialized methods using real-time monitoring and a high-energy jet during fracturing allow the form of the fracture to be influenced, such as creation of assymmetric fractures beneath potential sources (i.e. tanks, pits, buildings) that should not be penetrated by boring. Some examples of field applications of this technique such as creating fractures filled with zero-valent iron to reductively dechlorinate halogenated hydrocarbons, and the use of granular activated carbon to adsorb compounds are discussed.

Murdoch, L. [FRX Inc., Cincinnati, OH (United States)]|[Clemson Univ., SC (United States). Dept. of Geological Sciences; Siegrist, B.; Meiggs, T. [Oak Ridge National Lab., TN (United States)] [and others

1997-12-31T23:59:59.000Z

98

Bipolar Outflows and the Evolution of Stars  

E-Print Network [OSTI]

Hypersonic bipolar outflows are a ubiquitous phenomena associated with both young and highly evolved stars. Observations of Planetary Nebulae, the nebulae surrounding Luminous Blue Variables such as $\\eta$ Carinae, Wolf Rayet bubbles, the circumstellar environment of SN 1987A and Young Stellar Objects all revealed high velocity outflows with a wide range of shapes. In this paper I review the current state of our theoretical understanding of these outflows. Beginning with Planetary Nebulae considerable progress has been made in understanding bipolar outflows as the result of stellar winds interacting with the circumstellar environment. In what has been called the "Generalized Wind Blown Bubble" (GWBB) scenario, a fast tenuous wind from the central star expands into a ambient medium with an aspherical (toroidal) density distribution. Inertial gradients due to the gaseous torus quickly lead to an expanding prolate or bipolar shell of swept-up gas bounded by strong shock waves. Numerical simulations of the GWBB scenario show a surprisingly rich variety of gasdynamical behavior, allowing models to recover many of the observed properties of stellar bipolar outflows including the development of collimated supersonic jets. In this paper we review the physics behind the GWBB scenario in detail and consider its strengths and weakness. Alternative models involving MHD processes are also examined. Applications of these models to each of the principle classes of stellar bipolar outflow (YSO, PNe, LBV, SN87A) are then reviewed. Outstanding issues in the study of bipolar outflows are considered as are those questions which arise when the outflows are viewed as a single class of phenomena occuring across the HR diagram.

Adam Frank

1998-05-20T23:59:59.000Z

99

Enhanced oil recovery through water imbibition in fractured reservoirs using Nuclear Magnetic Resonance  

E-Print Network [OSTI]

Conventional waterflooding methods of oil recovery are difficult to apply when reservoirs show evidence of natural fractures, because injected water advances through paths of high permeability, and oil trapped in the rock matrix system...

Hervas Ordonez, Rafael Alejandro

1994-01-01T23:59:59.000Z

100

A PKN Hydraulic Fracture Model Study and Formation Permeability Determination  

E-Print Network [OSTI]

. 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...

Xiang, Jing

2012-02-14T23:59:59.000Z

Note: This page contains sample records for the topic "outflow fracture permeability" 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

Reservoir-Scale Fracture Permeability in the Dixie Valley, Nevada,  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revisionEnvReviewNonInvasiveExplorationUT-g Grant of Access(CaliforniaProduction (RECP) inGeothermal Field | Open

102

Remediation of DNAPLs in Low Permeability Soils. Innovative Technology Summary Report  

SciTech Connect (OSTI)

Dense, non-aqueous phase liquid (DNAPL) compounds like trichloroethene (TCE) and perchloroethene (PCE) are prevalent at U. S. Department of Energy (DOE), other government, and industrial sites. Their widespread presence in low permeability media (LPM) poses severe challenges for assessment of their behavior and implementation of effective remediation technologies. Most remedial methods that involve fluid flow perform poorly in LPM. Hydraulic fracturing can improve the performance of remediation methods such as vapor extraction, free-product recovery, soil flushing, steam stripping, bioremediation, bioventing, and air sparging in LPM by enhancing formation permeability through the creation of fractures filled with high-permeability materials, such as sand. Hydraulic fracturing can improve the performance of other remediation methods such as oxidation, reductive dechlorination, and bioaugmentation by enhancing delivery of reactive agents to the subsurface. Hydraulic fractures are typically created using a 2-in. steel casing and a drive point pushed into the subsurface by a pneumatic hammer. Hydraulic fracturing has been widely used for more than 50 years to stimulate the yield of wells recovering oil from rock at great depth and has recently been shown to stimulate the yield of wells recovering contaminated liquids and vapors from LPM at shallow depths. Hydraulic fracturing is an enabling technology for improving the performance of some remedial methods and is a key element in the implementation of other methods. This document contains information on the above-mentioned technology, including description, applicability, cost, and performance data.

None

2000-09-01T23:59:59.000Z

103

Hydraulic fracturing-1  

SciTech Connect (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

104

theoretical and applied fracture  

E-Print Network [OSTI]

theoretical and applied fracture mechanics ELSEVIER Theoretical and Applied Fracture Mechanics 00 and Applied Fracture Mechanics 00 (1995) 000-000 Recently, some European countries developed defect specific. A suitable probabilistic fracture mechanic

Cizelj, Leon

105

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...

Xue, Wenxu

2011-02-22T23:59:59.000Z

106

Predictions for Observing Protostellar Outflows with ALMA  

E-Print Network [OSTI]

Protostellar outflows provide a means to probe the accretion process of forming stars and their ability to inject energy into their surroundings. However, conclusions based on outflow observations depend upon the degree of accuracy with which their properties can be estimated. We examine the quality of Atacama Large Millimeter/submillimeter Array (ALMA) observations of protostellar outflows by producing synthetic $^{12}$CO(1-0) and $^{13}$CO(1-0) observations of numerical simulations. We use various ALMA configurations, observational parameters, and outflow inclinations to assess how accurately different assumptions and setups can recover underlying properties. We find that more compact arrays and longer observing times can improve the mass and momentum recovery by a factor of two. During the first $\\sim$0.3 Myr of evolution, $^{12}$CO(1-0) is optically thick, even for velocities $|v|\\ge 1$ km s$^{-1}$, and outflow mass is severely underestimated without an optical depth correction. Likewise, $^{13}$CO(1-0) i...

Bradshaw, C; Arce, H G

2015-01-01T23:59:59.000Z

107

MULTI-PHASE FRACTURE-MATRIX INTERACTIONS UNDER STRESS CHANGES  

SciTech Connect (OSTI)

The main objectives of this project are to quantify the changes in fracture porosity and multiphase transport properties as a function of confining stress. These changes will be integrated into conceptual and numerical models that will improve our ability to predict and optimize fluid transport in fractured system. This report details our progress on: (1) developing the direct experimental measurements of fracture aperture and topology using high-resolution x-ray microtomography, (2) modeling of fracture permeability in the presence of asperities and confining stress, and (3) simulation of two-phase fluid flow in a fracture and a layered matrix. The three-dimensional surface that describes the large-scale structure of the fracture in the porous medium can be determined using x-ray micro-tomography with significant accuracy. The distribution of fracture aperture is a difficult issue that we are studying and developing methods of quantification. The difficulties are both numerical and conceptual. Numerically, the three-dimensional data sets include millions, and sometimes, billions of points, and pose a computational challenge. The conceptual difficulties derive from the rough nature of the fracture surfaces, and the heterogeneous nature of the rock matrix. However, the high-resolution obtained by the imaging system provides us a much needed measuring environment on rock samples that are subjected to simultaneous fluid flow and confining stress. Pilot multi-phase experiments have been performed, proving the ability to detect two phases in certain large fractures. The absolute permeability of a fracture depends on the behavior of the asperities that keep it open. A model is being developed that predicts the permeability and average aperture of a fracture as a function of time under steady flow of water including the pressure solution at the asperity contact points. Several two-phase flow experiments in the presence of a fracture tip were performed in the past. At the present time, we are developing an inverse process using a simulation model to understand the fluid flow patterns in the presence of a fracture, and the interactions between fluid flow in the fracture and the adjacent matrix. Preliminary results demonstrate that the flow patterns are significantly impacted by the presence of the fracture. Bypassing is quantified and we expect to be able to extract from the modeling the distribution of properties in the fracture and the adjacent matrix.

A.S. Grader; D. Elsworth; P.M. Halleck; F. Alvarado; H. Yasuhara; A. Alajmi; Z. Karpyn

2002-10-28T23:59:59.000Z

108

Gas permeability of carbon aerogels  

SciTech Connect (OSTI)

Carbon aerogels are synthesized via the aqueous polycondensation of resorcinol with formaldehyde, followed by supercritical drying and subsequent pyrolysis at 1050 [degree]C. As a result of their interconnected porosity, ultrafine cell/pore size, and high surface area, carbon aerogels have many potential applications such as supercapacitors, battery electrodes, catalyst supports, and gas filters. The performance of carbon aerogels in the latter two applications depends on the permeability or gas flow conductance in these materials. By measuring the pressure differential across a thin specimen and the nitrogen gas flow rate in the viscous regime, the permeability of carbon aerogels was calculated from equations based upon Darcy's law. Our measurements show that carbon aerogels have permeabilities on the order of 10[sup [minus]12] to 10[sup [minus]10] cm[sup 2] over the density range from 0.05--0.44 g/cm[sup 3]. Like many other aerogel properties, the permeability of carbon aerogels follows a power law relationship with density, reflecting differences in the average mesopore size. Comparing the results from this study with the permeability of silica aerogels reported by other workers, we found that the permeability of aerogels is governed by a simple universal flow equation. This paper discusses the relationship between permeability, pore size, and density in carbon aerogels.

Kong, F.; LeMay, J.D.; Hulsey, S.S.; Alviso, C.T.; Pekala, R.W. (Chemistry and Materials Science Department, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States))

1993-12-01T23:59:59.000Z

109

The evolution of hydraulic fracturing in the Almond formation  

SciTech Connect (OSTI)

This study draws from a database of over 600 wells to evaluate reservoir, production and treatment characteristics in the low-permeability, naturally-fractured Almond formation. Treatment-induced damage can be significant; damage mechanisms are discussed and ways are shown to mitigate these problems. An effective fracture stimulation design combines proppant scheduling of the late 1970`s with fluid and gel-breaker systems of today.

Cramer, D.D.

1995-12-31T23:59:59.000Z

110

Self-potential observations during hydraulic fracturing  

SciTech Connect (OSTI)

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

111

The lifecycle of powerful AGN outflows  

E-Print Network [OSTI]

During the course of this conference, much evidence was presented that points to an intimate connection between the energetic outflows driven by AGN and the energy budget and quite possibly also the evolution of their gaseous environments. However, it is still not clear if and how the AGN activity is triggered by the cooling gas, how long the activity lasts for and how these effects give rise to the observed distribution of morphologies of the outflows. In this contribution we concentrate on the high radio luminosity end of the AGN population. While most of the heating of the environmental gas may be due to less luminous and energetic outflows, these more powerful objects have a very profound influence on their surroundings. We will describe a simple model for powerful radio galaxies and radio-loud quasars that explains the dichotomy of their large-scale radio morphologies as well as their radio luminosity function.

Christian R. Kaiser; Philip N. Best

2006-11-07T23:59:59.000Z

112

The lifecycle of powerful AGN outflows  

E-Print Network [OSTI]

During the course of this conference, much evidence was presented that points to an intimate connection between the energetic outflows driven by AGN and the energy budget and quite possibly also the evolution of their gaseous environments. However, it is still not clear if and how the AGN activity is triggered by the cooling gas, how long the activity lasts for and how these effects give rise to the observed distribution of morphologies of the outflows. In this contribution we concentrate on the high radio luminosity end of the AGN population. While most of the heating of the environmental gas may be due to less luminous and energetic outflows, these more powerful objects have a very profound influence on their surroundings. We will describe a simple model for powerful radio galaxies and radio-loud quasars that explains the dichotomy of their large-scale radio morphologies as well as their radio luminosity function.

Kaiser, C R; Kaiser, Christian R.; Best, Philip N.

2006-01-01T23:59:59.000Z

113

Seismic signatures of the Lodgepole fractured reservoir in Utah-Wyoming overthrust belt  

SciTech Connect (OSTI)

In low porosity, low permeability zones, natural fractures are the primary source of permeability which affect both production and injection of fluids. The open fractures do not contribute much to porosity, but they provide an increased drainage network to any porosity. An important approach to characterizing the fracture orientation and fracture permeability of reservoir formations is one based upon the effects of such conditions on the propagation of acoustic and seismic waves in the rock. We present the feasibility of using seismic measurement techniques to map the fracture zones between wells spaced 2400 ft at depths of about 1000 ft. For this purpose we constructed computer models (which include azimuthal anisotropy) using Lodgepole reservoir parameters to predict seismic signatures recorded at the borehole scale, crosswell scale, and 3 D seismic scale. We have integrated well logs with existing 2D surfaces seismic to produce petrophysical and geological cross sections to determine the reservoir parameters and geometry for the computer models. In particular, the model responses are used to evaluate if surface seismic and crosswell seismic measurements can capture the anisotropy due to vertical fractures. Preliminary results suggested that seismic waves transmitted between two wells will propagate in carbonate fracture reservoirs, and the signal can be received above the noise level at the distance of 2400 ft. In addition, the large velocities contrast between the main fracture zone and the underlying unfractured Boundary Ridge Member, suggested that borehole reflection imaging may be appropriate to map and fracture zone thickness variation and fracture distributions in the reservoir.

Parra, J.; Collier, H.; Angstman, B.

1997-08-01T23:59:59.000Z

114

In situ permeability modification using gelled polymer systems. Topical report, June 10, 1996--April 10, 1997  

SciTech Connect (OSTI)

Results from a research program on the application of gelled polymer technology for in situ permeability modification are presented in this report. The objective of this technology when used with displacement processes such as waterflooding is to reduce the permeability in fractures and/or high permeability matrix zones to improve volumetric sweep efficiency of the displacement process. In production wells, the objective is to reduce water influx. The research program is focused on five areas: gel treatment in fractured systems; gel treatment in carbonate rocks; in-depth placement of gels; gel systems for application in carbon dioxide flooding; and gel treatment in production wells. The research program is primarily an experimental program directed at improving the understanding of gelled polymer systems and how these systems can be used to increase oil recovery from petroleum reservoirs. A summary of progress for research conducted in the first 10 months of a 28 month program is described in the following sections.

Green, D.W.; Willhite, G.P.; McCool, C.S.; Heppert, J.A.; Vossoughi, S.

1997-10-01T23:59:59.000Z

115

In situ permeability modification using gelled polymer systems. Annual report, April 11, 1997--April 10, 1998  

SciTech Connect (OSTI)

Results from a research program on the application of gelled polymer technology for in situ permeability modification are presented in this report. The objective of this technology when used with displacement processes such as waterflooding is to reduce the permeability in fractures and/or high permeability matrix zones to improve volumetric sweep efficiency of the displacement process. In production wells, the objective is to reduce water influx. The research program focused on five areas: Gel treatment in fractured systems; Gel treatment in carbonate rocks; In-depth placement of gels; Gel systems for application in carbon dioxide flooding; and Gel treatment in production wells. The research program is primarily an experimental program directed toward improving the understanding of gelled polymer systems and how these systems can be used to increase oil recovery from petroleum reservoirs. A summary of progress for research conducted in the second 12 month period of a 28 month program is described.

Green, D.W.; Willhite, G.P.; McCool, C.S.; Heppert, J.A.; Vossoughi, S.; Michnick, M.J.

1998-09-01T23:59:59.000Z

116

Identification and quantification of fracture behavior through reservoir simulation  

SciTech Connect (OSTI)

This study demonstrated the use of reservoir simulation as a tool for quantifying and describing the relative significance of fracture and matrix flow units to overall reservoir storage capacity and transmissibility in a field development example. A high matrix porosity Pennsylvanian age sandstone oil reservoir, that is currently undergoing the early stages of secondary recovery by waterflood, was studied. Unexpected early water breakthrough indicated the presence of a high directional permeability fracture system superimposed on the high porosity matrix system. To further understand the reservoir behavior, improve field performance and to quantify the relative contributions of fracture and matrix units to permeability and storage capacity, a reservoir simulation and characterization project was initiated. Well test, well log, tracer and geologic data were integrated into the simulation project. The integrated study indicated that the fractures exhibited high directional permeability but low storage capacity relative to the matrix portion of the reservoir. Although fractures heavily influenced overall fluid flow behavior, they did not contain large storage capacity. The system had a low calculated fracture intensity index. Reservoir simulation enabled the quantification of the relative importance of the two flow systems which in turn had a large impact on total reserves estimates and production forecasting. Simulation results indicated a need to realign injector and producer patterns which improved production rates and ultimate recovery.

Cline, S. [Univ. of Oklahoma, Oklahoma City, OK (United States)]|[Hefner Corporation, Oklahoma City, OK (United States)

1995-08-01T23:59:59.000Z

117

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

SciTech Connect (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

118

A Thermoelastic Hydraulic Fracture Design Tool for Geothermal Reservoir Development  

SciTech Connect (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

119

Identification of Successful Practices in Hydraulic Fracturing Using Intelligent Data Mining Tools; Application to the Codell Formation in the DJ Basin  

E-Print Network [OSTI]

SPE 77597 Identification of Successful Practices in Hydraulic Fracturing Using Intelligent Data to identify successful practices in hydraulic fracturing. The Codell formation is a low permeability sandstone candidate selection and identify successful practices. Hydraulic fracturing is an economic way of increasing

Mohaghegh, Shahab

120

Over the past 10 years, there has been a consistent increase in using 3D P-wave data to characterize fractures, which is  

E-Print Network [OSTI]

to characterize fractures, which is critical for ensuring economic oil and gas production in tight formations of otherwise low permeability. Here, we pre- sent a case study of fracture detection using 3D P-wave seismic, of zones of high fracture density that are residual-oil-charged. A major aspect of this study is to compare

Edinburgh, University of

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121

Neo-tectonic fracturing after emplacement of quaternary granitic pluton in the Kakkonda geothermal field, Japan  

SciTech Connect (OSTI)

The fracture which occurs in the Kakkonda geothermal system was formed by neo-tectonic stress after the emplacement of the neo-granite (Quaternary Kakkonda Granite) at middle Pleistocene to recent. The characteristic contrast in permeability at ca.1.5 km is strongly controlled by the contact metamorphic zone, especially cordierite and higher grade metamorphic zones, in which the high temperature (320{degrees}C<) and low permeable deep reservoir was created. The five geothermal wells 2.5-3.0 km deep have clarified that a microearthquake zone below -1.0 km shows high permeability especially at the margin of the Kakkonda Granite, and low permeability outside of a microearthquake zone. The Kakkonda Granite is a composite pluton which has very few fractures inside of it. Thus, neo-tectonic fracturing has developed in the non-metamorphosed Tertiary formations and the margin of the Kakkonda Granite.

Doi, N.; Kato, O. [JMC Goethermal Eng. Co., Ltd., Iwate-ken (Japan); Kanisawa, S.; Ishikawa, K. [Tohoku Univ., Sendai (Japan)

1995-12-31T23:59:59.000Z

122

Measurement and analysis of fractures in vertical, slant, and horizontal core, with examples from the Mesaverde formation  

SciTech Connect (OSTI)

Optimum analysis of natural fracture characteristics and distributions in reservoirs requires conscientious supervision of coring operations, on-site core processing, careful layout and marketing of the core, and detailed measurement of fracture characteristics. Natural fractures provide information on the in situ permeability system, and coring-induced fractures provide data on the in situ stresses. Fracture data derived from vertical core should include fracture height, type and location of fracture terminations with respect to lithologic heterogeneity, fracture planatary and roughness, and distribution with depth. Fractures in core from either a vertical or a deviated well will yield information on dip, dip azimuth, strike, mineralization, and the orientation of fractures relative to the in situ stresses. Only measurements of fractures in core from a deviated/horizontal well will provide estimates of fracture spacing and porosity. These data can be graphed and cross-plotted to yield semi-quantitative fracture characteristics for reservoir models. Data on the orientations of fractures relative to each other in unoriented core can be nearly as useful as the absolute orientations of fractures. A deviated pilot hole is recommended for fracture assessment prior to a drilling horizontal production well because it significantly enhances the chances of fracture intersection, and therefore of fracture characterization. 35 refs., 20 figs., 2 tabs.

Lorenz, J.C. (Sandia National Labs., Albuquerque, NM (United States)); Hill, R.E. (CER Corp., Las Vegas, NV (United States))

1991-01-01T23:59:59.000Z

123

Hydraulic fracturing technology: Technology evaluation report and application analysis report  

SciTech Connect (OSTI)

Two pilot-scale demonstrations of the hydraulic fracturing technology for enhancing the permeability of contaminated silty clays have been evaluated under the Superfund Innovative Technology Evaluation (SITE) Program. The hydraulic fracturing technology was demonstrated in 1991 and 1992 at a extraction site in Oak Brook, Illinois, and at a bioremediation site near Dayton, Ohio. The technology was jointly developed by the University of Cincinnati (UC) and the Risk Reduction Engineering Laboratory. Tests were also conducted at UC Center Hill Solid and Hazardous Waste Research (Center Hill) Facility by UC. These tests were conducted to determine the factors affecting soil vapor flow through sand-filled hydraulic fractures.

Banerjee, P.

1993-08-01T23:59:59.000Z

124

AVO in azmuthally anisotropic media fracture detection using P ...  

E-Print Network [OSTI]

An enormous amount of natural gas exists in naturally fractured, low-permeability reservoirs. ..... 4.5.4 Center frequencies of pre-stack data . . . . . . . . . . . . . . . 110 .... U.S. energy policy, natural gas may emerge as an alternative fossil fuel to oil.

Wei Chen

125

Water Injection into a Low-Permeability Rock - 1: Hydrofracture Growth  

SciTech Connect (OSTI)

In this paper, we model water injection through a growing vertical hydrofracture penetrating a low-permeability reservoir. The results are useful in oilfield waterflood applications and in liquid waste disposal through reinjection. Using Duhamel's principle, we extend the Gordeyev and Entov (1997) self-similar 2D solution of pressure diffusion from a growing fracture to the case of variable injection pressure. The flow of water injected into a low-permeability rock is almost perpendicular to the fracture for a time sufficiently long to be of practical interest. We revisit Carter's model of 1D fluid injection (Howard and Fast, 1957) and extend it to the case of variable injection pressure. We express the cumulative injection through the injection pressure and effective fracture area. Maintaining fluid injection above a reasonable minimal value leads inevitably to fracture growth regardless of the injector design and the injection policy. The average rate of fracture growth can be predicted from early injection. A smart injection controller that can prevent rapid fracture growth is needed.

Patzek, Tad W.; Silin, Dmitriy B.

1999-07-27T23:59:59.000Z

126

Multi-Phase Fracture-Matrix Interactions Under Stress Changes  

SciTech Connect (OSTI)

The main objectives of this project are to quantify the changes in fracture porosity and multi-phase transport properties as a function of confining stress. These changes will be integrated into conceptual and numerical models that will improve our ability to predict and optimize fluid transport in fractured system. This report details our progress on: (a) developing the direct experimental measurements of fracture aperture and topology and fluid occupancy using high-resolution x-ray micro-tomography, (b) counter-current fluid transport between the matrix and the fracture, (c) studying the effect of confining stress on the distribution of fracture aperture and two-phase flow, and (d) characterization of shear fractures and their impact on multi-phase flow. The three-dimensional surface that describes the large-scale structure of the fracture in the porous medium can be determined using x-ray micro-tomography with significant accuracy. Several fractures have been scanned and the fracture aperture maps have been extracted. The success of the mapping of fracture aperture was followed by measuring the occupancy of the fracture by two immiscible phases, water and decane, and water and kerosene. The distribution of fracture aperture depends on the effective confining stress, on the nature of the rock, and the type and distribution of the asperities that keep the fracture open. Fracture apertures at different confining stresses were obtained by micro-tomography covering a range of about two thousand psig. Initial analysis of the data shows a significant aperture closure with increase in effective confining stress. Visual and detailed descriptions of the process are shown in the report. Both extensional and shear fractures have been considered. A series of water imbibition tests were conducted in which water was injected into a fracture and its migration into the matrix was monitored with CT and DR x-ray techniques. The objective was to understand the impact of the fracture, its topology and occupancy on the nature of mass transfer between the matrix and the fracture. Counter-current imbibition next to the fracture was observed and quantified, including the influence of formation layering. A group of Shear fractures were studied, with layers perpendicular and parallel to the main axis of the sample. The structures of the fractures as well as their impact on absolute permeability and on oil displacement by water were evaluated. Shear fractures perpendicular to the layers lead to a wide distribution of pores and to an overall increase in absolute permeability. Shear fractures parallel to the layers lead to an overall increase in absolute permeability, but a decrease in displacement efficiency. This DoE project funded or partially funded three Ph.D. and four M.Sc. students at the Pennsylvania State University. The results from the research have yielded several abstracts, presentations and papers. Much of the work is still in the process of being published.

A.S. Grader; D. Elsworth; P.M. Halleck; F. Alvarao; A. Alajmi; Z. Karpyn; N. Mohammed; S. Al-Enezi

2005-12-07T23:59:59.000Z

127

Simulation studies to evaluate the effect of fracture closure on the performance of naturally fractured reservoirs. Annual report  

SciTech Connect (OSTI)

The first of a three-year research program to evaluate the effect of fracture closure on the recovery of oil and gas from naturally fractured reservoirs has been completed. The objectives of the study are to (1) evaluate the reservoir conditions where fracture closure is significant, and (2) evaluate innovative fluid injection techniques capable of maintaining pressure within the reservoir. Simulation studies were conducted with a dual porosity simulator capable of simulating the performance of vertical and horizontal wells. Each simulator was initialized using properties typical of the Austin Chalk reservoir in Pearsall Field, Texas. Simulations of both vertical and horizontal well performance were made assuming that fracture permeability was insensitive to pressure change. Sensitivity runs indicate that the simulator is predicting the effects of critical reservoir parameters in a logical and consistent manner. The results to-date confirm that horizontal wells can increase both oil recovery rate and total oil recovery from naturally fractured reservoirs. The year one simulation results will provide the baseline for the ongoing study which will evaluate the performance degradation caused by the sensitivity of fracture permeability to pressure change, and investigate fluid injection pressure maintenance as a means to improve oil recovery performance. The study is likely to conclude that fracture closure decreases oil recovery and that pressure support achieved through fluid injection could be beneficial in improving recovery.

Not Available

1991-10-01T23:59:59.000Z

128

Fracture Properties From Seismic Scattering  

E-Print Network [OSTI]

Fractures scatter seismic energy and this energy can be analyzed to provide information about fracture

Burns, Daniel R.

2007-01-01T23:59:59.000Z

129

Seismic characterization of fractures  

E-Print Network [OSTI]

Seismic characterization of fractures. José M. Carcione, OGS, Italy. Fractured geological formations are generally represented with a stress-strain relation.

JM Carcione

2014-06-07T23:59:59.000Z

130

Multi-Site Application of the Geomechanical Approach for Natural Fracture Exploration  

SciTech Connect (OSTI)

In order to predict the nature and distribution of natural fracturing, Advanced Resources Inc. (ARI) incorporated concepts of rock mechanics, geologic history, and local geology into a geomechanical approach for natural fracture prediction within mildly deformed, tight (low-permeability) gas reservoirs. Under the auspices of this project, ARI utilized and refined this approach in tight gas reservoir characterization and exploratory activities in three basins: the Piceance, Wind River and the Anadarko. The primary focus of this report is the knowledge gained on natural fractural prediction along with practical applications for enhancing gas recovery and commerciality. Of importance to tight formation gas production are two broad categories of natural fractures: (1) shear related natural fractures and (2) extensional (opening mode) natural fractures. While arising from different origins this natural fracture type differentiation based on morphology is sometimes inter related. Predicting fracture distribution successfully is largely a function of collecting and understanding the available relevant data in conjunction with a methodology appropriate to the fracture origin. Initially ARI envisioned the geomechanical approach to natural fracture prediction as the use of elastic rock mechanics methods to project the nature and distribution of natural fracturing within mildly deformed, tight (low permeability) gas reservoirs. Technical issues and inconsistencies during the project prompted re-evaluation of these initial assumptions. ARI's philosophy for the geomechanical tools was one of heuristic development through field site testing and iterative enhancements to make it a better tool. The technology and underlying concepts were refined considerably during the course of the project. As with any new tool, there was a substantial learning curve. Through a heuristic approach, addressing these discoveries with additional software and concepts resulted in a stronger set of geomechanical tools. Thus, the outcome of this project is a set of predictive tools with broad applicability across low permeability gas basins where natural fractures play an important role in reservoir permeability. Potential uses for these learnings and tools range from rank exploration to field-development portfolio management. Early incorporation of the permeability development concepts presented here can improve basin assessment and direct focus to the high potential areas within basins. Insight into production variability inherent in tight naturally fractured reservoirs leads to improved wellbore evaluation and reduces the incidence of premature exits from high potential plays. A significant conclusion of this project is that natural fractures, while often an important, overlooked aspect of reservoir geology, represent only one aspect of the overall reservoir fabric. A balanced perspective encompassing all aspects of reservoir geology will have the greatest impact on exploration and development in the low permeability gas setting.

R. L. Billingsley; V. Kuuskraa

2006-03-31T23:59:59.000Z

131

Simulating infiltration tests in fractured basalt at the Box Canyon Site, Idaho  

SciTech Connect (OSTI)

The results of a series of ponded infiltration tests in variably saturated fractured basalt at Box Canyon, Idaho, were used to build confidence in conceptual and numerical modeling approaches used to simulate infiltration in fractured rock. Specifically, we constructed a dual-permeability model using TOUGH2 to represent both the matrix and fracture continua of the upper basalt flow at the Box Canyon site. A consistent set of hydrogeological parameters was obtained by calibrating the model to infiltration front arrival times in the fracture continuum as inferred from bromide samples collected from fracture/borehole intersections observed during the infiltrating tests. These parameters included the permeability of the fracture and matrix continua, the interfacial area between the fracture and matrix continua, and the porosity of the fracture continuum. To calibrate the model, we multiplied the fracture-matrix interfacial area by a factor between 0.1 and 0.01 to reduce imbibition of water from the fracture continuum into the matrix continuum during the infiltration tests. Furthermore, the porosity of the fracture continuum, as calculated using the fracture aperture inferred from pneumatic-test permeabilities, was increased by a factor of 50 yielding porosity values for the upper basalt flow in the range of 0.01 to 0.02. The fracture-continuum porosity was a highly sensitive parameter controlling the arrival times of the simulated infiltration fronts. Porosity values are consistent with those determined during the Large-Scale Aquifer Pumping and Infiltration Test at the Idaho National Engineering and Environmental Laboratory.

Unger, Andre J.A.; Faybishenko, Boris; Bodvarsson, Gudmundur S.; Simmons, Ardyth M.

2003-04-01T23:59:59.000Z

132

CARMA OBSERVATIONS OF PROTOSTELLAR OUTFLOWS IN NGC 1333  

SciTech Connect (OSTI)

We present observations of outflows in the star-forming region NGC 1333 using the Combined Array for Research in Millimeter-Wave Astronomy (CARMA). We combined the {sup 12}CO and {sup 13}CO (1-0) CARMA mosaics with data from the 14 m Five College Radio Astronomy Observatory to probe the central, most dense, and active region of this protostellar cluster at scales from 5'' to 7' (or 1000 AU to 0.5 pc at a distance of 235 pc). We map and identify {sup 12}CO outflows, and along with {sup 13}CO data we estimate their mass, momentum, and energy. Within the 7' Multiplication-Sign 7' map, the 5'' resolution allows for a detailed study of morphology and kinematics of outflows and outflow candidates, some of which were previously confused with other outflow emission in the region. In total, we identify 22 outflow lobes, as well as 9 dense circumstellar envelopes marked by continuum emission, of which 6 drive outflows. We calculate a total outflow mass, momentum, and energy within the mapped region of 6 M{sub Sun }, 19 M{sub Sun} km s{sup -1}, and 7 Multiplication-Sign 10{sup 44} erg, respectively. Within this same region, we compare outflow kinematics with turbulence and gravitational energy, and we suggest that outflows are likely important agents for the maintenance of turbulence in this region. In the earliest stages of star formation, outflows do not yet contribute enough energy to totally disrupt the clustered region where most star formation is happening, but have the potential to do so as the protostellar sources evolve. Our results can be used to constrain outflow properties, such as outflow strength, in numerical simulations of outflow-driven turbulence in clusters.

Plunkett, Adele L.; Arce, Hector G. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven CT 06520 (United States); Corder, Stuartt A. [Joint ALMA Observatory, Av. Alonso de Cordova 3107, Vitacura, Santiago (Chile); Mardones, Diego [Departameto de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Sargent, Anneila I. [Astronomy Department, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Schnee, Scott L., E-mail: adele.plunkett@yale.edu [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)

2013-09-01T23:59:59.000Z

133

THE OUTFLOWING WIND OF V1057 CYGNI  

SciTech Connect (OSTI)

In 1970-1971, V1057 Cyg rose from about m {sub pg} {approx} 16 to a peak near 10.5 mag. It has subsequently faded to about B = 15, and although it appeared to be a T Tauri star (TTS) before the outburst, it now resembles a rather peculiar rapidly rotating G-type supergiant. Before the outburst, it showed unmistakable evidence of high-velocity outflow (by the suppression of emission Ca II {lambda}3968 by the P Cyg absorption component of H{epsilon} {lambda}3970). Such outflow absorptions are currently found at many strong lines (H{alpha}, Na I D{sub 1,2}, K I {lambda}{lambda}7664, 7698, Ca II {lambda}{lambda}8498, 8662, ...). The same phenomenon has since been observed in a number of other FUors near maximum light, suggesting that it is a FUor characteristic that clearly differs from the outflows found in TTSs. The Li I resonance line at 6707 A is relatively weak, and on high-resolution spectra obtained between 1997 and 2008 showed variable absorption structure on its shortward side that probably represents wind structure that is lost in the stronger lines. In addition, a narrow emission line at 6707 A persists throughout the series and is the counterpart of the sharp emission lines that occur near the centers of many of the broad stellar absorption lines (v sin i = 55 km s{sup -1}) and that were responsible for the line-splitting phenomenon formerly regarded as evidence of a Keplerian disk. Given the evidence of a quasi-permanent outflow at V1057 Cyg, the hypothesis is advanced that a FUor outburst may be the result of a rapidly rotating TTS having contracted to a point of rotational instability, at which time it sheds enough material and angular momentum to resume contraction, until the next such event.

Herbig, G. H. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)], E-mail: herbig@ifa.hawaii.edu

2009-08-15T23:59:59.000Z

134

Colloidosomes: Selectively Permeable Capsules Composed  

E-Print Network [OSTI]

structures, which we call "col- loidosomes," are hollow, elastic shells whose permeability and elasticity can at the surface of water drops can be used to fabricate nano- or microporous capsules (1­5, 9); other fluid a flexible approach to the prep- aration of hollow, elastic capsules, with sizes ranging from micrometers

Weeks, Eric R.

135

Fracture-Flow-Enhanced Solute Diffusion into Fractured Rock  

E-Print Network [OSTI]

influence of effective fracture aperture, Water Resourcesa system of parallel fractures, Water Resources Research,solutions for a single fractures, Water Resources Research,

Wu, Yu-Shu; Ye, Ming; Sudicky, E.A.

2008-01-01T23:59:59.000Z

136

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

DOE Patents [OSTI]

An improved method and apparatus as disclosed for measuring the permeability of multiple phases through a rock fracture. The improvement in the method comprises delivering the respective phases through manifolds to uniformly deliver and collect the respective phases to and from opposite edges of the rock fracture in a distributed manner across the edge of the fracture. The improved apparatus comprises first and second manifolds comprising bores extending within porous blocks parallel to the rock fracture for distributing and collecting the wetting phase to and from surfaces of the porous blocks, which respectively face the opposite edges of the rock fracture. The improved apparatus further comprises other manifolds in the form of plenums located adjacent the respective porous blocks for uniform delivery of the non-wetting phase to parallel grooves disposed on the respective surfaces of the porous blocks facing the opposite edges of the rock fracture and generally perpendicular to the rock fracture.

Persoff, Peter (Oakland, CA); Pruess, Karsten (Berkeley, CA); Myer, Larry (Benicia, CA)

1994-01-01T23:59:59.000Z

137

Review of hydrogen isotope permeability through materials  

SciTech Connect (OSTI)

This report is the first part of a comprehensive summary of the literature on hydrogen isotope permeability through materials that do not readily form hydrides. While we mainly focus on pure metals with low permeabilities because of their importance to tritium containment, we also give data on higher-permeability materials such as iron, nickel, steels, and glasses.

Steward, S.A.

1983-08-15T23:59:59.000Z

138

STEAM-WATER RELATIVE PERMEABILITY A DISSERTATION  

E-Print Network [OSTI]

STEAM-WATER RELATIVE PERMEABILITY A DISSERTATION SUBMITTED TO THE DEPARTMENT OF PETROLEUM Laboratory. iv #12;ABSTRACT Steam-water relative permeability curves are required for mathematical models of two-phase geothermal reservoirs. In this study, drainage steam- water relative permeabilities were

Stanford University

139

A robust and accurate outflow boundary condition for ...  

E-Print Network [OSTI]

Jan 3, 2014 ... expressions (18a)–(18c) satisfy Eq. (3) on the outflow boundaries. ..... formation region marks the initial position of fully shed vortex and the ...

S. Dong

2014-01-15T23:59:59.000Z

140

Stellar Populations, Outflows, and Morphologies of High-Redshift Galaxies  

E-Print Network [OSTI]

strongly on inclination as the wind becomes increasinglyinclination, consistent with the physical picture of windsinclinations, and the outflow geometry of galactic winds.

Kornei, Katherine Anne

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "outflow fracture permeability" 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

Occurrence Frequency of CO Outflows in Massive Protostellar Candidates  

E-Print Network [OSTI]

We mapped 12 massive protostellar candidates in the CO J=2-1 line, which in combination with Zhang et al. (2005) completes an unbiased survey of outflows for all 48 sources with l>50^o in a sample of 101 massive protostellar candidates. We detected outflows in 10 sources, implying 88% occurrence frequency of outflows for the 48 sources. This supports the conclusion of previous studies that bipolar outflows are an integral component in the formation process of massive stars. The vast majority of the observed outflows are much more massive (>10~Mo) and energetic (>100~Mo~km/s) than outflows from low-mass protostars. They also have large mass outflow rates (>2x10^{-4}~Mo/yr), suggesting large (~1x10^{-4}~Mo/yr) accretion rates sufficient to overcome radiation pressure of the central massive protostars. We compared the frequency distribution of collimation factors of 40 massive outflows including those of this study with that of 36 low-mass outflows from the literature, and found NO significant difference between the two. All these results are consistent with the suggestion that massive stars form through accretion as do low-mass stars but with much higher accretion rates.

Kee-Tae Kim; S. E. Kurtz

2006-01-24T23:59:59.000Z

142

ATOMIC HYDROGEN IN A GALACTIC CENTER OUTFLOW  

SciTech Connect (OSTI)

We describe a population of small, high-velocity, atomic hydrogen clouds, loops, and filaments found above and below the disk near the Galactic center. The objects have a mean radius of 15 pc, velocity widths of {approx}14 km s{sup -1}, and are observed at |z| heights up to 700 pc. The velocity distribution of the clouds shows no signature of Galactic rotation. We propose a scenario where the clouds are associated with an outflow from a central star-forming region at the Galactic center. We discuss the clouds as entrained material traveling at {approx}200 km s{sup -1} in a Galactic wind.

McClure-Griffiths, N. M.; Green, J. A.; Hill, A. S. [Australia Telescope National Facility, CSIRO Astronomy and Space Science, Marsfield, NSW 2122 (Australia); Lockman, F. J. [National Radio Astronomy Observatory, Green Bank, WV 24944 (United States); Dickey, J. M. [School of Physics and Mathematics, University of Tasmania, TAS 7001 (Australia); Gaensler, B. M.; Green, A. J., E-mail: naomi.mcclure-griffiths@csiro.au [Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006 (Australia)

2013-06-10T23:59:59.000Z

143

Modeling shear failure and permeability enhancement due to coupled Thermal-Hydrological-Mechanical processes in Enhanced Geothermal Reservoirs  

SciTech Connect (OSTI)

The connectivity and accessible surface area of flowing fractures, whether natural or man-made, is possibly the single most important factor, after temperature, which determines the feasibility of an Enhanced Geothermal System (EGS). Rock deformation and in-situ stress changes induced by injected fluids can lead to shear failure on preexisting fractures which can generate microseismic events, and also enhance the permeability and accessible surface area of the geothermal formation. Hence, the ability to accurately model the coupled thermal-hydrologic-mechanical (THM) processes in fractured geological formations is critical in effective EGS reservoir development and management strategies. The locations of the microseismic events can serve as indicators of the zones of enhanced permeability, thus providing vital information for verification of the coupled THM models. We will describe a general purpose computational code, FEHM, developed for this purpose, that models coupled THM processes during multiphase fluid flow and transport in fractured porous media. The code incorporates several models of fracture aperture and stress behavior combined with permeability relationships. We provide field scale examples of applications to geothermal systems to demonstrate the utility of the method.

Kelkar, Sharad [Los Alamos National Laboratory

2011-01-01T23:59:59.000Z

144

Mechanisms and impact of damage resulting from hydraulic fracturing. Topical report, May 1995-July 1996  

SciTech Connect (OSTI)

This topical report documents the mechanisms of formation damage following hydraulic fracturing and their impact upon gas well productivity. The categories of damage reviewed include absolute or matrix permeability damage, relative permeability alterations, the damage of natural fracture permeability mechanisms and proppant conductivity impairment. Case studies are reviewed in which attempts are made to mitigate each of the damage types. Industry surveys have been conducted to determine the perceptions of the industry on the topic of formation damage following hydraulic fracturing and to identify key formations in which formation damage is a problem. From this information, technical hurdles and new technology needs are identified and estimates are made of the benefits of developing and applying minimum formation damage technology.

Penny, G.S.; Conway, M.W.; Almond, S.W.; Himes, R.; Nick, K.E.

1996-08-01T23:59:59.000Z

145

Simulating galactic outflows with kinetic supernova feedback  

E-Print Network [OSTI]

Feedback from star formation is thought to play a key role in the formation and evolution of galaxies, but its implementation in cosmological simulations is currently hampered by a lack of numerical resolution. We present and test a sub-grid recipe to model feedback from massive stars in cosmological smoothed particle hydrodynamics simulations. The energy is distributed in kinetic form among the gas particles surrounding recently formed stars. The impact of the feedback is studied using a suite of high-resolution simulations of isolated disc galaxies embedded in dark halos with total mass 10^{10} and 10^{12} Msol/h. We focus in particular on the effect of pressure forces on wind particles within the disc, which we turn off temporarily in some of our runs to mimic a recipe that has been widely used in the literature. We find that this popular recipe gives dramatically different results because (ram) pressure forces on expanding superbubbles determine both the structure of the disc and the development of large-scale outflows. Pressure forces exerted by expanding superbubbles puff up the disc, giving the dwarf galaxy an irregular morphology and creating a galactic fountain in the massive galaxy. Hydrodynamic drag within the disc results in a strong increase of the effective mass loading of the wind for the dwarf galaxy, but quenches much of the outflow in the case of the high-mass galaxy.

Claudio Dalla Vecchia; Joop Schaye

2008-05-07T23:59:59.000Z

146

Power spectra of outflow-driven turbulence  

E-Print Network [OSTI]

We investigate the power spectra of outflow-driven turbulence through high-resolution three-dimensional isothermal numerical simulations where the turbulence is driven locally in real-space by a simple spherical outflow model. The resulting turbulent flow saturates at an average Mach number of ~2.5 and is analysed through density and velocity power spectra, including an investigation of the evolution of the solenoidal and compressional components. We obtain a shallow density power spectrum with a slope of ~-1.2 attributed to the presence of a network of localised dense filamentary structures formed by strong shock interactions. The total velocity power spectrum slope is found to be ~-2.0, representative of Burgers shock dominated turbulence model. The density weighted velocity power spectrum slope is measured as ~-1.6, slightly less than the expected Kolmogorov scaling value (slope of -5/3) found in previous works. The discrepancy may be caused by the nature of our real space driving model and we suggest ther...

Moraghan, Anthony; Yoon, Suk-Jin

2015-01-01T23:59:59.000Z

147

IONIZED OUTFLOWS FROM COMPACT STEEP SPECTRUM SOURCES  

SciTech Connect (OSTI)

Massive outflows are known to exist, in the form of extended emission-line regions (EELRs), around about one-third of powerful FR II radio sources. We investigate the origin of these EELRs by studying the emission-line regions around compact-steep-spectrum (CSS) radio galaxies that are younger (10{sup 3}-10{sup 5} yr old) versions of the FR II radio galaxies. We have searched for and analyzed the emission-line regions around 11 CSS sources by taking integral field spectra using Gemini Multi-Object Spectrograph on Gemini North. We fit the [O III] {lambda}5007 line and present the velocity maps for each detected emission-line region. We find, in most cases, that the emission-line regions have multi-component velocity structures with different velocity dispersions and/or flux distributions for each component. The velocity gradients of the emission-line gas are mostly well aligned with the radio axis, suggesting a direct causal link between the outflowing gas and the radio jets. The complex velocity structure may be a result of different driving mechanisms related to the onset of the radio jets. We also present the results from the line-ratio diagnostics we used to analyze the ionization mechanism of the extended gas, which supports the scenario where the emission-line regions are ionized by a combination of active galactic nucleus radiation and shock excitation.

Shih, Hsin-Yi; Stockton, Alan; Kewley, Lisa, E-mail: hsshih@ifa.hawaii.edu, E-mail: stockton@ifa.hawaii.edu, E-mail: lisa.kewley@anu.edu.au [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

2013-08-01T23:59:59.000Z

148

IC5063: AGN driven outflow of warm and cold gas  

E-Print Network [OSTI]

We present new ATCA 17- and 24-GHz radio images and ESO-NTT optical spectra of the radio-loud Seyfert galaxy IC5063, the first galaxy in which a fast (~ 600 km/s) outflow of neutral hydrogen was discovered. The new radio data confirm the triple radio structure with a central core and two resolved radio lobes. This implies that the previously detected fast outflow of neutral gas is occurring off-nucleus, near a radio lobe about 0.5 kpc from the core. The ionised gas shows complex kinematics in the region co-spatial with the radio emission. Broad and blueshifted (~ 500 km/s) emission is observed in the region of the radio lobe, at the same location as the blueshifted HI absorption. The velocity of the ionised outflow is similar to the one found in HI. The first order correspondence between the radio and optical properties suggests that the outflow is driven by the interaction between the radio jet and the ISM. Despite the high outflow velocities, no evidence is found for the ionisation of the gas being due to fast shocks in the region of the outflow, indicating that photoionisation from the AGN is likely to be the dominant ionisation mechanism. The outflow rate of the warm (ionised) gas is small compared to that of the cold gas. The mass outflow rate associated with the HI is in the same range as for ``mild'' starburst-driven superwinds in ULIRGs. However, in IC5063, the AGN-driven outflow appears to be limited to the inner kpc region of the galaxy. The kinetic power associated with the HI outflow is a small fraction (a few x 10^-4) of the Eddington luminosity of the galaxy but is a significant fraction (~ 0.1) of the nuclear bolometric luminosity. In IC5063, the outflows may have sufficient kinetic power to have a significant impact on the evolution of the ISM in the host galaxy.

R. Morganti; J. Holt; L. Saripalli; T. A. Oosterloo; C. N. Tadhunter

2007-10-05T23:59:59.000Z

149

Estimation of fracture flow parameters through numerical analysis of hydromechanical pressure pulses  

SciTech Connect (OSTI)

The flow parameters of a natural fracture were estimated by modeling in situ pressure pulses. The pulses were generated in two horizontal boreholes spaced 1 m apart vertically and intersecting a near-vertical highly permeable fracture located within a shallow fractured carbonate reservoir. Fracture hydromechanical response was monitored using specialized fiber-optic borehole equipment that could simultaneously measure fluid pressure and fracture displacements. Measurements indicated a significant time lag between the pressure peak at the injection point and the one at the second measuring point, located 1 m away. The pressure pulse dilated and contracted the fracture. Field data were analyzed through hydraulic and coupled hydromechanical simulations using different governing flow laws. In matching the time lag between the pressure peaks at the two measuring points, our hydraulic models indicated that (1) flow was channeled in the fracture, (2) the hydraulic conductivity tensor was highly anisotropic, and (3) the radius of pulse influence was asymmetric, in that the pulse travelled faster vertically than horizontally. Moreover, our parametric study demonstrated that the fluid pressure diffusion through the fracture was quite sensitive to the spacing and orientation of channels, hydraulic aperture, storativity and hydraulic conductivity. Comparison between hydraulic and hydromechanical models showed that the deformation significantly affected fracture permeability and storativity, and consequently, the fluid pressure propagation, suggesting that the simultaneous measurements of pressure and mechanical displacement signals could substantially improve the interpretation of pulse tests during reservoir characterization.

Cappa, F.; Guglielmi, Y.; Rutqvist, J.; Tsang, C.-F.; Thoraval, A.

2008-03-16T23:59:59.000Z

150

Naturally fractured tight gas reservoir detection optimization  

SciTech Connect (OSTI)

Building upon the partitioning of the Greater Green River Basin (GGRB) that was conducted last quarter, the goal of the work this quarter has been to conclude evaluation of the Stratos well and the prototypical Green River Deep partition, and perform the fill resource evaluation of the Upper Cretaceous tight gas play, with the goal of defining target areas of enhanced natural fracturing. The work plan for the quarter of November 1-December 31, 1998 comprised four tasks: (1) Evaluation of the Green River Deep partition and the Stratos well and examination of potential opportunity for expanding the use of E and P technology to low permeability, naturally fractured gas reservoirs, (2) Gas field studies, and (3) Resource analysis of the balance of the partitions.

NONE

1999-06-01T23:59:59.000Z

151

Review article Induced seismicity and hydraulic fracturing for the recovery of  

E-Print Network [OSTI]

of gas and oil from low-permeability sedimentary rocks (M 1.0e3.8). Reactivation of faults and resultant seismicity linked to the hydraulic fracturing of low-permeability sedimentary rocks such as `tight' sandston and magnitudes are (a) mining (M 1.6e5.6); (b) oil and gas field depletion (M 1.0e7.3); (c) water injection

Foulger, G. R.

152

Spatial statistics for predicting flow through a rock fracture  

SciTech Connect (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

153

Bipolar molecular outflows driven by hydromagnetic protostellar winds  

E-Print Network [OSTI]

We demonstrate that magnetically-collimated protostellar winds will sweep ambient material into thin, radiative, momentum-conserving shells whose features reproduce those commonly observed in bipolar molecular outflows. We find the typical position-velocity and mass-velocity relations to occur in outflows in a wide variety of ambient density distributions, regardless of the time histories of their driving winds.

Christopher D. Matzner; Christopher F. McKee

1999-09-29T23:59:59.000Z

154

THE TEMPERATURE DEPENDENCE OF SOLAR ACTIVE REGION OUTFLOWS  

SciTech Connect (OSTI)

Spectroscopic observations with the EUV Imaging Spectrometer (EIS) on Hinode have revealed large areas of high-speed outflows at the periphery of many solar active regions. These outflows are of interest because they may connect to the heliosphere and contribute to the solar wind. In this paper, we use slit rasters from EIS in combination with narrowband slot imaging to study the temperature dependence and morphology of an outflow region and show that it is more complicated than previously thought. Outflows are observed primarily in emission lines from Fe XI to Fe XV. Observations at lower temperatures (Si VII), in contrast, show bright fan-like structures that are dominated by inflows. These data also indicate that the morphology of the outflows and the fans is different, outflows are observed in regions where there is no emission in Si VII. This suggests that the fans, which are often associated with outflows in studies involving imaging data, are not directly related to the active region outflows.

Warren, Harry P.; Ugarte-Urra, Ignacio; Young, Peter R.; Stenborg, Guillermo [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)

2011-01-20T23:59:59.000Z

155

Low-frequency fluid waves in fractures and pipes  

SciTech Connect (OSTI)

Low-frequency analytical solutions have been obtained for phase velocities of symmetrical fluid waves within both an infinite fracture and a pipe filled with a viscous fluid. Three different fluid wave regimes can exist in such objects, depending on the various combinations of parameters, such as fluid density, fluid viscosity, walls shear modulus, channel thickness, and frequency. Equations for velocities of all these regimes have explicit forms and are verified by comparisons with the exact solutions. The dominant role of fractures in rock permeability at field scales and the strong amplitude and frequency effects of Stoneley guided waves suggest the importance of including these wave effects into poroelastic theories.

Korneev, Valeri

2010-09-01T23:59:59.000Z

156

Reconnection outflow generated turbulence in the solar wind  

E-Print Network [OSTI]

Petschek-type time-dependent reconnection (TDR) and quasi-stationary reconnection (QSR) models are considered to understand reconnection outflow structures and the features of the associated locally generated turbulence in the solar wind. We show that the outflow structures, such as discontinuites, Kelvin-Helmholtz (KH) unstable flux tubes or continuous space filling flows cannot be distinguished from one-point WIND measurements. In both models the reconnection outflows can generate more or less spatially extended turbulent boundary layers (TBDs). The structure of an unique extended reconnection outflow is investigated in detail. The analysis of spectral scalings and break locations show that reconnection outflows can control the local field and plasma conditions which may play in favor of one or another turbulent dissipation mechanisms with their characteristic scales and wavenumbers.

Vörös, Z; Semenov, V S; Zaqarashvili, T V; Bruno, R; Khodachenko, M

2014-01-01T23:59:59.000Z

157

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

SciTech Connect (OSTI)

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

158

E-Print Network 3.0 - aqueous outflow facility Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Report* on The Effect of GAGases on Outflow Facility in the Bovine Eye by Mark Johnson1... hyaluronidase increased outflow ... Source: Northwestern University, Dynamics of...

159

The Political History of Hydraulic Fracturing’s Expansion Across the West  

E-Print Network [OSTI]

Political History of Hydraulic Fracturing’s Expansion AcrossPolitical History of Hydraulic Fracturing’s Expansion Acrosss use of the hydraulic fracturing development process.

Forbis, Robert E.

2014-01-01T23:59:59.000Z

160

The evolution of an applied hydraulic fracture project, Frontier Formation Moxa Arch, Wyoming  

SciTech Connect (OSTI)

This paper demonstrates a methodical approach in the implementation of current hydraulic fracturing technologies. Specific examples illustrating the evolution of a consistent reservoir/hydraulic fracturing interpretation are presented in a case history of three GRI-Industry Technology Transfer wells. Detailed modeling of these project wells provided an overall reservoir and hydraulic fracture description that was consistent with respect to all observations. Based on identification of the fracturing mechanisms occurring, the second and third project wells show the capabilities of real-time diagnostics in the implementation of hydraulic fracture treatments. By optimizing the pad volume and fluid integrity to avoid premature screenouts, significant cost savings and improved proppant placement were achieved. The production and pressure build-up response in the first project well verifies the overall interpretation of the reservoir/hydraulic fracture model and provides the basis for eliminating the use of moderate strength/higher cost proppant over sand in low permeability/higher closure stress environments.

Harkrider, J.D.; Aud, W.W.; Cipolla, C.L.; Hansen, J.T.

1994-12-31T23:59:59.000Z

Note: This page contains sample records for the topic "outflow fracture permeability" 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.


161

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

162

Rejuvenating Permeable Reactive Barriers by Chemical Flushing  

Broader source: Energy.gov [DOE]

Final Report:Rejuvenating Permeable Reactive Barriers by Chemical Flushing,U.S. Environmental Protection Agency, Region 8 Support.August 2004

163

A model for changes in coalbed permeability during primary and enhanced methane, recovery  

SciTech Connect (OSTI)

The natural fracture network of a dual-porosity coalbed reservoir is made up of two sets of orthogonal, and usually subvertically oriented, cleats. Coalbed permeability has been shown to vary exponentially with changes in the effective horizontal stress acting across the cleats through the cleat-volume compressibility, which is analogous to pore compressibility in porous rocks. A formulation for changes in the effective horizontal stress of coalbeds during primary methane recovery, which includes a Langmuir type curve shrinkage term, has been proposed previously. This paper presents a new version of the stress formulation by making a direct link between the volumetric matrix strain and the amount of gas desorbed. The resulting permeability model can be extended readily to account for adsorption-induced matrix swelling as well as matrix shrinkage during enhanced methane recovery involving the injection of an inert gas or gas mixture into the seams. The permeability model is validated against a recently published pressure-dependent permeability multiplier curve representative of the San Juan basin coalbeds at post-dewatering production stages. The extended permeability model is then applied successfully to history matching a micropilot test involving the injection of flue gas (consisting mainly of CO{sub 2} and N{sub 2}) at the Fenn Big Valley, Alberta, Canada.

Shi, J.Q.; Durucan, S. [University of London Imperial College of Science Technology & Medicine, London (United Kingdom). Dept. of Environmental Science & Technology

2005-08-01T23:59:59.000Z

164

Evaluation of fracture treatments using a layered-reservoir description: Field examples  

SciTech Connect (OSTI)

This paper presents a practical analysis technique to determine actual fracture geometry and proppant profile using a three-dimensional (3D) hydraulic-fracturing simulator. The hydraulic-fracturing model used in this study considers the variation of in-situ stress, Young`s modulus, Poisson`s ratio, and net pay thickness in the productive interval. When the method is applied, the results from the fracture propagation model conform well with the results the authors obtain from pressure-buildup and production-data analyses. This study analyzed hydraulic-fracturing treatments from several wells in the Vicksburg formation of the McAllen Ranch area in south Texas. The authors have provided guidelines to properly describe the treatment interval, how to use this information in the analysis of such fracture treatments, and how to confirm the results using pressure-transient tests and production-data analyses. This paper presents examples illustrating that a detailed description of the reservoir layers is essential to properly evaluate hydraulic-fracture treatments. For the example wells presented in this paper, post-fracture-production and pressure-transient data were available. The authors have analyzed production and pressure-transient data to estimate permeability and fracture half-length. The values of fracture half-length used to analyze the production data matched closely with those predicted by the fracture model.

Rahim, Z.; Holditch, S.A.; Zuber, M.D. [Holditch and Associates Inc., College Station, TX (United States); Buehring, D.R.

1998-02-01T23:59:59.000Z

165

Upscaling solute transport in naturally fractured porous media with the continuous time random walk method  

SciTech Connect (OSTI)

Solute transport in fractured porous media is typically 'non-Fickian'; that is, it is characterized by early breakthrough and long tailing and by nonlinear growth of the Green function-centered second moment. This behavior is due to the effects of (1) multirate diffusion occurring between the highly permeable fracture network and the low-permeability rock matrix, (2) a wide range of advection rates in the fractures and, possibly, the matrix as well, and (3) a range of path lengths. As a consequence, prediction of solute transport processes at the macroscale represents a formidable challenge. Classical dual-porosity (or mobile-immobile) approaches in conjunction with an advection-dispersion equation and macroscopic dispersivity commonly fail to predict breakthrough of fractured porous media accurately. It was recently demonstrated that the continuous time random walk (CTRW) method can be used as a generalized upscaling approach. Here we extend this work and use results from high-resolution finite element-finite volume-based simulations of solute transport in an outcrop analogue of a naturally fractured reservoir to calibrate the CTRW method by extracting a distribution of retention times. This procedure allows us to predict breakthrough at other model locations accurately and to gain significant insight into the nature of the fracture-matrix interaction in naturally fractured porous reservoirs with geologically realistic fracture geometries.

Geiger, S.; Cortis, A.; Birkholzer, J.T.

2010-04-01T23:59:59.000Z

166

Multiphase Fluid Flow in Deformable Variable-Aperture Fractures - Final Report  

SciTech Connect (OSTI)

Fractures provide flow paths that can potentially lead to fast migration of fluids or contaminants. A number of energy-­?related applications involve fluid injections that significantly perturb both the pressures and chemical composition of subsurface fluids. These perturbations can cause both mechanical deformation and chemical alteration of host rocks with potential for significant changes in permeability. In fractured rock subjected to coupled chemical and mechanical stresses, it can be difficult to predict the sign of permeability changes, let alone the magnitude. This project integrated experimental and computational studies to improve mechanistic understanding of these coupled processes and develop and test predictive models and monitoring techniques. The project involved three major components: (1) study of two-­?phase flow processes involving mass transfer between phases and dissolution of minerals along fracture surfaces (Detwiler et al., 2009; Detwiler, 2010); (2) study of fracture dissolution in fractures subjected to normal stresses using experimental techniques (Ameli, et al., 2013; Elkhoury et al., 2013; Elkhoury et al., 2014) and newly developed computational models (Ameli, et al., 2014); (3) evaluation of electrical resistivity tomography (ERT) as a method to detect and quantify gas leakage through a fractured caprock (Breen et al., 2012; Lochbuhler et al., 2014). The project provided support for one PhD student (Dr. Pasha Ameli; 2009-­?2013) and partially supported a post-­?doctoral scholar (Dr. Jean Elkhoury; 2010-­?2013). In addition, the project provided supplemental funding to support collaboration with Dr. Charles Carrigan at Lawrence Livermore National Laboratory in connection with (3) and supported one MS student (Stephen Breen; 2011-­?2013). Major results from each component of the project include the following: (1) Mineral dissolution in fractures occupied by two fluid phases (e.g., oil-­?water or water-­?CO{sub 2}) causes changes in local capillary forces and redistribution of fluids. These coupled processes enhance channel formation and the potential for development of fast flow paths through fractures. (2) Dissolution in fractures subjected to normal stress can result in behaviors ranging from development of dissolution channels and rapid permeability increases to fracture healing and significant permeability decreases. The timescales associated with advective transport of dissolved ions in the fracture, mineral dissolution rates, and diffusion within the adjacent porous matrix dictate the sign and magnitude of the resulting permeability changes. Furthermore, a high-­? resolution mechanistic model that couples elastic deformation of contacts and aperture-­?dependent dissolution rates predicts the range of observed behaviors reasonably well. (3) ERT has potential as a tool for monitoring gas leakage in deep formations. Using probabilistic inversion methods further enhances the results by providing uncertainty estimates of inverted parameters.

Detwiler, Russell

2014-04-30T23:59:59.000Z

167

CMB Anisotropies from Outflows in Lyman Break Galaxies  

E-Print Network [OSTI]

Thomson scattering of the Cosmic Microwave Background (CMB) on moving electrons in the outflows of Lyman Break Galaxies (LBGs) at redshifts 2-8 contributes to the small-scale CMB anisotropies. The net effect produced by each outflow depends on its level of deviation from spherical symmetry, caused either by an anisotropic energy injection from the nuclear starburst or quasar activity, or by an inhomogeneous intergalactic environment. We find that for plausible outflow parameters consistent with spectroscopic observations of LBGs, the induced CMB anisotropies on arcminute scales reach up to $\\sim 1 \\mu$K, comparable to the level produced during the epoch of reionization.

Daniel Babich; Abraham Loeb

2006-09-14T23:59:59.000Z

168

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, J R; Glaser, Steven D

2007-01-01T23:59:59.000Z

169

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

170

Hydraulic fracture mechanism in unconsolidated formations.  

E-Print Network [OSTI]

??Most models developed for hydraulic fracturing in unconsolidated sands are based on Linear Elastic Fracture Mechanics (LEFM) and tensile fracture (Mode I fracture). However, in… (more)

Hosseini, Seyed Mehran

2012-01-01T23:59:59.000Z

171

The Hydrothermal Outflow Plume of Valles Caldera, New Mexico...  

Open Energy Info (EERE)

Plume of Valles Caldera, New Mexico, and a Comparison with Other Outflow Plumes Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: The Hydrothermal...

172

MISALIGNMENT OF MAGNETIC FIELDS AND OUTFLOWS IN PROTOSTELLAR CORES  

SciTech Connect (OSTI)

We present results of {lambda}1.3 mm dust-polarization observations toward 16 nearby, low-mass protostars, mapped with {approx}2.''5 resolution at CARMA. The results show that magnetic fields in protostellar cores on scales of {approx}1000 AU are not tightly aligned with outflows from the protostars. Rather, the data are consistent with scenarios where outflows and magnetic fields are preferentially misaligned (perpendicular), or where they are randomly aligned. If one assumes that outflows emerge along the rotation axes of circumstellar disks, and that the outflows have not disrupted the fields in the surrounding material, then our results imply that the disks are not aligned with the fields in the cores from which they formed.

Hull, Charles L. H.; Plambeck, Richard L.; Bower, Geoffrey C.; Heiles, Carl; Meredith Hughes, A. [Astronomy Department and Radio Astronomy Laboratory, University of California, Berkeley, CA 94720-3411 (United States); Bolatto, Alberto D.; Jameson, Katherine; Mundy, Lee; Pound, Marc W. [Astronomy Department and Laboratory for Millimeter-wave Astronomy, University of Maryland, College Park, MD 20742 (United States); Carpenter, John M.; Lamb, James W.; Pillai, Thushara [Department of Astronomy, California Institute of Technology, 1200 E. California Blvd., MC 249-17, Pasadena, CA 91125 (United States); Crutcher, Richard M.; Hakobian, Nicholas S.; Kwon, Woojin; Looney, Leslie W. [Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 W Green Street, Urbana, IL 61801 (United States); Fiege, Jason D.; Franzmann, Erica [Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Houde, Martin [Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada); Matthews, Brenda C., E-mail: chat@astro.berkeley.edu [Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Rd., Victoria, BC V8P 5C2 (Canada); and others

2013-05-10T23:59:59.000Z

173

Advection-Dominated Accretion with Infall and Outflows  

E-Print Network [OSTI]

We present self-similar solutions for advection-dominated accretion flows with radial viscous force in the presence of outflows from the accretion flow or infall. The axisymmetric flow is treated in variables integrated over polar sections and the effects of infall and outflows on the accretion flow are parametrised for possible configurations compatible with the self-similar solution. We investigate the resulting accretion flows for three different viscosity laws and derive upper limits on the viscosity parameter alpha. In addition, we find a natural connection to non-rotating and spherical accretion with turbulent viscosity, which is assumed to persist even without differential rotation. Positive Bernoulli numbers for advection-dominated accretion allow a fraction of the gas to be expelled in an outflow and the upper limit on the viscosity predicts that outflows are inevitable for equations of state close to an ideal gas.

Thomas Beckert

2000-03-22T23:59:59.000Z

174

HOT ELECTROMAGNETIC OUTFLOWS. II. JET BREAKOUT  

SciTech Connect (OSTI)

We consider the interaction between radiation, matter, and a magnetic field in a compact, relativistic jet. The entrained matter accelerates outward as the jet breaks out of a star or other confining medium. In some circumstances, such as gamma-ray bursts (GRBs), the magnetization of the jet is greatly reduced by an advected radiation field while the jet is optically thick to scattering. Where magnetic flux surfaces diverge rapidly, a strong outward Lorentz force develops and radiation and matter begin to decouple. The increase in magnetization is coupled to a rapid growth in Lorentz factor. We take two approaches to this problem. The first examines the flow outside the fast magnetosonic critical surface, and calculates the flow speed and the angular distribution of the radiation field over a range of scattering depths. The second considers the flow structure on both sides of the critical surface in the optically thin regime, using a relaxation method. In both approaches, we find how the terminal Lorentz factor and radial profile of the outflow depend on the radiation intensity and optical depth at breakout. The effect of bulk Compton scattering on the radiation spectrum is calculated by a Monte Carlo method, while neglecting the effects of internal dissipation. The peak of the scattered spectrum sits near the seed peak if radiation pressure dominates the acceleration, but is pushed to a higher frequency if the Lorentz force dominates. The unscattered seed radiation can form a distinct, low-frequency component of the spectrum, especially if the magnetic Poynting flux dominates.

Russo, Matthew [Department of Physics, University of Toronto, 60 St. George Street, Toronto, ON M5S 1A7 (Canada); Thompson, Christopher [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, Toronto, ON M5S 3H8 (Canada)

2013-08-20T23:59:59.000Z

175

Simulation of Hydraulic Fractures and their Interactions with Natural Fractures  

E-Print Network [OSTI]

Modeling the stimulated reservoir volume during hydraulic fracturing is important to geothermal and petroleum reservoir stimulation. The interaction between a hydraulic fracture and pre-existing natural fractures exerts significant control...

Sesetty, Varahanaresh

2012-10-19T23:59:59.000Z

176

Ultra-fast outflows (aka UFOs) from AGNs and QSOs  

E-Print Network [OSTI]

During the last decade, strong observational evidence has been accumulated for the existence of massive, high velocity winds/outflows (aka Ultra Fast Outflows, UFOs) in nearby AGNs and in more distant quasars. Here we briefly review some of the most recent developments in this field and discuss the relevance of UFOs for both understanding the physics of accretion disk winds in AGNs, and for quantifying the global amount of AGN feedback on the surrounding medium.

Cappi, M; Giustini, M

2013-01-01T23:59:59.000Z

177

State-of-the-art fracturing in the North Sea  

SciTech Connect (OSTI)

This paper will focus on recent advances in hydraulic fracturing technology with emphasis on North Sea applications. Five generalized applications that will benefit most from advances in technology have been identified. Because North Sea oil and gas field development requires the use of platform facilities for wellhead and processing equipment, deviated and horizontal wells are often used to effectively drain the reservoirs. Many of these wells require fracture stimulation. The success rate of such wells has increased significantly in recent years as a result of the following: Researchers better understand how fractures initiate and grow; Pre-treatment diagnostic techniques have improved substantially; Engineers better understand how completion design affects well performance. With improved understanding of post-frac well performance, engineers can evaluate the feasibility of developing a reservoir through fractured, horizontal wells. In addition to a review of the advances in HPHT technology that would apply to North Sea applications, this paper will identify improvements necessary before these techniques are applied in the North Sea. Hydraulic fracturing is being used more frequently (1) in high-permeability reservoirs to improve the overall profitability of the project, and (2) as an alternative to traditional sand control applications in soft, weakly consolidated reservoirs. The effect of hydraulic fracturing operations on the North Sea environment must be recognized. The advances in fluid design and post-treatment flowback procedures that minimize these effects are discussed. 78 refs., 19 figs.

Domelen, M.S. Van; Jacquier, R.C.; Sanders, M.W.

1995-12-31T23:59:59.000Z

178

Slow Waves in Fractures Filled with Viscous Fluid  

SciTech Connect (OSTI)

Stoneley guided waves in a fluid-filled fracture generally have larger amplitudes than other waves, and therefore, their properties need to be incorporated in more realistic models. In this study, a fracture is modeled as an infinite layer of viscous fluid bounded by two elastic half-spaces with identical parameters. For small fracture thickness, I obtain a simple dispersion equation for wave-propagation velocity. This velocity is much smaller than the velocity of a fluid wave in a Biot-type solution, in which fracture walls are assumed to be rigid. At seismic prospecting frequencies and realistic fracture thicknesses, the Stoneley guided wave has wavelengths on the order of several meters and an attenuation Q factor exceeding 10, which indicates the possibility of resonance excitation in fluid-bearing rocks. The velocity and attenuation of Stoneley guided waves are distinctly different at low frequencies for water and oil. The predominant role of fractures in fluid flow at field scales is supported by permeability data showing an increase of several orders of magnitude when compared to values obtained at laboratory scales. These data suggest that Stoneley guided waves should be taken into account in theories describing seismic wave propagation in fluid-saturated rocks.

Korneev, Valeri

2008-01-08T23:59:59.000Z

179

Changes in seal capacity of fractured claystone caprocks induced by dissolved and gaseous CO2 seepage  

E-Print Network [OSTI]

Changes in seal capacity of fractured claystone caprocks induced by dissolved and gaseous CO2; accepted 17 June 2008; published 31 July 2008. [1] Claystone caprocks are often the ultimate seal for CO2 underground storage when residual CO2 gas reaches the reservoir top due to buoyancy. Permeability changes

Luquot, Linda

180

Dominant Nuclear Outflow Driving Mechanisms in Powerful Radio Galaxies  

E-Print Network [OSTI]

In order to identify the dominant nuclear outflow mechanisms in Active Galactic Nuclei, we have undertaken deep, high resolution observations of two compact radio sources (PKS 1549-79 and PKS 1345+12) with the Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope. Not only are these targets known to have powerful emission line outflows, but they also contain all the potential drivers for the outflows: relativistic jets, quasar nuclei and starbursts. ACS allows the compact nature (nuclear position angles of both the optical emission line and radio data. There is no evidence for bi-conical emission line features on the large-scale and there is a divergance in the relative position angles of the optical and radio structure. This enables us to exclude starburst driven outflows. However, we are unable to clearly distinguish between radiative AGN wind driven outflows and outflows powered by relativistic radio jets. The small scale bi-conical features, indicative of such mechanisms could be below the resolution limit of ACS, especially if aligned close to the line of sight. In addition, there may be offsets between the radio and optical nuclei induced by heavy dust obscuration, nebular continuum or scattered light from the AGN.

Dan Batcheldor; Clive Tadhunter; Joanna Holt; Raffaella Morganti; Christopher P. O'Dea; David J. Axon; Anton Koekemoer

2007-02-20T23:59:59.000Z

Note: This page contains sample records for the topic "outflow fracture permeability" 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

ADVANCED FRACTURING TECHNOLOGY FOR TIGHT GAS: AN EAST TEXAS FIELD DEMONSTRATION  

SciTech Connect (OSTI)

The primary objective of this research was to improve completion and fracturing practices in gas reservoirs in marginal plays in the continental United States. The Bossier Play in East Texas, a very active tight gas play, was chosen as the site to develop and test the new strategies for completion and fracturing. Figure 1 provides a general location map for the Dowdy Ranch Field, where the wells involved in this study are located. The Bossier and other tight gas formations in the continental Unites States are marginal plays in that they become uneconomical at gas prices below $2.00 MCF. It was, therefore, imperative that completion and fracturing practices be optimized so that these gas wells remain economically attractive. The economic viability of this play is strongly dependent on the cost and effectiveness of the hydraulic fracturing used in its well completions. Water-fracs consisting of proppant pumped with un-gelled fluid is the type of stimulation used in many low permeability reservoirs in East Texas and throughout the United States. The use of low viscosity Newtonian fluids allows the creation of long narrow fractures in the reservoir, without the excessive height growth that is often seen with cross-linked fluids. These low viscosity fluids have poor proppant transport properties. Pressure transient tests run on several wells that have been water-fractured indicate a long effective fracture length with very low fracture conductivity even when large amounts of proppant are placed in the formation. A modification to the water-frac stimulation design was needed to transport proppant farther out into the fracture. This requires suspending the proppant until the fracture closes without generating excessive fracture height. A review of fracture diagnostic data collected from various wells in different areas (for conventional gel and water-fracs) suggests that effective propped lengths for the fracture treatments are sometimes significantly shorter than those predicted by fracture models. There was no accepted optimal method for conducting hydraulic fracturing in the Bossier. Each operator used a different approach. Anadarko, the most active operator in the play, had tested at least four different kinds of fracture treatments. The ability to arrive at an optimal fracturing program was constrained by the lack of adequate fracture models to simulate the fracturing treatment, and an inability to completely understand the results obtained in previous fracturing programs. This research aimed at a combined theoretical, experimental and field-testing program to improve fracturing practices in the Bossier and other tight gas plays.

Mukul M. Sharma

2005-03-01T23:59:59.000Z

182

TEMPORAL VARIATIONS OF FRACTURE DIRECTIONS AND FRACTURE DENSITIES...  

Open Energy Info (EERE)

TEMPORAL VARIATIONS OF FRACTURE DIRECTIONS AND FRACTURE DENSITIES IN THE COSO GEOTHERMAL FIELD FROM ANALYSES OF SHEAR-WAVE SPLITTING Jump to: navigation, search OpenEI Reference...

183

Multiple-point statistical prediction on fracture networks at Yucca Mountain  

SciTech Connect (OSTI)

In many underground nuclear waste repository systems, such as at Yucca Mountain, water flow rate and amount of water seepage into the waste emplacement drifts are mainly determined by hydrological properties of fracture network in the surrounding rock mass. Natural fracture network system is not easy to describe, especially with respect to its connectivity which is critically important for simulating the water flow field. In this paper, we introduced a new method for fracture network description and prediction, termed multi-point-statistics (MPS). The process of the MPS method is to record multiple-point statistics concerning the connectivity patterns of a fracture network from a known fracture map, and to reproduce multiple-scale training fracture patterns in a stochastic manner, implicitly and directly. It is applied to fracture data to study flow field behavior at the Yucca Mountain waste repository system. First, the MPS method is used to create a fracture network with an original fracture training image from Yucca Mountain dataset. After we adopt a harmonic and arithmetic average method to upscale the permeability to a coarse grid, THM simulation is carried out to study near-field water flow in the surrounding waste emplacement drifts. Our study shows that connectivity or patterns of fracture networks can be grasped and reconstructed by MPS methods. In theory, it will lead to better prediction of fracture system characteristics and flow behavior. Meanwhile, we can obtain variance from flow field, which gives us a way to quantify model uncertainty even in complicated coupled THM simulations. It indicates that MPS can potentially characterize and reconstruct natural fracture networks in a fractured rock mass with advantages of quantifying connectivity of fracture system and its simulation uncertainty simultaneously.

Liu, X.Y; Zhang, C.Y.; Liu, Q.S.; Birkholzer, J.T.

2009-05-01T23:59:59.000Z

184

A Rare Isolated Trapezoid Fracture  

E-Print Network [OSTI]

wrist in suggested scaphoid fracture. Acta Radiol. 1988;29:Rare isolated trapezoid fracture: a case report. Hand. 2008;suspect and diagnose this fracture. 2,8 REFERENCES 1. Papp

Afifi, Negean; Lu, Jenny J

2011-01-01T23:59:59.000Z

185

Experimental and Theoretical Investigation of Multiphase Flow in Fractured Porous media, SUPRI TR-116, Topical Report  

SciTech Connect (OSTI)

The fluid transfer parameters between rock matrix and fracture are not well known. Consequently, simulation of fractured reservoirs uses, in general, very crude and unproven hypotheses such as zero capillary pressure in the fracture and/or relative permeability linear with saturation. In order to improve the understanding of flow in fractured media, an experimental study was conducted and numerical simulations of the experiments were made. A laboratory flow apparatus was built to obtain data on water- air imbibition and oil-water drainage displacements in horizontal single-fractured block systems. For this purpose, two configurations have been used: a two-block system with a 1 mm spacer between the blocks, and a two-block system with no spacer. During the experiments, porosity and saturation measurements along the cores have been made utilizing an X-ray Computerized Tomography (CT) scanner. Saturation images were reconstructed in 3-D to observe matrix-fracture interactions. Differences in fluid saturations and relative permeabilities caused by changes in fracture width have also been analyzed.

Akin, Serhat; Castanier, Louis M.; German, Edgar Rene Rangel

1999-08-09T23:59:59.000Z

186

Hydrogen permeability and Integrity of hydrogen transfer pipelines...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

permeability and Integrity of hydrogen transfer pipelines Hydrogen permeability and Integrity of hydrogen transfer pipelines Presentation by 03-Babu for the DOE Hydrogen Pipeline...

187

Hydrogen Permeability and Integrity of Hydrogen Delivery Pipelines...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Permeability and Integrity of Hydrogen Delivery Pipelines Hydrogen Permeability and Integrity of Hydrogen Delivery Pipelines Project Objectives: To gain basic understanding of...

188

Secondary porosity and permeability of coal vs. gas composition and pressure  

SciTech Connect (OSTI)

We have been investigating the sequestration of atmospheric pollutants by injection into coal seams while at the same time enhancing hydrocarbon productivity by displacement of methane with pollutants. We found that changing the composition of the gas sorbed into the coal changes the porosity and permeability of the coal natural-fracture system owing to gas-content changes, which cause matrix swelling or shrinkage due to relative adsorption of different gases. We collected sufficient information to develop a method for predicting the permeability and porosity of a coalbed as a function of the secondary porosity system (SPS) pressure and the gas content and composition of the primary porosity system (PPS). The method uses data from injection/falloff tests with water and/or a weaker adsorbing gas (WAG) than CH{sub 4} and a stronger adsorbing gas (SAG) than CH{sub 4}. Estimates of effective permeability to gas and water obtained from these tests are used with an iterative computation procedure subject to constraints to solve for equivalent SPS porosity and absolute permeability at atmospheric pressure. Once calibrated, the model can be used to predict a coalbed's permeability and porosity as a function of injection pressure and injected-fluid composition, which in turn are used to predict injection performance. The model is applicable to production forecasts to account for SPS permeability and porosity changes as reservoir pressure declines with changes in gas composition. This paper describes the new model and discusses well-test procedures to obtain the data required for model calibration. Also included are coal property estimates resulting from Alberta Medicine River (Manville) coal core and test data and an example model calibration.

Mavor, M.J,; Gunter, W.D. [Tesseract Corp., San Francisco, CA (United States)

2006-04-15T23:59:59.000Z

189

Test plan: Hydraulic fracturing and hydrologic tests in Marker Beds 139 and 140  

SciTech Connect (OSTI)

Combined hydraulic fracturing and hydrological measurements in this test plan are designed to evaluate the potential influence of fracture formation in anhydrite Marker Beds 139 and 140 on gas pressure in and gas flow from the disposal rooms in the Waste Isolation Pilot Plant with time. The tests have the further purpose of providing comparisons of permeabilities of anhydrite interbeds in an undisturbed (virgin) state and after fracture development and/or opening and dilation of preexisting partially healed fractures. Three sets of combined hydraulic fracturing and hydrological measurements are planned. A set of trial measurements is expected to last four to six weeks. The duration of each subsequent experiment is anticipated to be six to eight weeks.

Wawersik, W.R.; Beauheim, R.L.

1991-03-01T23:59:59.000Z

190

DEVELOPMENT OF RESERVOIR CHARACTERIZATION TECHNIQUES AND PRODUCTION MODELS FOR EXPLOITING NATURALLY FRACTURED RESERVOIRS  

SciTech Connect (OSTI)

For many years, geoscientists and engineers have undertaken research to characterize naturally fractured reservoirs. Geoscientists have focused on understanding the process of fracturing and the subsequent measurement and description of fracture characteristics. Engineers have concentrated on the fluid flow behavior in the fracture-porous media system and the development of models to predict the hydrocarbon production from these complex systems. This research attempts to integrate these two complementary views to develop a quantitative reservoir characterization methodology and flow performance model for naturally fractured reservoirs. The research has focused on estimating naturally fractured reservoir properties from seismic data, predicting fracture characteristics from well logs, and developing a naturally fractured reservoir simulator. It is important to develop techniques that can be applied to estimate the important parameters in predicting the performance of naturally fractured reservoirs. This project proposes a method to relate seismic properties to the elastic compliance and permeability of the reservoir based upon a sugar cube model. In addition, methods are presented to use conventional well logs to estimate localized fracture information for reservoir characterization purposes. The ability to estimate fracture information from conventional well logs is very important in older wells where data are often limited. Finally, a desktop naturally fractured reservoir simulator has been developed for the purpose of predicting the performance of these complex reservoirs. The simulator incorporates vertical and horizontal wellbore models, methods to handle matrix to fracture fluid transfer, and fracture permeability tensors. This research project has developed methods to characterize and study the performance of naturally fractured reservoirs that integrate geoscience and engineering data. This is an important step in developing exploitation strategies for optimizing the recovery from naturally fractured reservoir systems. The next logical extension of this work is to apply the proposed methods to an actual field case study to provide information for verification and modification of the techniques and simulator. This report provides the details of the proposed techniques and summarizes the activities undertaken during the course of this project. Technology transfer activities were highlighted by a two-day technical conference held in Oklahoma City in June 2002. This conference attracted over 90 participants and included the presentation of seventeen technical papers from researchers throughout the United States.

Michael L. Wiggins; Raymon L. Brown; Faruk Civan; Richard G. Hughes

2002-12-31T23:59:59.000Z

191

Core analysis in a low permeability sandstone reservoir: Results from the Multiwell Experiment  

SciTech Connect (OSTI)

Over 4100 ft (1100 ft oriented) of Mesaverde core was taken during the drilling of the three Multiwell Experiment (MWX) wells, for study in a comprehensive core analysis program. This core traversed five separate depositional environments (shoreline/marine, coastal, paludal, fluvial, and paralic), and almost every major sand in the Mesaverde at the site was sampled. This paper summarizes MWX core analysis and describes the petrophysical properties at the MWX site; reservoir parameters, including permeabilities of naturally fractured core; and mechanical rock properties including stress-related measurements. Some correlations are made between reservoir properties and mineralogy/petrology data. Comparisons are made between the properties of lenticular and blanket sandstone morphologies existing at the site. This paper provides an overview of a complete core analysis in a low-permeability sandstone reservoir. 66 refs., 17 figs. , 9 tabs.

Sattler, A.R.

1989-04-01T23:59:59.000Z

192

Outflows and Jets from Collapsing Magnetized Cloud Cores  

E-Print Network [OSTI]

Star formation is usually accompanied by outflow phenomena. There is strong evidence that these outflows and jets are launched from the protostellar disk by magneto-rotational processes. Here, we report on our three dimensional, adaptive mesh, magneto-hydrodynamic simulations of collapsing, rotating, magnetized Bonnor-Ebert-Spheres whose properties are taken directly from observations. In contrast to the pure hydro case where no outflows are seen, our present simulations show an outflow from the protodisk surface at ~ AU and a jet at ~ 0.07 AU after a strong toroidal magnetic field build up. The large scale outflow, which extends up to ~ AU at the end of our simulation, is driven by toroidal magnetic pressure (spring), whereas the jet is powered by magneto-centrifugal force (fling). At the final stage of our simulation these winds are still confined within two respective shock fronts. Furthermore, we find that the jet-wind and the disk-anchored magnetic field extracts a considerable amount of angular momentum from the protostellar disk. The initial spin of our cloud core was chosen high enough to produce a binary system. We indeed find a close binary system (separation ~ 3 R_sol) which results from the fragmentation of an earlier formed ring structure. The magnetic field strength in these protostars reaches ~ 3 kG and becomes about 3 G at 1 AU from the center in agreement with recent observational results.

Robi Banerjee; Ralph E. Pudritz

2005-12-13T23:59:59.000Z

193

Design and Implementation of Energized Fracture Treatment in Tight Gas Sands  

SciTech Connect (OSTI)

Hydraulic fracturing is essential for producing gas and oil at an economic rate from low permeability sands. Most fracturing treatments use water and polymers with a gelling agent as a fracturing fluid. The water is held in the small pore spaces by capillary pressure and is not recovered when drawdown pressures are low. The un-recovered water leaves a water saturated zone around the fracture face that stops the flow of gas into the fracture. This is a particularly acute problem in low permeability formations where capillary pressures are high. Depletion (lower reservoir pressures) causes a limitation on the drawdown pressure that can be applied. A hydraulic fracturing process can be energized by the addition of a compressible, sometimes soluble, gas phase into the treatment fluid. When the well is produced, the energized fluid expands and gas comes out of solution. Energizing the fluid creates high gas saturation in the invaded zone, thereby facilitating gas flowback. A new compositional hydraulic fracturing model has been created (EFRAC). This is the first model to include changes in composition, temperature, and phase behavior of the fluid inside the fracture. An equation of state is used to evaluate the phase behavior of the fluid. These compositional effects are coupled with the fluid rheology, proppant transport, and mechanics of fracture growth to create a general model for fracture creation when energized fluids are used. In addition to the fracture propagation model, we have also introduced another new model for hydraulically fractured well productivity. This is the first and only model that takes into account both finite fracture conductivity and damage in the invaded zone in a simple analytical way. EFRAC was successfully used to simulate several fracture treatments in a gas field in South Texas. Based on production estimates, energized fluids may be required when drawdown pressures are smaller than the capillary forces in the formation. For this field, the minimum CO{sub 2} gas quality (volume % of gas) recommended is 30% for moderate differences between fracture and reservoir pressures (2900 psi reservoir, 5300 psi fracture). The minimum quality is reduced to 20% when the difference between pressures is larger, resulting in additional gas expansion in the invaded zone. Inlet fluid temperature, flow rate, and base viscosity did not have a large impact on fracture production. Finally, every stage of the fracturing treatment should be energized with a gas component to ensure high gas saturation in the invaded zone. A second, more general, sensitivity study was conducted. Simulations show that CO{sub 2} outperforms N{sub 2} as a fluid component because it has higher solubility in water at fracturing temperatures and pressures. In fact, all gas components with higher solubility in water will increase the fluid's ability to reduce damage in the invaded zone. Adding methanol to the fracturing solution can increase the solubility of CO{sub 2}. N{sub 2} should only be used if the gas leaks-off either during the creation of the fracture or during closure, resulting in gas going into the invaded zone. Experimental data is needed to determine if the gas phase leaks-off during the creation of the fracture. Simulations show that the bubbles in a fluid traveling across the face of a porous medium are not likely to attach to the surface of the rock, the filter cake, or penetrate far into the porous medium. In summary, this research has created the first compositional fracturing simulator, a useful tool to aid in energized fracture design. We have made several important and original conclusions about the best practices when using energized fluids in tight gas sands. The models and tools presented here may be used in the future to predict behavior of any multi-phase or multi-component fracturing fluid system.

Mukul Sharma; Kyle Friehauf

2009-12-31T23:59:59.000Z

194

Massive hydraulic fracture test Cotton Valley Lime East Texas. Final report, 8 August 1978-31 July 1980  

SciTech Connect (OSTI)

This report summarizes the results of an active stimulation program on the Cotton Valley Lime as evaluated using reservoir production and pressure transient data. Using standard economic parameters and reservoir permeabilities determined by history matching, a detailed study was made to determine the well spacing and fracture length radius necessary for optimum development of the Fallon and North Personville Fields. In addition, the major details of designing and executing a super massive hydraulic fracture job are discussed in the appendix.

Kozik, H.G.; Holditch, S.A.; Kumar, A.

1980-08-01T23:59:59.000Z

195

Determination of Transport Properties From Flowing Fluid Temperature LoggingIn Unsaturated Fractured Rocks: Theory And Semi-Analytical Solution  

SciTech Connect (OSTI)

Flowing fluid temperature logging (FFTL) has been recently proposed as a method to locate flowing fractures. We argue that FFTL, backed up by data from high-precision distributed temperature sensors, can be a useful tool in locating flowing fractures and in estimating the transport properties of unsaturated fractured rocks. We have developed the theoretical background needed to analyze data from FFTL. In this paper, we present a simplified conceptualization of FFTL in unsaturated fractured rock, and develop a semianalytical solution for spatial and temporal variations of pressure and temperature inside a borehole in response to an applied perturbation (pumping of air from the borehole). We compare the semi-analytical solution with predictions from the TOUGH2 numerical simulator. Based on the semi-analytical solution, we propose a method to estimate the permeability of the fracture continuum surrounding the borehole. Using this proposed method, we estimated the effective fracture continuum permeability of the unsaturated rock hosting the Drift Scale Test (DST) at Yucca Mountain, Nevada. Our estimate compares well with previous independent estimates for fracture permeability of the DST host rock. The conceptual model of FFTL presented in this paper is based on the assumptions of single-phase flow, convection-only heat transfer, and negligible change in system state of the rock formation. In a sequel paper [Mukhopadhyay et al., 2008], we extend the conceptual model to evaluate some of these assumptions. We also perform inverse modeling of FFTL data to estimate, in addition to permeability, other transport parameters (such as porosity and thermal conductivity) of unsaturated fractured rocks.

Mukhopadhyay, Sumit; Tsang, Yvonne W.

2008-08-01T23:59:59.000Z

196

INVESTIGATION OF EFFICIENCY IMPROVEMENTS DURING CO2 INJECTION IN HYDRAULICALLY AND NATURALLY FRACTURED RESERVOIRS  

SciTech Connect (OSTI)

The objective of this project is to perform unique laboratory experiments with artificial fractured cores (AFCs) and X-ray CT to examine the physical mechanisms of bypassing in HFR and NFR that eventually result in less efficient CO{sub 2} flooding in heterogeneous or fracture-dominated reservoirs. This report provides results of the second semi-annual technical progress report that consists of three different topics. In the first topic, laboratory experiments were performed on a Berea core to investigate the changes in rock properties and fluid flow under different stress-state conditions. A comparative study of different stress conditions was also conducted to analyze the effect of the various loading systems. The experimental results show that fracture permeability reduces significantly as the stress increases compared to matrix permeability. The hydrostatic and triaxial stresses have greater impacts on permeability reduction compared to applying stress in the uniaxial stress condition. Fracture flow dominates when the applied stress is less, however, the matrix flow rate increases as applied stress increases and dominates at high stress even if the fracture does not heal completely. In the second topic, the preliminary results of static imbibition experiments are presented as a precursor to image the saturation profiles using X-Ray CT scanner. The static and dynamic imbibition experiments have been done previously (Schechter et al, 2002). The imaging of imbibition experiment is underway to track the saturation profiles using X-ray CT scanner. Hence, no more conclusions are drawn from this study at this time. In the last topic, the modeling of fluid flow through a single fracture incorporating the effect of surface roughness is conducted. Fracture permeability is usually estimated by a cubic law that is based on the theory of hydrodynamics for the laminar flow between flat plates. However, the cubic law is too simple to estimate the fracture permeability correctly, because the surface of real fracture is much more complicated and rougher than the surface of flat plate. Several researchers have shown that the flow characteristics of an actual fracture surface would be quite different due to the effect of tortuosity, impact of surface roughness and contact areas. Nonetheless, to date, these efforts have not converged to form a unified definition on the fracture aperture needed in the cubic law. In this study, therefore, we show that the cubic law could still be used to model small-scale and field-scale data as long as it is modeled effectively, accounting for the effect of surface roughness associated with the fracture surface. The goal of this research is to examine the effect of surface roughness for flow through fractures and to effectively incorporate them into simulations with the aid of geostatistics. Since the research has been supported with experimental results, the consistency of the results enabled us to define a methodology for single fracture simulation. This methodology successfully modeled the slow rate and pressure drop from fractured core experiments, which were earlier not possible through parallel plate approach. Observations suggest that the fracture aperture needs to be distributed to accurately model the experimental results. The effect of friction and tortuosity due to surface roughness needs to be taken into account while modeling.

David S. Schechter

2002-10-30T23:59:59.000Z

197

Magnetic Reconnection with Asymmetry in the Outflow Direction  

E-Print Network [OSTI]

Magnetic reconnection with asymmetry in the outflow direction occurs in the Earth's magnetotail, coronal mass ejections, flux cancellation events, astrophysical disks, spheromak merging experiments, and elsewhere in nature and the laboratory. A control volume analysis is performed for the case of steady antiparallel magnetic reconnection with asymmetric downstream pressure, which is used to derive scaling relations for the outflow velocity from each side of the current sheet and the reconnection rate. Simple relationships for outflow velocity are presented for the incompressible case and the case of symmetric downstream pressure but asymmetric downstream density. Asymmetry alone is not found to greatly affect the reconnection rate. The flow stagnation point and magnetic field null do not coincide in a steady state unless the pressure gradient is negligible at the flow stagnation point.

Murphy, N A; Cassak, P A

2009-01-01T23:59:59.000Z

198

CORONAL MASS EJECTION INDUCED OUTFLOWS OBSERVED WITH HINODE/EIS  

SciTech Connect (OSTI)

We investigate the outflows associated with two halo coronal mass ejections (CMEs) that occurred on 2006 December 13 and 14 in NOAA 10930, using the Hinode/EIS observations. Each CME was accompanied by an EIT wave and coronal dimmings. Dopplergrams in the dimming regions are obtained from the spectra of seven EIS lines. The results show that strong outflows are visible in the dimming regions during the CME eruption at different heights from the lower transition region to the corona. It is found that the velocity is positively correlated with the photospheric magnetic field, as well as the magnitude of the dimming. We estimate the mass loss based on height-dependent EUV dimmings and find it to be smaller than the CME mass derived from white-light observations. The mass difference is attributed partly to the uncertain atmospheric model, and partly to the transition region outflows, which refill the coronal dimmings.

Jin, M.; Ding, M. D.; Chen, P. F.; Fang, C. [Department of Astronomy, Nanjing University, Nanjing 210093 (China); Imada, S. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)], E-mail: dmd@nju.edu.cn, E-mail: shinsuke.imada@nao.ac.jp

2009-09-01T23:59:59.000Z

199

OPTIMIZATION OF INFILL DRILLING IN NATURALLY-FRACTURED TIGHT-GAS RESERVOIRS  

SciTech Connect (OSTI)

A major goal of industry and the U.S. Department of Energy (DOE) fossil energy program is to increase gas reserves in tight-gas reservoirs. Infill drilling and hydraulic fracture stimulation in these reservoirs are important reservoir management strategies to increase production and reserves. Phase II of this DOE/cooperative industry project focused on optimization of infill drilling and evaluation of hydraulic fracturing in naturally-fractured tight-gas reservoirs. The cooperative project involved multidisciplinary reservoir characterization and simulation studies to determine infill well potential in the Mesaverde and Dakota sandstone formations at selected areas in the San Juan Basin of northwestern New Mexico. This work used the methodology and approach developed in Phase I. Integrated reservoir description and hydraulic fracture treatment analyses were also conducted in the Pecos Slope Abo tight-gas reservoir in southeastern New Mexico and the Lewis Shale in the San Juan Basin. This study has demonstrated a methodology to (1) describe reservoir heterogeneities and natural fracture systems, (2) determine reservoir permeability and permeability anisotropy, (3) define the elliptical drainage area and recoverable gas for existing wells, (4) determine the optimal location and number of new in-fill wells to maximize economic recovery, (5) forecast the increase in total cumulative gas production from infill drilling, and (6) evaluate hydraulic fracture simulation treatments and their impact on well drainage area and infill well potential. Industry partners during the course of this five-year project included BP, Burlington Resources, ConocoPhillips, and Williams.

Lawrence W. Teufel; Her-Yuan Chen; Thomas W. Engler; Bruce Hart

2004-05-01T23:59:59.000Z

200

Continuous time random walk analysis of solute transport in fractured porous media  

SciTech Connect (OSTI)

The objective of this work is to discuss solute transport phenomena in fractured porous media, where the macroscopic transport of contaminants in the highly permeable interconnected fractures can be strongly affected by solute exchange with the porous rock matrix. We are interested in a wide range of rock types, with matrix hydraulic conductivities varying from almost impermeable (e.g., granites) to somewhat permeable (e.g., porous sandstones). In the first case, molecular diffusion is the only transport process causing the transfer of contaminants between the fractures and the matrix blocks. In the second case, additional solute transfer occurs as a result of a combination of advective and dispersive transport mechanisms, with considerable impact on the macroscopic transport behavior. We start our study by conducting numerical tracer experiments employing a discrete (microscopic) representation of fractures and matrix. Using the discrete simulations as a surrogate for the 'correct' transport behavior, we then evaluate the accuracy of macroscopic (continuum) approaches in comparison with the discrete results. However, instead of using dual-continuum models, which are quite often used to account for this type of heterogeneity, we develop a macroscopic model based on the Continuous Time Random Walk (CTRW) framework, which characterizes the interaction between the fractured and porous rock domains by using a probability distribution function of residence times. A parametric study of how CTRW parameters evolve is presented, describing transport as a function of the hydraulic conductivity ratio between fractured and porous domains.

Cortis, Andrea; Cortis, Andrea; Birkholzer, Jens

2008-06-01T23:59:59.000Z

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201

Suspensions in hydraulic fracturing  

SciTech Connect (OSTI)

Suspensions or slurries are widely used in well stimulation and hydraulic fracturing processes to enhance the production of oil and gas from the underground hydrocarbon-bearing formation. The success of these processes depends significantly upon having a thorough understanding of the behavior of suspensions used. Therefore, the characterization of suspensions under realistic conditions, for their rheological and hydraulic properties, is very important. This chapter deals with the state-of-the-art hydraulic fracturing suspension technology. Specifically it deals with various types of suspensions used in well stimulation and fracturing processes, their rheological characterization and hydraulic properties, behavior of suspensions in horizontal wells, review of proppant settling velocity and proppant transport in the fracture, and presently available measurement techniques for suspensions and their merits. Future industry needs for better understanding of the complex behavior of suspensions are also addressed. 74 refs., 21 figs., 1 tab.

Shah, S.N. [Univ. of Oklahoma, Norman, OK (United States)

1996-12-31T23:59:59.000Z

202

SUPERNOVAE AND AGN DRIVEN GALACTIC OUTFLOWS  

SciTech Connect (OSTI)

We present analytical solutions for winds from galaxies with a Navarro-Frank-White (NFW) dark matter halo. We consider winds driven by energy and mass injection from multiple supernovae (SNe), as well as momentum injection due to radiation from a central black hole. We find that the wind dynamics depends on three velocity scales: (1) v{sub *}{approx}( E-dot / 2 M-dot ){sup 1/2} describes the effect of starburst activity, with E-dot and M-dot as energy and mass injection rate in a central region of radius R; (2) v {sub .} {approx} (GM {sub .}/2R){sup 1/2} for the effect of a central black hole of mass M {sub .} on gas at distance R; and (3) v{sub s}=(GM{sub h} / 2Cr{sub s}){sup 1/2}, which is closely related to the circular speed (v{sub c} ) for an NFW halo, where r{sub s} is the halo scale radius and C is a function of the halo concentration parameter. Our generalized formalism, in which we treat both energy and momentum injection from starbursts and radiation from the central active galactic nucleus (AGN), allows us to estimate the wind terminal speed to be (4v {sup 2} {sub *} + 6({Gamma} - 1)v {sub .} {sup 2} - 4v {sup 2} {sub s}){sup 1/2}, where {Gamma} is the ratio of force due to radiation pressure to gravity of the central black hole. Our dynamical model also predicts the following: (1) winds from quiescent star-forming galaxies cannot escape from 10{sup 11.5} M {sub Sun} {<=} M{sub h} {<=} 10{sup 12.5} M {sub Sun} galaxies; (2) circumgalactic gas at large distances from galaxies should be present for galaxies in this mass range; (3) for an escaping wind, the wind speed in low- to intermediate-mass galaxies is {approx}400-1000 km s{sup -1}, consistent with observed X-ray temperatures; and (4) winds from massive galaxies with AGNs at Eddington limit have speeds {approx}> 1000 km s{sup -1}. We also find that the ratio [2v {sup 2} {sub *} - (1 - {Gamma})v {sub .} {sup 2}]/v {sup 2} {sub c} dictates the amount of gas lost through winds. Used in conjunction with an appropriate relation between M {sub .} and M{sub h} and an appropriate opacity of dust grains in infrared (K band), this ratio has the attractive property of being minimum at a certain halo mass scale (M{sub h} {approx} 10{sup 12}-10{sup 12.5} M {sub Sun }) that signifies the crossover of AGN domination in outflow properties from starburst activity at lower masses. We find that stellar mass for massive galaxies scales as M {sub *}{proportional_to}M {sup 0.26} {sub h}, and for low-mass galaxies, M {sub *}{proportional_to}M {sup 5/3} {sub h}.

Sharma, Mahavir; Nath, Biman B., E-mail: mahavir@rri.res.in, E-mail: biman@rri.res.in [Raman Research Institute, Sadashiva Nagar, Bangalore 560080 (India)

2013-01-20T23:59:59.000Z

203

Fracture and Healing of Rock Salt Related to Salt Caverns  

SciTech Connect (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

204

Naturally fractured tight gas reservoir detection optimization. Final report  

SciTech Connect (OSTI)

This DOE-funded research into seismic detection of natural fractures is one of six projects within the DOE`s Detection and Analysis of Naturally Fractured Gas Reservoirs Program, a multidisciplinary research initiative to develop technology for prediction, detection, and mapping of naturally fractured gas reservoirs. The demonstration of successful seismic techniques to locate subsurface zones of high fracture density and to guide drilling orientation for enhanced fracture permeability will enable better returns on investments in the development of the vast gas reserves held in tight formations beneath the Rocky Mountains. The seismic techniques used in this project were designed to capture the azimuthal anisotropy within the seismic response. This seismic anisotropy is the result of the symmetry in the rock fabric created by aligned fractures and/or unequal horizontal stresses. These results may be compared and related to other lines of evidence to provide cross-validation. The authors undertook investigations along the following lines: Characterization of the seismic anisotropy in three-dimensional, P-wave seismic data; Characterization of the seismic anisotropy in a nine-component (P- and S-sources, three-component receivers) vertical seismic profile; Characterization of the seismic anisotropy in three-dimensional, P-to-S converted wave seismic data (P-wave source, three-component receivers); and Description of geological and reservoir-engineering data that corroborate the anisotropy: natural fractures observed at the target level and at the surface, estimation of the maximum horizontal stress in situ, and examination of the flow characteristics of the reservoir.

NONE

1997-11-19T23:59:59.000Z

205

ARE MOLECULAR OUTFLOWS AROUND HIGH-MASS STARS DRIVEN BY IONIZATION FEEDBACK?  

SciTech Connect (OSTI)

The formation of massive stars exceeding 10 M {sub Sun} usually results in large-scale molecular outflows. Numerical simulations, including ionization, of the formation of such stars show evidence for ionization-driven molecular outflows. Here we examine whether the outflows seen in these models reproduce the observations. We compute synthetic ALMA and CARMA maps of CO emission lines of the outflows, and compare their signatures to existing single-dish and interferometric data. We find that the ionization-driven models can only reproduce weak outflows around high-mass star-forming regions. We argue that expanding H II regions probably do not represent the dominant mechanism for driving observed outflows. We suggest instead that observed outflows are driven by the collective action of the outflows from the many lower-mass stars that inevitably form around young massive stars in a cluster.

Peters, Thomas; Klessen, Ralf S. [Institut fuer Theoretische Astrophysik, Universitaet Heidelberg, Zentrum fuer Astronomie, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany); Klaassen, Pamela D. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany); Mac Low, Mordecai-Mark [Department of Astrophysics, American Museum of Natural History, 79th Street at Central Park West, New York, NY 10024-5192 (United States); Banerjee, Robi, E-mail: tpeters@physik.uzh.ch [Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg (Germany)

2012-11-20T23:59:59.000Z

206

Ultrasound-Confirmed Frontal Bone Fracture  

E-Print Network [OSTI]

table--frontal sinus fractures. Facial Plast Surg Clin NorthConfirmed Frontal Bone Fracture Jeremy N. Johnson, DO Danielan isolated comminuted fracture of the left frontal sinus

Johnson, Jeremy N; Crandall, Stephen; Kang, Christopher S

2009-01-01T23:59:59.000Z

207

Fracture, aging and disease in bone  

E-Print Network [OSTI]

separate during bone fracture. Nature Materials 4, 612 (on nonagenarians with hip fractures? Injury 30, 169 (1999).bone mass as predictors of fracture in a prospective study.

Ager, J.W.; Balooch, G.; Ritchie, R.O.

2006-01-01T23:59:59.000Z

208

Self-potential observations during hydraulic fracturing  

E-Print Network [OSTI]

potential measurements during hydraulic fracturing of BunterSP response during hydraulic fracturing. Citation: Moore, J.observations during hydraulic fracturing, J. Geophys. Res. ,

Moore, J R; Glaser, Steven D

2007-01-01T23:59:59.000Z

209

Nucleosynthesis in the Outflow from Gamma Ray Burst Accretion Disks  

E-Print Network [OSTI]

We examine the nucleosynthesis products that are produced in the outflow from rapidly accreting disks. We find that the type of element synthesis varies dramatically with the degree of neutrino trapping in the disk and therefore the accretion rate of the disk. Disks with relatively high accretion rates such as 10 M_solar/s can produce very neutron rich nuclei that are found in the r process. Disks with more moderate accretion rates can produce copious amounts of Nickel as well as the light elements such as Lithium and Boron. Disks with lower accretion rates such as 0.1 M_solar/s produce large amounts of Nickel as well as some unusual nuclei such as Ti-49, Sc-45, Zn-64, and Mo-92. This wide array of potential nucleosynthesis products is due to the varying influence of electron neutrinos and antineutrinos emitted from the disk on the neutron-to-proton ratio in the outflow. We use a parameterization for the outflow and discuss our results in terms of entropy and outflow acceleration.

R. Surman; G. C. McLaughlin; W. R. Hix

2005-09-13T23:59:59.000Z

210

PROTOSTELLAR OUTFLOW HEATING IN A GROWING MASSIVE PROTOCLUSTER  

SciTech Connect (OSTI)

The dense molecular clump P1 in the infrared dark cloud complex G28.34+0.06 harbors a massive protostellar cluster at its extreme youth. Our previous Submillimeter Array observations revealed several jet-like CO outflows emanating from the protostars, indicative of intense accretion and potential interaction with ambient natal materials. Here, we present the Expanded Very Large Array spectral line observations toward P1 in the NH{sub 3} (J,K) = (1,1), (2,2), (3,3) lines, as well as H{sub 2}O and class I CH{sub 3}OH masers. Multiple NH{sub 3} transitions reveal the heated gas widely spread in the 1 pc clump. The temperature distribution is highly structured; the heated gas is offset from the protostars, and morphologically matches the outflows very well. Hot spots of spatially compact, spectrally broad NH{sub 3} (3,3) emission features are also found coincident with the outflows. A weak NH{sub 3} (3,3) maser is discovered at the interface between an outflow jet and the ambient gas. These findings suggest that protostellar heating may not be effective in suppressing fragmentation during the formation of massive cores.

Wang Ke; Wu Yuefang; Zhang Huawei [Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China); Zhang Qizhou [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Li Huabai, E-mail: kwang@cfa.harvard.edu [Max-Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany)

2012-02-15T23:59:59.000Z

211

Pressure grouting of fractured basalt flows  

SciTech Connect (OSTI)

This report describes a field trial of pressure grouting in basalt and the results of subsequent coring and permeability measurement activities. The objective was to show that the hydraulic conductivity of fractured basalt bedrock can be significantly reduced by pressure injection of cementitious materials. The effectiveness of the pressure grout procedure was evaluated by measuring the change in the hydraulic conductivity of the bedrock. The extent of grout penetration was established by analyzing postgrout injection drilling chips for the presence of a tracer in the grout and also by examining cores of the treated basalt. Downhole radar mapping was used to establish major lava flow patterns and follow water movement during a surface infiltration test. A site called Box Canyon, which is located northwest of the INEL, was chosen for this study due to the similarity of this surface outcrop geology to that of the underlying bedrock fracture system found at the Radioactive Waste Management Complex. This study showed that hydraulic conductivity of basalt can be reduced through pressure grouting of cementitious material.

Shaw, P.; Weidner, J.; Phillips, S.; Alexander, J.

1996-04-01T23:59:59.000Z

212

Development of an Improved Permeability Modification Simulator  

SciTech Connect (OSTI)

This report describes the development of an improved permeability modification simulator performed jointly by BDM Petroleum Technologies and Schlumberger Dowell under a cooperative research and development agreement (CRADA) with the US Department of Energy. The improved simulator was developed by modifying NIPER's PC-GEL permeability modification simulator to include a radial model, a thermal energy equation, a wellbore simulator, and a fully implicit time-stepping option. The temperature-dependent gelation kinetics of a delayed gel system (DGS) is also included in the simulator.

Gao, H.W.; Elphnick, J.

1999-03-09T23:59:59.000Z

213

Advanced hydraulic fracturing methods to create in situ reactive barriers  

SciTech Connect (OSTI)

Many contaminated areas consist of a source area and a plume. In the source area, the contaminant moves vertically downward from a release point through the vadose zone to an underlying saturated region. Where contaminants are organic liquids, NAPL may accumulate on the water table, or it may continue to migrate downward through the saturated region. Early developments of permeable barrier technology have focused on intercepting horizontally moving plumes with vertical structures, such as trenches, filled with reactive material capable of immobilizing or degrading dissolved contaminants. This focus resulted in part from a need to economically treat the potentially large volumes of contaminated water in a plume, and in part from the availability of construction technology to create the vertical structures that could house reactive compounds. Contaminant source areas, however, have thus far remained largely excluded from the application of permeable barrier technology. One reason for this is the lack of conventional construction methods for creating suitable horizontal structures that would place reactive materials in the path of downward-moving contaminants. Methods of hydraulic fracturing have been widely used to create flat-lying to gently dipping layers of granular material in unconsolidated sediments. Most applications thus far have involved filling fractures with coarse-grained sand to create permeable layers that will increase the discharge of wells recovering contaminated water or vapor. However, it is possible to fill fractures with other compounds that alter the chemical composition of the subsurface. One early application involved development and field testing micro-encapsulated sodium percarbonate, a solid compound that releases oxygen and can create aerobic conditions suitable for biodegradation in the subsurface for several months.

Murdoch, L. [FRx Inc., Cincinnati, OH (United States); [Clemson Univ., SC (United States); Siegrist, B. [Oak Ridge National Lab., TN (United States); Vesper, S. [Univ. of Cincinnati, OH (United States)] [and others

1997-12-31T23:59:59.000Z

214

Satellite observations of Mexico City pollution outflow from the Tropospheric Emissions Spectrometer (TES)  

E-Print Network [OSTI]

Satellite observations of Mexico City pollution outflow from the Tropospheric Emissions 12 November 2008 Keyword: Mega-city pollution TES O3­CO correlation INTEX-B Mexico city a b s t r a c regions were used to examine Mexico City pollution outflow on a regional scale. The pollution outflow from

215

Coordinated studies in support of hydraulic fracturing of coalbed methane. Annual report, November 1991-December 1992  

SciTech Connect (OSTI)

The purpose of the work is to characterize common and potential fracturing fluids in terms of coal-fluid interactions to identify reasons for less than satisfactory performance and to ultimately devise alternative fluids and treatment procedures to optimize production following hydraulic fracturing. The laboratory data reported herein has proven helpful in designing improved hydraulic fracturing treatments and remedial treatments in the Black Warrior Basin. Acid inhibitors, scale inhibitors, additives to improve coal relative permeability to gas, and non-damaging polymer systems for hydraulic fracturing have been screened in coal damage tests. The optimum conditions for creating field-like foams in the laboratory have been explored. Tests have been run to identify minimum polymer and surfactant concentrations for applications of foam in coal. The roll of 100 mesh sand in controlling leakoff and impairing conductivity in coal has been investigated.

Not Available

1993-04-01T23:59:59.000Z

216

Investigation of Created Fracture Geometry through Hydraulic Fracture Treatment Analysis  

E-Print Network [OSTI]

Successful development of shale gas reservoirs is highly dependent on hydraulic fracture treatments. Many questions remain in regards to the geometry of the created fractures. Production data analysis from some shale gas wells quantifies a much...

Ahmed, Ibraheem 1987-

2012-11-30T23:59:59.000Z

217

Hydrogen-Assisted Fracture: Materials Testing and Variables Governing Fracture  

E-Print Network [OSTI]

Hydrogen-Assisted Fracture: Materials Testing and Variables Governing Fracture Brian Somerday for producing both strength of materials and fracture mechanics data H H HH H H d/dt > 0 strength of materials: UTS, YS, f, RA H2 H2H2 H2 H2 H2 H2 H2 HH H H H H H H H H d/dt 0 fracture mechanics: KIH, KTH

218

Reservoir fracture characterizations from seismic scattered waves  

E-Print Network [OSTI]

The measurements of fracture parameters, such as fracture orientation, fracture density and fracture compliance, in a reservoir is very important for field development and exploration. Traditional seismic methods for ...

Fang, Xinding

2012-01-01T23:59:59.000Z

219

Hydrogen Permeability and Integrity of Hydrogen  

E-Print Network [OSTI]

Hydrogen Permeability and Integrity of Hydrogen Delivery Pipelines Z. Feng*, L.M. Anovitz*, J and industry expectations · DOE Pipeline Working Group and Tech Team activities - FRP Hydrogen Pipelines - Materials Solutions for Hydrogen Delivery in Pipelines - Natural Gas Pipelines for Hydrogen Use #12;3 OAK

220

WINTER PERFORMANCE ASSESSMENT OF PERMEABLE PAVEMENTS  

E-Print Network [OSTI]

WINTER PERFORMANCE ASSESSMENT OF PERMEABLE PAVEMENTS A COMPARATIVE STUDY OF POROUS ASPHALT, PERVIOUS CONCRETE, AND CONVENTIONAL ASPHALT IN A NORTHERN CLIMATE BY KRISTOPHER M. HOULE BS, Worcester the University of New Hampshire, the Northern New England Concrete Promotion Association (NNECPA), the Northeast

Note: This page contains sample records for the topic "outflow fracture permeability" 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

Permeable Pavements, Green Roofs, and Cisterns  

E-Print Network [OSTI]

, and water harvesting through them, such as asphalt and con- systems or cisterns. This new fact sheet crete and improve the water quality of runoff from new residential and commercial developments by using stormwater including the use of permeable pave- (sufaces that do not allow water to filter ments, green roofs

Hunt, William F.

222

Effective Permeability Change in Wellbore Cement with Carbon Dioxide Reaction  

SciTech Connect (OSTI)

Portland cement, a common sealing material for wellbores for geological carbon sequestration was reacted with CO{sub 2} in supercritical, gaseous, and aqueous phases at various pressure and temperature conditions to simulate cement-CO{sub 2} reaction along the wellbore from carbon injection depth to the near-surface. Hydrated Portland cement columns (14 mm diameter x 90 mm length; water-to-cement ratio = 0.33) including additives such as steel coupons and Wallula basalt fragments were reacted with CO{sub 2} in the wet supercritical (the top half) and dissolved (the bottom half) phases under carbon sequestration condition with high pressure (10 MPa) and temperature (50 C) for 5 months, while small-sized hydrated Portland cement columns (7 mm diameter x 20 mm length; water-to-cement ratio = 0.38) were reacted with CO{sub 2} in dissolved phase at high pressure (10 MPa) and temperature (50 C) for 1 month or with wet CO{sub 2} in gaseous phase at low pressure (0.2 MPa) and temperature (20 C) for 3 months. XMT images reveal that the cement reacted with CO{sub 2} saturated groundwater had degradation depth of {approx}1 mm for 1 month and {approx}3.5 mm for 5 month, whereas the degradation was minor with cement exposure to supercritical CO{sub 2}. SEM-EDS analysis showed that the carbonated cement was comprised of three distinct zones; the innermost less degraded zone with Ca atom % > C atom %, the inner degraded zone with Ca atom % {approx} C atom % due to precipitation of calcite, the outer degraded zone with C atom % > Ca atom % due to dissolution of calcite and C-S-H, as well as adsorption of carbon to cement matrix. The outer degraded zone of carbonated cement was porous and fractured because of dissolution-dominated reaction by carbonic acid exposure, which resulted in the increase in BJH pore volume and BET surface area. In contrast, cement-wet CO{sub 2}(g) reaction at low P (0.2 MPa)-T (20 C) conditions for 1 to 3 months was dominated by precipitation of micron-sized calcite on the outside surface of cement, which resulted in the decrease in BJH pore volume and BET surface area. Cement carbonation and pore structure change are significantly dependent on pressure and temperature conditions as well as the phase of CO{sub 2}, which controls the balance between precipitation and dissolution in cement matrix. Geochemical modeling result suggests that ratio of solid (cement)-to-solution (carbonated water) has a significant effect on cement carbonation, thus the cement-CO{sub 2} reaction experiment needs to be conducted under realistic conditions representing the in-situ wellbore environment of carbon sequestration field site. Total porosity and air permeability for a duplicate cement column with water-to-cement ratio of 0.38 measured after oven-drying by Core Laboratories using Boyle's Law technique and steady-state method were 31% and 0.576 mD. A novel method to measure the effective liquid permeability of a cement column using X-ray micro-tomography images after injection of pressurized KI (potassium iodide) is under development by PNNL. Preliminary results indicate the permeability of a cement column with water-to-cement ratio of 0.38 is 4-8 mD. PNNL will apply the method to understand the effective permeability change of Portland cement by CO{sub 2}(g) reaction under a variety of pressure and temperature conditions to develop a more reliable well-bore leakage risk model.

Um, Wooyong; Jung, Hun Bok; Martin, Paul F.; McGrail, B. Peter

2011-11-01T23:59:59.000Z

223

Seismic Fracture Characterization Methods for Enhanced Geothermal...  

Broader source: Energy.gov (indexed) [DOE]

Seismic Fracture Characterization Methods for Enhanced Geothermal Systems Seismic Fracture Characterization Methods for Enhanced Geothermal Systems Project objective: Make Seismic...

224

Seismic Fracture Characterization Methods for Enhanced Geothermal...  

Broader source: Energy.gov (indexed) [DOE]

Seismic Fracture Characterization Methods for Enhanced Geothermal Systems; 2010 Geothermal Technology Program Peer Review Report Seismic Fracture Characterization Methods for...

225

Fluid Flow Modeling in Fractures  

E-Print Network [OSTI]

In this paper we study fluid flow in fractures using numerical simulation and address the challenging issue of hydraulic property characterization in fractures. The methodology is based on Computational Fluid Dynamics, ...

Sarkar, Sudipta

2004-01-01T23:59:59.000Z

226

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

SciTech Connect (OSTI)

A simple conceptual model has been recently developed for analyzing pressure and temperature data from flowing fluid temperature logging (FFTL) in unsaturated fractured rock. Using this conceptual model, we developed an analytical solution for FFTL pressure response, and a semianalytical solution for FFTL temperature response. We also proposed a method for estimating fracture permeability from FFTL temperature data. The conceptual model was based on some simplifying assumptions, particularly that a single-phase airflow model was used. In this paper, we develop a more comprehensive numerical model of multiphase flow and heat transfer associated with FFTL. Using this numerical model, we perform a number of forward simulations to determine the parameters that have the strongest influence on the pressure and temperature response from FFTL. We then use the iTOUGH2 optimization code to estimate these most sensitive parameters through inverse modeling and to quantify the uncertainties associated with these estimated parameters. We conclude that FFTL can be utilized to determine permeability, porosity, and thermal conductivity of the fracture rock. Two other parameters, which are not properties of the fractured rock, have strong influence on FFTL response. These are pressure and temperature in the borehole that were at equilibrium with the fractured rock formation at the beginning of FFTL. We illustrate how these parameters can also be estimated from FFTL data.

Mukhopadhyay, S.; Tsang, Y.; Finsterle, S.

2009-01-15T23:59:59.000Z

227

Permeability anisotropy and resistivity anisotropy of mechanically compressed mudrocks  

E-Print Network [OSTI]

Permeability anisotropy (the ratio of the horizontal to vertical permeability) is an important parameter used in sedimentary basin models and geotechnical design to model fluid flow, locate hydrocarbon reserves and estimate ...

Adams, Amy Lynn

2014-01-01T23:59:59.000Z

228

Moisture Durability of Vapor Permeable Insulating Sheathing (Fact Sheet)  

SciTech Connect (OSTI)

In this project, Building America team Building Science Corporation researched some of the ramifications of using exterior, vapor permeable insulation on retrofit walls with vapor permeable cavity insulation. Retrofit strategies are a key factor in reducing exterior building stock consumption.

Not Available

2013-10-01T23:59:59.000Z

229

The measurement of gas relative permeability for low permeability cores using a pressure transient method  

E-Print Network [OSTI]

of oil and gas from a. typical reservoir. However, determining relative permeability ac- curately, especially for tight formations, has been a, challenging problem to petroleum engineers for many years. Commonly used laboratory methods of measuring.... Generally, there exist three kinds of fluids in petroleum reservoirs, oil, gas and water. In petroleum engineering, relative permeability of formation is one of the most important parameters one must use to estimate the fluid flow rates and recoveries...

Ning, Xiuxu

2012-06-07T23:59:59.000Z

230

Self-potential observations during hydraulic fracturing  

E-Print Network [OSTI]

1968), Permeability of granite under high pressure, J.permeability of Westerly granite, J. Geophys. Res. , 80(5),resistivity during creep in granite, Pure Appl. Geophys. ,

Moore, J R; Glaser, Steven D

2007-01-01T23:59:59.000Z

231

Chemical Signatures of and Precursors to Fractures Using Fluid Inclusion Stratigraphy  

SciTech Connect (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

232

FRACTURE STIMULATION IN ENHANCED GEOTHERMAL  

E-Print Network [OSTI]

FRACTURE STIMULATION IN ENHANCED GEOTHERMAL SYSTEMS A REPORT SUBMITTED TO THE DEPARTMENT OF ENERGY of stimulation is induced shear on preexisting fractures, which increases their transmissibility by orders of magnitude. The processes that create fractured rock are discussed from the perspective of geology and rock

Stanford University

233

Characterization and simulation of an exhumed fractured petroleum reservoir. Final report, March 18, 1996--September 30, 1998  

SciTech Connect (OSTI)

An exhumed fractured reservoir located near Alligator Ridge in central Nevada provides the basis for developing and testing different approaches for simulating fractured petroleum reservoirs. The fractured analog reservoir comprises a 90 m thickness of silty limestone and shaly interbeds within the Devonian Pilot Shale. A period of regional compression followed by ongoing basin and range extension has created faults and fractures that, in tern, have controlled the migration of both oil and gold ore-forming fluids. Open pit gold mines provide access for observing oil seepage, collecting the detailed fracture data needed to map variations in fracture intensity near faults, build discrete fracture network models and create equivalent permeability structures. Fault trace patterns mapped at the ground surface provide a foundation for creating synthetic fault trace maps using a stochastic procedure conditioned by the outcrop data. Conventional simulations of petroleum production from a 900 by 900 m sub-domain within the reservoir analog illustrate the possible influence of faults and fractures on production. The consequences of incorporating the impact of different stress states (e.g., extension, compression or lithostatic) are also explored. Simulating multiphase fluid flow using a discrete fracture, finite element simulator illustrates how faults acting as conduits might be poorly represented by the upscaling procedures used to assign equivalent permeability values within reservoir models. The parallelized reservoir simulators developed during this project provide a vehicle to evaluate when it might be necessary to incorporate very fine scale grid networks in conventional reservoir simulators or to use finely gridded discrete fracture reservoir simulators.

Forster, C.B.; Nielson, D.L.; Deo, M.

1998-12-01T23:59:59.000Z

234

Permeability Evaluation in Heterogcmecw Formations Eiocldy of Petroleum Engineers  

E-Print Network [OSTI]

~ SPE 26060 Permeability Evaluation in Heterogcmecw Formations Eiocldy of Petroleum Engineers Lking for reservoir characterization. The permeability of the formation is usually evaluated from the cores and of permeability from well log data represents a significant technical as weli as economic advantage

Mohaghegh, Shahab

235

EXPERIMENTAL DETERMINATION OF STEAM WATER RELATIVE PERMEABILITY RELATIONS  

E-Print Network [OSTI]

EXPERIMENTAL DETERMINATION OF STEAM WATER RELATIVE PERMEABILITY RELATIONS A REPORT SUBMITTED;Abstract A set of relative permeability relations for simultaneous ow of steam and water in porous media with saturation and pressure measurements. These relations show that the relative permeability for steam phase

Stanford University

236

Results of a 1995 hydraulic fracturing survey and a comparison of 1995 and 1990 industry practices  

SciTech Connect (OSTI)

This paper presents the results of a hydraulic fracturing survey conducted in 1995 on behalf of the Gas Research institute (GRI). The purpose of the survey was to determine the types of formations that are normally fracture treated; gather data on the fracture treatments that are normally pumped; determine the level of data collection being conducted in the field; determine the level of data analysis being conducted in the office and the field; solicit opinions on the level of technology required to obtain an accurate analysis for fracture treatments; solicit opinions of the limitations of current technology; determine what costs operators could justify to analyze fracture treatment data and obtain ideas on new areas of research. Data gathered in the survey included respondents company size (major, large/small independent, service company or consultant), geographical area of operation, well depths and permeabilities, fracture treatment size, proppant type and volume, level of detail in data gathering, fracture treatment design and real-time analysis. The 1995 data were compared to a similar survey conducted in 1990 by GRI to determine technology trends.

Carter, R.H.; Holditch, S.A.; Wolhart, S.L.

1996-12-31T23:59:59.000Z

237

Coordinated studies in support of hydraulic fracturing of coalbed methane. Annual report, June 1990-October 1991  

SciTech Connect (OSTI)

The production of natural gas coal typically requires stimulation in the form of hydraulic fracturing. The results of hydraulic fracturing treatments have ranged from highly successful to less than satisfactory. The approach in the work has been to experimentally evaluate parameters that pertain to coal fluid interactions during hydraulic fracturing and post-frac production and then apply the findings to the selection of fracturing fluids and treatment design. Evaluated parameters include leakoff through cleats, pressure drops through cleated slots with slurries, proppant transport, conductivity, and coal matrix damage due to fracturing fluids. Some conclusions from the work include (1) 100 mesh sand alone can control leakoff through cleats; (2) coal faces alone do not increase pressure drop through fractures with slurries; (3) restrictions approaching 2 proppant diameters are required to see pressure increases; (4) borate fluid pH's of 9.5 are required for transport; (5) mixed proppant conductivities of 100 mesh and 16/30 can be 50% lower than the larger proppant; (6) guar based fracturing fluids can cause up to 90% permeability damage to the coal matrix; (7) HEC containing foams provide the best cleanup in the laboratory (only 10 to 30% damage and have shown excellent results in field trials); and (8) expanded use of COMPAS is recommended to document field results.

Penny, G.S.; Conway, M.W.

1992-04-01T23:59:59.000Z

238

Stress and Permeability Heterogeneity within the Dixie Valley Geothermal Reservoir: Recent Results from Well 82-5  

SciTech Connect (OSTI)

We collected borehole televiewer, temperature and flowmeter logs and conducted a hydraulic fracturing test in a well (82-5) that penetrated the SFZ within the known boundaries of the geothermal field but which failed to encounter significant permeability. Although stuck drill pipe prevented direct access to the SFZ, borehole breakouts and cooling cracks indicated a {approximately}90 degree rotation in the azimuth of the least horizontal principal stress (Shmin) in well 82-5 at about 2.7 km depth. This rotation, together with the low (Shmin) magnitude measured at 2.5 km depth in well 82-5, is most readily explained through the occurrences of one or more normal faulting earthquakes in the hanging wall of the SFZ in the northern part of the reservoir. The orientation of (Shmin) below 2.7 km (i.e., {approximately}20 to 50 m above the top of the SFZ) is such that both the overall SFZ and natural fractures directly above the SFZ are optimally oriented for normal faulting failure. If these fracture and stress orient ations persist into the SFZ itself, then the existence of a local stress relief zone (i.e., anormalously high (Shmin) magnitude) is the most likely explanation for the very low fault zone permeability encountered in well 82-5.

S. H. Hickman; M. D. Zoback; C. A. Barton; R. Benoit; J. Svitek; R. Summers

1999-12-01T23:59:59.000Z

239

Water injection into a Low-Permeability Rock - 2: Control Model  

SciTech Connect (OSTI)

In Part 1, we have demonstrated the inevitable growth of the fluid injection hydrofractures in low-permeability rocks. Thus, a smart controller that manages fluid injection in the presence of hydrofracture extension is highly desirable. Such a controller will be an essential part of automated waterflood project surveillance and control. Here we design an optimal injection controller using methods of optimal control theory. The controller inputs are the history of the injection pressure and the cumulative injection, along with the fracture size. The output parameter is the injection pressure and the control objective is the injection rate. We demonstrate that the optimal injection pressure depends not only on the instantaneous measurements, but it is determined by the whole history of the injection and of the fracture area growth. We show the controller robustness when the inputs are delayed and noisy and when the fracture undergoes abrupt extensions. Finally, we propose a procedure that allows estimation of the hydrofracture size at no additional cost.

Silin, Dmitriy B.; Patzek, Tad W.

1999-06-01T23:59:59.000Z

240

Modifications of Carbonate Fracture Hydrodynamic Properties by CO{sub 2}-Acidified Brine Flow  

SciTech Connect (OSTI)

Acidic reactive flow in fractures is relevant in subsurface activities such as CO{sub 2} geological storage and hydraulic fracturing. Understanding reaction-induced changes in fracture hydrodynamic properties is essential for predicting subsurface flows such as leakage, injectability, and fluid production. In this study, x-ray computed tomography scans of a fractured carbonate caprock were used to create three dimensional reconstructions of the fracture before and after reaction with CO{sub 2}-acidified brine (Ellis et al., 2011, Greenhouse Gases: Sci. Technol., 1:248-260). As expected, mechanical apertures were found to increase substantially, doubling and even tripling in some places. However, the surface geometry evolved in complex ways including ‘comb-tooth’ structures created from preferential dissolution of calcite in transverse sedimentary bands, and the creation of degraded zones, i.e. porous calcite-depleted areas on reacted fracture surfaces. These geometric alterations resulted in increased fracture roughness, as measured by surface Z{sub 2} parameters and fractal dimensions D{sub f}. Computational fluid dynamics (CFD) simulations were conducted to quantify the changes in hydraulic aperture, fracture transmissivity and permeability. The results show that the effective hydraulic apertures are smaller than the mechanical apertures, and the changes in hydraulic apertures are nonlinear. Overestimation of flow rate by a factor of two or more would be introduced if fracture hydrodynamic properties were based on mechanical apertures, or if hydraulic aperture is assumed to change proportionally with mechanical aperture. The differences can be attributed, in part, to the increase in roughness after reaction, and is likely affected by contiguous transverse sedimentary features. Hydraulic apertures estimated by the 1D statistical model and 2D local cubic law (LCL) model are consistently larger than those calculated from the CFD simulations. In addition, a novel ternary segmentation method was devised to handle the degraded zones, allowing for a bounding analysis of the effects on hydraulic properties. We found that the degraded zones account for less than 15% of the fracture volume, but cover 70% to 80% of the fracture surface. When the degraded zones are treated as part of the fracture, the fracture transmissivities are two to four times larger because the fracture surfaces after reaction are not as rough as they would be if one considers the degraded zone as part of the rock. Therefore, while degraded zones created during geochemical reactions may not significantly increase mechanical aperture, this type of feature cannot be ignored and should be treated with prudence when predicting fracture hydrodynamic properties.

Deng, Hang; Ellis, Brian R.; Peters, Catherine A.; Fitts, Jeffrey P.; Crandall, Dustin; Bromhal, Grant S.

2013-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "outflow fracture permeability" 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

The impact of gravity segregation on multiphase non-Darcy flow in hydraulically fractured gas wells  

E-Print Network [OSTI]

Solution for Uniform Influx................................. 28 2.5 Effect of Stress on Non-Darcy Flow with Uniform Influx............................. 40 2.6 Hydraulically Fractured Reservoir with Two-Phase Flow ............................. 45 2... ............................................................................................................... 21 2.6 Gas expansion factor divided by gas viscosity Eg/µg = 1/(Bµ), which is roughly constant at or above pressures of 6,000 psi. .................................... 22 2.7 Relative permeability functions from Table 2.1 normalized...

Dickins, Mark Ian

2008-10-10T23:59:59.000Z

242

PERMEABILITY TESTING OF SIMULATED SALTSTONE CORE AND VAULT 4 CELL E SALTSTONE  

SciTech Connect (OSTI)

The Engineering Process Development Group (EPD) of the Savannah River National Laboratory (SRNL) prepared simulated saltstone core samples to evaluate the effect of sample collection by coring on the permeability of saltstone. The Environmental Restoration Technology Section (ERTS) of the SRNL was given the task of measuring the permeability of cores of simulated saltstone. Saltstone samples collected from Vault 4 Cell E using both dry and wet coring methods were also submitted for permeability analysis. The cores from Vault 4 Cell E were in multiple pieces when they were recovered (Smith, 2008 Cheng et.al, 2009). Permeability testing was only performed on the portions of the core sample that were intact, had no visible fractures or cracks, and met the specifications for 'undisturbed specimens' identified in Method ASTM D5084-03 Standard Test Methods for Measurement of Hydraulic Conductivity of Saturated Porous Materials Using a Flexible Wall Permeameter that was used for the testing. Permeability values for cores of simulated saltstone compared with values from permeability tests conducted on molded saltstone samples by an independent laboratory using the same method. All hydraulic conductivity results for Vault 4 samples exceeded results for both molded and cored saltstone simulant samples. The average hydraulic conductivity result for Vault 4 Cell E samples of 3.9 x 10{sup -7} cm/sec is approximately two orders of magnitude greater than that of the simulated saltstone with an average of 4.1 x 10{sup -9} cm/sec. Numerical flow and transport simulations of moisture movement through saltstone performed for the performance assessment of the Saltstone Disposal Facility (SDF) used 2.0 x 10{sup -9} cm/sec for the hydraulic conductivity of saltstone (Flach et al, 2009). The results for simulated versus actual saltstone were further compared using non-parametric statistics. The results from non-parametric statistical analysis of results indicate that there is at least a 98% probability that the hydraulic conductivity of saltstone samples collected from Vault 4 Cell E saltstone is greater than that of the baseline simulant mix.

Nichols, R.; Dixon, K.

2011-08-22T23:59:59.000Z

243

Laboratory imaging of stimulation fluid displacement from hydraulic fractures  

SciTech Connect (OSTI)

Laboratory experiments were conducted to physically investigate the processes governing stimulation fluid displacement from hydraulic fractures. Experiments were performed on two scales: meter-scale in a 1500 cm{sup 2} sand pack and core-scale in a 65 cm{sup 2} API linear conductivity cell. High-resolution light transmission imaging was employed at the meter-scale to visualize and quantify processes governing fluid displacement. For comparison, complimentary tests were performed using an API conductivity cell under ambient test conditions and at elevated closure stress. In these experiments viscous fingering and gravity drainage were identified as the dominant processes governing fluid displacement. Fluid viscosity was found to dictate the relative importance of the competing displacement processes and ultimately determine the residual liquid saturation of the sand pack. The process by which fluid displacement occurs was seen to effect the shape of both the gas and liquid phase relative permeability functions. Knowledge of such viscosity/relative permeability relationships may prove useful in bounding predictions of post-stimulation recovery of gels from the fracture pack.

Tidwell, V. [Sandia National Lab., Albuquerque, NM (United States); Parker, M. [SPE, Richardson, TX (United States)

1996-11-01T23:59:59.000Z

244

Endothelial cell permeability to water and antipyrine  

SciTech Connect (OSTI)

The endothelium provides a structural barrier between plasma constituents and the tissues. The permeability characteristics of the the endothelial cells regulate the transcellular movement of materials across this barrier while other movement is paracellular. In this study the permeability of the endothelial cells to tritiated water (/sup 3/HHO) and /sup 14/C-labeled antipyrine (AP) was investigated. The cells were isolated non-enzymatically from calf pulmonary artery and were maintained in culture and used between the seventh and fifteenth passage. The cells were removed from the T-flasks with a rubber policeman, titurated with a 22g needle and centrifuged. The cells were mixed with an extracellular marker, drawn into polyethylene tubing and packed by centrifugation for use in the linear diffusion technique. All measurements were made at 37 C. The diffusion coefficients for /sup 3/HHO through the packed cells (D), the intracellular material (D/sub 2/), and the extracellular material (D/sub 1/) were 0.682, 0.932 and 2.45 x 10/sup -5/ cm/sup 2/ s/sup -1/ and for AP were 0.273, 0.355 and 1.13 x 10/sup -5/ cm/sup 2/ s/sup -1/ respectively. The permeability coefficient calculated by the series-parallel pathway model for /sup 3/HHO was higher than that for AP and for both /sup 3/HHO and AP were lower than those calculated for isolated lung cells and erythrocytes.

Garrick, R.A.

1986-03-05T23:59:59.000Z

245

Fracture Characterization in Enhanced Geothermal Systems by Wellbore...  

Broader source: Energy.gov (indexed) [DOE]

Nanosensors for Fractured Reservoir Characterization. 2. Characterization of Fracture Properties using Production Data. 3. Fracture Characterization by Resistivity...

246

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

E-Print Network [OSTI]

in Single Rock Joints", Licentiate Thesis, Lulea Universityof Technology, Lulea, Sweden. Heiba, A. A. , Sahimi, M. ,

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

1989-01-01T23:59:59.000Z

247

EFFECTS OF SAMPLE SIZE ON THE STRESS-PERMEABILITY RELATIONSHIP FOR NATURAL FRACTURES  

E-Print Network [OSTI]

APPENDIX B: REFORMATORY GRANITE AND CORE DEFORMATION DATAProperties of in situ Jointed Granite," Int Mech. Min. Sci.Whole and Jointed Barrier Granite," Int. J. Rock Mech. Min.

Gale, J.E.

2013-01-01T23:59:59.000Z

248

A new coal-permeability model: Internal swelling stress and fracture-matrix interaction  

E-Print Network [OSTI]

gas sequestration into coal seams. J Geophys Res. (2007)Reservoir engineering in coal seams: Part 1 – the physicaland movement in coal seams. SPE Reservoir engineering.

Liu, H.H.

2010-01-01T23:59:59.000Z

249

A New Coal-Permeability Model: Internal Swelling Stress and Fracture–Matrix Interaction  

E-Print Network [OSTI]

gas sequestration into coal seams. J Geophys. Res. (2007).Reservoir engineering in coal seams: part 1—the physicalstorage and movement in coal seams. SPE Reserv. Eng. , 2(1),

Liu, Hui-Hai; Rutqvist, Jonny

2010-01-01T23:59:59.000Z

250

EFFECTS OF SAMPLE SIZE ON THE STRESS-PERMEABILITY RELATIONSHIP FOR NATURAL FRACTURES  

E-Print Network [OSTI]

geology problems. Rock slope design, mine drainage, and the effective exploration and development of oil,

Gale, J.E.

2013-01-01T23:59:59.000Z

251

A New Coal-Permeability Model: Internal Swelling Stress and Fracture–Matrix Interaction  

E-Print Network [OSTI]

In: Proceedings of the Coalbed Methane Symposium, Universitynumerical simulation for coalbed-methane-recovery process.coal with enhanced coalbed methane recovery—a review. Energy

Liu, Hui-Hai; Rutqvist, Jonny

2010-01-01T23:59:59.000Z

252

A new coal-permeability model: Internal swelling stress and fracture-matrix interaction  

E-Print Network [OSTI]

in coal with enhanced coalbed methane recovery ? a review.Proceedings of the coalbed methane symposium, University ofProceedings of the coalbed methane symposium, University of

Liu, H.H.

2010-01-01T23:59:59.000Z

253

Final Report Multiazimuth Seismic Diffraction Imaging for Fracture Characterization in Low-Permeability  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsing ZirconiaPolicyFeasibilityField Office ProgramsFinal7,Administrator's

254

A new coal-permeability model: Internal swelling stress and fracture-matrix interaction  

E-Print Network [OSTI]

of carbon dioxide in coal with enhanced coalbed methaneL. Adsorption-induced coal swelling and stress: Implicationsand acid gas sequestration into coal seams. J Geophys Res. (

Liu, H.H.

2010-01-01T23:59:59.000Z

255

Use of Tracers to Characterize Fractures in Engineered Geothermal...  

Broader source: Energy.gov (indexed) [DOE]

Fractures in Engineered Geothermal Systems Project Objectives: Measure interwell fracture surface area and fracture spacing using sorbing tracers; measure fracture surface...

256

Procedure for estimating fracture energy from fracture surface roughness  

DOE Patents [OSTI]

The fracture energy of a material is determined by first measuring the length of a profile of a section through a fractured surface of the material taken on a plane perpendicular to the mean plane of that surface, then determining the fractal dimensionality of the surface. From this, the yield strength of the material, and the Young's Modulus of that material, the fracture energy is calculated.

Williford, Ralph E. (Kennewick, WA)

1989-01-01T23:59:59.000Z

257

Method for fracturing silicon-carbide coatings on nuclear-fuel particles  

DOE Patents [OSTI]

This invention is a device for fracturing particles. It is designed especially for use in "hot cells" designed for the handling of radioactive materials. In a typical application, the device is used to fracture a hard silicon-carbide coating present on carbon-matrix microspheres containing nuclear-fuel material, such as uranium or thorium compounds. To promote remote control and facilitate maintenance, the particle breaker is pneumatically operated and contains no moving parts. It includes means for serially entraining the entrained particles on an anvil housed in a leak-tight chamber. The flow rate of the gas is at a value effecting fracture of the particles; preferably, it is at a value fracturing them into product particulates of fluidizable size. The chamber is provided with an outlet passage whose cross-sectional area decreases in the direction away from the chamber. The outlet is connected tangentially to a vertically oriented vortex-flow separator for recovering the product particulates entrained in the gas outflow from the chamber. The invention can be used on a batch or continuous basis to fracture the silicon-carbide coatings on virtually all of the particles fed thereto.

Turner, Lloyd J. (Oak Ridge, TN); Willey, Melvin G. (Knoxville, TN); Tiegs, Sue M. (Lenoir City, TN); Van Cleve, Jr., John E. (Kingston, TN)

1982-01-01T23:59:59.000Z

258

YSO Jets and Molecular Outflows: Tracing the History of Star Formation  

E-Print Network [OSTI]

Collimated outflows from Young Stellar Objects (YSOs) can be seen as tracers of the accretion powered systems which drive them. In this paper I review some theoretical and observational aspects of YSO outflows through the prism of questions relating to the protostellar source. The issue I address is: can collimated outflows be used as ``fossils'' allowing the history of protostellar evolution to be recovered? Answering this question relies on accurately identifying where theoretical tools and observational diagnostics converge to provide unique solutions of the protostellar physics. I discuss potential links between outflow and source including the time and direction variability of jets, the jet/molecular outflow connection, and the the effect of magnetic fields. I also discuss models of the jet/outflow collimation mechanism.

Adam Frank

1998-04-29T23:59:59.000Z

259

Determination of the effective stress law for permeability and deformation in low-permeability rocks  

SciTech Connect (OSTI)

This paper reports that laboratory experiments were performed to determine the effective stress law of tight sandstones and chalk for permeability and deformation. Permeability and volumetric strain data were taken at various stresses and pore pressures and were analyzed with a statistical model-building approach. Results show that the effective stress laws for both processes are variable with stress and pressure, depend on the material, and do not agree well with present theories. This may be applied for a greater understanding of oil reservoir formations.

Warpinski, N.R.; Teufel, L.W. (Sandia National Lab. (US))

1992-06-01T23:59:59.000Z

260

Brittle Fracture Ductile to Brittle transition  

E-Print Network [OSTI]

FRACTURE Brittle Fracture Ductile to Brittle transition Fracture Mechanics T.L. Anderson CRC sulphur in steel Residual stress Continuity of the structure Microcracks #12;Fracture Brittle Ductile Factors affecting fracture Strain rate State of stress Temperature #12;Behaviour described Terms Used

Subramaniam, Anandh

Note: This page contains sample records for the topic "outflow fracture permeability" 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

Spectral Evidence for Widespread Galaxy Outflows at z>4  

E-Print Network [OSTI]

We present discovery spectra of a sample of eight lensed galaxies at high redshift, 3.7outflow velocity of interstellar gas. Local starburst galaxies show similar behavior, associated with obvious gas outflows. We also find a trend of increasing equivalent width of Ly-alpha emission with redshift, which may be a genuine evolutionary effect towards younger stellar populations at high redshift with less developed stellar continua. No obvious emission is detected below the Lyman limit in any of our spectra, nor in deep U or B-band images. The UV continua are reproduced well by early B-stars, although some dust absorption would allow a fit to hotter stars. After correcting for the lensing, we derive small physical sizes for our objects, ~0.5-5 kpc/h for a flat cosmology with Omega_m=0.3, Omega_Lambda=0.7. The lensed images are only marginally resolved in good seeing despite their close proximity to the critical curve, where large arcs are visible and hence high magnifications of up to ~20x are inferred. Two objects show a clear spatial extension of the Ly-alpha emission relative to the continuum starlight, indicating a ``breakout'' of the gas. The sizes of our galaxies together with their large gas motion suggests that outflows of gas are common at high redshift and associated with galaxy formation.

Brenda Frye; Tom Broadhurst; Narciso Benitez

2001-12-04T23:59:59.000Z

262

Wood smoke inhalation increases pulmonary microvascular permeability  

SciTech Connect (OSTI)

The effect of wood smoke inhalation (SI) on pulmonary vascular permeability was studied in open-chested, anesthetized dogs. Animals were divided into two groups. A prenodal lymphatic vessel was cannulated in group I (n = 7), and baseline (BL) lung lymph flow (QL) and lymph (CL) and plasma (CP) protein concentrations were measured. The animals' lungs were then ventilated with wood smoke for 5 minutes. Left atrial pressure (Pla) was increased above baseline (mean 16.7 +/- 2.2 mm Hg), and the ratio of CL to CP was used to assess endothelial permeability at high lymph flows. There was little change in either QL (BL: 27 +/- 9; SI: 27 +/- 5 microliters/min) or CL/CP (BL: 0.76 +/- 0.03; SI: 0.74 +/- 0.02) after SI at normal Pla. Elevation of Pla caused a significant increase in QL (136 +/- 15 microliters/min), but CL/CP (0.67 +/- 0.02) failed to decrease significantly at high lymph flows. In group II (n = 15) total protein concentration of airway fluid was compared with that of plasma after smoke inhalation, intravenous alloxan, and increased Pla. The ratio of protein concentration in airway fluid to plasma after SI (0.70 +/- 0.07) was greater than that obtained with increased Pla (0.64 +/- 0.07) but less than that after alloxan (0.85 +/- 0.04). These data indicate that SI in the dog results in a moderate increase in pulmonary vascular permeability that is less severe than that induced by alloxan.

Nieman, G.F.; Clark, W.R. Jr.; Goyette, D.; Hart, A.K.; Bredenberg, C.E.

1989-04-01T23:59:59.000Z

263

The Metallicity of Galaxy Disks: Infall versus Outflow  

E-Print Network [OSTI]

Both gas accretion (infall) and winds (outflow) change a galaxy's metallicity and gas fraction, lowering the effective yield. Low effective yields in galaxies with rotation speeds 15% of baryons have been lost by galaxies of any mass. SN feedback is therefore unlikely to be effective for removing large amounts of gas from low mass disk galaxies. In addition, the dependence between metal-loss and galaxy mass is sufficiently weak that massive galaxies dominate metal enrichment of the IGM. The calculations in this paper provide limiting cases for any arbitrary chemical evolution history, as proven in an Appendix.

J. J. Dalcanton

2006-08-28T23:59:59.000Z

264

Gas permeability measurements for film envelope materials  

DOE Patents [OSTI]

Method and apparatus for measuring the permeability of polymer film materials such as used in super-insulation powder-filled evacuated panels (PEPs) reduce the time required for testing from several years to weeks or months. The method involves substitution of a solid non-outgassing body having a free volume of between 0% and 25% of its total volume for the usual powder in the PEP to control the free volume of the ``body-filled panel.`` Pressure versus time data for the test piece permit extrapolation to obtain long term performance of the candidate materials. 4 figs.

Ludtka, G.M.; Kollie, T.G.; Watkin, D.C.; Walton, D.G.

1998-05-12T23:59:59.000Z

265

Gas permeability measurements for film envelope materials  

DOE Patents [OSTI]

Method and apparatus for measuring the permeability of polymer film materials such as used in super-insulation powder-filled evacuated panels (PEPs) reduce the time required for testing from several years to weeks or months. The method involves substitution of a solid non-outgassing body having a free volume of between 0% and 25% of its total volume for the usual powder in the PEP to control the free volume of the "body-filled panel". Pressure versus time data for the test piece permit extrapolation to obtain long term performance of the candidate materials.

Ludtka, Gerard M. (Oak Ridge, TN); Kollie, Thomas G. (Oak Ridge, TN); Watkin, David C. (Clinton, TN); Walton, David G. (Knoxville, TN)

1998-01-01T23:59:59.000Z

266

Towards a characteristic equation for permeability  

E-Print Network [OSTI]

on a fractal-based derivation of permeability from porosity. The Pape et al. result is presented as an additive power law relation, typically of the form: k = a? + b? 2 + c? 10 . We do not believe that the Pape et al. model will find significant... utility in the petroleum industry, apart from unconsolidated materials and rocks of very uniform grain sizes. We do not wish to diminish the work of Pape et al. rather we just do not see the same behavior in our rock sample data (i.e., extremely well...

Siddiqui, Adil Ahmed

2008-10-10T23:59:59.000Z

267

Gas permeable electrode for electrochemical system  

DOE Patents [OSTI]

An electrode apparatus adapted for use in electrochemical systems having an anode compartment and a cathode compartment in which gas and ions are produced and consumed in the compartments during generation of electrical current. The electrode apparatus includes a membrane for separating the anode compartment from the cathode compartment wherein the membrane is permeable to both ions and gas. The cathode and anode for the assembly are provided on opposite sides of the membrane. During use of the membrane-electrode apparatus in electrochemical cells, the gas and ions generated at the cathode or anode migrate through the membrane to provide efficient transfer of gas and ions between the anode and cathode compartments.

Ludwig, Frank A. (Rancho Palos Verdes, CA); Townsend, Carl W. (Los Angeles, CA)

1989-01-01T23:59:59.000Z

268

Complications in Ankle Fracture Surgery.  

E-Print Network [OSTI]

??Mikko Ovaska. Complications in Ankle Fracture Surgery. Helsinki Bone and Joint Research Group, Department of Orthopaedic Surgery and Traumatology, Faculty of Medicine, University of Helsinki,… (more)

Ovaska, Mikko

2014-01-01T23:59:59.000Z

269

Fracture model for cemented aggregates  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

A mechanisms-based fracture model applicable to a broad class of cemented aggregates and, among them, plastic-bonded explosive (PBX) composites, is presented. The model is calibrated for PBX 9502 using the available experimental data under uniaxial compression and tension gathered at various strain rates and temperatures. We show that the model correctly captures inelastic stress-strain responses prior to the load peak and it predicts the post-critical macro-fracture processes, which result from the growth and coalescence of micro-cracks. In our approach, the fracture zone is embedded into elastic matrix and effectively weakens the material's strength along the plane of the dominant fracture.

Zubelewicz, Aleksander; Thompson, Darla G.; Ostoja-Starzewski, Martin; Ionita, Axinte; Shunk, Devin; Lewis, Matthew W.; Lawson, Joe C.; Kale, Sohan; Koric, Seid

2013-01-01T23:59:59.000Z

270

Seismic anisotropy of fractured rock  

E-Print Network [OSTI]

A comparison of the theory with recent ultra- sonic experiments on a simulated fractured medium .... Note that Poisson's ratio and Young's modulus for the.

M. Schoenberg, C. M. Sayers

2000-02-18T23:59:59.000Z

271

Coordinated studies in support of hydraulic fracturing of coalbed methane. Annual report, January 1993-April 1994  

SciTech Connect (OSTI)

The production of natural gas from coal typically requires stimulation in the form of hydraulic fracturing and, more recently, cavity completions. The results of hydraulic fracturing treatments have ranged from extremely successful to less than satisfactory. The purpose of this work is to characterize common and potential fracturing fluids in terms of coal-fluid interactions to identify reasons for less than satisfactory performance and to ultimately devise alternative fluids and treatment procedures to optimize production following hydraulic fracturing. The laboratory data reported herein has proven helpful in designing improved hydraulic fracturing treatments and remedial treatments in the Black Warrior Basin. Acid inhibitors, scale inhibitors, additives to improve coal relative permeability to gas, and non-damaging polymer systems for hydraulic fracturing have been screened in coal damage tests. The optimum conditions for creating field-like foams in the laboratory have been explored. Tests have been run to identify minimum polymer and surfactant concentrations for applications of foam in coal. The roll of 100 mesh sand in controlling leakoff and impairing conductivity in coal has been investigated. The leakoff and proppant transport of fluids with breaker has been investigated and recommendations have been made for breaker application to minimize damage potential in coal. A data base called COAL`S has been created in Paradox (trademark) for Windows to catalogue coalbed methane activities in the Black Warrior and San Juan Basins.

Penny, G.S.; Conway, M.W.

1994-08-01T23:59:59.000Z

272

Hydraulic interactions between fractures and bedding planes in a carbonate aquifer studied by means of experimentally induced water-table fluctuations (Coaraze  

E-Print Network [OSTI]

1 Hydraulic interactions between fractures and bedding planes in a carbonate aquifer studied high and low permeability regions are controlled by the hydraulic head gradient. Past studies have addressed this problem mainly considering steady- state hydraulic conditions. To study such exchanges during

Boyer, Edmond

273

FRACTURE ENHANCED SOIL VAPOR EXTRACTION TECHNOLOGY DEMONSTRATION AT THE A-014 OUTFALL  

SciTech Connect (OSTI)

Data collected during this study show that the performance of hydraulically fractured wells (with respect to mass removal rates) may tend to decrease with time following precipitation events. These effects are due to temporary increases in water saturation in the formation within the vicinity of the fractures, therefore, the wells should tend to rebound during subsequent dry periods. The data available for fractured well versus conventional well performance (with respect to flow rate versus vacuum pressure) are limited in this study. However, the data that we have to draw from suggest that, with the possible exception of a few extreme examples, hydraulically fractured wells tend to perform better than conventional wells during soil vapor extraction (SVE) operation at the A-14 Outfall. The pancake like geometry associated with hydraulic fractures also leads to a significant increase in zone of influence (ZOI), as compared to conventional wells. The increase in ZOI is due to the radially extending, horizontal, high-permeability conduit nature of the hydraulic fracture, however, air-flow into the fracture is predominately vertical (occurring at right angles to the fracture plane). Flow rates from above and below the fracture will tend to be equivalent when the formation is homogeneous, however, in the case of directionally fining depositional sequences flow rates will be greater from the direction of increasing permeability. The Upland Unit is a fining upward sequence, therefore flow rates (and contaminant mass flow rates) will tend to be higher below the fracture. This suggests that emplacing the fractures slightly above the source zone is an important strategy for accelerating contaminant removal at the A-014 Outfall site and in the Upland Unit at the SRS. However, due to the multitude of previous borings at the A-014 Outfall site, the shallower fractures failed. More than 2500 lbs of chlorinated volatile organic compounds (cVOCs) were removed during approximately 6 months of fractured well SVE operation at the A-014 field site. Plotting total mass removed over this time period shows a roughly linear relationship Figure 7. This occurs because the mass removal rate remains fairly constant with time. When mass removal comes predominately from cVOCs stored in the vapor phase there is a marked decline in mass removal rate over a short period of time due to the limiting nature of diffusion. Constant mass removal rates suggest that a source zone has been directly targeted and, therefore, is providing a constant supply of cVOC that partitions into the vapor phase and is removed through the well. Directly targeting and removing source zones is the most efficient approach to remediating contaminated sites. Results of this study show that utilization of hydraulic fractures during SVE is an effective approach for increasing remediation efficiency at the A-014 Outfall field site and in the Upland Unit at the SRS. Hydraulically fractured wells tend to produce greater flow rates and create larger ZOI's than do conventional wells. These attributes allow fractured wells to effectively treat larger volumes of formation. The unique sand-emplacement geometry associated with hydraulically fractured wells also allows direct targeting of multiple zones located at similar elevations within a fairly large radius of the well. The ability to directly target source zones significantly decreases diffusion pathways, therefore, significantly decreasing the time required to reach remediation goals.

Riha, B; Warren Hyde, W; Richard Hall (NOEMAIL), R

2008-03-12T23:59:59.000Z

274

Horizontal well will be employed in hydraulic fracturing research  

SciTech Connect (OSTI)

This paper reports on 10-well research site, planned to enable more controlled experiments for better definition of hydraulic fracturing. One of the 10 wells will be a near-horizontal well that will monitor microseismic events along its length. The Gas Research Institute (GR) has begun evaluating a low-permeability, gas-bearing sandstone as the target stratum for experiments to be conducted at its hydraulic fracture test site (HFTS). During a 4-year period, GRI will use the HFTS as a field laboratory to conduct multi-disciplinary research projects to assess the mechanics of hydraulic fracturing. As a result of a screening process the Davis sandstone in the Ft. Worth basin has emerged as the tight gas sand which best fits the selected criteria established by GRI and its contractors, GRI says. The Ft. Worth basin is located approximately 50 miles northwest of Ft. Worth. GRI is planning a research well to fully characterize the Davis prior to making a final decision on the location of the HFTS. If data from the research well indicate the Davis sand does not adequately meet selection criteria, other candidates identified in the screening process will be investigated.

Not Available

1991-05-20T23:59:59.000Z

275

Interferometric hydrofracture microseism localization using neighboring fracture  

E-Print Network [OSTI]

Hydraulic fracturing is the process of injecting high-pressure fluids into a reservoir to induce fractures and thus improve reservoir productivity. Microseismic event localization is used to locate created fractures. ...

Poliannikov, Oleg V.

2011-05-19T23:59:59.000Z

276

Interferometric hydrofracture microseism localization using neighboring fracture  

E-Print Network [OSTI]

Hydraulic fracturing is the process of injecting high-pressure fluids into a reservoir to induce fractures and thus improve reservoir productivity. Microseismic event localization is used to locate created fractures. ...

Poliannikov, Oleg V.

277

Fracture compliance estimation using borehole tube waves  

E-Print Network [OSTI]

We tested two models, one for tube-wave generation and the other for tube-wave attenuation at a fracture intersecting a borehole that can be used to estimate fracture compliance, fracture aperture, and lateral extent. In ...

Bakku, Sudhish Kumar

278

GEOLOGY AND FRACTURE SYSTEM AT STRIPA  

E-Print Network [OSTI]

1978. An Approach to the Fracture Hydrology at Stripa:Shanley. 1972. Analysis of Fracture Orientations for InputHydraulic Pro erties of Fractures by P. A. Witherspoon, C.

Olkiewicz, O.

2010-01-01T23:59:59.000Z

279

Highly porous aerogels of very low permeability *  

E-Print Network [OSTI]

In this paper, we firstly investigate the way the pores are created in silica gel during gelation. Then we show that the solid particle arrangement acts on the geometrical pore characteristics (pore volume and pore size distribution). According to the pore size value, the permeability of gels is quite low even if the value of the gel porosity exceeds 95%. Analogous properties can be extended to silica aerogels for which now the solvent is replaced by air. Consequently, and according to their low permeability, light weight aerogels exhibit very striking response to mechanical stresses. Here we report unusual experiments allowing us to estimate the mechanical properties of aerogels thanks to their low value of the average pore size. Moreover, one demonstrates that aerogels may be densified at room temperature using an external isostatic pressure. In that case, the pore size may be tailored with respect to the nature and the characteristics of the starting aerogel. The evolution of the textural properties such as the mean pore size and the specific surface area of these tailored aerogels is investigated as a function of isostatic pressure. 1.

J. Phalippou; T. Woignier; R. Sempéré; P. Dieudonné

280

Reservoir permeability from seismic attribute analysis  

SciTech Connect (OSTI)

In case of porous fluid-saturated medium the Biot's poroelasticity theory predicts a movement of the pore fluid relative to the skeleton on seismic wave propagation through the medium. This phenomenon opens an opportunity for investigation of the flow properties of the hydrocarbon-saturated reservoirs. It is well known that relative fluid movement becomes negligible at seismic frequencies if porous material is homogeneous and well cemented. In this case the theory predicts an underestimated seismic wave velocity dispersion and attenuation. Based on Biot's theory, Helle et al. (2003) have numerically demonstrated the substantial effects on both velocity and attenuation by heterogeneous permeability and saturation in the rocks. Besides fluid flow effect, the effects of scattering (Gurevich, et al., 1997) play very important role in case of finely layered porous rocks and heterogeneous fluid saturation. We have used both fluid flow and scattering effects to derive a frequency-dependent seismic attribute which is proportional to fluid mobility and applied it for analysis of reservoir permeability.

Silin, Dmitriy; Goloshubin, G.; Silin, D.; Vingalov, V.; Takkand, G.; Latfullin, M.

2008-02-15T23:59:59.000Z

Note: This page contains sample records for the topic "outflow fracture permeability" 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

Feedback from Protostellar Outflows in Star and Star Cluster Formation  

E-Print Network [OSTI]

Magnetic stresses collimate protostellar winds into a common distribution of force with angle. Sweeping into the ambient medium, such winds drive bipolar molecular outflows whose properties are insensitive to the distribution of ambient gas and to the details of how the wind is launched, and how its intensity varies over time. Moreover, these properties are in accord with the commonly observed features of outflows. This model is simple enough to permit a quantitative study of the feedback effects from low-mass star formation. It predicts the rate at which star-forming gas is ejected by winds, and hence the efficiency with which stars form. Applied to individual star formation, it relates the stellar initial mass function to the distribution of pre-stellar cores. Applied to cluster formation, it indicates whether the resulting stellar system will remain gravitationally bound. Using the energy injection and mass ejection implied by this model, we investigate the dynamical evolution of a molecular clump as a stellar cluster forms within it. This depends critically on the rate at which turbulence decays: it may involve equilibrium star formation (slow decay), overstable oscillations, or collapse (fast decay).

Christopher D. Matzner

2000-07-13T23:59:59.000Z

282

Impacts of pure shocks in the BHR71 bipolar outflow  

E-Print Network [OSTI]

During the formation of a star, material is ejected along powerful jets that impact the ambient material. This outflow regulates star formation by e.g. inducing turbulence and heating the surrounding gas. Understanding the associated shocks is therefore essential to the study of star formation. We present comparisons of shock models with CO, H2, and SiO observations in a 'pure' shock position in the BHR71 bipolar outflow. These comparisons provide an insight into the shock and pre-shock characteristics, and allow us to understand the energetic and chemical feedback of star formation on Galactic scales. New CO (Jup = 16, 11, 7, 6, 4, 3) observations from the shocked regions with the SOFIA and APEX telescopes are presented and combined with earlier H2 and SiO data (from the Spitzer and APEX telescopes). The integrated intensities are compared to a grid of models that were obtained from a magneto-hydrodynamical shock code which calculates the dynamical and chemical structure of these regions combined with a radi...

Gusdorf, Antoine; Anderl, Sibylle; Eisloeffel, Jochen; Codella, Claudio; Gomez-Ruiz, Arturo; Graf, Urs; Kristensen, Lars; Leurini, Silvia; Parise, Berengere; Requena-Torres, Migel; Ricken, Oliver; Guesten, Rolf

2015-01-01T23:59:59.000Z

283

Condensation of MgS in outflows from carbon stars  

E-Print Network [OSTI]

The basic mechanism responsible for the widespread condensation of MgS in the outflows from carbon rich stars on the tip of the AGB is discussed with the aim of developing a condensation model that can be applied in model calculations of dust formation in stellar winds. The different possibilities how MgS may be formed in the chemical environment of outflows from carbon stars are explored by some thermochemical calculations and by a detailed analysis of the growth kinetics of grains in stellar winds. The optical properties of core-mantle grains with a MgS mantle are calculated to demonstrate that such grains reproduce the structure of the observed 30 $\\mu$m feature. These considerations are complemented by model calculations of circumstellar dust shells around carbon stars. It is argued that MgS is formed via precipitation on silicon carbide grains. This formation mechanism explains some of the basic observed features of MgS condensation in dust shells around carbon stars. A weak secondary peak at about 33 ... 36 $\\mu$m is shown to exist in certain cases if MgS forms a coating on SiC.

Svitlana Zhukovska; Hans-Peter Gail

2008-03-20T23:59:59.000Z

284

Filaments, Collapse and Outflows in Massive Star Formation  

E-Print Network [OSTI]

We present results from our numerical simulations of collapsing massive molecular cloud cores. These numerical calculations show that massive stars assemble quickly with mass accretion rates exceeding 10^-3 Msol/yr and confirm that the mass accretion during the collapsing phase is much more efficient than predicted by selfsimilar collapse solutions, dM/dt ~ c^3/G. We find that during protostellar assembly out of a non-turbulent core, the mass accretion reaches 20 - 100 c^3/G. Furthermore, we explore the self-consistent structure of bipolar outflows that are produced in our three dimensional magnetized collapse simulations. These outflows produce cavities out of which radiation pressure can be released, thereby reducing the limitations on the final mass of massive stars formed by gravitational collapse. Additional enhancement of the mass accretion rate comes from accretion along filaments that are built up by supersonic turbulent motions. Our numerical calculations of collapsing turbulent cores result in mass accretion rates as high as 10^-2 Msol/yr.

Robi Banerjee; Ralph E. Pudritz

2008-07-04T23:59:59.000Z

285

Massive disk outflows mediated by extreme magnetic fields  

E-Print Network [OSTI]

We argue that magnetic fields amplified within a very high accretion-rate disk around main sequence stars can lead to the formation of massive bipolar outflows that can remove most of the disk's mass and energy. This efficient directional removal of energy and mass allows the high accretion-rate disk to be built. We construct thick disks where the magnetic fields are amplified by an Alpha-Omega dynamo in the disk, bringing the fluctuating components of the magnetic field to be much stronger than the large-scale component. By examining the possible activity of the magnetic fields we conclude that main sequence stars can accrete mass at very high rates, up to 0.01Mo/yr for solar type stars, and up to 1Mo/yr for very massive stars. Such energetic outflows can account for the powering of some eruptive objects, such as merging main sequence stars, major eruptions of luminous blue variables, such as the Great Eruption of Eta Carinae, and other intermediate luminosity optical transients (ILOTs; Red Novae; Red Transi...

Shiber, Sagiv; Soker, Noam

2015-01-01T23:59:59.000Z

286

ULTRAFAST OUTFLOWS: GALAXY-SCALE ACTIVE GALACTIC NUCLEUS FEEDBACK  

SciTech Connect (OSTI)

We show, using global three-dimensional grid-based hydrodynamical simulations, that ultrafast outflows (UFOs) from active galactic nuclei (AGNs) result in considerable feedback of energy and momentum into the interstellar medium (ISM) of the host galaxy. The AGN wind interacts strongly with the inhomogeneous, two-phase ISM consisting of dense clouds embedded in a tenuous, hot, hydrostatic medium. The outflow floods through the intercloud channels, sweeps up the hot ISM, and ablates and disperses the dense clouds. The momentum of the UFO is primarily transferred to the dense clouds via the ram pressure in the channel flow, and the wind-blown bubble evolves in the energy-driven regime. Any dependence on UFO opening angle disappears after the first interaction with obstructing clouds. On kpc scales, therefore, feedback by UFOs operates similarly to feedback by relativistic AGN jets. Negative feedback is significantly stronger if clouds are distributed spherically rather than in a disk. In the latter case, the turbulent backflow of the wind drives mass inflow toward the central black hole. Considering the common occurrence of UFOs in AGNs, they are likely to be important in the cosmological feedback cycles of galaxy formation.

Wagner, A. Y.; Umemura, M. [Center for Computational Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577 (Japan); Bicknell, G. V., E-mail: ayw@ccs.tsukuba.ac.jp [Research School of Astronomy and Astrophysics, Australian National University, ACT 2611 (Australia)

2013-01-20T23:59:59.000Z

287

The Water Vapor Abundance in Orion KL Outflows  

E-Print Network [OSTI]

We present the detection and modeling of more than 70 far-IR pure rotational lines of water vapor, including the 18O and 17O isotopologues, towards Orion KL. Observations were performed with the Long Wavelength Spectrometer Fabry-Perot (LWS/FP; R~6800-9700) on board the Infrared Space Observatory (ISO) between ~43 and ~197 um. The water line profiles evolve from P-Cygni type profiles (even for the H2O18 lines) to pure emission at wavelengths above ~100 um. We find that most of the water emission/absorption arises from an extended flow of gas expanding at 25+-5 kms^-1. Non-local radiative transfer models show that much of the water excitation and line profile formation is driven by the dust continuum emission. The derived beam averaged water abundance is 2-3x10^-5. The inferred gas temperature Tk=80-100 K suggests that: (i) water could have been formed in the "plateau" by gas phase neutral-neutral reactions with activation barriers if the gas was previously heated (e.g. by shocks) to >500 K and/or (ii) H2O formation in the outflow is dominated by in-situ evaporation of grain water-ice mantles and/or (iii) H2O was formed in the innermost and warmer regions (e.g. the hot core) and was swept up in ~1000 yr, the dynamical timescale of the outflow.

J. Cernicharo; J. R. Goicoechea; F. Daniel; M. R. Lerate; M. J. Barlow; B. M. Swinyard; E. van Dishoeck; T. L. Lim; S. Viti; J. Yates

2006-08-16T23:59:59.000Z

288

Variability of the NGC 1333 IRAS 4A Outflow: Molecular Hydrogen and Silicon Monoxide Images  

E-Print Network [OSTI]

The NGC 1333 region was observed in the H2 1-0 S(1) line. The H2 images cover a 5' x 7' region around IRAS 4. Numerous H2 emission features were detected. The northeast-southwest bipolar outflow driven by IRAS 4A was studied by combining the H2 images with SiO maps published previously. The SiO-H2 outflows are continuous on the southwestern side but show a gap on the northeastern side. The southwestern outflow lobe curves smoothly, and the position angle increases with the distance from the driving source. The base and the outer tip of the northeastern outflow lobe are located at positions opposite to the corresponding parts of the southwestern lobe. This point-symmetry suggests that the outflow axis may be drifting or precessing clockwise in the plane of the sky and that the cause of the axis drift may be intrinsic to the outflow engine. The axis drift model is supported by the asymmetric lateral intensity profile of the SiO outflow. The axis drift rate is about 0.011 deg yr-1. The middle part of the northeastern outflow does not exactly follow the point symmetry because of the superposition of two different kinds of directional variability: the axis drift of the driving source and the deflection by a dense core. The axis drift model provides a good explanation for the large deflection angle of the northeastern outflow. Other H2 emission features around the IRAS 4 region are discussed briefly. Some of them are newly found outflows, and some are associated with outflows already known before.

Minho Choi; Klaus W. Hodapp; Masahiko Hayashi; Kentaro Motohara; Soojong Pak; Tae-Soo Pyo

2006-04-19T23:59:59.000Z

289

Calculation of large scale relative permeabilities from stochastic properties of the permeability field and fluid properties  

SciTech Connect (OSTI)

The paper describes the method and presents preliminary results for the calculation of homogenized relative permeabilities using stochastic properties of the permeability field. In heterogeneous media, the spreading of an injected fluid is mainly sue to the permeability heterogeneity and viscosity fingering. At large scale, when the heterogeneous medium is replaced by a homogeneous one, we need to introduce a homogenized (or pseudo) relative permeability to obtain the same spreading. Generally, is derived by using fine-grid numerical simulations (Kyte and Berry). However, this operation is time consuming and cannot be performed for all the meshes of the reservoir. We propose an alternate method which uses the information given by the stochastic properties of the field without any numerical simulation. The method is based on recent developments on homogenized transport equations (the {open_quotes}MHD{close_quotes} equation, Lenormand SPE 30797). The MHD equation accounts for the three basic mechanisms of spreading of the injected fluid: (1) Dispersive spreading due to small scale randomness, characterized by a macrodispersion coefficient D. (2) Convective spreading due to large scale heterogeneities (layers) characterized by a heterogeneity factor H. (3) Viscous fingering characterized by an apparent viscosity ration M. In the paper, we first derive the parameters D and H as functions of variance and correlation length of the permeability field. The results are shown to be in good agreement with fine-grid simulations. The are then derived a function of D, H and M. The main result is that this approach lead to a time dependent . Finally, the calculated are compared to the values derived by history matching using fine-grid numerical simulations.

Lenormand, R.; Thiele, M.R. [Institut Francais du Petrole, Rueil Malmaison (France)

1997-08-01T23:59:59.000Z

290

Stress-dependent permeability on tight gas reservoirs.  

E-Print Network [OSTI]

??People in the oil and gas industry sometimes do not consider pressure-dependent permeability in reservoir performance calculations. It basically happens due to lack of lab… (more)

Rodriguez, Cesar Alexander

2005-01-01T23:59:59.000Z

291

astrocyte water permeability: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

19 Predicting relative permeability from water retention: A direct approach based on fractal geometry Environmental Management and Restoration Websites Summary: curves (e.g.,...

292

Exploring the physicochemical processes that govern hydraulic fracture through laboratory  

E-Print Network [OSTI]

) containing model boreholes as an analog to hydraulic fracturing with various fracture-driving fluids. The

Belmonte A; Connelly P

293

Seismic Fracture Characterization Methods for Enhanced Geothermal...  

Broader source: Energy.gov (indexed) [DOE]

Seismic Fracture Characterization Methods for Enhanced Geothermal Systems Principal Investigator: John H. Queen Hi-Q Geophysical Inc. Track Name: Seismicity and Reservoir Fracture...

294

Mechanics of layered anisotropic poroelastic media with applications to effective stress for fluid permeability  

SciTech Connect (OSTI)

The mechanics of vertically layered porous media has some similarities to and some differences from the more typical layered analysis for purely elastic media. Assuming welded solid contact at the solid-solid interfaces implies the usual continuity conditions, which are continuity of the vertical (layering direction) stress components and the horizontal strain components. These conditions are valid for both elastic and poroelastic media. Differences arise through the conditions for the pore pressure and the increment of fluid content in the context of fluid-saturated porous media. The two distinct conditions most often considered between any pair of contiguous layers are: (1) an undrained fluid condition at the interface, meaning that the increment of fluid content is zero (i.e., {delta}{zeta} = 0), or (2) fluid pressure continuity at the interface, implying that the change in fluid pressure is zero across the interface (i.e., {delta}p{sub f} = 0). Depending on the types of measurements being made on the system and the pertinent boundary conditions for these measurements, either (or neither) of these two conditions might be directly pertinent. But these conditions are sufficient nevertheless to be used as thought experiments to determine the expected values of all the poroelastic coefficients. For quasi-static mechanical changes over long time periods, we expect drained conditions to hold, so the pressure must then be continuous. For high frequency wave propagation, the pore-fluid typically acts as if it were undrained (or very nearly so), with vanishing of the fluid increment at the boundaries being appropriate. Poroelastic analysis of both these end-member cases is discussed, and the general equations for a variety of applications to heterogeneous porous media are developed. In particular, effective stress for the fluid permeability of such poroelastic systems is considered; fluid permeabilities characteristic of granular media or tubular pore shapes are treated in some detail, as are permeabilities of some of the simpler types of fractured materials.

Berryman, J.G.

2010-06-01T23:59:59.000Z

295

Influence of Sea Surface Temperature on Humidity and Temperature in the Outflow of Tropical Deep Convection  

E-Print Network [OSTI]

-Service Aircraft (MOZAIC) project are analyzed in the vicinity of deep convective outflow to study the variationsInfluence of Sea Surface Temperature on Humidity and Temperature in the Outflow of Tropical Deep upper-tropospheric temperature and humidity by the Mea- surement of Ozone and Water Vapor by Airbus In

Johnson, Richard H.

296

The Near-Infrared Tracks of Protostellar Outflows. A thesis submitted for the degree of  

E-Print Network [OSTI]

The Near-Infrared Tracks of Protostellar Outflows. A thesis submitted for the degree of Doctor of objects are described. In each case, the technique of near-infrared imaging is used in order to understand designed to study examples of very bright outflows in the near-infrared using the UFTI high

297

Transport pathways for Asian pollution outflow over the Pacific: Interannual and seasonal variations  

E-Print Network [OSTI]

Meteorology and Atmospheric Dynamics: Synoptic-scale meteorology; KEYWORDS: pollution transport, outflow emissions and of the export of Asian pollution to the global atmosphere. This was one of the majorTransport pathways for Asian pollution outflow over the Pacific: Interannual and seasonal

Liu, Hongyu

298

Neutrino Interactions in the Outflow from Gamma-Ray Burst Accretion Disks  

E-Print Network [OSTI]

We examine the composition of matter as it flows away from gamma ray burst accretion disks, in order to determine what sort of nucleosynthesis may occur. Since there is a large flux of neutrinos leaving the surface of the disk, the electron fraction of the outflowing material will change due to charged current neutrino interactions. We calculate the electron fraction in the wind using detailed neutrino fluxes from every point on the disk and study a range of trajectories and outflow conditions for several different accretion disk models. We find that low electron fractions, conducive to making r-process elements, only appear in outflows from disks with high accretion rates that have a significant region both of trapped neutrinos and antineutrinos. Disks with lower accretion rates that have only a significant region of trapped neutrinos can have outflows with very high electron fractions, whereas the lowest accretion rate disks with little trapping have outflow electrons fractions of closer to one half.

R. Surman; G. C. McLaughlin

2004-07-09T23:59:59.000Z

299

Gas permeable electrode for electrochemical system  

DOE Patents [OSTI]

An electrode apparatus is described which is adapted for use in electrochemical systems having an anode compartment and a cathode compartment in which gas and ions are produced and consumed in the compartments during generation of electrical current. The electrode apparatus includes a membrane for separating the anode compartment from the cathode compartment wherein the membrane is permeable to both ions and gas. The cathode and anode for the assembly are provided on opposite sides of the membrane. During use of the membrane-electrode apparatus in electrochemical cells, the gas and ions generated at the cathode or anode migrate through the membrane to provide efficient transfer of gas and ions between the anode and cathode compartments. 3 figs.

Ludwig, F.A.; Townsend, C.W.

1989-09-12T23:59:59.000Z

300

Fluid permeability measurement system and method  

DOE Patents [OSTI]

A system for measuring the permeance of a material. The permeability of the material may also be derived. The system provides a liquid or high concentration fluid bath on one side of a material test sample, and a gas flow across the opposing side of the material test sample. The mass flow rate of permeated fluid as a fraction of the combined mass flow rate of gas and permeated fluid is used to calculate the permeance of the material. The material test sample may be a sheet, a tube, or a solid shape. Operational test conditions may be varied, including concentration of the fluid, temperature of the fluid, strain profile of the material test sample, and differential pressure across the material test sample.

Hallman, Jr., Russell Louis (Knoxville, TN); Renner, Michael John (Oak Ridge, TN)

2008-02-05T23:59:59.000Z

Note: This page contains sample records for the topic "outflow fracture permeability" 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

NUCLEOSYNTHESIS IN THE OUTFLOWS ASSOCIATED WITH ACCRETION DISKS OF TYPE II COLLAPSARS  

SciTech Connect (OSTI)

We investigate nucleosynthesis inside the outflows from gamma-ray burst (GRB) accretion disks formed by the Type II collapsars. In these collapsars, massive stars undergo core collapse to form a proto-neutron star initially, and a mild supernova (SN) explosion is driven. The SN ejecta lack momentum, and subsequently this newly formed neutron star gets transformed to a stellar mass black hole via massive fallback. The hydrodynamics and the nucleosynthesis in these accretion disks have been studied extensively in the past. Several heavy elements are synthesized in the disk, and much of these heavy elements are ejected from the disk via winds and outflows. We study nucleosynthesis in the outflows launched from these disks by using an adiabatic, spherically expanding outflow model, to understand which of these elements thus synthesized in the disk survive in the outflow. While studying this, we find that many new elements like isotopes of titanium, copper, zinc, etc., are present in the outflows. {sup 56}Ni is abundantly synthesized in most of the cases in the outflow, which implies that the outflows from these disks in a majority of cases will lead to an observable SN explosion. It is mainly present when outflow is considered from the He-rich, {sup 56}Ni/{sup 54}Fe-rich zones of the disks. However, outflow from the Si-rich zone of the disk remains rich in silicon. Although emission lines of many of these heavy elements have been observed in the X-ray afterglows of several GRBs by Chandra, BeppoSAX, XMM-Newton, etc., Swift seems to have not yet detected these lines.

Banerjee, Indrani; Mukhopadhyay, Banibrata, E-mail: indrani@physics.iisc.ernet.in, E-mail: bm@physics.iisc.ernet.in [Department of Physics, Indian Institute of Science, Bangalore 560 012 (India)

2013-11-20T23:59:59.000Z

302

Consolidation and permeability of salt in brine  

SciTech Connect (OSTI)

The consolidation and loss of permeability of salt crystal aggregates, important in assessing the effects of water in salt repositories, has been studied as a function of several variables. The kinetic behavior was similar to that often observed in sintering and suggested the following expression for the time dependence of the void fraction: phi(t) = phi(0) - (A/B)ln(1 + Bt/z(0)/sup 3/), where A and B are rate constants and z(0) is initial average particle size. With brine present, A and phi(0) varied linearly with stress. The initial void fraction was also dependent to some extent on the particle size distribution. The rate of consolidation was most rapid in brine and least rapid in the presence of only air as the fluid. A brine containing 5 m MgCl/sub 2/ showed an intermediate rate, presumably because of the greatly reduced solubility of NaCl. A substantial wall effect was indicated by an observed increase in the void fraction of consolidated columns with distance from the top where the stress was applied and by a dependence of consolidation rate on the column height and radius. The distance through which the stress fell by a factor of phi was estimated to change inversely as the fourth power of the column diameter. With increasing temperature (to 85/sup 0/C), consolidation proceeded somewhat more rapidly and the wall effect was reduced. The permeability of the columns dropped rapidly with consolidation, decreasing with about the sixth power of the void fraction. In general, extrapolation of the results to repository conditions confirms the self-sealing properties of bedded salt as a storage medium for radioactive waste.

Shor, A.J.; Baes, C.F. Jr.; Canonico, C.M.

1981-07-01T23:59:59.000Z

303

Hydraulic Permeability of Resorcinol-Formaldehyde Resin  

SciTech Connect (OSTI)

An ion exchange process using spherical resorcinol-formaldehyde (RF) resin is the baseline process for removing cesium from the dissolved salt solution in the high-level waste tanks at the Hanford Site, using large scale columns as part of the Waste Treatment Plant (WTP). The RF resin is also being evaluated for use in the proposed small column ion exchange (SCIX) system, which is an alternative treatment option at Hanford and at the Savannah River Site (SRS). A recirculating test loop with a small ion exchange column was used to measure the effect of oxygen uptake and radiation exposure on the permeability of a packed bed of the RF resin. The lab-scale column was designed to be prototypic of the proposed Hanford columns at the WTP. Although the test equipment was designed to model the Hanford ion exchange columns, the data on changes in the hydraulic permeability of the resin will also be valuable for determining potential pressure drops through the proposed SCIX system. The superficial fluid velocity in the lab-scale test (3.4-5.7 cm/s) was much higher than is planned for the full-scale Hanford columns to generate the maximum pressure drop expected in those columns (9.7 psig). The frictional drag from this high velocity produced forces on the resin in the lab-scale tests that matched the design basis of the full-scale Hanford column. Any changes in the resin caused by the radiation exposure and oxygen uptake were monitored by measuring the pressure drop through the lab-scale column and the physical properties of the resin. Three hydraulic test runs were completed, the first using fresh RF resin at 25 C, the second using irradiated resin at 25 C, and the third using irradiated resin at 45 C. A Hanford AP-101 simulant solution was recirculated through a test column containing 500 mL of Na-form RF resin. Known amounts of oxygen were introduced into the primary recirculation loop by saturating measured volumes of the simulant solution with oxygen and reintroducing the oxygenated simulant into the feed tank. The dissolved oxygen (DO) concentration of the recirculating simulant was monitored, and the amount of oxygen that reacted with the resin was determined from the change in the DO concentration of the recirculating simulant solution. Prior to hydraulic testing the resin for runs 2 and 3 was covered with the simulant solution and irradiated in a spent fuel element at the Oak Ridge National Laboratory High Flux Isotope Reactor (HFIR). Both batches of resin were irradiated to a total gamma dose of 177 Mrad, but the resin for run 2 reached a maximum temperature during irradiation of 51 C, while the resin for run 3 reached a temperature of 38 C. The different temperatures were the result of the operating status of HFIR at the time of the irradiation and were not part of the test plan; however, the results clearly show the impact of the higher-temperature exposure during irradiation. The flow rate and pressure drop data from the test loop runs show that irradiating the RF resin reduces both the void fraction and the permeability of the resin bed. The mechanism for the reduction in permeability is not clear because irradiation increases the particle size of the resin beads and makes them deform less under pressure. Microscopic examination of the resin beads shows that they are all smooth regular spheres and that irradiation or oxygen uptake did not change the shape of the beads. The resin reacts rapidly with DO in the simulant solution, and the reaction with oxygen reduces the permeability of a bed of new resin by about 10% but has less impact on the permeability of irradiated resin. Irradiation increases the toughness of the resin beads, probably by initiating cross-linking reactions in them. Oxygen uptake reduces the crush strength of both new and irradiated resin; however, the pressures that caused the beads to crush are much higher than would be expected during the operation of an ion exchange column. There was no visible evidence of broken beads in any of the resin samples taken from the test loop. Reaction with oxygen red

Taylor, Paul Allen [ORNL

2010-01-01T23:59:59.000Z

304

Permeability of Connexin Channels Andrew L. Harris and Darren Locke  

E-Print Network [OSTI]

Chapter 7 Permeability of Connexin Channels Andrew L. Harris and Darren Locke Abstract Because Molecular permeability Á Second messengers A.L. Harris (*) Department of Pharmacology and Physiology, New, Newark, NJ 07103, United States e-mail: aharris@umdnj.edu A. Harris, D. Locke (eds.), Connexins: A Guide

Harris, Andrew L.

305

Tailoring The Microwave Permittivity And Permeability Of Composite Materials  

E-Print Network [OSTI]

1 Tailoring The Microwave Permittivity And Permeability Of Composite Materials Kenneth M. Bober/Lowell, Lowell, MA 01854 ABSTRACT The microwave permittivity( r ) and permeability( r ) of composite materials. Polynomials are also used for the ferrite composites because it was determined that the MG theory was unable

Massachusetts at Lowell, University of

306

Determination of Coal Permeability Using Pressure Transient Methods  

SciTech Connect (OSTI)

Coalbed methane is a significant natural resource in the Appalachian region. It is believed that coalbed methane production can be enhanced by injection of carbon dioxide into coalbeds. However, the influence of carbon dioxide injection on coal permeability is not yet well understood. Competitive sorption of carbon dioxide and methane gases onto coal is a known process. Laboratory experiments and limited field experience indicate that coal will swell during sorption of a gas and shrink during desorption of a gas. The swelling and shrinkage may change the permeability of the coal. In this study, the permeability of coal was determined by using carbon dioxide as the flowing fluid. Coal samples with different dimensions were prepared for laboratory permeability tests. Carbon dioxide was injected into the coal and the permeability was determined by using pressure transient methods. The confining pressure was variedto cover a wide range of depths. The permeability was also determined as a function of exposure time of carbon dioxide while the confining stress was kept constant. CT scans were taken before and after the introduction of carbon dioxide. Results show that the porosity and permeability of the coal matrix was very low. The paper presents experimental data and theoretical aspects of the flow of carbon dioxide through a coal sample during pressure transient tests. The suitability of the pressure transient methods for determining permeability of coal during carbon dioxide injection is discussed in the paper.

McLendon, T.R.; Siriwardane, H. (West Virginia University, Morgantown, WV); Haljasmaa, I.V.; Bromhal, G.S.; Soong, Y.; Irdi, G.A.

2007-05-01T23:59:59.000Z

307

Hydrogen-permeable composite metal membrane and uses thereof  

DOE Patents [OSTI]

Various hydrogen production and hydrogen sulfide decomposition processes are disclosed that utilize composite metal membranes that contain an intermetallic diffusion barrier separating a hydrogen-permeable base metal and a hydrogen-permeable coating metal. The barrier is a thermally stable inorganic proton conductor.

Edlund, David J. (Bend, OR); Friesen, Dwayne T. (Bend, OR)

1993-06-08T23:59:59.000Z

308

EXPERIMENTAL MEASUREMENT OF STEAM-WATER RELATIVE PERMEABILITY  

E-Print Network [OSTI]

EXPERIMENTAL MEASUREMENT OF STEAM-WATER RELATIVE PERMEABILITY A REPORT SUBMITTED TO THE DEPARTMENT calculations. X-ray computer tomography (CT) aided by measuring in-situ steam saturation more directly. The measured steam-water relative permeability curves assume a shape similar to those obtained by Corey (1954

Stanford University

309

Powerful Outflows and Feedback from Active Galactic Nuclei  

E-Print Network [OSTI]

Active Galactic Nuclei (AGN) represent the growth phases of the supermassive black holes in the center of almost every galaxy. Powerful, highly ionized winds, with velocities $\\sim 0.1- 0.2c$ are a common feature in X--ray spectra of luminous AGN, offering a plausible physical origin for the well known connections between the hole and properties of its host. Observability constraints suggest that the winds must be episodic, and detectable only for a few percent of their lifetimes. The most powerful wind feedback, establishing the $M -\\sigma$ relation, is probably not directly observable at all. The $M - \\sigma$ relation signals a global change in the nature of AGN feedback. At black hole masses below $M-\\sigma$ feedback is confined to the immediate vicinity of the hole. At the $M-\\sigma$ mass it becomes much more energetic and widespread, and can drive away much of the bulge gas as a fast molecular outflow.

King, Andrew

2015-01-01T23:59:59.000Z

310

Predicting the spatial extent of injection-induced zones of enhanced permeability at the Northwest Geysers EGS Demonstration Project  

E-Print Network [OSTI]

not traditional hydraulic fracturing or fracture stimulationfar below the hydraulic fracturing pressure. The injectionpressure to avoid hydraulic fracturing, but aims at dilating

Rutqvist, J.

2010-01-01T23:59:59.000Z

311

Fracture of synthetic diamond M. D. Droty  

E-Print Network [OSTI]

Fracture of synthetic diamond M. D. Droty Ctystallume, 3506 Bassett Street, Santa Clara, California 1995) The fracture behavior of synthetic diamond has been investigated using indentation methods and by the tensile testing of pre-notched fracture-mechanics type samples. Specifically, the fracture toughness

Ritchie, Robert

312

Microstructure-Properties: IMicrostructure-Properties: I Lecture 6A: FractureLecture 6A: Fracture  

E-Print Network [OSTI]

-Properties: IMicrostructure-Properties: I Lecture 6A: FractureLecture 6A: Fracture 27-301 Fall, 2007 Prof. A. D. Rollett the fracture resistance of materials to their microstructure. · Both ceramics and metals exhibit strongly microstructure dependent fracture resistance. · This section focuses on basic theory of brittle fracture

Rollett, Anthony D.

313

Critical Fracture Stress and Fracture Strain Models for the Prediction of Lower and  

E-Print Network [OSTI]

Critical Fracture Stress and Fracture Strain Models for the Prediction of Lower and Upper Shelf fracture stress and stress modified fracture strain models are utilized to describe the variation of lower and upper shelf fracture toughness with temperature and strain rate for two alloy steels used

Ritchie, Robert

314

Journal of Biomechanics 38 (2005) 15171525 Fracture in human cortical bone: local fracture criteria and  

E-Print Network [OSTI]

Journal of Biomechanics 38 (2005) 1517­1525 Fracture in human cortical bone: local fracture, Livermore, CA 94550 Accepted 19 July 2004 Abstract Micromechanical models for fracture initiation such micromechanical models have been developed for the fracture of bone. In fact, although the fracture event

Ritchie, Robert O.

315

Characterization of EGS Fracture Network Lifecycles  

SciTech Connect (OSTI)

Geothermal energy is relatively clean, and is an important non-hydrocarbon source of energy. It can potentially reduce our dependence on fossil fuels and contribute to reduction in carbon emissions. High-temperature geothermal areas can be used for electricity generation if they contain permeable reservoirs of hot water or steam that can be extracted. The biggest challenge to achieving the full potential of the nation’s resources of this kind is maintaining and creating the fracture networks required for the circulation, heating, and extraction of hot fluids. The fundamental objective of the present research was to understand how fracture networks are created in hydraulic borehole injection experiments, and how they subsequently evolve. When high-pressure fluids are injected into boreholes in geothermal areas, they flow into hot rock at depth inducing thermal cracking and activating critically stressed pre-existing faults. This causes earthquake activity which, if monitored, can provide information on the locations of the cracks formed, their time-development and the type of cracking underway, e.g., whether shear movement on faults occurred or whether cracks opened up. Ultimately it may be possible to monitor the critical earthquake parameters in near-real-time so the information can be used to guide the hydraulic injection while it is in progress, e.g., how to adjust factors such as injectate pressure, volume and temperature. In order to achieve this, it is necessary to mature analysis techniques and software that were, at the start of this project, in an embryonic developmental state. Task 1 of the present project was to develop state-of-the-art techniques and software for calculating highly accurate earthquake locations, earthquake source mechanisms (moment tensors) and temporal changes in reservoir structure. Task 2 was to apply the new techniques to hydrofracturing (Enhanced Geothermal Systems, or “EGS”) experiments performed at the Coso geothermal field, in order to enhance productivity there. Task 3 was to interpret the results jointly with other geological information in order to provide a consistent physical model. All of the original goals of the project have been achieved. An existing program for calculating accurate relative earthquake locations has been enhanced by a technique to improve the accuracy of earthquake arrival-time measurements using waveform cross-correlation. Error analysis has been added to pre-existing moment tensor software. New seismic tomography software has been written to calculate changes in structure that could be due, for example, to reservoir depletion. Data processing procedures have been streamlined and web tools developed for rapid dissemination of the results, e.g., to on-site operations staff. Application of the new analysis tools to the Coso geothermal field has demonstrated the effective use of the techniques and provided important case histories to guide the style of future applications. Changes in reservoir structure with time are imaged throughout the upper 3 km, identifying the areas where large volumes of fluid are being extracted. EGS hydrofracturing experiments in two wells stimulated a nearby fault to the south that ruptured from south to north. The position of this fault could be precisely mapped and its existence was confirmed by surface mapping and data from a borehole televiewer log. No earthquakes occurred far north of the injection wells, suggesting that the wells lie near the northern boundary of the region of critically stressed faults. Minor en-echelon faults were also activated. Significant across-strike fluid flow occurred. The faults activated had significant crack-opening components, indicating that the hydraulic fracturing created open cavities at depth. The fluid injection changed the local stress field orientation and thus the mode of failure was different from the normal background. Initial indications are that the injections modulated stress release, seismicity and natural fracture system evolution for periods of up to months. The research demon

Gillian R. Foulger

2008-03-31T23:59:59.000Z

316

Variability of the NGC 1333 IRAS 4A Outflow: Molecular Hydrogen and Silicon Monoxide Images  

E-Print Network [OSTI]

The NGC 1333 region was observed in the H2 1-0 S(1) line. The H2 images cover a 5' x 7' region around IRAS 4. Numerous H2 emission features were detected. The northeast-southwest bipolar outflow driven by IRAS 4A was studied by combining the H2 images with SiO maps published previously. The SiO-H2 outflows are continuous on the southwestern side but show a gap on the northeastern side. The southwestern outflow lobe curves smoothly, and the position angle increases with the distance from the driving source. The base and the outer tip of the northeastern outflow lobe are located at positions opposite to the corresponding parts of the southwestern lobe. This point-symmetry suggests that the outflow axis may be drifting or precessing clockwise in the plane of the sky and that the cause of the axis drift may be intrinsic to the outflow engine. The axis drift model is supported by the asymmetric lateral intensity profile of the SiO outflow. The axis drift rate is about 0.011 deg yr-1. The middle part of the northea...

Choi, M; Hayashi, M; Motohara, K; Pak, S; Pyo, T S; Choi, Minho; Hodapp, Klaus W.; Hayashi, Masahiko; Motohara, Kentaro; Pak, Soojong; Pyo, Tae-Soo

2006-01-01T23:59:59.000Z

317

Sensitivity analysis of fracture scattering  

E-Print Network [OSTI]

We use a 2-D finite difference method to numerically calculate the seismic response of a single finite fracture in a homogeneous media. In our experiments, we use a point explosive source and ignore the free surface effect, ...

Fang, Xinding, S.M. Massachusetts Institute of Technology

2010-01-01T23:59:59.000Z

318

Optimization of fracture treatment designs  

E-Print Network [OSTI]

length and fracture conductivity, and well spacing to optimize methane recovery and project economics of coalbed methane reservoirs. Anderson and Philflps g examined several methods of optimizing proppant selection. Proppant selection is very important...

Rueda, Jose Ignacio

2012-06-07T23:59:59.000Z

319

Fracture of aluminum naval structures  

E-Print Network [OSTI]

Structural catastrophic failure of naval vessels due to extreme loads such as underwater or air explosion, high velocity impact (torpedoes), or hydrodynamic loads (high speed vessels) is primarily caused by fracture. ...

Galanis, Konstantinos, 1970-

2007-01-01T23:59:59.000Z

320

Fracture-Induced Anisotropic Attenuation  

E-Print Network [OSTI]

simplicity. The expanded fracture compliance matrix of each set is. Sf ¼ s11 s12. 0 ..... ?59?. (in MPa), where q = 2,300 kg/m3, e.g., c11 = 23 GPa . We assume a ...

2012-03-23T23:59:59.000Z

Note: This page contains sample records for the topic "outflow fracture permeability" 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

4D imaging of fracturing in organic-rich shales during heating  

SciTech Connect (OSTI)

To better understand the mechanisms of fracture pattern development and fluid escape in low permeability rocks, we performed time-resolved in situ X-ray tomography imaging to investigate the processes that occur during the slow heating (from 60 to 400 C) of organic-rich Green River shale. At about 350 C cracks nucleated in the sample, and as the temperature continued to increase, these cracks propagated parallel to shale bedding and coalesced, thus cutting across the sample. Thermogravimetry and gas chromatography revealed that the fracturing occurring at {approx}350 C was associated with significant mass loss and release of light hydrocarbons generated by the decomposition of immature organic matter. Kerogen decomposition is thought to cause an internal pressure build up sufficient to form cracks in the shale, thus providing pathways for the outgoing hydrocarbons. We show that a 2D numerical model based on this idea qualitatively reproduces the experimentally observed dynamics of crack nucleation, growth and coalescence, as well as the irregular outlines of the cracks. Our results provide a new description of fracture pattern formation in low permeability shales.

Maya Kobchenko; Hamed Panahi; François Renard; Dag K. Dysthe; Anders Malthe-Sørenssen; Adriano Mazzini; Julien Scheibert1; Bjørn Jamtveit; Paul Meakin

2011-12-01T23:59:59.000Z

322

NEW AND NOVEL FRACTURE STIMULATION TECHNOLOGIES FOR THE REVITALIZATION OF EXISTING GAS STORAGE WELLS  

SciTech Connect (OSTI)

Gas storage wells are prone to continued deliverability loss at a reported average rate of 5% per annum (in the U.S.). This is a result of formation damage due to the introduction of foreign materials during gas injection, scale deposition and/or fines mobilization during gas withdrawal, and even the formation and growth of bacteria. As a means to bypass this damage and sustain/enhance well deliverability, several new and novel fracture stimulation technologies were tested in gas storage fields across the U.S. as part of a joint U.S. Department of Energy and Gas Research Institute R&D program. These new technologies include tip-screenout fracturing, hydraulic fracturing with liquid CO{sub 2} and proppant, extreme overbalance fracturing, and high-energy gas fracturing. Each of these technologies in some way address concerns with fracturing on the part of gas storage operators, such as fracture height growth, high permeability formations, and fluid sensitivity. Given the historical operator concerns over hydraulic fracturing in gas storage wells, plus the many other unique characteristics and resulting stimulation requirements of gas storage reservoirs (which are described later), the specific objective of this project was to identify new and novel fracture stimulation technologies that directly address these concerns and requirements, and to demonstrate/test their potential application in gas storage wells in various reservoir settings across the country. To compare these new methods to current industry deliverability enhancement norms in a consistent manner, their application was evaluated on a cost per unit of added deliverability basis, using typical non-fracturing well remediation methods as the benchmark and considering both short-term and long-term deliverability enhancement results. Based on the success (or lack thereof) of the various fracture stimulation technologies investigated, guidelines for their application, design and implementation have been developed. A final research objective was to effectively deploy the knowledge and experience gained from the project to the gas storage industry at-large.

Unknown

1999-12-01T23:59:59.000Z

323

Characterization and estimation of permeability correlation structure from performance data  

SciTech Connect (OSTI)

In this study, the influence of permeability structure and correlation length on the system effective permeability and recovery factors of 2-D cross-sectional reservoir models, under waterflood, is investigated. Reservoirs with identical statistical representation of permeability attributes are shown to exhibit different system effective permeability and production characteristics which can be expressed by a mean and variance. The mean and variance are shown to be significantly influenced by the correlation length. Detailed quantification of the influence of horizontal and vertical correlation lengths for different permeability distributions is presented. The effect of capillary pressure, P{sub c1} on the production characteristics and saturation profiles at different correlation lengths is also investigated. It is observed that neglecting P{sub c} causes considerable error at large horizontal and short vertical correlation lengths. The effect of using constant as opposed to variable relative permeability attributes is also investigated at different correlation lengths. Next we studied the influence of correlation anisotropy in 2-D reservoir models. For a reservoir under five-spot waterflood pattern, it is shown that the ratios of breakthrough times and recovery factors of the wells in each direction of correlation are greatly influenced by the degree of anisotropy. In fully developed fields, performance data can aid in the recognition of reservoir anisotropy. Finally, a procedure for estimating the spatial correlation length from performance data is presented. Both the production performance data and the system`s effective permeability are required in estimating the correlation length.

Ershaghi, I.; Al-Qahtani, M. [Univ. of Southern California, Los Angeles, CA (United States)

1997-08-01T23:59:59.000Z

324

IMPACT OF CAPILLARY AND BOND NUMBERS ON RELATIVE PERMEABILITY  

SciTech Connect (OSTI)

Recovery and recovery rate of oil, gas and condensates depend crucially on their relative permeability. Relative permeability in turn depends on the pore structure, wettability and flooding conditions, which can be represented by a set of dimensionless groups including capillary and bond numbers. The effect of flooding conditions on drainage relative permeabilities is not well understood and is the overall goal of this project. This project has three specific objectives: to improve the centrifuge relative permeability method, to measure capillary and bond number effects experimentally, and to develop a pore network model for multiphase flows. A centrifuge has been built that can accommodate high pressure core holders and x-ray saturation monitoring. The centrifuge core holders can operate at a pore pressure of 6.9 MPa (1000 psi) and an overburden pressure of 17 MPa (2500 psi). The effect of capillary number on residual saturation and relative permeability in drainage flow has been measured. A pore network model has been developed to study the effect of capillary numbers and viscosity ratio on drainage relative permeability. Capillary and Reynolds number dependence of gas-condensate flow has been studied during well testing. A method has been developed to estimate relative permeability parameters from gas-condensate well test data.

Kishore K. Mohanty

2002-09-30T23:59:59.000Z

325

E-Print Network 3.0 - altered permeability states Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Collection: Geosciences 34 Direct Prediction of the Absolute Permeability of Unconsolidated and Consolidated Reservoir Rock Summary: is to calculate the absolute permeability...

326

Fracture Modeling and Flow Behavior in Shale Gas Reservoirs Using Discrete Fracture Networks  

E-Print Network [OSTI]

Fluid flow process in fractured reservoirs is controlled primarily by the connectivity of fractures. The presence of fractures in these reservoirs significantly affects the mechanism of fluid flow. They have led to problems in the reservoir which...

Ogbechie, Joachim Nwabunwanne

2012-02-14T23:59:59.000Z

327

Estimation of fracture compliance from tubewaves generated at a fracture intersecting a borehole  

E-Print Network [OSTI]

Understanding fracture compliance is important for characterizing fracture networks and for inferring fluid flow in the subsurface. In an attempt to estimate fracture compliance in the field, we developed a new model to ...

Bakku, Sudhish Kumar

2011-01-01T23:59:59.000Z

328

The determination of permeability using a pulse decay technique  

E-Print Network [OSTI]

pressures from 0 to 15, 000 psi and a maximum pore pressure of 16 psi. The core samples studied had permeabilities rang1ng from 40 to 319 md. They concluded that permeability of sandstone decreases with increase in overburden pressure. The major reduct1...on occurred over the range of 0 to 3000 psi overburden pressure. At 3000 psi overburden pressure, permeabilities ranged from 59 to 89 per cent of their orig1nal unstressed cond1tions, as illustrated in F1g. l. In 1969, Ritch and Kozik4 reported...

Rowe, William Charlton

1985-01-01T23:59:59.000Z

329

INTERPRETATION OF A HYDRAULIC FRACTURING EXPERIMENT, MONTICELLO, SOUTH CAROLINA  

E-Print Network [OSTI]

Letters INTERPRETATION OF A HYDRAULIC FRACTURING EXPERIMENT,12091 INTERPRETATION OF A HYDRAULIC FRACTURING EXPERIMENT,transient data from a hydraulic fracturing experiment have

Narasimhan, T.N.

2014-01-01T23:59:59.000Z

330

Analysis Of Macroscopic Fractures In Granite In The Hdr Geothermal...  

Open Energy Info (EERE)

between core and acoustic borehole imagery. Detailed structural analysis of the fracture population indicates that fractures are grouped in two principal fractures sets...

331

Fracture Evolution Following a Hydraulic Stimulation within an...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Fracture Evolution Following a Hydraulic Stimulation within an EGS Reservoir Fracture Evolution Following a Hydraulic Stimulation within an EGS Reservoir Fracture Evolution...

332

Aging and Fracture of Human Cortical Bone and Tooth Dentin  

E-Print Network [OSTI]

Mechanistic aspects of fracture and R-curve behavior inof failure of solid biomaterials and bone: `fracture' and `pre- fracture' toughness. Materials Science and Engineering:

Ager III, Joel W.

2008-01-01T23:59:59.000Z

333

DNAPL invasion into a partially saturated dead-end fracture  

E-Print Network [OSTI]

Mobilization in Rock Fractures, Water Resources Research,of DNAPL trapped in dead-end fractures, Geophysical Researchpartially saturated dead-end fracture and a DNAPL lens above

Su, Grace W.; Javandel, Iraj

2008-01-01T23:59:59.000Z

334

Updated fracture incidence rates for the US version of FRAX®  

E-Print Network [OSTI]

presenting with non-vertebral fractures. Osteoporos Int 18:2006) Epidemiology of vertebral fractures: implications forORIGINAL ARTICLE Updated fracture incidence rates for the US

Ettinger, B.; Black, D. M.; Dawson-Hughes, B.; Pressman, A. R.; Melton, L. J.

2010-01-01T23:59:59.000Z

335

Transphyseal Fracture of the Distal Humerus in a Neonate  

E-Print Network [OSTI]

M edicine Transphyseal Fracture of the Distal Humerus in aalignment without osseous fracture and a moderate joint2] revealed a transverse fracture through the distal left

Baker, Annalee M; Methratta, Sosamma T.; Choudhary, Arabinda K

2011-01-01T23:59:59.000Z

336

accretion-disk outflows ii: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

field direction in the stellar wind is opposite to that in the disk wind. The maximum speed of the outflow is about the Keplerian speed at the inner disk radius. With the chosen...

337

The role of impeller outflow conditions on the performance and stability of airfoil vaned radial diffusers  

E-Print Network [OSTI]

This thesis quantifies the relative importance of the impeller outflow angle, Mach number, non-uniformity and unsteadiness on diffuser performance, through diffuser experiments in a compressor stage and in a swirling flow ...

Everitt, Jonathan (Jonathan Neil)

2014-01-01T23:59:59.000Z

338

E-Print Network 3.0 - anisotropic galactic outflows Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

feedback processes in the Superwind galaxy NGC1482? Ananda Hota1 Summary: of the galactic wind outflow is very small, nearly 6 million years these long HI-tails suggest that this...

339

Uncertainty in the maximum principal stress estimated from hydraulic fracturing Measurements due to the presence of the induced fracture  

E-Print Network [OSTI]

reopening during hydraulic fracturing stress determinations.Laboratory study of hydraulic fracturing pressure data?Howevaluation of hydraulic fracturing stress measurement

Rutqvist, Jonny; Tsang, Chin-fu; Stephansson, Ove

2000-01-01T23:59:59.000Z

340

Relativistic outflow from two thermonuclear shell flashes on neutron stars  

E-Print Network [OSTI]

We study the exceptionally short (32-41 ms) precursors of two intermediate-duration thermonuclear X-ray bursts observed with RXTE from the neutron stars in 4U 0614+09 and 2S 0918-549. They exhibit photon fluxes that surpass those at the Eddington limit later in the burst by factors of 2.6 to 3.1. We are able to explain both the short duration and the super-Eddington flux by mildly relativistic outflow velocities of 0.1$c$ to 0.3$c$ subsequent to the thermonuclear shell flashes on the neutron stars. These are the highest velocities ever measured from any thermonuclear flash. The precursor rise times are also exceptionally short: about 1 ms. This is inconsistent with predictions for nuclear flames spreading laterally as deflagrations and suggests detonations instead. This is the first time that a detonation is suggested for such a shallow ignition column depth ($y_{\\rm ign}$ = 10$^{10}$ g cm$^{-2}$). The detonation would possibly require a faster nuclear reaction chain, such as bypassing the alpha-capture on $^...

Zand, Jean in 't; Cavecchi, Yuri

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "outflow fracture permeability" 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

Combined permeable pavement and ground source heat pump systems   

E-Print Network [OSTI]

The PhD thesis focuses on the performance assessment of permeable pavement systems incorporating ground source heat pumps (GSHP). The relatively high variability of temperature in these systems allows for the survival of pathogenic organisms within...

Grabowiecki, Piotr

2010-01-01T23:59:59.000Z

342

IMPROVING MIX DESIGN AND CONSTRUCTION OF PERMEABLE FRICTION COURSE MIXTURES  

E-Print Network [OSTI]

Permeable friction course (PFC), or new generation open-graded friction course (OGFC) mixtures, are hot mix asphalt (HMA) characterized by high total air voids (AV) content (minimum 18 %) as compared to the most commonly used dense-graded HMA...

Alvarez Lugo, Allex Eduardo

2012-02-14T23:59:59.000Z

343

Hydrogen permeable protective coating for a catalytic surface  

DOE Patents [OSTI]

A protective coating for a surface comprising a layer permeable to hydrogen, said coating being deposited on a catalyst layer; wherein the catalytic activity of the catalyst layer is preserved.

Liu, Ping (Irvine, CA); Tracy, C. Edwin (Golen, CO); Pitts, J. Roland (Lakewood, CO); Lee, Se-Hee (Lakewood, CO)

2007-06-19T23:59:59.000Z

344

Stress-dependent permeability on tight gas reservoirs  

E-Print Network [OSTI]

test analysis of tight gas reservoirs. Estimation of these parameters depends on draw down in the reservoir. The great impact of permeability, skin factor and OGIP calculations are useful in business decisions and profitability for the oil company...

Rodriguez, Cesar Alexander

2005-02-17T23:59:59.000Z

345

Experimental Study on Rock Deformation and Permeability Variation  

E-Print Network [OSTI]

The development of a petroleum reservoir would inevitably induce a rearrangement of the in-situ stress field. The rearrangement of the stress field would then bring about a deformation of the reservoir rock and a change of the permeability...

Ding, Jihui

2013-08-01T23:59:59.000Z

346

Permeability, Resistivity and Strength of Fouled Railroad Ballast  

E-Print Network [OSTI]

particles between the ballast particles; therefore, permeability and resistivity were also correlated. The strength properties of clean and fouled ballast were also evaluated using large direct shear box and modified direct shear box (extension in height...

Rahman, A. J.

2013-08-31T23:59:59.000Z

347

A Simple Model for Estimating Water Balance and Salinity of Reservoirs and Outflow  

E-Print Network [OSTI]

on flow and salinity of the stream and the floodplains. The first part deals with water and salt balance in reservoirs. The primary purpose of the model is to predict outflow salinity from the reservoir storage and inflow information in advance... management strategy, yet the method to predict outflow salinity has not been adequately examined. The study reported here examined the water and salt balance in a reservoir using a two-layer model. This model assumes that inflow blends with the storage...

Miyamoto, S; Yuan, F; Anand, Shilpa

2010-08-23T23:59:59.000Z

348

Water permeability and microstructure of three old concretes  

SciTech Connect (OSTI)

Measurement of the permeability of concrete to water is complicated by the self-sealing phenomenon, the progressive reduction of flow during the test. Many researchers have attributed self sealing to the hydration of previously unreacted cement on exposure to water. This paper describes permeability tests on concretes continuously hydrated for 26 years. Backscattered electron images show that virtually no unhydrated cement remains in these specimens, yet they exhibit self-sealing behavior.

Hearn, N.; Detwiler, R.J.; Sframeli, C. (Univ. of Toronto, Ontario (Canada). Dept. of Civil Engineering)

1994-01-01T23:59:59.000Z

349

Determining coal permeabilities through constant pressure production interference testing  

E-Print Network [OSTI]

DETERMINING COAL PERMEABILITIES THROUGH CONSTANT PRESSURE PRODUCTION INTERFERENCE TESTING A Thesis by STEPHEN KURT SCHUBARTH Submitted to the Graduate College of Texas ASM University fn Partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE December 1983 Major Subject: Petroleum Engineering DETERMINING COAL PERMEABILITIES THROUGH CONSTANT PRESSURE PRODUCTION INTERFERENCE TESTING A Thesis by STEPHEN KURT SCHUBARTH Approved as to style and content by: tephen A. Hold...

Schubarth, Stephen Kurt

2012-06-07T23:59:59.000Z

350

The effect of temperature on relative permeability of unconsolidated sand  

E-Print Network [OSTI]

THE EFFECT OF TEMPERATURE ON RELATIVE PERMEABILITY OF UNCONSOLIDATED SAND A Thesis By SIMON YSRAEL Submitted to the Graduate College of the Texas A%M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE.... Summary of Water Flood at 150 F VII. Summary of Water Flood at 293 F 48 49 50 ABSTRACT The purpose of this work was to investigate the effect of temperature on relative permeability of unconsolidated sand. The present work was performed...

Ysrael, Simon

2012-06-07T23:59:59.000Z

351

Investigation of the rate sensitivity of pseudo relative permeabilities  

E-Print Network [OSTI]

of hypothetical reservoir stratifications were considered. Cross-sectional simulation runs were made using each stratification case for a range of waterflood injection rates and endpoint mobility ratios. Dynamic pseudo relative permeabilities were calculated... , These dynamic pseudo relative permeabilities were developed for those reservoirs that do not satisfy the assumptions of the vertical equilibrium or viscous-dominated pKr models. For waterflooding a stratified oil reservoir, fluid flow rate (velocity...

Brittain, Charles Finney

1986-01-01T23:59:59.000Z

352

Permeability decrease in argillaceous sandstone; experiments and modelling  

SciTech Connect (OSTI)

Core flooding experiments on argillaceous sandstone are carried out showing that for high injection flow rates permeability reduction occurs. The decrease of permeability is a consequence of the migration of insitu particles. Two models are used to simulate the observed phenomena. The so-called network model is able to give insight in the physics behind the particle migration. The other model based on mass balance and constitutive laws is used for quantitative and qualitative comparison with the experiments.

Egberts, Paul; van Soest, Lennard; Vernoux, Jean-Francois

1996-01-24T23:59:59.000Z

353

Monitoring hydraulic fracture growth: Laboratory experiments  

SciTech Connect (OSTI)

The authors carry out small-scale hydraulic fracture experiments to investigate the physics of hydraulic fracturing. The laboratory experiments are combined with time-lapse ultrasonic measurements with active sources using both compressional and shear-wave transducers. For the time-lapse measurements they focus on ultrasonic measurement changes during fracture growth. As a consequence they can detect the hydraulic fracture and characterize its shape and geometry during growth. Hence, this paper deals with fracture characterization using time-lapse acoustic data. Hydraulic fracturing is used in the oil and gas industry to stimulate reservoir production.

Groenenboom, J.; Dam, D.B. van

2000-04-01T23:59:59.000Z

354

Fracturing pressures and near-well fracture geometry of arbitrarily oriented and horizontal wells  

SciTech Connect (OSTI)

The hydraulic fracturing of arbitrarily oriented and horizontal wells is made challenging by the far more complicated near-well fracture geometry compared to that of conventional vertical wells. This geometry is important both for hydraulic fracture propagation and the subsequent post-treatment well performance. Fracture tortuosity of arbitrarily oriented and horizontal wells is likely to cause large initiation pressures and reduction in the fracture widths. This paper presents a comprehensive study of the effects of important variables, including the principal stresses, wellbore orientation, and perforation configuration on fracture geometry. Initiation pressures, the contact between arbitrarily oriented wells and the fracture plane, and the near-well fracture geometry are determined and discussed. This study also shows that because of the near-well stress concentration the fracture width at the wellbore is always smaller than the maximum fracture width. This can have important consequences during hydraulic fracturing.

Chen, Z.; Economides, M.J.

1995-12-31T23:59:59.000Z

355

Theory of Bipolar Outflows from High-Mass Young Stellar Objects  

E-Print Network [OSTI]

There is a growing number of observational indicators for the presence of bipolar outflows in massive, young stellar objects that are still accreting mass as part of their formation process. In particular, there is evidence that the outflows from these objects can attain higher velocities and kinetic luminosities than their lower-mass counterparts. Furthermore, the higher-mass objects appear to smoothly continue the correlation found in T Tauri stars between outflow and accretion signatures, and in several cases there are direct clues to the existence of a circumstellar disk from optical and infrared imaging and spectroscopy as well as from millimeter-wavelength interferometry. These results suggest that the disk-outflow connection found in low-mass pre-main-sequence stars extends to more massive objects, and that a similar physical mechanism may drive the outflows in both cases. I examine the observational basis for this hypothesis and consider how the commonly invoked centrifugally driven wind models of bipolar outflows in low-mass stars would be affected by the various physical processes (such as photoionization, photoevaporation, radiation pressure, and stellar wind ram pressure) that operate in higher-mass stars. I then list some of the interesting questions that one could hope to address as this young field of research continues to develop.

Arieh Konigl

1999-03-11T23:59:59.000Z

356

MAGNETIC RECONNECTION ALONG QUASI-SEPARATRIX LAYERS AS A DRIVER OF UBIQUITOUS ACTIVE REGION OUTFLOWS  

SciTech Connect (OSTI)

Hinode's EUV Imaging Spectrometer (EIS) has discovered ubiquitous outflows of a few to 50 km s{sup -1} from active regions (ARs). These outflows are most prominent at the AR boundary and appear over monopolar magnetic areas. They are linked to strong non-thermal line broadening and are stronger in hotter EUV lines. The outflows persist for at least several days. Using Hinode EIS and X-Ray Telescope observations of AR 10942 coupled with magnetic modeling, we demonstrate that the outflows originate from specific locations of the magnetic topology where field lines display strong gradients of magnetic connectivity, namely quasi-separatrix layers (QSLs), or in the limit of infinitely thin QSLs, separatrices. We found the strongest AR outflows to be in the vicinity of QSL sections located over areas of strong magnetic field. We argue that magnetic reconnection at QSLs separating closed field lines of the AR and either large-scale externally connected or 'open' field lines is a viable mechanism for driving AR outflows which are likely sources of the slow solar wind.

Baker, D.; Van Driel-Gesztelyi, L.; Murray, M. J. [University College London, Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom); Mandrini, C. H. [Instituto de AstronomIa y fisica del Espacio, CONICET-UBA, CC. 67, Suc. 28, 1428 Buenos Aires (Argentina); Demoulin, P. [Observatoire de Paris, LESIA, UMR 8109 (CNRS), Meudon-Principal Cedex (France)

2009-11-01T23:59:59.000Z

357

Fracture characterization and estimation of fracture porosity of naturally fractured reservoirs with no matrix porosity using stochastic fractal models  

E-Print Network [OSTI]

Determining fracture characteristics at the laboratory scale is a major challenge. It is known that fracture characteristics are scale dependent; as such, the minimum sample size should be deduced in order to scale to reservoir dimensions. The main...

Kim, Tae Hyung

2009-05-15T23:59:59.000Z

358

The use of tracers to analyze the effects of reinjection into fractured geothermal reservoirs  

SciTech Connect (OSTI)

This paper discusses the use of tracers as a reservoir engineering tool in fractured geothermal reservoirs. The principle concern in injecting cooler spent fluids into a fractured reservoir is that the fluids may move through high permeability channels and return to the production wells after contacting a relatively small volume of rock. As a consequence of this rapid transport, the fluids will be only partially reheated and after a short period time will effectively mine the heat from the limited volume of rock. The production wells will then experience a rapid and premature reduction in thermal output. Tracers can be used to infer the existence of high mobility conduits between injection and production wells and to monitor chemical changes of an injected fluid. Since tracer arrival precedes thermal breakthrough, tracer tests are a very useful forecasting tool.

Horne, R.N.; Johns, R.A.; Adams, M.C.; Moore, J.N.; Stiger, S.G.

1987-01-01T23:59:59.000Z

359

VALIDATION OF MASSIVELY PARALLEL SIMULATIONS OF DYNAMIC FRACTURE AND  

E-Print Network [OSTI]

VALIDATION OF MASSIVELY PARALLEL SIMULATIONS OF DYNAMIC FRACTURE AND FRAGMENTATION OF BRITTLE element simulations of dynamic fracture and fragmentation of brittle solids are presented. Fracture the results of massively parallel numerical simulations of dynamic fracture and fragmentation in brittle

Barr, Al

360

Tritium Transport at the Rulison Site, a Nuclear-stimulated Low-permeability Natural Gas Reservoir  

SciTech Connect (OSTI)

The U.S. Department of Energy (DOE) and its predecessor agencies conducted a program in the 1960s and 1970s that evaluated technology for the nuclear stimulation of low-permeability natural gas reservoirs. The second project in the program, Project Rulison, was located in west-central Colorado. A 40-kiltoton nuclear device was detonated 2,568 m below the land surface in the Williams Fork Formation on September 10, 1969. The natural gas reservoirs in the Williams Fork Formation occur in low permeability, fractured sandstone lenses interbedded with shale. Radionuclides derived from residual fuel products, nuclear reactions, and activation products were generated as a result of the detonation. Most of the radionuclides are contained in a cooled, solidified melt glass phase created from vaporized and melted rock that re-condensed after the test. Of the mobile gas-phase radionuclides released, tritium ({sup 3}H or T) migration is of most concern. The other gas-phase radionuclides ({sup 85}Kr, {sup 14}C) were largely removed during production testing in 1969 and 1970 and are no longer present in appreciable amounts. Substantial tritium remained because it is part of the water molecule, which is present in both the gas and liquid (aqueous) phases. The objectives of this work are to calculate the nature and extent of tritium contamination in the subsurface from the Rulison test from the time of the test to present day (2007), and to evaluate tritium migration under natural-gas production conditions to a hypothetical gas production well in the most vulnerable location outside the DOE drilling restriction. The natural-gas production scenario involves a hypothetical production well located 258 m horizontally away from the detonation point, outside the edge of the current drilling exclusion area. The production interval in the hypothetical well is at the same elevation as the nuclear chimney created by the detonation, in order to evaluate the location most vulnerable to tritium migration.

C. Cooper; M. Ye; J. Chapman

2008-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "outflow fracture permeability" 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

Development of RWHet to Simulate Contaminant Transport in Fractured Porous Media  

SciTech Connect (OSTI)

Accurate simulation of matrix diffusion in regional-scale dual-porosity and dual-permeability media is a critical issue for the DOE Underground Test Area (UGTA) program, given the prevalence of fractured geologic media on the Nevada National Security Site (NNSS). Contaminant transport through regional-scale fractured media is typically quantified by particle-tracking based Lagrangian solvers through the inclusion of dual-domain mass transfer algorithms that probabilistically determine particle transfer between fractures and unfractured matrix blocks. UGTA applications include a wide variety of fracture aperture and spacing, effective diffusion coefficients ranging four orders of magnitude, and extreme end member retardation values. This report incorporates the current dual-domain mass transfer algorithms into the well-known particle tracking code RWHet [LaBolle, 2006], and then tests and evaluates the updated code. We also develop and test a direct numerical simulation (DNS) approach to replace the classical transfer probability method in characterizing particle dynamics across the fracture/matrix interface. The final goal of this work is to implement the algorithm identified as most efficient and effective into RWHet, so that an accurate and computationally efficient software suite can be built for dual-porosity/dual-permeability applications. RWHet is a mature Lagrangian transport simulator with a substantial user-base that has undergone significant development and model validation. In this report, we also substantially tested the capability of RWHet in simulating passive and reactive tracer transport through regional-scale, heterogeneous media. Four dual-domain mass transfer methodologies were considered in this work. We first developed the empirical transfer probability approach proposed by Liu et al. [2000], and coded it into RWHet. The particle transfer probability from one continuum to the other is proportional to the ratio of the mass entering the other continuum to the mass in the current continuum. Numerical examples show that this method is limited to certain ranges of parameters, due to an intrinsic assumption of an equilibrium concentration profile in the matrix blocks in building the transfer probability. Subsequently, this method fails in describing mass transfer for parameter combinations that violate this assumption, including small diffusion coefficients (i.e., the free-water molecular diffusion coefficient 1×10-11 meter2/second), relatively large fracture spacings (such as meter), and/or relatively large matrix retardation coefficients (i.e., ). These “outliers” in parameter range are common in UGTA applications. To address the above limitations, we then developed a Direct Numerical Simulation (DNS)-Reflective method. The novel DNS-Reflective method can directly track the particle dynamics across the fracture/matrix interface using a random walk, without any empirical assumptions. This advantage should make the DNS-Reflective method feasible for a wide range of parameters. Numerical tests of the DNS-Reflective, however, show that the method is computationally very demanding, since the time step must be very small to resolve particle transfer between fractures and matrix blocks. To improve the computational efficiency of the DNS approach, we then adopted Roubinet et al.’s method [2009], which uses first passage time distributions to simulate dual-domain mass transfer. The DNS-Roubinet method was found to be computationally more efficient than the DNS-Reflective method. It matches the analytical solution for the whole range of major parameters (including diffusion coefficient and fracture aperture values that are considered “outliers” for Liu et al.’s transfer probability method [2000]) for a single fracture system. The DNS-Roubinet method, however, has its own disadvantage: for a parallel fracture system, the truncation of the first passage time distribution creates apparent errors when the fracture spacing is small, and thus it tends to erroneously predict breakthrough curves (BTCs) for th

Zhang, Yong; LaBolle, Eric; Reeves, Donald M; Russell, Charles

2012-07-01T23:59:59.000Z

362

Nonplanar fracture propagation from a horizontal wellbore: Experimental study  

SciTech Connect (OSTI)

This paper presents experimental results related to hydraulic fracturing of a horizontal well, specifically the nonplanar fracture geometries resulting from fracture initiation and propagation. Experiments were designed to investigate nonplanar fracture geometries. This paper discusses how these nonplanar fractures can be responsible for premature screenout and excessive treatment pressure when a horizontal well is hydraulically fractured. Reasons for unsuccessful hydraulic fracturing treatments of a horizontal well are presented and recommendations to ensure clear communication channels between the wellbore and the fracture are given.

Abass, H.H.; Hedayati, S.; Meadows, D.L.

1996-08-01T23:59:59.000Z

363

Harmonic experiments to model fracture induced anisotropy KAUST ...  

E-Print Network [OSTI]

May 9, 2012 ... hydrocarbon and geothermal reservoirs are mainly composed of fractured rocks. Harmonic experiments to model fracture induced anisotropy ...

santos,,,

364

Tracer Methods for Characterizing Fracture Stimulation in Engineered...  

Broader source: Energy.gov (indexed) [DOE]

Tracer Methods for Characterizing Fracture Stimulation in Engineered Geothermal Systems (EGS) Tracer Methods for Characterizing Fracture Stimulation in Engineered Geothermal...

365

Three Models for Water ooding in a Naturally Fractured Petroleum ...  

E-Print Network [OSTI]

THREE MODELS FOR WATERFLOODING IN A NATURALLY. FRACTURED ... 1. Introduction. For the purposes of this paper a naturally fractured reservoir.

366

Modeling Wettability Alteration using Chemical EOR Processes in Naturally Fractured Reservoirs  

SciTech Connect (OSTI)

The objective of our search is to develop a mechanistic simulation tool by adapting UTCHEM to model the wettability alteration in both conventional and naturally fractured reservoirs. This will be a unique simulator that can model surfactant floods in naturally fractured reservoir with coupling of wettability effects on relative permeabilities, capillary pressure, and capillary desaturation curves. The capability of wettability alteration will help us and others to better understand and predict the oil recovery mechanisms as a function of wettability in naturally fractured reservoirs. The lack of a reliable simulator for wettability alteration means that either the concept that has already been proven to be effective in the laboratory scale may never be applied commercially to increase oil production or the process must be tested in the field by trial and error and at large expense in time and money. The objective of Task 1 is to perform a literature survey to compile published data on relative permeability, capillary pressure, dispersion, interfacial tension, and capillary desaturation curve as a function of wettability to aid in the development of petrophysical property models as a function of wettability. The new models and correlations will be tested against published data. The models will then be implemented in the compositional chemical flooding reservoir simulator, UTCHEM. The objective of Task 2 is to understand the mechanisms and develop a correlation for the degree of wettability alteration based on published data. The objective of Task 3 is to validate the models and implementation against published data and to perform 3-D field-scale simulations to evaluate the impact of uncertainties in the fracture and matrix properties on surfactant alkaline and hot water floods.

Mojdeh Delshad; Gary A. Pope; Kamy Sepehrnoori

2007-09-30T23:59:59.000Z

367

Modeling of Acid Fracturing in Carbonate Reservoirs  

E-Print Network [OSTI]

The acid fracturing process is a thermal, hydraulic, mechanical, and geochemical (THMG)-coupled phenomena in which the behavior of these variables are interrelated. To model the flow behavior of an acid into a fracture, mass and momentum balance...

Al Jawad, Murtada s

2014-06-05T23:59:59.000Z

368

Self-potential observations during hydraulic fracturing  

E-Print Network [OSTI]

during hydraulic fracturing Moore and Glaser, in press JGR,press JGR, B – 2006JB004373 where m is the average hydraulichydraulic fracturing with water. Moore and Glaser, in press

Moore, Jeffrey R.; Glaser, Steven D.

2008-01-01T23:59:59.000Z

369

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

370

Fluid Flow Simulation in Fractured Reservoirs  

E-Print Network [OSTI]

The purpose of this study is to analyze fluid flow in fractured reservoirs. In most petroleum reservoirs, particularly carbonate reservoirs and some tight sands, natural fractures play a critical role in controlling fluid ...

Sarkar, Sudipta

2002-01-01T23:59:59.000Z

371

Surrogate-based optimization of hydraulic fracturing in pre-existing fracture networks  

E-Print Network [OSTI]

Surrogate-based optimization of hydraulic fracturing in pre-existing fracture networks Mingjie Chen Keywords: Hydraulic fracturing Fractal dimension Surrogate model Optimization Global sensitivity a b s t r a c t Hydraulic fracturing has been used widely to stimulate production of oil, natural gas

Lu, Zhiming

372

A model of fracture nucleation, growth and arrest, and consequences for fracture density and scaling  

E-Print Network [OSTI]

A model of fracture nucleation, growth and arrest, and consequences for fracture density; accepted 1 February 2013; published 25 April 2013. [1] In order to improve discrete fracture network (DFN a new DFN modeling based on the evolution of fracture network formation--nucleation, growth, and arrest

Boyer, Edmond

373

FEM Analysis ofFEM Analysis of Deformation and Fracture ofDeformation and Fracture of  

E-Print Network [OSTI]

FEM Analysis ofFEM Analysis of Deformation and Fracture ofDeformation and Fracture of Deformation and Fracture in Polycrystalline -TiAl + 2-Ti3Al Single Crystals #12;Use of -TiAl + 2-Ti3Al Alloys-Temperature Ductility ·Low Ambient-Temperature Fracture Toughness (KIC

Grujicic, Mica

374

Statistical fracture modeling: crack path and fracture criteria with application to homogeneous and  

E-Print Network [OSTI]

Statistical fracture modeling: crack path and fracture criteria with application to homogeneous; accepted 23 January 2002 Abstract Analysis has been performed on fracture initiation near a crack in a brittle material with strength described by Weibull statistics. This nonlocal fracture model allows

Ritchie, Robert

375

A Membrane Deflection Fracture Experiment to Investigate Fracture Toughness of Freestanding MEMS Materials  

E-Print Network [OSTI]

A Membrane Deflection Fracture Experiment to Investigate Fracture Toughness of Freestanding MEMS Materials H.D. Espinosa* and B. Peng ABSTRACT This paper presents a novel Membrane Deflection Fracture Experiment (MDFE) to investigate the fracture toughness of MEMS and other advanced materials in thin film

Espinosa, Horacio D.

376

Discrete fracture modeling for fractured reservoirs using Voronoi grid blocks  

E-Print Network [OSTI]

or pseudofracture groups modeled in their own grid blocks. Discrete Fracture Modeling (DFN) is still a relatively new field, and most research on it up to this point has been done with Delaunay tessellations. This research investigates an alternative approach using...

Gross, Matthew Edward

2007-09-17T23:59:59.000Z

377

Wave Propagation in Fractured Poroelastic Media  

E-Print Network [OSTI]

Seismic wave propagation through fractures and cracks is an important subject in exploration and production geophysics, earthquake seismology and mining.

378

CT measurements of two-phase flow in fractured porous media  

SciTech Connect (OSTI)

The simulation of flow in naturally fractured reservoirs commonly divides the reservoir into two continua - the matrix system and the fracture system. Flow equations are written presuming that the primary flow between grid blocks occurs through the fracture system and that the primary fluid storage is in the matrix system. The dual porosity formulation of the equations assumes that there is no flow between matrix blocks while the dual permeability formulation allows fluid movement between matrix blocks. Since most of the fluid storage is contained in the matrix, recovery is dominated by the transfer of fluid from the matrix to the high conductivity fractures. The physical mechanisms influencing this transfer have been evaluated primarily through numerical studies. Relatively few experimental studies have investigated the transfer mechanisms. Early studies focused on the prediction of reservoir recoveries from the results of scaled experiments on single reservoir blocks. Recent experiments have investigated some of the mechanisms that are dominant in gravity drainage situations and in small block imbibition displacements. The mechanisms active in multiphase flow in fractured media need to be further illuminated, since some of the experimental results appear to be contradictory. This report describes the design, construction, and preliminary results of an experiment that studies imbibition displacement in two fracture blocks. Multiphase (oil/water) displacements will be conducted at the same rate on three core configurations. The configurations are a compact core, a two-block system with a 1 mm spacer between the blocks, and a two-block system with no spacer. The blocks are sealed in epoxy so that saturation measurements can be made throughout the displacement experiments using a Computed Tomography (CT) scanner.

Hughes, R.G.; Brigham, W.E.; Castanier, L.M.

1997-06-01T23:59:59.000Z

379

Optimizing fracture stimulation using treatment-well tiltmeters and integrated fracture modeling  

SciTech Connect (OSTI)

This paper covers the optimization of hydraulic fracture treatments in a new coalbed methane (CBM) reservoir in Wyoming. A multiwell pilot project was conducted in the Copper Ridge (CR) field to assess future development potential. Hydraulic fracture mapping was successfully performed with treatment-well tiltmeters on six wells including the first-ever used on propped treatments. The mapped fracture height was then used to calibrate the fracture model, perform on-site fracture-design changes, and optimize future fracture treatments. This paper shows how early use of fracture diagnostics can assist in the development of a new reservoir.

Mayerhofer, M.; Stutz, L.; Davis, E.; Wolhart, S. [Pinnacle Technology Houston, Houston, TX (United States)

2006-05-15T23:59:59.000Z

380

Acoustic-emission monitoring during hydraulic fracturing  

SciTech Connect (OSTI)

This paper reports that microseismic events or acoustic emissions associated with hydraulic fracturing are recorded with a borehole seismic tool in a deviated well during multirate injection, shut-in, and flowback. The event locations indicate that fracture orientation, length, and height are compatible with regional stress directions and estimates of the fracture size that are based on pressure decline.

Stewart, L. (Schlumberger-Doll Research (US)); Cassell, B.R. (Schlumberger Wireline Services (US)); Bol, G.M. (Nederlanse Aardolie Mij. B.V. (NL))

1992-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "outflow fracture permeability" 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

Hydraulic Fracturing in Michigan Integrated Assessment  

E-Print Network [OSTI]

Hydraulic Fracturing in Michigan Integrated Assessment #12;Agenda · Welcome and introduction and timeline · Panel presentation and discussion · Facilitated Q & A · Closing remarks #12;Hydraulic Fracturing · Leverages resources IA BENEFITS Benefits of Integrated Assessment #12;Key Points: · Hydraulic Fracturing (HF

Kamat, Vineet R.

382

Regulation of Hydraulic Fracturing in California  

E-Print Network [OSTI]

APRIL 2013 Regulation of Hydraulic Fracturing in California: A WAsteWAteR And WAteR QuAlity Pe | Regulation of Hydraulic Fracturing in California Wheeler Institute for Water Law & Policy Center for Law #12;Regulation of Hydraulic Fracturing in California | 3Berkeley law | wheeler InstItute for water law

Kammen, Daniel M.

383

Fractured shale reservoirs: Towards a realistic model  

SciTech Connect (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

384

Challenges in Continuum Modelling of Intergranular Fracture  

E-Print Network [OSTI]

Challenges in Continuum Modelling of Intergranular Fracture V. R. Coffman*, J. P. Sethna , A. R-2501, USA Cornell Fracture Group, Rhodes Hall, Cornell University, Ithaca, NY 14853-2501, USA § Department fracture in polycrystals is often simulated by finite elements coupled to a cohesive zone model

Sethna, James P.

385

FRACTURE IN DISORDERED BRITTLE MEDIA A Dissertation  

E-Print Network [OSTI]

FRACTURE IN DISORDERED BRITTLE MEDIA A Dissertation Presented to the Faculty of the Graduate School by Ashivni Shekhawat May 2013 #12;c 2013 Ashivni Shekhawat ALL RIGHTS RESERVED #12;FRACTURE IN DISORDERED- lem of brittle fracture in disordered media. Chapters 2 and 4 are concerned with various aspects

Sethna, James P.

386

FRACTURE TOUGHNESS OF WOOD AND WOOD COMPOSITES  

E-Print Network [OSTI]

FRACTURE TOUGHNESS OF WOOD AND WOOD COMPOSITES DURING CRACK PROPAGATION Noah Matsumoto Structural, USA * Corresponding author: John.Nairn@oregonstate.edu SWST member #12;Fracture Toughness of Wood and Wood Composites During Crack Propagation ABSTRACT The mode I fracture toughness as a function of crack

Nairn, John A.

387

Models for MetaVCeramic Interface Fracture  

E-Print Network [OSTI]

ChaDter 12 Models for MetaVCeramic Interface Fracture ZHIGANG SUO C. FONG SHIH Metal shortcomingthat haslimited their wide- spread use-their tendency to fracture easily. In many systems, the low on interface fracture are reviewed in this chapter. With few exceptions, attention is limited to continuum

Suo, Zhigang

388

Interferometric hydrofracture microseism localization using neighboring fracture  

E-Print Network [OSTI]

Interferometric hydrofracture microseism localization using neighboring fracture Oleg V. Poliannikov1 , Alison E. Malcolm1 , Hugues Djikpesse2 , and Michael Prange2 ABSTRACT Hydraulic fracturing is the process of injecting high-pressure fluids into a reservoir to induce fractures and thus improve reservoir

Malcolm, Alison

389

Hydraulic Fracture: multiscale processes and moving  

E-Print Network [OSTI]

Hydraulic Fracture: multiscale processes and moving interfaces Anthony Peirce Department Mitchell (UBC) · Ed Siebrits (SLB, Houston) #12;2 Outline · What is a hydraulic fracture? · Scaling Fluid Proppant #12;6 An actual hydraulic fracture #12;7 HF experiment (Jeffrey et al CSIRO) #12;8 1D

Peirce, Anthony

390

Hydraulic Fracture: multiscale processes and moving  

E-Print Network [OSTI]

Hydraulic Fracture: multiscale processes and moving interfaces Anthony Peirce Department Siebrits (SLB, Houston) #12;2 Outline · What is a hydraulic fracture? · Mathematical models of hydraulic fracture · Scaling and special solutions for 1-2D models · Numerical modeling for 2-3D problems

Peirce, Anthony

391

Introduction That fracture is governed by processes  

E-Print Network [OSTI]

Introduction That fracture is governed by processes occurring over a wide range of length scales has been recognized since the earli- est developments of modern fracture me- chanics. Griffith's study by several decades the first at- tempts to apply atomistically grounded traction-separation laws to fracture

Beltz, Glenn E.

392

LA-13194-MS Fracture Characterization of the  

E-Print Network [OSTI]

LA-13194-MS Fracture Characterization of the Bandelier Tuff in OU-1098 (TA-2 and TA-41) LosN A T I technical correctness. #12;Fracture Characterization of the Bandelier Tuff in OU-1098 (TA-2 and TA-41 Los Alamos, New Mexico 87545 #12;1 Fracture Characterization of the Bandelier Tuff in OU-1098 (TA-2

393

Self-potential observations during hydraulic fracturing  

E-Print Network [OSTI]

1968), Permeability of granite under high pressure, J.resistivity during creep in granite, Pure Appl. Geophys. ,properties of westerly granite with applications, J.

Moore, Jeffrey R.; Glaser, Steven D.

2008-01-01T23:59:59.000Z

394

A SYSTEMATIC SEARCH FOR MOLECULAR OUTFLOWS TOWARD CANDIDATE LOW-LUMINOSITY PROTOSTARS AND VERY LOW LUMINOSITY OBJECTS  

SciTech Connect (OSTI)

We present a systematic single-dish search for molecular outflows toward a sample of nine candidate low-luminosity protostars and 30 candidate very low luminosity objects (VeLLOs; L{sub int} {<=} 0.1 L{sub Sun }). The sources are identified using data from the Spitzer Space Telescope cataloged by Dunham et al. toward nearby (D < 400 pc) star-forming regions. Each object was observed in {sup 12}CO and {sup 13}CO J = 2 {yields} 1 simultaneously using the sideband separating ALMA Band-6 prototype receiver on the Heinrich Hertz Telescope at 30'' resolution. Using five-point grid maps, we identify five new potential outflow candidates and make on-the-fly maps of the regions surrounding sources in the dense cores B59, L1148, L1228, and L1165. Of these new outflow candidates, only the map of B59 shows a candidate blue outflow lobe associated with a source in our survey. We also present larger and more sensitive maps of the previously detected L673-7 and the L1251-A-IRS4 outflows and analyze their properties in comparison to other outflows from VeLLOs. The accretion luminosities derived from the outflow properties of the VeLLOs with detected CO outflows are higher than the observed internal luminosity of the protostars, indicating that these sources likely had higher accretion rates in the past. The known L1251-A-IRS3 outflow is detected but not re-mapped. We do not detect clear, unconfused signatures of red and blue molecular wings toward the other 31 sources in the survey indicating that large-scale, distinct outflows are rare toward this sample of candidate protostars. Several potential outflows are confused with the kinematic structure in the surrounding core and cloud. Interferometric imaging is needed to disentangle large-scale molecular cloud kinematics from these potentially weak protostellar outflows.

Schwarz, Kamber R.; Shirley, Yancy L. [Steward Observatory, 933 N. Cherry Ave., Tucson, AZ 85721 (United States); Dunham, Michael M. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States)

2012-10-01T23:59:59.000Z

395

Capillary fracture of soft gels  

E-Print Network [OSTI]

A liquid droplet resting on a soft gel substrate can deform that substrate to the point of material failure, whereby fractures develop on the gel surface that propagate outwards from the contact-line in a starburst pattern. In this paper, we characterize i) the initiation process in which the number of arms in the starburst is controlled by the ratio of surface tension contrast to the gel's elastic modulus and ii) the propagation dynamics showing that once fractures are initiated they propagate with a universal power law $L\\propto t^{3/4}$. We develop a model for crack initiation by treating the gel as a linear elastic solid and computing the deformations within the substrate from the liquid/solid wetting forces. The elastic solution shows that both the location and magnitude of the wetting forces are critical in providing a quantitative prediction for the number of fractures and, hence, an interpretation of the initiation of capillary fractures. This solution also reveals that the depth of the gel is an impo...

Bostwick, Joshua B

2013-01-01T23:59:59.000Z

396

Geomechanical Simulation of Fluid-Driven Fractures  

SciTech Connect (OSTI)

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

397

CONSTRAINT EFFECT IN FRACTURE WHAT IS IT  

SciTech Connect (OSTI)

The meaning of the phrase 'constraint effect in fracture' has changed in the past two decades from 'contained plasticity' to a broader description of 'dependence of fracture toughness value on geometry of test specimen or structure'. This paper will first elucidate the fundamental mechanics reasons for the apparent 'constraint effects in fracture', followed by outlining a straightforward approach to overcoming this problem in both brittle (elastic) and ductile (elastic-plastic) fracture. It is concluded by discussing the major difference in constraint effect on fracture event in elastic and elastic-plastic materials.

Lam, P; Prof. Yuh J. Chao, P

2008-10-29T23:59:59.000Z

398

Multi-wavelength spectroscopy of the bipolar outflow from Cepheus E  

E-Print Network [OSTI]

Cepheus E is the site of an exceptional example of a protostellar outflow with a very young dynamical age and extremely high near infrared luminosity. We combine molecular spectroscopic data from the submillimeter to the near infrared in order to interpret the rotational excitation of CO and the ro-vibrational excitation of H2. We conclude that C-type shocks with a paraboloidal bow shock geometry can simultaneously explain all the molecular excitations. Extinction accounts for the deviation of the column densities from local thermodynamic equilibrium. A difference in the extinction between the red and blue-shifted outflow lobes may account for the measured flux difference. The outflow is deeply embedded in a clump of density 10^5cm^-3, yet a good fraction of atomic hydrogen, about 40%, is required to explain the excitation and statistical equilibrium. We propose that this atomic component arises, self-consistently, from the dissociated gas at the apex of the leading bow shocks and the relatively long molecule reformation time. At least 20 bow shocks are required in each lobe, although these may be sub-divided into smaller bows and turbulent shocked regions. The total outflow mechanical power and cooling amounts to over 30L_\\odot, almost half the source's bolometric luminosity. Nevertheless, only about 6% of the clump mass has been set in outward motion by the outflow, allowing a collapse to continue.

M. D. Smith; D. Froebrich; J. Eislöffel

2003-04-03T23:59:59.000Z

399

OUTFLOWS FROM EVOLVED STARS: THE RAPIDLY CHANGING FINGERS OF CRL 618  

SciTech Connect (OSTI)

Our ultimate goal is to probe the nature of the collimator of the outflows in the pre-planetary nebula CRL 618. CRL 618 is uniquely suited for this purpose owing to its multiple, bright, and carefully studied finger-shaped outflows east and west of its nucleus. We compare new Hubble Space Telescope images to images in the same filters observed as much as 11 yr ago to uncover large proper motions and surface brightness changes in its multiple finger-shaped outflows. The expansion age of the ensemble of fingers is close to 100 yr. We find strong brightness variations at the fingertips during the past decade. Deep IR images reveal a multiple ring-like structure of the surrounding medium into which the outflows propagate and interact. Tightly constrained three-dimensional hydrodynamic models link the properties of the fingers to their possible formation histories. We incorporate previously published complementary information to discern whether each of the fingers of CRL 618 are the results of steady, collimated outflows or a brief ejection event that launched a set of bullets about a century ago. Finally, we argue on various physical grounds that fingers of CRL 618 are likely to be the result of a spray of clumps ejected at the nucleus of CRL 618 since any mechanism that form a sustained set of unaligned jets is unprecedented.

Balick, Bruce [Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States); Huarte-Espinosa, Martin [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Frank, Adam; Gomez, Thomas [Astronomy Department, University of Texas, Austin, TX 78731-2330 (United States); Alcolea, Javier [Observatorio Astronomico Nacional (IGN), E-28014 Madrid (Spain); Corradi, Romano L. M. [Instituto de Astrofisica de Canarias, E-38200 La Laguna, Tenerife (Spain); Vinkovic, Dejan, E-mail: balick@uw.edu, E-mail: martinHE@pas.rochester.edu, E-mail: afrank@pas.rochester.edu, E-mail: gomezt@astro.as.utexas.edu, E-mail: j.alcolea@oan.es, E-mail: rcorradi@iac.es, E-mail: vinkovic@pmfst.hr [Physics Department, University of Split, Teslina 12/III, HR-21000 Split (Croatia)

2013-07-20T23:59:59.000Z

400

The Interfacial-Area-Based Relative Permeability Function  

SciTech Connect (OSTI)

CH2M Hill Plateau Remediation Company (CHPRC) requested the services of the Pacific Northwest National Laboratory (PNNL) to provide technical support for the Remediation Decision Support (RDS) activity within the Soil & Groundwater Remediation Project. A portion of the support provided in FY2009, was to extend the soil unsaturated hydraulic conductivity using an alternative approach. This alternative approach incorporates the Brooks and Corey (1964), van Genuchten (1980), and a modified van Genuchten water-retention models into the interfacial-area-based relative permeability model presented by Embid (1997). The general performance of the incorporated models is shown using typical hydraulic parameters. The relative permeability models for the wetting phase were further examined using data from literature. Results indicate that the interfacial-area-based model can describe the relative permeability of the wetting phase reasonably well.

Zhang, Z. F.; Khaleel, Raziuddin

2009-09-25T23:59:59.000Z

Note: This page contains sample records for the topic "outflow fracture permeability" 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.


401

RESEARCH PROGRAM ON FRACTURED PETROLEUM RESERVOIRS  

SciTech Connect (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

402

Experience proves forced fracture closure works  

SciTech Connect (OSTI)

Forced closure, or perhaps better-named ``reverse gravel packing,`` of fractures immediately following hydraulic fracturing with proppant and gelled fluids is a technique which, with rare exception, can be extremely beneficial to the success of almost every hydraulic fracture treatment. By proper planning of the rig-up to allow immediate flow-back, substantial quantities of polymer and load fluid can be removed while simultaneously negating undesirable proppant settling within fractures in the near wellbore area. Fracture smearing (dilution of proppant into an extending fracture) after shutdown can be negated. And in most cases, proppant production from the formation can be reduced. Discussions in the article explain why Ely and Associates has the confidence to make these claims after extensive hydraulic fracturing experience in many geographical areas.

Ely, J.W. [John Ely and Associates, Inc., Houston, TX (United States)

1996-01-01T23:59:59.000Z

403

Process of breaking and rendering permeable a subterranean rock mass  

DOE Patents [OSTI]

The process of the present invention involves the following steps: producing, as by hydrofracing, a substantially horizontal fracture in the subterranean rock mass to be processed; emplacing an explosive charge in the mass in spaced juxtaposed position to the fracture; enlarging the fracture to create a void space thereat, an initial lifting of the overburden, and to provide a free face juxtaposed to and arranged to cooperate with the emplaced explosive charge; and exploding the charge against the free face for fragmenting the rock and to distribute the space, thus providing fractured, pervious, rubble-ized rock in an enclosed subterranean chamber. Firing of the charge provides a further lifting of the overburden, an enlargement of the chamber and a larger void space to distribute throughout the rubble-ized rock within the chamber. In some forms of the invention an explosive charge is used to produce a transitory enlargement of the fracture, and the juxtaposed emplaced charge is fired during the critical period of enlargement of the fracture.

Lekas, Mitchell A. (Concord, CA)

1980-01-01T23:59:59.000Z

404

Effects of Water Injection into Fractured Geothermal Reservoirs: A Summary of Experience Worldwide  

SciTech Connect (OSTI)

Reinjection of water into fractured geothermal reservoirs holds potential both for improvement and degradation of total energy recovery. The replacement of reservoir fluid can mean support of placement of reservoir pressures and also more efficient thermal energy recovery, but at the same time the premature invasion of reinjected water back into production wells through high permeability fractures can reduce discharge enthalpy and hence deliverability and useful energy output. Increases in reservoir pressure and maintenance of field output have been observed in operating fields, but unfortunately so too have premature thermal breakthroughs. The design of reinjection schemes, therefore, requires careful investigation into the likely effects, using field experimentation. This paper summarizes field experience with reinjection around the world, with the intention of elucidating characteristics of possible problems. The results summarized in this paper fall into three categories of interest: permeability changes dye to injection (both increases and decreases); the path followed by injected water (as indicated by tracer tests); and the thermal and hydraulic influences of injection on the reinjection well itself and on surrounding producers. [DJE-2005

Horne, Roland N.

1982-06-01T23:59:59.000Z

405

Upscaling verticle permeability within a fluvio-aeolian reservoir  

SciTech Connect (OSTI)

Vertical permeability (k{sub v}) is a crucial factor in many reservoir engineering issues. To date there has been little work undertaken to understand the wide variation of k{sub v} values measured at different scales in the reservoir. This paper presents the results of a study in which we have modelled the results of a downhole well tester using a statistical model and high resolution permeability data. The work has demonstrates and quantifies a wide variation in k{sub v} at smaller, near wellbore scales and has implications for k{sub v} modelling at larger scales.

Thomas, S.D.; Corbett, P.W.M.; Jensen, J.L. [Heriot-Watt Univ., Edinburgh (United Kingdom)

1997-08-01T23:59:59.000Z

406

Acid Fracture and Fracture Conductivity Study of Field Rock Samples  

E-Print Network [OSTI]

(Black and Hower 1965). Clays consist of negatively charged aluminosilicate layers kept together by cations. The most characteristic property is their ability to adsorb water between the layers, resulting in strong repulsive forces and clay expansion... chemicals used in water fracturing such as friction reducers, fluid-loss additives, and surfactants (Black and Hower 1965). The samples used in this study had significant clay-like content. To prevent swelling, a 2% KCl solution was used throughout...

Underwood, Jarrod

2013-11-15T23:59:59.000Z

407

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

408

VisualizationandHierarchicalAnalysisofFlowinDiscreteFractureNetworkModels Flow and transport in low permeability fractured rock is primary in interconnected fracture networks. Prediction and characterization of ow and transport in fractured rock has impor  

E-Print Network [OSTI]

. A steady-state ow solution for saturated water is obtained using FEHM (Finite Element Heat and Mass resource management, and hydrocarbon extraction. We have developed methods to explicitly model ow ective use of traditional visualization methods. We would also like quantitative analysis methods

Hamann, Bernd

409

Importance of Low Permeability Natural Gas Reservoirs (released in AEO2010)  

Reports and Publications (EIA)

Production from low-permeability reservoirs, including shale gas and tight gas, has become a major source of domestic natural gas supply. In 2008, low-permeability reservoirs accounted for about 40% of natural gas production and about 35% of natural gas consumption in the United States. Permeability is a measure of the rate at which liquids and gases can move through rock. Low-permeability natural gas reservoirs encompass the shale, sandstone, and carbonate formations whose natural permeability is roughly 0.1 millidarcies or below. (Permeability is measured in darcies.)

2010-01-01T23:59:59.000Z

410

Laboratory Study to Identify the Impact of Fracture Design Parameters over the Final Fracture Conductivity Using the Dynamic Fracture Conductivity Test Procedure  

E-Print Network [OSTI]

such as closure stress, and temperature and fracture fluid parameters such as proppant loading over the final conductivity of a hydraulic fracture treatment. With the purpose of estimating the relation between fracture conductivity and the design parameters, two...

Pieve La Rosa, Andres Eduardo

2011-08-08T23:59:59.000Z

411

Acoustic Emission in a Fluid Saturated Hetergeneous Porous Layer with Application to Hydraulic Fracture  

E-Print Network [OSTI]

responses during hydraulic fracturing, and aid developmentFracture Monitoring Hydraulic fracturing is a method forfluids" used for hydraulic fracturing, the above frequencies

Nelson, J.T.

2009-01-01T23:59:59.000Z

412

Permeable Reactive Biobarriers for the Containment of Heavy Metal  

E-Print Network [OSTI]

. Heavy metals are leached as ground water reaches the exposed ores. Arizona has a rich historyPermeable Reactive Biobarriers for the Containment of Heavy Metal Contamination in Acid Mine) is defined as the presence heavy metals, increased acidity, and sulfate as a direct result of mining

Fay, Noah

413

An asymptotic model of seismic reflection from a permeable layer  

SciTech Connect (OSTI)

Analysis of compression wave propagation in a poroelastic medium predicts a peak of reflection from a high-permeability layer in the low-frequency end of the spectrum. An explicit formula expresses the resonant frequency through the elastic moduli of the solid skeleton, the permeability of the reservoir rock, the fluid viscosity and compressibility, and the reservoir thickness. This result is obtained through a low-frequency asymptotic analysis of Biot's model of poroelasticity. A review of the derivation of the main equations from the Hooke's law, momentum and mass balance equations, and Darcy's law suggests an alternative new physical interpretation of some coefficients of the classical poroelasticity. The velocity of wave propagation, the attenuation factor, and the wave number, are expressed in the form of power series with respect to a small dimensionless parameter. The absolute value of this parameter is equal to the product of the kinematic reservoir fluid mobility and the wave frequency. Retaining only the leading terms of the series leads to explicit and relatively simple expressions for the reflection and transmission coefficients for a planar wave crossing an interface between two permeable media, as well as wave reflection from a thin highly-permeable layer (a lens). Practical applications of the obtained asymptotic formulae are seismic modeling, inversion, and at-tribute analysis.

Silin, D.; Goloshubin, G.

2009-10-15T23:59:59.000Z

414

Sediment permeability, distribution, and influence on fluxes in oceanic basement  

E-Print Network [OSTI]

6 Sediment permeability, distribution, and influence on fluxes in oceanic basement Glenn A. Spinelli, Emily R. Giambalvo, and Andrew T. Fisher 6.1 Introduction Sediments blanketing oceanic igneous basement rocks control the communication between fluid within the crust and the oceans. Seafloor sediments

Fisher, Andrew

415

Hydrogen permeability and Integrity of hydrogen transfer pipelines  

E-Print Network [OSTI]

Hydrogen permeability and Integrity of hydrogen transfer pipelines Team: Sudarsanam Suresh Babu, Z Pressure Permeation Testing) Hydrogen Pipeline R&D, Project Review Meeting Oak Ridge National Laboratory direction and review) #12;Outline of the presentation Background Hydrogen delivery through steel pipelines

416

Permeable Interlocking Concrete Pavement (PICP) for Stormwater Management  

E-Print Network [OSTI]

Permeable Interlocking Concrete Pavement (PICP) for Stormwater Management Benefits and Uses Traditional Concrete · Long-term Maintenance Required by Routine Vacuum Sweeping · Sweeping Cost May Be Off-set by Possible Reduction in Deicing Costs · Repairs Can be Made in Freezing Temperatures with Reinstated Concrete

417

Naked-eye optical flash from gamma-ray burst 080319B: Tracing the decaying neutrons in the outflow  

E-Print Network [OSTI]

Naked-eye optical flash from gamma-ray burst 080319B: Tracing the decaying neutrons in the outflow of the GRB emission into the optical band [1], suggesting that the optical and the gamma-ray emissions 2008; published 15 January 2009) For an unsteady baryonic gamma-ray burst (GRB) outflow, the fast

Zhang, Bing

418

Using seismic tomography to characterize fracture systems induced by hydraulic fracturing  

SciTech Connect (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

419

Remediation of a fractured clay soil contaminated with gasoline containing MTBE  

SciTech Connect (OSTI)

Gasoline and other light non-aqueous phase liquids (LNAPLs) released into fractured clay soils initially move by advection of the LNAPL through the fractures. Once advective movement of the LNAPL ceases, dissolution of the gasoline components into the pore water and diffusion into the intact blocks of clay becomes an important transport process. The aqueous-phase flux of each compound in the mixture depends in large part upon its aqueous solubility. For example, a low-solubility compound like isooctane remains primarily in the fracture in the LNAPL. A high-solubility compound, like methyl-tert-butyl ether (MTBE), dissolves readily and may move almost entirely into the clay matrix. The distribution of compounds between the matrix and the fractures will have an important impact on the rate at which the gasoline contaminated soil can be remediated. In this context, the presence of soluble additives like MTBE can significantly impact the risk and remediation time for the, soil. Beginning in 1993 a field study to examine the applicability of air flushing for remediation of low-permeability soils was sponsored by API. The study focused on a variety of soil vapor extraction (SVE) and in situ air sparging (IAS) approaches for mass removal and risk reduction. The source of gasoline contamination in this study was a release of 50 liters of a mixture containing 14 gasoline hydrocarbons ranging from pentane to naphthalene, and including MTBE. The mixture was released into the shallow subsurface and allowed to redistribute for 10 months prior to air flushing startup. Numerical modeling indicated that essentially all of the MTBE should have dissolved into the matrix. In contrast, essentially all of the isooctane should have remained in the LNAPL in the fractures.

Johnson, R.L.; Grady, D.E. [Oregon Graduate Institute, Portland, OR (United States); Walden, T. [BP Oil Europe, Brussels (Belgium)

1997-12-31T23:59:59.000Z

420

Tritium Permeability of Incoloy 800H and Inconel 617  

SciTech Connect (OSTI)

Design of the Next Generation Nuclear Plant (NGNP) reactor and its high-temperature components requires information regarding the permeation of fission generated tritium and hydrogen product through candidate heat exchanger alloys. Release of fission-generated tritium to the environment and the potential contamination of the helium coolant by permeation of product hydrogen into the coolant system represent safety basis and product contamination issues. Of the three potential candidates for high-temperature components of the NGNP reactor design, only permeability for Incoloy 800H has been well documented. Hydrogen permeability data have been published for Inconel 617, but only in two literature reports and for partial pressures of hydrogen greater than one atmosphere, far higher than anticipated in the NGNP reactor. To support engineering design of the NGNP reactor components, the tritium permeability of Inconel 617 and Incoloy 800H was determined using a measurement system designed and fabricated at Idaho National Laboratory. The tritium permeability of Incoloy 800H and Inconel 617, was measured in the temperature range 650 to 950 C and at primary concentrations of 1.5 to 6 parts per million volume tritium in helium. (partial pressures of 10-6 atm) - three orders of magnitude lower partial pressures than used in the hydrogen permeation testing. The measured tritium permeability of Incoloy 800H and Inconel 617 deviated substantially from the values measured for hydrogen. This may be due to instrument offset, system absorption, presence of competing quantities of hydrogen, surface oxides, or other phenomena. Due to the challenge of determining the chemical composition of a mixture with such a low hydrogen isotope concentration, no categorical explanation of this offset has been developed.

Philip Winston; Pattrick Calderoni; Paul Humrickhouse

2011-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "outflow fracture permeability" 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.


421

Tritium Permeability of Incoloy 800H and Inconel 617  

SciTech Connect (OSTI)

Design of the Next Generation Nuclear Plant (NGNP) reactor and its high-temperature components requires information regarding the permeation of fission generated tritium and hydrogen product through candidate heat exchanger alloys. Release of fission-generated tritium to the environment and the potential contamination of the helium coolant by permeation of product hydrogen into the coolant system represent safety basis and product contamination issues. Of the three potential candidates for high-temperature components of the NGNP reactor design, only permeability for Incoloy 800H has been well documented. Hydrogen permeability data have been published for Inconel 617, but only in two literature reports and for partial pressures of hydrogen greater than one atmosphere, far higher than anticipated in the NGNP reactor. To support engineering design of the NGNP reactor components, the tritium permeability of Inconel 617 and Incoloy 800H was determined using a measurement system designed and fabricated at Idaho National Laboratory. The tritium permeability of Incoloy 800H and Inconel 617, was measured in the temperature range 650 to 950°C and at primary concentrations of 1.5 to 6 parts per million volume tritium in helium. (partial pressures of 10-6 atm)—three orders of magnitude lower partial pressures than used in the hydrogen permeation testing. The measured tritium permeability of Incoloy 800H and Inconel 617 deviated substantially from the values measured for hydrogen. This may be due to instrument offset, system absorption, presence of competing quantities of hydrogen, surface oxides, or other phenomena. Due to the challenge of determining the chemical composition of a mixture with such a low hydrogen isotope concentration, no categorical explanation of this offset has been developed.

Philip Winston; Pattrick Calderoni; Paul Humrickhouse

2012-07-01T23:59:59.000Z

422

Fracture induced anisotropy in viscoelastic UNLP, 11 Octubre de 2012  

E-Print Network [OSTI]

Fracture induced anisotropy in viscoelastic media UNLP, 11 Octubre de 2012 . Fracture induced anisotropy in viscoelastic media ­ p. #12;Fractured media. I Fractures are common in the earth's crust due to different factors, for instance, tectonic stresses and natural or artificial hydraulic fracturing caused

Santos, Juan

423

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

424

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

425

LARGE SCALE PERMEABILITY TEST OF THE GRANITE IN THE STRIPA MINE AND THERMAL CONDUCTIVITY TEST  

E-Print Network [OSTI]

PERMEABILITY TEST OF THE GRANITE' IN THE STRIPA MINE AND,PERMEABILITY TEST OF THE GRANITE IN THE STRIPA MINE ANDPERMEABILITY TEST OF THE GRANITE IN THE STRIPA MINE AND

Lundstrom, L.

2011-01-01T23:59:59.000Z

426

E-Print Network 3.0 - arterioso permeable con Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of illite-rich shale... and permeabilities depend on fluid composition. Permeabilities to flow of 1 M CaCl2 are 3-5 times ... Source: Herbert, Bruce - Department of Geology and...

427

DIAGNOSTICS OF AGN-DRIVEN MOLECULAR OUTFLOWS IN ULIRGs FROM HERSCHEL-PACS OBSERVATIONS OF OH AT 119 ?m  

SciTech Connect (OSTI)

We report on our observations of the 79 and 119 ?m doublet transitions of OH for 24 local (z < 0.262) ULIRGs observed with Herschel-PACS as part of the Herschel ULIRG Survey (HERUS). Some OH 119 ?m profiles display a clear P-Cygni shape and therefore imply outflowing OH gas, while other profiles are predominantly in absorption or are completely in emission. We find that the relative strength of the OH emission component decreases as the silicate absorption increases. This result locates the OH outflows inside the obscured nuclei. The maximum outflow velocities for our sources range from less than 100 to ?2000 km s{sup –1}, with 15/24 (10/24) sources showing OH absorption at velocities exceeding 700 km s{sup –1} (1000 km s{sup –1}). Three sources show maximum OH outflow velocities exceeding that of Mrk231. Since outflow velocities above 500-700 km s{sup –1} are thought to require an active galactic nucleus (AGN) to drive them, about two-thirds of our ULIRG sample may host AGN-driven molecular outflows. This finding is supported by the correlation we find between the maximum OH outflow velocity and the IR-derived bolometric AGN luminosity. No such correlation is found with the IR-derived star formation rate. The highest outflow velocities are found among sources that are still deeply embedded. We speculate that the molecular outflows in these sources may be in an early phase of disrupting the nuclear dust veil before these sources evolve into less-obscured AGNs. Four of our sources show high-velocity wings in their [C II] fine-structure line profiles, implying neutral gas outflow masses of at least (2-4.5) × 10{sup 8} M{sub ?}.

Spoon, H. W. W.; Lebouteiller, V. [Cornell University, CRSR, Space Sciences Building, Ithaca, NY 14853 (United States); Farrah, D. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); González-Alfonso, E. [Departamento de Física y Matemáticas, Universidad de Alcalá, Campus Universitario, E-28871 Alcalá de Henares, Madrid (Spain); Bernard-Salas, J. [Department of Physical Sciences, Milton Keynes MK7 6AA (United Kingdom); Urrutia, T. [Leibniz Institut für Astrophysik, Potsdam, An der Sternwarte 16, D-14482 Potsdam (Germany); Rigopoulou, D.; Verma, A. [Department of Physics, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Westmoquette, M. S. [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei München (Germany); Smith, H. A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Afonso, J. [Centro de Astronomia e Astrofísica da Universidade de Lisboa, Observatório Astronómico de Lisboa, Tapada da Ajuda, 1349-018 Lisbon (Portugal); Pearson, C. [RAL Space, Rutherford Appleton Laboratory, Harwell, Oxford OX11 0QX (United Kingdom); Cormier, D. [Institut für theoretische Astrophysik, Zentrum für Astronomie der Universität Heidelberg, Albert-Ueberle Str. 2, D-69120 Heidelberg (Germany); Efstathiou, A. [School of Sciences, European University Cyprus, Diogenes Street, Engomi, 1516 Nicosia (Cyprus); Borys, C. [Infrared Processing and Analysis Center, California Institute of Technology, MS 100-22, Pasadena, CA 91125 (United States); Etxaluze, M. [Departamento de Astrofísica. Centro de Astrobiología. CSIC-INTA. Torrejón de Ardoz, E-28850 Madrid (Spain); Clements, D. L., E-mail: spoon@isc.astro.cornell.edu [Physics Department, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom)

2013-10-01T23:59:59.000Z

428

Hydraulic fracturing in tight, fissured media  

SciTech Connect (OSTI)

Large volumes of natural gas are found in tight, fissured reservoirs. Hydraulic fracturing can enhance recovery, but many complications, such as pressure-sensitive or accelerated leakoff, damage, and complex fracturing, arise during treatment of such reservoirs. This paper reports that special procedures generally should be considered during breakdown and fracturing of these reservoirs. In addition, the use of alternative stimulation strategies may be beneficial.

Warpinski, N.R. (Sandia National Lab., Albuquerque, NM (US))

1991-02-01T23:59:59.000Z

429

Biomass burning emission inventory with daily resolution: Application to aircraft observations of Asian outflow  

E-Print Network [OSTI]

Biomass burning emission inventory with daily resolution: Application to aircraft observations for biomass burning using AVHRR satellite observations of fire activity corrected for data gaps and scan angle biomass burning in SE Asia was a major contributor to the outflow of Asian pollution observed in TRACE

Palmer, Paul

430

The effect of drier outflow temperature on rumen protein degradability and intestinal digestibility of rumen-  

E-Print Network [OSTI]

of rumen- undegraded protein of dehydrated grass and lucerne ZM Kowalski PMP Pisulewski2 JL Peyraud J was to determine the effect of drier outflow temperature (123, 133, 143 and 153°C) on dehydrated grass and lucerne and increased ADIN % N in dehydrated grass. These tendencies were not seen for dehydrated lucerne. Temperature

Paris-Sud XI, Université de

431

A dynamical model of supernova feedback: gas outflows from the interstellar medium  

E-Print Network [OSTI]

We present a dynamical model of supernova feedback which follows the evolution of pressurised bubbles driven by supernovae in a multi-phase interstellar medium (ISM). The bubbles are followed until the point of break-out into the halo, starting from an initial adiabatic phase to a radiative phase. We show that a key property which sets the fate of bubbles in the ISM is the gas surface density, through the work done by the expansion of bubbles and its role in setting the gas scaleheight. The multi-phase description of the ISM is essential, and neglecting it leads to order of magnitude differences in the predicted outflow rates. We compare our predicted mass loading and outflow velocities to observations of local and high-redshift galaxies and find good agreement. With the aim of analysing the dependence of the mass loading of the outflow, $\\beta$ (i.e. the ratio between the outflow and star formation rates), on galaxy properties, we embed our model in the galaxy formation simulation, GALFORM, set in the $\\Lamb...

Lagos, Claudia; Baugh, C M

2013-01-01T23:59:59.000Z

432

Chemical Abundances in AGN Environment: X-Ray/UV Campaign on the MRK 279 Outflow  

E-Print Network [OSTI]

We present the first reliable determination of chemical abundances in an AGN outflow. The abundances are extracted from the deep and simultaneous FUSE and HST/STIS observations of Mrk 279. This data set is exceptional for its high signal-to-noise, unblended doublet troughs and little Galactic absorption contamination. These attributes allow us to solve for the velocity-dependent covering fraction, and therefore obtain reliable column densities for many ionic species. For the first time we have enough such column densities to simultaneously determine the ionization equilibrium and abundances in the flow. Our analysis uses the full spectral information embedded in these high-resolution data. Slicing a given trough into many independent outflow elements yields the extra constraints needed for a physically meaningful abundances determination. We find that relative to solar the abundances in the Mrk 279 outflow are (linear scaling): carbon 2.2+/-0.7, nitrogen 3.5+/-1.1 and oxygen 1.6+/-0.8. Our UV-based photoionization and abundances results are in good agreement with the independent analysis of the simultaneous Mrk 279 X-ray spectra. This is the best agreement between the UV and X-ray analyses of the same outflow to date.

Nahum Arav; Jack R. Gabel; Kirk T. Korista; Jelle S. Kaastra; Gerard A. Kriss; Ehud Behar; Elisa Costantini; C. Martin Gaskell; Ari Laor; Nalaka Kodituwakku; Daniel Proga; Masao Sako; Jennifer E. Scott; Katrien C. Steenbrugge

2006-11-29T23:59:59.000Z

433

Measurements of Outflow Velocities in On-Disk Plumes from EIS Hinode Observations  

E-Print Network [OSTI]

The contribution of plumes to the solar wind has been subject to hot debate in the past decades. The EUV Imaging Spectrometer (EIS) on board Hinode provides a unique means to deduce outflow velocities at coronal heights via direct Doppler shift measurements of coronal emission lines. Such direct Doppler shift measurements were not possible with previous spectrometers. We measure the outflow velocity at coronal heights in several on-disk long-duration plumes, which are located in coronal holes and show significant blue shifts throughout the entire observational period. In one case, a plume is measured 4 hours apart. The deduced outflow velocities are consistent, suggesting that the flows are quasi-steady. Furthermore, we provide an outflow velocity profile along the plumes, finding that the velocity corrected for the line-of-sight effect can reach 10 km s$^{-1}$ at 1.02 $R_{\\odot}$, 15 km s$^{-1}$ at 1.03 $R_{\\odot}$, and 25 km s$^{-1}$ at 1.05 $R_{\\odot}$. This clear signature of steady acceleration, combined...

Fu, Hui; Li, Bo; Huang, Zhenghua; Jiao, Fangran; Mou, Chaozhou

2014-01-01T23:59:59.000Z

434

Improved quantification of Chinese carbon fluxes using CO2//CO correlations in Asian outflow  

E-Print Network [OSTI]

increases in Chinese anthropogenic CO2 emissions and would also imply a further reduction of the Chinese budget including, in particular, Chinese emissions. The CO2/CO emission ratio varies with the sourceImproved quantification of Chinese carbon fluxes using CO2//CO correlations in Asian outflow

Palmer, Paul

435

Wave Propagation in Fractured Poroelastic Media  

E-Print Network [OSTI]

Wave Propagation in Fractured. Poroelastic Media. WCCM, Barcelona, Spain, July 2014. Juan E. Santos,. 1. 1. Instituto del Gas y del Petr´oleo (IGPUBA), UBA,

2014-06-22T23:59:59.000Z

436

Method of fracturing a geological formation  

DOE Patents [OSTI]

An improved method of fracturing a geological formation surrounding a well bore is disclosed. A relatively small explosive charge is emplaced in a well bore and the bore is subsequently hydraulically pressurized to a pressure less than the formation breakdown pressure and preferably greater than the fracture propagation pressure of the formation. The charge is denoted while the bore is so pressurized, resulting in the formation of multiple fractures in the surrounding formation with little or no accompanying formation damage. Subsequent hydraulic pressurization can be used to propagate and extend the fractures in a conventional manner. The method is useful for stimulating production of oil, gas and possibly water from suitable geologic formations.

Johnson, James O. (2679-B Walnut, Los Alamos, NM 87544)

1990-01-01T23:59:59.000Z

437

Fracture characteristics and their relationships to producing...  

Open Energy Info (EERE)

area Jump to: navigation, search OpenEI Reference LibraryAdd to library Book: Fracture characteristics and their relationships to producing zones in deep wells, Raft River...

438

Geothermal: Sponsored by OSTI -- Fracture Characterization in...  

Office of Scientific and Technical Information (OSTI)

Fracture Characterization in Enhanced Geothermal Systems by Wellbore and Reservoir Analysis Geothermal Technologies Legacy Collection HelpFAQ | Site Map | Contact Us | Admin Log...

439

Seismic Fracture Characterization Methods for Enhanced Geothermal...  

Broader source: Energy.gov (indexed) [DOE]

5 4.5.2 Seismic Fracture Characterization Methods for Enhanced Geothermal Systems Presentation Number: 022 Investigator: Queen, John (Hi-Q Geophysical Inc.) Objectives: To develop...

440

Microseismic Tracer Particles for Hydraulic Fracturing  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

can be discriminateddetected that correspond to only the portion of the hydraulic fracture that contains the proppant material and can be expected to be conductive to the flow...

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441

Microearthquake Technology for EGS Fracture Characterization...  

Broader source: Energy.gov (indexed) [DOE]

1 4.5.1 Microearthquake Technology for EGS Fracture Characterization Presentation Number: 021 Investigator: Foulger, Gillian (Foulger Consulting) Objectives: To understand how EGS...

442

Naturally fractured tight gas reservoir detection optimization  

SciTech Connect (OSTI)

The work plan for the quarter of October 1, 1997--December 31, 1997 consisted of two tasks: (1) Present results of Rulison field test at various conferences, seminars, and to Barrett Resources and Snyder Oil Co. and (2) Continue work into developing a predictive quantitative method for locating fault-related natural fractures. The first task was completed during this reporting period. The second task continues the beginning of quantitative fracture mechanics analysis of the geologic processes that are involved for the development of fault-related natural fractures. The goal of this work is to develop a predictive capability of locating natural fractures prior to drilling.

NONE

1998-09-30T23:59:59.000Z

443

Research consortium on fractured petroleum reservoirs. Third quarterly report, July 1--September 30, 1993  

SciTech Connect (OSTI)

Our 1993 third quarter report discusses the results of our work on: (1) gas-oil gravity drainage in layered media; and, (2) the influence of viscous forces on gas-oil flow in fractured porous media. For sometime, we have been working on the incorporation of reinfiltration and capillary continuity concepts in a dual-porosity model. A simple and accurate technique has been developed for this purpose. The experiments on gas-oil gravity drainage in layered media are intended to: (1) verify our theoretical analysis; (2) provide more insight; and, (3) provide a guide for the simulation of gas-oil gravity drainage at field scale. On the first objective, the experiments confirm that gas-oil gravity drainage could result in a downward gas fingering phenomenon. Without capillary pressure, downward gas fingering could not realize. The experiments also show that drainage from a less permeable layer would be an extremely slow process. This is similar to the drainage performance of matrix blocks in fractured porous media. Apparently, relative permeability to gas (i.e. gas mobility) may be important for flow in layered porous media. The project on the effect of viscous forces on gas-oil displacement in fractured porous media has taken longer than anticipated. For the first time, in gravity drainage experiments of the matrix-fracture configuration used in this project, we could not obtain reproducible results. After several tests, we teamed that the surface tension of the normal-decane/air system changes in the presence of the coating cover which was used in the experimental assembly of this project. We removed the coating. The experiments can now be reproduced. The data show that there is a strong effect of viscous forces on matrix/fracture flow. A small imposed pressure gradient results in a substantial amount of oil recovery. After performing 3-4 more tests, the data will be analyzed and an appropriate model will be developed to relate experimental data to field conditions.

Firoozabadi, A.; Markeset, T.

1993-11-22T23:59:59.000Z

444

Geometrical and transport properties of single fractures: influence of the roughness of the fracture  

E-Print Network [OSTI]

Geometrical and transport properties of single fractures: influence of the roughness of the fracture walls H. Auradou Univ Pierre et Marie Curie-Paris6, Univ Paris-Sud, CNRS, F-91405. Lab FAST, Bat reviews the main features of the transport properties of single fractures. A particular attention paid

Paris-Sud XI, Université de

445

Outflow Feedback Regulated Massive Star Formation in Parsec-Scale Cluster Forming Clumps  

SciTech Connect (OSTI)

We investigate massive star formation in turbulent, magnetized, parsec-scale clumps of molecular clouds including protostellar outflow feedback using three dimensional numerical simulations of effective resolution 2048{sup 3}. The calculations are carried out using a block structured adaptive mesh refinement code that solves the ideal MHD equations including self-gravity and implements accreting sink particles. We find that, in the absence of regulation by magnetic fields and outflow feedback, massive stars form readily in a turbulent, moderately condensed clump of {approx} 1,600 M{sub {circle_dot}} (containing {approx} 10{sup 2} initial Jeans masses), along with a cluster of hundreds of lower mass stars. The massive stars are fed at high rates by (1) transient dense filaments produced by large-scale turbulent compression at early times, and (2) by the clump-wide global collapse resulting from turbulence decay at late times. In both cases, the bulk of the massive star's mass is supplied from outside a 0.1 pc-sized 'core' that surrounds the star. In our simulation, the massive star is clump-fed rather than core-fed. The need for large-scale feeding makes the massive star formation prone to regulation by outflow feedback, which directly opposes the feeding processes. The outflows reduce the mass accretion rates onto the massive stars by breaking up the dense filaments that feed the massive star formation at early times, and by collectively slowing down the global collapse that fuel the massive star formation at late times. The latter is aided by a moderate magnetic field of strength in the observed range (corresponding to a dimensionless clump mass-to-flux ratio {lambda} {approx} a few); the field allows the outflow momenta to be deposited more efficiently inside the clump. We conclude that the massive star formation in our simulated turbulent, magnetized, parsec-scale clump is outflow-regulated and clump-fed (ORCF for short). An important implication is that the formation of low-mass stars in a dense clump can affect the formation of massive stars in the same clump, through their outflow feedback on the clump dynamics. In a companion paper, we discuss the properties of the lower mass cluster members formed along with the massive stars, including their mass distribution and spatial clustering.

Wang, Peng; /KIPAC, Menlo Park /Stanford U., Phys.Dept.; Li, Zhi-Yun; /Virginia U., Astron. Dept.; Abel, Tom; /KIPAC, Menlo Park /Stanford U., Phys.Dept.; Nakamura, Fumitaka; /Niigata U.

2010-02-15T23:59:59.000Z

446

STRENGTH AND PERMEABILITY TESTS ON ULTRA-LARGE STRIPA GRANITE CORE  

E-Print Network [OSTI]

granite • • • • • • • • • • • '. • • • • • • • • • • • • •· . . Mohr diagram for intact Stripa granite . .healed fractures in Stripa granite. · . · . . Key to figures

Thorpe, R.

2009-01-01T23:59:59.000Z

447

Laboratory-scale fracture conductivity created by acid etching  

E-Print Network [OSTI]

Success of acid fracturing treatment depends greatly on the created conductivity under closure stress. In order to have sufficient conductivity, the fracture face must be non-uniformly etched while the fracture strength maintained to withstand...

Pournik, Maysam

2009-05-15T23:59:59.000Z

448

FINITE FRACTURE MECHANICS OF MATRIX MICROCRACKING IN COMPOSITES  

E-Print Network [OSTI]

FINITE FRACTURE MECHANICS OF MATRIX MICROCRACKING IN COMPOSITES JOHN A. NAIRN INTRODUCTION damage following complex loading conditions. This chapter describes a fracture mechanics approach to the microcracking problem. A complicating feature of composite fracture mechanics analysis is that laminates often

Nairn, John A.

449

Seismic characterization of fractured reservoirs using 3D double beams  

E-Print Network [OSTI]

We propose an efficient target-oriented method to characterize seismic properties of fractured reservoirs: the spacing between fractures and the fracture orientation. We use both singly scattered and multiply scattered ...

Zheng, Yingcai

2012-01-01T23:59:59.000Z

450

Ductile fracture modeling : theory, experimental investigation and numerical verification  

E-Print Network [OSTI]

The fracture initiation in ductile materials is governed by the damaging process along the plastic loading path. A new damage plasticity model for ductile fracture is proposed. Experimental results show that fracture ...

Xue, Liang, 1973-

2007-01-01T23:59:59.000Z

451

Numerical simulation of hydraulic fracturing  

E-Print Network [OSTI]

of Eq. 21, in its present form, is unstable. The change in fracture cell volume over the time step, BV/At, must be known to calculate pressures at the new time level. Since the value of the AV/At term is dependent on the pressure being solved for... is unconditionally stable and, therefore, guarantees a solution for any time step size~s. To implicitly expand the AV/At term, the pressure change component Ap /At must be extracted so that pex(t+At) can be placed ex on the left hand side of Eq. 21. The AV...

Warner, Joseph Barnes

1987-01-01T23:59:59.000Z

452

Spontaneous Imbibition in Low Permeability Medium, SUPRI TR-114  

SciTech Connect (OSTI)

A systematic experimental investigation of capillary pressure characteristics and fluid flow in diatomite was begun. Using an X-ray CT scanner and a specially constructed imbibition cell, we study spontaneous water imbibition processes in diatomite and, for reference, Berea sandstone and chalk. The mass of water imbibed as a function of time is also measured. Imbibition is restricted to concurrent flow. Despite a marked difference in rock properties such as permeability and porosity, we find similar trends in saturation profiles and weight gain versus time functions. Imbibition in diatomote is relatively rapid when initial water saturation is low due to large capillary forces. Using a non-linear regression analysis together with the experimental data, the capillary pressure and water relative permeability curves are determined for the diatomite in the water-air system. The results given for displacement profiles by numerical simulation match the experimental results.

Kovscek, Anthony R.; Schembre, Josephina

1999-08-09T23:59:59.000Z

453

Tubular hydrogen permeable metal foil membrane and method of fabrication  

DOE Patents [OSTI]

A tubular hydrogen permeable metal membrane and fabrication process comprises obtaining a metal alloy foil having two surfaces, coating the surfaces with a metal or metal alloy catalytic layer to produce a hydrogen permeable metal membrane, sizing the membrane into a sheet with two long edges, wrapping the membrane around an elongated expandable rod with the two long edges aligned and overlapping to facilitate welding of the two together, placing the foil wrapped rod into a surrounding fixture housing with the two aligned and overlapping foil edges accessible through an elongated aperture in the surrounding fixture housing, expanding the elongated expandable rod within the surrounding fixture housing to tighten the foil about the expanded rod, welding the two long overlapping foil edges to one another generating a tubular membrane, and removing the tubular membrane from within the surrounding fixture housing and the expandable rod from with the tubular membrane.

Paglieri, Stephen N.; Birdsell, Stephen A.; Barbero, Robert S.; Snow, Ronny C.; Smith, Frank M.

2006-04-04T23:59:59.000Z

454

Methodologies and new user interfaces to optimize hydraulic fracturing design and evaluate fracturing performance for gas wells  

E-Print Network [OSTI]

program. The main contributions of this work are: An optimal fracture design methodology called unified fracture design (UFD) is presented and damage effects are considered in the optimal design calculation. As a by-product of UFD, a fracture evaluation...

Wang, Wenxin

2006-04-12T23:59:59.000Z

455

Semi-analytical estimates of permeability obtained from capillary pressure  

E-Print Network [OSTI]

..............................................................................................................................................(2.7) Where ? is the pore size distribution index. This model is commonly used for consolidated porous media. In 1980, Van Genuchten26 adopted a capillary pressure model to predict the hydraulic conductivity of unsaturated soils. Van... on permeability and its prediction ? the first part of the derivation follows the work of Wyllie and Gardner.3 Their model describes the porous media as a bundle of capillary tubes featuring a random connection of pore spaces. Some of the assumptions made are...

Huet, Caroline Cecile

2006-04-12T23:59:59.000Z