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Note: This page contains sample records for the topic "highly fractured continuous" from the National Library of EnergyBeta (NLEBeta).
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1

High velocity impact fracture  

E-Print Network (OSTI)

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

Teng, Xiaoqing

2005-01-01T23:59:59.000Z

2

Permeability enhancement using high energy gas fracturing  

DOE Green Energy (OSTI)

This paper reports the results of a preliminary study of using High Energy Gas Fracturing (HEGF) techniques for geothermal well stimulation. Experiments conducted in the G-tunnel complex at the Nevada Test Site (NTS) showed that multiple fractures could be created in water-filled boreholes using HEGF. Therefore, the method is potentially useful for geothermal well stimulation. 4 refs., 11 figs.

Chu, T.Y.; Cuderman, J.F.; Jung, J.; Jacobson, R.D.

1986-01-01T23:59:59.000Z

3

High-Speed Fracture Phenomena of Glass Bottle by Underwater ...  

Science Conference Proceedings (OSTI)

Presentation Title, High-Speed Fracture Phenomena of Glass Bottle by Underwater Shock Wave. Author(s), Hidetoshi Sakamoto, Shinjirou Kawabe, Yoshifumi ...

4

High-permeability fracturing: The evolution of a technology  

SciTech Connect

Since its introduction almost 50 years ago, hydraulic fracturing has been the prime engineering tool for improving well productivity either by bypassing near-wellbore damage or by actually stimulating performance. Historically (and in many instances erroneously), the emphasis for propped fracturing was on fracture length, culminating in massive treatments for tight-gas sands with several million pounds of proppant and design lengths in excess of 1,500 ft. More recently, the importance of fracture conductivity has become appreciated. This paper uses field examples to trace the history, development, and application of TSO fracturing to high-permeability formations, including fracturing to increase PI, as well as applications aimed at improving completions in unconsolidated sands. Potential applications of fracturing to bypass the need for sand control are explored. Finally, the use of fracturing as a reservoir-management tool is examined through use of a propped fracture to alter the vertical flow profile of a well to maximize reserves. This particular use of fracturing leads to cases where careful design of both fracture length and conductivity is required; i.e., too much conductivity is as damaging to reservoir management as too little.

Smith, M.B.; Hannah, R.R.

1996-07-01T23:59:59.000Z

5

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

E-Print Network (OSTI)

fracture model for multiphase ?ow in porous media. AIChEsingle- and multiphase transport in fractured porous media

Geiger, S.

2012-01-01T23:59:59.000Z

6

Proppant Fracture Conductivity with High Proppant Loading and High Closure Stress  

E-Print Network (OSTI)

Ultra-deepwater reservoirs are important unconventional reservoirs that hold the potential to produce billions of barrels of hydrocarbons, but also present major challenges. This type of reservoir is usually high pressure and high temperature (HPHT) and has a relatively high permeability. Hydraulic fracturing high permeability reservoirs are different from the hydraulic fracturing technology used in low permeability formations. The main purpose of hydraulic fracturing in low permeability reservoirs is to create a long, highly conductive path, whereas in high permeability formations hydraulic fracturing is used predominantly to bypass near wellbore formation damage, control sand production and reduce near wellbore pressure drop. Hydraulically fracturing these types of wells requires short fractures packed with high proppant concentrations. In addition, fracturing in high permeability reservoirs aims at achieving enough fracture length to increase productivity, especially when the viscosity of the reservoir fluid is high. In order to pump such a job and ensure long term productivity from the fracture, understanding the behavior of the fracture fluid and proppant is critical. A series of laboratory experiments have been conducted to study conductivity and fracture width with high proppant loading, high temperature and high pressure. Proppant was manually placed in the fracture and fracture fluid was pumped through the pack. Conductivity was measured by pumping oil to simulate reservoir conditions. Proppant performance and fracture fluids, which carry the proppant into the fracture, and their subsequent clean-up during production, were studied. High strength proppant is ideal for deep fracture stimulations and in this study different proppant loadings at different stresses were tested to see the impact of crushing and fracture width reduction on fracture conductivity. The preliminary test results indicated that oil at reservoir conditions improves clean-up of fracture fluid left in the proppant pack compared with using water at ambient temperature. Increasing the proppant concentration in the fracture showed higher conductivity values in some cases even at high closure stress. The increase in effective closure stress with high temperature resulted in a significant loss in conductivity. Additionally, the fracture width decreased with time and increased effective closure stress. Tests were also run to study the effect of cyclic loading which is expected to further decrease conductivity.

Rivers, Matthew Charles

2010-05-01T23:59:59.000Z

7

Pressure testing of a high temperature naturally fractured reservoir  

DOE Green Energy (OSTI)

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

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

1986-01-01T23:59:59.000Z

8

Fracturing fluid high-temperature breaker for improving well performance  

Science Conference Proceedings (OSTI)

Oxidative breakers are currently being used in fracturing treatments to reduce polymeric gel damage in high-temperature reservoirs. Dissolved high-temperature oxidative breakers are very reactive at high temperatures (275 to 350 F), typically requiring less than 0.25 lbm/1,000 gal of fluid. Recent introduction of a new nonpersulfate oxidative high-temperature encapsulated breaker (HTEB) provides controlled degradation of the fracturing fluid polymers. Laboratory tests show viscosity reduction and delayed release of active oxidizer breaker. HTEB conductivity data show a two-fold increase in retained permeability at 300 F in a borate-crosslinked fluid system.

McConnell, B.

1994-05-01T23:59:59.000Z

9

Fracturing of simulated high-level waste glass in canisters  

SciTech Connect

Waste-glass castings generated from engineering-scale developmental processes at the Pacific Northwest Laboratory are generally found to have significant levels of cracks. The causes and extent of fracturing in full-scale canisters of waste glass as a result of cooling and accidental impact are discussed. Although the effects of cracking on waste-form performance in a repository are not well understood, cracks in waste forms can potentially increase leaching surface area. If cracks are minimized or absent in the waste-glass canisters, the potential for radionuclide release from the canister package can be reduced. Additional work on the effects of cracks on leaching of glass is needed. In addition to investigating the extent of fracturing of glass in waste-glass canisters, methods to reduce cracking by controlling cooling conditions were explored. Overall, the study shows that the extent of glass cracking in full-scale, passively-cooled, continuous melting-produced canisters is strongly dependent on the cooling rate. This observation agrees with results of previously reported Pacific Northwest Laboratory experiments on bench-scale annealed canisters. Thus, the cause of cracking is principally bulk thermal stresses. Fracture damage resulting from shearing at the glass/metal interface also contributes to cracking, more so in stainless steel canisters than in carbon steel canisters. This effect can be reduced or eliminated with a graphite coating applied to the inside of the canister. Thermal fracturing can be controlled by using a fixed amount of insulation for filling and cooling of canisters. In order to maintain production rates, a small amount of additional facility space is needed to accomodate slow-cooling canisters. Alternatively, faster cooling can be achieved using the multi-staged approach. Additional development is needed before this approach can be used on full-scale (60-cm) canisters.

Peters, R.D.; Slate, S.C.

1981-09-01T23:59:59.000Z

10

Fracture behavior of kaolin-reinforced high density polyethylene  

SciTech Connect

The addition of the low-cost mineral filler kaolin to high-density polyethylene (HDPE) creates a composite with both improved stiffness and toughness properties. This study focuses on two aspects of the toughness of these composites: the fracture toughness increment produced by work at the fracture surface and the directionality induced by the injection molding fabrication process. The Essential Work of Fracture (EWF) method gives results which show that a higher volume fraction of kaolin produces more surface work, consistent with earlier work using Compact Tension (CT) tests. The EWF method also demonstrates that a lower volume fraction can produce a higher overall plastic work and apparent toughness. A heat treatment that removes the orientation of the matrix but not that of the particles was applied to study the effect of matrix crystallinity. The results indicate that the matrix supramolecular structure (crystallinity and skin-core effect) is responsible for the directionality of toughness, and that a heat treatment can be used to produce high toughness behavior in both major directions.

Wetherhold, R.C.; Mouzakis, D.E.

1999-10-01T23:59:59.000Z

11

Fracture Mechanics Investigations on High-Temperature Gas-Cooled Reactor Materials  

Science Conference Proceedings (OSTI)

C.5. Fracture Mechanic / Status of Metallic Materials Development for Application in Advanced High-Temperature Gas-Cooled Reactor / Material

Klaus Krompholz; Erik Bodmann; Günter K. H. Gnirss; Horst Huthmann

12

Fracture and Impact Properties of HT-9 Steel Irradiated to High Dose ...  

Science Conference Proceedings (OSTI)

Presentation Title, Fracture and Impact Properties of HT-9 Steel Irradiated to High ... 250, and the irradiation temperature in a servo-hydraulic testing machine.

13

High energy gas fracture experiments in liquid-filled boreholes: potential geothermal application  

SciTech Connect

High Energy Gas Fracturing is a tailored pulse fracturing technique which uses propellants to obtain controlled fracture initiation and extension. Borehole pressurization rates can be tailored, by suitable choice of propellants, to produce four or eight fractures radiating from the wellbore. High Energy Gas Fracture (HEGF) research is conducted at DOE's Nevada Test Site (NTS) in a tunnel complex where experiments can be done under realistic in situ stress conditions (1400 psi (9.7 MPa) overburden stress). Pressure measurements are made in the test borehole during all fracturing experiments. Experiments are mined back to provide direct observation of fracturing obtained. The initial objective of HEGF research was to develop multiple fracturing technology for application in gas well stimulation. HEGF research at NTS and in Devonian shale demonstration tests has resulted in a completed technology for multiple fracturing in uncased, liquid-free wellbores. Current resarch is directed toward extending the technique to liquid-filled boreholes for application in geothermal in addition to gas and oil wells. For liquid-free boreholes, multiple fracturing is specified in terms of pressure risetime required for a given borehole diameter. Propellants are mixed to achieve the desired risetime using a semiempirical mixing equation. The same techniques were successfully applied to fracturing in liquid-filled wellbores. However, the addition of liquid in the borehole results in a significantly more complicated fracturing behavior. Hydrodynamic effects are significant. Multiple fractures are initiated but only some propagated. Multiple- and hydraulic-type fracturing and wellbore crushing have been observed in the same experiment. The potential of using HEGB for geothermal well stimulation has been demonstrated through the present experiments. 18 refs., 40 figs., 4 tabs.

Cuderman, J.F.; Chu, T.Y.; Jung, J.; Jacobson, R.D.

1986-07-01T23:59:59.000Z

14

High Power Superconducting Continuous Wave Linacs for Protons and  

Office of Science (SC) Website

Power Superconducting Continuous Power Superconducting Continuous Wave Linacs for Protons and Heavy-Ions Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Spinoff Applications Spinoff Archives SBIR/STTR Applications of Nuclear Science and Technology Funding Opportunities Nuclear Science Advisory Committee (NSAC) News & Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: sc.np@science.doe.gov More Information » Spinoff Archives High Power Superconducting Continuous Wave Linacs for Protons and Heavy-Ions Print Text Size: A A A RSS Feeds FeedbackShare Page Application/instrumentation: High Power Superconducting Continuous Wave Linacs for Protons and Heavy-Ions

15

Hydraulic fracturing-1  

Science Conference Proceedings (OSTI)

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

Not Available

1990-01-01T23:59:59.000Z

16

High voltage gas insulated transmission line with continuous particle trapping  

DOE Patents (OSTI)

This invention provides a novel high voltage gas insulated transmission line utilizing insulating supports spaced at intervals with snap-in means for supporting a continuous trapping apparatus and said trapping apparatus having perforations and cutouts to facilitate trapping of contaminating particles and system flexibility.

Cookson, Alan H. (Pittsburgh, PA); Dale, Steinar J. (Monroeville, PA)

1983-01-01T23:59:59.000Z

17

D18: Fracture Behavior of High Strength Stainless Steel Wire Rope ...  

Science Conference Proceedings (OSTI)

In order to develop new ways to improve the fatigue life of the high strength stainless steel wire rope, the study on the fracture behavior under fatigue test is basic ...

18

Economic Recovery of Oil Trapped at Fan Margins Using High Angle Wells Multiple Hydraulic Fractures  

SciTech Connect

This project attempts to demonstrate the effectiveness of exploiting thin-layered, low-energy deposits at the distal margin of a prograding turbidite complex through the use of hydraulically fractured horizontal or high-angle wells. The combination of a horizontal or high-angle well and hydraulic fracturing will allow greater pay exposure than can be achieved with conventional vertical wells while maintaining vertical communication between thin interbedded layers and the wellbore. A high-angle well will be drilled in the fan-margin portion of a slope-basin clastic reservoir and will be completed with multiple hydraulic-fracture treatments. Geologic modeling, reservoir characterization, and fine-grid reservoir simulation will be used to select the well location and orientation. Design parameters for the hydraulic-fracture treatments will be determined, in part, by fracturing an existing test well. Fracture azimuth will be predicted by passive seismic monitoring of a fracture-stimulation treatment in the test well using logging tools in an offset well.

Mike L. Laue

1997-10-30T23:59:59.000Z

19

ECONOMIC RECOVERY OF OIL TRAPPED AT FAN MARGINS USING HIGH ANGLE WELLS AND MULTIPLE HYDRAULIC FRACTURES  

Science Conference Proceedings (OSTI)

This project attempts to demonstrate the effectiveness of exploiting thin-layered, low-energy deposits at the distal margin of a prograding turbidite complex through the use of hydraulically fractured horizontal or high-angle wells. The combination of a horizontal or high-angle well and hydraulic fracturing will allow greater pay exposure than can be achieved with conventional vertical wells while maintaining vertical communication between thin interbedded layers and the wellbore. A high-angle well will be drilled in the fan-margin portion of a slope-basin clastic reservoir and will be completed with multiple hydraulic-fracture treatments. Geologic modeling, reservoir characterization, and fine-grid reservoir simulation will be used to select the well location and orientation. Design parameters for the hydraulic-fracture treatments will be determined, in part, by fracturing an existing test well. Fracture azimuth will be predicted by passive seismic monitoring of a fracture-stimulation treatment in the test well using logging tools in an offset well.

Mike L. Laue

1998-11-06T23:59:59.000Z

20

Economic Recovery of Oil Trapped at Fan Margins Using High Angle Wells and Multiple Hydraulic Fractures  

Science Conference Proceedings (OSTI)

This project attempts to demonstrate the effectiveness of exploiting thin-layered, low-energy deposits at the distal margin of a propagating turbidite complex through the use of hydraulically-fractured horizontal or high-angle wells. The combination of a horizontal or high-angled well and hydraulic fracturing will allow greater pay exposure than can be achieved with conventional vertical wells while maintaining vertical communication between thininterbedded layers and the well bore.

Mike L. Laue

1997-05-08T23:59:59.000Z

Note: This page contains sample records for the topic "highly fractured continuous" 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

Economic Recovery of Oil Trapped at Fan Margins Using High Angle Wells and Multiple Hydraulic Fractures  

Science Conference Proceedings (OSTI)

This project attempts to demonstrate the effectiveness of exploiting thin-layered, low energy deposits at the distal end of a protruding turbidite complex through use of hydraulically fractured horizontal of high-angle wells. The combination of a horizontal or high-angle well and hydraulic fracturing will allow greater pay exposure than conventional vertical wells while maintaining vertical communication between thin interbedded layers and the well bore.

Mike L. Laue

1998-05-29T23:59:59.000Z

22

Economic Recovery of Oil Trapped at Fan Margins Using High Angle Wells and Multiple Hydraulic Fractures  

Science Conference Proceedings (OSTI)

This project attempts to demonstrate the effectiveness of exploiting thin-layered, low-energy deposits at the distal margin of a prograding turbidite complex through the use of hydraulically fractured horizontal or high-angle wells. The combination of a horizontal or high-angle well and hydraulic fracturing will allow greater pay exposure than can be achieved with conventional vertical wells while maintaining vertical communication between thin interbedded layers and the wellbore.

Laue, M.L.

1999-11-01T23:59:59.000Z

23

High-bandwidth continuous-flow arc furnace  

DOE Patents (OSTI)

A high-bandwidth continuous-flow arc furnace for stream welding applications includes a metal mass contained in a crucible having an orifice. A power source charges an electrode for generating an arc between the electrode and the mass. The arc heats the metal mass to a molten state. A pressurized gas source propels the molten metal mass through the crucible orifice in a continuous stream. As the metal is ejected, a metal feeder replenishes the molten metal bath. A control system regulates the electrode current, shielding gas pressure, and metal source to provide a continuous flow of molten metal at the crucible orifice. Independent control over the electrode current and shield gas pressure decouples the metal flow temperature and the molten metal flow rate, improving control over resultant weld characteristics. 4 figs.

Hardt, D.E.; Lee, S.G.

1996-08-06T23:59:59.000Z

24

ECONOMIC RECOVERY OF OIL TRAPPED AT FAN MARGINS USING HIGH ANGLE WELLS AND MULTIPLE HYDRAULIC FRACTURES  

Science Conference Proceedings (OSTI)

This project attempts to demonstrate the effectiveness of exploiting thin-layered, low-energy deposits at the distal margin of a prograding turbidite complex through the use of hydraulically fractured horizontal or high-angle wells. The combination of a horizontal or high-angle well and hydraulic fracturing will allow greater pay exposure than can be achieved with conventional vertical wells while maintaining vertical communication between thin interbedded layers and the wellbore. A high-angle well will be drilled in the fan-margin portion of a slope-basin clastic reservoir and will be completed with multiple hydraulic-fracture treatments. Geologic modeling, reservoir characterization, and fine-grid reservoir simulation will be used to select the well location and orientation. Design parameters for the hydraulic-fracture treatments will be determined, in part, by fracturing an existing test well. Fracture azimuth will be predicted by passive seismic monitoring of a fracture-stimulation treatment in the test well using logging tools in an offset well. The long radius, near horizontal well was drilled during the first quarter of 1996. Well conditions resulted in the 7 in. production liner sticking approximately 900 ft off bottom. Therefore, a 5 in. production liner was necessary to case this portion of the target formation. Swept-out sand intervals and a poor cement bond behind the 5 in. liner precluded two of the three originally planned hydraulic fracture treatments. As a result, all pay intervals behind the 5 in. liner were perforated and stimulated with a non-acid reactive fluid. Following a short production period, the remaining pay intervals in the well (behind the 7 in. liner) were perforated. The well was returned to production to observe production trends and pressure behavior and assess the need to stimulate the new perforations.

Mike L. Laue

2001-09-28T23:59:59.000Z

25

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

DOE Green Energy (OSTI)

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

Engelder, T.; Scholz, C.

1977-03-01T23:59:59.000Z

26

Commercialization of a high-performance continuous reforming catalyst  

Science Conference Proceedings (OSTI)

In 1971, the first CCR Platforming process was started up in the US on the Gulf Coast. Twenty-two years later, more than 108 continuous reforming units are operating worldwide. Another 50 CCR Platforming units are in various stages of design, construction, or start-up. Continuous catalytic reforming now represents more than 25% of the world's reforming capacity. Throughout these three decades, the UOP CCR Platforming technology continuously improved in terms of catalyst and process in response to changing industry requirements. Processing conditions in 1993 place tremendous demands on the catalyst in the reforming unit. This paper reviews the challenges and needs of the changing refining industry and the development of a new generation of CCR Platforming catalyst, R-132, and focuses on the first commercial operation of this high-activity, surface-stable catalyst. Case studies show how a refiner can improve margins by using the high activity, yield stability, longer life, and improved chloride retention benefits of this new R-132 Platforming catalyst.

Gilsdorf, N.L.; Doornbos, A.E.; Gevelinger, T.J. (UOP, Des Plaines, IL (United States)); Angelo, C.M.D. (Petrogal Refinaria de Sines (Portugal))

1993-01-01T23:59:59.000Z

27

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

SciTech Connect

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

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

1996-08-01T23:59:59.000Z

28

Correlation of microstructure and fracture toughness in three high-speed steel rolls  

SciTech Connect

The objective of this study is to clarify the fracture characteristics of high-speed steel (HSS) rolls in terms of microstructural factors such as matrix phase and primary carbide particles. Three HSS rolls with different chromium contents were fabricated by centrifugal casting, and the effect of the chromium addition was investigated through microstructural analysis, fracture-mechanism study, and toughness measurement. The hard and brittle primary carbides, as well as the eutectic carbides (ledeburites), were segregated in the intercellular regions and dominated overall properties. Observation of the fracture process revealed that these primary carbides cleaved first to form microcracks at low stress-intensity factor levels and that the microcracks then readily propagated along the intercellular networks. The addition of chromium to a certain level yielded microstructural modification, including the homogeneous distribution of primary carbides, thereby leading to enhancement of fracture toughness of the HSS rolls.

Lee, S.; Sohn, K.S.; Lee, C.G. [Pohang Univ. of Science and Technology (Korea, Republic of). Center for Advanced Aerospace Materials; Jung, B.I. [Kangwon Industries, Ltd., Pohang (Korea, Republic of). Roll Technology Dept.

1997-01-01T23:59:59.000Z

29

Continuous air Agglomeration Method for high Carbon fly ash Beneficiation  

DOE Patents (OSTI)

The carbon and mineral components of fly ash are effectively separated by a continuous air agglomeration method, resulting in a substantially carbon-free mineral stream and a highly concentrated carbon product. The method involves mixing the fly ash comprised of carbon and inorganic mineral matter with a liquid hydrocarbon to form a slurry, contacting the slurry with an aqueous solution, dispersing the hydrocarbon slurry into small droplets within the aqueous solution by mechanical mixing and/or aeration, concentrating the inorganic mineral matter in the aqueous solution, agglomerating the carbon and hydrocarbon in the form of droplets, collecting the droplets, separating the hydrocarbon from the concentrated carbon product, and recycling the hydrocarbon.

Gray, McMahan L.; Champagne, Kenneth J.; Finseth, Dennis H.

1998-09-29T23:59:59.000Z

30

Continuous air agglomeration method for high carbon fly ash beneficiation  

DOE Patents (OSTI)

The carbon and mineral components of fly ash are effectively separated by a continuous air agglomeration method, resulting in a substantially carboree mineral stream and a highly concentrated carbon product. The method involves mixing the fly ash comprised of carbon and inorganic mineral matter with a liquid hydrocarbon to form a slurry, contacting the slurry with an aqueous solution, dispersing the hydrocarbon slurry into small droplets within the aqueous solution by mechanical mixing and/or aeration, concentrating the inorganic mineral matter in the aqueous solution, agglomerating the carbon and hydrocarbon in the form of droplets, collecting the droplets, separating the hydrocarbon from the concentrated carbon product, and recycling the hydrocarbon.

Gray, McMahon L. (Pittsburgh, PA); Champagne, Kenneth J. (Monongahela, PA); Finseth, Dennis H. (Pittsburgh, PA)

2000-01-01T23:59:59.000Z

31

Trenches Under The Pipeline: The Educational Trajectories of Chicano Male Continuation High School Students  

E-Print Network (OSTI)

Trenches Under The Pipeline: The Educational Trajectories ofnavigate the educational pipeline, continuation high school

Malagon, Maria

2010-01-01T23:59:59.000Z

32

An accurate continuous calibration system for high voltage current transformer  

SciTech Connect

A continuous calibration system for high voltage current transformers is presented in this paper. The sensor of this system is based on a kind of electronic instrument current transformer, which is a clamp-shape air core coil. This system uses an optical fiber transmission system for its signal transmission and power supply. Finally the digital integrator and fourth-order convolution window algorithm as error calculation methods are realized by the virtual instrument with a personal computer. It is found that this system can calibrate a high voltage current transformer while energized, which means avoiding a long calibrating period in the power system and the loss of power metering expense. At the same time, it has a wide dynamic range and frequency band, and it can achieve a high accuracy measurement in a complex electromagnetic field environment. The experimental results and the on-site operation results presented in the last part of the paper, prove that it can reach the 0.05 accuracy class and is easy to operate on site.

Tong Yue; Li Binhong [College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, Hubei Province (China)

2011-02-15T23:59:59.000Z

33

Shear Fracture of Advanced High Strength Steels (AHSS)  

Science Conference Proceedings (OSTI)

D8: Study of Rack and Chord Assembly Formability for Jack-up Platforms ... Zone of Zr-Ti Microalloyed High-strength High-toughness Offshore Structural Steels.

34

High Throughput, Continuous, Mass Production of Photovoltaic Modules  

DOE Green Energy (OSTI)

AVA Solar has developed a very low cost solar photovoltaic (PV) manufacturing process and has demonstrated the significant economic and commercial potential of this technology. This I & I Category 3 project provided significant assistance toward accomplishing these milestones. The original goals of this project were to design, construct and test a production prototype system, fabricate PV modules and test the module performance. The original module manufacturing costs in the proposal were estimated at $2/Watt. The objectives of this project have been exceeded. An advanced processing line was designed, fabricated and installed. Using this automated, high throughput system, high efficiency devices and fully encapsulated modules were manufactured. AVA Solar has obtained 2 rounds of private equity funding, expand to 50 people and initiated the development of a large scale factory for 100+ megawatts of annual production. Modules will be manufactured at an industry leading cost which will enable AVA Solar's modules to produce power that is cost-competitive with traditional energy resources. With low manufacturing costs and the ability to scale manufacturing, AVA Solar has been contacted by some of the largest customers in the PV industry to negotiate long-term supply contracts. The current market for PV has continued to grow at 40%+ per year for nearly a decade and is projected to reach $40-$60 Billion by 2012. Currently, a crystalline silicon raw material supply shortage is limiting growth and raising costs. Our process does not use silicon, eliminating these limitations.

Kurt Barth

2008-02-06T23:59:59.000Z

35

Economic Recovery of Oil Trapped at Fan Margins Using High Angle Wells and Multiple Hydraulic Fractures  

Science Conference Proceedings (OSTI)

This project attempts to demonstrate the effectivensss of exploiting thin-layered, low energy deposits at the distal margin of a propagating turbinite complex through u se of hydraulically fractgured horizontal of high-angle wells. TGhe combinaton of a horizontal or high-angle weoo and hydraulic fracturing will allow greater pay exposure than can be achieved with conventional vertical wells while maintaining vertical communication between thin interbedded layers and the wellbore.

Mike L. Laue

1998-02-05T23:59:59.000Z

36

Investigation and modeling of the elastic-plastic fracture behavior of continuous woven fabric-reinforced ceramic composites  

SciTech Connect

The paper describes a study which attempted to extrapolate meaningful elastic-plastic fracture toughness data from flexure tests of a chemical vapor-infiltrated SiC/Nicalon fiber-reinforced ceramic matrix composite. Fibers in the fabricated composites were pre-coated with pyrolytic carbon to varying thicknesses. In the tests, crack length was not measured and the study employed an estimate procedure, previously used successfully for ductile metals, to derive J-R curve information. Results are presented in normalized load vs. normalized displacements and comparative J{sub Ic} behavior as a function of fiber precoating thickness.

Kahl, W.K. [Oak Ridge National Lab., TN (United States). Engineering Technology Div.

1997-03-01T23:59:59.000Z

37

Modelling and Simulation of Tensile Fracture in High Velocity Compacted Metal Powder  

Science Conference Proceedings (OSTI)

In cold uniaxial powder compaction, powder is formed into a desired shape with rigid tools and a die. After pressing, but before sintering, the compacted powder is called green body. A critical property in the metal powder pressing process is the mechanical properties of the green body. Beyond a green body free from defects, desired properties are high strength and uniform density. High velocity compaction (HVC) using a hydraulic operated hammer is a production method to form powder utilizing a shock wave. Pre-alloyed water atomised iron powder has been HVC-formed into circular discs with high densities. The diametral compression test also called the Brazilian disc test is an established method to measure tensile strength in low strength material like e.g. rock, concrete, polymers and ceramics. During the test a thin disc is compressed across the diameter to failure. The compression induces a tensile stress perpendicular to the compressed diameter. In this study the test have been used to study crack initiation and the tensile fracture process of HVC-formed metal powder discs with a relative density of 99%. A fictitious crack model controlled by a stress versus crack-width relationship is utilized to model green body cracking. Tensile strength is used as a failure condition and limits the stress in the fracture interface. The softening rate of the model is obtained from the corresponding rate of the dissipated energy. The deformation of the powder material is modelled with an elastic-plastic Cap model. The characteristics of the tensile fracture development of the central crack in a diametrically loaded specimen is numerically studied with a three dimensional finite element simulation. Results from the finite element simulation of the diametral compression test shows that it is possible to simulate fracturing of HVC-formed powder. Results from the simulation agree reasonably with experiments.

Jonsen, P.; Haeggblad, H.-A. [Division of Solid Mechanics, Department of Applied Physics and Mechanical Engineering, Luleaa University of Technology, 971 87 Luleaa (Sweden)

2007-05-17T23:59:59.000Z

38

Irradiation dose and temperature dependence of fracture toughness in high dose HT9 steel from the fuel duct of FFTF  

SciTech Connect

Static fracture toughness tests have been performed for high dose HT9 steel using miniature disk compact tension (DCT) specimens to expand the knowledge base for fast reactor core materials. The HT9 steel DCT specimens were from the ACO-3 duct of the Fast Flux Test Facility (FFTF), which achieved high doses in the range of 3 148 dpa at 378 504oC. The static fracture resistance (J-R) tests have been performed in a servohydraulic testing machine in vacuum at selected temperatures including room temperature, 200 C, and each irradiation temperature. Brittle fracture with a low toughness less than 50 MPa m occurred in room temperature tests when irradiation temperature was below 400 C, while ductile fracture with stable crack growth was observed in all tests at higher irradiation temperatures. No fracture toughness less than 100 MPa m was measured when the irradiation temperature was above 430 C. It was shown that the influence of irradiation temperature was dominant in fracture toughness while the irradiation dose has only limited influence over the dose range 3 148 dpa. A post upper-shelf behavior was observed for the non-irradiated and high temperature (>430 C) irradiation cases, which indicates that the ductile-brittle transition temperatures (DBTTs) in those conditions are lower than room temperature. A comparison with the collection of existing data confirmed the dominance of irradiation temperature in the fracture toughness of HT9 steels.

Byun, Thak Sang [ORNL; Toloczko, M [Pacific Northwest National Laboratory (PNNL); Maloy, S [Los Alamos National Laboratory (LANL)

2012-01-01T23:59:59.000Z

39

High level waste facilities -- Continuing operation or orderly shutdown  

SciTech Connect

Two options for Environmental Impact Statement No action alternatives describe operation of the radioactive liquid waste facilities at the Idaho Chemical Processing Plant at the Idaho National Engineering and Environmental Laboratory. The first alternative describes continued operation of all facilities as planned and budgeted through 2020. Institutional control for 100 years would follow shutdown of operational facilities. Alternatively, the facilities would be shut down in an orderly fashion without completing planned activities. The facilities and associated operations are described. Remaining sodium bearing liquid waste will be converted to solid calcine in the New Waste Calcining Facility (NWCF) or will be left in the waste tanks. The calcine solids will be stored in the existing Calcine Solids Storage Facilities (CSSF). Regulatory and cost impacts are discussed.

Decker, L.A.

1998-04-01T23:59:59.000Z

40

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

E-Print Network (OSTI)

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

Correa Castro, Juan

2011-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "highly fractured continuous" 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

High Power Superconducting Continuous Wave Linacs for Protons...  

Office of Science (SC) Website

(ANL) Developed in: Current Result of NP research: Spin-off of high power driver linac R&D for the FRIB project Application currently being supported by: DOE Office of Nuclear...

42

Geothermal fracture stimulation technology. Volume II. High-temperature proppant testing  

DOE Green Energy (OSTI)

Data were obtained from a newly built proppant tester, operated at actual geothermal temperatures. The short term test results show that most proppants are temperature sensitive, particularly at the higher closure stresses. Many materials have been tested using a standard short-term test, i.e., fracture-free sand, bauxite, and a resin-coated sand retained good permeability at the high fluid temperatures in brine over a range of closure stresses. The tests were designed to simulate normal closure stress ranges for geothermal wells which are estimated to be from 2000 to 6000 psi. Although the ultra high closure stresses in oil and gas wells need not be considered with present geothermal resources, there is a definite need for chemically inert proppants that will retain high permeability for long time periods in the high temperature formations.

Not Available

1980-07-01T23:59:59.000Z

43

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

E-Print Network (OSTI)

This thesis addresses the problem of removal of Naturally Occurring Radioactive Materials, NORM, and describes an effective alternative to the current treatment method for their removal. High-pen-meability fracturing, recently established in the petroleum industry, is the recommended technique. NORM are found throughout subterranean formations. Whenever fluids from petroleum or water reservoirs are produced NORM are present in varying quantities. NORM can only be sensed with radiation detectors. However, they have proven carcinogens, and the US Environmental Protection Agency has set a limit on the maximum contaminated level of any stream. Until now, the preferred method of treatment was to remove NORM from contaminated waters with specially designed filters, which in turn create a new problem. The same filters that are used to treat the water themselves become highly radioactive with a considerable disposal problem. In the petroleum industry, NORM become concentrated in the scale that is deposited inside the well or surface pipes. When scale is removed, it can be so radioactive that it can only be stored in toxic sites. Additionally, as water is produced along with oil, so are NORM. Until now, for the Gulf of Mexico at least, produced water has been released into the ocean, but the Environmental Protection Agency (EPA) is threatening to change this. In the North Sea the regulations are already stricter. There is then a compelling motivation to remove NORM before they are produced, and thus, eliminate the disposal problem. A high-permeability fracture design is presented which modifies existing petroleum practices by introducing within the proppant pack highly selective radionuclide sorbents. These sorbents, at calculated concentrations, can remove NORM readily for several years from typical flow rates containing typical NORM concentrations.

Demarchos, Andronikos Stavros

1998-01-01T23:59:59.000Z

44

Predicting Fracture Toughness of TRIP 800 using Phase Properties Characterized by In-Situ High Energy X-Ray Diffraction  

Science Conference Proceedings (OSTI)

TRansformation Induced Plasticity (TRIP) steel is a typical representative of 1st generation advanced high strength steel (AHSS) which exhibits a combination of high strength and excellent ductility due to its multiphase microstructure. In this paper, we study the crack propagation behavior and fracture resistance of a TRIP 800 steel using a microstructure-based finite element method with the various phase properties characterized by in-situ high energy Xray diffraction (HEXRD) technique. Uniaxial tensile tests on the notched TRIP 800 sheet specimens were also conducted, and the experimentally measured tensile properties and R-curves (Resistance curves) were used to calibrate the modeling parameters and to validate the overall modeling results. The comparison between the simulated and experimentally measured results suggests that the micromechanics based modeling procedure can well capture the overall complex crack propagation behaviors and the fracture resistance of TRIP steels. The methodology adopted here may be used to estimate the fracture resistance of various multiphase materials.

Soulami, Ayoub; Choi, Kyoo Sil; Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.; Ren, Yang; Wang, Yan-Dong

2010-05-01T23:59:59.000Z

45

Pressure oscillations caused by momentum on shut in of a high rate well in a fractured formation  

DOE Green Energy (OSTI)

Pressure transient testing techniques are an important part of reservoir and production testing procedures. These techniques are frequently used to determine practical information about underground reservoirs such as the permeability, porosity, liquid content, reservoir and liquid discontinuities and other related data. This information is valuable in helping to analyze, improve and forecast reservoir performance. This report is concerned with developing models for pressure transient well testing in high permeability, high flow rate, naturally fractured reservoirs. In the present work, a study was made of the effects of liquid inertia in the fractures and the wellbore on the pressure response obtained during a well test. The effects of turbulent flow and multi-phase flow effects such as gravitational segregation or anisotropic porous media effects were not considered. The scope of the study was limited to studying inertial effects on the pressure response of a fractured reservoir.

Bhatnagar, S.

1989-06-01T23:59:59.000Z

46

High Efficient Secret Key Distillation for Long Distance Continuous Variable Quantum Key Distribution  

E-Print Network (OSTI)

The continuous variable quantum key distribution is expected to provide high secret key rate without single photon source and detector, but the lack of the secure and effective key distillation method makes it unpractical. Here, we present a secure single-bit-reverse-reconciliation protocol combined with secret information concentration and post-selection, which can distill the secret key with high efficiency and low computational complexity. The simulation results show that this protocol can provide high secret key rate even when the transmission fiber is longer than 150km, which may make the continuous variable scheme to outvie the single photon one.

Yi-bo Zhao; Zheng-fu Han; Jin-jian Chen; You-zhen Gui; Guang-can Guo

2006-03-08T23:59:59.000Z

47

Non-darcy flow behavior mean high-flux injection wells in porous and fractured formations  

E-Print Network (OSTI)

Phase and Multiphase Non-Darcy Flow in Porous and FracturedFormulation A multiphase system in a porous or fracturedand multiphase non-Darcy flow in multidimensional porous and

Wu, Yu-Shu

2003-01-01T23:59:59.000Z

48

Economic recovery of oil trapped at fan margins using high angle wells and multiple hydraulic fractures. Quarterly report, July 1--September 30, 1997  

SciTech Connect

This project attempts to demonstrate the effectiveness of exploiting thin-layered, low-energy deposits at the distal margin of a prograding turbidite complex through the use of hydraulically fractured horizontal or high-angle wells. The combination of a horizontal or high-angle well and hydraulic fracturing will allow greater pay exposure than can be achieved with conventional vertical wells while maintaining vertical communication between thin interbedded layers and the wellbore. A high-angle well will be drilled in the fan-margin portion of a slope-basin clastic reservoir and will be completed with multiple hydraulic-fracture treatments. Geologic modeling, reservoir characterization, and fine-grid reservoir simulation will be used to select the well location and orientation. Design parameters for the hydraulic-fracture treatments will be determined, in part, by fracturing an existing test well. Fracture azimuth will be predicted by passive seismic monitoring of a fracture-stimulation treatment in the test well using logging tools in an offset well. The long radius, near horizontal well has been drilled. After pumping a remedial cement squeeze, all pay behind the 5 in. liner was perforated and stimulated. Once wellwork is complete for the existing perforations, a hydraulic fracture treatment will be pumped through a short interval of clustered perforations in the 7 in. liner. Following this frac, all pay behind the 7 in. liner will be perforated and completion operations will be final.

Laue, M.L.

1997-10-30T23:59:59.000Z

49

HYDRAULIC FRACTURING  

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

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

50

A CONTINUOUS HIGH POWER BEAM DUMP OF THE HOT-DOG-COOKER TYPE  

SciTech Connect

A beam dump with partially rotating water-cooled tube arrays is proposed and studied for the dump of continuous high power density unneutralized ion beams out of the neutral beam injectors. Analyses were made of both steady and transient heat transfer characteristics.

Yoshikawa, Kiyoshi

1980-03-01T23:59:59.000Z

51

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

SciTech Connect

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

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

1991-01-01T23:59:59.000Z

52

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.

53

TECHNICAL BASIS AND APPLICATION OF NEW RULES ON FRACTURE CONTROL OF HIGH PRESSURE HYDROGEN VESSEL IN ASME SECTION VIII, DIVISION 3 CODE  

DOE Green Energy (OSTI)

As a part of an ongoing activity to develop ASME Code rules for the hydrogen infrastructure, the ASME Boiler and Pressure Vessel Code Committee approved new fracture control rules for Section VIII, Division 3 vessels in 2006. These rules have been incorporated into new Article KD-10 in Division 3. The new rules require determining fatigue crack growth rate and fracture resistance properties of materials in high pressure hydrogen gas. Test methods have been specified to measure these fracture properties, which are required to be used in establishing the vessel fatigue life. An example has been given to demonstrate the application of these new rules.

Rawls, G

2007-04-30T23:59:59.000Z

54

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

Science Conference Proceedings (OSTI)

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

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

2004-11-01T23:59:59.000Z

55

Fracture characterization of multilayered reservoirs  

Science Conference Proceedings (OSTI)

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

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

1986-01-01T23:59:59.000Z

56

TEMPORAL VARIATIONS OF FRACTURE DIRECTIONS AND FRACTURE DENSITIES IN THE  

Open Energy Info (EERE)

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

57

Structural Settings Of Hydrothermal Outflow- Fracture Permeability...  

Open Energy Info (EERE)

elevated stress termed breakdown regions. Here, stress concentrations cause active fracturing and continual re-opening of fluid-flow conduits, permitting long-lived hydrothermal...

58

Naturally fractured tight gas reservoir detection optimization  

SciTech Connect

Research continued on methods to detect naturally fractured tight gas reservoirs. This report discusses 3D-3C seismic acquisition and 3D P-wave alternate processing.

NONE

1995-12-31T23:59:59.000Z

59

High velocity continuous-flow reactor for the production of solar grade silicon. Second quarterly report  

DOE Green Energy (OSTI)

The objective is to determine the feasibility of a high volume-high velocity continuous reduction reactor as an economical means for producing solar grade polycrystalline silicon. Preheated streams of hydrogen and bromosilanes are used as feed to the reduction reactor. Nucleation and deposition sites are provided by the additional feed of preheated silicon particles to the reactor. The effort has been directed at studying the chemistry taking place in the reactor, determining the factors which influence its course, and making necessary reactor modifications as dictated by observed results. The initial reactor design has been extensively changed. Energy losses due to gas expansion in the nozzle/mixer section of the reactor dictated these design changes. A ''Tee'' configuration, in which the two preheated gas streams are merged at right angles without any expansion, has replaced the nozzle/mixer. Results of the hydrogen reduction of tetrabromosilane with and without the use of silicon deposition substrate particles are analyzed.

Woerner, L.

1978-03-01T23:59:59.000Z

60

Low-temperature conversion of high-moisture biomass: Continuous reactor system results  

DOE Green Energy (OSTI)

Pacific Northwest Laboratory (PNL) is developing a low-temperature, catalytic process for converting high-moisture biomass feedstocks and other wet organic substances to useful gaseous fuels. This system, in which thermocatalytic conversion takes place in an aqueous environment, was designed to overcome the problems usually encountered with high-water-content feedstocks. The process uses a reduced nickel catalyst at temperatures as low as 350{degree}C and pressures ranging from 2000 to 4000 psig -- conditions favoring the formation of gas consisting mostly of methane. The results of numerous batch tests showed that the system could convert feedstocks not readily converted by conventional methods. Fifteen tests were conducted in a continuous reactor system to further evaluate the effectiveness of the process for high-moisture biomass gasification and to obtain conversion rate data needed for process scaleup. During the tests, the complex gasification reactions were evaluated by several analytical methods. The results of these tests show that the heating value of the gas ranged from 400 to 500 Btu/scf, and if the carbon dioxide is removed, the product gas is pipeline quality. Conversion of the feedstocks was high. Engineering analysis indicates that, based on these results, a tubular reactor can be designed that should convert greater than 99% of the carbon fed as high-moisture biomass to a gaseous product in a reaction time of less than 11 min.

Elliott, D.C.; Sealock, L.J. Jr.; Butner, R.S.; Baker, E.G.; Neuenschwander, G.G.

1989-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "highly fractured continuous" 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

Three-Apogee 16-h Highly Elliptical Orbit as Optimal Choice for Continuous Meteorological Imaging of Polar Regions  

Science Conference Proceedings (OSTI)

A highly elliptical orbit (HEO) with a 16-h period is proposed for continuous meteorological imaging of polar regions from a two-satellite constellation. This orbit is characterized by three apogees (TAP) separated by 120°. The two satellites are ...

Alexander P. Trishchenko; Louis Garand; Larisa D. Trichtchenko

2011-11-01T23:59:59.000Z

62

Relative permeability through fractures  

DOE Green Energy (OSTI)

The mechanism of two-phase flow through fractures is of importance in understanding many geologic processes. Currently, two-phase flow through fractures is still poorly understood. In this study, nitrogen-water experiments were done on both smooth and rough parallel plates to determine the governing flow mechanism for fractures and the appropriate methodology for data analysis. The experiments were done using a glass plate to allow visualization of flow. Digital video recording allowed instantaneous measurement of pressure, flow rate and saturation. Saturation was computed using image analysis techniques. The experiments showed that gas and liquid phases flow through fractures in nonuniform separate channels. The localized channels change with time as each phase path undergoes continues breaking and reforming due to invasion of the other phase. The stability of the phase paths is dependent on liquid and gas flow rate ratio. This mechanism holds true for over a range of saturation for both smooth and rough fractures. In imbibition for rough-walled fractures, another mechanism similar to wave-like flow in pipes was also observed. The data from the experiments were analyzed using Darcy's law and using the concept of friction factor and equivalent Reynold's number for two-phase flow. For both smooth- and rough-walled fractures a clear relationship between relative permeability and saturation was seen. The calculated relative permeability curves follow Corey-type behavior and can be modeled using Honarpour expressions. The sum of the relative permeabilities is not equal one, indicating phase interference. The equivalent homogeneous single-phase approach did not give satisfactory representation of flow through fractures. The graphs of experimentally derived friction factor with the modified Reynolds number do not reveal a distinctive linear relationship.

Diomampo, Gracel, P.

2001-08-01T23:59:59.000Z

63

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 smaller stimulated pore volume than what would be expected from microseismic evidence and reports of fracturing fluids reaching distant wells. In addition, claims that hydraulic fracturing may open or reopen a network of natural fractures is of particular interest. This study examines hydraulic fracturing of shale gas formations with specific interest in fracture geometry. Several field cases are analyzed using microseismic analysis as well as net pressure analysis of the fracture treatment. Fracture half lengths implied by microseismic events for some of the stages are several thousand feet in length. The resulting dimensions from microseismic analysis are used for calibration of the treatment model. The fracture profile showing created and propped fracture geometry illustrates that it is not possible to reach the full fracture geometry implied by microseismic given the finite amount of fluid and proppant that was pumped. The model does show however that the created geometry appears to be much larger than half the well spacing. From a productivity standpoint, the fracture will not drain a volume more than that contained in half of the well spacing. This suggests that for the case of closely spaced wells, the treatment size should be reduced to a maximum of half the well spacing. This study will provide a framework for understanding hydraulic fracture treatments in shale formations. In addition, the results from this study can be used to optimize hydraulic fracture treatment design. Excessively large treatments may represent a less than optimal approach for developing these resources.

Ahmed, Ibraheem 1987-

2012-12-01T23:59:59.000Z

64

Hydraulic Fracturing (Vermont)  

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

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

65

ALTERNATIVE EDUCATION IN CONTINUATION HIGH SCHOOLS: MEETING THE NEEDS OF OVER-AGED UNDER-CREDITED YOUTH  

E-Print Network (OSTI)

California school districts operate 519 continuation high schools that enrolled over 115,000 students over the course of the 2006-07 school year. 1 Originally designed to provide a flexible schedule for working students to continuing their schooling, the modern continuation high school now serves a diverse population of students. The single common denominator is that most continuation students have reached the 9 th or 10 th grades lacking sufficient academic credits to remain on track to graduate with their age cohort. Since 1965, state law has mandated that all school districts enrolling over 100 12 th grade students make available a continuation program or school to provide an alternative route to the high school diploma for youth vulnerable to academic or behavioral failure. The law, unique to California, contemplates accelerated credit accrual strategies and more intensive services “including, but not limited to, independent study, regional occupation programs, work study, career counseling, and job placement services ” so that students might have a renewed opportunity to “complete the required academic courses of instruction to graduate from high school. ” 2 This legislative design thus makes clear that continuation schools constitute the state’s primary drop-out

Jorge Ruiz De Velasco

2008-01-01T23:59:59.000Z

66

The High Cycle Fatigue and Final Fracture Behavior of Alloy Steel ...  

Science Conference Proceedings (OSTI)

Energy Based Fatigue Life Prediction Models and Methods for Combined Low Cycle and High Cycle Fatigue · Fatigue Behavior of AM60B Subjected to Variable  ...

67

Application of DIC to the Study of Damage & Fracture in High ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Cracking is the dominant mechanical failure mechanism in high explosives (HE) and could affect safety and performance of weapon and ...

68

Characterization of High Temperature Fracture Strength of CVD-SiC ...  

Science Conference Proceedings (OSTI)

CASL: The Consortium for Advanced Simulation of Light Water Reactors: A U.S. ... Strategies for Studying High Dose Irradiation Effects in Reactor Components.

69

FRACTURING FLUID CHARACTERIZATION FACILITY  

SciTech Connect

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

70

Structural Settings Of Hydrothermal Outflow- Fracture Permeability  

Open Energy Info (EERE)

Settings Of Hydrothermal Outflow- Fracture Permeability Settings Of Hydrothermal Outflow- Fracture Permeability Maintained By Fault Propagation And Interaction Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Structural Settings Of Hydrothermal Outflow- Fracture Permeability Maintained By Fault Propagation And Interaction Details Activities (1) Areas (1) Regions (0) Abstract: Hydrothermal outflow occurs most commonly at the terminations of individual faults and where multiple faults interact. These areas of fault propagation and interaction are sites of elevated stress termed breakdown regions. Here, stress concentrations cause active fracturing and continual re-opening of fluid-flow conduits, permitting long-lived hydrothermal flow despite potential clogging of fractures due to mineral precipitation. As

71

Continuous high-solids anaerobic co-digestion of organic solid wastes under mesophilic conditions  

SciTech Connect

Highlights: > High-solids (dry) anaerobic digestion is attracting a lot of attention these days. > One reactor was fed with food waste (FW) and paper waste. > Maximum biogas production rate of 5.0 m{sup 3}/m{sup 3}/d was achieved at HRT 40 d and 40% TS. > The other reactor was fed with FW and livestock waste (LW). > Until a 40% LW content increase, the reactor exhibited a stable performance. - Abstract: With increasing concerns over the limited capacity of landfills, conservation of resources, and reduction of CO{sub 2} emissions, high-solids (dry) anaerobic digestion of organic solid waste (OSW) is attracting a great deal of attention these days. In the present work, two dry anaerobic co-digestion systems fed with different mixtures of OSW were continuously operated under mesophilic conditions. Dewatered sludge cake was used as a main seeding source. In reactor (I), which was fed with food waste (FW) and paper waste (PW), hydraulic retention time (HRT) and solid content were controlled to find the maximum treatability. At a fixed solid content of 30% total solids (TS), stable performance was maintained up to an HRT decrease to 40 d. However, the stable performance was not sustained at 30 d HRT, and hence, HRT was increased to 40 d again. In further operation, instead of decreasing HRT, solid content was increased to 40% TS, which was found to be a better option to increase the treatability. The biogas production rate (BPR), CH{sub 4} production yield (MPY) and VS reduction achieved in this condition were 5.0 m{sup 3}/m{sup 3}/d, 0.25 m{sup 3} CH{sub 4}/g COD{sub added}, and 80%, respectively. Reactor (II) was fed with FW and livestock waste (LW), and LW content was increased during the operation. Until a 40% LW content increase, reactor (II) exhibited a stable performance. A BPR of 1.7 m{sup 3}/m{sup 3}/d, MPY of 0.26 m{sup 3} CH{sub 4}/g COD{sub added}, and VS reduction of 72% was achieved at 40% LW content. However, when the LW content was increased to 60%, there was a significant performance drop, which was attributed to free ammonia inhibition. The performances in these two reactors were comparable to the ones achieved in the conventional wet digestion and thermophilic dry digestion processes.

Kim, Dong-Hoon [Wastes Energy Research Center, Korea Institute of Energy Research, 102, Gajeong-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Oh, Sae-Eun, E-mail: saeun@hanbat.ac.kr [Department of Environmental Engineering, Hanbat National University, San 16-1, Duckmyoung-dong, Yuseong-gu, Daejeon (Korea, Republic of)

2011-09-15T23:59:59.000Z

72

High temperature fracture and fatigue of ceramics. Final technical report, August 14, 1989--August 14, 1997  

Science Conference Proceedings (OSTI)

This program has supported basic research into the mechanisms and mechanics of failure of ceramic matrix composites at high temperature and under cyclic loads. Specialist experiments have been developed to assess mechanisms by in situ observations of specimens under load at temperature. Extensive models have been formulated based on observed mechanisms. A central theme has been the theory of bridged cracks, which appear as a universal mechanism in CMC failure. Fundamentals of bridged cracks have been elucidated, including length scales and important asymptotic limits. Both experiments and models have studied rate dependent problems, for example, cracking at high temperature in the presence of fiber creep in composites.

Cox, B.

1998-06-01T23:59:59.000Z

73

Fracture Toughness Characterization of 304L and 316L and Alloy 718 After Irradiation in High-Energy, Mixed Proton/Neutron Spectrum  

DOE Green Energy (OSTI)

This paper describes the fracture toughness characterization of annealed 304L and 316L stainless steels and precipitation hardened Alloy 718, performed at the Oak Ridge National Laboratory as a part of the experimental design and development for the Accelerator Production of Tritium (APT) target/blanket system. Materials were irradiated at 25 to 200 C by high-energy protons and neutrons from an 800-MeV, 1-mA proton beam at the Los Alamos Neutron Science Center (LANSCE). The proton flux produced in LANSCE is nearly prototypic of anticipated conditions for significant portions of the APT target/blanket system. The objective of this testing program was to determine the change in crack-extension resistance of candidate APT materials from irradiation at prototypic APT temperatures and proton and neutron fluxes. J-integral-resistance (J-R) curve toughness tests were conducted in general accordance with the American Society for Testing and Materials Standard Test Method for Measurement of Fracture Toughness, E 1820-99, with a computer-controlled test and data acquisition system. J-R curves were obtained from subsize disk-shaped compact tension specimens (12.5 mm in diameter) with thicknesses of 4 mm or 2 mm. Irradiation up to 12 dpa significantly reduced the fracture toughness of these materials. Alloy 718 had the lowest fracture toughness in both the unirradiated and irradiated conditions. All irradiated specimens of Alloy 718 failed by sudden unstable crack extension regardless of dose or test temperature. Type 304L and 316L stainless steels had a high level of fracture toughness in the unirradiated condition and exhibited reduction in fracture toughness to saturation levels of 65 to 100 MPa{radical}m. The present reduction in fracture toughness is similar to changes reported from fission reactor studies. However, the currently observed losses in toughness appear to saturate at doses slightly lower than the dose required for saturation in reactor-irradiated steels. This difference might be attributed to the increased helium and hydrogen production associated with irradiation in the high-energy, mixed proton/neutron spectrum.

Sokolov, M.A.

2001-03-16T23:59:59.000Z

74

Effect of high temperature hydrogenation on the fracture strength of a sintered alpha silicon carbide  

DOE Green Energy (OSTI)

The effect of high temperature hydrogenation on the strength of a pressureless sintered alpha silicon carbide was studied as a function of time. Samples were soaked in argon or a hydrogen-argon mixture (40:60, mole %) at 1400/sup 0/C for times of up to 50 hours. The samples were then broken in four point flexure at room temperature. It was found that the hydrogen attacked the material at grain boundaries, leaving loose SiC grains on the surface. Fifty hours in a hydrogenous atmosphere at 1400/sup 0/C caused an average 26% strength decrease. Surface degradation was evaluated using optical and scanning electron microscopy.

Jero, P.D.

1985-01-01T23:59:59.000Z

75

High-level networking with mobile code and first order AND-continuations  

Science Conference Proceedings (OSTI)

We describe a scheme for moving living code between a set of distributed processes coordinated with unification based Linda operations, and its application to building a comprehensive Logic programming based Internet programming framework. Mobile ... Keywords: Internet programming, Linda coordination, blackboard-based logic programming, code migration, dynamic recompilation, first order continuations, mobile agents, mobile computations, networking, remote execution

Paul Tarau; Veronica Dahl

2001-05-01T23:59:59.000Z

76

HIGH-PRESSURE AIR INJECTION: APPLICATION IN A FRACTURED AND KARSTED DOLOMITE RESERVOIR  

SciTech Connect

The Bureau of Economic Geology and Goldrus Producing Company have assembled a multidisciplinary team of geoscientists and engineers to evaluate the applicability of high-pressure air injection (HPAI) in revitalizing a nearly abandoned carbonate reservoir in the Permian Basin of West Texas. The characterization phase of the project is utilizing geoscientists and petroleum engineers from the Bureau of Economic Geology and the Department of Petroleum Engineering (both at The University of Texas at Austin) to define the controls on fluid flow in the reservoir as a basis for developing a reservoir model. This model will be used to define a field deployment plan that Goldrus, a small independent oil company, will implement by drilling both vertical and horizontal wells during the demonstration phase of the project. Additional reservoir data are being gathered during the demonstration phase to improve the accuracy of the reservoir model. The results of the demonstration will being closely monitored to provide a basis for improving the design of the HPAI field deployment plan. The results of the reservoir characterization field demonstration and monitoring program will be documented and widely disseminated to facilitate adoption of this technology by oil operators in the Permian Basin and elsewhere in the U.S.

Robert Loucks; Steve Ruppel; Julia Gale; Jon Holder; Jon Olsen; Deanna Combs; Dhiraj Dembla; Leonel Gomez

2003-12-10T23:59:59.000Z

77

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

78

Meshless animation of fracturing solids  

Science Conference Proceedings (OSTI)

We present a new meshless animation framework for elastic and plastic materials that fracture. Central to our method is a highly dynamic surface and volume sampling method that supports arbitrary crack initiation, propagation, and termination, while ... Keywords: elasticity, fracture, meshless methods, physics-based animation, plasticity

Mark Pauly; Richard Keiser; Bart Adams; Philip Dutré; Markus Gross; Leonidas J. Guibas

2005-07-01T23:59:59.000Z

79

REVIVING ABANDONED RESERVOIRS WITH HIGH-PRESSURE AIR INJECTION: APPLICATION IN A FRACTURED AND KARSTED DOLOMITE RESERVOIR  

SciTech Connect

The field operator, Goldrus Producing Company, has been unable to secure funding needed to continue the field demonstration phase of the project. Accordingly, we have temporarily halted all project activities until necessary funding is obtained. Goldrus felt confident that funds could be acquired by third quarter 2005 at which time it would have been necessary to request a project extension to complete the originally designed study. A project extension was granted but it appears Goldrus will have difficulty securing funds. We Bureau of Economic Geology are investigating a new approach on how to fulfill our initial objectives of promoting high-pressure air injection of Ellenburger reservoirs.

Robert Loucks; Stephen C. Ruppel

2006-02-01T23:59:59.000Z

80

Downhole tool sniffs out fractures  

SciTech Connect

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

Not Available

1987-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "highly fractured continuous" 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
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81

Synthetic benchmark for modeling flow in 3D fractured media  

Science Conference Proceedings (OSTI)

Intensity and localization of flows in fractured media have promoted the development of a large range of different modeling approaches including Discrete Fracture Networks, pipe networks and equivalent continuous media. While benchmarked usually within ... Keywords: Benchmark, Fractured media, Single-phase flow, Stochastic model

Jean-Raynald De Dreuzy; GéRaldine Pichot; Baptiste Poirriez; Jocelyne Erhel

2013-01-01T23:59:59.000Z

82

Use of TOUGHREACT to Simulate Effects of Fluid Chemistry onInjectivity in Fractured Geothermal Reservoirs with High Ionic StrengthFluids  

SciTech Connect

Recent studies suggest that mineral dissolution/precipitation and clay swelling effects could have a major impact on the performance of hot dry rock (HDR) and hot fractured rock (HFR) reservoirs. A major concern is achieving and maintaining adequate injectivity, while avoiding the development of preferential short-circuiting flow paths. A Pitzer ionic interaction model has been introduced into the publicly available TOUGHREACT code for solving non-isothermal multi-phase reactive geochemical transport problems under conditions of high ionic strength, expected in typical HDR and HFR systems. To explore chemically-induced effects of fluid circulation in these systems, we examine ways in which the chemical composition of reinjected waters can be modified to improve reservoir performance. We performed a number of coupled thermo-hydrologic-chemical simulations in which the fractured medium was represented by a one-dimensional MINC model (multiple interacting continua). Results obtained with the Pitzer activity coefficient model were compared with those using an extended Debye-Hueckel equation. Our simulations show that non-ideal activity effects can be significant even at modest ionic strength, and can have major impacts on permeability evolution in injection-production systems. Alteration of injection water chemistry, for example by dilution with fresh water, can greatly alter precipitation and dissolution effects, and can offer a powerful tool for operating hot dry rock and hot fractured rock reservoirs in a sustainable manner.

Xu, Tianfu; Zhang, Guoxiang; Pruess, Karsten

2005-02-09T23:59:59.000Z

83

Corporation Commission Hydraulic FracturingHydraulic Fracturing  

E-Print Network (OSTI)

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

Peterson, Blake R.

84

Reviving Abandoned Reservoirs with High-Pressure Air Injection: Application in a Fractured and Karsted Dolomite Reservoir  

Science Conference Proceedings (OSTI)

Despite declining production rates, existing reservoirs in the United States contain vast volumes of remaining oil that is not being effectively recovered. This oil resource constitutes a huge target for the development and application of modern, cost-effective technologies for producing oil. Chief among the barriers to the recovery of this oil are the high costs of designing and implementing conventional advanced recovery technologies in these mature, in many cases pressure-depleted, reservoirs. An additional, increasingly significant barrier is the lack of vital technical expertise necessary for the application of these technologies. This lack of expertise is especially notable among the small operators and independents that operate many of these mature, yet oil-rich, reservoirs. We addressed these barriers to more effective oil recovery by developing, testing, applying, and documenting an innovative technology that can be used by even the smallest operator to significantly increase the flow of oil from mature U.S. reservoirs. The Bureau of Economic Geology and Goldrus Producing Company assembled a multidisciplinary team of geoscientists and engineers to evaluate the applicability of high-pressure air injection (HPAI) in revitalizing a nearly abandoned carbonate reservoir in the Permian Basin of West Texas. The Permian Basin, the largest oil-bearing basin in North America, contains more than 70 billion barrels of remaining oil in place and is an ideal venue to validate this technology. We have demonstrated the potential of HPAI for oil-recovery improvement in preliminary laboratory tests and a reservoir pilot project. To more completely test the technology, this project emphasized detailed characterization of reservoir properties, which were integrated to access the effectiveness and economics of HPAI. The characterization phase of the project utilized geoscientists and petroleum engineers from the Bureau of Economic Geology and the Department of Petroleum Engineering (both at The University of Texas at Austin) to define the controls on fluid flow in the reservoir as a basis for developing a reservoir model. The successful development of HPAI technology has tremendous potential for increasing the flow of oil from deep carbonate reservoirs in the Permian Basin, a target resource that can be conservatively estimated at more than 1.5 billion barrels. Successful implementation in the field chosen for demonstration, for example, could result in the recovery of more than 34 million barrels of oil that will not otherwise be produced. Geological and petrophysical analysis of available data at Barnhart field reveals the following important observations: (1) the Barnhart Ellenburger reservoir is similar to most other Ellenburger reservoirs in terms of depositional facies, diagenesis, and petrophysical attributes; (2) the reservoir is characterized by low to moderate matrix porosity much like most other Ellenburger reservoirs in the Permian Basin; (3) karst processes (cave formation, infill, and collapse) have substantially altered stratigraphic architecture and reservoir properties; (4) porosity and permeability increase with depth and may be associated with the degree of karst-related diagenesis; (5) tectonic fractures overprint the reservoir, improving overall connectivity; (6) oil-saturation profiles show that the oil-water contact (OWC) is as much as 125 ft lower than previous estimations; (7) production history and trends suggest that this reservoir is very similar to other solution-gas-drive reservoirs in the Permian Basin; and (8) reservoir simulation study showed that the Barnhart reservoir is a good candidate for HPAI and that application of horizontal-well technology can improve ultimate resource recovery from the reservoir.

Robert Loucks; Stephen C. Ruppel; Dembla Dhiraj; Julia Gale; Jon Holder; Jeff Kane; Jon Olson; John A. Jackson; Katherine G. Jackson

2006-09-30T23:59:59.000Z

85

Fracture characterization study  

DOE Green Energy (OSTI)

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

Kehrman, R.F.

1978-04-01T23:59:59.000Z

86

REVIVING ABANDONED RESERVOIRS WITH HIGH-PRESSURE AIR INJECTION: APPLICATION IN A FRACTURED AND KARSTED DOLOMITE RESERVOIR  

SciTech Connect

The Bureau of Economic Geology (BEG) and Goldrus Producing Company have assembled a multidisciplinary team of geoscientists and engineers to evaluate the applicability of high-pressure air injection (HPAI) in revitalizing a nearly abandoned carbonate reservoir in the Permian Basin of West Texas. The characterization phase of the project is utilizing geoscientists and petroleum engineers from the Bureau of Economic Geology (BEG) and the Department of Petroleum and Geosystems Engineering (both at The University of Texas at Austin) to define the controls on fluid flow in the reservoir as a basis for developing a reservoir model. This model will be used to define a field deployment plan that Goldrus, a small independent oil company, will implement by drilling both vertical and horizontal wells during the demonstration phase of the project. Additional reservoir data were to be generated during the demonstration phase to improve the accuracy of the reservoir model. The demonstration phase has been delayed by Goldrus because of funding problems. Since the first of the year, Goldrus has been active in searching for partners to help finance the project. To this end it has commissioned several small consulting studies to technically support its effort to secure a partner. After financial support is obtained, the demonstration phase of the project will proceed. Since just after the beginning of the year, BEG has curtailed project activities and spending of DOE funds except for the continued support of one engineering student. This student has now completed his work and has written a thesis describing his research (titled ''Stimulating enhanced oil recovery (EOR) by high-pressure air injection (HPAI) in west Texas light oil reservoir''). We plan to recommence our work on the project as soon as the operator obtains necessary funding to carry out the demonstration phase of the project. In order to complete all activities specified in the proposal, it will be necessary to request an extension of the project from the originally defined completion date. We are confident that Goldrus will obtain the necessary funding to continue and that we can complete the project if an extension is granted. We strongly believe that the results of this study will provide the impetus for a new approach to enhanced oil recovery in the Permian Basin and elsewhere in the United States.

Robert Loucks; Steve Ruppel; Julia Gale; Jon Holder; Jon Olson; Deanna Combs; Dhiraj Dembla

2004-06-01T23:59:59.000Z

87

Automatic fracture density update using smart well data and artificial neural networks  

Science Conference Proceedings (OSTI)

This paper presents a new methodology to continuously update and improve fracture network models. We begin with a hypothetical model whose fracture network parameters and geological information are known. After generating the ''exact'' fracture network ... Keywords: ANN, Fracture networks, Production data, Smart wells, Static data, Static model

A. Al-Anazi; T. Babadagli

2010-03-01T23:59:59.000Z

88

REVIVING ABANDONED RESERVOIRS WITH HIGH-PRESSURE AIR INJECTION: APPLICATION IN A FRACTURED AND KARSTED DOLOMITE RESERVOIR  

SciTech Connect

The Bureau of Economic Geology (BEG) and Goldrus Producing Company have assembled a multidisciplinary team of geoscientists and engineers to evaluate the applicability of high-pressure air injection (HPAI) in revitalizing a nearly abandoned carbonate reservoir in the Permian Basin of West Texas. The characterization phase of the project is utilizing geoscientists and petroleum engineers from the Bureau of Economic Geology (BEG) and the Department of Petroleum and Geosystems Engineering (both at The University of Texas at Austin) to define the controls on fluid flow in the reservoir as a basis for developing a reservoir model. This model will be used to define a field deployment plan that Goldrus, a small independent oil company, will implement by drilling both vertical and horizontal wells during the demonstration phase of the project. Additional reservoir data were to be generated during the demonstration phase to improve the accuracy of the reservoir model. The demonstration phase has been delayed by Goldrus because of funding problems. Since the first of the year, Goldrus has been active in searching for partners to help finance the project. After financial support is obtained, the demonstration phase of the project will proceed. Since just after the beginning of the year, BEG has curtailed project activities and spending of DOE funds except for the continued support of one engineering student. This student has now completed his work and his thesis was reported on in the last semi-annual report. We plan to recommence our work on the project as soon as the operator obtains necessary funding to carry out the demonstration phase of the project. In order to complete all activities specified in the proposal, we requested and received an extension of the project to September 30, 2005. We are confident that Goldrus will obtain the necessary funding to continue and that we can complete the project by the end of the extension data. We strongly believe that the results of this study will provide the impetus for a new approach to enhanced oil recovery in the Permian Basin and elsewhere in the United States.

Robert Loucks; Steve Ruppel; Julia Gale; Jon Holder; Jon Olson

2005-01-01T23:59:59.000Z

89

Linear Elastic Fracture Mechanics  

Science Conference Proceedings (OSTI)

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

90

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

E-Print Network (OSTI)

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

Marpaung, Fivman

2007-12-01T23:59:59.000Z

91

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

E-Print Network (OSTI)

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

Marpaung, Fivman

2007-12-01T23:59:59.000Z

92

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

Science Conference Proceedings (OSTI)

This report summarizes the work carried out during the period of September 29, 2000 to September 28, 2001 under DOE Research Contract No. DE-FC26-00BC15308. Our goal is to establish an integrated methodology of fractured reservoir characterization and show how that can be incorporated into fluid flow simulation. We have made progress in the characterization of mineral infilling of natural fractures. The main advancement in this regard was to recognize the strong interplay between diagenetic and mechanical processes. We accomplished several firsts in documenting and quantifying these processes, including documenting the range of emergent threshold in several formations and quantifying the internal structures of crack-seal bridges in fractures. These results will be the basis for an appreciation of fracture opening and filling rates that go well beyond our original goals. Looking at geochemical modeling of fracture infilling, our theoretical analysis addressed the problem of calcite precipitation in a fracture. We have built a model for the deposition of calcite within a fracture. The diagenetic processes of dissolution and partial cementation are key controls on the creation and distribution of natural fractures within hydrocarbon reservoirs. Even with extensive data collection, fracture permeability still creates uncertainty in reservoir description and the prediction of well performance. Data on the timing and stages of diagenetic events can provide explanation as to why, when and where natural fractures will be open and permeable. We have been pursuing the fracture mechanics testing of a wide range of rocks, particularly sandstone using a key rock property test that has hitherto not been widely applied to sedimentary rocks. A major accomplishment in this first year has been to identify sample suites available in the core repository at the University of Texas that represent a wide range of diagenetic alteration and to begin to test these samples. The basis for the fluid flow simulations to be carried out in this part of the project is the adequate spatial characterization of fracture networks. Our initial focus has been on the tendency of fracture sets to cluster into highly fracture zones that are often widely separated. Our preliminary modeling work shows the extent of this clustering to be controlled by the subcritical fracture index of the material. With continued progress, we move toward an integrated fracture characterization methodology that will ultimately be applied through detailed reservoir simulation.

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

2003-04-01T23:59:59.000Z

93

Domain Decomposition for Flow in Porous Media with Fractures  

E-Print Network (OSTI)

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

Clarisse Alboin; Jerome Jaffre; Jean Roberts; Christophe Serres

1999-01-01T23:59:59.000Z

94

A hierarchical fracture model for the iterative multiscale finite volume method  

Science Conference Proceedings (OSTI)

An iterative multiscale finite volume (i-MSFV) method is devised for the simulation of multiphase flow in fractured porous media in the context of a hierarchical fracture modeling framework. Motivated by the small pressure change inside highly conductive ... Keywords: Fractured porous media, Hierarchical fractured modeling, Iterative multiscale finite volume, Iterative multiscale methods, Multiscale finite volume, Multiscale fracture modeling, Multiscale methods

Hadi Hajibeygi; Dimitris Karvounis; Patrick Jenny

2011-10-01T23:59:59.000Z

95

Hydrogen-Assisted Fracture: Materials Testing and Variables Governing Fracture  

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

Hydrogen-Assisted Fracture: Materials Hydrogen-Assisted Fracture: Materials Testing and Variables Governing Fracture Brian Somerday, Chris San Marchi, and Dorian Balch Sandia National Laboratories Livermore, CA Hydrogen Pipeline Working Group Workshop Augusta, GA August 30-31, 2005 SNL has 40+ years experience with effects of high-pressure hydrogen gas on materials * Design and maintenance of welded stainless steel pressure vessels for containment of high-pressure H 2 isotopes - Extensive testing of stainless steels exposed to high-pressure H 2 gas * Six-year program in 1970s focused on feasibility of using natural gas pipeline network for H 2 gas - Materials testing in high-pressure H 2 gas using laboratory specimens and model pipeline - Examined fusion zone and heat affected zones of welds * Active SNL staff have authored 70+ papers and organized 6

96

Imaging Hydraulic Fractures: Source Location Uncertainty Analysis At The UPRC Carthage Test Site  

E-Print Network (OSTI)

Hydraulic fracturing is a useful tool for enhancing gas and oil production. High-resolution seismic imaging of the fracture geometry and fracture growth process is the key in determining optimal spacing and location of ...

Li, Yingping

1996-01-01T23:59:59.000Z

97

Interactive fracture design model  

DOE Green Energy (OSTI)

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

Not Available

1980-05-01T23:59:59.000Z

98

Power mixture and green body for producing silicon nitride base articles of high fracture toughness and strength  

DOE Patents (OSTI)

A powder mixture and a green body for producing a silicon nitride-based article of improved fracture toughness and strength are disclosed. The powder mixture includes (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 [mu]m and a surface area of about 8-12m[sup 2]g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 [mu]m and a surface area of about 2-4 m[sup 2]/g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. The green body is formed from the powder mixture, an effective amount of a suitable oxide densification aid, and an effective amount of a suitable organic binder. No Drawings

Huckabee, M.L.; Buljan, S.T.; Neil, J.T.

1991-09-17T23:59:59.000Z

99

Power mixture and green body for producing silicon nitride base & articles of high fracture toughness and strength  

DOE Patents (OSTI)

A powder mixture and a green body for producing a silicon nitride-based article of improved fracture toughness and strength. The powder mixture includes 9a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon mitride powder of an average particle size of about 0.2 .mu.m and a surface area of about 8-12m.sup.2 g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 .mu.m and a surface area of about 2-4 m.sup.2 /g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified articel an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. The green body is formed from the powder mixture, an effective amount of a suitable oxide densification aid, and an effective amount of a suitable organic binder.

Huckabee, Marvin L. (Marlboro, MA); Buljan, Sergej-Tomislav (Acton, MA); Neil, Jeffrey T. (Acton, MA)

1991-01-01T23:59:59.000Z

100

Method and apparatus for digitally based high speed x-ray spectrometer for direct coupled use with continuous discharge preamplifiers  

DOE Patents (OSTI)

A high speed, digitally based, signal processing system is disclosed which accepts directly coupled input data from a detector with a continuous discharge type preamplifier and produces a spectral analysis of the x-rays illuminating the detector. The system`s principal elements are an analog signal conditioning section, a combinatorial logic section which implements digital triangular filtering and pileup inspection, and a microprocessor which accepts values captured by the logic section and uses them to compute x-ray energy values. Operating without pole-zero correction, the system achieves high resolution by capturing, in conjunction with each peak value from the digital filter, an associated value of the unfiltered signal, and using this latter signal to correct the former for errors which arise from its local slope terms. This correction greatly reduces both energy resolution degradation and peak centroid shifting in the output spectrum as a function of input count rate. When the noise of this correction is excessive, a modification allows two filtered averages of the signal to be captured and a corrected peak amplitude computed therefrom. 14 figs.

Warburton, W.K.

1998-06-30T23:59:59.000Z

Note: This page contains sample records for the topic "highly fractured continuous" 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

Method and apparatus for digitally based high speed x-ray spectrometer for direct coupled use with continuous discharge preamplifiers  

DOE Patents (OSTI)

A high speed, digitally based, signal processing system which accepts directly coupled input data from a detector with a continuous discharge type preamplifier and produces a spectral analysis of the x-rays illuminating the detector. The system's principal elements are an analog signal conditioning section, a combinatorial logic section which implements digital triangular filtering and pileup inspection, and a microprocessor which accepts values captured by the logic section and uses them to compute x-ray energy values. Operating without pole-zero correction, the system achieves high resolution by capturing, in conjunction with each peak value from the digital filter, an associated value of the unfiltered signal, and using this latter signal to correct the former for errors which arise from its local slope terms. This correction greatly reduces both energy resolution degradation and peak centroid shifting in the output spectrum as a function of input count rate. When the noise of this correction is excessive, a modification allows two filtered averages of the signal to be captured and a corrected peak amplitude computed therefrom.

Warburton, William K. (1300 Mills St., Menlo Park, CA 94025)

1998-01-01T23:59:59.000Z

102

Reviving Abandoned Reservoirs with High-Pressure Air Injection: Application in a Fractured and Karsted Dolomite Reservoir  

SciTech Connect

The field operator, Goldrus Producing Company, has been unable to secure funding needed to continue the field demonstration phase of the project. Accordingly, we have temporarily halted all project activities until necessary funding is obtained. Goldrus is confident that funds can be acquired by third quarter 2005 at which time it will be necessary to request a project extension to complete the originally designed study.

Robert Loucks; Stephen C. Ruppel

2005-03-31T23:59:59.000Z

103

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

SciTech Connect

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

104

Enhancing in situ bioremediation with pneumatic fracturing  

Science Conference Proceedings (OSTI)

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

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

1994-04-01T23:59:59.000Z

105

A PKN Hydraulic Fracture Model Study and Formation Permeability Determination  

E-Print Network (OSTI)

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

Xiang, Jing

2011-12-01T23:59:59.000Z

106

Optimizing reservoir management through fracture modeling  

DOE Green Energy (OSTI)

Fracture flow will become increasingly important to optimal reservoir management as exploration of geothermal reservoirs continues and as injection of spent fluid increases. The Department of Energy conducts research focused on locating and characterizing fractures, modeling the effects of fractures on movement of fluid, solutes, and heat throughout a reservoir, and determining the effects of injection on long-term reservoir production characteristics in order to increase the ability to predict with greater certainty the long-term performance of geothermal reservoirs. Improvements in interpreting and modeling geophysical techniques such as gravity, self potential, and aeromagnetics are yielding new information for the delineation of active major conduits for fluid flow. Vertical seismic profiling and cross-borehole electromagnetic techniques also show promise for delineating fracture zones. DOE funds several efforts for simulating geothermal reservoirs. Lawrence Berkeley Laboratory has adopted a continuum treatment for reservoirs with a fracture component. Idaho National Engineering Laboratory has developed simulation techniques which utilize discrete fractures and interchange of fluid between permeable matrix and fractures. Results of these research projects will be presented to industry through publications and appropriate public meetings. 9 refs.

Renner, J.L.

1988-01-01T23:59:59.000Z

107

Fracture detection and mapping  

DOE Green Energy (OSTI)

Because the costs of drilling, completing, and testing a well can be extremely high, it is important to develop better tools and methods for locating high permeability zones prior to drilling, and to develop better tools and methods for identifying and characterizing major fracture zones during the drilling and well testing stages. At the recommendation of the LBL Industry Review Panel on Geothermal Reservoir Technology, we organized and convened a one-day workshop this past July to discuss various aspects of DOE's current and planned activities in fracture detection, to review the geothermal industry's near-term and long-term research needs, to determine the priority of those needs, to disseminate to industry the status of research in progress, and to discuss the possibility of future joint research between industry and DOE. In this paper we present a brief overview of the workshop from the perspective of those who participated in it and provided us with written comments to a questionnaire that was distributed.

Goldstein, N.E.; Iovenitti, J.L.

1986-03-01T23:59:59.000Z

108

Percutaneous Vertebroplasty and Bone Cement Leakage: Clinical Experience with a New High-Viscosity Bone Cement and Delivery System for Vertebral Augmentation in Benign and Malignant Compression Fractures  

Science Conference Proceedings (OSTI)

The aim of this study was to assess the feasibility of and venous leakage reduction in percutaneous vertebroplasty (PV) using a new high-viscosity bone cement (PMMA). PV has been used effectively for pain relief in osteoporotic and malignant vertebral fractures. Cement extrusion is a common problem and can lead to complications. Sixty patients (52 female; mean age, 72.2 {+-} 7.2) suffering from osteoporosis (46), malignancy (12), and angiomas (2), divided into two groups (A and B), underwent PV on 190 vertebrae (86 dorsal, 104 lumbar). In Group A, PV with high-viscosity PMMA (Confidence, Disc-O-Tech, Israel) was used. This PMMA was injected by a proprietary delivery system, a hydraulic saline-filled screw injector. In Group B, a standard low-viscosity PMMA was used. Postprocedural CT was carried out to detect PMMA leakages and complications. Fisher's exact test and Wilcoxon rank test were used to assess significant differences (p PV was feasible, achieving good clinical outcome (p < 0.0001) without major complications. In Group A, postprocedural CT showed an asymptomatic leak in the venous structures of 8 of 98 (8.2%) treated vertebrae; a discoidal leak occurred in 6 of 98 (6.1%). In Group B, a venous leak was seen in 38 of 92 (41.3%) and a discoidal leak in 12 of 92 (13.0%). Reduction of venous leak obtained by high-viscosity PMMA was highly significant (p < 0.0001), whereas this result was not significant (p = 0.14) related to the disc. The high-viscosity PMMA system is safe and effective for clinical use, allowing a significant reduction of extravasation rate and, thus, leakage-related complications.

Anselmetti, Giovanni Carlo, E-mail: giovanni.anselmetti@ircc.i [Institute for Cancer Research and Treatment (IRCC), Interventional Radiology Unit (Italy); Zoarski, Gregg [University of Maryland, Radiology and Radiological Science (United States); Manca, Antonio [Institute for Cancer Research and Treatment (IRCC), Radiology Unit (Italy); Masala, Salvatore [University 'Tor Vergata', Radiology Unit and Interventional Radiology Unit (Italy); Eminefendic, Haris; Russo, Filippo; Regge, Daniele [Institute for Cancer Research and Treatment (IRCC), Radiology Unit (Italy)

2008-09-15T23:59:59.000Z

109

High temperature fracture and fatigue of ceramics. Annual technical report number 7, August 15, 1995--August 14, 1996  

SciTech Connect

This report covers work done in the second year of the phase of the contract. The authors focused in this period on computational models of stress redistribution effects in CMCs, high temperature experiments, and analytical models of rate dependent crack growth, including creeping fiber effects and the effects of a viscous fluid.

Cox, B.

1998-06-01T23:59:59.000Z

110

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

111

A Thermoelastic Hydraulic Fracture Design Tool for Geothermal Reservoir Development  

DOE Green Energy (OSTI)

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

Ahmad Ghassemi

2003-06-30T23:59:59.000Z

112

Experimental Study of Acid Fracture Conductivity of Austin Chalk Formation  

E-Print Network (OSTI)

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

Nino Penaloza, Andrea

2013-05-01T23:59:59.000Z

113

REVIVING ABANDONED RESERVOIRS WITH HIGH-PRESSURE AIR INJECTION: APPLICATION IN A FRACTURED AND KARSTED DOLOMITE RESERVOIR  

SciTech Connect

The Bureau of Economic Geology and Goldrus Producing Company have assembled a multidisciplinary team of geoscientists and engineers to evaluate the applicability of high-pressure air injection (HPAI) in revitalizing a nearly abandoned carbonate reservoir in the Permian Basin of West Texas. The characterization phase of the project is utilizing geoscientists and petroleum engineers from the bureau of Economic Geology and the Department of Petroleum Engineering (both at The University of Texas at Austin) to define the controls on fluid flow in the reservoir as a basis for developing a reservoir model. This model will be used to define a field deployment plant that Goldrus, a small independent oil company, will implement by drilling both vertical and horizontal wells during the demonstration phase of the project. Additional reservoir data are being gathered during the demonstration phase to improve the accuracy of the reservoir model. The results of the demonstration are being closely monitored to provide a basis for improving the design of the HPAI field deployment plan. The results of the reservoir characterization field demonstration and monitoring program will be documented and widely disseminated to facilitate adoption of this technology by oil operators in the Permian Basin and elsewhere in the US.

Robert Loucks; Steve Ruppel; Julia Gale; Jon Holder; Jon Olsen; Deanna Combs; Dhiraj Dembla; Leonel Gomez

2003-06-01T23:59:59.000Z

114

Self-potential observations during hydraulic fracturing  

SciTech Connect

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

Moore, Jeffrey R.; Glaser, Steven D.

2007-09-13T23:59:59.000Z

115

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

SciTech Connect

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

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

1997-06-01T23:59:59.000Z

116

High Btu gas from peat. A feasibility study. Part 2. Management plans for project continuation. Task 10. Final report  

Science Conference Proceedings (OSTI)

The primary objective of this task, which was the responsibility of the Minnesota Gas Company, was to determine the needs of the project upon completion of the feasibility study and determine how to implement them most effectively. The findings of the study do not justify the construction of an 80 billion Btu/day SNG from peat plant. At the present time Minnegasco will concentrate on other issues of peat development. Other processes, other products, different scales of operation - these are the issues that Minnegasco will continue to study. 3 references.

Not Available

1982-01-01T23:59:59.000Z

117

Development of the T+M coupled flow-geomechanical simulator to describe fracture propagation and coupled flow-thermal-geomechanical processes in tight/shale gas systems  

Science Conference Proceedings (OSTI)

We developed a hydraulic fracturing simulator by coupling a flow simulator to a geomechanics code, namely T+M simulator. Modeling of the vertical fracture development involves continuous updating of the boundary conditions and of the data connectivity, ... Keywords: Double porosity, Fracture propagation, Hydraulic fracturing, Poromechanics, Shale gas, Tensile failure

Jihoon Kim, George J. Moridis

2013-10-01T23:59:59.000Z

118

Deriving the shape factor of a fractured rock matrix  

SciTech Connect

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

Chang, Ming-Ming

1993-09-01T23:59:59.000Z

119

Characterization of Fractures in Geothermal Reservoirs Using Resistivity |  

Open Energy Info (EERE)

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

120

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

DOE Green Energy (OSTI)

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

Hebein, Jeffrey J.

1986-01-21T23:59:59.000Z

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


121

Feasibility of a borehole VHF radar technique for fracture mapping  

DOE Green Energy (OSTI)

Experiments were conducted to establish the feasibility of a downhole high-frequency electromagnetic technique for location of fractures in the vicinity of boreholes. An existing flame-cut slot in granite was filled with salt water to simulate a brine-filled fracture. A transmitter consisting of a phased dual-dipole array arranged to provide a directional signal toward the fracture was installed in a borehole opposite the fracture. A receiver operated at 30 to 300 MHz was also located in the same borehole. The radar returns from the simulated fracture were detectable in boreholes located at distances of up to 12 meters from the fracture. These results indicate for the first time the feasibility of a downhole VHF radar for use in a single borehole for detection of fractures located away from the borehole.

Chang, H.T.

1984-01-01T23:59:59.000Z

122

Advanced hydraulic fracturing methods to create in situ reactive barriers  

Science Conference Proceedings (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

123

Hydraulic fracturing of a moderate permeability reservoir, Kuparuk River Unit  

SciTech Connect

Sixty-five percent of the proven reserves in one of the United States' largest oil fields, the Kuparuk River Unit, are contained in the lower of two producing horizons. This zone, commonly referred to as the ''A'' sand, has a permeability of between 30 and 100 md. Unfortunately this interval is easily damaged during drilling and completion operations. Low initial flow efficiencies have been confirmed by numerous pressure transient tests. A program of hydraulic fracturing was initiated in March 1984 to overcome near wellbore damage and provide stimulation to more efficiently tap ''A'' sand reserves. More than 300 fracture stimulations have been completed to date in the arctic setting of the Kuparuk River Unit. These jobs have used a variety of fluids, proppants, and pumping schedules. The current hydraulic fracture design was evolved by continual interpretation of field results and related data from these previous stimulations. Success of the overall program has been impressive. Average post-fracture flow efficiency has been in excess of 100%. Post-fracture rate increase has averaged approximately 300%, accounting for a total rate increase of over 125,000 BOPD (19,900 m/sup 3//d). Based on these results, fracturing will continue to play an important part in future field development. This paper is the first review of the Kuparuk River Unit fracture program. It provides a case history of the development of a standard fracture design. In addition, the findings of this study would be applicable to reservoirs elsewhere with similar characteristics.

Niemeyer, B.L.; Reinart, M.R.

1986-01-01T23:59:59.000Z

124

A Rare Isolated Trapezoid Fracture  

E-Print Network (OSTI)

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

Afifi, Negean; Lu, Jenny J

2011-01-01T23:59:59.000Z

125

Hydraulic Fracturing in Particulate Materials .  

E-Print Network (OSTI)

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

Chang, Hong

2004-01-01T23:59:59.000Z

126

Fold Catastrophe Model of Fracture Propagation of Hydraulic Fracturing  

Science Conference Proceedings (OSTI)

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

Zhaowan Chun; Wan Tingting; Ai Chi; Ju Guoshuai

2010-05-01T23:59:59.000Z

127

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

E-Print Network (OSTI)

Low-permeability gas wells often produce less than predicted after a fracture treatment. One of the reasons for this is that fracture lengths calculated after stimulation are often less than designed lengths. While actual fracture lengths may be shorter due to fracture growth out of zone, improper proppant settling, or proppant flowback, short calculated fracture lengths can also result from incorrect analysis techniques. It is known that fracturing fluid that remains in the fracture and formation after a hydraulic fracture treatment can decrease the productivity of a gas well by reducing the relative permeability to gas in the region invaded by this fluid. However, the relationships between fracture fluid cleanup, effective fracture length, and well productivity are not fully understood. In this work I used reservoir simulation to determine the relationship between fracture conductivity, fracture fluid production, effective fracture length, and well productivity. I simulated water saturation and pressure profiles around a propped fracture, tracked gas production along the length of the propped fracture, and quantified the effective fracture length (i.e., the fracture length under single-phase flow conditions that gives similar performance as for multiphase flow conditions), the "cleanup" fracture length (i.e., the fracture length corresponding to 90% cumulative gas flow rate into the fracture), and the "apparent" fracture length (i.e., the fracture length where the ratio of multiphase to single-phase gas entry rate profiles is unity). This study shows that the proppant pack is generally cleaned up and the cleanup lengths are close to designed lengths in relatively short times. Although gas is entering along entire fracture, fracturing fluid remains in the formation near the fracture. The water saturation distribution affects the gas entry rate profile, which determines the effective fracture length. Subtle changes in the gas rate entry profile can result in significant changes in effective fracture length. The results I derived from this work are consistent with prior work, namely that greater fracture conductivity results in more effective well cleanup and longer effective fracture lengths versus time. This study provides better explanation of mechanisms that affect fracturing fluid cleanup, effective fracture length, and well productivity than previous work.

Lolon, Elyezer P.

2004-12-01T23:59:59.000Z

128

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

SciTech Connect

The company began fracturing diatomaceous earth zones in the San Joaquin Valley (CA) in 1976. Fracturing has proved an effective method of exploiting these previously noncommercial reservoirs. Nevertheless, productivity behavior is typified by high initial rates followed by rapid decline. Reasons for this decline have been evaluated and are discussed. Also discussed are laboratory experiments performed to determine an appropriate fracture design for this formation.

Strubhar, M.K.; Andreani, F.S.; Medlin, W.L.; Nabi, S.M.

1984-03-01T23:59:59.000Z

129

Fracturing fluids -- then and now  

Science Conference Proceedings (OSTI)

Fracturing fluid provides the means by which the hydraulic fracturing process can take place. All applications of well stimulation by fracturing must include selection of fracturing fluid in the initial phases of fracture design and treatment planning. Fracturing fluid has two important purposes: (1) to provide sufficient viscosity to suspend and transport proppant deep into the created fracture system and (2) to decompose, or break, chemically to a low viscosity to allow flowback of a major part of the fluid to the surface for fracture cleanup after the treatment is completed. Because of the importance of its rheological properties and behavior in the fracture under reservoir conditions during (and immediately after) the treatment, service company research laboratories have spent millions of dollars on R and D of fracturing fluids.

Jennings, A.R. Jr. [Enhanced Well Stimulation Inc., Plano, TX (United States)

1996-07-01T23:59:59.000Z

130

Suspensions in hydraulic fracturing  

Science Conference Proceedings (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

131

Geomechanical Development of Fractured Reservoirs During Gas Production  

E-Print Network (OSTI)

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

Huang, Jian

2013-05-01T23:59:59.000Z

132

Transport of conservative solutes in simulated fracture networks: 1. Synthetic data generation  

E-Print Network (OSTI)

. By deterministically mapping individual fractures onto a highly discretized finite difference grid (1 m Ã? 1 m Ã? 1 m length, transmissivity, density, and orientation. A fracture continuum approach using MODFLOW

Meerschaert, Mark M.

133

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

Science Conference Proceedings (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 more efficient CO{sub 2} flooding in heterogeneous or fracture-dominated reservoirs. To achieve this objective, we divided the report into two chapters. The first chapter was to image and perform experimental investigation of transfer mechanisms during CO{sub 2} flooding in NFR and HFR using X-ray CT scanner. In this chapter, we emphasized our work on understanding the connection between fracture properties and fundamentals of transfer mechanism from matrix to fractures and fluid flow through fracture systems. We started our work by investigating the effect of different overburden pressures and stress-state conditions on rock properties and fluid flow. Since the fracture aperture is one of important parameter that governs the fluid flow through the fracture systems, the average fracture aperture from the fluid flow experiments and fracture aperture distribution derived from X-ray CT scan were estimated for our modeling purposes. The fracture properties and fluid flow have significant changes in response to different overburden pressures and stress-state conditions. The fracture aperture distribution follows lognormal distribution even at elevated stress conditions. Later, we also investigated the fluid transfers between matrix and fracture that control imbibition process. We evaluated dimensionless time for validating the scheme of upscaling laboratory experiments to field dimensions. In CO{sub 2} injection experiments, the use of X-ray CT has allowed us to understand the mechanisms of CO{sub 2} flooding process in fractured system and to take important steps in reducing oil bypassed. When CO{sub 2} flooding experiments were performed on a short core with a fracture at the center of the core, the gravity plays an important role in the recovery of oil even in a short matrix block. This results are contrary with the previous believes that gravity drainage has always been associated with tall matrix blocks. In order to reduce oil bypassed, we injected water that has been viscosified with a polymer into the fracture to divert CO{sub 2} flow into matrix and delay CO{sub 2} breakthrough. Although the breakthrough time reduced considerably, water ''leak off'' into the matrix was very high. A cross-linked gel was used in the fracture to avoid this problem. The gel was found to overcome ''leak off'' problems and effectively divert CO{sub 2} flow into the matrix. As part of our technology transfer activity, we investigated the natural fracture aperture distribution of Tensleep formation cores. We found that the measured apertures distributions follow log normal distribution as expected. The second chapter deals with analysis and modeling the laboratory experiments and fluid flow through fractured networks. We derived a new equation to determine the average fracture aperture and the amount of each flow through fracture and matrix system. The results of this study were used as the observed data and for validating the simulation model. The idea behind this study is to validate the use of a set of smooth parallel plates that is common in modeling fracture system. The results suggest that fracture apertures need to be distributed to accurately model the experimental results. In order to study the imbibition process in details, we developed imbibition simulator. We validated our model with X-ray CT experimental data from different imbibition experiments. We found that the proper simulation model requires matching both weight gain and CT water saturation simultaneously as oppose to common practices in matching imbibition process with weight gain only because of lack information from CT scan. The work was continued by developing dual porosity simulation using empirical transfer function (ETF) derived from imbibition experiments. This allows reduction of uncertainty parameter in modeling transfer of fluids from matrix to the fra

David S. Schechter

2005-09-28T23:59:59.000Z

134

Mapping Fractures In The Medicine Lake Geothermal System | Open Energy  

Open Energy Info (EERE)

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

135

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

136

Self-potential observations during hydraulic fracturing  

E-Print Network (OSTI)

and T. W. Keech (1977), Hydraulic fracture mapping usingpotential measurements during hydraulic fracturing of BunterSP Monitoring during hydraulic fracturing using the TG-2

Moore, Jeffrey R.; Glaser, Steven D.

2008-01-01T23:59:59.000Z

137

Hydraulic Fracturing Poster | Department of Energy  

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

Hydraulic Fracturing Poster Hydraulic Fracturing Poster Educational poster graphically displaying the key components of hydraulic fracturing. Teachers: If you would like hard...

138

Twin-belt continuous caster with containment and cooling of the exiting cast product for enabling high-speed casting of molten-center product  

DOE Patents (OSTI)

In continuously casting molten metal into cast product by a twin-belt machine, it is desirable to achieve dramatic increases in speed (linear feet per minute) at which cast product exits the machine, particularly in installations where steel cast product is intended to feed a downstream regular rolling mill (as distinct from a planetary mill) operating in tandem with the twin-belt caster. Such high-speed casting produces product with a relatively thin shell and molten interior, and the shell tends to bulge outwardly due to metallostatic head pressure of the molten center. A number of cooperative features enable high-speed, twin-belt casting: (1) Each casting belt is slidably supported adjacent to the caster exit pulley for bulge control and enhanced cooling of cast product. (2) Lateral skew steering of each belt provides an effective increase in moving mold length plus a continuity of heat transfer not obtained with prior art belt steering apparatus. (3) The exiting slab is contained and supported downstream from the casting machine to prevent bulging of the shell of the cast product, and (4) spray cooling is incorporated in the exit containment apparatus for secondary cooling of cast product.

Dykes, Charles D. (303 Shore Rd., Milton, VT); Daniel, Sabah S. (303 Shore Rd., Pittsburgh, PA); Wood, J. F. Barry (303 Shore Rd., Burlington, VT 05401)

1990-02-20T23:59:59.000Z

139

Microscale controlled continuous cell culture  

E-Print Network (OSTI)

Measurements of metabolic and cellular activity through substrate and product interactions are highly dependent on environmental conditions and cellular metabolic state. For such experiments to be feasible, continuous ...

Lee, Kevin Shao-Kwan

2011-01-01T23:59:59.000Z

140

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

E-Print Network (OSTI)

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

Kamenov, Anton

2013-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "highly fractured continuous" 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
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141

Comparison of pressure ransient response in intensely and sparsely fractured reservoirs  

DOE Green Energy (OSTI)

A comprehensive analytical model is presented to study the pressure transient behavior of a naturally fractured reservoir with a continuous matrix block size distribution. Geologically realistic probability density functions of matrix block size are used to represent reservoirs of varying fracture intensity and uniformity. Transient interporosity flow is assumed and interporosity skin is incorporated. Drawdown and interference pressure transient tests are investigated. The results show distinctions in the pressure response from intensely and sparsely fractured reservoirs in the absence of interporosity skin. Also, uniformly and nonuniformly fractured reservoirs exhibit distinct responses, irrespective of the degree of fracture intensity. The pressure response in a nonuniformly fractured reservoir with large block size variability, approaches a nonfractured (homogeneous) reservoir response. Type curves are developed to estimate matrix block size variability and the degree of fracture intensity from drawdown and interference well tests.

Johns, R.T.

1989-01-01T23:59:59.000Z

142

Comparison of pressure transient response in intensely and sparsely fractured reservoirs  

DOE Green Energy (OSTI)

A comprehensive analytical model is presented to study the pressure transient behavior of a naturally fractured reservoir with a continuous matrix block size distribution. Geologically realistic probability density functions of matrix block size are used to represent reservoirs of varying fracture intensity and uniformity. Transient interporosity flow is assumed and interporosity skin is incorporated. Drawdown and interference pressure transient tests are investigated. The results show distinctions in the pressure response from intensely and sparsely fractured reservoirs in the absence of interporosity skin. Also, uniformly and nonuniformly fractured reservoirs exhibit distinct responses, irrespective of the degree of fracture intensity. The pressure response in a nonuniformly fractured reservoir with large block size variability, approaches a nonfractured (homogeneous) reservoir response. Type curves are developed to estimate matrix block size variability and the degree of fracture intensity from drawdown and interference well tests.

Johns, R.T.

1989-04-01T23:59:59.000Z

143

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

Science Conference Proceedings (OSTI)

This report describes the work performed during the fourth year of the project, ''Investigating of Efficiency Improvements during CO{sub 2} Injection in Hydraulically and Naturally Fractured Reservoirs.'' The objective of this project is to perform unique laboratory experiments with artificially fractured cores (AFCs) and X-ray CT scanner to examine the physical mechanisms of bypassing in hydraulically fractured reservoirs (HFR) and naturally fractured reservoirs (NFR) that eventually result in more efficient CO{sub 2} flooding in heterogeneous or fracture-dominated reservoirs. In Chapter 1, we worked with DOE-RMOTC to investigate fracture properties in the Tensleep Formation at Teapot Dome Naval Reserve as part of their CO{sub 2} sequestration project. In Chapter 2, we continue our investigation to determine the primary oil recovery mechanism in a short vertically fractured core. Finally in Chapter 3, we report our numerical modeling efforts to develop compositional simulator with irregular grid blocks.

David S. Schechter

2005-04-27T23:59:59.000Z

144

Fracturing operations in a dry geothermal reservoir  

DOE Green Energy (OSTI)

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

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

1983-01-01T23:59:59.000Z

145

Breakthrough in fracture mechanics  

SciTech Connect

Fracture mechanics, the science of calculating material characteristics, stress, and flaws in plant equipment to evaluate structural integrity, usually spares the owners of nuclear power plants unnecessary expense. Instead of replacing equipment prematurely or waiting for costly, unscheduled materials failures that can take months to repair and cost thousands of dollars a day for replacement power, utilities use fracture mechanics techniques to carefully consider their options. If analyses show repair is unnecessary, plant operation can confidently be resumed. If repair is required, it can either be done immediately or, if deferrable, be scheduled for a later, more convenient outage.

Lihach, N.

1981-05-01T23:59:59.000Z

146

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

SciTech Connect

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

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

1995-06-01T23:59:59.000Z

147

Rigid Body Simulation with Local Fracturing Effects  

Science Conference Proceedings (OSTI)

Focusing on the real-time and interactive ability features in the Virtual Reality application, we propose a fracture pattern based on local fracture mechanism. Taking advantage of the experience analysis or the offline computation verified fracture characteristic, ... Keywords: Rigid Body, pre-fracture, fracture pattern, local fracture, dynamics

Wu Bo; Zeng Liang; Wu Yagang

2011-05-01T23:59:59.000Z

148

Advanced Hydraulic Fracturing Technology for Unconventional Tight Gas Reservoirs  

Science Conference Proceedings (OSTI)

The objectives of this project are to develop and test new techniques for creating extensive, conductive hydraulic fractures in unconventional tight gas reservoirs by statistically assessing the productivity achieved in hundreds of field treatments with a variety of current fracturing practices ranging from 'water fracs' to conventional gel fracture treatments; by laboratory measurements of the conductivity created with high rate proppant fracturing using an entirely new conductivity test - the 'dynamic fracture conductivity test'; and by developing design models to implement the optimal fracture treatments determined from the field assessment and the laboratory measurements. One of the tasks of this project is to create an 'advisor' or expert system for completion, production and stimulation of tight gas reservoirs. A central part of this study is an extensive survey of the productivity of hundreds of tight gas wells that have been hydraulically fractured. We have been doing an extensive literature search of the SPE eLibrary, DOE, Gas Technology Institute (GTI), Bureau of Economic Geology and IHS Energy, for publicly available technical reports about procedures of drilling, completion and production of the tight gas wells. We have downloaded numerous papers and read and summarized the information to build a database that will contain field treatment data, organized by geographic location, and hydraulic fracture treatment design data, organized by the treatment type. We have conducted experimental study on 'dynamic fracture conductivity' created when proppant slurries are pumped into hydraulic fractures in tight gas sands. Unlike conventional fracture conductivity tests in which proppant is loaded into the fracture artificially; we pump proppant/frac fluid slurries into a fracture cell, dynamically placing the proppant just as it occurs in the field. From such tests, we expect to gain new insights into some of the critical issues in tight gas fracturing, in particular the roles of gel damage, polymer loading (water-frac versus gel frac), and proppant concentration on the created fracture conductivity. To achieve this objective, we have designed the experimental apparatus to conduct the dynamic fracture conductivity tests. The experimental apparatus has been built and some preliminary tests have been conducted to test the apparatus.

Stephen Holditch; A. Daniel Hill; D. Zhu

2007-06-19T23:59:59.000Z

149

Effect of Light Water Reactor Environments on Fracture Resistance in Irradiated Stainless Steel  

Science Conference Proceedings (OSTI)

Austenitic stainless steels are used extensively for the fabrication of reactor internal components due to their high strength and fracture toughness. However, the fracture properties of these materials degrade with exposure to neutron irradiation. The effects on the reduction of fracture properties may depend on neutron fluence, cold work, corrosion potential, water purity, temperature, and loading. The exact role of these environmental parameters remains unclear.Fracture toughness ...

2012-09-20T23:59:59.000Z

150

Continuation of full-scale three-dimensional numerical experiments on high-intensity particle and laser beam-matter interactions  

SciTech Connect

We present results from the grant entitled, ���¢��������Continuation of full-scale three-dimensional numerical experiments on high-intensity particle and laser beam-matter interactions.���¢������� The research significantly advanced the understanding of basic high-energy density science (HEDS) on ultra intense laser and particle beam plasma interactions. This advancement in understanding was then used to to aid in the quest to make 1 GeV to 500 GeV plasma based accelerator stages. The work blended basic research with three-dimensions fully nonlinear and fully kinetic simulations including full-scale modeling of ongoing or planned experiments. The primary tool was three-dimensional particle-in-cell simulations. The simulations provided a test bed for theoretical ideas and models as well as a method to guide experiments. The research also included careful benchmarking of codes against experiment. High-fidelity full-scale modeling provided a means to extrapolate parameters into regimes that were not accessible to current or near term experiments, thereby allowing concepts to be tested with confidence before tens to hundreds of millions of dollars were spent building facilities. The research allowed the development of a hierarchy of PIC codes and diagnostics that is one of the most advanced in the world.

Mori, Warren, B.

2012-12-01T23:59:59.000Z

151

Evaluation of borehole electromagnetic and seismic detection of fractures  

DOE Green Energy (OSTI)

Experiments were conducted to establish the feasibility of downhole high-frequency techniques for location of fractures in the vicinity of boreholes. An existing flame-cut slot in granite was filled with salt water to simulate a brine-filled fracture. The first method used an electromagnetic wave at 30 to 300 MHz, vhf frequencies. A transmitter consisting of a phased dual-dipole array arranged to provide a directional signal toward the fracture was installed in a borehole opposite the fracture. A receiver was also located in the same borehole. The radar returns from the simulated fracture were detectable in boreholes located at distances of up to 12 meters from the fracture. These results indicate for the first time the feasibility of a downhole vhf radar for use in a single borehole for detection of fractures located away from the borehole. Similar experiments were also conducted using seismic waves at 4.5 to 6 KHz. The transmitter and the receiver in this case were located in separate boreholes. During this experiment, reflections from the slot were obtained only with the transducers oriented for shear wave illumination and detection. These results suggest that a high-frequency shear wave can also be used to detect fractures away from a borehole.

Chang, H.T.; Suhler, S.A.; Owen, T.E.

1984-02-01T23:59:59.000Z

152

On the fracture toughness of advanced materials  

Science Conference Proceedings (OSTI)

Few engineering materials are limited by their strength; rather they are limited by their resistance to fracture or fracture toughness. It is not by accident that most critical structures, such as bridges, ships, nuclear pressure vessels and so forth, are manufactured from materials that are comparatively low in strength but high in toughness. Indeed, in many classes of materials, strength and toughness are almost mutually exclusive. In the first instance, such resistance to fracture is a function of bonding and crystal structure (or lack thereof), but can be developed through the design of appropriate nano/microstructures. However, the creation of tough microstructures in structural materials, i.e., metals, polymers, ceramics and their composites, is invariably a compromise between resistance to intrinsic damage mechanisms ahead of the tip of a crack (intrinsic toughening) and the formation of crack-tip shielding mechanisms which principally act behind the tip to reduce the effective 'crack-driving force' (extrinsic toughening). Intrinsic toughening is essentially an inherent property of a specific microstructure; it is the dominant form of toughening in ductile (e.g., metallic) materials. However, for most brittle (e.g., ceramic) solids, and this includes many biological materials, it is largely ineffective and toughening conversely must be developed extrinsically, by such shielding mechanisms as crack bridging. From a fracture mechanics perspective, this results in toughening in the form of rising resistance-curve behavior where the fracture resistance actually increases with crack extension. The implication of this is that in many biological and high-strength advanced materials, toughness is developed primarily during crack growth and not for crack initiation. This is an important realization yet is still rarely reflected in the way that toughness is measured, which is invariably involves the use of single-value (crack-initiation) parameters such as the fracture toughness K{sub Ic}.

Launey, Maximilien E.; Ritchie, Robert O.

2008-11-24T23:59:59.000Z

153

Effective fracture geometry obtained with large water sand ratio  

E-Print Network (OSTI)

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

Kumar, Amrendra

2008-12-01T23:59:59.000Z

154

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

Science Conference Proceedings (OSTI)

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

NONE

1996-12-31T23:59:59.000Z

155

A Physically Based Approach for Modeling Multiphase Fracture-Matrix Interaction in Fractured Porous Media  

E-Print Network (OSTI)

in modeling multiphase flow in porous and fractured media,multiphase tracer transport in heterogeneous fractured porousof multiphase flow through fractured or porous media.

Wu, Yu-Shu; Pan, Lehua; Pruess, Karsten

2004-01-01T23:59:59.000Z

156

A physically based numerical approach for modeling fracture-matrix interaction in fractured reservoirs  

E-Print Network (OSTI)

in modeling multiphase flow in porous and fractured media,multiphase tracer transport in heterogeneous fractured porousof multiphase flow through fractured or porous media. 3.

Wu, Yu-Shu; Pruess, Karsten

2004-01-01T23:59:59.000Z

157

Hydraulic fracture experiments in GT-1 and GT-2  

DOE Green Energy (OSTI)

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

Aamodt, R.L.

1977-02-01T23:59:59.000Z

158

Numerical Investigation of Interaction Between Hydraulic Fractures and Natural Fractures  

E-Print Network (OSTI)

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

Xue, Wenxu

2010-12-01T23:59:59.000Z

159

Continuous plutonium dissolution apparatus  

DOE Patents (OSTI)

This invention is concerned with continuous dissolution of metals such as plutonium. A high normality acid mixture is fed into a boiler vessel, vaporized, and subsequently condensed as a low normality acid mixture. The mixture is then conveyed to a dissolution vessel and contacted with the plutonium metal to dissolve the plutonium in the dissolution vessel, reacting therewith forming plutonium nitrate. The reaction products are then conveyed to the mixing vessel and maintained soluble by the high normality acid, with separation and removal of the desired constituent. (Official Gazette)

Meyer, F.G.; Tesitor, C.N.

1974-02-26T23:59:59.000Z

160

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

Note: This page contains sample records for the topic "highly fractured continuous" 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

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

E-Print Network (OSTI)

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

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

2000-01-01T23:59:59.000Z

162

Analysis Of Macroscopic Fractures In Granite In The Hdr Geothermal Well  

Open Energy Info (EERE)

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

163

Continual Learning | Department of Energy  

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

Continual Learning Continual Learning Continual Learning Continual Learning Workshops Continual Learning is a change initiative which is used to help develop and grow a learning culture within DOE. The purpose of Continual Learning is to improve the professional development of our federal workforce. In an effort to support this initiative, HC-20 offers 3 instructional workshops, located under additional information, to assist employees and supervisors with employee development. These workshops are full of helpful tips and tricks for identifying low cost/no cost training, creating a high-quality IDP and assist supervisors with their responsibilities with employee development. Employees and supervisor are encouraged to attend these workshops and let us (HC-20) help you as we promote a learning

164

Practical simulation of hierarchical brittle fracture  

Science Conference Proceedings (OSTI)

A novel practical method for brittle fracture simulation is presented. Our fracture model is represented by a tree structure, and all elementary fracture pieces are hierarchically connected. Each node in a fracture tree has a glue table to define connections ... Keywords: fluid, fracture, rigid body

Seungtaik Oh; Seunghyup Shin; Hyeryeong Jun

2012-05-01T23:59:59.000Z

165

Measuring and Modeling Flow in Welded Fractured Tuffs  

SciTech Connect

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

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

2001-10-03T23:59:59.000Z

166

Wormhole formation in dissolving fractures  

E-Print Network (OSTI)

We investigate the dissolution of artificial fractures with three-dimensional, pore-scale numerical simulations. The fluid velocity in the fracture space was determined from a lattice-Boltzmann method, and a stochastic solver was used for the transport of dissolved species. Numerical simulations were used to study conditions under which long conduits (wormholes) form in an initially rough but spatially homogeneous fracture. The effects of flow rate, mineral dissolution rate and geometrical properties of the fracture were investigated, and the optimal conditions for wormhole formation determined.

Szymczak, P

2009-01-01T23:59:59.000Z

167

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… (more)

Hervas Ordonez, Rafael Alejandro

2012-01-01T23:59:59.000Z

168

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

SciTech Connect

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

Ahmad Ghassemi

2009-10-01T23:59:59.000Z

169

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

SciTech Connect

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

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

1982-09-01T23:59:59.000Z

170

Experimental study of the transition from brittle shear fractures to joints  

E-Print Network (OSTI)

Current geologic thinking is that there are two, and only two, distinct types of brittle fractures, joints and shear fractures (faults). For over half a century, it has been debated that a third type of fracture, referred to as hybrid fractures, could exist and that joints and shear fractures may be end members of a continuous spectrum of brittle fractures. Hybrid fractures are hypothesized to form under mixed compressive and tensile stress states and have structural characteristics intermediate to those of joints and shear fractures. While this hypothesis is accepted in many modern structural geology textbooks used at the college and graduate level, no unchallenged evidence exists for the existence of hybrid fractures. Following the general methodology of a previously performed study by W.F. Brace (1964), but incorporating several key modifications to the experimental methods, a series of dog-bone triaxial experiments were performed on Carrara marble at room temperature, an axial extension rate of 2x10?² mm s?¹, and confining pressures between 7.5 and 170 MPa. The experiments provide strong evidence for the existence of hybrid fractures on the basis of the progressive change in fracture orientation, surface morphology, and failure strength between end-member joints and shear fractures. At the lowest confining pressures (7.5 to 60 MPa), fractures are oriented approximately parallel to the maximum principal stress, []?, form at an axial stress []?, of approximately -7.75 MPa (i.e. the uniaxial tensile strength), and display fracture surfaces characterized by many reflective cleavage faces, consistent with jointing. At the highest confining pressures (130 to 170 MPa), fractures are oriented from 13.4? to 21.6? to []?, form under completely compressive stress states with []? between 0 and 4.3 MPa, and are characterized by powdery white surfaces with short slip lineations, consistent with shear fracturing. At intermediate confining pressures (70 to 120 MPa), fractures are oriented from 3.7? to 12.4? to []?, form under mixed stress conditions with s3 ranging from -10.6 to -3.0 MPa, and display both reflective cleavage faces and powdery white surfaces with short slip lineations, consistent with hybrid fracturing.

Ramsey, Jonathan Michael

2003-01-01T23:59:59.000Z

171

Using Chemicals to Optimize Conformance Control in Fractured Reservoirs  

SciTech Connect

The objectives of this project are: (1) to develop a capability to predict and optimize the ability of gels to reduce permeability to water more than that to oil or gas, (2) to develop procedures for optimizing blocking agent placement in wells where hydraulic fractures cause channeling problems, and (3) to develop procedures to optimize blocking agent placement in naturally fractured reservoirs. Work was directed at both injection wells and production wells and at vertical, horizontal, and highly deviated wells.

Seright, Randall; Liang, Jenn-Tai; Schrader, Richard; Hagstrom II, John; Wang, Ying; Kumar, Anand; Wavrik, Kathryn

2001-09-07T23:59:59.000Z

172

NETL: Discrete Fracture Reservoir Simulation Software  

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

Discrete Fracture Reservoir Simulation FRACGENNFFLOW Shale Gas Flow Simulation Shale Gas Flow Simulation FRACGENNFFLOW, a fractured reservoir modeling software developed by the...

173

Self-potential observations during hydraulic fracturing  

E-Print Network (OSTI)

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

Moore, J R; Glaser, Steven D

2007-01-01T23:59:59.000Z

174

Some Fundamental Mechanisms of Hydraulic Fracturing .  

E-Print Network (OSTI)

??This dissertation focuses mainly on three topics: (1) mixed-mode branching and segmentation of hydraulic fractures in brittle materials, (2) hydraulic fracture propagation in particulate materials,… (more)

Wu, Ruiting

2006-01-01T23:59:59.000Z

175

Shale Gas Development Challenges: Fracture Fluids | Department...  

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

Centers Field Sites Power Marketing Administration Other Agencies You are here Home Shale Gas Development Challenges: Fracture Fluids Shale Gas Development Challenges: Fracture...

176

“Hanging” Pelvic Gallbladder Simulating Occult Hip Fracture Versus Appendicitis  

E-Print Network (OSTI)

Pelvic Gallbladder Simulating Occult Hip Fracture Versuspossibility of either an occult hip fracture or a subacute

Dolbec, Katherine W D; Higgins, George L; Jung, Michale W

2010-01-01T23:59:59.000Z

177

Hydraulic-fracture stimulation treatments at East Mesa, Well 58-30. Geothermal-reservoir well-stimulation program  

DOE Green Energy (OSTI)

East Mesa Well 58-30 was selected for two stimulation treatments: a conventional hydraulic fracture in a deep, low permeability interval, and a dendritic fracture in a shallow, high permeability interval of completion. The well selection, pre-stimulation evaluation, fracture treatment design, and post-stimulation evaluation are presented.

Not Available

1981-02-01T23:59:59.000Z

178

Lisburne Formation fracture characterization and flow modeling  

E-Print Network (OSTI)

Evaluation of fractured reservoirs for fluid flow and optimal well placement is often very complicated. In general, fractures enhance permeability and increase access to matrix surface, but their random aspects create difficulties for analysis and performance prediction. Each reservoir has unique aspects which require individual assessment. This study examined fracture properties in a part of the Carboniferous Lisburne Formation. Field study of outcrops yielded information on two sets of large-scale fractures (NNW and ENE orientations) from the lower Wahoo Limestone in the eastern Sadlerochit Mountains. Several statistical methods were used on these data to find appropriate models describing the megafracture properties. For NNW fracture height and ENE fracture spacing, the gamma model appears to adequately describe the distribution. NNW fracture spacing and ENE fracture height are lognormally distributed. Results of the statistical analyses were used as input for fracture set generation and modeling using "FracMan". Modeling different borehole orientations in the fractured domain revealed that horizontal wells with 60? azimuth have an optimal trajectory, resulting in the maximum number and area of fracture connections. The orientation maximizing the number of fracture connections did not necessarily give the maximum area. Conductivity analysis showed that the fracture network is weakly anisotropic and above the percolation threshold. The fracture conductance is strongly dependent on the NNW fracture set; larger fractures influence fluid flow more than smaller fractures. Fracture strike and dip variability increased the system interconnectivity, but did not affect the optimal wellbore orientation. Incorporating ENE fracture termination against the NNW fractures decreased the system conductance and shifted the optimal wellbore trajectory towards the direction perpendicular to the NNW set. Reservoir engineering implications of this study include: guidelines for optimal wellbore orientations, the relative placement of injectors and producers along the bisectors between the two fracture sets, and the importance of including fracture terminations. Further work should investigate the influence of variations in fracture aperture and transmissivities, and drainage area, and extend the analysis to additional units of the Lisburne Group.

Karpov, Alexandre Valerievich

2001-01-01T23:59:59.000Z

179

Relative Permeability of Fractured Rock  

DOE Green Energy (OSTI)

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

Mark D. Habana

2002-06-30T23:59:59.000Z

180

Fully Coupled Geomechanics and Discrete Flow Network Modeling of Hydraulic Fracturing for Geothermal Applications  

DOE Green Energy (OSTI)

The primary objective of our current research is to develop a computational test bed for evaluating borehole techniques to enhance fluid flow and heat transfer in enhanced geothermal systems (EGS). Simulating processes resulting in hydraulic fracturing and/or the remobilization of existing fractures, especially the interaction between propagating fractures and existing fractures, represents a critical goal of our project. To this end, we are continuing to develop a hydraulic fracturing simulation capability within the Livermore Distinct Element Code (LDEC), a combined FEM/DEM analysis code with explicit solid-fluid mechanics coupling. LDEC simulations start from an initial fracture distribution which can be stochastically generated or upscaled from the statistics of an actual fracture distribution. During the hydraulic stimulation process, LDEC tracks the propagation of fractures and other modifications to the fracture system. The output is transferred to the Non-isothermal Unsaturated Flow and Transport (NUFT) code to capture heat transfer and flow at the reservoir scale. This approach is intended to offer flexibility in the types of analyses we can perform, including evaluating the effects of different system heterogeneities on the heat extraction rate as well as seismicity associated with geothermal operations. This paper details the basic methodology of our approach. Two numerical examples showing the capability and effectiveness of our simulator are also presented.

Fu, P; Johnson, S M; Hao, Y; Carrigan, C R

2011-01-18T23:59:59.000Z

Note: This page contains sample records for the topic "highly fractured continuous" 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

Fracturing Fluid Characterization Facility  

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

Documentation Page Documentation Page 1. Report No. DE - FC 21 - 92MC29077 2. 3. Recipient's Accession No. 5. Report Date August 31, 2000 4. Title and Subtitle Fracturing Fluid Characterization Facility 6. 7. Author(s) The University of Oklahoma 8. Performing Organization Rept. No. 10. Project/Task/Work Unit No. 9. Performing Organization Name and Address The University of Oklahoma Sarkeys Energy Center T301 100 E Boyd St Norman, OK 73019 11. Contract (C) or Grant (G) No. DOE:DE FC21 92 MC29077 13. Type of Report & Period Covered Final Report 09 30 92 - 03 31 00 12. Sponsoring Organization Name and Address US Dept of Energy - FETL 3610 Collins Ferry Road Morgantown, WV 26505 14. 15. Supplementary Notes Several technical papers were prepared and presented at various Society of Petroleum Engineers Conferences and US

182

Explosive fracturing method  

SciTech Connect

A method of inducing a fracture system and multiple cavities in earthen formations is described. A first explosive, preferably nuclear, is buried at a sufficient depth so that its subsequent detonation is fully contained within the earth. Thereafter a second explosive, also preferably nuclear, is buried a predetermined distance from the situs of the first explosive. After detonation of the first explosive, time is allowed to elapse during which the cavity formed by the first explosive collapses to form a rubblized chimney. Thereafter, the second explosive is detonated to create a second chimney parallel to that of the first explosive together with a zone of enhanced permeability between the first and second. (10 claims)

Boardman, C.R.; Knutson, C.F.

1973-12-11T23:59:59.000Z

183

Design and Some Properties of Continuous Fiber-Reinforced ZrB2 ...  

Science Conference Proceedings (OSTI)

Carbon Nanofiber Reinforced Polymer Derived Ceramic Nanocomposites · Changes ... Crack Growth, Modeling of Fracture Resistance, and Designing Ceramic Matrix ... High-Temperature Stress Rupture of Ceramic Matrix Composites under ...

184

Elastic incompatibility stresses across planar and nonplanar grain boundaries in silver, aluminum, and zirconium applied to ductile fracture criteria under high triaxial stress  

Science Conference Proceedings (OSTI)

Grain boundaries in a polycrystal imply elastic incompatibilities that can lead to stress states in the vicinity of the interface that are different from the macroscopic or applied stresses because the single crystal elastic properties are not all isotropic. This phenomenon is important as mechanical processes may operate at the microscopic level that would not be predicted based on the macroscopic stress state. This phenomenon has not been widely examined. One of the few studies that examined the level of stress- state modification on copper determined that slip or plasticity in cyclically deformed copper occurred in areas with high elastic incompatibility stresses. The focus of the present study is the unstable growth of cavities as a result of high local triaxial stress. Grain boundaries in silver, aluminum, and zirconium are examined.

Roehnelt, R.; Kassner, M.E.; Kennedy, T.C. [Oregon State Univ., Corvallis, OR (United States); Rosen, R.S. [Lawrence Livermore National Lab., CA (United States)

1996-07-01T23:59:59.000Z

185

SPALL FRACTURE AND SPALL FRACTURE AND COMPACTION COMPACTION  

National Nuclear Security Administration (NNSA)

SPALL FRACTURE AND SPALL FRACTURE AND SPALL FRACTURE AND SPALL FRACTURE AND COMPACTION COMPACTION IN NATURAL URANIUM IN NATURAL URANIUM UNDER SHOCK UNDER SHOCK - - WAVE LOADING WAVE LOADING O.A. O.A. Tyupanova Tyupanova , S.S. , S.S. Nadezhin Nadezhin , A.N. , A.N. Malyshev Malyshev , , O.N. O.N. Ignatova Ignatova , V.I. , V.I. Skokov Skokov , V.N. , V.N. Knyazev Knyazev , , V.A. V.A. Raevsky Raevsky , N.A. , N.A. Yukina Yukina Russian Federal Nuclear Center Russian Federal Nuclear Center - - VNIIEF, VNIIEF, Sarov Sarov , Russia , Russia Introduction Introduction  Nucleation and growth of defects inside a solid under pulse tensile stresses signify a necessity to consider it as a damaged medium.  A certain volume of experimental data, obtained in correct tests, which are sensitive to a characteristic under study, is necessary

186

Welding and Repair Technology Center: High Chromium Ni-base Filler Metal Evaluation using the Strain-to-Fracture Test Method  

Science Conference Proceedings (OSTI)

Higher chromium, nickel-base alloys (2830% Cr) have been promoted for weld overlay applications, new construction, and applications to replace 82/182 filler material. New alloys developed to meet the required Cr levelincluding filler metal 52 (ERNiCrFe-7) and later heats of filler metal 52M (ERNiCrFe-7a)did not have the same weldability as its predecessor 82 (ERNiCrFe-3). A key welding issue was ductility dip cracking (DDC), which is the result of low grain boundary strength at high temperatures. DDC res...

2008-12-19T23:59:59.000Z

187

Well fracturing method using liquefied gas as fracturing fluid  

SciTech Connect

A method is described for fracturing an oil well or gas well with a mixture of liquid carbon dioxide and liquid petroleum gas. The objective is to be able to inject the liquid into the well bore at a relatively high pumping rate without causing the liquid to boil. Prior to injection, both the liquid CO/sub 2/ and the LPG are held in separate supply tanks at a temperature and pressure at which the liquid phase will not boil. The temperature of the LPG is substantially higher than the liquid CO/sub 2/. During the pumping operation, part of the liquid CO/sub 2/ and all of the LPG are fed through a heat exchanger. In the exchanger, the amount of heat transferred from the LPG to the liquid CO/sub 2/ is enough to vaporize the liquid. The CO/sub 2/ vapor is then circulated back into the CO/sub 2/ tank. The recycled vapor thus maintains the liquid-vapor phase in the tank at equilibrium, so that the liquid will not boil at the desired pumping rate. (4 claims)

Zingg, W.M.; Grassman, D.D.

1974-10-22T23:59:59.000Z

188

TMS Continuing Education Home  

Science Conference Proceedings (OSTI)

TMS Continuing Education Home. TMS is dedicated to encouraging the lifelong education of materials science and engineering professionals through ...

189

Temporary Sealing of Fractures | Open Energy Information  

Open Energy Info (EERE)

Temporary Sealing of Fractures Temporary Sealing of Fractures Jump to: navigation, search Contents 1 Geothermal Lab Call Projects for Temporary Sealing of Fractures 2 Geothermal ARRA Funded Projects for Temporary Sealing of Fractures Geothermal Lab Call Projects for Temporary Sealing of Fractures Loading map... {"format":"googlemaps3","type":"ROADMAP","types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"limit":200,"offset":0,"link":"all","sort":[""],"order":[],"headers":"show","mainlabel":"","intro":"","outro":"","searchlabel":"\u2026

190

Ductile Fracture Handbook: Volume 2  

Science Conference Proceedings (OSTI)

The three-volume Ductile Fracture Handbook provides the structural analyst with computational methods for evaluating the integrity of flawed structures that are fabricated from ductile materials or have loads that may produce significant plasticity, specifically easy-to-use fracture mechanics solutions for a wide range of problems dealing with cylinders subjected to several types of elastic-plastic loading. Volume 2 presents new solutions and significant expansion of previous solutions, typically in the ...

1990-09-01T23:59:59.000Z

191

Ductile Fracture Handbook: Volume 3  

Science Conference Proceedings (OSTI)

The three-volume Ductile Fracture Handbook provides the structural analyst with computational methods for evaluating the integrity of flawed structures that are fabricated from ductile materials or have loads that may produce significant plasticity, specifically easy-to-use fracture mechanics solutions for a wide range of problems dealing with cylinders subjected to several types of elastic-plastic loading. Volume 3 presents solutions for axial part-throughwall cracks, cracks in elbows, tees, and nozzles...

1990-09-01T23:59:59.000Z

192

Tritium Effects on Fracture Toughness of Stainless Steel Weldments  

DOE Green Energy (OSTI)

The effects of tritium on the fracture toughness properties of Type 304L and Type 21-6-9 stainless steel weldments were measured. Weldments were tritium-charged-and-aged and then tested in order to measure the effect of the increasing decay helium content on toughness. The results were compared to uncharged and hydrogen-charged samples. For unexposed weldments having 8-12 volume percent retained delta ferrite, fracture toughness was higher than base metal toughness. At higher levels of weld ferrite, the fracture toughness decreased to values below that of the base metal. Hydrogen-charged and tritium-charged weldments had lower toughness values than similarly charged base metals and toughness decreased further with increasing weld ferrite content. The effect of decay helium content was inconclusive because of tritium off-gassing losses during handling, storage and testing. Fracture modes were dominated by the dimpled rupture process in unexposed weldments. In hydrogen and tritium-exposed weldments, the fracture modes depended on the weld ferrite content. At high ferrite contents, hydrogen-induced transgranular fracture of the weld ferrite phase was observed.

MORGAN, MICHAEL; CHAPMAN, G. K.; TOSTEN, M. H.; WEST, S. L.

2005-05-12T23:59:59.000Z

193

Boiling radial flow in fractures of varying wall porosity  

DOE Green Energy (OSTI)

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

Barnitt, Robb Allan

2000-06-01T23:59:59.000Z

194

Development, setup and testing of a dynamic hydraulic fracture conductivity apparatus  

E-Print Network (OSTI)

One of the most critical parameters in the success of a hydraulic fracturing treatment is to have sufficiently high fracture conductivity. Unbroken polymers can cause permeability impairment in the proppant pack and/or in the matrix along the fracture face. The objectives of this research project were to design and set up an experimental apparatus for dynamic fracture conductivity testing and to create a fracture conductivity test workflow standard. This entirely new dynamic fracture conductivity measurement will be used to perform extensive experiments to study fracturing fluid cleanup characteristics and investigate damage resulting from unbroken polymer gel in the proppant pack. The dynamic fracture conductivity experiment comprises two parts: pumping fracturing fluid into the cell and measuring proppant pack conductivity. I carefully designed the hydraulic fracturing laboratory to provide appropriate scaling of the field conditions experimentally. The specifications for each apparatus were carefully considered with flexibility for further studies and the capability of each apparatus was defined. I generated comprehensive experimental procedures for each experiment stage. By following the procedure, the experiment can run smoothly. Most of dry runs and experiments performed with sandstone were successful.

Pongthunya, Potcharaporn

2007-08-01T23:59:59.000Z

195

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

Open Energy Info (EERE)

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

196

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

Science Conference Proceedings (OSTI)

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

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

1993-01-01T23:59:59.000Z

197

Economic Recovery of Oil Trapped at Fan Margins Using Hig Angle Wells Multiple Hydraulic Fractures  

Science Conference Proceedings (OSTI)

The Yowlumne field is a giant field in the southern San Joaquin basin, Kern County, California. It is a deep (13,000 ft) waterflood operation that produces from the Miocene- aged Stevens Sand. The reservoir is interpreted as a layered, fan-shaped, prograding turbidite complex containing several lobe-shaped sand bodies that represent distinct flow units. A high ultimate recovery factor is expected, yet significant quantities of undrained oil remain at the fan margins. The fan margins are not economic to develop using vertical wells because of thinning pay, deteriorating rock quality, and depth. This project attempts to demonstrate the effectiveness of exploiting the northeast distal fan margin through the use of a high- angle well completed with multiple hydraulic- fracture treatments. A high-angle well offers greater pay exposure than can be achieved with a vertical well. Hydraulic-fracture treatments will establish vertical communication between thin interbedded layers and the wellbore. The equivalent production rate and reserves of three vertical wells are anticipated at a cost of approximately two vertical wells. The near-horizontal well penetrated the Yowlumne sand; a Stevens sand equivalent, in the distal fan margin in the northeast area of the field. The well was drilled in a predominately westerly direction towards the interior of the field, in the direction of improving rock quality. Drilling and completion operations proved to be very challenging, leading to a number of adjustments to original plans. Hole conditions resulted in obtaining less core material than desired and setting intermediate casing 1200 ft too high. The 7 in. production liner stuck 1000 ft off bottom, requiring a 5 in. liner to be run the rest of the way. The cement job on the 5 in. liner resulted in a very poor bond, which precluded one of three hydraulic fracture treatments originally planned for the well. Openhole logs confirmed most expectations going into the project about basic rock properties: the formation was shaly with low porosities, and water saturations were in line with expectations, including the presence of some intervals swept out by the waterflood. High water saturations at the bottom of the well eliminated one of the originally planned hydraulic fracture treatments. Although porosities proved to be low, they were more uniform across the formation than expected. Permeabilities of the various intervals continue to be evaluated, but appear to be better than expected from the porosity log model derived in Budget Period One. The well was perforated in all pay sections behind the 5 in. liner. Production rates and phases agree nicely with log calculations, fractional flow calculations, and an analytical technique used to predict the rate performance of the well.

Laue, M.L.

1997-11-21T23:59:59.000Z

198

Numerical Modeling of Fractured Shale-Gas and Tight-Gas Reservoirs Using Unstructured Grids  

E-Print Network (OSTI)

Various models featuring horizontal wells with multiple induced fractures have been proposed to characterize flow behavior over time in tight gas and shale gas systems. Currently, there is little consensus regarding the effects of non-ideal fracture geometries and coupled primary-secondary fracture interactions on reservoir performance in these unconventional gas reservoirs. This thesis provides a grid construction tool to generate high-resolution unstructured meshes using Voronoi grids, which provides the flexibility required to accurately represent complex geologic domains and fractures in three dimensions. Using these Voronoi grids, the interaction between propped hydraulic fractures and secondary "stress-release" fractures were evaluated. Additionally, various primary fracture configurations were examined, where the fractures may be non-planar or non-orthogonal. For this study, a numerical model was developed to assess the potential performance of tight gas and shale gas reservoirs. These simulations utilized up to a half-million grid-blocks and consider a period of up to 3,000 years in some cases. The aim is to provide very high-definition reference numerical solutions that will exhibit virtually all flow regimes we can expect in these unconventional gas reservoirs. The simulation results are analyzed to identify production signatures and flow regimes using diagnostic plots, and these interpretations are confirmed using pressure maps where useful. The coupled primary-secondary fracture systems with the largest fracture surface areas are shown to give the highest production in the traditional "linear flow" regime (which occurs for very high conductivity vertical fracture cases). The non-ideal hydraulic fracture geometries are shown to yield progressively lower production as the angularity of these fractures increases. Hence, to design optimum fracture completions, we should endeavor to keep the fractures as orthogonal to the horizontal well as possible. This work expands the current understanding of flow behavior in fractured tight-gas and shale-gas systems and may be used to optimize fracture and completion design, to validate analytical models and to facilitate more accurate reserves estimation.

Olorode, Olufemi Morounfopefoluwa

2011-12-01T23:59:59.000Z

199

Design and Implementation of Energized Fracture Treatment in Tight Gas Sands  

SciTech Connect

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

200

IN SITU STRESS, FRACTURE AND FLUID FLOW ANALYSIS-EAST FLANK OF THE COSO  

Open Energy Info (EERE)

IN SITU STRESS, FRACTURE AND FLUID FLOW ANALYSIS-EAST FLANK OF THE COSO IN SITU STRESS, FRACTURE AND FLUID FLOW ANALYSIS-EAST FLANK OF THE COSO GEOTHERMAL FIELD Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: IN SITU STRESS, FRACTURE AND FLUID FLOW ANALYSIS-EAST FLANK OF THE COSO GEOTHERMAL FIELD Details Activities (1) Areas (1) Regions (0) Abstract: High rock temperatures, a high degree of fracturing, high tectonic stresses, and low permeability are the combination of qualities that define an ideal candidate-Enhanced Geothermal System (EGS) reservoir. The Coso Geothermal Field is an area where fluid temperatures exceeding 300°C have been measured at depths less than 10,000 feet and the reservoir is both highly fractured and tectonically stressed. Some of the wells within this portion of the reservoir are relatively impermeable,

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201

A Comprehensive Study Of Fracture Patterns And Densities In The Geysers  

Open Energy Info (EERE)

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

202

A Numerical Algorithm for Fluid Flow in 3D Naturally Fractured Porous Media  

E-Print Network (OSTI)

Fluid flow in three-dimensional (3D) fractured porous media is considered. The governing system of partial differential equations consists of two subsystems -- one describing the flow in the fractures, and the other describing the flow in the matrix blocks. In this paper, wedevelop an efficient algorithm for the numerical solution of the problem. An operator splitting technique is employed, as a part of the time-stepping procedure, to decouple the system into easy subsystems. The fracture concentration equation is discretized by the modified method of characteristics (MMOC) in time due to high velocityin the fractures and bytheRaviart-Thomas-Nedelec mixed method of index zero (RTN0) in space. The matrix concentration equation is discretized byabackward Euler scheme and the linear finite element method. The pressure equation is approximated byRTN0 and the linear Galerkin method for the fractures and the matrix blocks, respectively. For the fracture system, a domain decomposition (DD) it...

Seongjai Kim

2000-01-01T23:59:59.000Z

203

Gradient effects on the fracture of inhomogeneous materials  

SciTech Connect

Functionally Graded Materials (FGMs) have a spatial variation in physical properties that can be tailored to meet the needs of a specific application and/or to minimize internal stresses arising from thermal and elastic mismatch. Modeling these materials as inhomogeneous continua allows assessment of the role of the gradient without requiring detailed knowledge of the microstructure. Motivated by the relative difficulty of obtaining analytical solutions to boundary value problems for FGMs, an accurate finite-element code is developed for obtaining numerical planar and axisymmetric linear thermoelastic solutions. In addition an approximate analytical technique for mapping homogeneous-modulus solutions to those for FGMs is assessed and classes of problems to which it applies accurately are identified. The fracture mechanics analysis of FGMs can be characterized by the classic stress intensities, KI and KII, but there has been scarce progress in understanding the role of the modulus gradient in determining fracture initiation and propagation. To address this question, a statistical fracture model is used to correlate near-tip stresses with brittle fracture initiation behavior. This describes the behavior of a material experiencing fracture initiation away from the crack tip. Widely dispersed zones of fracture initiation sites are expected. Finite-length kinks are analyzed to describe the crack path for continuous crack growth. For kink lengths much shorter than the gradient dimension, a parallel stress term describes the deviation of the kinking angle from that for homogeneous materials. For longer kinks there is a divergence of the kink angle predicted by the maximum energy release rate and the pure opening mode criteria.

Becker, T.L.

2000-05-01T23:59:59.000Z

204

Geothermal fracture stimulation technology. Volume III. Geothermal fracture fluids  

DOE Green Energy (OSTI)

A detailed study of all available and experimental frac fluid systems is presented. They have been examined and tested for physical properties that are important in the stimulation of hot water geothermal wells. These fluids consist of water-based systems containing high molecular weight polymers in the uncrosslinked and crosslinked state. The results of fluid testing for many systems are summarized specifically at geothermal conditions or until breakdown occurs. Some of the standard tests are ambient viscosity, static aging, high temperature viscosity, fluid-loss testing, and falling ball viscosity at elevated temperatures and pressures. Results of these tests show that unalterable breakdown of the polymer solutions begins above 300/sup 0/F. This continues at higher temperatures with time even if stabilizers or other high temperature additives are included.

Not Available

1981-01-01T23:59:59.000Z

205

A physically based numerical approach for modeling fracture-matrix interaction in fractured reservoirs  

E-Print Network (OSTI)

modeling fluid and heat flow in fractured porous media, Soc.flow through unsaturated fractured porous media, Proceedings of the Second International Symposium on Dynamics of Fluids

Wu, Yu-Shu; Pruess, Karsten

2004-01-01T23:59:59.000Z

206

A Physically Based Approach for Modeling Multiphase Fracture-Matrix Interaction in Fractured Porous Media  

E-Print Network (OSTI)

modeling fluid and heat flow in fractured porous media, Soc.flow through unsaturated fractured porous media, Proceedings of the Second International Symposium on Dynamics of Fluids

Wu, Yu-Shu; Pan, Lehua; Pruess, Karsten

2004-01-01T23:59:59.000Z

207

The Essential Work of Fracture Method Applied to Mode II Interlaminar Fracture in Fiber Reinforced Polymers.  

E-Print Network (OSTI)

??This thesis presents a new method for determining mode II interlaminar fracture toughness in fiber reinforced polymers (FRP) using the essential work of fracture (EWF)… (more)

McKinney, Scott D

2013-01-01T23:59:59.000Z

208

Hydraulic fracture optimization using hydraulic fracture and reservoir modeling in the Piceance Basin, Colorado.  

E-Print Network (OSTI)

??Hydraulic fracturing is an important stimulation method for producing unconventional gas reserves. Natural fractures are present in many low-permeability gas environments and often provide important… (more)

Reynolds, Harris Allen

2012-01-01T23:59:59.000Z

209

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

Science Conference Proceedings (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

210

Finite element modeling and experimental study of brittle fracture in tempered martensitic steels for thermonuclear fusion applications.  

E-Print Network (OSTI)

??In this work we have studied brittle fracture in high-chromium reduced activation tempered martensitic steels foreseen as structural materials for thermonuclear fusion reactors. Developing the… (more)

Mueller, Pablo Federico

2009-01-01T23:59:59.000Z

211

TMS Continuing Education Page  

Science Conference Proceedings (OSTI)

Education Development. If you are interested in developing a continuing education activity, please review the specific course options and requirements below.

212

Continuous Sludge Leaching  

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

Continuous Sludge Leaching Reid Peterson and Renee Russell - Battelle Pacific Northwest Division Terry Sams and Bill Brasel - Parsons 2 What is CSL? * Process diagram * Full scale...

213

Nonisothermal injection tests in fractured reservoirs  

DOE Green Energy (OSTI)

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

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

1985-01-01T23:59:59.000Z

214

Monitoring hydraulic fracture growth: Laboratory experiments  

Science Conference Proceedings (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

215

High-Resolution Analysis of Frontal Fracture  

Science Conference Proceedings (OSTI)

A mesoscale array of dropwindsondes, released in a small rapidly deepening frontal wave cyclone in the eastern North Atlantic during the FRONTS 92 experiment, has been assimilated into a 17-km-grid mesoscale model nested within the Meteorological ...

K. A. Browning; S. P. Ballard; C. S. A. Davitt

1997-06-01T23:59:59.000Z

216

Reinjection Model Studies in Fractured and Homogeneous Geothermal Systems  

DOE Green Energy (OSTI)

Reinjection of geothermal waste waters has become an important topic of interest for industry as well as for research. The environmental concerns due to chemical composition of geothermal waste waters had urged the industry to dispose it underground. In several field applications no interference due to thermal front breakthrough was observed on the other hand some cases are reported where reinjection had caused severe declines in energy production due to unexpected breakthrough of injected water. Several analytical and numerical studies are available where the effect of fractures on the movement of thermal front are discussed. It was shown that when the conduction heat transfer from matrix to fracture dominates, retardation of the thermal front movement will be observed. Bodvarsson and Pruess considered the above problem in a five-spot well pattern. They observed as the amount of fluid injected reaches the amount produced, the long-term energy output of the system increases. Pruess in his study compares the behavior of porous medium and fractured medium in terms of pressure decline due to production. Temperature and pressure profiles are presented between an injector and a producer where heating of the injected water in porous medium and in fractured medium with small fracture spacing was high compared to a larger fracture spacing. Such observations from the numerical studies were checked against some limited field examples. However understanding of the injection effects in fractured reservoirs is limited. This work presents the results of laboratory experiments where effects of reinjection on temperature and pressure behavior of a porous medium and a fractured medium were investigated. The porous medium was a crushed limestone pack, with 10 mm average particle size, packed in a 3-D box model where injection and production ports are located on the diagonal ends simulating a five-spot pattern. The fractured medium was made from uniformly cut marble blocks packed in such a way to permit uniform fracture geometry. The pressure and temperature response of both models are analyzed as a function of (1) depth of injection and production; and (2) injection rate where 20 C injection water is injected into 110 C reservoir.

Okandan, E.; Hosca, H.

1986-01-21T23:59:59.000Z

217

Hydraulic Fracturing | Open Energy Information  

Open Energy Info (EERE)

Hydraulic Fracturing Hydraulic Fracturing Jump to: navigation, search More info on OpenEI Oil and Gas Gateway Federal Environmental Statues Federal Oil and Gas Statutes Oil and Gas Companies United States Oil and Gas Boards International Oil and Gas Boards Other Information Fracking Regulations by State Wells by State Fracking Chemicals Groundwater Protection Related Reports A Perspective on Health and Natural Gas Operations: A Report for Denton City Council Just the Fracking Facts The Politics of 'Fracking': Regulating Natural Gas Drilling Practices in Colorado and Texas Addressing the Environmental Risks from Shale Gas Development Water Management Technologies Used by Marcellus Shale Gas Producers Methane contamination of drinking wateraccompanying gas-well drilling and hydraulic fracturing

218

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

219

Continuations and Web Servers  

Science Conference Proceedings (OSTI)

Programming web applications in direct style with the help of continuations is a much simpler, safer, modular and better-performing technology than the current dominating "page-centric" technology combining CGI scripts, active pages or servlets. This ... Keywords: WWW, continuations, hypertext, scheme

Christian Queinnec

2004-12-01T23:59:59.000Z

220

Continuations and transducer composition  

Science Conference Proceedings (OSTI)

On-line transducers are an important class of computational agent; we construct and compose together many software systems using them, such as stream processors, layered network protocols, DSP networks and graphics pipelines. We show an interesting use ... Keywords: calculus, continuation-passing style (CPS), continuations, coroutines, flow analysis, functional languages, fusion, lambda, language design, program analysis, stream processing

Olin Shivers; Matthew Might

2006-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "highly fractured continuous" 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

Identification of modes of fracture in a 2618-T6 aluminum alloy using stereophotogrammetry  

Science Conference Proceedings (OSTI)

The identification and the development of a quantification technique of the modes of fracture in fatigue fracture surfaces of a 2618-T6 aluminum alloy were developed during this research. Fatigue tests at room and high temperature (230 Degree-Sign C) were carried out to be able to compare the microscopic fractographic features developed by this material under these testing conditions. The overall observations by scanning electron microscopy (SEM) of the fracture surfaces showed a mixture of transgranular and ductile intergranular fracture. The ductile intergranular fracture contribution appears to be more significant at room temperature than at 230 Degree-Sign C. A quantitative methodology was developed to identify and to measure the contribution of these microscopic fractographic features. The technique consisted of a combination of stereophotogrammetry and image analysis. Stereo-pairs were randomly taken along the crack paths and were then analyzed using the profile module of MeX software. The analysis involved the 3-D surface reconstruction, the trace of primary profile lines in both vertical and horizontal directions within the stereo-pair area, the measurements of the contribution of the modes of fracture in each profile, and finally, the calculation of the average contribution in each stereo-pair. The technique results confirmed a higher contribution of ductile intergranular fracture at room temperature than at 230 Degree-Sign C. Moreover, there was no indication of a direct relationship between this contribution and the strain amplitudes range applied during the fatigue testing. - Highlights: Black-Right-Pointing-Pointer Stereophotogrammetry and image analysis as a measuring tool of modes of fracture in fatigue fracture surfaces. Black-Right-Pointing-Pointer A mixture of ductile intergranular and transgranular fracture was identified at room temperature and 230 Degree-Sign C testing. Black-Right-Pointing-Pointer Development of a quantitative methodology to obtain the percentage of modes of fracture within the fracture surface.

Salas Zamarripa, A., E-mail: a.salaszamarripa@gmail.com [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon. Av. Universidad S/N, Ciudad Universitaria, C.P. 66451, Apartado Postal 076 Suc. 'F' San Nicolas de los Garza, N.L. (Mexico); Pinna, C.; Brown, M.W. [Department of Mechanical Engineering, University of Sheffield. Sir Frederick Mappin Building, Mappin Street, Sheffield, S1 3JD (United Kingdom); Mata, M.P. Guerrero; Morales, M. Castillo; Beber-Solano, T.P. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon. Av. Universidad S/N, Ciudad Universitaria, C.P. 66451, Apartado Postal 076 Suc. 'F' San Nicolas de los Garza, N.L. (Mexico)

2011-12-15T23:59:59.000Z

222

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

SciTech Connect

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

Gary Mavko

2000-10-01T23:59:59.000Z

223

Sealed glass coating of high temperature ceramic superconductors  

DOE Patents (OSTI)

A method and article of manufacture of a lead oxide based glass coating on a high temperature superconductor. The method includes preparing a dispersion of glass powders in a solution, applying the dispersion to the superconductor, drying the dispersion before applying another coating and heating the glass powder dispersion at temperatures below oxygen diffusion onset and above the glass melting point to form a continuous glass coating on the superconductor to establish compressive stresses which enhance the fracture strength of the superconductor.

Wu, Weite (Tainan, TW); Chu, Cha Y. (Garnerville, NY); Goretta, Kenneth C. (Downers Grove, IL); Routbort, Jules L. (Darien, IL)

1995-01-01T23:59:59.000Z

224

TRITIUM AGING EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF FORGED STAINLESS STEEL  

DOE Green Energy (OSTI)

The fracture toughness properties of Type 21-6-9 stainless steel were measured for forgings in the unexposed, hydrogen-exposed, and tritium-exposed-and-aged conditions. Fracture toughness samples were cut from conventionally-forged and high-energy-rate-forged forward-extruded cylinders and mechanically tested at room temperature using ASTM fracture-toughness testing procedures. Some of the samples were exposed to either hydrogen or tritium gas (340 MPa, 623 K) prior to testing. Tritium-exposed samples were aged for up to seven years and tested periodically in order to measure the effect on fracture toughness of {sup 3}He from radioactive tritium decay. The results show that hydrogen-exposed and tritium-exposed samples had lower fracture- toughness values than unexposed samples and that fracture toughness decreased with increasing decay {sup 3}He content. Forged steels were more resistant to the embrittling effects of tritium and decay {sup 3}He than annealed steels, although their fracture-toughness properties depended on the degree of sensitization that occurred during processing. The fracture process was dominated by microvoid nucleation, growth and coalescence; however, the size and spacing of microvoids on the fracture surfaces were affected by hydrogen and tritium with the lowest-toughness samples having the smallest microvoids and finest spacing.

Morgan, M

2008-04-14T23:59:59.000Z

225

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

226

Effects of dry fractures on matrix diffusion in unsaturated fractured rocks  

E-Print Network (OSTI)

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

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

2002-01-01T23:59:59.000Z

227

Dissipative particle dynamics simulation of fluid motion through an unsaturated fracture and fracture junction  

Science Conference Proceedings (OSTI)

Multiphase fluid motion in unsaturated fractures and fracture networks involves complicated fluid dynamics, which is difficult to model using grid-based continuum methods. In this paper, the application of dissipative particle dynamics (DPD), a relatively ... Keywords: Dissipative particle dynamics (DPD), Fracture, Fracture flow, Smoothed particle hydrodynamics (SPH), Weight functions

Moubin Liu; Paul Meakin; Hai Huang

2007-03-01T23:59:59.000Z

228

Spalling and Dynamic Fracture  

Science Conference Proceedings (OSTI)

Mar 1, 2011 ... Laser-driven plate impact experiments were conducted at low .... large, light- weight (usually Al) projectiles hundreds of miles using a high ...

229

Summary of Linear Elastic Fracture Mechanics Concepts  

Science Conference Proceedings (OSTI)

...in this Volume."Stress Intensity Factors"A brief summary of linear elastic fracture mechanics (LEFM) concepts

230

Development of a fixation device for robot assisted fracture reduction of femoral shaft fractures: A biomechanical study  

Science Conference Proceedings (OSTI)

Robot assisted fracture reduction of femoral shaft fractures provides precise alignment while reducing the amount of intraoperative imaging. The connection between the robot and the fracture fragment should allow conventional intramedullary nailing, ... Keywords: Robot, femur shaft, fracture reduction, interface

T. S. Weber-Spickschen; M. Oszwald; R. Westphal; C. Krettek; F. Wahl; T. Gosling

2010-08-01T23:59:59.000Z

231

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

Science Conference Proceedings (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

232

Fracturing fluid characterization: State-of-the-art facility and advanced technology  

Science Conference Proceedings (OSTI)

The petroleum industry has used hydraulic fracturing technique to stimulate low and high permeability oil and gas reservoirs to enhance their potential recoveries. Nevertheless, the design and implementation of a scientifically and economically sound fracturing job, due to the lack of knowledge of theological behavior of hydraulic fracturing fluids under field conditions, remains a challenge. Furthermore, as often the case, the current level of technical knowledge with research institutes, service companies, and operators does not translate to field applications. One of the principal reasons for this technology gap, is the lack of understanding of the theological behavior of hydraulic fracturing fluids under field conditions, which primarily relates to the limitations in scaling down the field conditions to the laboratory. The Fracturing Fluid Characterization Facility (FFCF) project was therefore, proposed with the intent of providing the industry with a better understanding of the behavior of these fracturing fluids and their proppant transport characteristics under downhole fracture condition. At the FFCF, a fully operational High Pressure Simulator (HPS), as seen in Figure 1, constitutes a vertical, variable width, parallel plate flow apparatus and is capable of operating at elevated temperatures (up to 2500F) and pressures (up to 1200 psi). The HPS simulates, to the maximum degree practical, all conditions experienced by a fracturing fluid from its formulation on the surface, its flow down the wellbore, through perforations, its injection into the fracture, and its leakage into the rock formation (Figure 1). Together with the onsite auxiliary equipment (Figure 2), such as Mixing and Pumping System, Pre-conditioning System, Data Acquisition System, and Rheology Measuring System (Figure 2), the HPS is the most advanced fracture simulator available to conduct research, mimicking field conditions, in the following areas: Rheology Characterization of Fracturing Fluids, Proppant Transport Simulations, Proppant Transport Measurements, Perforation Pressure Loss, Coiled Tubing Friction Loss, Dynamic Fluid Loss, and Heat Transfer Characterizations of Polymer Solutions.

Shah, S., Asadi, M.,

1997-10-01T23:59:59.000Z

233

Injection and energy recovery in fractured geothermal reservoirs  

DOE Green Energy (OSTI)

Numerical studies of the effects of injection on the behavior of production wells completed in fractured two-phase geothermal reservoirs are presented. In these studies the multiple-interacting-continua (MINC) method is employed for the modeling of idealized fractured reservoirs. Simulations are carried out for a five-spot well pattern with various well spacings, fracture spacings, and injection fractions. The production rates from the wells are calculated using a deliverability model. The results of the studies show that injection into two-phase fractured reservoirs increases flow rates and decreases enthalpies of producing wells. These two effects offset each other so that injection tends to have small effects on the usable energy output of production wells in the short term. However, if a sufficiently large fraction of the produced fluids is injected, the fracture system may become liquid-filled and an increased steam rate is obtained. Our studies show that injection greatly increases the long-term energy output from wells, as it helps extract heat from the resrvoir rocks. If a high fraction of the produced fluids is injected, the ultimate energy recovery will increase manyfold.

Bodvarsson, G.S.; Pruess, K.; O'Sullivan, M.J.

1983-01-01T23:59:59.000Z

234

Determination of the effect of formation water on fracture-fluid cleanup  

SciTech Connect

Understanding hydraulic-fracture cleanup is essential for improving well stimulation. Residual gel damages fracture conductivity, shortens effective fracture half-length, and limits well productivity. The drive to develop fluids, additives, and procedures that minimize this damage continues to be a dominant theme in fracture-fluid-development programs. Fracture cleanup is a complex problem, and many parameters (e.g., fluid system, job design, flowback procedure, and reservoir conditions) can influence polymer and fluid recovery efficiencies. Often, specific products and methods that work well in one reservoir have little effect in another. Systematic analysis of fluid and polymer returns after a treatment is completed is the only way to quantify fracture cleanup. This is referred to as flowback analysis. This paper discusses a flowback-analysis field study on large hydraulic-fracturing treatments in the Taylor zone of the Cotton Valley formation in east Texas. This is a low-permeability (approximately 0.01 md) tight gas formation. It is a heterogeneous zone with layers of productive sandstone interspersed with relatively impermeable layers of shale. A typical well in this field initially produces approximately 0.75 to 1.3 MMcf/D gas and 35 to 40 bbl of water/MMcf of gas. The returns from 10 wells in this field were analyzed thoroughly.

NONE

1998-03-01T23:59:59.000Z

235

Fractured shale reservoirs: Towards a realistic model  

Science Conference Proceedings (OSTI)

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

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

1996-09-01T23:59:59.000Z

236

Ozone generation by rock fracture: Earthquake early warning?  

Science Conference Proceedings (OSTI)

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

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

2011-11-14T23:59:59.000Z

237

Using Chemicals to Optimize Conformance Control in Fractured Reservoirs  

SciTech Connect

This report describes work performed during the first year of the project, ''Using Chemicals to Optimize Conformance Control in Fractured Reservoirs.'' This research project has three objectives. The first objective is to develop a capability to predict and optimize the ability of gels to reduce permeability to water more than that to oil or gas. The second objective is to develop procedures for optimizing blocking agent placement in wells where hydraulic fractures cause channeling problems. The third objective is to develop procedures to optimize blocking agent placement in naturally fractured reservoirs. This research project consists of three tasks, each of which addresses one of the above objectives. Our work is directed at both injection wells and production wells and at vertical, horizontal, and highly deviated wells.

Seright, Randall S.; Liang, Jenn-Tai; Schrader, Richard; Hagstrom II, John; Liu, Jin; Wavrik, Kathryn

1999-09-27T23:59:59.000Z

238

Dynamic testing and characterization of pre-fractured ceramic  

SciTech Connect

Nearly all of the mechanical behavior studies of armor ceramics, to date, havc involved the characterization and testing of pristine ceramic material. However, balhstic impact causes a strong shock front to propagate rapidly through the ceramic before much penetration can occur. A strong shock wave can result in localized compressive failure and fragmentation of the ceramic before its amplitude is amnuated below the compressive strength of the ceramic. Goals of this effort were to creatc shock-fractured ceramic using test assemblies which maintain the intergranular coupling and high density of the ceramic, characterize the extent and homogeneity of the fragmentation and dilatation of the ceramic, and test the compressive dynamic behavior of the shock-fractured ceramic under conditions of confining pressure. This effort will provide data to support models of the penetration resistance of fractured ceramics including degraded moduli, failure strength-strain, and post-failure characterization of the erosive properties of comminuted ceramic and penetratot materials.

Zurek, A.K.; Hunter, D.A.

1993-01-01T23:59:59.000Z

239

Dynamic testing and characterization of pre-fractured ceramic  

Science Conference Proceedings (OSTI)

Nearly all of the mechanical behavior studies of armor ceramics, to date, havc involved the characterization and testing of pristine ceramic material. However, balhstic impact causes a strong shock front to propagate rapidly through the ceramic before much penetration can occur. A strong shock wave can result in localized compressive failure and fragmentation of the ceramic before its amplitude is amnuated below the compressive strength of the ceramic. Goals of this effort were to creatc shock-fractured ceramic using test assemblies which maintain the intergranular coupling and high density of the ceramic, characterize the extent and homogeneity of the fragmentation and dilatation of the ceramic, and test the compressive dynamic behavior of the shock-fractured ceramic under conditions of confining pressure. This effort will provide data to support models of the penetration resistance of fractured ceramics including degraded moduli, failure strength-strain, and post-failure characterization of the erosive properties of comminuted ceramic and penetratot materials.

Zurek, A.K.; Hunter, D.A.

1993-07-01T23:59:59.000Z

240

Continuous sulfur removal process  

DOE Patents (OSTI)

A continuous process for the removal of hydrogen sulfide from a gas stream using a membrane comprising a metal oxide deposited on a porous support is disclosed. 4 figures.

Jalan, V.; Ryu, J.

1994-04-26T23:59:59.000Z

Note: This page contains sample records for the topic "highly fractured continuous" 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

Business Continuity Planning  

Science Conference Proceedings (OSTI)

This article considers various strategies for protecting an organisation from both natural and man-made disasters. The differences between business continuity planning, and disaster recovery planning are recognised. © 1997 John Wiley & Sons, ...

Martin Nemzow

1997-07-01T23:59:59.000Z

242

TRITIUM AGING EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF STAINLESS STEEL BASE METAL AND WELDS  

DOE Green Energy (OSTI)

Tritium reservoirs are constructed from welded stainless steel forgings. While these steels are highly resistant to the embrittling effects of hydrogen isotopes and helium from tritium decay; they are not immune. Tritium embrittlement is an enhanced form of hydrogen embrittlement because of the presence of helium-3 from tritium decay which nucleates as nanometer-sized bubbles on dislocations, grain boundaries, and other microstructural defects. Steels with decay helium bubble microstructures are hardened and less able to deform plastically and become more susceptible to embrittlement by hydrogen and its isotopes. Ductility, elongation-to-failure, and fracture toughness are reduced by exposures to tritium and the reductions increase with time as helium-3 builds into the material from tritium permeation and radioactive decay. Material and forging specifications have been developed for optimal material compatibility with tritium. These specifications cover composition, mechanical properties, and select microstructural characteristics like grain size, flow-line orientation, inclusion content, and ferrite distribution. For many years, the forming process of choice for reservoir manufacturing was high-energy-rate forging (HERF), principally because the DOE forging facility owned only HERF hammers. Today, some reservoir forgings are being made that use a conventional, more common process known as press forging (PF or CF). One of the chief differences between the two forging processes is strain rate: Conventional hydraulic or mechanical forging presses deform the metal at 4-8 ft/s, about ten-fold slower than the HERF process. The material specifications continue to provide successful stockpile performance by ensuring that the two forging processes produce similar reservoir microstructures. While long-term life storage tests have demonstrated the general tritium compatibility of tritium reservoirs, fracture-toughness properties of both conventionally forged and high-energy-rate forged are needed for designing and establishing longer tritium-reservoir lifetimes, ranking materials, and, potentially, for qualifying new forging vendors or processes. Measurements on the effects of tritium and decay helium on the fracture toughness properties of CF stainless steels having similar composition, grain size, and mechanical properties to previously studied HERF steels are needed and have not been conducted until now. The compatibility of stainless steel welds with tritium represents another concern for long-term reservoir performance. Weldments have not been well-characterized with respect to tritium embrittlement, although a recent study was completed on the effect of tritium and decay helium on the fracture toughness properties of Type 304L weldments. This study expands the characterization of weldments through measurements of tritium and decay helium effects on the fracture toughness properties of Type 21-6-9 stainless steel. The purpose of this study was to measure and compare the fracture toughness properties of Type 21-6-9 stainless steel for conventional forgings and weldments in the non-charged, hydrogen-charged and tritium-charged-and-aged conditions.

Morgan, M.

2009-07-30T23:59:59.000Z

243

Symmetric continued fractions  

SciTech Connect

Explicit formulae for continued fractions with symmetric patterns in their partial quotients are constructed in the field of formal power series. Similar to the work of Cohn in 1996, which generalized the so-called folding lemma to {kappa}-fold symmetry, the notion of {kappa}-duplicating symmetric continued fractions is investigated using a modification of the 1995 technique due to Clemens, Merrill and Roeder.

Panprasitwech, Oranit [Department of Mathematics, Faculty of Science, King Mongkut' s University of Technology Thonburi, Bangkok 10140 (Thailand); Laohakosol, Vichian [Department of Mathematics, Faculty of Science, Kasetsart University, Bangkok 10900 (Thailand); Chaichana, Tuangrat [Department of Mathematics, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand)

2010-11-11T23:59:59.000Z

244

Geomechanical Simulation of Fluid-Driven Fractures  

SciTech Connect

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

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

2012-11-30T23:59:59.000Z

245

Method for enhancement of sequential hydraulic fracturing using control pulse fracturing  

Science Conference Proceedings (OSTI)

A method is described for creating multiple sequential hydraulic fractures via hydraulic fracturing combined with controlled pulse fracturing where two wells are utilized comprising: (a) drilling and completing a first and second well so that the wells will be in fluid communication with each other after subsequent fracturing in each well; (b) creating more than two simultaneous multiple vertical fractures via a controlled pulse fracturing method in the second well; (c) thereafter hydraulically fracturing the reservoir via the first well thereby creating fractures in the reservoir and afterwards shutting-in the first well without any induced pressure; (d) applying thereafter hydraulic pressure to the reservoir via the second well in an amount sufficient to fracture the reservoir thereby forming a first hydraulic fracture perpendicular to the least principal in-situ stress; (e) maintaining the hydraulic pressure on the reservoir while pumping via the second well alternate slugs of a thin-fluid spacer and a temporary blocking agent having a proppant therein whereupon a second hydraulic fracture is initiated; (f) maintaining the hydraulic pressure on the second well while pumping alternate slugs of spacer and blocking agent into the second hydraulic fracture thereby causing the second hydraulic fracture to propagate away from the first hydraulic fracture in step (e) in a curved trajectory which intersects a fracture created in the first well; (g) maintaining the hydraulic pressure while pumping as in step (f) whereupon another hydraulic fracture initiates causing another curved fracture trajectory to form and intersect the fracture created in the first well; and (h) repeated steps (f) and (g) until a desired number of hydraulic fractures are created which allows a substantial improvement in removing a natural resource from the reservoir.

Jennings, A.R. Jr.; Strubhar, M.K.

1993-07-20T23:59:59.000Z

246

Mapping acoustic emissions from hydraulic fracture treatments using coherent array processing: Concept  

DOE Green Energy (OSTI)

Hydraulic fracturing is a widely-used well completion technique for enhancing the recovery of gas and oil in low-permeability formations. Hydraulic fracturing consists of pumping fluids into a well under high pressure (1000--5000 psi) to wedge-open and extend a fracture into the producing formation. The fracture acts as a conduit for gas and oil to flow back to the well, significantly increasing communication with larger volumes of the producing formation. A considerable amount of research has been conducted on the use of acoustic (microseismic) emission to delineate fracture growth. The use of transient signals to map the location of discrete sites of emission along fractures has been the focus of most research on methods for delineating fractures. These methods depend upon timing the arrival of compressional (P) or shear (S) waves from discrete fracturing events at one or more clamped geophones in the treatment well or in adjacent monitoring wells. Using a propagation model, the arrival times are used to estimate the distance from each sensor to the fracturing event. Coherent processing methods appear to have sufficient resolution in the 75 to 200 Hz band to delineate the extent of fractures induced by hydraulic fracturing. The medium velocity structure must be known with a 10% accuracy or better and no major discontinuities should be undetected. For best results, the receiving array must be positioned directly opposite the perforations (same depths) at a horizontal range of 200 to 400 feet from the region to be imaged. Sources of acoustic emission may be detectable down to a single-sensor SNR of 0.25 or somewhat less. These conclusions are limited by the assumptions of this study: good coupling to the formation, acoustic propagation, and accurate knowledge of the velocity structure.

Harris, D.B.; Sherwood, R.J.; Jarpe, S.P.; Harben, P.E.

1991-09-01T23:59:59.000Z

247

RESEARCH PROGRAM ON FRACTURED PETROLEUM RESERVOIRS  

Science Conference Proceedings (OSTI)

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

Abbas Firoozabadi

2002-04-12T23:59:59.000Z

248

Surface Treatment of Carbon Fibers by Continuous Gaseous System  

SciTech Connect

The mechanical performance of carbon fiber-polymer composites strongly depends on interfacial adhesion, which is function of types of carbon fiber, surface chemistry, physical and chemical interactions, and mechanical interlocking. Untreated and unsized high strength carbon fibers were oxidized by continuous thermochemical and atmospheric plasma treatment. Surface properties were investigated before and after treatment (chemistry, topography), as well as their mechanical properties. X-ray photoelectron spectroscopy revealed a significant increase of the oxygen atomic content from 3% to around 20% and the analysis of the carbon peak showed that carboxylic acid functionalities and hydroxyl groups were generated. An observation of the fiber surface by scanning electron microscopy and atomic force microscopy did not show any dramatic change of the fiber morphology and surface topography. A Raman spectroscopy analysis exhibited that the weak boundary layers and debris remaining at the surface of untreated fibers were removed. No significant damage of the mechanical properties (tensile strength) was noticed. The influence of the changes of the surface properties on interfacial adhesion of carbon fiber-epoxy and -vinyl ester matrix was evaluated using 90 flexural and short beam shear tests with unidirectional coupons. A significant increase of the 90 flexural and short beam shear strength showed that the interfacial adhesion between carbon fibers and epoxy resins was improved. The observation of the fracture profile by scanning electron microcopy confirmed those results, as the rupture of the coupons after surface treatment was more cohesive.

Vautard, Frederic [ORNL; Paulauskas, Felix L [ORNL; Naskar, Amit K [ORNL; Warren, Charles David [ORNL; Meyer III, Harry M [ORNL; Ozcan, Soydan [ORNL

2011-01-01T23:59:59.000Z

249

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

250

Microseismic Tracer Particles for Hydraulic Fracturing  

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

Microseismic Tracer Particles for Hydraulic Fracturing Microseismic Tracer Particles for Hydraulic Fracturing Microseismic Tracer Particles for Hydraulic Fracturing Scientists at Los Alamos National Laboratory have developed a method by which microseismic events can be discriminated/detected 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 of oil and gas. July 3, 2013 Microseismic Tracer Particles for Hydraulic Fracturing Figure 1: A graph of ionic conductivity as a function of temperature for the anti-perovskite Li3OCl. Available for thumbnail of Feynman Center (505) 665-9090 Email Microseismic Tracer Particles for Hydraulic Fracturing Applications: Oil and gas production Geophysical exploration Benefits: Tracks the disposition of material in a hydraulic fracturing

251

Hydrodynamics of a vertical hydraulic fracture  

DOE Green Energy (OSTI)

We have developed a numerical algorithm, HUBBERT, to simulate the hydrodynamics of a propagating vertical, rectangular fracture in an elastic porous medium. Based on the IFD method, this algorithm assumes fracture geometry to be prescribed. The breakdown and the creation of the incipient fracture is carried out according to the Hubbert-Willis theory. The propagation of the fracture is based on the criterion provided by Griffith, based on energy considerations. The deformation properties of the open fracture are based on simple elasticity solutions. The fracture is assumed to have an elliptical shape to a distance equal to the fracture height, beyond which the shape is assumed to be parallel plate. A consequence of Griffith's criterion is that the fracture must propagate in discrete steps. The parametric studies carried out suggest that for a clear understanding of the hydrodynamics of the hydraulic fracture many hitherto unrecognized parameters must be better understood. Among these parameters one might mention, efficiency, aperture of the newly formed fracture, stiffness of the newly formed fracture, relation between fracture aperture and permeability, and well bore compliance. The results of the studies indicate that the patterns of pressure transients and the magnitudes of fracture length appear to conform to field observations. In particular, the discrete nature of fracture propagation as well as the relevant time scales of interest inferred from the present work seem to be corroborated by seismic monitoring in the field. The results suggest that the estimation of least principal stress can be reliably made either with shut in data or with reinjection data provided that injection rates are very small.

Narasimhan, T.N.

1987-03-24T23:59:59.000Z

252

Reservoir-scale fracture permeability in the Dixie Valley, Nevada, geothermal field  

Science Conference Proceedings (OSTI)

Wellbore image data recorded in six wells penetrating a geothermal reservoir associated with an active normal fault at Dixie Valley, Nevada, were used in conjunction with hydrologic tests and in situ stress measurements to investigate the relationship between reservoir productivity and the contemporary in situ stress field. The analysis of data from wells drilled into productive and non-productive segments of the Stillwater fault zone indicates that fractures must be both optimally oriented and critically stressed to have high measured permeabilities. Fracture permeability in all wells is dominated by a relatively small number of fractures oriented parallel to the local trend of the Stillwater Fault. Fracture geometry may also play a significant role in reservoir productivity. The well-developed populations of low angle fractures present in wells drilled into the producing segment of the fault are not present in the zone where production is not commercially viable.

Barton, C.A.; Zoback, M.D. [Stanford Univ., CA (United States). Dept. of Geophysics; Hickman, S. [Geological Survey, Menlo Park, CA (United States); Morin, R. [Geological Survey, Denver, CO (United States); Benoit, D. [Oxbow Geothermal Corp., Reno, NV (United States)

1998-08-01T23:59:59.000Z

253

Application of Liebowitz-Eftis nonlinear method to fracture control of welded structures  

Science Conference Proceedings (OSTI)

Fracture control of high toughness steels requires both crack initiation and propagation control. In ductile materials, crack propagation resistance plays a key role, but this quality is not readily definable by any of the existing testing standards. Liebowitz, Eftis et al proposed a comprehensive theoretical treatment applicable to ductile fracture. This was applied to a set of COD test data obtained from welds in high strength pipeline steels. Although more experimental work is required, the correlation between the COD results and the L-E analysis is excellent. This type of analysis may provide a basis for significant insight into ductile fracture toughness evaluation.

Shimizu, H.; Gibbon, W.M.; Lo, J.; Urednicek, M.

1983-05-01T23:59:59.000Z

254

Evaluation of fracturing results in deviated wellbores through on-site measurements  

SciTech Connect

Four adjacent oil wells in the Kuparuk River oil field, with deviated angles of 6{sup 0}5', 24{sup 0}6', 27{sup 0} and 36{sup 0}7' from the vertical at the perforations, were analyzed with prefracturing tests. The total fluid volume for these tests varied from 645 to 840 bbl(103 to 134 m/sup 3/) of either clean lease oil or water-based fracturing fluid at low to intermediate rates (up to 15bbl/min(2.4m/sup 3/)). These wells were subsequently fractured with proppant-laden fluid. A series of instantaneous shut-in pressures (ISIO's) was obtained for each well. ISIP's and fracturing pressures decreased with time in two of the four wells with a relatively high friction pressure at the end of the pumping. A radially propagating fracture from a point source of pressure explains this decreasing pressure with time. The elasticity theory predicts that a fracture in a deviated, cased wellbore should intersect the wellbore at one location. Only when the deviated wellbore azimuth is near that of the fracture orientation does the fracture sweep the entire perforated zone. This observation of the fracture orientation relative to the wellbore azimuth based on the pressure analysis is enhanced further by postfracture temperature surveys. It appears that only a relatively small volume of proppant could be displaced in a deviated wellbore. The degree of deviation, however, did not appear to be a major concern in the treatment of size.

Kim, C.M. (Halliburton Services, Duncan, OK (USA)); Champion, J.H. (Arco Alaska Inc. (US)); Cooper, G.D. (Guydon Software Services (US))

1989-08-01T23:59:59.000Z

255

Correlations to predict frictional pressure loss of hydraulic-fracturing slurry in coiled tubing  

Science Conference Proceedings (OSTI)

Compared with conventional-tubing fracturing, coiled-tubing (CT) fracturing has several advantages. CT fracturing has become an effective stimulation technique for multizone oil and gas wells. It is also an attractive production-enhancement method for multiseam coalbed-methane wells, and wells with bypassed zones. The excessive frictional pressure loss through CT has been a concern in fracturing. The small diameter of the string limits the cross-sectional area open to flow. Furthermore, the tubing curvature causes secondary flow and results in extra flow resistance. This increased frictional pressure loss results in high surface pumping pressure. The maximum possible pump rate and sand concentration, therefore, have to be reduced. To design a CT fracturing job properly, it is essential to predict the frictional pressure loss through the tubing accurately. This paper presents correlations for the prediction of frictional pressure loss of fracturing slurries in straight tubing and CT. They are developed on the basis of full-scale slurry-flow tests with 11/2-in. CT and slurries prepared with 35 lbm/1,000 gal of guar gel. The extensive experiments were conducted at the full-scale CT-flow test facility. The proposed correlations have been verified with the experimental data and actual field CT-fracturing data. Case studies of wells recently fractured are provided to demonstrate the application of the correlations. The correlations will be useful to the CT engineers in their hydraulics design calculations.

Shah, S.; Zhoi, Y.X.; Bailey, M.; Hernandez, J. [University of Oklahoma, Norman, OK (United States)

2009-08-15T23:59:59.000Z

256

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

E-Print Network (OSTI)

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

Michelet, Sophie

2006-01-01T23:59:59.000Z

257

4D imaging of fracturing in organic-rich shales during heating1 Maya Kobchenko1  

E-Print Network (OSTI)

1 4D imaging of fracturing in organic-rich shales during heating1 2 Maya Kobchenko1 , Hamed Panahi1-rich17 Green River shale. At about 350°C cracks nucleated in the sample, and as the temperature18 continued to increase, these cracks propagated parallel to shale bedding and coalesced, thus19 cutting

Paris-Sud XI, Université de

258

4D imaging of fracturing in organic-rich shales during heating Maya Kobchenko,1  

E-Print Network (OSTI)

4D imaging of fracturing in organic-rich shales during heating Maya Kobchenko,1 Hamed Panahi,1 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

Mazzini, Adriano

259

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

SciTech Connect

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

260

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

Note: This page contains sample records for the topic "highly fractured continuous" 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
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261

Hydraulic fracturing of jointed formations  

DOE Green Energy (OSTI)

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

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

1986-01-01T23:59:59.000Z

262

Irradiation Effects on Human Cortical Bone Fracture Behavior  

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

Irradiation Effects on Human Cortical Bone Fracture Behavior Print Irradiation Effects on Human Cortical Bone Fracture Behavior Print Human bone is strong but still fallible. To better predict fracturing in bone, researchers need a mechanistic framework to understand the changes taking place on different size scales within bone, as well as the role of sustained irradiation damage. Combining in situ mechanical testing with synchrotron x-ray diffraction imaging and/or tomography, is a popular method of investigating micrometer deformation and fracture behavior in bone. However, the role that irradiation plays in these high-exposure experiments, and how it affects the properties of bone tissue, are not yet fully understood. A team of researchers led by Robert O. Ritchie at the Lawrence Berkeley National Laboratory and the University of California, Berkeley used synchrotron radiation micro-tomography at Advanced Light Source Beamline 8.3.2 to investigate changes in crack path and toughening mechanisms in human cortical bone with increased exposure to radiation, finding that exposure to high levels of irradiation can lead to drastic losses in strength, ductility, and toughness.

263

DEFORMATION AND FRACTURE OF POLYCRYSTALLINE LITHIUM FLUORIDE (thesis)  

SciTech Connect

Techniques for forming polycrystalline LiF from the melt and for fabricating test specimens were developed and evaluated using single-crystal LiF as a control. Large -grain polycrystalline specimens tested in fourpoint loading always showed some plastic deformation (0.078 to 0.798%) before fracture, but the plastic flow was sharpiy reduced from that of single crystals. An etch was developed revealing dislocations on all crystallographic faces of LiF. Details of plastic deformation in polycrystalline material were investigated. Deformation was inhomogeneous among the grains of an aggregate because of differences in orientation with respect to the applied stress, also within individual grains because of interactions between adjoining grains. Grain boundaries were barriers to slip, but stresses resulting from slip in one grain were transmitted to neighboring grains and often caused local deformation near the boundary. Because of local stresses, local slip systems operated although the resolved shear stresses on them from the applied load were below the critical yield stress. In one case, slip occurred on an (010) plane. Three-grain junctions were areas of high residual stress. Fractures originated at boundaries at or near 3-grain junctions, not as a result of inherent boundary weakness but rather because of high stresses developed at the boundary. A quantitative expression for fracture originating in a slip band was applied to one type of fracture. (auth)

Scott, W.D.

1962-09-14T23:59:59.000Z

264

Irradiation Effects on Human Cortical Bone Fracture Behavior  

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

Irradiation Effects on Human Cortical Bone Fracture Behavior Print Irradiation Effects on Human Cortical Bone Fracture Behavior Print Human bone is strong but still fallible. To better predict fracturing in bone, researchers need a mechanistic framework to understand the changes taking place on different size scales within bone, as well as the role of sustained irradiation damage. Combining in situ mechanical testing with synchrotron x-ray diffraction imaging and/or tomography, is a popular method of investigating micrometer deformation and fracture behavior in bone. However, the role that irradiation plays in these high-exposure experiments, and how it affects the properties of bone tissue, are not yet fully understood. A team of researchers led by Robert O. Ritchie at the Lawrence Berkeley National Laboratory and the University of California, Berkeley used synchrotron radiation micro-tomography at Advanced Light Source Beamline 8.3.2 to investigate changes in crack path and toughening mechanisms in human cortical bone with increased exposure to radiation, finding that exposure to high levels of irradiation can lead to drastic losses in strength, ductility, and toughness.

265

Irradiation Effects on Human Cortical Bone Fracture Behavior  

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

Irradiation Effects on Human Cortical Bone Fracture Behavior Print Irradiation Effects on Human Cortical Bone Fracture Behavior Print Human bone is strong but still fallible. To better predict fracturing in bone, researchers need a mechanistic framework to understand the changes taking place on different size scales within bone, as well as the role of sustained irradiation damage. Combining in situ mechanical testing with synchrotron x-ray diffraction imaging and/or tomography, is a popular method of investigating micrometer deformation and fracture behavior in bone. However, the role that irradiation plays in these high-exposure experiments, and how it affects the properties of bone tissue, are not yet fully understood. A team of researchers led by Robert O. Ritchie at the Lawrence Berkeley National Laboratory and the University of California, Berkeley used synchrotron radiation micro-tomography at Advanced Light Source Beamline 8.3.2 to investigate changes in crack path and toughening mechanisms in human cortical bone with increased exposure to radiation, finding that exposure to high levels of irradiation can lead to drastic losses in strength, ductility, and toughness.

266

Irradiation Effects on Human Cortical Bone Fracture Behavior  

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

Irradiation Effects on Human Irradiation Effects on Human Cortical Bone Fracture Behavior Irradiation Effects on Human Cortical Bone Fracture Behavior Print Wednesday, 28 July 2010 00:00 Human bone is strong but still fallible. To better predict fracturing in bone, researchers need a mechanistic framework to understand the changes taking place on different size scales within bone, as well as the role of sustained irradiation damage. Combining in situ mechanical testing with synchrotron x-ray diffraction imaging and/or tomography, is a popular method of investigating micrometer deformation and fracture behavior in bone. However, the role that irradiation plays in these high-exposure experiments, and how it affects the properties of bone tissue, are not yet fully understood. A team of researchers led by Robert O. Ritchie at the Lawrence Berkeley National Laboratory and the University of California, Berkeley used synchrotron radiation micro-tomography at Advanced Light Source Beamline 8.3.2 to investigate changes in crack path and toughening mechanisms in human cortical bone with increased exposure to radiation, finding that exposure to high levels of irradiation can lead to drastic losses in strength, ductility, and toughness.

267

Irradiation Effects on Human Cortical Bone Fracture Behavior  

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

Irradiation Effects on Human Cortical Bone Fracture Behavior Print Irradiation Effects on Human Cortical Bone Fracture Behavior Print Human bone is strong but still fallible. To better predict fracturing in bone, researchers need a mechanistic framework to understand the changes taking place on different size scales within bone, as well as the role of sustained irradiation damage. Combining in situ mechanical testing with synchrotron x-ray diffraction imaging and/or tomography, is a popular method of investigating micrometer deformation and fracture behavior in bone. However, the role that irradiation plays in these high-exposure experiments, and how it affects the properties of bone tissue, are not yet fully understood. A team of researchers led by Robert O. Ritchie at the Lawrence Berkeley National Laboratory and the University of California, Berkeley used synchrotron radiation micro-tomography at Advanced Light Source Beamline 8.3.2 to investigate changes in crack path and toughening mechanisms in human cortical bone with increased exposure to radiation, finding that exposure to high levels of irradiation can lead to drastic losses in strength, ductility, and toughness.

268

Feasibility of an acoustic technique for fracture detection  

DOE Green Energy (OSTI)

A field experiment was conducted at a granite quarry to determine the feasibility of an acoustic, downhole technique for location of fractures in the vicinity of boreholes. The frequency used in this test was about 5 kHz; a frequency well above the seismic frequency commonly used in reservoir evaluations. An existing flame-cut slot in the granite at the test site was filled with water to simulate a fracture. A high-energy piezoelectric transmitter was located in a borehole 8 meters from the water-filled slot, and a commercial piezoelectric transducer was used as a receiver in a borehole 4 meters from the slot. Both transducers could be rotated for maximum transmission or reception for either the compressional wave or the shear wave. During the experiment, reflections from the simulated fracture were obtained with the transducers oriented only for shear wave illumination and detection. These test results suggest that a high-frequency shear wave can be used to detect fractures located away from a borehole. 2 refs., 2 figs.

Chang, H.T.

1985-01-01T23:59:59.000Z

269

Fluid Flow Within Fractured Porous Media  

Science Conference Proceedings (OSTI)

Fractures provide preferential flow paths to subterranean fluid flows. In reservoir scale modeling of geologic flows fractures must be approximated by fairly simple formulations. Often this is accomplished by assuming fractures are parallel plates subjected to an applied pressure gradient. This is known as the cubic law. An induced fracture in Berea sandstone has been digitized to perform numerical flow simulations. A commercially available computational fluid dynamics software package has been used to solve the flow through this model. Single phase flows have been compared to experimental works in the literature to evaluate the accuracy with which this model can be applied. Common methods of fracture geometry classification are also calculated and compared to experimentally obtained values. Flow through regions of the fracture where the upper and lower fracture walls meet (zero aperture) are shown to induce a strong channeling effect on the flow. This model is expanded to include a domain of surrounding porous media through which the flow can travel. The inclusion of a realistic permeability in this media shows that the regions of small and zero apertures contribute to the greatest pressure losses over the fracture length and flow through the porous media is most prevalent in these regions. The flow through the fracture is shown to be the largest contributor to the net flow through the media. From this work, a novel flow relationship is proposed for flow through fractured media.

Crandall, D.M.; Ahmadi, G. (Clarkson Univ., Potsdam, NY); Smith, D.H.; Bromhal, G.S.

2006-10-01T23:59:59.000Z

270

Well test analysis in fractured media  

DOE Green Energy (OSTI)

The behavior of fracture systems under well test conditions and methods for analyzing well test data from fractured media are investigated. Several analytical models are developed to be used for analyzing well test data from fractured media. Numerical tools that may be used to simulate fluid flow in fractured media are also presented. Three types of composite models for constant flux tests are investigated. These models are based on the assumption that a fracture system under well test conditions may be represented by two concentric regions, one representing a small number of fractures that dominates flow near the well, and the other representing average conditions farther away from the well. Type curves are presented that can be used to find the flow parameters of these two regions and the extent of the inner concentric region. Several slug test models with different geometric conditions that may be present in fractured media are also investigated. A finite element model that can simulate transient fluid flow in fracture networks is used to study the behavior of various two-dimensional fracture systems under well test conditions. A mesh generator that can be used to model mass and heat flow in a fractured-porous media is presented.

Karasaki, K.

1987-04-01T23:59:59.000Z

271

Nonlinear Hertzian indentation fracture mechanics  

SciTech Connect

Indentation cracking under blunt indenters is analyzed using nonlinear fracture mechanics. The usual assumptions of linear elastic fracture mechanics have been replaced with a nonlinear load vs load-point displacement curve while assuming the material is linear elastic. The load, the load-point displacement, and a function of the crack area have been related to the crack driving force, J, while assuming a cone fracture under the Hertzian sphere. Experimentally, it was found that the load-displacement curve during loading, cracking, and unloading is nonlinear. The crack length is empirically shown to be proportional to the load-point displacement for several indenters. The experimentally measured relations between indenter load, load-point displacement, and crack geometries are then analyzed with mechanical energy balances based on the similitude of crack lengths with load-point displacements. The Hertz hardness that describes the nonlinear load vs load-point displacement relation during cracking is derived on the constant J line in load-displacement space. Finally, well-known experimental expressions that relate load to crack length are shown to be indistinguishable from the load-point displacement analysis reported.

Burns, S.J.; Chia, K.Y. [Univ. of Rochester, NY (United States). Dept. of Mechanical Engineering

1995-09-01T23:59:59.000Z

272

Effects of alkali-metal impurities on fracture toughness of 2090 Al-Li-Cu extrusions  

Science Conference Proceedings (OSTI)

The effects of alkali-metal impurity (AMI) content, temperature, and crack-mouth-opening displacement (CMOD) rate on the fracture toughness of 2090-T8 Al-Li-Cu alloy extrusions were studied, particularly for short-transverse (S-L) orientations. Decreasing AMI content resulted in increasing room-temperature fracture toughness, especially for underaged S-L and T-L specimens. Unlike most Al-Li based alloys, material with very low (AMIs produced by vacuum refining had a high S-L fracture toughness (up to 38 MPa{radical}m for proof strengths {approximately}440 MPa) as well as high toughness in other orientations. The increase in room-temperature fracture toughness with decreasing AMI content was associated with a decrease in the proportion o brittle intergranular and cleavage-like islands, and a corresponding increase in the proportion of high energy dimpled fracture modes, on fracture surfaces. Both the present and previous studies indicate that the brittle islands result from liquid-metal embrittlement due to the presence of discrete sodium-potassium rich liquid phases. For medium to high AMI contents (5 to 37 wt ppm), S-L fracture toughness increased with decreasing temperature due to solidification of these phases and a consequent decrease in the mobility of embrittling atoms. The ability of embrittling atoms to keep up with crack tips also depended on crack velocity so that CMOD rate influenced fracture toughness. The grain structure (degree of recrystallization) appeared to be another important parameter affecting fracture toughness.

Sweet, E.D.; Bennett, C.G.; Musulin, I. [Comalco Research Centre, Thomastown, Victoria (Australia); Lynch, S.P.; Nethercott, R.B. [Defence Science and Technology Organisation, Melbourne, Victoria (Australia)

1996-11-01T23:59:59.000Z

273

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

E-Print Network (OSTI)

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

Faybishenko, Boris; Witherspoon, Paul A.

2004-01-01T23:59:59.000Z

274

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

275

Vaporizing Flow in Hot Fractures: Observations from Laboratory Experiments  

DOE Green Energy (OSTI)

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

Kneafsey, T.; Pruess, K.

1998-12-01T23:59:59.000Z

276

Using seismic tomography to characterize fracture systems induced by hydraulic fracturing  

DOE Green Energy (OSTI)

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

Fehler, M.; Rutledge, J.

1995-01-01T23:59:59.000Z

277

Continuous flow separation techniques for microchemical synthesis  

E-Print Network (OSTI)

Performing multistep microchemical synthesis requires many techniques from combining micromixers in series to the development of continuous microfluidic separation tools. Safety, high heat and mass transfer rates, and cost ...

Kralj, Jason G

2006-01-01T23:59:59.000Z

278

Comparison of fracture behavior for low-swelling ferritic and austenitic alloys irradiated in the Fast Flux Test Facility (FFTF) to 180 DPA  

Science Conference Proceedings (OSTI)

Fracture toughness testing was conducted to investigate the radiation embrittlement of high-nickel superalloys, modified austenitic steels and ferritic steels. These materials have been experimentally proven to possess excellent resistance to void swelling after high neutron exposures. In addition to swelling resistance, post-irradiation fracture resistance is another important criterion for reactor material selection. By means of fracture mechanics techniques the fracture behavior of those highly irradiated alloys was characterized in terms of irradiation and test conditions. Precipitation-strengthened alloys failed by channel fracture with very low postirradiation ductility. The fracture toughness of titanium-modified austenitic stainless steel D9 deteriorates with increasing fluence to about 100 displacement per atom (dpa), the fluence level at which brittle fracture appears to occur. Ferritic steels such as HT9 are the most promising candidate materials for fast and fusion reactor applications. The upper-shelf fracture toughness of alloy HT9 remained adequate after irradiation to 180 dpa although its ductile- brittle transition temperature (DBTT) shift by low temperature irradiation rendered the material susceptible to brittle fracture at room temperature. Understanding the fracture characteristics under various irradiation and test conditions helps reduce the potential for brittle fracture by permitting appropriate measure to be taken.

Huang, F.H.

1992-02-01T23:59:59.000Z

279

A casting and imaging technique for determining void geometry and relative permeability behavior of a single fracture specimen  

DOE Green Energy (OSTI)

A casting technique has been developed for making translucent replicas of the void space of natural rock fractures. Attenuation of light shined through the cast combined with digital image analysis provides a pointwise definition of fracture apertures. The technique has been applied to a fracture specimen from Dixie Valley, Nevada, and the measured void space geometry has been used to develop theoretical predictions of two-phase relative permeability. A strong anisotropy in relative permeabilities has been found, which is caused by highly anisotropic spatial correlations among fracture apertures. 16 refs., 6 figs.

Cox, B.L.; Pruess, K.; Persoff, P.

1990-01-01T23:59:59.000Z

280

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

Note: This page contains sample records for the topic "highly fractured continuous" 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

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

282

Injection into a fractured geothermal reservoir  

DOE Green Energy (OSTI)

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

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

1980-05-01T23:59:59.000Z

283

A finite element model for three dimensional hydraulic fracturing  

Science Conference Proceedings (OSTI)

This paper is devoted to the development of a model for the numerical simulation of hydraulic fracturing processes with 3d fracture propagation. It takes into account the effects of fluid flow inside the fracture, fluid leak-off through fracture walls ... Keywords: boundary elements, finite elements, hydraulic fracturing, petroleum recovery

Philippe R. B. Devloo; Paulo Dore Fernandes; Sônia M. Gomes; Cedric Marcelo Augusto Ayala Bravo; Renato Gomes Damas

2006-11-01T23:59:59.000Z

284

Self-decomposable Fibrous Bridging Additives for Temporary Cementitious Fracture Sealers in EGS Wells  

SciTech Connect

This study evaluates compatibility of a self-degradable temporary fracture sealer with the drilling mud and plugging and self-degrading performance of different fibers to be used in combination with the sealer. The sodium silicate-activated slag/Class C fly ash (SSASC) cementitious sealer must plug fractures at 85oC to allow continuous well drilling and it must degrade and leave the fractures open for water at later times when exposed to temperatures above 200oC. The sealer showed good compatibility with the mud. Even the blend of 80/20 vol.% of sealer/mud reached a compressive strength of more than 2000 psi set as one of the material criteria, mostly due to the additional activation of the slag and Class C fly ash by the alkaline ingredient present in the drilling fluid. In contrast, the drilling fluid was detrimental to the compressive strength development in conventional Class G well cement, so that it failed to meet this criterion. Among several organic fibers tested both polyvinyl alcohol (PVA)-and nylon-based fibers showed adequate plugging of the sealer in slot nozzles of 1-in. wide x 6-in. long x 0.08 in. and 0.24 in. high under pressures up to 700 psi. PVA fibers displayed better compressive toughness and self-degrading properties than nylon. The compressive toughness of sealers made by adding 1.0 wt% 6 mm-length PVA and 0.5 wt% 19 mm-length PVA was 9.5-fold higher than that of a non-bridged sealer. One factor governing the development of such high toughness was an excellent adherence of PVA to the SSASC cement. The alkali-catalyzed self-decomposition of PVA at 200°C led to the morphological transformation of the material from a fibrous structure to a microscale flake-like structure that helped the desirable conversion of the sealer into small fragments. In contrast, nylon’s decomposition provided a reticular network structure in the self-degraded sealer resulting in bigger fragments compared against the sealer with PVA. The PVA fiber has a high potential as a self-decomposable bridging additive in the SSASC cement sealer.

Sugama T.; Pyatina, T.; Gill, S.; Kisslinger, K.; Iverson, B.; Bour, D.

2012-11-01T23:59:59.000Z

285

Naturally fractured tight gas reservoir detection optimization  

SciTech Connect

The goal of the work this quarter has been to partition and high-grade the Greater Green River basin for exploration efforts in the Upper Cretaceous tight gas play and to initiate resource assessment of the basin. The work plan for the quarter of July 1-September 30, 1998 comprised three tasks: (1) Refining the exploration process for deep, naturally fractured gas reservoirs; (2) Partitioning of the basin based on structure and areas of overpressure; (3) Examination of the Kinney and Canyon Creek fields with respect to the Cretaceous tight gas play and initiation of the resource assessment of the Vermilion sub-basin partition (which contains these two fields); and (4) Initiation analysis of the Deep Green River Partition with respect to the Stratos well and assessment of the resource in the partition.

NONE

1998-11-30T23:59:59.000Z

286

The Countdown Continues INSIDE  

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

1, 1996 1, 1996 Number 11 The Countdown Continues INSIDE 2 University Close-Up: Elmhurst College 4 DOE Reviews DZero Upgrade 5 Griffing Appointed ES&H Head 10 Laboratory Adopts More Efficient Payroll System Only a month remains before fixed-target experiments will resume at Fermilab. As the days dwindle down to a precious few, experi- menters and staff throughout the Laboratory scramble to get ready. The last issue of FermiNews reported on countdown activities for the Accelerator and Computing Divisions and the Facilities Engineering Services Section. For this issue the Research Division, the Physics Section and five of the 10 experiments f continued on page 6 Photo by Reidar Hahn described their down-to-the-wire preparations. "It's nip and tuck in terms of building the

287

high  

Gasoline and Diesel Fuel Update (EIA)

0 0 Highlights International Oil Markets Prices. We have raised our world oil price projection by about $2 per barrel for this month because of assumed greater compliance by OPEC to targeted cuts, especially for the second quarter of 2000 (Figure 1). The expected decline in world petroleum inventories continues (Figure 2), and, given the generally stiff resolve of OPEC members to maintain production cuts, any sign of a turnaround in stocks may be postponed until later this year than previously assumed (Q3 instead of Q2). Our current estimate for the average import cost this past January is now $25 per barrel, a nearly $15-per-barrel increase from January 1999. Crude oil prices are expected to remain at relatively high levels for the first half of 2000, but

288

Continuous Emissions Monitoring Guidelines  

Science Conference Proceedings (OSTI)

Since the 2002 update of this manual, the Environmental Protection Agency (EPA) has been extremely active in its efforts to expand continuous emissions monitoring (CEM) requirements through a variety of regulatory instruments. Additional monitoring requirements have resulted from EPA's Clean Air Interstate Rule and Cross-State Air Pollution Rule. EPA attempted to impose mercury (Hg) monitoring requirements in its now-vacated Clean Air Mercury Rule. Most recently, EPA has proposed mercury, particulate mat...

2011-12-20T23:59:59.000Z

289

Continuous steel production and apparatus  

DOE Patents (OSTI)

A process for continuous refining of steel via multiple distinct reaction vessels for melting, oxidation, reduction, and refining for delivery of steel continuously to, for example, a tundish of a continuous caster system, and associated apparatus.

Peaslee, Kent D. (Rolla, MO); Peter, Jorg J. (McMinnville, OR); Robertson, David G. C. (Rolla, MO); Thomas, Brian G. (Champaign, IL); Zhang, Lifeng (Trondheim, NO)

2009-11-17T23:59:59.000Z

290

The Performance of Fractured Horizontal Well in Tight Gas Reservoir  

E-Print Network (OSTI)

Horizontal wells have been used to increase reservoir recovery, especially in unconventional reservoirs, and hydraulic fracturing has been applied to further extend the contact with the reservoir to increase the efficiency of development. In the past, many models, analytical or numerical, were developed to describe the flow behavior in horizontal wells with fractures. Source solution is one of the analytical/semi-analytical approaches. To solve fractured well problems, source methods were advanced from point sources to volumetric source, and pressure change inside fractures was considered in the volumetric source method. This study aims at developing a method that can predict horizontal well performance and the model can also be applied to horizontal wells with multiple fractures in complex natural fracture networks. The method solves the problem by superposing a series of slab sources under transient or pseudosteady-state flow conditions. The principle of the method comprises the calculation of semi-analytical response of a rectilinear reservoir with closed outer boundaries. A statistically assigned fracture network is used in the study to represent natural fractures based on the spacing between fractures and fracture geometry. The multiple dominating hydraulic fractures are then added to the natural fracture system to build the physical model of the problem. Each of the hydraulic fractures is connected to the horizontal wellbore, and the natural fractures are connected to the hydraulic fractures through the network description. Each fracture, natural or hydraulically induced, is treated as a series of slab sources. The analytical solution of superposed slab sources provides the base of the approach, and the overall flow from each fracture and the effect between the fractures are modeled by applying superposition principle to all of the fractures. It is assumed that hydraulic fractures are the main fractures that connect with the wellbore and the natural fractures are branching fractures which only connect with the main fractures. The fluid inside of the branch fractures flows into the main fractures, and the fluid of the main fracture from both the reservoir and the branch fractures flows to the wellbore. Predicting well performance in a complex fracture network system is extremely challenged. The statistical nature of natural fracture networks changes the flow characteristic from that of a single linear fracture. Simply using the single fracture model for individual fracture, and then adding the flow from each fracture for the network could introduce significant error. This study provides a semi-analytical approach to estimate well performance in a complex fracture network system.

Lin, Jiajing

2011-12-01T23:59:59.000Z

291

Hydraulic fracturing and shale gas extraction.  

E-Print Network (OSTI)

??In the past decade the technique of horizontal drilling and hydraulic fracturing has been improved so much that it has become a cost effective method… (more)

Klein, Michael

2012-01-01T23:59:59.000Z

292

Geothermal: Sponsored by OSTI -- Injection through fractures  

Office of Scientific and Technical Information (OSTI)

Injection through fractures Geothermal Technologies Legacy Collection HelpFAQ | Site Map | Contact Us | Admin Log On HomeBasic Search About Publications Advanced Search New Hot...

293

Fatigue and Fracture I - Programmaster.org  

Science Conference Proceedings (OSTI)

Oct 10, 2012 ... Fretting Corrosion Induced Fracture of a Floating Bearing Base Plate in a 250 Tons Yankee Paper Drum: Pierre Dupont1; 1Schaeffler Belgium ...

294

Hydraulic fractures traced by monitoring microseismic events  

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

Summary: The trend toward production of hydrocarbons from unconventional reservoirs (tight gas, shale oilgas) has caused a large increase in the use of hydraulic fracture...

295

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

296

Fracture of Thin Films and Nanomaterials  

Science Conference Proceedings (OSTI)

Mar 4, 2013 ... Fracture Toughness of SPD-Deformed Nanostructured Rail Steels and Its Implications on the In-Service Behaviour: Christoph Kammerhofer1; ...

297

Deformation and Fracture - Programmaster.org  

Science Conference Proceedings (OSTI)

Mar 14, 2012 ... Investigations on the crack propagation resistance showed an increasing fracture resistance with crack extension, so-called R-curve behavior.

298

Microseismic Tracer Particles for Hydraulic Fracturing  

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

The trend toward production of hydrocarbons from unconventional reservoirs (tight gas, shale oilgas) has caused a large increase in the use of hydraulic fracture stimulation of...

299

Molecular Dynamics Simulation of Thermoset Fracture with ...  

Science Conference Proceedings (OSTI)

The effects of resin chain extensibility and dilution on fracture behavior are studied by testing a variety of molecular systems. The molecular bases for precursors ...

300

MML Leads Discussion of Dynamic Fracture Testing  

Science Conference Proceedings (OSTI)

Dynamic Fracture in Steel. ... More recently, the pipeline industry has been adopting the CTOA ... fatigue characteristics of new pipeline steels, as these ...

2012-10-15T23:59:59.000Z

Note: This page contains sample records for the topic "highly fractured continuous" 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

Well test analysis in fractured media  

DOE Green Energy (OSTI)

In this study the behavior of fracture systems under well test conditions and methods for analyzing well test data from fractured media are investigated. Several analytical models are developed to be used for analyzing well test data from fractured media. Numerical tools that may be used to simulate fluid flow in fractured media are also presented. Three types of composite models for constant flux tests are investigated. Several slug test models with different geometric conditions that may be present in fractured media are also investigated. A finite element model that can simulate transient fluid flow in fracture networks is used to study the behavior of various two-dimensional fracture systems under well test conditions. A mesh generator that can be used to model mass and heat flow in a fractured-porous media is presented. This model develops an explicit solution in the porous matrix as well as in the discrete fractures. Because the model does not require the assumptions of the conventional double porosity approach, it may be used to simulate cases where double porosity models fail.

Karasaki, K.

1986-04-01T23:59:59.000Z

302

Geothermal: Sponsored by OSTI -- Hydraulic fracturing: insights...  

Office of Scientific and Technical Information (OSTI)

Hydraulic fracturing: insights from field, lab, and numerical studies Geothermal Technologies Legacy Collection HelpFAQ | Site Map | Contact Us | Admin Log On HomeBasic Search...

303

The Dynamics of Rapid Fracture: Instabilities, Nonlinearities and Length Scales  

E-Print Network (OSTI)

The failure of materials and interfaces is mediated by cracks, nearly singular dissipative structures that propagate at velocities approaching the speed of sound. Crack initiation and subsequent propagation -- the dynamic process of fracture -- couples a wide range of time and length scales. Crack dynamics challenge our understanding of the fundamental physics processes that take place in the extreme conditions within the nearly singular region where material failure occurs. Here, we first briefly review the classic approach to dynamic fracture, "Linear Elastic Fracture Mechanics" (LEFM), and discuss its successes and limitations. We show how, on the one hand, recent experiments performed on straight cracks propagating in soft brittle materials have quantitatively confirmed the predictions of this theory to an unprecedented degree. On the other hand, these experiments show how LEFM breaks down as the singular region at the tip of a crack is approached. This breakdown naturally leads to a new theoretical framework coined "Weakly Nonlinear Fracture Mechanics", where weak elastic nonlinearities are incorporated. The stronger singularity predicted by this theory gives rise to a new and intrinsic length scale, $\\ell_{nl}$. These predictions are verified in detail through direct measurements. We then theoretically and experimentally review how the emergence of $\\ell_{nl}$ is linked to a new equation for crack motion, which predicts the existence of a high-speed oscillatory crack instability whose wave-length is determined by $\\ell_{nl}$. We conclude by delineating outstanding challenges in the field.

Eran Bouchbinder; Tamar Goldman; Jay Fineberg

2013-05-05T23:59:59.000Z

304

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

DOE Green Energy (OSTI)

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

Zyvoloski, G.

1985-01-01T23:59:59.000Z

305

A discrete fracture model for a hot dry rock geothermal reservoir  

DOE Green Energy (OSTI)

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

Robinson, B.A.

1989-01-01T23:59:59.000Z

306

Application of the pseudolinear flow model to the pressure transient analysis of fractured wells  

SciTech Connect

The theoretical basis for the pseudolinear flow model is established. It is demonstrated by using an analytical model that the linear flow graph (p vs ..sqrt..t) can be extended to the analysis of pressure data of fractured wells intersected by an intermediate or a high conductivity fracture ((k /SUB f/ b /SUB f/ greater than or equal to 15). It appears that the fracture conductivity effect during the pseudolinear flow period can be handled as a pseudo skin pressure drop which is additive to the pressure drop caused by fluid loss damage. The combination of the pseudolinear flow analysis with other interpretation techniques is illustrated through examples of field cases.

Cinco-Ley, H.; Rodriguez, F.; Samaniego, F.

1984-09-01T23:59:59.000Z

307

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

Science Conference Proceedings (OSTI)

Hydraulic fracturing has been used widely to stimulate production of oil, natural gas, and geothermal energy in formations with low natural permeability. Numerical optimization of fracture stimulation often requires a large number of evaluations of objective ... Keywords: Fractal dimension, Global sensitivity, Hydraulic fracturing, Optimization, Surrogate model

Mingjie Chen, Yunwei Sun, Pengcheng Fu, Charles R. Carrigan, Zhiming Lu, Charles H. Tong, Thomas A. Buscheck

2013-08-01T23:59:59.000Z

308

Characterization of EGS Fracture Network Lifecycles  

DOE Green Energy (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

309

GMINC - A MESH GENERATOR FOR FLOW SIMULATIONS IN FRACTURED RESERVOIRS  

E-Print Network (OSTI)

Simulation of Fluid Flow in Fractured Porous Media, Watergovern fluid flow in fractured porous media. These are (i)for Modeling Fluid and Heat Flow in fractured Porous Media,

Pruess, K.

2010-01-01T23:59:59.000Z

310

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

311

Improvement of tubulars used for fracturing in hot dry rock wells  

DOE Green Energy (OSTI)

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

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

1984-04-01T23:59:59.000Z

312

Continuous chain bit development  

DOE Green Energy (OSTI)

The continuous chain drill is a diamond drill bit in which the cutting surface can be replaced while the bit is still in the hole. The first prototype of the chain drill system was fabricated and tested in 1977. Problems were encountered with the mechanism used to cycle the bit. A second prototype bit was designed to circumvent these problems. An accelerated development and test program has provided field test results on Prototype II in less than 2 years. Field testing at Nevada Test Site has proven the feasibility of the downhole changing mechanism. The development and testing of this prototype are described.

St. Clair, J.A.; Duimstra, F.A.; Varnado, S.G.

1979-01-01T23:59:59.000Z

313

CONTINUOUS GAS ANALYZER  

DOE Patents (OSTI)

A reagent gas and a sample gas are chemically combined on a continuous basis in a reaction zone maintained at a selected temperature. The reagent gas and the sample gas are introduced to the reaction zone at preselected. constant molar rates of flow. The reagent gas and the selected gas in the sample mixture combine in the reaction zone to form a product gas having a different number of moles from the sum of the moles of the reactants. The difference in the total molar rates of flow into and out of the reaction zone is measured and indicated to determine the concentration of the selected gas.

Katz, S.; Weber, C.W.

1960-02-16T23:59:59.000Z

314

Experimental study of fracture development in multilayers of contrasting strength and ductility  

E-Print Network (OSTI)

The effect of mean ductility, interlayer thickness, and magnitude of shortening on fracture development in bedded rock was investigated by shortening multilayer cylinders (5 cm dia.) 4 to 14% normal to layering in a triaxial apparatus. Multilayers were constructed by stacking two 1.4-cm thick layers of Berea Sandstone (relatively strong and brittle) with interlayers of Indiana Limestone (relatively weak and ductile). Thickness of the interlayer between the sandstone was 30%, 100%, or 150% of the thickness of the sandstone layer. Mean ductility was varied by shortening at confining pressures (Pc) of 5, 25, 50, and 100 MPa. Sandstone layers fracture at all conditions. Fractures have preferred orientation symmetric to the cylinder axis, and display systematic spacing. At the lowest Pc and mean ductility, fractures in the sandstone are dominantly opening mode (joints) and mixed mode fractures oriented at high angles to layer boundaries. At greater Pc and mean ductility, fractures are dominantly shear mode (faults) and display conjugate geometry. Average dihedral angle of the conjugates increases from 16 to 67 degrees with increase in mean ductility. Maximum fracture density in the sandstone occurs at intermediate mean ductility and maximum interlayer thickness. Fractures propagate from the sandstone into the limestone and may link across the limestone interlayer as shortening is increased. Linkage is enhanced with decreasing mean ductility and interlayer thickness, and increasing shortening. At high mean ductility, fractures are confined to the sandstone layers. Limestone deforms by faulting and compactive cataclastic flow at low and high mean ductility, respectively. Faults in limestone are more variable in orientation and display larger dihedral angles than in the sandstone. Fracture mode and orientation are consistent with Mohr-Coulomb failure, and a spatially heterogeneous stress state where the most tensile stress occurs in the sandstone. Types of fracture networks in multilayer sequences with moderate ductility contrast vary from joints and faults, refracted faults, to faults and flow with increasing mean ductility. Fracture spacing depends on layer and interlayer thickness, mean ductility and ductility contrast, and magnitude of shortening.

Cubuk, Pelin

2002-01-01T23:59:59.000Z

315

VSP [Vertical Seismic Profiling] and cross hole tomographic imaging for fracture characterization  

SciTech Connect

For the past several years LBL has been carrying out experiments at various fractured rock sites to determine the fundamental nature of the propagation of seismic waves in fractured media. These experiments have been utilizing high frequency (1000 to 10000 Hz.) signals in a cross-hole configuration at scales of several tens of meters. Three component sources and receivers are used to map fracture density, and orientation. The goal of the experiments has been to relate the seismological parameters to the hydrological parameters, if possible, in order to provide a more accurate description of a starting model for hydrological characterization. The work is ultimately aimed at the characterization and monitoring of the Yucca Mountain site for the storage of nuclear waste. In addition to these controlled experiments multicomponent VSP work has been carried out at several sites to determine fracture characteristics. The results to date indicate that both P-wave and S-wave can be used to map the location of fractures. In addition, fractures that are open and conductive are much more visible to seismic waves that non-conductive fractures. The results of these tests indicate direct use in an unsaturated environment. 12 refs., 10 figs.

Majer, E.L.; Peterson, J.E.; Myer, L.R.; Karasaki, K.; Daley, T.M.; Long, J.C.S.

1989-09-01T23:59:59.000Z

316

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

Science Conference Proceedings (OSTI)

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

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

2012-05-01T23:59:59.000Z

317

Dynamic Fracture Conductivity—An Experimental Investigation Based on Factorial Analysis  

E-Print Network (OSTI)

This work is about fracture conductivity; how to measure and model it based on experimental data. It is also about how to determine the relative importance of the factors that affect its magnitude and how to predict its magnitude based on these factors. We dynamically placed the slurry hereby simulating the slurry placement procedure in a field-scale fracture. We also used factorial and fractional factorial designs as the basis of our experimental investigation. The analysis and interpretation of experimental results take into account the stochastic nature of the process. We found that the relative importance of the investigated factors is dependent on the presence of outliers and how they are handled. Based on our investigation we concluded that the investigated factors arranged in order of decreasing impact on conductivity are: closure stress, polymer loading, flow back rate, presence of breaker, temperature and proppant concentration. In particular, we find that at high temperatures, fracture conductivity was severely reduced due to the formation of a dense proppant-polymer cake. Also, dehydration of the residual gel in the fracture at high flow back rates appears to cause severe damage to conductivity at higher temperatures. This represents a new way of thinking about the fracture cleanup process; not only as a displacement process, but also as a displacement and evaporative process. In engineering practice, this implies that aggressive flow back schemes are not necessarily beneficial for conductivity development. Also, we find that at low proppant concentrations, there is the increased likelihood of the formation of channels and high porosity fractures resulting in high fracture conductivities. The uniqueness of this work is a focus on the development of a conductivity model using regression analysis and also the illustration of a procedure that can be used to develop a conductivity model using dimensional analysis. We reviewed both methodologies and applied them to the challenge of modeling fracture conductivity from experimental studies.

Awoleke, Obadare O

2013-05-01T23:59:59.000Z

318

Hydraulic fracture stimulation treatment of Well Baca 23. Geothermal Reservoir Well-Stimulation Program  

DOE Green Energy (OSTI)

Well Stimulation Experiment No. 5 of the Geothermal Reservoir Well Stimulation Program (GRWSP) was performed on March 22, 1981 in Baca 23, located in Union's Redondo Creek Project Area in Sandoval County, New Mexico. The treatment selected was a large hydraulic fracture job designed specifically for, and utilizing frac materials chosen for, the high temperature geothermal environment. The well selection, fracture treatment, experiment evaluation, and summary of the job costs are presented herein.

Not Available

1981-06-01T23:59:59.000Z

319

Finding Large Aperture Fractures in Geothermal Resource Areas...  

Open Energy Info (EERE)

low-permeability fractures and LAF's (Large Aperature Fractures). USG will develop and test the combination of three-component,long-offset seismic surveying, permanent scatter...

320

Characterizing Fractures in Geysers Geothermal Field by Micro...  

Open Energy Info (EERE)

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

Note: This page contains sample records for the topic "highly fractured continuous" 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

Modeling Of Hydraulic Fracture Network Propagation In Shale Gas Reservoirs.  

E-Print Network (OSTI)

??The most effective method for stimulating shale gas reservoirs is massive hydraulic fracture treatments. Recent fracture diagnostic technologies such as microseismic technology have shown that… (more)

Ahn, Chong

2012-01-01T23:59:59.000Z

322

Microseismicity, stress, and fracture in the Coso geothermal...  

Open Energy Info (EERE)

Microearthquakes in the geothermal field are proposed as indicators of shear fracturing associated with fluid injection and circulation along major pre-existing fractures....

323

A physical model for fracture surface features in metallic glasses  

Science Conference Proceedings (OSTI)

Apr 30, 2010 ... at a rate of 1000 mm/ min, fracturing the grease in the sample. Photographs were then taken of the fracture surfaces. The photographs were ...

324

Irradiation Effects on Human Cortical Bone Fracture Behavior  

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

Irradiation Effects on Human Cortical Bone Fracture Behavior Print Human bone is strong but still fallible. To better predict fracturing in bone, researchers need a mechanistic...

325

An Alternate Approach for Characterizing the Fracture Resistance of ...  

Science Conference Proceedings (OSTI)

While the elastic properties and strength of fish scales have received considerable attention, the resistance to fracture has not. Here the fracture resistance of ...

326

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

E-Print Network (OSTI)

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

Rutqvist, J.

2011-01-01T23:59:59.000Z

327

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

Science Conference Proceedings (OSTI)

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

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

2011-10-01T23:59:59.000Z

328

Hydraulic Fracturing Technology | Department of Energy  

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

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

329

Occult fractures of the knee: tomographic evaluation  

SciTech Connect

Seven adults with painful effusions of the knee were examined for occult fractures using pluridirectional tomograph in the coronal and lateral planes. Six patients (ages 50 to 82 years) were osteopenic and gave histories ranging from none to mild trauma; one 26-year-old man was not osteopenic and had severe trauma. In all cases, routine radiographs were interpreted as negative, but tomography demonstrated a fracture. Five fractures were subchondral. Bone scans in 2 patients were positive. The authors conclude that osteopenic patients with a painful effusion of the knee should be considered to have an occult fracture. While bone scans may be helpful, tomography is recommended as the procedure of choice to define the location and extent of the fracture.

Apple, J.S.; Martinez, S.; Allen, N.B.; Caldwell, D.S.; Rice, J.R.

1983-08-01T23:59:59.000Z

330

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 is to increase the conductivity of the reservoir by the creation of fractures deep into the formation, changing the flow pattern from radial to linear flow. The dynamic conductivity test was used for this research to evaluate the effect of closure stress, temperature, proppant concentration, and flow back rates on fracture conductivity. The objective of performing a dynamic conductivity test is to be able to mimic actual field conditions by pumping fracturing fluid/proppant slurry fluid into a conductivity cell, and applying closure stress afterwards. In addition, a factorial design was implemented in order to determine the main effect of each of the investigated factors and to minimize the number of experimental runs. Due to the stochastic nature of the dynamic conductivity test, each experiment was repeated several times to evaluate the consistency of the results. Experimental results indicate that the increase in closure stress has a detrimental effect on fracture conductivity. This effect can be attributed to the reduction in fracture width as closure stress was increased. Moreover, the formation of channels at low proppant concentration plays a significant role in determining the final conductivity of a fracture. The presence of these channels created an additional flow path for nitrogen, resulting in a significant increase in the conductivity of the fracture. In addition, experiments performed at high temperatures and stresses exhibited a reduction in fracture conductivity. The formation of a polymer cake due to unbroken gel dried up at high temperatures further impeded the propped conductivity. The effect of nitrogen rate was observed to be inversely proportional to fracture conductivity. The significant reduction in fracture conductivity could possibly be due to the effect of polymer dehydration at higher flow rates and temperatures. However, there is no certainty from experimental results that this conductivity reduction is an effect that occurs in real fractures or whether it is an effect that is only significant in laboratory conditions.

Romero Lugo, Jose 1985-

2012-12-01T23:59:59.000Z

331

CONTINUOUSLY SENSITIVE BUBBLE CHAMBER  

DOE Patents (OSTI)

A radiation detector of the bubble chamber class is described which is continuously sensitive and which does not require the complex pressure cycling equipment characteristic of prior forms of the chamber. The radiation sensitive element is a gas-saturated liquid and means are provided for establishing a thermal gradient across a region of the liquid. The gradient has a temperature range including both the saturation temperature of the liquid and more elevated temperatures. Thus a supersaturated zone is created in which ionizing radiations may give rise to visible gas bubbles indicative of the passage of the radiation through the liquid. Additional means are provided for replenishing the supply of gas-saturated liquid to maintaincontinuous sensitivity.

Good, R.H.

1959-08-18T23:59:59.000Z

332

Ohno continuous casting  

SciTech Connect

Production of net-shape products directly from the liquid is an attractive manufacturing route for alloys that are difficult to process or that cannot be rolled, drawn, or extruded. Developed at the Chiba Institute of Technology in Japan, the Ohno Continuous Casting (OCC) approach not only provides significant cost savings, but also has the potential to create new products. OCC process equipment includes a melting furnace, crucible, mold level-control block, cooling device, and pinch rolls. OCC is currently used to produce copper rods and wires for audio and video cables, and aluminum alloy welding rods for hard-surfacing applications. For example, Mitsui Engineering and Ship Building Co. has used OCC to produce copper tubing products with internal fins and partitions for applications such as heat exchanger tubes and induction coils.

Soda, H.; McLean, A. [Univ. of Toronto, Ontario (Canada); Motoyasu, G.; Ohno, A. [Chiba Institute of Technology (Japan)

1995-04-01T23:59:59.000Z

333

Nonlinear continuous feedback controllers  

E-Print Network (OSTI)

Packet-switched communication networks such as today's Internet are built with several interconnected core and distribution packet forwarding routers and several sender and sink transport agents. In order to maintain stability and avoid congestion collapse in the network, the sources control their rate behavior and voluntarily adjust their sending rates to accommodate other sources in the network. In this thesis, we study one class of sender rate control that is modeled using continuous first-order differential equation of the sending rates. In order to adjust the rates appropriately, the network sends continuous packet-loss feedback to the sources. We study a form of closed-loop feedback congestion controllers whose rate adjustments exhibit a nonlinear form. There are three dimensions to our work in this thesis. First, we study the network optimization problem in which sources choose utilities to maximize their underlying throughput. Each sender maximizes its utility proportional to the throughput achieved. In our model, sources choose a utility function to define their level of satisfaction of the underlying resource usages. The objective of this direction is to establish the properties of source utility functions using inequality constrained bounded sets and study the functional forms of utilities against a chosen rate differential equation. Second, stability of the network and tolerance to perturbation are two essential factors that keep communication networks operational around the equilibrium point. Our objective in this part of the thesis is to analytically understand the existence of local asymptotic stability of delayed-feedback systems under homogeneous network delays. Third, we propose a novel tangential controller for a generic maximization function and study its properties using nonlinear optimization techniques. We develop the necessary theoretical background and the properties of our controller to prove that it is a better rate adaptation algorithm for logarithmic utilities compared to the well-studied proportional controllers. We establish the asymptotic local stability of our controller with upper bounds on the increase / decrease gain parameters.

Sitharaman, Sai Ganesh

2005-05-01T23:59:59.000Z

334

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 results in early water breakthroughs, reduced tertiary recovery efficiency due to channeling of injected gas or fluids, dynamic calculations of recoverable hydrocarbons that are much less than static mass balance ones due to reservoir compartmentalization, and dramatic production changes due to changes in reservoir pressure as fractures close down as conduits. These often lead to reduced ultimate recoveries or higher production costs. Generally, modeling flow behavior and mass transport in fractured porous media is done using the dual-continuum concept in which fracture and matrix are modeled as two separate kinds of continua occupying the same control volume (element) in space. This type of numerical model cannot reproduce many commonly observed types of fractured reservoir behavior since they do not explicitly model the geometry of discrete fractures, solution features, and bedding that control flow pathway geometry. This inaccurate model of discrete feature connectivity results in inaccurate flow predictions in areas of the reservoir where there is not good well control. Discrete Fracture Networks (DFN) model has been developed to aid is solving some of these problems experienced by using the dual continuum models. The Discrete Fracture Networks (DFN) approach involves analysis and modeling which explicitly incorporates the geometry and properties of discrete features as a central component controlling flow and transport. DFN are stochastic models of fracture architecture that incorporate statistical scaling rules derived from analysis of fracture length, height, spacing, orientation, and aperture. This study is focused on developing a methodology for application of DFN to a shale gas reservoir and the practical application of DFN simulator (FracGen and NFflow) for fracture modeling of a shale gas reservoir and also studies the interaction of the different fracture properties on reservoir response. The most important results of the study are that a uniform fracture network distribution and fracture aperture produces the highest cumulative gas production for the different fracture networks and fracture/well properties considered.

Ogbechie, Joachim Nwabunwanne

2011-12-01T23:59:59.000Z

335

Brittle fracture phenomena: An hypothesis  

SciTech Connect

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

Britton, K.; Walton, O.R.

1987-05-01T23:59:59.000Z

336

Atomistic simulation of the hydrogen-induced fracture process in an iron-based superalloy  

DOE Green Energy (OSTI)

Austenitic superalloys exhibit dramatic reductions in ductility and crack growth resistance when high fugacity hydrogen and hydrogen-producing environments trigger a change in fracture mode from microvoid coalescence to slip band and intergranular fracture. Of particular importance is the change to intergranular fracture. We have therefore combined the Embedded Atom Method (EAM) with Monte Carlo simulations and molecular dynamics calculations to help define the effects of hydrogen on segregation and fracture at the atomic level. Nickel was used to simulate the face-centered-cubic austenite lattice while symmetric and asymmetric {sigma}9 tilt boundaries were used to simulate grain boundaries. These simulations show that grain boundaries are strong trap sites for hydrogen. They further show that hydrogen dramatically reduces the bond strength between atoms at grain boundary sites while inhibiting dislocation generation.

Moody, N.R.; Foiles, S.M.; Baskes, M.I. [Sandia National Labs., Livermore, CA (United States); Angelo, J.E. [Seagate, Bloomington, MN (United States)

1995-12-31T23:59:59.000Z

337

Incorporating Rigorous Height Determination into Unified Fracture Design  

E-Print Network (OSTI)

Hydraulic fracturing plays an important role in increasing production rate in tight reservoirs. The performance of the reservoir after fracturing can be observed from the productivity index. This parameter is dependent on the fracture geometry; height, length and width. Unified fracture design (UFD) offers a method to determine the fracture dimensions providing the maximum productivity index for a specific proppant amount. Then, in order to achieve the maximum productivity index, the treatment schedules including the amount of liquid and proppant used for each stage must be determined according to the fracture dimensions obtained from the UFD. The proppant number is necessary for determining the fracture geometry using the UFD. This number is used to find the maximum productivity index for a given proppant amount. Then, the dimensionless fracture conductivity index corresponding to the maximum productivity index can be computed. The penetration ration, the fracture length, and the propped fracture width can be computed from the dimensionless fracture conductivity. However, calculating the proppant number used in UFD requires the fracture height as an input. The most convenient way to estimate fracture height to input to the UFD is to assume that the fracture height is restricted by stress contrast between the pay zone and over and under-lying layers. In other words, the fracture height is assumed to be constant, independent of net pressure and equal to the thickness of the layer which has the least minimum principal stress. However, in reality, the fracture may grow out from the target formation and the height of fracture is dependent on the net pressure during the treatment. Therefore, it is necessary to couple determination of the fracture height with determination of the other fracture parameters. In this research, equilibrium height theory is applied to rigorously determine the height of fracture. Solving the problem iteratively, it is possible to incorporate the rigorous fracture height determination into the unified fracture design.

Pitakbunkate, Termpan

2010-08-01T23:59:59.000Z

338

CHARACTERIZATION OF IN-SITU STRESS AND PERMEABILITY IN FRACTURED RESERVOIRS  

Science Conference Proceedings (OSTI)

During the past six months we have adapted our 3-D elastic, anisotropic finite difference code by implementing the rotated staggered grid (RSG) method to more accurately represent large contrasts of elastic moduli between the fractures and surrounding formation, and applying the perfectly matched layer (PML) absorbing boundary condition to minimize boundary reflections. Two approaches for estimating fracture spacing from scattered seismic energy were developed. The first relates notches in the amplitude spectra of the scattered wavefield to the dominant fracture spacing that caused the scattering. The second uses conventional FK filtering to isolate the backscattered signals and then recovers an estimate of the fracture spacing from the dominant wavelength of those signals. Both methods were tested on synthetic data and then applied to the Emilio field data. The spectral notch method estimated the Emilio fracture spacing to be about 30 to 40 m, while the FK method found fracture spacing of about 48 to 53 m. We continue to work on two field data sets from fractured carbonate reservoirs provided by our industry sponsors--the offshore Emilio Field data (provided by ENIAGIP), and an onshore reservoir from the Middle East (provided by Shell). Calibration data in the form of well logs and previous fracture studies are available for both data sets. In previous reports we showed the spatial distribution fractures in the Emilio Field based on our calculated scattering index values. To improve these results we performed a map migration of all the scattering indices. The results of this migration process show a very strong correlation between the spatial distribution and orientation of our estimated fracture distribution and the fault system in the field. We observe that the scattering index clusters tend to congregate around the fault zones, particularly near multiple faults and at fault tips. We have also processed a swath of data from the second data set (the onshore carbonate field). FMI data are available from a number of wells for comparison to our seismic scattering analysis results. The agreement is very good, providing confidence that these methods can be applied to land seismic data that do not have the ideal azimuthal coverage.

Daniel R. Burns; M. Nafi Toksoz

2005-08-01T23:59:59.000Z

339

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

340

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

SciTech Connect

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

Costain, J.K.

2000-07-25T23:59:59.000Z

Note: This page contains sample records for the topic "highly fractured continuous" 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

Continuous Box game  

E-Print Network (OSTI)

The classical positional game Box was introduced by Chvátal and Erd?s in 1978 in their study of the biased connectivity game on the complete graph. Their analysis was subsequently extended by Hamidoune and Las Vergnas. The board of the Box game consists of elements of n disjoint sets (boxes), which might vary in size. The game is played by two players, Maker and Breaker. Maker claims m board elements per move whereas Breaker claims just one. Maker wins this game if and only if he claims all elements of some box by the end of the game. In this paper we introduce the game CBox, a continuous version of the Box game, where the sizes of the boxes need not be integral and in every move Maker puts a nonnegative real weight into each box, such that the weights sum up to the real number m. This new game, while closely related to the original Box game, turns out to be more amenable to analysis – we derive explicit and easy to use criteria for determining the winner in every instance of the game. Consequently, establishing a connection between CBox and Box, we also obtain applicable criteria for the Box game. 1

Dan Hefetz; Michael Krivelevich; Tibor Szabó

2011-01-01T23:59:59.000Z

342

Continuous production of conducting polymer  

E-Print Network (OSTI)

A device to continuously produce polypyrrole was designed, manufactured, and tested. Polypyrrole is a conducting polymer which has potential artificial muscle applications. The objective of continuous production was to ...

Gaige, Terry A. (Terry Alden), 1981-

2004-01-01T23:59:59.000Z

343

What is Continual Learning? | Department of Energy  

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

What is Continual Learning? What is Continual Learning? What is Continual Learning? November 25, 2013 - 3:56pm Addthis The purpose of Continual Learning is to improve the professional development of the federal workforce within the Department of Energy. In an effort to support this initiative, HC-20 offers 3 instructional workshops to assist employees and supervisors with employee development. These workshops are full of helpful tips and tricks for identifying low cost/no cost training, creating a high-quality IDP and assist supervisors with their responsibilities with employee development. The workshops will be offered either via adobe connect or classroom. Employees and supervisor are encouraged to attend these workshops and let us (HC-20) help you as we promote a learning culture.

344

Potential Contaminant Pathways from Hydraulically Fractured Shale to Aquifers  

E-Print Network (OSTI)

Potential Contaminant Pathways from Hydraulically Fractured Shale to Aquifers by Tom Myers Abstract Hydraulic fracturing of deep shale beds to develop natural gas has caused concern regarding the potential and preferential flow through fractures--could allow the transport of contaminants from the fractured shale

345

Does hydraulic-fracturing theory work in jointed rock masses  

DOE Green Energy (OSTI)

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

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

1983-01-01T23:59:59.000Z

346

Physical model of a fractured reservoir | Open Energy Information  

Open Energy Info (EERE)

model of a fractured reservoir model of a fractured reservoir Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: Physical model of a fractured reservoir Details Activities (1) Areas (1) Regions (0) Abstract: The objectives of the physical modeling effort are to: (1) evaluate injection-backflow testing for fractured reservoirs under conditions of known reservoir parameters (porosity, fracture width, etc.); (2) study the mechanisms controlling solute transport in fracture systems; and (3) provide data for validation of numerical models that explicitly simulate solute migration in fracture systems. The fracture network is 0.57-m wide, 1.7-m long, and consists of two sets of fractures at right angles to one another with a fracture spacing of 10.2 cm. A series of

347

Method of optimizing the conductivity of a propped fractured formation  

Science Conference Proceedings (OSTI)

This patent describes a method of reducing viscosity of a fracturing fluid containing proppant, a polymer, a delayed breaker and a nondelayed breaker, it comprises: introducing the fracturing fluid into a subterranean formation to form at least one fracture; depositing the proppant and the polymer in the fracture; determining an after closure polymer viscosity of the deposited polymer in the fracture; selecting a proppant pack permeability in the fracture; calculating an amount of breaker necessary to reduce the after closure viscosity of the deposited polymer to attain the selected permeability of; determining a minimum viscosity of the fracturing fluid which maintains the proppant in suspension in the fluid during pumping in the fracture; and introducing an effective amount of delayed breaker and nondelayed breaker into the fracturing fluid to attain the selected proppant pack permeability while maintaining the minimum viscosity to maintain the proppant in suspension in the fluid during pumping in the fracture.

Brannon, H.D.; Gulbis, J.; King, M.T.; Hawkins, G.W.

1992-04-14T23:59:59.000Z

348

A Study of Latrogenic Fracture Risk in Reduction of Pipkin Fracture ...  

Science Conference Proceedings (OSTI)

This study evaluated the risk of such fractures during closed reduction of Pipkin ... of Ti-6Al-4V for Medical Applications after Surface Modification by Anodization.

349

Geomechanical review of hydraulic fracturing technology  

E-Print Network (OSTI)

Hydraulic fracturing as a method for recovering unconventional shale gas has been around for several decades. Significant research and improvement in field methods have been documented in literature on the subject. The ...

Arop, Julius Bankong

2013-01-01T23:59:59.000Z

350

Studies of injection into naturally fractured reservoirs  

DOE Green Energy (OSTI)

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

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

1982-10-01T23:59:59.000Z

351

Definition: Hydraulic Fracturing | Open Energy Information  

Open Energy Info (EERE)

Jump to: navigation, search Dictionary.png Hydraulic Fracturing The process used in the Oil and Gas industry of drilling deep into the ground and injecting water, sand, and other...

352

Multiphase flow in fractured porous media  

Science Conference Proceedings (OSTI)

The major goal of this research project was to improve the understanding of the gas-oil two-phase flow in fractured porous media. In addition, miscible displacement was studied to evaluate its promise for enhanced recovery.

Firoozabadi, A.

1995-02-01T23:59:59.000Z

353

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

E-Print Network (OSTI)

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

Birkholzer, Jens T.; Zhang, Yingqi

2005-01-01T23:59:59.000Z

354

Hydraulic fracturing and propping tests at Yakedake field in Japan  

DOE Green Energy (OSTI)

Hydraulic fracturing experiments have been conducted at Yakedake field in Gifu prefecture, Japan. From the data obtained during the fracturing operation, the open-hole section permeability was estimated of the wellbore, the minimum pressure required to propagate the fracture, the impedances before and after the propping, and the earth stress normal to the fracture plane. The final fracture plane was also mapped with the microseismic events.

Yamaguchi, Tsutomu; Seo, Kunio; Suga, Shoto; Itoh, Toshinobu; Kuriyagawa, Michio

1984-01-01T23:59:59.000Z

355

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

SciTech Connect

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

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

2012-01-01T23:59:59.000Z

356

Sand control method employing special hydraulic fracturing technique  

SciTech Connect

A novel sand control method is disclosed wherein high viscosity, high sand concentration, fracturing fluids are pumped through sets of vertically oriented perforations in borehole casings located in unconsolidated or loosely consolidated pay zones. Various techniques are utilized to insure that sand fills disposed on either side of the borehole casing cover and substantially overlap each borehole casing perforation set. Procedures are then followed to bring the well into production without washing out the sand fills in these areas, whereby the resulting perforation-sand fill configurations effectively control sand production from the treated zone.

Medlin, W.L.; Mullins, L.D.; Zumwalt, G.L.

1983-04-05T23:59:59.000Z

357

Poroelastic response of orthotropic fractured porous media  

SciTech Connect

An algorithm is presented for inverting either laboratory or field poroelastic data for all the drained constants of an anisotropic (specifically orthotropic) fractured poroelastic system. While fractures normally weaken the system by increasing the mechanical compliance, any liquids present in these fractures are expected to increase the stiffness somewhat, thus negating to some extent the mechanical weakening influence of the fractures themselves. The analysis presented quantifies these effects and shows that the key physical variable needed to account for the pore-fluid effects is a factor of (1 - B), where B is Skempton's second coe#14;fficient and satisfies 0 {<=} #20; B < 1. This scalar factor uniformly reduces the increase in compliance due to the presence of communicating fractures, thereby stiffening the fractured composite medium by a predictable amount. One further goal of the discussion is to determine how many of the poroelastic constants need to be known by other means in order to determine the rest from remote measurements, such as seismic wave propagation data in the field. Quantitative examples arising in the analysis show that, if the fracture aspect ratio a{sub f} ~ 0.1 and the pore fluid is liquid water, then for several cases considered Skempton's B ~ 0:9, so the stiffening effect of the pore-liquid reduces the change in compliance due to the fractures by a factor 1-B ~ 0.1, in these examples. The results do however depend on the actual moduli of the unfractured elastic material, as well as on the pore-liquid bulk modulus, so these quantitative predictions are just examples, and should not be treated as universal results. Attention is also given to two previously unremarked poroelastic identities, both being useful variants of Gassmann's equations for homogeneous -- but anisotropic -- poroelasticity. Relationships to Skempton's analysis of saturated soils are also noted. The paper concludes with a discussion of alternative methods of analyzing and quantifying fluid-substitution behavior in poroelastic systems, especially for those systems having heterogeneous constitution.

Berryman, J.G.

2010-12-01T23:59:59.000Z

358

Estimating fracture parameters from p-wave velocity profiles about a geothermal well  

DOE Green Energy (OSTI)

The feasibility of locating fracture zones and estimating their crack parameters was examined using an areal well shoot method centered on Utah State Geothermal Well 9-1, Beaver County, Utah. High-resolution travel time measurements were made between a borehole sensor and an array of shot stations distributed radially and azimuthally about the well. Directional velocity behavior in the vicinity of the well was investigated by comparing velocity logs derived from the travel time data. Three fracture zones were identified form the velocity data, corroborating fracture indicators seen in other geophysical logs conducted in Well 9-1. Crack densities and average crack aspect ratios for these fracture zones were estimated using a self-consistent velocity theory (O'Connell and Budiansy 1974). Probable trends of these fracture zones were established from a combination of the data from the more distant shot stations and the results of a gravity survey. The results of this study indicate that the areal well shoot is a potentially powerful tool for the reconnaisance of fracture-controlled fluid and gas reservoirs. Improvements in methodology and hardware could transform it into an operationally viable survey method.

Jenkinson, J.T.; Henyey, T.L.; Sammis, C.G.; Leary, P.C.; McRaney, J.K.

1981-12-01T23:59:59.000Z

359

Candidate Well Selection for the Test of Degradable Biopolymer as Fracturing Fluid  

E-Print Network (OSTI)

Hydraulic fracturing is a well-established technology of generating highly conductive flow path inside the rock by injecting massive amount of fracturing fluid and proppant with sufficient pressure to break the formation apart. But as the concern for environment and health effects of hydraulic fracturing becomes intense, many efforts are made to replace the conventional fracturing fluid with more environment-friendly materials. The degradable biopolymer is one of the novel materials that is injected in the form of solid pellets containing proppant, degrades in the presence of water to form a viscous gel fluid, leaving no gel residue or harmful material. This work develops a methodology and computer program to determine the best candidate wells for the field test of degradable biopolymer as fracturing fluid. The unique properties of degradable biopolymer is captured in the selection of decision criteria such as bottomhole temperature and treatment volume as well as traditional hydraulic fracturing candidate well selection criteria such as formation permeability, productivity index.

Hwang, Yun Suk

2011-12-01T23:59:59.000Z

360

Flow of fracturing foams in vertical, horizontal and inclined pipes  

E-Print Network (OSTI)

Foams are complex mixtures of a gas and a liquid, with the latter being the continuous phase. The rheological properties of foams are strongly influenced by parameters like temperature, absolute pressure, foam quality, texture, foam-channel wall effects, liquid phase properties, and type and concentration of surfactant. The high solids carrying capacity, the minimum amount of fluid placed in the formation, and the excellent fluid recovery after treatment are some of the advantages that foam fluids present when used during fracturing operations. This thesis is a study of foam flow in pipes, the pressure calculations, the study of rheological properties and their evaluation. The objectives of this research are to: 1. Compare various rheological models representing foams. 2. Develop an algorithm that finds the rheological parameters for the different models at different pressures in the pipe. 3. Provide an engineer with a method that predicts pressure at one end, if pressure at the other end is known, given the rheological parameters of the fluid, the diameter of the pipe and the inlet stream properties. 4. Provide a spreadsheet program for different fluid models that calculates pressures in an inclined, vertical or horizontal pipe. 5. Validate the programs. General curve fitting techniques are used to fit different models: namely, power law, Bingham plastic and Herschel Bulkley models to shear stress vs. shear rate data. The trend of the power law and Bingham plastic rheological parameters with respect to quality is observed. A method to estimate the rheological parameters at different pressures along the pipe using regression methods is developed. Spreadsheet programs for power law Bingham plastic and volume equalized power law model have been developed, which calculate pressures in inclined, horizontal and vertical pipes. The methods for the power law and Bingham plastic fluids are iterative methods. The volume equalized power law program adopts the volume equalized principle, which uses mechanical energy balance with frictional losses calculated from a rheological model. The mechanical energy balance is integrated to obtain a non-linear equation containing the unknown pressure.

Krindinti, Kshipraprasad H

2002-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "highly fractured continuous" 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

Dry oxidation and fracture of LWR spent fuels  

SciTech Connect

This report evaluates the characteristics of oxidation and fracture of light-water reactor (LWR) spent fuel in dry air. It also discusses their effects on radionuclide releases in the anticipated high-level waste repository environment. A sphere model may describe diffusion-limited formation of lower oxides, such as U{sub 4}O{sub 9}, in the oxidation of the spent fuel (SF) matrix. Detrimental higher oxides, such as U{sub 3}O{sub 8}, may not form at temperatures below a threshold temperature. The nucleation process suggests that a threshold temperature exists. The calculated results regarding fracture properties of the SF matrix agree with experimental observations. Oxidation and fracture of Zircaloy may not be significant under anticipated conditions. Under saturated or unsaturated aqueous conditions, oxidation of the SF matrix is believed to increase the releases of Pu-(239+240), Am-(241+243), C-14, Tc-99, I-129, and Cs-135. Under dry conditions, I-129 releases are likely to be small, unlike C-14, in lower oxides; Cl-36, Tc-99, I-129, and Cs-135 may be released fast in higher oxides. 79 refs.

Ahn, T.M.

1996-11-01T23:59:59.000Z

362

LNG cascading damage study. Volume I, fracture testing report.  

SciTech Connect

As part of the liquefied natural gas (LNG) Cascading Damage Study, a series of structural tests were conducted to investigate the thermal induced fracture of steel plate structures. The thermal stresses were achieved by applying liquid nitrogen (LN{sub 2}) onto sections of each steel plate. In addition to inducing large thermal stresses, the lowering of the steel temperature simultaneously reduced the fracture toughness. Liquid nitrogen was used as a surrogate for LNG due to safety concerns and since the temperature of LN{sub 2} is similar (-190 C) to LNG (-161 C). The use of LN{sub 2} ensured that the tests could achieve cryogenic temperatures in the range an actual vessel would encounter during a LNG spill. There were four phases to this test series. Phase I was the initial exploratory stage, which was used to develop the testing process. In the Phase II series of tests, larger plates were used and tested until fracture. The plate sizes ranged from 4 ft square pieces to 6 ft square sections with thicknesses from 1/4 inches to 3/4 inches. This phase investigated the cooling rates on larger plates and the effect of different notch geometries (stress concentrations used to initiate brittle fracture). Phase II was divided into two sections, Phase II-A and Phase II-B. Phase II-A used standard A36 steel, while Phase II-B used marine grade steels. In Phase III, the test structures were significantly larger, in the range of 12 ft by 12 ft by 3 ft high. These structures were designed with more complex geometries to include features similar to those on LNG vessels. The final test phase, Phase IV, investigated differences in the heat transfer (cooling rates) between LNG and LN{sub 2}. All of the tests conducted in this study are used in subsequent parts of the LNG Cascading Damage Study, specifically the computational analyses.

Petti, Jason P.; Kalan, Robert J.

2011-12-01T23:59:59.000Z

363

Modeling interfacial fracture in Sierra.  

SciTech Connect

This report summarizes computational efforts to model interfacial fracture using cohesive zone models in the SIERRA/SolidMechanics (SIERRA/SM) finite element code. Cohesive surface elements were used to model crack initiation and propagation along predefined paths. Mesh convergence was observed with SIERRA/SM for numerous geometries. As the funding for this project came from the Advanced Simulation and Computing Verification and Validation (ASC V&V) focus area, considerable effort was spent performing verification and validation. Code verification was performed to compare code predictions to analytical solutions for simple three-element simulations as well as a higher-fidelity simulation of a double-cantilever beam. Parameter identification was conducted with Dakota using experimental results on asymmetric double-cantilever beam (ADCB) and end-notched-flexure (ENF) experiments conducted under Campaign-6 funding. Discretization convergence studies were also performed with respect to mesh size and time step and an optimization study was completed for mode II delamination using the ENF geometry. Throughout this verification process, numerous SIERRA/SM bugs were found and reported, all of which have been fixed, leading to over a 10-fold increase in convergence rates. Finally, mixed-mode flexure experiments were performed for validation. One of the unexplained issues encountered was material property variability for ostensibly the same composite material. Since the variability is not fully understood, it is difficult to accurately assess uncertainty when performing predictions.

Brown, Arthur A.; Ohashi, Yuki; Lu, Wei-Yang; Nelson, Stacy A. C.; Foulk, James W.,; Reedy, Earl David,; Austin, Kevin N.; Margolis, Stephen B.

2013-09-01T23:59:59.000Z

364

Identifying Fracture Types and Relative Ages Using Fluid Inclusion Stratigraphy  

DOE Green Energy (OSTI)

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

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

2008-06-30T23:59:59.000Z

365

(Continued on page 2) (Continued on page 2)  

E-Print Network (OSTI)

MAY 2009 (Continued on page 2) (Continued on page 2) WWW.RSMAS.MIAMI.EDU DEAN OTIS BROWN: A LEGACY of his decades of service and dedication to the University of Miami, Brown was awarded the UM Presidents in 2003, the University of Miami Presidents Medal honors individuals for their outstanding leadership

Miami, University of

366

Transport of Bottom Water in the Romanche Fracture Zone and the Chain Fracture Zone  

Science Conference Proceedings (OSTI)

Two moored arrays deployed in the Romanche Fracture Zone and Chain Fracture Zone in the equatorial Atlantic Ocean provide two-year-long time series of current and temperature in the Lower North Atlantic Deep Water and the Antarctic Bottom Water. ...

Herlé Mercier; Kevin G. Speer

1998-05-01T23:59:59.000Z

367

HYDRAULIC FRACTURING AND OVERCORING STRESS MEASUREMENTS IN A DEEP BOREHOLE AT THE STRIPA TEST MINE, SWEDEN  

E-Print Network (OSTI)

u l y 2 , 1 9 8 1 HYDRAULIC FRACTURING AND OVERCORING STRESSI nun LBL-12478 HYDRAULIC FRACTURING AND OVERCORING STRESSthe calculated stress. n HYDRAULIC FRACTURING EQUIPMENT AND

Doe, T.

2010-01-01T23:59:59.000Z

368

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

E-Print Network (OSTI)

Zimmermann, G. , 2005. Hydraulic fracturing in a sedimentaryare described in the hydraulic fracturing context, in whichoverview. However, hydraulic fracturing theories and related

Wessling, S.

2009-01-01T23:59:59.000Z

369

A STATISTICAL FRACTURE MECHANICS APPROACH TO THE STRENGTH OF BRITTLE ROCK  

E-Print Network (OSTI)

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

Ratigan, J.L.

2010-01-01T23:59:59.000Z

370

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

E-Print Network (OSTI)

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

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

2001-01-01T23:59:59.000Z

371

Introducing a Clinical Practice Guideline Using Early CT in the Diagnosis of Scaphoid and Other Fractures  

E-Print Network (OSTI)

61-6. 30. Kusano N. Diagnosis of Occult Scaphoid Fracture: AMJ, Schaefer-Prokop C, et al. Occult scaphoid fractures:revealing radiographically occult scaphoid fractures. [see

2009-01-01T23:59:59.000Z

372

Why continue the GEBA project?  

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

and subfamilies that could be useful to the DOE missions. Principal Investigators: Jonathan Eisen, DOE JGI Program: CSP 2011 Home > Sequencing > Why continue the GEBA project...

373

Development of experimental verification techniques for non-linear deformation and fracture on the nanometer scale.  

SciTech Connect

This work covers three distinct aspects of deformation and fracture during indentations. In particular, we develop an approach to verification of nanoindentation induced film fracture in hard film/soft substrate systems; we examine the ability to perform these experiments in harsh environments; we investigate the methods by which the resulting deformation from indentation can be quantified and correlated to computational simulations, and we examine the onset of plasticity during indentation testing. First, nanoindentation was utilized to induce fracture of brittle thin oxide films on compliant substrates. During the indentation, a load is applied and the penetration depth is continuously measured. A sudden discontinuity, indicative of film fracture, was observed upon the loading portion of the load-depth curve. The mechanical properties of thermally grown oxide films on various substrates were calculated using two different numerical methods. The first method utilized a plate bending approach by modeling the thin film as an axisymmetric circular plate on a compliant foundation. The second method measured the applied energy for fracture. The crack extension force and applied stress intensity at fracture was then determined from the energy measurements. Secondly, slip steps form on the free surface around indentations in most crystalline materials when dislocations reach the free surface. Analysis of these slip steps provides information about the deformation taking place in the material. Techniques have now been developed to allow for accurate and consistent measurement of slip steps and the effects of crystal orientation and tip geometry are characterized. These techniques will be described and compared to results from dislocation dynamics simulations.

Moody, Neville Reid; Bahr, David F.

2005-11-01T23:59:59.000Z

374

Naturally fractured tight gas: Gas reservoir detection optimization. Quarterly report, January 1--March 31, 1997  

SciTech Connect

Economically viable natural gas production from the low permeability Mesaverde Formation in the Piceance Basin, Colorado requires the presence of an intense set of open natural fractures. Establishing the regional presence and specific location of such natural fractures is the highest priority exploration goal in the Piceance and other western US tight, gas-centered basins. Recently, Advanced Resources International, Inc. (ARI) completed a field program at Rulison Field, Piceance Basin, to test and demonstrate the use of advanced seismic methods to locate and characterize natural fractures. This project began with a comprehensive review of the tectonic history, state of stress and fracture genesis of the basin. A high resolution aeromagnetic survey, interpreted satellite and SLAR imagery, and 400 line miles of 2-D seismic provided the foundation for the structural interpretation. The central feature of the program was the 4.5 square mile multi-azimuth 3-D seismic P-wave survey to locate natural fracture anomalies. The interpreted seismic attributes are being tested against a control data set of 27 wells. Additional wells are currently being drilled at Rulison, on close 40 acre spacings, to establish the productivity from the seismically observed fracture anomalies. A similar regional prospecting and seismic program is being considered for another part of the basin. The preliminary results indicate that detailed mapping of fault geometries and use of azimuthally defined seismic attributes exhibit close correlation with high productivity gas wells. The performance of the ten new wells, being drilled in the seismic grid in late 1996 and early 1997, will help demonstrate the reliability of this natural fracture detection and mapping technology.

NONE

1997-12-31T23:59:59.000Z

375

Sealed glass coating of high temperature ceramic superconductors  

DOE Patents (OSTI)

A method and article of manufacture of a lead oxide based glass coating on a high temperature superconductor is disclosed. The method includes preparing a dispersion of glass powders in a solution, applying the dispersion to the superconductor, drying the dispersion before applying another coating and heating the glass powder dispersion at temperatures below oxygen diffusion onset and above the glass melting point to form a continuous glass coating on the superconductor to establish compressive stresses which enhance the fracture strength of the superconductor. 8 figs.

Wu, W.; Chu, C.Y.; Goretta, K.C.; Routbort, J.L.

1995-05-02T23:59:59.000Z

376

Fracture detection and mapping for geothermal reservoir definition: an assessment of current technology, research, and research needs  

DOE Green Energy (OSTI)

The detection and mapping of fractures and other zones of high permeability, whether natural or manmade, has been a subject of considerable economic and scientific interest to the pertroleum industry and to the geothermal community. Research related to fractured geothermal reservoirs has been conducted under several past DOE geothermal energy development programs. In this paper we review the present state of technology in fracture detection and mapping. We outline the major problems and limitations of the ''conventional'' techniques, and current research in new technologies. We also present research needs.

Goldstein, N.E.

1984-11-01T23:59:59.000Z

377

Determining the 3-D fracture structure in the Geysers geothermal reservoir  

DOE Green Energy (OSTI)

The bulk of the steam at the Geysers geothermal field is produced from fractures in a relatively impermeable graywacke massif which has been heated by an underlying felsite intrusion. The largest of these fractures are steeply dipping right lateral strike-slip faults which are subparallel to the NW striking Collayomi and Mercuryville faults which form the NE and SW boundaries of the known reservoir. Where the graywacke source rock outcrops at the surface it is highly sheared and fractured over a wide range of scale lengths. Boreholes drilled into the reservoir rock encounter distinct ''steam entries'' at which the well head pressure jumps from a few to more than one hundred psi. This observation that steam is produced from a relatively small number of major fractures has persuaded some analysts to use the Warren and Root (1963) dual porosity model for reservoir simulation purposes. The largest fractures in this model are arranged in a regular 3-D array which partitions the reservoir into cubic ''matrix'' blocks. The net storage and transport contribution of all the smaller fractures in the reservoir are lumped into average values for the porosity and permeability of these matrix blocks which then feed the large fractures. Recent improvements of this model largely focus on a more accurate representation of the transport from matrix to fractures (e.g. Pruess et al., 1983; Ziminerman et al., 1992), but the basic geometry is rarely questioned. However, it has long been recognized that steam entries often occur in clusters separated by large intervals of unproductive rock (Thomas et al., 1981). Such clustering of fixtures at all scale lengths is one characteristic of self-similar distributions in which the fracture distribution is scale-independent. Recent studies of the geometry of fracture networks both in the laboratory and in the field are finding that such patterns are self-similar and can be best described using fractal geometry. Theoretical simulations of fracture development in heterogeneous media also produce fractal patterns. However, a physical interpretation of the mechanics which produce the observed fractal geometry remains an active area of current research. Two hypotheses for the physical cause of self-similarity are the Laplacian growth of fractures in a self-organized critical stress field, and the evolution of percolation clusters in a random medium. Each predicts a different, fractal dimension. The more important questions from a reservoir engineering point of view are: (1) is the network of fractures in the Geysers reservoir fractal and if so over what range of fracture sizes is the self-similarity observed and what is its fractal dimension, and (2) do the conventional dual porosity numerical simulation schemes provide an adequate description of flow and heat mining at the Geysers? Other papers in this volume by Acuna, Ershaghi, and Yortsos (1992) and Mukhopodhyoy and Sahimi (1992) address the second question. The primary objective of this paper is to try to answer the first. Toward this goal we have mapped fracture patterns in surface exposures of the graywacke source rock at the outcrop scale (meters), at the road-cut scale (tens of meters) and at the regional scale (kilometers). We have also examined cores collected at depth from the graywacke reservoir rocks, and analyzed drilling logs making use of the pattern of steam entries as well as the fluctuations in drilling rate.

Sammis, Charles G.; Linji An; Iraj Ershaghi

1992-01-01T23:59:59.000Z

378

HYDRAULIC FRACTURING AND INDUCED SEISMICITY IN KANSAS  

E-Print Network (OSTI)

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

unknown authors

2013-01-01T23:59:59.000Z

379

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

DOE Green Energy (OSTI)

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

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

1984-07-01T23:59:59.000Z

380

Discrete Fracture Network Models for Risk Assessment of Carbon Sequestration in Coal  

Science Conference Proceedings (OSTI)

A software package called DFNModeler has been developed to assess the potential risks associated with carbon sequestration in coal. Natural fractures provide the principal conduits for fluid flow in coal-bearing strata, and these fractures present the most tangible risks for the leakage of injected carbon dioxide. The objectives of this study were to develop discrete fracture network (DFN) modeling tools for risk assessment and to use these tools to assess risks in the Black Warrior Basin of Alabama, where coal-bearing strata have high potential for carbon sequestration and enhanced coalbed methane recovery. DFNModeler provides a user-friendly interface for the construction, visualization, and analysis of DFN models. DFNModeler employs an OpenGL graphics engine that enables real-time manipulation of DFN models. Analytical capabilities in DFNModeler include display of structural and hydrologic parameters, compartmentalization analysis, and fluid pathways analysis. DFN models can be exported to third-party software packages for flow modeling. DFN models were constructed to simulate fracturing in coal-bearing strata of the upper Pottsville Formation in the Black Warrior Basin. Outcrops and wireline cores were used to characterize fracture systems, which include joint systems, cleat systems, and fault-related shear fractures. DFN models were constructed to simulate jointing, cleating, faulting, and hydraulic fracturing. Analysis of DFN models indicates that strata-bound jointing compartmentalizes the Pottsville hydrologic system and helps protect shallow aquifers from injection operations at reservoir depth. Analysis of fault zones, however, suggests that faulting can facilitate cross-formational flow. For this reason, faults should be avoided when siting injection wells. DFN-based flow models constructed in TOUGH2 indicate that fracture aperture and connectivity are critical variables affecting the leakage of injected CO{sub 2} from coal. Highly transmissive joints near an injection well have potential to divert a large percentage of an injected CO{sub 2} stream away from a target coal seam. However, the strata-bound nature of Pottsville fracture systems is a natural factor that mitigates the risk of long-range leakage and surface seepage. Flow models indicate that cross-formational flow in strata-bound joint networks is low and is dissipated by about an order of magnitude at each successive bedding contact. These models help confirm that strata-bound joint networks are self-compartmentalizing and that the thick successions of interbedded shale and sandstone separating the Pottsville coal zones are confining units that protect shallow aquifers from injection operations at reservoir depth. DFN models are powerful tools for the simulation and analysis of fracture networks and can play an important role in the assessment of risks associated with carbon sequestration and enhanced coalbed methane recovery. Importantly, the stochastic nature DFN models dictates that they cannot be used to precisely reproduce reservoir conditions in a specific field area. Rather, these models are most useful for simulating the fundamental geometric and statistical properties of fracture networks. Because the specifics of fracture architecture in a given area can be uncertain, multiple realizations of DFN models and DFN-based flow models can help define variability that may be encountered during field operations. Using this type of approach, modelers can inform the risk assessment process by characterizing the types and variability of fracture architecture that may exist in geologic carbon sinks containing natural fractures.

Jack Pashin; Guohai Jin; Chunmiao Zheng; Song Chen; Marcella McIntyre

2008-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "highly fractured continuous" 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

Anomalous fracture-extension pressure in granitic rocks  

DOE Green Energy (OSTI)

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

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

1978-01-01T23:59:59.000Z

382

Fracture Characterization Technologies | Open Energy Information  

Open Energy Info (EERE)

Fracture Characterization Technologies Fracture Characterization Technologies Jump to: navigation, search Geothermal ARRA Funded Projects for Fracture Characterization Technologies Loading map... {"format":"googlemaps3","type":"ROADMAP","types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"limit":200,"offset":0,"link":"all","sort":[""],"order":[],"headers":"show","mainlabel":"","intro":"","outro":"","searchlabel":"\u2026 further results","default":"","geoservice":"google","zoom":false,"width":"600px","height":"350px","centre":false,"layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","icon":"","visitedicon":"","forceshow":true,"showtitle":true,"hidenamespace":false,"template":false,"title":"","label":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"locations":[{"text":"

383

Pressure transient analysis for naturally fractured reservoirs  

Science Conference Proceedings (OSTI)

New ideas are presented for the interpretation of pressure transient tests for wells in naturally fractured reservoirs. This work is based on the transient matrix flow model formulated by de Swaan. The differences between this model and the Warren and Root model occur during the transition flow period. It is demonstrated that the behavior of a naturally fractured reservoir can be correlated by using three dimensionless parameters. It is established that regardless of matrix geometry the transition period might exhibit a straight line whose slope is equal to half the slope of the classical parallel semilog straight lines, provided the transient matrix linear flow is present. In addition, information is provided on the estimation of fracture area per unit matrix volume or matrix parameters from the transition period semilog straight line. It is shown that matrix geometry might be identified when pressure data are smooth. Field examples are included to illustrate the application and the validity of the theoretical results of this study.

Cinco-ley, H.; Samaniego, F.V.

1982-09-01T23:59:59.000Z

384

Transient gas or liquid flow along a preexisting or hydraulically-induced fracture in a permeable medium  

DOE Green Energy (OSTI)

Similarity solutions are derived for the trasient two-dimensional flow of a gas or liquid along an isolated fracture in a permeable medium. The driving pressure at the fracture inlet is constant, and the confining stress is uniform. Two different cases are considered, pre-existing fractures with uniform aperture as well as hydraulic fractures with a variable aperture proportional to the local overpressure (fluid pressure less confining stress). The evolution of the pressure distribution is described by a set of four asymptotic solutions, each having a self-similar form. At early times the flow in the fracture is turbulent, and Darcian seepage losses into the porous surroundings are negligible. At late times the flow in the fracture is laminar, and seepage losses become a dominant consideration. At intermediate times there are two alternative asymptotes, depending upon physical parameters. The mathematical model also describe the flow along a fracture which is fulled with high-permeability porous material as well as the flow in an assemblage of porous blocks. 19 refs., 10 figs.

Nilson, R.H.; Morrison, F.A. Jr.

1985-05-01T23:59:59.000Z

385

Gas condensate damage in hydraulically fractured wells  

E-Print Network (OSTI)

This project is a research into the effect of gas condensate damage in hydraulically fractured wells. It is the result of a problem encountered in producing a low permeability formation from a well in South Texas owned by the El Paso Production Company. The well was producing from a gas condensate reservoir. Questions were raised about whether flowing bottomhole pressure below dewpoint would be appropriate. Condensate damage in the hydraulic fracture was expected to be of significant effect. In the most recent work done by Adedeji Ayoola Adeyeye, this subject was studied when the effects of reservoir depletion were minimized by introduction of an injector well with fluid composition the same as the original reservoir fluid. He also used an infinite conductivity hydraulic fracture along with a linear model as an adequate analogy. He concluded that the skin due to liquid build-up is not enough to prevent lower flowing bottomhole pressures from producing more gas. This current study investigated the condensate damage at the face of the hydraulic fracture in transient and boundary dominated periods when the effects of reservoir depletion are taken into account. As a first step, simulation of liquid flow into the fracture was performed using a 2D 1-phase simulator in order to help us to better understand the results of gas condensate simulation. Then during the research, gas condensate models with various gas compositions were simulated using a commercial simulator (CMG). The results of this research are a step forward in helping to improve the management of gas condensate reservoirs by understanding the mechanics of liquid build-up. It also provides methodology for quantifying the condensate damage that impairs linear flow of gas into the hydraulic fracture.

Reza, Rostami Ravari

2004-08-01T23:59:59.000Z

386

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

Science Conference Proceedings (OSTI)

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

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

1994-02-01T23:59:59.000Z

387

On equivalence of thinning fluids used for hydraulic fracturing  

E-Print Network (OSTI)

The paper aims to answer the question: if and how non-Newtonian fluids may be compared in their mechanical action when used for hydraulic fracturing? By employing the modified formulation of the PKN problem we obtain its simple analytical solutions in the cases of perfectly plastic and Newtonian fluids. Since the results for shear thinning fluids are intermediate between those for these cases, the obtained equation for the fracture length suggests a criterion of the equivalence of various shear thinning fluids for the problem of hydraulic fractures. We assume fluids equivalent in their hydrofracturing action, when at a reference time they produce fractures of the same length. The equation for the fracture length translates the equivalence in terms of the hydraulic fracture length and treatment time into the equivalence in terms of the properties of a fracturing fluid (behavior and consistency indices). Analysis shows that the influence of the consistency and behavior indices on the fracture length, particle v...

Linkov, Alexander

2012-01-01T23:59:59.000Z

388

How can we use one fracture to locate another?  

E-Print Network (OSTI)

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

Poliannikov, Oleg V.

2011-01-01T23:59:59.000Z

389

DOE's Shale Gas and Hydraulic Fracturing Research | Department...  

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

DOE's Shale Gas and Hydraulic Fracturing Research DOE's Shale Gas and Hydraulic Fracturing Research April 26, 2013 - 11:05am Addthis Statement of Guido DeHoratiis Acting Deputy...

390

Permeability Estimation From Velocity Anisotropy In Fractured Rock  

E-Print Network (OSTI)

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

Gibson, Richard L., Jr.

1990-01-01T23:59:59.000Z

391

Rigid-body fracture sound with precomputed soundbanks  

Science Conference Proceedings (OSTI)

We propose a physically based algorithm for synthesizing sounds synchronized with brittle fracture animations. Motivated by laboratory experiments, we approximate brittle fracture sounds using time-varying rigid-body sound models. We extend methods for ...

Changxi Zheng; Doug L. James

2010-07-01T23:59:59.000Z

392

Predicting the occurrence of open natural fractures in shale reservoirs  

SciTech Connect

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

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

1996-01-01T23:59:59.000Z

393

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

SciTech Connect

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

Huang, Hai; Plummer, Mitchell; Podgorney, Robert

2013-02-01T23:59:59.000Z

394

Diesel prices continue to decrease  

U.S. Energy Information Administration (EIA) Indexed Site

Diesel prices continue to decrease The U.S. average retail price for on-highway diesel fuel fell to 3.90 a gallon on Monday. That's down 1.3 cents from a week ago, based on the...

395

Diesel prices continue to increase  

U.S. Energy Information Administration (EIA) Indexed Site

Diesel prices continue to increase The U.S. average retail price for on-highway diesel fuel rose to 3.98 a gallon on Labor Day Monday. That's up 6.8 cents from a week ago, based...

396

Diesel prices continue to decrease  

U.S. Energy Information Administration (EIA) Indexed Site

Diesel prices continue to decrease The U.S. average retail price for on-highway diesel fuel fell to 3.92 a gallon on Monday. That's down 3 cents from a week ago based on the...

397

Diesel prices continue to increase  

U.S. Energy Information Administration (EIA) Indexed Site

Diesel prices continue to increase The U.S. average retail price for on-highway diesel fuel rose to 3.90 a gallon on Monday. That's up 3.6 cents from a week ago, based on the...

398

Diesel prices continue to decrease  

U.S. Energy Information Administration (EIA) Indexed Site

5, 2013 Diesel prices continue to decrease The U.S. average retail price for on-highway diesel fuel fell to 3.94 a gallon on Monday. That's down 3 12 cents from a week ago, based...

399

Diesel prices continue to decrease  

U.S. Energy Information Administration (EIA) Indexed Site

Diesel prices continue to decrease The U.S. average retail price for on-highway diesel fuel fell to 3.98 a gallon on Monday. That's down 1.6 cents from a week ago, based on the...

400

Diesel prices continue to decrease  

U.S. Energy Information Administration (EIA) Indexed Site

Diesel prices continue to decrease The U.S. average retail price for on-highway diesel fuel fell to 3.89 a gallon on Monday. That's down 1.1 cents from a week ago based on the...

Note: This page contains sample records for the topic "highly fractured continuous" 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

Diesel prices continue to decrease  

U.S. Energy Information Administration (EIA) Indexed Site

Diesel prices continue to decrease The U.S. average retail price for on-highway diesel fuel fell to 3.89 a gallon on Monday. That's down 5 12 cents from a week ago, based on the...

402

Diesel prices continue to decrease  

U.S. Energy Information Administration (EIA) Indexed Site

Diesel prices continue to decrease The U.S. average retail price for on-highway diesel fuel fell to 4.01 a gallon on Monday. That's down 4.1 cents from a week ago, based on the...

403

Diesel prices continue to increase  

U.S. Energy Information Administration (EIA) Indexed Site

Diesel prices continue to increase The U.S. average retail price for on-highway diesel fuel rose to 3.87 a gallon on Monday. That's up 3.9 cents from a week ago, based on the...

404

Diesel prices continue to increase  

U.S. Energy Information Administration (EIA) Indexed Site

Diesel prices continue to increase The U.S. average retail price for on-highway diesel fuel rose to 3.92 a gallon on Monday. That's up 1.2 cents from a week ago, based on the...

405

Diesel prices continue to increase  

U.S. Energy Information Administration (EIA) Indexed Site

Diesel prices continue to increase The U.S. average retail price for on-highway diesel fuel rose to 3.89 a gallon on Monday. That's up 2.4 cents from a week ago, based on the...

406

Diesel prices continue to decrease  

U.S. Energy Information Administration (EIA) Indexed Site

Diesel prices continue to decrease The U.S. average retail price for on-highway diesel fuel fell to 3.82 a gallon on Monday. That's down a penny from a week ago, based on the...

407

Diesel prices continue to decrease  

U.S. Energy Information Administration (EIA) Indexed Site

Diesel prices continue to decrease The U.S. average retail price for on-highway diesel fuel fell to 3.83 a gallon on Monday. That's down 2 cents from a week ago, based on the...

408

Diesel prices continue to increase  

U.S. Energy Information Administration (EIA) Indexed Site

Diesel prices continue to increase The U.S. average retail price for on-highway diesel fuel rose to 3.88 a gallon on Monday. That's up 3.9 cents from a week ago, based on the...

409

Diesel prices continue to decrease  

U.S. Energy Information Administration (EIA) Indexed Site

4, 2013 Diesel prices continue to decrease The U.S. average retail price for on-highway diesel fuel fell to 3.86 a gallon on Monday. That's down 1.3 cents from a week ago, based...

410

Fatigue and Fracture Toughness 3  

Science Conference Proceedings (OSTI)

Jun 6, 2012 ... Elimination of inactive rheologically supporting steel cores in overhead line conductors and replacing them with highly resistant AlMgSi alloy ...

411

Imaging, Characterizing, and Modeling of Fracture Networks and...  

Open Energy Info (EERE)

Los Alamos National Laboratory Other Principal Investigators Grant Bromhal, National Energy Technology Laboratory Targets Milestones - Improve image resolution for fracture...

412

Fluid Flow in Fractured Rock: Theory and Application  

E-Print Network (OSTI)

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

Long, J.C.S.

2012-01-01T23:59:59.000Z

413

Fracture Criterion of Discontinuous Carbon Fiber Dispersed SiC ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2012. Symposium, Ceramic Matrix Composites. Presentation Title, Fracture Criterion of ...

414

Towards Understanding the Deformation and Fracture Behavior of ...  

Science Conference Proceedings (OSTI)

Presentation Title, Towards Understanding the Deformation and Fracture Behavior of Gas Turbine Structural Materials at Elevated Temperatures. Author(s)  ...

415

Experimental and Analytical Research on Fracture Processes in ROck  

DOE Green Energy (OSTI)

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

Herbert H.. Einstein; Jay Miller; Bruno Silva

2009-02-27T23:59:59.000Z

416

Fan Blade Fracture in a Welded Assembly - Programmaster.org  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2013. Symposium, Failure Analysis and Prevention. Presentation Title, Fan Blade Fracture in a ...

417

Fracture and Delamination in Thin Film Si Electrodes  

Science Conference Proceedings (OSTI)

Symposium, Nanostructured Materials for Lithium Ion Batteries and for Supercapacitors. Presentation Title, Fracture and Delamination in Thin Film Si Electrodes.

418

LANL continuity of operations plan  

SciTech Connect

The Los Alamos National Laboratory (LANL) is a premier national security research institution, delivering scientific and engineering solutions for the nation's most crucial and complex problems. Our primary responsibility is to ensure the safety, security, and reliability of the nation's nuclear stockpile. LANL emphasizes worker safety, effective operational safeguards and security, and environmental stewardship, outstanding science remains the foundation of work at the Laboratory. In addition to supporting the Laboratory's core national security mission, our work advances bioscience, chemistry, computer science, earth and environmental sciences, materials science, and physics disciplines. To accomplish LANL's mission, we must ensure that the Laboratory EFs continue to be performed during a continuity event, including localized acts of nature, accidents, technological or attack-related emergencies, and pandemic or epidemic events. The LANL Continuity of Operations (COOP) Plan documents the overall LANL COOP Program and provides the operational framework to implement continuity policies, requirements, and responsibilities at LANL, as required by DOE 0 150.1, Continuity Programs, May 2008. LANL must maintain its ability to perform the nation's PMEFs, which are: (1) maintain the safety and security of nuclear materials in the DOE Complex at fixed sites and in transit; (2) respond to a nuclear incident, both domestically and internationally, caused by terrorist activity, natural disaster, or accident, including mobilizing the resources to support these efforts; and (3) support the nation's energy infrastructure. This plan supports Continuity of Operations for Los Alamos National Laboratory (LANL). This plan issues LANL policy as directed by the DOE 0 150.1, Continuity Programs, and provides direction for the orderly continuation of LANL EFs for 30 days of closure or 60 days for a pandemic/epidemic event. Initiation of COOP operations may be required to support an allhazards event, including a national security emergency, major fire, catastrophic natural disaster, man-made disaster, terrorism event, or technological disaster by rendering LANL buildings, infrastructure, or Technical Areas unsafe, temporarily unusable, or inaccessible.

Senutovitch, Diane M [Los Alamos National Laboratory

2010-12-22T23:59:59.000Z

419

Visualization and simulation of immiscible displacement in fractured systems using micromodels: Steam injection  

SciTech Connect

A study of steam and hot water injection processes in micromodel geometries that mimic a matrix-fracture system was undertaken. The followings were observed: Light components existing in the crude oil generated a very high efficient gas-drive at elevated temperatures. This gas generation in conjunction with natural surfactant existing in the crude oil, lead to the formation of a foam in the fracture and to improved displacement in the matrix. We observed that the steam enters the fracture and the matrix depending on whether the steam rate exceeds or not the critical values. The resulting condensed water also moves preferentially into the matrix or the fracture depending on the corresponding capillary number. Since steam is a non-wetting phase as a vapor, but becomes a wetting phase when condensed in a water-wet system, steam injection involves both drainage and imbibition. It was found that all of the oil trapped by the condensed water can be mobilized and recovered when in contact with steam. We also examined hot-water displacement. In comparison with cold-water experiments at the same capillary number, a higher sweep efficiency for both light and heavy oils was observed. It was found that the loam generated in the fracture during hot-water injection, is more stable than in steamflooding. Nonetheless, hot-water injection resulted into less efficient displacement in its absence.

Yortsos, Y.C.

1995-07-01T23:59:59.000Z

420

Naturally fractured tight gas reservoir detection optimization. Annual report, September 1993--September 1994  

Science Conference Proceedings (OSTI)

This report is an annual summarization of an ongoing research in the field of modeling and detecting naturally fractured gas reservoirs. The current research is in the Piceance basin of Western Colorado. The aim is to use existing information to determine the most optimal zone or area of fracturing using a unique reaction-transport-mechanical (RTM) numerical basin model. The RTM model will then subsequently help map subsurface lateral and vertical fracture geometries. The base collection techniques include in-situ fracture data, remote sensing, aeromagnetics, 2-D seismic, and regional geologic interpretations. Once identified, high resolution airborne and spaceborne imagery will be used to verify the RTM model by comparing surficial fractures. If this imagery agrees with the model data, then a further investigation using a three-dimensional seismic survey component will be added. This report presents an overview of the Piceance Creek basin and then reviews work in the Parachute and Rulison fields and the results of the RTM models in these fields.

NONE

1994-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "highly fractured continuous" 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.