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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.


1

Finding Large Aperture Fractures in Geothermal Resource Areas...  

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

Seismic Survey DOE Geothermal Peer Review 2010 - Presentation. Project summary: Drilling into large aperture open fractures (LAFs) typically yield production wells with...

2

Finding Large Aperture Fractures in Geothermal Resource Areas...  

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

3-D mapping of Large Aperture Fractures (LAF's) * Budget: 679,000 - Phase 2: Drilling - January-December, 2011. * Task 4: Stepout drilling from existing production wells....

3

Finding Large Aperture Fractures in Geothermal Resource Areas...  

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

A Three-Component Long-Offset Surface Seismic Survey, PSInSAR, and Kinematic Analysis Finding Large Aperture Fractures in Geothermal Resource Areas Using A Three-Component...

4

Finding Large Aperture Fractures in Geothermal Resource Areas Using A Three-Component Long-Offset Surface Seismic Survey, PSInSAR, and Kinematic Analysis  

Broader source: Energy.gov [DOE]

Fining Large Aperture Fractures in Geothermal Resource Areas Using A Three-Component Long-Offset Surface Seismic Survey, PSInSAR, and Kinematic Analysis presentation at the April 2013 peer review meeting held in Denver, Colorado.

5

LARGE-APERTURE D- ACCELERATORS  

E-Print Network [OSTI]

Vignetted current profile at accelerator entrance aperture 'LARGE-APERTURE D" ACCELERATORS* 0. A. Anderson" " Lawrencen i a 9-1720 Abstract Accelerator designs are described for

Anderson, O.A.

2010-01-01T23:59:59.000Z

6

Fracture aperture reconstruction and determination of hydrological properties: a  

E-Print Network [OSTI]

Fracture aperture reconstruction and determination of hydrological properties: a case study for fracture aperture reconstruction. The rst one is a correlation technique that estimates the normal aper techniques are applied to discontinuities extracted from a core drilled down to 20 m in a fractured marl

Toussaint, Renaud

7

Large aperture diffractive space telescope  

DOE Patents [OSTI]

A large (10's of meters) aperture space telescope including two separate spacecraft--an optical primary objective lens functioning as a magnifying glass and an optical secondary functioning as an eyepiece. The spacecraft are spaced up to several kilometers apart with the eyepiece directly behind the magnifying glass "aiming" at an intended target with their relative orientation determining the optical axis of the telescope and hence the targets being observed. The objective lens includes a very large-aperture, very-thin-membrane, diffractive lens, e.g., a Fresnel lens, which intercepts incoming light over its full aperture and focuses it towards the eyepiece. The eyepiece has a much smaller, meter-scale aperture and is designed to move along the focal surface of the objective lens, gathering up the incoming light and converting it to high quality images. The positions of the two space craft are controlled both to maintain a good optical focus and to point at desired targets which may be either earth bound or celestial.

Hyde, Roderick A. (Livermore, CA)

2001-01-01T23:59:59.000Z

8

The Large Aperture GRB Observatory  

E-Print Network [OSTI]

The Large Aperture GRB Observatory (LAGO) is aiming at the detection of the high energy (around 100 GeV) component of Gamma Ray Bursts, using the single particle technique in arrays of Water Cherenkov Detectors (WCD) in high mountain sites (Chacaltaya, Bolivia, 5300 m a.s.l., Pico Espejo, Venezuela, 4750 m a.s.l., Sierra Negra, Mexico, 4650 m a.s.l). WCD at high altitude offer a unique possibility of detecting low gamma fluxes in the 10 GeV - 1 TeV range. The status of the Observatory and data collected from 2007 to date will be presented.

Allard, D; Asorey, H; Barros, H; Bertou, X; Castillo, M; Chirinos, J M; De Castro, A; Flores, S; González, J; Berisso, M Gomez; Grajales, J; Guada, C; Day, W R Guevara; Ishitsuka, J; López, J A; Martínez, O; Melfo, A; Meza, E; Loza, P Miranda; Barbosa, E Moreno; Murrugarra, C; Núñez, L A; Ormachea, L J Otiniano; Pérez, G; Perez, Y; Ponce, E; Quispe, J; Quintero, C; Rivera, H; Rosales, M; Rovero, A C; Saavedra, O; Salazar, H; Tello, J C; Peralda, R Ticona; Varela, E; Velarde, A; Villaseñor, L; Wahl, D; Zamalloa, M A

2009-01-01T23:59:59.000Z

9

Very Large Aperture Diffractive Space Telescope  

SciTech Connect (OSTI)

A very large (10's of meters) aperture space telescope including two separate spacecraft--an optical primary functioning as a magnifying glass and an optical secondary functioning as an eyepiece. The spacecraft are spaced up to several kilometers apart with the eyepiece directly behind the magnifying glass ''aiming'' at an intended target with their relative orientation determining the optical axis of the telescope and hence the targets being observed. The magnifying glass includes a very large-aperture, very-thin-membrane, diffractive lens, e.g., a Fresnel lens, which intercepts incoming light over its full aperture and focuses it towards the eyepiece. The eyepiece has a much smaller, meter-scale aperture and is designed to move along the focal surface of the magnifying glass, gathering up the incoming light and converting it to high quality images. The positions of the two space craft are controlled both to maintain a good optical focus and to point at desired targets.

Hyde, Roderick Allen

1998-04-20T23:59:59.000Z

10

Constraints on flow regimes in wide-aperture fractures  

SciTech Connect (OSTI)

In recent years, significant advances have been made in our understanding of the complex flow processes in individual fractures, aided by flow visualization experiments and conceptual modeling efforts. These advances have led to the recognition of several flow regimes in individual fractures subjected to different initial and boundary conditions. Of these, the most important regimes are film flow, rivulet flow, and sliding of droplets. The existence of such significantly dissimilar flow regimes has been a major hindrance in the development of self-consistent conceptual models of flow for single fractures that encompass all the flow regimes. The objective of this study is to delineate the existence of the different flow regimes in individual fractures. For steady-state flow conditions, we developed physical constraints on the different flow regimes that satisfy minimum energy configurations, which enabled us to segregate the wide range of fracture transmissivity (volumetric flow rate per fracture width) into several flow regimes. These are, in increasing order of flow rate, flow of adsorbed films, flow of sliding drops, rivulet flow, stable film flow, and unstable (turbulent) film flow. The scope of this study is limited to wide-aperture fractures with the flow on the opposing sides of fracture being independent.

Ghezzehei, Teamrat A.

2004-02-28T23:59:59.000Z

11

High-resolution fracture aperture mapping using optical profilometry Pasha Ameli,1  

E-Print Network [OSTI]

High-resolution fracture aperture mapping using optical profilometry Pasha Ameli,1 Jean E. Elkhoury] Fractures play an important role in the Earth's crust, often controlling both mechanical and transport of fracture surfaces and the contacts and void spaces between fracture surfaces at high spatial resolution (10

Elkhoury, Jean

12

Measurement of fracture aperture fields using transmitted light: An evaluation of measurement errors and their influence on  

E-Print Network [OSTI]

Measurement of fracture aperture fields using transmitted light: An evaluation of measurement errors and their influence on simulations of flow and transport through a single fracture Russell L in fractures can be greatly enhanced through experimentation in transparent systems (analogs or replicas) where

Detwiler, Russell

13

The Balloon-borne Large Aperture Sub-millimetre Telescope  

E-Print Network [OSTI]

The Balloon-borne Large-Aperture Sub-millimetre Telescope (BLAST) will operate on a Long Duration Balloon platform with large format bolometer arrays at 250, 350 and 500 microns, initially using a 2m mirror, with plans to increase to 2.5m. BLAST is a collaboration between scientists in the USA, Canada, UK, Italy and Mexico. Funding has been approved and it is now in its building phase. The test flight is scheduled for 2002, with the first long duration flight the following year. The scientific goals are to learn about the nature of distant extragalactic star forming galaxies and cold pre-stellar sources by making deep maps both at high and low galactic latitudes. BLAST will be useful for planning Herschel key projects which use SPIRE.

Douglas Scott; the BLAST Team

2001-04-03T23:59:59.000Z

14

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

SciTech Connect (OSTI)

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

Detwiler, Russell

2014-04-30T23:59:59.000Z

15

E-Print Network 3.0 - advanced technology large-aperture Sample...  

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

(Advanced Photonix). These diodes were chosen for two reasons. First... pulsed terahertz emitter, a large-aperture GaAs photoconductive switch, is carried out. It is...

16

Design considerations for a large aperture high field superconducting dipole  

SciTech Connect (OSTI)

The final phase of the Fermilab upgrade proposal calls for a new ring of superconducting magnets to be placed in the existing Main Accelerator tunnel. The goal of this design study is to specify a high field dipole (HFD) that is capable of supporting fixed target operation (ramping, resonant extraction) at a field of 6.6T (1.5 Tev) and colliding beam physics at 8.0T (1.8 Tev). The magnetic field quality at high field is set by the large amplitude orbits associated with resonant extraction. The field quality must therefore be at least as good as the existing Tevatron magnets which fulfill these criteria. The high fields and large aperture of this magnet result in large forces on the coil and collar assemblies. Therefore, the cold mass design must be able to sustain these forces while providing sufficient cooling to the coils during 4.2 K fixed target operation, and a minimum heat load during 1.8 K collider operation. The design work is still in progress but a cosine-theta, cold-iron dipole with a 70mm inner diameter coil has been tentatively adopted. This report presents details on the conductor and cable parameters, coil cross-section, projected manufacturing tolerances, iron yoke design, and cold mass assembly. 4 refs., 5 figs., 1 tab.

Harfoush, F.; Ankenbrandt, C.; Harrison, M.; Kerby, J.; Koepke, K.; Mantsch, P.; Nicol, T.; Riddiford, A.; Theilacker, J.

1989-03-01T23:59:59.000Z

17

The role of the solvent viscosity on the spatiotemporal instabilities of large aperture dye lasers  

E-Print Network [OSTI]

The role of the solvent viscosity on the spatiotemporal instabilities of large aperture dye lasers for publication 27 May 1998 Local intensity fluctuations in a large aperture dye laser have been measured of Physics. S0003-6951 98 00131-4 High energy flash-lamp pumped dye lasers are charac- terized by a large

Rey Juan Carlos, Universidad

18

LAGOVirtual: A Collaborative Environment for the Large Aperture GRB Observatory  

E-Print Network [OSTI]

We present the LAGOVirtual Project: an ongoing project to develop platform to collaborate in the Large Aperture GRB Observatory (LAGO). This continental-wide observatory is devised to detect high energy (around 100 GeV) component of Gamma Ray Bursts, by using the single particle technique in arrays of Water Cherenkov Detectors (WCD) at high mountain sites (Chacaltaya, Bolivia, 5300 m a.s.l., Pico Espejo, Venezuela, 4750 m a.s.l., Sierra Negra, Mexico, 4650 m a.s.l). This platform will allow LAGO collaboration to share data, and computer resources through its different sites. This environment has the possibility to generate synthetic data by simulating the showers through AIRES application and to store/preserve distributed data files collected by the WCD at the LAGO sites. The present article concerns the implementation of a prototype of LAGO-DR adapting DSpace, with a hierarchical structure (i.e. country, institution, followed by collections that contain the metadata and data files), for the captured/simulate...

Camacho, R; Diaz, G; Guada, C; Hamar, V; Hoeger, H; Melfo, A; Nunez, L A; Perez, Y; Quintero, C; Rosales, M; Torrens, R

2009-01-01T23:59:59.000Z

19

LAGOVirtual: A Collaborative Environment for the Large Aperture GRB Observatory  

E-Print Network [OSTI]

We present the LAGOVirtual Project: an ongoing project to develop platform to collaborate in the Large Aperture GRB Observatory (LAGO). This continental-wide observatory is devised to detect high energy (around 100 GeV) component of Gamma Ray Bursts, by using the single particle technique in arrays of Water Cherenkov Detectors (WCD) at high mountain sites (Chacaltaya, Bolivia, 5300 m a.s.l., Pico Espejo, Venezuela, 4750 m a.s.l., Sierra Negra, Mexico, 4650 m a.s.l). This platform will allow LAGO collaboration to share data, and computer resources through its different sites. This environment has the possibility to generate synthetic data by simulating the showers through AIRES application and to store/preserve distributed data files collected by the WCD at the LAGO sites. The present article concerns the implementation of a prototype of LAGO-DR adapting DSpace, with a hierarchical structure (i.e. country, institution, followed by collections that contain the metadata and data files), for the captured/simulated data. This structure was generated by using the community, sub-community, collection, item model; available at the DSpace software. Each member institution-country of the project has the appropriate permissions on the system to publish information (descriptive metadata and associated data files). The platform can also associate multiple files to each item of data (data from the instruments, graphics, postprocessed-data, etc.).

R. Camacho; R. Chacon; G. Diaz; C. Guada; V. Hamar; H. Hoeger; A. Melfo; L. A. Nunez; Y. Perez; C. Quintero; M. Rosales; R. Torrens; the LAGO Collaboration

2009-12-12T23:59:59.000Z

20

The role of the molecular dynamics in the local intensity instabilities of large aperture dye lasers  

E-Print Network [OSTI]

The role of the molecular dynamics in the local intensity instabilities of large aperture dye fluctuations of large aperture dye lasers, and find dependencies on solvent viscosity and active molecular size dye lasers are used in a great deal of practical applications, from isotope enrichment to photody

Rey Juan Carlos, Universidad

Note: This page contains sample records for the topic "large aperture fractures" 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

Effective Aperture of a Large Pseudorandom Low-Frequency  

E-Print Network [OSTI]

(LWA) LWA Station State of New Mexico, USA Aperture synthesis radio telescope · About 50 "stations" across New Mexico · Each station is an array of many elements · 20 - 80 MHz (at least) Project Status 16.6562 for Realistic = 3.0 in E-Plane = 0.5 in H-Plane [m2] Crude Estimate for Single Stand #12;8 Effective Aperture

Ellingson, Steven W.

22

Finding Large Aperture Fractures in Geothermal Resource Areas...  

Open Energy Info (EERE)

-Significantly reduced number of dry holes, fewer wells drilled and higher per-well productivity for a given wellfield power output -Significantly reduce parasitic loads for...

23

Finding Large Aperture Fractures in Geothermal Resource Areas...  

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

in well siting. - Definitive well test with rig on hole. - Real time geologic, PT logging, and flowtest analysis to determine next rig move. No standby or demob cost. -...

24

Finding Large Aperture Fractures in Geothermal Resource Areas Using A  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeat PumpRecordFederal Registry CommentsOverview » FinancingEnergy

25

Finding Large Aperture Fractures in Geothermal Resource Areas Using a  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeat PumpRecordFederal Registry CommentsOverview » FinancingEnergyThree-Component

26

Finding Large Aperture Fractures in Geothermal Resource Areas Using a  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 NoPublicIDAPowerPlantSitingConstruction.pdfNotify98.pdf Jump to:Siting.pdf Jump to:NoticeFinanzas Carbono

27

Hydraulic transmissivity and heat exchange efficiency of open fractures: a model based on lowpass filtered apertures  

E-Print Network [OSTI]

Natural open joints in rocks commonly present multi-scale self-affine apertures. This geometrical complexity affects fluid transport and heat exchange between the flow- ing fluid and the surrounding rock. In particular, long range correlations of self-affine apertures induce strong channeling of the flow which influences both mass and heat advection. A key question is to find a geometrical model of the complex aperture that describes at best the macroscopic properties (hydraulic conductivity, heat exchange) with the smallest number of parameters. Solving numerically the Stokes and heat equa- tions with a lubrication approximation, we show that a low pass filtering of the aperture geometry provides efficient estimates of the effective hydraulic and thermal properties (apertures). A detailed study of the influence of the bandwidth of the lowpass filtering on these transport properties is also performed. For instance, keeping the information of amplitude only of the largest Fourier length scales allows us to rea...

Neuville, Amélie; Schmittbuhl, Jean; 10.1111/j.1365-246X.2011.05126.x

2011-01-01T23:59:59.000Z

28

Low permeability gas reservoir production using large hydraulic fractures  

E-Print Network [OSTI]

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

Holditch, Stephen A

1970-01-01T23:59:59.000Z

29

Design of large aperture superferric quadrupole magnets for an in-flight fragment separator  

SciTech Connect (OSTI)

Superferric quadrupole magnets to be used for in-flight fragment separator have been designed. A quadrupole magnet triplet for beam focusing is placed in a cryostat together with superconducting correction coils. To maximize acceptance of rare isotope beams produced by projectile fragmentation, it is essential to use large-aperture quadrupole magnets. The pole tip radius is 17 cm in the current design, and we tried to enlarge the aperture with 3D analysis on magnetic fields. In the front end of the separator, where a target and beam dump are located, we plan to use two sets of quadrupole triplets made of high-Tc superconductor (HTS) operating at 20-50 K considering high radiation heat load. The HTS magnet will use warm iron poles. Both low-Tc and high-Tc superconductors are acquired for test winding, and two kinds of dewar and cryostat are under construction to perform the coil and magnet tests. The magnetic design of superferric quadrupole is mainly discussed.

Zaghloul, Aziz; Kim, Dogyun; Kim, Jangyoul; Kim, Mijung; Kim, Myeongjin; Yun, Chongcheoul; Kim, Jongwon [Rare Isotope Science Project, Institute for Basic Science, Yuseong, Daejeon, 305-811 (Korea, Republic of)

2014-01-29T23:59:59.000Z

30

Operating Water Cherenkov Detectors in high altitude sites for the Large Aperture GRB Observatory  

E-Print Network [OSTI]

Water Cherenkov Detectors (WCD) are efficient detectors for detecting GRBs in the 10 GeV - 1 TeV energy range using the single particle technique, given their sensitivity to low energy secondary photons produced by high energy photons when cascading in the atmosphere. The Large Aperture GRB Observatory (LAGO) operates arrays of WCD in high altitude sites (above 4500 m a.s.l.) in Bolivia, Mexico and Venezuela, with planned extension to Peru. Details on the operation and stability of these WCD in remote sites with high background rates of particles will be detailed, and compared to simulations. Specific issues due to operation at high altitude, atmospheric effects and solar activity, as well as possible hardware enhancements will also be presented.

Allard, D; Asorey, H; Barros, H; Bertou, X; Castillo, M; Chirinos, J M; De Castro, A; Flores, S; González, J; Berisso, M Gomez; Grajales, J; Guada, C; Day, W R Guevara; Ishitsuka, J; López, J A; Martínez, O; Melfo, A; Meza, E; Loza, P Miranda; Barbosa, E Moreno; Murrugarra, C; Núñez, L A; Ormachea, L J Otiniano; Pérez, G; Perez, Y; Ponce, E; Quispe, J; Quintero, C; Rivera, H; Rosales, M; Rovero, A C; Saavedra, O; Salazar, H; Tello, J C; Peralda, R Ticona; Varela, E; Velarde, A; Villaseñor, L; Wahl, D; Zamalloa, M A

2009-01-01T23:59:59.000Z

31

Fracture-Flow-Enhanced Solute Diffusion into Fractured Rock  

E-Print Network [OSTI]

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

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

2008-01-01T23:59:59.000Z

32

A New Type of X-ray Condenser Lenses with Large Apertures Fabricated by Rolling of Structured Films  

SciTech Connect (OSTI)

In order to meet the demand for X-ray lenses with large apertures and, hence, photon flux, a new type of X-ray lenses has been developed: Rolled prismatic X-ray lenses feature a vast number of refracting surfaces to increase transparency and aperture, respectively. Prototypes of such lenses have been fabricated by molding and rolling of a structured polyimide film. In this work, rolled prismatic X-ray lenses are pictured, and results of first tests performed at the ANKA storage ring in Karlsruhe are presented.

Simon, M.; Reznikova, E.; Nazmov, V.; Grund, T. [Institut fuer Mikrostrukturtechnik, Forschungszentrum Karlsruhe GmbH Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Last, A. [Institut fuer Mikrostrukturtechnik, Universitaet Karlsruhe Kaiserstrasse 12, 76131 Karlsruhe (Germany)

2010-04-06T23:59:59.000Z

33

E-Print Network 3.0 - aperture imaging opportunities Sample Search...  

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

University Collection: Engineering ; Physics 2 PAPER 2004-230 Investigating Fracture Aperture Distributions Summary: . Keller14 imaged the fracture apertures using X-ray...

34

E-Print Network 3.0 - aperture flow imaging Sample Search Results  

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

Institute of Technology Collection: Engineering 3 PAPER 2004-230 Investigating Fracture Aperture Distributions Summary: to correction. ABSTRACT Fracture aperture is usually...

35

Abstract--We have recently completed a large-area, coded-aperture, gamma-ray imager for use in searching for radiation  

E-Print Network [OSTI]

Abstract-- We have recently completed a large-area, coded- aperture, gamma-ray imager for use. The in- strument uses a rank-19, one-dimensional coded aperture to cast shadow patterns onto a 0.57 m2 Na sufficient radiation can reach a large gamma-ray detec- tor from a small source to make detection possible

Horn, Berthold K.P.

36

Effective fracture geometry obtained with large water sand ratio  

E-Print Network [OSTI]

Shale gas formation exhibits some unusual reservoir characteristics: nano-darcy matrix permeability, presence of natural fractures and gas storage on the matrix surface that makes it unique in many ways. It’s difficult to design an optimum fracture...

Kumar, Amrendra

2009-05-15T23:59:59.000Z

37

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

E-Print Network [OSTI]

Growth of geologic fractures into large-strain populations: review of nomenclature, subcritical at the earliest stages of fracture nucleation). Slow, subcritical crack growth in rock is associated

38

MULTI-PHASE FRACTURE-MATRIX INTERACTIONS UNDER STRESS CHANGES  

SciTech Connect (OSTI)

The main objectives of this project are to quantify the changes in fracture porosity and multiphase transport properties as a function of confining stress. These changes will be integrated into conceptual and numerical models that will improve our ability to predict and optimize fluid transport in fractured system. This report details our progress on: (a) developing the direct experimental measurements of fracture aperture and topology and fluid occupancy using high-resolution x-ray micro-tomography, (b) quantifying the effect of confining stress on the distribution of fracture aperture, and (c) characterization of shear fractures and their impact on multi-phase flow. The three-dimensional surface that describes the large-scale structure of the fracture in the porous medium can be determined using x-ray micro-tomography with significant accuracy. Several fractures have been scanned and the fracture aperture maps have been extracted. The success of the mapping of fracture aperture was followed by measuring the occupancy of the fracture by two immiscible phases, water and decane, and water and kerosene. The distribution of fracture aperture depends on the effective confining stress on the nature of the rock and the type and distribution of the asperities that keep the fracture open. Fracture apertures at different confining stresses were obtained by micro-tomography covering a range of about two thousand psig. Initial analysis of the data shows a significant aperture closure with increase in effective confining stress. Visual descriptions of the process are shown in the report while detailed analysis of the behavior of the distribution of fracture aperture is in progress. Both extensional and shear fractures are being considered. The initial multi-phase flow tests were done in extensional fractures. Several rock samples with induced shear fracture are being studies, and some of the new results are presented in this report. These samples are being scanned in order to quantify the distribution of apertures and the nature of the asperities. Low resolution images of fluids in a sample with a shear fracture were performed and they provide the confidence that flow patterns and saturations could be determined in the future. A series of water imbibition tests were conducted in which water was injected into a fracture and its migration into the matrix was monitored with CT and DR x-ray techniques. The objective is to understand the impact of the fracture, its topology and occupancy on the nature of mass transfer between the matrix and the fracture. Counter-current imbibition next to the fracture was observed and quantified, including the influence of formation layering.

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

2005-06-15T23:59:59.000Z

39

Edit paper Methods for Large Scale Hydraulic Fracture Monitoring  

E-Print Network [OSTI]

In this paper we propose computationally efficient and robust methods for estimating the moment tensor and location of micro-seismic event(s) for large search volumes. Our contribution is two-fold. First, we propose a novel joint-complexity measure, namely the sum of nuclear norms which while imposing sparsity on the number of fractures (locations) over a large spatial volume, also captures the rank-1 nature of the induced wavefield pattern. This wavefield pattern is modeled as the outer-product of the source signature with the amplitude pattern across the receivers from a seismic source. A rank-1 factorization of the estimated wavefield pattern at each location can therefore be used to estimate the seismic moment tensor using the knowledge of the array geometry. In contrast to existing work this approach allows us to drop any other assumption on the source signature. Second, we exploit the recently proposed first-order incremental projection algorithms for a fast and efficient implementation of the resulting...

Ely, Gregory

2013-01-01T23:59:59.000Z

40

Developing Magnetorheological Finishing (MRF) Technology for the Manufacture of Large-Aperture Optics in Megajoule Class Laser Systems  

SciTech Connect (OSTI)

Over the last eight years we have been developing advanced MRF tools and techniques to manufacture meter-scale optics for use in Megajoule class laser systems. These systems call for optics having unique characteristics that can complicate their fabrication using conventional polishing methods. First, exposure to the high-power nanosecond and sub-nanosecond pulsed laser environment in the infrared (>27 J/cm{sup 2} at 1053 nm), visible (>18 J/cm{sup 2} at 527 nm), and ultraviolet (>10 J/cm{sup 2} at 351 nm) demands ultra-precise control of optical figure and finish to avoid intensity modulation and scatter that can result in damage to the optics chain or system hardware. Second, the optics must be super-polished and virtually free of surface and subsurface flaws that can limit optic lifetime through laser-induced damage initiation and growth at the flaw sites, particularly at 351 nm. Lastly, ultra-precise optics for beam conditioning are required to control laser beam quality. These optics contain customized surface topographical structures that cannot be made using traditional fabrication processes. In this review, we will present the development and implementation of large-aperture MRF tools and techniques specifically designed to meet the demanding optical performance challenges required in large-aperture high-power laser systems. In particular, we will discuss the advances made by using MRF technology to expose and remove surface and subsurface flaws in optics during final polishing to yield optics with improve laser damage resistance, the novel application of MRF deterministic polishing to imprint complex topographical information and wavefront correction patterns onto optical surfaces, and our efforts to advance the technology to manufacture large-aperture damage resistant optics.

Menapace, J A

2010-10-27T23:59:59.000Z

Note: This page contains sample records for the topic "large aperture fractures" 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

In-situ monitoring of surface post-processing in large aperture fused silica optics with Optical Coherence Tomography  

SciTech Connect (OSTI)

Optical Coherence Tomography is explored as a method to image laser-damage sites located on the surface of large aperture fused silica optics during post-processing via CO{sub 2} laser ablation. The signal analysis for image acquisition was adapted to meet the sensitivity requirements for this application. A long-working distance geometry was employed to allow imaging through the opposite surface of the 5-cm thick optic. The experimental results demonstrate the potential of OCT for remote monitoring of transparent material processing applications.

Guss, G M; Bass, I l; Hackel, R P; Mailhiot, C; Demos, S G

2008-02-08T23:59:59.000Z

42

Estimating the fracture density of small-scale vertical fractures when large-scale vertical fractures are present  

E-Print Network [OSTI]

When fractures are vertical, aligned and their dimensions are small relative to the seismic wavelength, the medium can be considered to be an equivalent Horizontal Transverse Isotropic (HTI) medium. However, geophysical ...

Liu, Yuwei

2013-01-01T23:59:59.000Z

43

OVERBURDEN PRESSURE AFFECTS FRACTURE APERTURE  

E-Print Network [OSTI]

in the Petroleum Recovery Research Center at the New Mexico Institute of Mining and Technology (NMIMT). He holds MS and PhD degrees in petroleum engineering from New Mexico Institute of Mining and Technology. He serves.S. Department of Energy-sponsored pilot project "Investigation of Efficiency Improvements During CO2 Injection

Schechter, David S.

44

CSNI Project for Fracture Analyses of Large-Scale International Reference Experiments (FALSIRE II)  

SciTech Connect (OSTI)

A summary of Phase II of the Project for FALSIRE is presented. FALSIRE was created by the Fracture Assessment Group (FAG) of the OECD/NEA`s Committee on the Safety of Nuclear Installations (CNSI) Principal Working Group No. 3. FALSIRE I in 1988 assessed fracture methods through interpretive analyses of 6 large-scale fracture experiments in reactor pressure vessel (RPV) steels under pressurized- thermal-shock (PTS) loading. In FALSIRE II, experiments examined cleavage fracture in RPV steels for a wide range of materials, crack geometries, and constraint and loading conditions. The cracks were relatively shallow, in the transition temperature region. Included were cracks showing either unstable extension or two stages of extensions under transient thermal and mechanical loads. Crack initiation was also investigated in connection with clad surfaces and with biaxial load. Within FALSIRE II, comparative assessments were performed for 7 reference fracture experiments based on 45 analyses received from 22 organizations representing 12 countries. Temperature distributions in thermal shock loaded samples were approximated with high accuracy and small scatter bands. Structural response was predicted reasonably well; discrepancies could usually be traced to the assumed material models and approximated material properties. Almost all participants elected to use the finite element method.

Bass, B.R.; Pugh, C.E.; Keeney, J. [Oak Ridge National Lab., TN (United States); Schulz, H.; Sievers, J. [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Koeln (Gemany)

1996-11-01T23:59:59.000Z

45

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

E-Print Network [OSTI]

from previous evaluations of fracture hydromechanicalof flow through fractures in rock, In: Proceedings ofsaturated, variable-aperture fracture, Geophys. Res. Lett. ,

Cappa, F.

2009-01-01T23:59:59.000Z

46

Mode I fracture of a biopolymer gel: rate-dependent dissipation and large deformations disentangled  

E-Print Network [OSTI]

We have designed a new experimental setup able to investigate fracture of soft materials at small scales. At high crack velocity, where energy is mostly dissipated through viscoelastic processes, we observe an increasingly large high strain domain in the crack tip vicinity. Taking advantage of our ability to determine where linear elasticity breaks down, we derive a simple prediction for the evolution of the energy release rate with the crack velocity.

Maxime Lefranc; Elisabeth Bouchaud

2015-01-06T23:59:59.000Z

47

Fracture compliance estimation using borehole tube waves  

E-Print Network [OSTI]

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

Bakku, Sudhish Kumar

48

NESC-VII: Fracture Mechanics Analyses of WPS Experiments on Large-scale Cruciform Specimen  

SciTech Connect (OSTI)

This paper describes numerical analyses performed to simulate warm pre-stress (WPS) experiments conducted with large-scale cruciform specimens within the Network for Evaluation of Structural Components (NESC-VII) project. NESC-VII is a European cooperative action in support of WPS application in reactor pressure vessel (RPV) integrity assessment. The project aims in evaluation of the influence of WPS when assessing the structural integrity of RPVs. Advanced fracture mechanics models will be developed and performed to validate experiments concerning the effect of different WPS scenarios on RPV components. The Oak Ridge National Laboratory (ORNL), USA contributes to the Work Package-2 (Analyses of WPS experiments) within the NESCVII network. A series of WPS type experiments on large-scale cruciform specimens have been conducted at CEA Saclay, France, within the framework of NESC VII project. This paper first describes NESC-VII feasibility test analyses conducted at ORNL. Very good agreement was achieved between AREVA NP SAS and ORNL. Further analyses were conducted to evaluate the NESC-VII WPS tests conducted under Load-Cool-Transient- Fracture (LCTF) and Load-Cool-Fracture (LCF) conditions. This objective of this work is to provide a definitive quantification of WPS effects when assessing the structural integrity of reactor pressure vessels. This information will be utilized to further validate, refine, and improve the WPS models that are being used in probabilistic fracture mechanics computer codes now in use by the NRC staff in their effort to develop risk-informed updates to Title 10 of the U.S. Code of Federal Regulations (CFR), Part 50, Appendix G.

Yin, Shengjun [ORNL; Williams, Paul T [ORNL; Bass, Bennett Richard [ORNL

2011-01-01T23:59:59.000Z

49

Multi-Phase Fracture-Matrix Interactions Under Stress Changes  

SciTech Connect (OSTI)

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

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

2005-12-07T23:59:59.000Z

50

MULTI-PHASE FRACTURE-MATRIX INTERACTIONS UNDER STRESS CHANGES  

SciTech Connect (OSTI)

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

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

2002-10-28T23:59:59.000Z

51

Solar Central Receiver with an Irising Aperture  

E-Print Network [OSTI]

. If the aperture is small, it will be inefficient for periods when the solar isolation is inclined due to spillage. However, if the aperture is large, it will be inefficient for periods when the solar isolation is normal, due to excess heat radiation and convection...

Galal, T.; Kulaib, A. M.; Abuzaid, M.

2010-01-01T23:59:59.000Z

52

Experimental and Analytical Study of Multidimensional Imbibition in Fractured Porous Media, SUPRI TR-129  

SciTech Connect (OSTI)

Using an X-ray computerized tomography (CT) scanner, and a novel, CT-compatible core holder, performed a series of experiments to study air and oil expulsion from rock samples by capillary imbibition of water in a three-dimensional geometry. The air-water system was useful in that a relatively large number of experiments can be conducted to delineate physical processes. Different injection rates and fracture apertures were utilized. Two different fracture flow regimes were identified. The ''filling-fracture'' regime shows a plane source that grows in length due to relatively slow water flow through fractures. In the second, ''instantly-filled fracture'' regime, the time to fill the fracture is much less than the imbibition time. Here, imbibition performance scales as the square root of time. In the former regime, the mass of water imbibed scales linearly with time.

Rangel-German, E.R.; Kovscek, A.R.

2002-04-24T23:59:59.000Z

53

Rotating Aperture System  

DOE Patents [OSTI]

A rotating aperture system includes a low-pressure vacuum pumping stage with apertures for passage of a deuterium beam. A stator assembly includes holes for passage of the beam. The rotor assembly includes a shaft connected to a deuterium gas cell or a crossflow venturi that has a single aperture on each side that together align with holes every rotation. The rotating apertures are synchronized with the firing of the deuterium beam such that the beam fires through a clear aperture and passes into the Xe gas beam stop. Portions of the rotor are lapped into the stator to improve the sealing surfaces, to prevent rapid escape of the deuterium gas from the gas cell.

Rusnak, Brian (Livermore, CA); Hall, James M. (Livermore, CA); Shen, Stewart (Danville, CA); Wood, Richard L. (Santa Fe, NM)

2005-01-18T23:59:59.000Z

54

Scale-Dependent Fracture-Matrix Interactions And Their Impact on Radionuclide Transport - Final Report  

SciTech Connect (OSTI)

Matrix diffusion and adsorption within a rock matrix are widely regarded as important mechanisms for retarding the transport of radionuclides and other solutes in fractured rock (e.g., Neretnieks, 1980; Tang et al., 1981; Maloszewski and Zuber, 1985; Novakowski and Lapcevic, 1994; Jardine et al., 1999; Zhou and Xie, 2003; Reimus et al., 2003a,b). When remediation options are being evaluated for old sources of contamination, where a large fraction of contaminants reside within the rock matrix, slow diffusion out of the matrix greatly increases the difficulty and timeframe of remediation. Estimating the rates of solute exchange between fractures and the adjacent rock matrix is a critical factor in quantifying immobilization and/or remobilization of DOE-relevant contaminants within the subsurface. In principle, the most rigorous approach to modeling solute transport with fracture-matrix interaction would be based on local-scale coupled advection-diffusion/dispersion equations for the rock matrix and in discrete fractures that comprise the fracture network (Discrete Fracture Network and Matrix approach, hereinafter referred to as DFNM approach), fully resolving aperture variability in fractures and matrix property heterogeneity. However, such approaches are computationally demanding, and thus, many predictive models rely upon simplified models. These models typically idealize fracture rock masses as a single fracture or system of parallel fractures interacting with slabs of porous matrix or as a mobile-immobile or multi-rate mass transfer system. These idealizations provide tractable approaches for interpreting tracer tests and predicting contaminant mobility, but rely upon a fitted effective matrix diffusivity or mass-transfer coefficients. However, because these fitted parameters are based upon simplified conceptual models, their effectiveness at predicting long-term transport processes remains uncertain. Evidence of scale dependence of effective matrix diffusion coefficients obtained from tracer tests highlights this point and suggests that the underlying mechanisms and relationship between rock and fracture properties are not fully understood in large complex fracture networks. In this project, we developed a high-resolution DFN model of solute transport in fracture networks to explore and quantify the mechanisms that control transport in complex fracture networks and how these may give rise to observed scale-dependent matrix diffusion coefficients. Results demonstrate that small scale heterogeneity in the flow field caused by local aperture variability within individual fractures can lead to long-tailed breakthrough curves indicative of matrix diffusion, even in the absence of interactions with the fracture matrix. Furthermore, the temporal and spatial scale dependence of these processes highlights the inability of short-term tracer tests to estimate transport parameters that will control long-term fate and transport of contaminants in fractured aquifers.

Detwiler, Russell

2014-06-30T23:59:59.000Z

55

Shock wave absorber having apertured plate  

DOE Patents [OSTI]

The shock or energy absorber disclosed herein utilizes an apertured plate maintained under the normal level of liquid flowing in a piping system and disposed between the normal liquid flow path and a cavity pressurized with a compressible gas. The degree of openness (or porosity) of the plate is between 0.01 and 0.60. The energy level of a shock wave travelling down the piping system thus is dissipated by some of the liquid being jetted through the apertured plate toward the cavity. The cavity is large compared to the quantity of liquid jetted through the apertured plate, so there is little change in its volume. The porosity of the apertured plate influences the percentage of energy absorbed.

Shin, Yong W. (Western Springs, IL); Wiedermann, Arne H. (Chicago Heights, IL); Ockert, Carl E. (Vienna, VA)

1985-01-01T23:59:59.000Z

56

Shock wave absorber having apertured plate  

DOE Patents [OSTI]

The shock or energy absorber disclosed herein utilizes an apertured plate maintained under the normal level of liquid flowing in a piping system and disposed between the normal liquid flow path and a cavity pressurized with a compressible gas. The degree of openness (or porosity) of the plate is between 0.01 and 0.60. The energy level of a shock wave travelling down the piping system thus is dissipated by some of the liquid being jetted through the apertured plate toward the cavity. The cavity is large compared to the quantity of liquid jetted through the apertured plate, so there is little change in its volume. The porosity of the apertured plate influences the percentage of energy absorbed.

Shin, Y.W.; Wiedermann, A.H.; Ockert, C.E.

1983-08-26T23:59:59.000Z

57

Variable-aperture screen  

DOE Patents [OSTI]

Apparatus is described for separating material into first and second portions according to size including a plurality of shafts, a plurality of spaced disks radiating outwardly from each of the shafts to define apertures and linkage interconnecting the shafts for moving the shafts toward or away from one another to vary the size of the apertures while the apparatus is performing the separating function. 10 figures.

Savage, G.M.

1991-10-29T23:59:59.000Z

58

Large-Scale Fluid-Structure Interaction Simulation of Viscoplastic and Fracturing  

E-Print Network [OSTI]

of large plastic deformations and rupture of thin alu- minum tubes due to the passage of ethylene-oxygen detonations. 1 Introduction The Center for Simulation of Dynamic Response of Materials at the California In with such a "weakly coupled" method, when the evolving interface geometry and velocities are imposed as boundary

Deiterding, Ralf

59

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

SciTech Connect (OSTI)

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

Ahmad Ghassemi

2009-10-01T23:59:59.000Z

60

Scales Depencence of Fracture Density and Fabric in the Damage Zone of a Large Displacement Continental Transform Fault  

E-Print Network [OSTI]

). . ......... 48 Figure 6. Representative map of transgranular fractures for one petrographic thin section (P1B13-1-2T). (a) Transgranular fractures are shown on top of the plane polarized image (PPL) of the thin section. (b) Cross polarized...

Ayyildiz, Muhammed

2012-08-28T23:59:59.000Z

Note: This page contains sample records for the topic "large aperture fractures" 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

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

SciTech Connect (OSTI)

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

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

2003-04-01T23:59:59.000Z

62

Multi-scale approach to invasion percolation of rock fracture networks  

E-Print Network [OSTI]

A multi-scale scheme for the invasion percolation of rock fracture networks with heterogeneous fracture aperture fields is proposed. Inside fractures, fluid transport is calculated on the finest scale and found to be localized in channels as a consequence of the aperture field. The channel network is characterized and reduced to a vectorized artificial channel network (ACN). Different realizations of ACNs are used to systematically calculate efficient apertures for fluid transport inside differently sized fractures as well as fracture intersection and entry properties. Typical situations in fracture networks are parameterized by fracture inclination, flow path length along the fracture and intersection lengths in the entrance and outlet zones of fractures. Using these scaling relations obtained from the finer scales, we simulate the invasion process of immiscible fluids into saturated discrete fracture networks, which were studied in previous works.

Ali N. Ebrahimi; Falk K. Wittel; Nuno A. M. Araújo; Hans J. Herrmann

2014-08-12T23:59:59.000Z

63

Aperture center energy showcase  

SciTech Connect (OSTI)

Sandia and Forest City have established a Cooperative Research and Development Agreement (CRADA), and the partnership provides a unique opportunity to take technology research and development from demonstration to application in a sustainable community. A project under that CRADA, Aperture Center Energy Showcase, offers a means to develop exhibits and demonstrations that present feedback to community members, Sandia customers, and visitors. The technologies included in the showcase focus on renewable energy and its efficiency, and resilience. These technologies are generally scalable, and provide secure, efficient solutions to energy production, delivery, and usage. In addition to establishing an Energy Showcase, support offices and conference capabilities that facilitate research, collaboration, and demonstration were created. The Aperture Center project focuses on establishing a location that provides outreach, awareness, and demonstration of research findings, emerging technologies, and project developments to Sandia customers, visitors, and Mesa del Sol community members.

Torres, J. J.

2012-03-01T23:59:59.000Z

64

Project Profile: Improved Large Aperture Collector Manufacturing...  

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

feasibility demonstrations focused in three main areas: an aggressive manufacturing optimization of the collector sub-structures for lower input material costs & mechanized...

65

Fracture Blisters  

E-Print Network [OSTI]

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

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

2011-01-01T23:59:59.000Z

66

Dipole aperture and superconductor requirements  

SciTech Connect (OSTI)

The cost of an accelerator is not proportional to the aperture. A change in aperture by a certain percentage results in an overall accelerator cost change by only a fraction of that percentage; the fraction may be between 0.1 and 0.5 and is almost independent of the bending field. This estimate is obtained by analyzing the superconductor requirements as a function of aperture and by making rough estimates of the largest cost items of the accelerator such as magnets and ring tunnel.

Wipf, S.L.

1983-12-11T23:59:59.000Z

67

Sparse aperture endoscope  

DOE Patents [OSTI]

An endoscope which reduces the volume needed by the imaging part thereof, maintains resolution of a wide diameter optical system, while increasing tool access, and allows stereographic or interferometric processing for depth and perspective information/visualization. Because the endoscope decreases the volume consumed by imaging optics such allows a larger fraction of the volume to be used for non-imaging tools, which allows smaller incisions in surgical and diagnostic medical applications thus produces less trauma to the patient or allows access to smaller volumes than is possible with larger instruments. The endoscope utilizes fiber optic light pipes in an outer layer for illumination, a multi-pupil imaging system in an inner annulus, and an access channel for other tools in the center. The endoscope is amenable to implementation as a flexible scope, and thus increases the utility thereof. Because the endoscope uses a multi-aperture pupil, it can also be utilized as an optical array, allowing stereographic and interferometric processing.

Fitch, Joseph P. (Livermore, CA)

1999-07-06T23:59:59.000Z

68

Sparse aperture endoscope  

DOE Patents [OSTI]

An endoscope is disclosed which reduces the volume needed by the imaging part, maintains resolution of a wide diameter optical system, while increasing tool access, and allows stereographic or interferometric processing for depth and perspective information/visualization. Because the endoscope decreases the volume consumed by imaging optics such allows a larger fraction of the volume to be used for non-imaging tools, which allows smaller incisions in surgical and diagnostic medical applications thus produces less trauma to the patient or allows access to smaller volumes than is possible with larger instruments. The endoscope utilizes fiber optic light pipes in an outer layer for illumination, a multi-pupil imaging system in an inner annulus, and an access channel for other tools in the center. The endoscope is amenable to implementation as a flexible scope, and thus increases it's utility. Because the endoscope uses a multi-aperture pupil, it can also be utilized as an optical array, allowing stereographic and interferometric processing. 7 figs.

Fitch, J.P.

1999-07-06T23:59:59.000Z

69

Scale-Dependent Fracture-Matrix Interactions and Their Impact on Radionuclide Transport: Development of efficient particle-tracking methods  

SciTech Connect (OSTI)

Matrix Diffusion and Adsorption within a rock matrix are important mechanisms for retarding transport of radionuclides in fractured rock. Due to computational limitations and difficulties in characterizing complex subsurface systems, diffusive exchange between a fracture network and surrounding rock matrix is often modeled using simplified conceptual representations. There is significant uncertainty in “effective” parameters used in these models, such as the “effective matrix diffusivity”. Often, these parameters are estimated by fitting sparse breakthrough data, and estimated values fall outside meaningful ranges, because simplified interpretive models do not consider complex three-dimensional flow. There is limited understanding of the relationship between the effective parameters and rock mass characteristics including network structure and matrix properties. There is also evidence for an apparent scale-dependence in “effective matrix diffusion” coefficients. These observations raise questions on whether fracture-matrix interaction parameters estimated from small-scale tracer tests can be used for predicting radionuclide fate and transport at the scale of DOE field sites. High-resolution three-dimensional Discrete-Fracture-Network-Matrix (DFNM) models based on well-defined local scale transport equations can help to address some of these questions. Due to tremendous advances in computational technology over the last 10 years, DFNM modeling in relatively large domains is now feasible. The overarching objective of our research is to use DFNM modeling to improve fundamental understanding of how effective parameters in conceptual models are related to fracture network structure and matrix properties. An advanced three-dimensional DFNM model is being developed, which combines upscaled particle-tracking algorithms for fracture-matrix interaction and a parallel fracture-network flow simulator. The particle-tracking algorithms allow complexity in flow fields at different scales, and track transport across fracture-matrix interfaces based on rigorous local approximations to the transport equations. This modeling approach can incorporate aperture variability, multi-scale preferential flow and matrix heterogeneity. We developed efficient particle-tracking methods for handling matrix diffusion and adsorption on fracture walls and demonstrated their efficiency for use within the context of large-scale complex fracture network models with variability in apertures across a network of fractures and within individual fractures.

Rajaram, Harihar [University of Colorado, Boulder; Brutz, Michael [University of Colorado, Boulder; Klein, Dylan R [University of Colorado, Boulder; Mallikamas, Wasin [University of Colorado, Boulder

2014-09-18T23:59:59.000Z

70

Simulation on Discrete Fracture Network Using Flexible Voronoi Gridding  

E-Print Network [OSTI]

........................................... 3 1.2.2 Gridding Techniques ............................................................. 4 1.2.2.1 Globally Orthogonal Grid ...................................... 5 1.2.2.2 Corner Point Grid... ................................................... 5 1.2.3 Locally Orthogonal Grid ....................................................... 6 1.3 Introduction to Discrete Fracture Network Simulation ................... 7 1.4 Introduction to Fracture Aperture Measurement Using X-Ray CT...

Syihab, Zuher

2011-02-22T23:59:59.000Z

71

Experimental study of turbulent unconfined groundwater flow in a single fracture  

E-Print Network [OSTI]

Experimental study of turbulent unconfined groundwater flow in a single fracture Jiazhong Qiana groundwater flow in a single fracture under the conditions of different surface roughness and apertures. We found that the gradient of the Reynolds number versus the average velocity in a single fracture

Zhan, Hongbin

72

Using seismic tomography to characterize fracture systems induced by hydraulic fracturing  

SciTech Connect (OSTI)

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

Fehler, M.; Rutledge, J.

1995-01-01T23:59:59.000Z

73

Relative Permeability of Fractured Rock  

SciTech Connect (OSTI)

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

Mark D. Habana

2002-06-30T23:59:59.000Z

74

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

SciTech Connect (OSTI)

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

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

2013-08-01T23:59:59.000Z

75

Analysis of Fracture in Cores from the Tuff Confining Unit beneath Yucca Flat, Nevada Test Site  

SciTech Connect (OSTI)

The role fractures play in the movement of groundwater through zeolitic tuffs that form the tuff confining unit (TCU) beneath Yucca Flat, Nevada Test Site, is poorly known. This is an important uncertainty, because beneath most of Yucca Flat the TCU lies between the sources of radionuclide contaminants produced by historic underground nuclear testing and the regional carbonate aquifer. To gain a better understanding of the role fractures play in the movement of groundwater and radionuclides through the TCU beneath Yucca Flat, a fracture analysis focusing on hydraulic properties was performed on conventional cores from four vertical exploratory holes in Area 7 of Yucca Flat that fully penetrate the TCU. The results of this study indicate that the TCU is poorly fractured. Fracture density for all fractures is 0.27 fractures per vertical meter of core. For open fractures, or those observed to have some aperture, the density is only 0.06 fractures per vertical meter of core. Open fractures are characterized by apertures ranging from 0.1 to 10 millimeter, and averaging 1.1 millimeter. Aperture typically occurs as small isolated openings along the fracture, accounting for only 10 percent of the fracture volume, the rest being completely healed by secondary minerals. Zeolite is the most common secondary mineral occurring in 48 percent of the fractures observed.

Lance Prothro

2008-03-01T23:59:59.000Z

76

WFPC2 aperture photometry and PSF modelling  

E-Print Network [OSTI]

Since the WFPC-2 undersamples the PSF, aperture photometry can produce results which are competetive with profile fitting in many situations. This article reports and investigation of aperture corrections using both real data and PSF models.

N. R. Tanvir; D. R. T. Robinson; T. von Hippel

1995-03-22T23:59:59.000Z

77

"Taking a break" from bisphosphonates: Is it appropriate? http://ryortho.com/largeJoints.php?news=741_Bisphosphonates-and-Unusual-Femur-Fractures  

E-Print Network [OSTI]

INFORMATION I. Epidemiology1-2 a. 10 million Americans have osteoporosis b. 33.6 million have low bone density of the hip c. 1 out of 2 Caucasian women and 1 out of 5 Caucasian men will experience an osteoporosis-related fracture d. Majority of fractures occur in low bone mass rather than osteoporosis e. More than 4 million

Pillow, Jonathan

78

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

SciTech Connect (OSTI)

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

Chen, Z.; Economides, M.J.

1995-12-31T23:59:59.000Z

79

Analysis of the classical pseudo-3D model for hydraulic fracture with equilibrium height growth across stress barriers  

E-Print Network [OSTI]

Analysis of the classical pseudo-3D model for hydraulic fracture with equilibrium height growth t This paper deals with the so-called ``pseudo three-dimensional'' (P3D) model for a hydraulic fracture of the length, height, and aperture of the hydraulic fracture, in contrast to the numerical formulations adopted

Peirce, Anthony

80

Aperture-Tolerant, Chemical-Based Methods to Reduce Channeling  

SciTech Connect (OSTI)

This final technical progress report describes work performed from October 1, 2004, through May 16, 2007, for the project, 'Aperture-Tolerant, Chemical-Based Methods to Reduce Channeling'. We explored the potential of pore-filling gels for reducing excess water production from both fractured and unfractured production wells. Several gel formulations were identified that met the requirements--i.e., providing water residual resistance factors greater than 2,000 and ultimate oil residual resistance factors (F{sub rro}) of 2 or less. Significant oil throughput was required to achieve low F{sub rro} values, suggesting that gelant penetration into porous rock must be small (a few feet or less) for existing pore-filling gels to provide effective disproportionate permeability reduction. Compared with adsorbed polymers and weak gels, strong pore-filling gels can provide greater reliability and behavior that is insensitive to the initial rock permeability. Guidance is provided on where relative-permeability-modification/disproportionate-permeability-reduction treatments can be successfully applied for use in either oil or gas production wells. When properly designed and executed, these treatments can be successfully applied to a limited range of oilfield excessive-water-production problems. We examined whether gel rheology can explain behavior during extrusion through fractures. The rheology behavior of the gels tested showed a strong parallel to the results obtained from previous gel extrusion experiments. However, for a given aperture (fracture width or plate-plate separation), the pressure gradients measured during the gel extrusion experiments were much higher than anticipated from rheology measurements. Extensive experiments established that wall slip and first normal stress difference were not responsible for the pressure gradient discrepancy. To explain the discrepancy, we noted that the aperture for gel flow (for mobile gel wormholing through concentrated immobile gel within the fracture) was much narrower than the width of the fracture. The potential of various approaches were investigated for improving sweep in parts of the Daqing Oil Field that have been EOR targets. Possibilities included (1) gel treatments that are directed at channeling through fractures, (2) colloidal dispersion gels, (3) reduced polymer degradation, (4) more viscous polymer solutions, and (5) foams and other methods. Fractures were present in a number of Daqing wells (both injectors and producers). Because the fractures were narrow far from the wellbore, severe channeling did not occur. On the contrary, fractures near the wellbore aided reservoir sweep. In the February 2006 issue of the Journal of Petroleum Technology, a 'Distinguished-Author-Series' paper claimed that a process using aqueous colloidal dispersion gels (CDG gels) performed superior to polymer flooding. Unfortunately, this claim is misleading and generally incorrect. Colloidal dispersion gels, in their present state of technological development, should not be advocated as an improvement to, or substitute for, polymer flooding.

Randall S. Seright

2007-09-30T23:59:59.000Z

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


81

Medical imaging with coded apertures  

SciTech Connect (OSTI)

Now algorithms were investigated for image reconstruction in emission tomography which could incorporate complex instrumental effects such as might be obtained with a coded aperture system. The investigation focused on possible uses of the wavelet transform to handle non-stationary instrumental effects and analytic continuation of the Radon transform to handle self-absorption. Neither investigation was completed during the funding period and whether such algorithms will be useful remains an open question.

Keto, E.; Libby, S.

1995-06-16T23:59:59.000Z

82

Hydraulic Fracturing (Vermont)  

Broader source: Energy.gov [DOE]

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

83

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

SciTech Connect (OSTI)

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

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

2008-06-01T23:59:59.000Z

84

Effect of non-linear loading paths on sheet metal fracture : large strain in-plane compression followed by uniaxial tension  

E-Print Network [OSTI]

Advanced high strength steel sheets are rapidly entering the transport industry, as their high strength to weight ratio helps improving fuel and costs efficiency. The early ductile fracture of these materials limits their ...

Marcadet, Stephane (Stephane Jean Marie)

2012-01-01T23:59:59.000Z

85

Efficient Geomechanical Simulations of Large-Scale Naturally Fractured Reservoirs Using the Fast Multipole-Displacement Discontinuity Method (FM-DDM)  

E-Print Network [OSTI]

Geothermal and unconventional reservoirs play an important role in supplying fuel for a growing energy demand in the United States. The development of such reservoirs relies on creating a fracture network to provide flow and transport conduits...

Verde Salas, Alexander José

2014-04-28T23:59:59.000Z

86

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

SciTech Connect (OSTI)

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

Huang, Hai; Plummer, Mitchell; Podgorney, Robert

2013-02-01T23:59:59.000Z

87

E-Print Network 3.0 - aperture radar intensity Sample Search...  

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

radar must have a large power-aperture product. Second, in order to obtain accurate wind velocities... arrays. The early radars could be pointed in only a few, Fig. 1. RHI...

88

Hydraulic fracturing in a naturally fractured reservoir  

SciTech Connect (OSTI)

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

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

1994-12-31T23:59:59.000Z

89

Development of RWHet to Simulate Contaminant Transport in Fractured Porous Media  

SciTech Connect (OSTI)

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

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

2012-07-01T23:59:59.000Z

90

Ion mobility spectrometer with virtual aperture grid  

DOE Patents [OSTI]

An ion mobility spectrometer does not require a physical aperture grid to prevent premature ion detector response. The last electrodes adjacent to the ion collector (typically the last four or five) have an electrode pitch that is less than the width of the ion swarm and each of the adjacent electrodes is connected to a source of free charge, thereby providing a virtual aperture grid at the end of the drift region that shields the ion collector from the mirror current of the approaching ion swarm. The virtual aperture grid is less complex in assembly and function and is less sensitive to vibrations than the physical aperture grid.

Pfeifer, Kent B. (Los Lunas, NM); Rumpf, Arthur N. (Albuquerque, NM)

2010-11-23T23:59:59.000Z

91

Hydraulic fracturing-1  

SciTech Connect (OSTI)

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

Not Available

1990-01-01T23:59:59.000Z

92

theoretical and applied fracture  

E-Print Network [OSTI]

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

Cizelj, Leon

93

Large  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011 CERN 73-11Large area avalanche photodiode

94

Variable aperture collimator for high energy radiation  

DOE Patents [OSTI]

An apparatus is disclosed providing a variable aperture energy beam collimator. A plurality of beam opaque blocks are in sliding interface edge contact to form a variable aperture. The blocks may be offset at the apex angle to provide a non-equilateral aperture. A plurality of collimator block assemblies may be employed for providing a channel defining a collimated beam. Adjacent assemblies are inverted front-to-back with respect to one another for preventing noncollimated energy from emerging from the apparatus. An adjustment mechanism comprises a cable attached to at least one block and a hand wheel mechanism for operating the cable. The blocks are supported by guide rods engaging slide brackets on the blocks. The guide rods are pivotally connected at each end to intermediate actuators supported on rotatable shafts to change the shape of the aperture. A divergent collimated beam may be obtained by adjusting the apertures of adjacent stages to be unequal.

Hill, Ronald A. (Albuquerque, NM)

1984-05-22T23:59:59.000Z

95

Numerical Investigation of Interaction Between Hydraulic Fractures and Natural Fractures  

E-Print Network [OSTI]

Hydraulic fracturing of a naturally-fractured reservoir is a challenge for industry, as fractures can have complex growth patterns when propagating in systems of natural fractures in the reservoir. Fracture propagation near a natural fracture (NF...

Xue, Wenxu

2011-02-22T23:59:59.000Z

96

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

SciTech Connect (OSTI)

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

B.M. Freifeild

2001-10-18T23:59:59.000Z

97

Laboratory testing of cement grouting of fractures in welded tuff  

SciTech Connect (OSTI)

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

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

1991-03-01T23:59:59.000Z

98

Borehole deviation surveys are necessary for hydraulic fracture monitoring Leo Eisner, Schlumberger Cambridge Research, Petr Bulant, Charles University in Prague, Jol H. Le Calvez*,  

E-Print Network [OSTI]

Borehole deviation surveys are necessary for hydraulic fracture monitoring Leo Eisner, Schlumberger Not performing accurate borehole deviation surveys for hydraulic fracture monitoring (HFM) and neglecting fracture parameters. Introduction Recently a large number of hydraulic fracture treatments have been

Cerveny, Vlastislav

99

Iterative synthetic aperture radar imaging algorithms   

E-Print Network [OSTI]

Synthetic aperture radar is an important tool in a wide range of civilian and military imaging applications. This is primarily due to its ability to image in all weather conditions, during both the day and the night, ...

Kelly, Shaun Innes

2014-06-30T23:59:59.000Z

100

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

SciTech Connect (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 "large aperture fractures" 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

Hydraulic fracturing in tight, fissured media  

SciTech Connect (OSTI)

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

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

1991-02-01T23:59:59.000Z

102

Prediction of effects of hydraulic fracturing using reservoir and well flow simulation  

SciTech Connect (OSTI)

This paper presents a method to predict and evaluate effects of hydraulic fracturing jobs by using reservoir and well flow numerical simulation. The concept of the method i5 that steam production rate at the operating well head pressure is predicted with different fracture conditions which would be attained by the hydraulic fracturing jobs. Then, the effects of the hydraulic fracturing is evaluated by comparing the predicted steam production rate and that before the hydraulic fracturing. This course of analysis will suggest how large fracture should be created by the fracturing job to attain large enough increase in steam production at the operating condition and the best scheme of the hydraulic fracturing job.

Mineyuki Hanano; Tayuki Kondo

1992-01-01T23:59:59.000Z

103

Fracture Properties From Seismic Scattering  

E-Print Network [OSTI]

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

Burns, Daniel R.

2007-01-01T23:59:59.000Z

104

Finite Conductivity Fractures in Elliptical Coordinates  

E-Print Network [OSTI]

TO THE DEPARTMENT OF PETROLEUM ENGINEERING AND THE COMMITTEE ON GRADUATE STUDIES OF STANFORD UNIVERSITY IN PARTIAL well performance. Indeed, a large number of wells, which could not otherwise be operated economically, it is important that means be available to evaluate fracture effectiveness. The most widely used tool in fracture

Stanford University

105

Accounting for Remaining Injected Fracturing Fluid  

E-Print Network [OSTI]

The technology of multi-stage fracturing of horizontal wells made the development of shale gas reservoirs become greatly successful during the past decades. A large amount of fracturing fluid, usually from 53,000 bbls to 81,400 bbls, is injected...

Zhang, Yannan

2013-12-06T23:59:59.000Z

106

Seismic characterization of fractures  

E-Print Network [OSTI]

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

JM Carcione

2014-06-07T23:59:59.000Z

107

Operations and Maintenance Manual for Large Aperture Scanner System  

SciTech Connect (OSTI)

Operations and maintenance manual includes detailed instructions for system assembly, use, and maintenance.

Jones, Anthony M.; Hall, Thomas E.

2010-04-08T23:59:59.000Z

108

The design of a large aperture high field dipole  

SciTech Connect (OSTI)

The impetus for this design report originated in the Snowmass 88 meeting where the subject of higher energies within the constraints of the existing Tevatron tunnel enclosure was investigated. It was determined that beam transport to the fixed target experimental areas was possible up to an energy of {approximately}1.5 Tev. Collider operation was feasible at somewhat higher energies (1.8 Tev), primarily limited by the ability to design a single turn beam abort system within the constraints of the straight section length. A new accelerator in the existing tunnel would, of necessity, have a similar though not identical lattice and straight section layout to the present Tevatron. Thus when issues arose in the magnet design requiring input from the accelerator standpoint we have assumed a Tevatron like machine. The possibility of using these high field magnets as elements in the existing Tevatron to create new warm space,' for another Interaction Region for example, also emphasizes compatibility with the present machine. 16 refs., 62 figs., 23 tabs.

Harfoush, F.; Harrison, M.; Kerby, J.; Koepke, K.; Mantsch, P.; Nicol, T.; Riddiford, A.; Theilacker, J.

1989-12-01T23:59:59.000Z

109

New results from the LASS (Large Aperture Superconducting Solenoid) spectrometer  

SciTech Connect (OSTI)

New results are presented from analyses of several mesonic and baryonic states containing one or more strange quarks. The data are taken from a high statistics (4 events/nb) study of K p interactions at 11 GeV/c carried out in the LASS Spectrometer at SLAC. New information is reported on the underlying K* states and also evidence for selective coupling of K eta to the K*'s; on the strangeonium members of the axial vector nonets in the K anti K channel; and on evidence for an * state.

Aston, D.; Awaji, N.; Bienz, T.; Bird, F.; D'Amore, J.; Dunwoodie, W.; Endorf, R.; Fujii, K.; Hayashii, H.; Iwata, S.

1987-06-22T23:59:59.000Z

110

Photovoltaic converter having apertured reflective enclosure  

SciTech Connect (OSTI)

This patent describes a photovoltaic converter. It comprises: a photovoltaic cell having an incident face upon which light is directed to cause photogeneration; an enclosure over the incident face, the wall of the enclosure having a reflective inner surface spaced apart from the incident face to permit light reflected from the incident face to be re-reflected by the inner surface and back to the photovoltaic cell; and an aperture through the wall of the enclosure to permit light to fall directly upon the voltaic cell. The ratio of the area of the aperture to the are of the incident face of the photovoltaic cell is less than about 0.2.

Sinton, R.A.; Swanson, R.M.

1990-10-02T23:59:59.000Z

111

Spatial statistics for predicting flow through a rock fracture  

SciTech Connect (OSTI)

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

Coakley, K.J.

1989-03-01T23:59:59.000Z

112

Identifying Fracture Types and Relative Ages Using Fluid Inclusion Stratigraphy  

SciTech Connect (OSTI)

Enhanced Geothermal Systems (EGS) are designed to recover heat from the subsurface by mechanically creating fractures in subsurface rocks. 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

113

Determination of the linear aperture of the SSC (Superconducting Supercollider) clustered lattice used for the conceptual design report  

SciTech Connect (OSTI)

A study is made of the linear aperture for the clustered lattice used for the SSC Conceptual Design Report. Random multipole errors are included in all magnetic elements including the insertion dipoles and quadrupoles. Based on the concept of smear, the linear aperture is equal to the dynamic aperture in the range -0.1 less than or equal to ..delta..P/P less than or equal to 0.03%. Strong coupling for ..delta..P/P > 0% produces large smears. A variation of the smear parameter that is insensitive to coupling is proposed. A comparison is made with results reported in the SSC Conceptual Design Report.

Dell, G.F.

1986-06-23T23:59:59.000Z

114

Hydraulic fractur ing--also called hy  

E-Print Network [OSTI]

Hydraulic fractur ing--also called hy drofracking or frack ing--is a process where large volumes) is an aquatic invasive spe cies listed on the USDA's federal noxious weeds list (http:// www.aphis.usda.gov/plant_health

Goodman, Robert M.

115

Optimal Maneuvers for Distributed Aperture Imaging Systems  

E-Print Network [OSTI]

to the wave vectors (locations in the so-called u-v plane) that are proportional to the relative positions of the apertures. Imaging to specified resolution demands measurement of the Fourier components with adequate signal-to-noise ratio over the interior...

Fitch, Danielle

2012-10-19T23:59:59.000Z

116

Analysis of transverse apertures in a circular waveguide  

E-Print Network [OSTI]

of a transverse aperture will be extremely useful in the design of coupled cavity resonators and circular cavity backed resonant aperture antennas. B. l. iterature Review Many authors have investigated the effects of apertures in both the transverse... 1989 Major Subject: Electrical Engineering ANALYSIS OF TRANSVERSE APERTURES IN A CIRCULAR WAVEGUIDE A Thesis GARY BRYAN EASTHAM Approved as to style and content by: Kai Chang (Chair of Committee) Brian D. Young (Member) Donal L. Parker...

Eastham, Gary Bryan

1989-01-01T23:59:59.000Z

117

Dual aperture dipole magnet with second harmonic component  

DOE Patents [OSTI]

An improved dual aperture dipole electromagnet includes a second-harmonic frequency magnetic guide field winding which surrounds first harmonic frequency magnetic guide field windings associated with each aperture. The second harmonic winding and the first harmonic windings cooperate to produce resultant magnetic waveforms in the apertures which have extended acceleration and shortened reset portions of electromagnet operation.

Praeg, W.F.

1983-08-31T23:59:59.000Z

118

Vacuum aperture isolator for retroreflection from laser-irradiated target  

DOE Patents [OSTI]

The disclosure is directed to a vacuum aperture isolator for retroreflection of a laser-irradiated target. Within a vacuum chamber are disposed a beam focusing element, a disc having an aperture and a recollimating element. The edge of the focused beam impinges on the edge of the aperture to produce a plasma which refracts any retroreflected light from the laser's target.

Benjamin, Robert F. (Los Alamos, NM); Mitchell, Kenneth B. (Los Alamos, NM)

1980-01-01T23:59:59.000Z

119

Dual aperture dipole magnet with second harmonic component  

DOE Patents [OSTI]

An improved dual aperture dipole electromagnet includes a second-harmonic frequency magnetic guide field winding which surrounds first harmonic frequency magnetic guide field windings associated with each aperture. The second harmonic winding and the first harmonic windings cooperate to produce resultant magnetic waveforms in the apertures which have extended acceleration and shortened reset portions of electromagnet operation.

Praeg, Walter F. (Palos Park, IL)

1985-01-01T23:59:59.000Z

120

Spatially Interpolated Nonlinear Anodization in Synthetic Aperture Radar Imagery  

SciTech Connect (OSTI)

Spatially Interpolated Nonlinear Anodization in Synthetic Aperture Original formulation of spatially variant anodization for complex synthetic aperture radar (SAR) imagery oversampled at twice the Nyquist rate (2.OX). Here we report a spatially interpolating, noninteger-oversampled SVA sidelobe. The pixel's apparent IPR location is assessed by comparing its value to the sum of its value plus weighted comparable for exact interpolation. However, exact interpolation implies an ideal sine interpolator3 and large components may not be necessary. Note that P is the summation of IPR diagonal values. The value of a sine IPR on the diagonals is a sine-squared; values much less than cardinal direction (m, n) values. This implies that cardinal direction interpolation requires higher precision than diagonal interpolation. Consequently, we employed a smaller set. The spatially interpolated SVA used an 8-point/4-point sine interpolator described above. Table 1 shows the Table 1 results show a two-times speed-up using the 1.3x oversampled and spatially interpolated SVA over the Figure 1d. Detected results of 1.3x oversampled sine interpolated spatially variant

Eichel, Paul H.; Jakowatz, Jr., Charles V.; Yocky, David A.

1999-06-29T23:59:59.000Z

Note: This page contains sample records for the topic "large aperture fractures" 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

Performance limits for Synthetic Aperture Radar.  

SciTech Connect (OSTI)

The performance of a Synthetic Aperture Radar (SAR) system depends on a variety of factors, many which are interdependent in some manner. It is often difficult to ''get your arms around'' the problem of ascertaining achievable performance limits, and yet those limits exist and are dictated by physics, no matter how bright the engineer tasked to generate a system design. This report identifies and explores those limits, and how they depend on hardware system parameters and environmental conditions. Ultimately, this leads to a characterization of parameters that offer optimum performance for the overall SAR system. For example, there are definite optimum frequency bands that depend on weather conditions and range, and minimum radar PRF for a fixed real antenna aperture dimension is independent of frequency. While the information herein is not new to the literature, its collection into a single report hopes to offer some value in reducing the ''seek time''.

Doerry, Armin Walter

2006-02-01T23:59:59.000Z

122

Characterizing fractured rock for fluid-flow, geomechanical, and paleostress modeling: Methods and preliminary results from Yucca Mountain, Nevada  

SciTech Connect (OSTI)

Fractures have been characterized for fluid-flow, geomechanical, and paleostress modeling at three localities in the vicinity of drill hole USW G-4 at Yucca Mountain in southwestern Nevada. A method for fracture characterization is introduced that integrates mapping fracture-trace networks and quantifying eight fracture parameters: trace length, orientation, connectivity, aperture, roughness, shear offset, trace-length density, and mineralization. A complex network of fractures was exposed on three 214- to 260-m 2 pavements cleared of debris in the upper lithophysal unit of the Tiva Canyon Member of the Miocene Paint-brush Tuff. The pavements are two-dimensional sections through the three-dimensional network of strata-bound fractures. All fractures with trace lengths greater than 0.2 m were mapped and studied.

Barton, C.C.; Larsen, E.; Page, W.R.; Howard, T.M.

1993-12-31T23:59:59.000Z

123

Synthetic aperture radar processing with tiered subapertures  

SciTech Connect (OSTI)

Synthetic Aperture Radar (SAR) is used to form images that are maps of radar reflectivity of some scene of interest, from range soundings taken over some spatial aperture. Additionally, the range soundings are typically synthesized from a sampled frequency aperture. Efficient processing of the collected data necessitates using efficient digital signal processing techniques such as vector multiplies and fast implementations of the Discrete Fourier Transform. Inherent in image formation algorithms that use these is a trade-off between the size of the scene that can be acceptably imaged, and the resolution with which the image can be made. These limits arise from migration errors and spatially variant phase errors, and different algorithms mitigate these to varying degrees. Two fairly successful algorithms for airborne SARs are Polar Format processing, and Overlapped Subaperture (OSA) processing. This report introduces and summarizes the analysis of generalized Tiered Subaperture (TSA) techniques that are a superset of both Polar Format processing and OSA processing. It is shown how tiers of subapertures in both azimuth and range can effectively mitigate both migration errors and spatially variant phase errors to allow virtually arbitrary scene sizes, even in a dynamic motion environment.

Doerry, A.W. [Sandia National Labs., Albuquerque, NM (United States). Synthetic Aperture Radar Dept.

1994-06-01T23:59:59.000Z

124

CHARACTERIZATION OF IN-SITU STRESS AND PERMEABILITY IN FRACTURED RESERVOIRS  

SciTech Connect (OSTI)

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

Daniel R. Burns; M. Nafi Toksoz

2004-07-19T23:59:59.000Z

125

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

E-Print Network [OSTI]

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

Forbis, Robert E.

2014-01-01T23:59:59.000Z

126

3-D description of fracture surfaces and stress-sensitivity analysis for naturally fractured reservoirs  

SciTech Connect (OSTI)

Three kinds of reservoir cores (limestone, sandstone, and shale with natural fractures) were used to study the effect of morphology of fracture surfaces on stress sensitivity. The cores, obtained from the reservoirs with depths of 2170 to 2300 m, have fractures which are mated on a large scale, but unmated on a fine scale. A specially designed photoelectric scanner with a computer was used to describe the topography of the fracture surfaces. Then, theoretical analysis of the fracture closure was carried out based on the fracture topography generated. The scanning results show that the asperity has almost normal distributions for all three types of samples. For the tested samples, the fracture closure predicted by the elastic-contact theory is different from the laboratory measurements because plastic deformation of the aspirates plays an important role under the testing range of normal stresses. In this work, the traditionally used elastic-contact theory has been modified to better predict the stress sensitivity of reservoir fractures. Analysis shows that the standard deviation of the probability density function of asperity distribution has a great effect on the fracture closure rate.

Zhang, S.Q.; Jioa, D.; Meng, Y.F.; Fan, Y.

1997-08-01T23:59:59.000Z

127

A Thermoelastic Hydraulic Fracture Design Tool for Geothermal Reservoir Development  

SciTech Connect (OSTI)

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

Ahmad Ghassemi

2003-06-30T23:59:59.000Z

128

Flow dynamics and solute transport in unsaturated rock fractures  

SciTech Connect (OSTI)

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

Su, G. W.

1999-10-01T23:59:59.000Z

129

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

SciTech Connect (OSTI)

This report describes the work performed during the second 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 artificial fractured cores (AFCs) and X-ray CT to examine the physical mechanisms of bypassing in HFR and NFR that eventually result in less efficient CO{sub 2} flooding in heterogeneous or fracture-dominated reservoirs. To achieve this objective, in this period we concentrated our effort on modeling the fluid flow in fracture surface, examining the fluid transfer mechanisms and describing the fracture aperture distribution under different overburden pressure using X-ray CT scanner.

David S. Schechter

2003-10-01T23:59:59.000Z

130

Self-potential observations during hydraulic fracturing  

E-Print Network [OSTI]

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

Moore, J R; Glaser, Steven D

2007-01-01T23:59:59.000Z

131

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

132

Hydraulic fracture mechanism in unconsolidated formations.  

E-Print Network [OSTI]

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

Hosseini, Seyed Mehran

2012-01-01T23:59:59.000Z

133

A statistical model for the excitation of cavities through apertures  

E-Print Network [OSTI]

In this paper, a statistical model for the coupling of electromagnetic radiation into enclosures through apertures is presented. The model gives a unified picture bridging deterministic theories of aperture radiation, and statistical models necessary for capturing the properties of irregular shaped enclosures. A Monte Carlo technique based on random matrix theory is used to predict and study the power transmitted through the aperture into the enclosure. Universal behavior of the net power entering the aperture is found. Results are of interest for predicting the coupling of external radiation through openings in irregular enclosures and reverberation chambers.

Gradoni, Gabriele; Anlage, Steven M; Ott, Edward

2015-01-01T23:59:59.000Z

134

Functionalized apertures for the detection of chemical and biological materials  

DOE Patents [OSTI]

Disclosed are nanometer to micron scale functionalized apertures constructed on a substrate made of glass, carbon, semiconductors or polymeric materials that allow for the real time detection of biological materials or chemical moieties. Many apertures can exist on one substrate allowing for the simultaneous detection of numerous chemical and biological molecules. One embodiment features a macrocyclic ring attached to cross-linkers, wherein the macrocyclic ring has a biological or chemical probe extending through the aperture. Another embodiment achieves functionalization by attaching chemical or biological anchors directly to the walls of the apertures via cross-linkers.

Letant, Sonia E. (Livermore, CA); van Buuren, Anthony W. (Livermore, CA); Terminello, Louis J. (Danville, CA); Thelen, Michael P. (Danville, CA); Hope-Weeks, Louisa J. (Brentwood, CA); Hart, Bradley R. (Brentwood, CA)

2010-12-14T23:59:59.000Z

135

Simulation of Hydraulic Fractures and their Interactions with Natural Fractures  

E-Print Network [OSTI]

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

Sesetty, Varahanaresh

2012-10-19T23:59:59.000Z

136

Fracture characterization from attenuation of Stoneley waves across a fracture  

E-Print Network [OSTI]

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

Bakku, Sudhish Kumar

2012-01-01T23:59:59.000Z

137

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

SciTech Connect (OSTI)

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

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

2008-03-16T23:59:59.000Z

138

TEMPORAL VARIATIONS OF FRACTURE DIRECTIONS AND FRACTURE DENSITIES...  

Open Energy Info (EERE)

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

139

Optical aperture synthesis with electronically connected telescopes  

E-Print Network [OSTI]

Highest resolution imaging in astronomy is achieved by interferometry, connecting telescopes over increasingly longer distances, and at successively shorter wavelengths. Here, we present the first diffraction-limited images in visual light, produced by an array of independent optical telescopes, connected electronically only, with no optical links between them. With an array of small telescopes, second-order optical coherence of the sources is measured through intensity interferometry over 180 baselines between pairs of telescopes, and two-dimensional images reconstructed. The technique aims at diffraction-limited optical aperture synthesis over kilometre-long baselines to reach resolutions showing details on stellar surfaces and perhaps even the silhouettes of transiting exoplanets. Intensity interferometry circumvents problems of atmospheric turbulence that constrain ordinary interferometry. Since the electronic signal can be copied, many baselines can be built up between dispersed telescopes, and over long...

Dravins, Dainis; Nuñez, Paul D

2015-01-01T23:59:59.000Z

140

A Rare Isolated Trapezoid Fracture  

E-Print Network [OSTI]

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

Afifi, Negean; Lu, Jenny J

2011-01-01T23:59:59.000Z

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


141

Synthetic Aperture Radar Imaging with Motion Estimation and Liliana Borcea  

E-Print Network [OSTI]

Callaghan George Papanicolaou Abstract We introduce from first principles a synthetic aperture radar (SAR calibrated small apertures, (b) preliminary motion estimation from the data using the Wigner transform-band persistent surveillance SAR is a specific application that is covered by our analysis. Detailed numerical

Papanicolaou, George C.

142

Synthetic aperture design for increased SAR image rate  

DOE Patents [OSTI]

High resolution SAR images of a target scene at near video rates can be produced by using overlapped, but nevertheless, full-size synthetic apertures. The SAR images, which respectively correspond to the apertures, can be analyzed in sequence to permit detection of movement in the target scene.

Bielek, Timothy P. (Albuquerque, NM); Thompson, Douglas G. (Albuqerque, NM); Walker, Bruce C. (Albuquerque, NM)

2009-03-03T23:59:59.000Z

143

Microfabricated high-bandpass foucault aperture for electron microscopy  

DOE Patents [OSTI]

A variant of the Foucault (knife-edge) aperture is disclosed that is designed to provide single-sideband (SSB) contrast at low spatial frequencies but retain conventional double-sideband (DSB) contrast at high spatial frequencies in transmission electron microscopy. The aperture includes a plate with an inner open area, a support extending from the plate at an edge of the open area, a half-circle feature mounted on the support and located at the center of the aperture open area. The radius of the half-circle portion of reciprocal space that is blocked by the aperture can be varied to suit the needs of electron microscopy investigation. The aperture is fabricated from conductive material which is preferably non-oxidizing, such as gold, for example.

Glaeser, Robert; Cambie, Rossana; Jin, Jian

2014-08-26T23:59:59.000Z

144

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

E-Print Network [OSTI]

Low-permeability gas wells often produce less than predicted after a fracture treatment. One of the reasons for this is that fracture lengths calculated after stimulation are often less than designed lengths. While actual fracture lengths may...

Lolon, Elyezer P.

2006-04-12T23:59:59.000Z

145

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

SciTech Connect (OSTI)

The objective of this project is to perform unique laboratory experiments with artificial fractured cores (AFCs) and X-ray CT to examine the physical mechanisms of bypassing in HFR and NFR that eventually result in 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

146

Flow focusing in unsaturated fracture networks: A numerical investigation  

SciTech Connect (OSTI)

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

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

2003-04-17T23:59:59.000Z

147

Experimental observations of deformation caused by mineral dissolution in variable-aperture fractures  

E-Print Network [OSTI]

are further influenced by stresses in the host rock. To quantitatively explore these coupled processes, we-water reactions. For example, subsurface CO2 sequestration in depleted oil and gas reservoirs or deep saline 1 August 2008. [1] Problems such as CO2 sequestration, petroleum production and nuclear waste

Detwiler, Russell

148

Forward osmosis treatment of drilling mud and fracturing wastewater from oil and gas operations  

E-Print Network [OSTI]

Forward osmosis treatment of drilling mud and fracturing wastewater from oil and gas operations fracturing of wells during oil and gas (O&G) exploration consumes large volumes of fresh water and generates fracturing of oil and gas (O&G) wells are becoming of greater concern in the United States and around

149

E-Print Network 3.0 - advanced synthetic aperture Sample Search...  

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

APERTURE MICROSCOPY: PHYSICS-BASED IMAGE RECONSTRUCTION FROM OPTICAL COHERENCE TOMOGRAPHY DATA Summary: INTERFEROMETRIC SYNTHETIC APERTURE MICROSCOPY: PHYSICS-BASED IMAGE...

150

Motion Measurement for Synthetic Aperture Radar.  

SciTech Connect (OSTI)

Synthetic Aperture Radar (SAR) measures radar soundings from a set of locations typically along the flight path of a radar platform vehicle. Optimal focusing requires precise knowledge of the sounding source locations in 3 - D space with respect to the target scene. Even data driven focusing techniques (i.e. autofocus) requires some degree of initial fidelity in the measurements of the motion of the radar. These requirements may be quite stringent especially for fine resolution, long ranges, and low velocities. The principal instrument for measuring motion is typically an Inertial Measurement Unit (IMU), but these instruments have inherent limi ted precision and accuracy. The question is %22How good does an IMU need to be for a SAR across its performance space?%22 This report analytically relates IMU specifications to parametric requirements for SAR. - 4 - Acknowledgements Th e preparation of this report is the result of a n unfunded research and development activity . Although this report is an independent effort, it draws heavily from limited - release documentation generated under a CRADA with General Atomics - Aeronautical System, Inc. (GA - ASI), and under the Joint DoD/DOE Munitions Program Memorandum of Understanding. Sandia National Laboratories is a multi - program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of En ergy's National Nuclear Security Administration under contract DE - AC04 - 94AL85000.

Doerry, Armin W.

2015-01-01T23:59:59.000Z

151

Simulation of naturally fractured reservoirs using empirical transfer function  

E-Print Network [OSTI]

This research utilizes the imbibition experiments and X-ray tomography results for modeling fluid flow in naturally fractured reservoirs. Conventional dual porosity simulation requires large number of runs to quantify transfer function parameters...

Tellapaneni, Prasanna Kumar

2004-09-30T23:59:59.000Z

152

Suspensions in hydraulic fracturing  

SciTech Connect (OSTI)

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

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

1996-12-31T23:59:59.000Z

153

aperture optical system: Topics by E-print Network  

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

20 21 22 23 24 25 Next Page Last Page Topic Index 1 May 15, 2003 Vol. 28, No. 10 OPTICS LETTERS 801 Phase retrieval for high-numerical-aperture optical systems Biotechnology...

154

Receiver for solar energy collector having improved aperture aspect  

DOE Patents [OSTI]

A secondary concentrator for use in receiver systems for linear focusing primary concentrators is provided with reflector wings at each end. The wings increase the capture of light rays reflected from areas adjacent the rim of a primary concentrator, increasing the apparent aperture size of the absorber as viewed from the rim of the primary concentrator. The length, tilt, and curvature of the wing reflectors can be adjusted to provide an absorber having a desired aperture aspect.

McIntire, William R. (Downers Grove, IL)

1984-01-01T23:59:59.000Z

155

FRACTURING FLUID CHARACTERIZATION FACILITY  

SciTech Connect (OSTI)

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

Subhash Shah

2000-08-01T23:59:59.000Z

156

Ultrasound-Confirmed Frontal Bone Fracture  

E-Print Network [OSTI]

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

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

2009-01-01T23:59:59.000Z

157

Fracture, aging and disease in bone  

E-Print Network [OSTI]

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

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

2006-01-01T23:59:59.000Z

158

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

159

E-Print Network 3.0 - aperture optics system Sample Search Results  

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

optics system Search Powered by Explorit Topic List Advanced Search Sample search results for: aperture optics...

160

Investigation of Created Fracture Geometry through Hydraulic Fracture Treatment Analysis  

E-Print Network [OSTI]

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

Ahmed, Ibraheem 1987-

2012-11-30T23:59:59.000Z

Note: This page contains sample records for the topic "large aperture fractures" 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

Hydrogen-Assisted Fracture: Materials Testing and Variables Governing Fracture  

E-Print Network [OSTI]

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

162

Reservoir fracture characterizations from seismic scattered waves  

E-Print Network [OSTI]

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

Fang, Xinding

2012-01-01T23:59:59.000Z

163

Hydraulic transmissivity and heat exchanges: aperture lowpass filtering model 1 Natural open joints in rocks commonly present multi-scale self-affine apertures. This  

E-Print Network [OSTI]

Hydraulic transmissivity and heat exchanges: aperture lowpass filtering model 1 SUMMARY Natural aperture that describes at best the macroscopic properties (hydraulic conductivity, heat exchange of the effective hydraulic and thermal properties (apertures). A detailed study of the influence of the bandwidth

Paris-Sud XI, Université de

164

Modeling Single Well Injection-Withdrawal (SWIW) Tests for Characterization of Complex Fracture-Matrix Systems  

SciTech Connect (OSTI)

The ability to reliably predict flow and transport in fractured porous rock is an essential condition for performance evaluation of geologic (underground) nuclear waste repositories. In this report, a suite of programs (TRIPOLY code) for calculating and analyzing flow and transport in two-dimensional fracture-matrix systems is used to model single-well injection-withdrawal (SWIW) tracer tests. The SWIW test, a tracer test using one well, is proposed as a useful means of collecting data for site characterization, as well as estimating parameters relevant to tracer diffusion and sorption. After some specific code adaptations, we numerically generated a complex fracture-matrix system for computation of steady-state flow and tracer advection and dispersion in the fracture network, along with solute exchange processes between the fractures and the porous matrix. We then conducted simulations for a hypothetical but workable SWIW test design and completed parameter sensitivity studies on three physical parameters of the rock matrix - namely porosity, diffusion coefficient, and retardation coefficient - in order to investigate their impact on the fracture-matrix solute exchange process. Hydraulic fracturing, or hydrofracking, is also modeled in this study, in two different ways: (1) by increasing the hydraulic aperture for flow in existing fractures and (2) by adding a new set of fractures to the field. The results of all these different tests are analyzed by studying the population of matrix blocks, the tracer spatial distribution, and the breakthrough curves (BTCs) obtained, while performing mass-balance checks and being careful to avoid some numerical mistakes that could occur. This study clearly demonstrates the importance of matrix effects in the solute transport process, with the sensitivity studies illustrating the increased importance of the matrix in providing a retardation mechanism for radionuclides as matrix porosity, diffusion coefficient, or retardation coefficient increase. Interestingly, model results before and after hydrofracking are insensitive to adding more fractures, while slightly more sensitive to aperture increase, making SWIW tests a possible means of discriminating between these two potential hydrofracking effects. Finally, we investigate the possibility of inferring relevant information regarding the fracture-matrix system physical parameters from the BTCs obtained during SWIW testing.

Cotte, F.P.; Doughty, C.; Birkholzer, J.

2010-11-01T23:59:59.000Z

165

Seismic Fracture Characterization Methods for Enhanced Geothermal...  

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

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

166

Seismic Fracture Characterization Methods for Enhanced Geothermal...  

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

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

167

Fluid Flow Modeling in Fractures  

E-Print Network [OSTI]

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

Sarkar, Sudipta

2004-01-01T23:59:59.000Z

168

On the fracture toughness of advanced materials  

SciTech Connect (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

169

FRACTURE STIMULATION IN ENHANCED GEOTHERMAL  

E-Print Network [OSTI]

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

Stanford University

170

Simulation of fracture fluid cleanup and its effect on long-term recovery in tight gas reservoirs  

E-Print Network [OSTI]

technologies, such as large volume fracture treatments, are required before a reasonable profit can be made. Hydraulic fracturing is one of the best methods to stimulate a tight gas well. Most fracture treatments result in 3-6 fold increases in the productivity...

Wang, Yilin

2009-05-15T23:59:59.000Z

171

Fracture-resistant lanthanide scintillators  

DOE Patents [OSTI]

Lanthanide halide alloys have recently enabled scintillating gamma ray spectrometers comparable to room temperature semiconductors (<3% FWHM energy resolutions at 662 keV). However brittle fracture of these materials upon cooling hinders the growth of large volume crystals. Efforts to improve the strength through non-lanthanide alloy substitution, while preserving scintillation, have been demonstrated. Isovalent alloys having nominal compositions of comprising Al, Ga, Sc, Y, and In dopants as well as aliovalent alloys comprising Ca, Sr, Zr, Hf, Zn, and Pb dopants were prepared. All of these alloys exhibit bright fluorescence under UV excitation, with varying shifts in the spectral peaks and intensities relative to pure CeBr.sub.3. Further, these alloys scintillate when coupled to a photomultiplier tube (PMT) and exposed to .sup.137Cs gamma rays.

Doty, F. Patrick (Livermore, CA)

2011-01-04T23:59:59.000Z

172

Development of an equivalent homogenous fluid model for pseudo-two-phase (air plus water) flow through fractured rock  

SciTech Connect (OSTI)

Fracture flow of two-phase mixtures is particularly applicable to the coal mining and coal bed methane projects in Australia. A one-dimensional steady-state pseudo-two-phase flow model is proposed for fractured rock. The model considers free flow of a compressible mixture of air and water in an inclined planar fracture and is based upon the conservation of momentum and the 'cubic' law. The flow model is coupled to changes in the stress environment through the fracture normal stiffness, which is related to changes in fracture aperture. The model represents the individual air and water phases as a single equivalent homogenous fluid. Laboratory testing was performed using the two-phase high-pressure triaxial apparatus on 54 mm diameter (approximately 2: 1 height: diameter) borehole cores intersected by induced near-axial fractures. The samples were of Triassic arenaceous fine-medium grained sandstone (known as the Eckersley Formation) that is found locally in the Southern Coalfield of New South Wales. The sample fracture roughness was assessed using a technique based upon Fourier series analysis to objectively attribute a joint roughness coefficient. The proposed two-phase flow model was verified using the recorded laboratory data obtained over a range of triaxial confining pressures (i.e., fracture normal stresses).

Price, J.; Indraratna, B. [University of Wollongong, Wollongong, NSW (Australia). School of Civil Engineering

2005-07-01T23:59:59.000Z

173

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

E-Print Network [OSTI]

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

Nakagawa, S.

2010-01-01T23:59:59.000Z

174

Fracture Characterization in Enhanced Geothermal Systems by Wellbore...  

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

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

175

aperture shield materials: Topics by E-print Network  

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

aperture shield materials First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Light-weight Flexible...

176

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

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

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

177

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

SciTech Connect (OSTI)

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

Mukul M. Sharma

2005-03-01T23:59:59.000Z

178

E-Print Network 3.0 - aperture diffractive space Sample Search...  

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

for: aperture diffractive space Page: << < 1 2 3 4 5 > >> 1 20 May 2011: PHYS 252 Wave Optics (Chapter 22) Summary: -Wesley. Circular-Aperture Diffraction Light of wavelength...

179

E-Print Network 3.0 - aperture lightweight space Sample Search...  

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

binary search spaces. An aperture pattern k... , "Coded aperture imaging in X- and Gamma- ray astronomy," Space Science Reviews, pp. 349-403, 1987. 2 9... What are Good...

180

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 "large aperture fractures" 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

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

SciTech Connect (OSTI)

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

David S. Schechter

2002-10-30T23:59:59.000Z

182

High Energy Gas Fracturing Test  

SciTech Connect (OSTI)

The Rocky Mountain Oilfield Testing Center (RMOTC) has recently completed two tests of a high-energy gas fracturing system being developed by Western Technologies of Crossville, Tennessee. The tests involved the use of two active wells located at the Naval Petroleum Reserve No. 3 (NPR-3), thirty-five miles north of Casper, Wyoming (See Figure 1). During the testing process the delivery and operational system was enhanced by RMOTC, Western Technologies, and commercial wireline subcontractors. RMOTC has assisted an industrial client in developing their technology for high energy gas fracturing to a commercial level. The modifications and improvements implemented during the technology testing process are instrumental in all field testing efforts at RMOTC. The importance of well selection can also be critical in demonstrating the success of the technology. To date, significant increases in well productivity have been clearly proven in well 63-TPX-10. Gross fluid production was initially raised by a factor of three. Final production rates increased by a factor of six with the use of a larger submersible pump. Well productivity (bbls of fluid per foot of drawdown) increased by a factor of 15 to 20. The above results assume that no mechanical damage has occurred to the casing or cast iron bridge plug which could allow well production from the Tensleep ''B'' sand. In the case of well 61-A-3, a six-fold increase in total fluid production was seen. Unfortunately, the increase is clouded by the water injection into the well that was necessary to have a positive fluid head on the propellant tool. No significant increase in oil production was seen. The tools which were retrieved from both 63-TPX-10 and 61-A-3 indicated a large amount of energy, similar to high gram perforating, had been expended downhole upon the formation face.

Schulte, R.

2001-02-27T23:59:59.000Z

183

Identification and quantification of fracture behavior through reservoir simulation  

SciTech Connect (OSTI)

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

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

1995-08-01T23:59:59.000Z

184

Brittle Fracture Ductile to Brittle transition  

E-Print Network [OSTI]

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

Subramaniam, Anandh

185

FRACTURED PETROLEUM RESERVOIRS  

SciTech Connect (OSTI)

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

Abbas Firoozabadi

1999-06-11T23:59:59.000Z

186

Fracture characterization and discrimination criteria for karst and tectonic fractures in the Ellenburger Group, West Texas: Implications for reservoir and exploration models  

SciTech Connect (OSTI)

In the Ellenburger Group fractured dolomite reservoirs of West Texas, it is extremely difficult to distinguish between multiple phases of karst-related fracturing, modifications to the karst system during burial, and overprinting tectonic fractures. From the analyses of drill core, the authors developed criteria to distinguish between karst and tectonic fractures. In addition, they have applied these criteria within the context of a detailed diagenetic cement history that allows them to further refine the fracture genesis and chronology. In these analyses, the authors evaluated the relationships between fracture intensity, morphologic attributes, host lithology, fracture cement, and oil-staining. From this analysis, they have been able to characterize variations in Ellenburger tectonic fracture intensity by separating these fractures from karst-related features. In general, the majority of fracturing in the Ellenburger is caused by karst-related fracturing although a considerable percentage is caused by tectonism. These findings underscore the importance of considering the complete geologic evolution of a karst reservoir during exploration and field development programs. The authors have been able to more precisely define the spatial significance of the fracture data sets by use of oriented core from Andector Field. They have also demonstrated the importance of these results for exploration and reservoir development programs in West Texas, and the potential to extrapolate these results around the globe. Given the historic interest in the large hydrocarbon reserves in West Texas carbonate reservoirs, results of this study will have tremendous implications for exploration and production strategies targeting vuggy, fractured carbonate systems not only in West Texas, but throughout the globe.

Hoak, T.E. [Science Applications International Corp., Germantown, MD (United States); [Kestrel Geoscience, Littleton, CO (United States); Sundberg, K.R. [Phillips Petroleum Co., Bartlesville, OK (United States); Deyhim, P. [Oklahoma State Univ., Stillwater, OK (United States); Ortoleva, P. [Indiana Univ., Bloomington, IN (United States). Lab. for Computational Geodynamics

1998-12-31T23:59:59.000Z

187

Correlating toughness and roughness in ductile fracture  

E-Print Network [OSTI]

Three dimensional calculations of ductile crack growth under mode I plane strain, small scale yielding conditions are carried out using an elastic-viscoplastic constitutive relation for a progres- sively cavitating plastic solid with two populations of void nucleating second phase particles. Full field solutions are obtained for three dimensional material microstructures characterized by ran- dom distributions of void nucleating particles. Crack growth resistance curves and fracture surface roughness statistics are calculated using standard procedures. The range of void nucleating particle volume fractions considered give rise to values of toughness, JIC, that vary by a factor of four. For all volume fractions considered, the computed fracture surfaces are self-affine over a size range of about two orders of magnitude with a roughness exponent of 0.54 $\\pm$ 0.03. For small void nucleating particle volume fractions, the mean large particle spacing serves as a single dominant length scale. In this regime, the c...

Ponson, Laurent; Osovski, Shmulik; Bouchaud, Elisabeth; Tvergaard, Viggo; Needleman, Alan

2013-01-01T23:59:59.000Z

188

Complications in Ankle Fracture Surgery.  

E-Print Network [OSTI]

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

Ovaska, Mikko

2014-01-01T23:59:59.000Z

189

Fracture model for cemented aggregates  

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

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

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

2013-01-01T23:59:59.000Z

190

Seismic anisotropy of fractured rock  

E-Print Network [OSTI]

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

M. Schoenberg, C. M. Sayers

2000-02-18T23:59:59.000Z

191

PNP - a new class of coded aperture arrays  

SciTech Connect (OSTI)

The authors report on a new class of coded aperture arrays which has all the desirable imaging characteristics of the Uniformly Redundant Array (URA), yet is constructible in dimensions which are forbidden to that design. In addition, the new arrays (called PNP arrays, for Pseudo-Noise Product) are of self-supporting geometry, simplifying fabrication and making them ideal candidates for situations where active collimators are employed, as for example in high-energy ..gamma..-ray imaging. A unique and important feature of all PNP arrays is the ability to produce reconstructed images whose noise is uniform regardless of the original source structure. A comparison of the predicted performance of the PNP, URA, GEOMETRIC, and PINHOLE designs is presented. Coded aperture imaging, which utilizes position-sensitive detectors, was first proposed as a means for detecting x-ray and gamma sources.

Gottesman, S.R.; Schneid, E.J.

1986-02-01T23:59:59.000Z

192

Interferometric hydrofracture microseism localization using neighboring fracture  

E-Print Network [OSTI]

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

Poliannikov, Oleg V.

2011-05-19T23:59:59.000Z

193

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.

194

GEOLOGY AND FRACTURE SYSTEM AT STRIPA  

E-Print Network [OSTI]

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

Olkiewicz, O.

2010-01-01T23:59:59.000Z

195

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

SciTech Connect (OSTI)

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

Liu, H.H.; Rutqvist, J.

2009-10-01T23:59:59.000Z

196

Exploring the physicochemical processes that govern hydraulic fracture through laboratory  

E-Print Network [OSTI]

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

Belmonte A; Connelly P

197

Seismic Fracture Characterization Methods for Enhanced Geothermal...  

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

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

198

Fracture Processes Observed with A Cryogenic Detector  

E-Print Network [OSTI]

In the early stages of running of the CRESST dark matter search using sapphire detectors at very low temperature, an unexpectedly high rate of signal pulses appeared. Their origin was finally traced to fracture events in the sapphire due to the very tight clamping of the detectors. During extensive runs the energy and time of each event was recorded, providing large data sets for such phenomena. We believe this is the first time the energy release in fracture has been directly and accurately measured on a microscopic event-by-event basis. The energy threshold corresponds to the breaking of only a few hundred covalent bonds, a sensitivity some orders of magnitude greater than that of previous technique. We report some features of the data, including energy distributions, waiting time distributions, autocorrelations and the Hurst exponent. The energy distribution appear to follow a power law, $dN/dE\\propto E^{-\\beta}$, similar to the power law for earthquake magnitudes, and after appropriate translation, with a similar exponent. In the time domain,the waiting time $w$ or gap distribution between events has a power law behavior at small $w$ and an exponential fall-off at large $w,$ and can be fit $\\propto w^{-\\alpha}e^{-w/w_0}$. The autocorrelation function shows time correlations lasting for substantial parts of an hour. An asymmetry is found around large events, with higher count rates after, as opposed to before,the large event .

J. Astrom; P. C. F. Di Stefano; F. Proebst; L. Stodolsky; J. Timonen; C. Bucci; S. Cooper; C. Cozzini; F. v. Feilitzsch; H. Kraus; J. Marchese; O. Meier; U. Nagel; Y. Ramachers; W. Seidel; M. Sisti; S. Uchaikin; L. Zerle

2006-03-21T23:59:59.000Z

199

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

SciTech Connect (OSTI)

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

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

1997-08-01T23:59:59.000Z

200

Chemical Signatures of and Precursors to Fractures Using Fluid Inclusion Stratigraphy  

SciTech Connect (OSTI)

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

Lorie M. Dilley

2011-03-30T23:59:59.000Z

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


201

Effects of oxygen on fracturing fluids  

SciTech Connect (OSTI)

The stability of polysaccharide gels at high temperature is limited by such factors as pH, mechanical degradation, and oxidants. Oxygen is unavoidably placed in fracturing fluids through dissolution of air. To prevent premature degradation of the fracturing fluid by this oxidant, oxygen scavengers are commonly used. In this paper, the effects of oxygen and various oxygen scavengers on gel stability will be presented. Mechanical removal of oxygen resulted in surprisingly stable fracturing gels at 275 F. However, chemical removal of oxygen gave mixed results. Test data from sodium thiosulfate, sodium sulfite, and sodium erythorbate used as oxygen scavengers/gel stabilizers showed that the efficiency of oxygen removal from gels did not directly coincide with the viscosity retention of the gel, and large excesses of additives were necessary to provide optimum gel stabilization. The inability of some oxygen scavengers to stabilize the gel was the result of products created from the interaction of oxygen with the oxygen scavenger, which in turn, produced species that degraded the gel. The ideal oxygen scavenger should provide superior gel stabilization without creating detrimental side reaction products. Of the materials tested, sodium thiosulfate appeared to be the most beneficial.

Walker, M.L.; Shuchart, C.E.; Yaritz, J.G.; Norman, L.R.

1995-11-01T23:59:59.000Z

202

Fracture and Healing of Rock Salt Related to Salt Caverns  

SciTech Connect (OSTI)

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

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

1999-03-01T23:59:59.000Z

203

Modeling the Fracture of Ice Sheets on Parallel Computers  

SciTech Connect (OSTI)

The objective of this project was to investigate the complex fracture of ice and understand its role within larger ice sheet simulations and global climate change. This objective was achieved by developing novel physics based models for ice, novel numerical tools to enable the modeling of the physics and by collaboration with the ice community experts. At the present time, ice fracture is not explicitly considered within ice sheet models due in part to large computational costs associated with the accurate modeling of this complex phenomena. However, fracture not only plays an extremely important role in regional behavior but also influences ice dynamics over much larger zones in ways that are currently not well understood. To this end, our research findings through this project offers significant advancement to the field and closes a large gap of knowledge in understanding and modeling the fracture of ice sheets in the polar regions. Thus, we believe that our objective has been achieved and our research accomplishments are significant. This is corroborated through a set of published papers, posters and presentations at technical conferences in the field. In particular significant progress has been made in the mechanics of ice, fracture of ice sheets and ice shelves in polar regions and sophisticated numerical methods that enable the solution of the physics in an efficient way.

Waisman, Haim [Columbia University] [Columbia University; Tuminaro, Ray [Sandia National Labs] [Sandia National Labs

2013-10-10T23:59:59.000Z

204

Fracture of synthetic diamond M. D. Droty  

E-Print Network [OSTI]

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

Ritchie, Robert

205

Water Use for Hydraulic Fracturing: A Texas Sized Problem?  

E-Print Network [OSTI]

The state of Texas could face a 2.7 trillion gallon shortfall of water by 2060. Hydraulic fracturing (HF) requires large amounts of water for each well. Tax incentives should be offered to companies that substitute brackish groundwater for fresh...

LeClere, David

206

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

E-Print Network [OSTI]

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

Rollett, Anthony D.

207

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

E-Print Network [OSTI]

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

Ritchie, Robert

208

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

E-Print Network [OSTI]

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

Ritchie, Robert O.

209

Coded aperture imaging with self-supporting uniformly redundant arrays  

DOE Patents [OSTI]

A self-supporting uniformly redundant array pattern for coded aperture imaging. The present invention utilizes holes which are an integer times smaller in each direction than holes in conventional URA patterns. A balance correlation function is generated where holes are represented by 1's, nonholes are represented by -1's, and supporting area is represented by 0's. The self-supporting array can be used for low energy applications where substrates would greatly reduce throughput. The balance correlation response function for the self-supporting array pattern provides an accurate representation of the source of nonfocusable radiation.

Fenimore, Edward E. (Los Alamos, NM)

1983-01-01T23:59:59.000Z

210

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

SciTech Connect (OSTI)

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

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

1994-02-01T23:59:59.000Z

211

Design of thick aperture for fine-resolution neutron penumbral imaging  

SciTech Connect (OSTI)

Compact sources of 14-MeV neutrons have been imaged with a penumbral-coded aperture at a two-point resolution of 80{mu}m. We desire to improve the penumbral-aperture microscope to obtain resolutions as fine as 10{mu}m. In penumbral-coded-aperture imaging, the resolution is ultimately limited by the sharpness of the aperture point-spread function. I present a design for a thick penumbral aperture that provides the desired sharpness over a field of view of 150{mu}m. The point-spread function of these apertures is sufficiently isoplanatic and distortion-free to allow linear reconstruction of complex source distributions. The designs is generally appropriate for similar imaging techniques, such as fine-resolution neutron or gamma-ray pinhole imaging. 5 refs., 5 figs.

Ress, D.

1989-10-19T23:59:59.000Z

212

Risk assessment of groundwater contamination from hydraulic fracturing fluid spills in Pennsylvania  

E-Print Network [OSTI]

Fast-paced growth in natural gas production in the Marcellus Shale has fueled intense debate over the risk of groundwater contamination from hydraulic fracturing and the shale gas extraction process at large. While several ...

Fletcher, Sarah Marie

2012-01-01T23:59:59.000Z

213

To appear in the International Journal of Fracture Cavitation in Rubber: An Elastic Instability or a Fracture Phenomenon?  

E-Print Network [OSTI]

To appear in the International Journal of Fracture Cavitation in Rubber: An Elastic Instability that cavitation in rubber -- that is, the sudden growth of inherent defects in rubber into large enclosed cavities incomplete. Essentially, this is because the local stretches around the defects at which cavitation initiates

Lopez-Pamies, Oscar

214

Sensitivity analysis of fracture scattering  

E-Print Network [OSTI]

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

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

2010-01-01T23:59:59.000Z

215

Optimization of fracture treatment designs  

E-Print Network [OSTI]

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

Rueda, Jose Ignacio

2012-06-07T23:59:59.000Z

216

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

217

Fracture-Induced Anisotropic Attenuation  

E-Print Network [OSTI]

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

2012-03-23T23:59:59.000Z

218

Aperture-based antihydrogen gravity experiment: Parallel plate geometry  

SciTech Connect (OSTI)

An analytical model and a Monte Carlo simulation are presented of an experiment that could be used to determine the direction of the acceleration of antihydrogen due to gravity. The experiment would rely on methods developed by existing antihydrogen research collaborations. The configuration consists of two circular, parallel plates that have an axis of symmetry directed away from the center of the earth. The plates are separated by a small vertical distance, and include one or more pairs of circular barriers that protrude from the upper and lower plates, thereby forming an aperture between the plates. Antihydrogen annihilations that occur just beyond each barrier, within a “shadow” region, are asymmetric on the upper plate relative to the lower plate. The probability for such annihilations is determined for a point, line and spheroidal source of antihydrogen. The production of 100,000 antiatoms is predicted to be necessary for the aperture-based experiment to indicate the direction of free fall acceleration of antimatter, provided that antihydrogen is produced within a sufficiently small antiproton plasma at a temperature of 4 K.

Rocha, J. R.; Hedlof, R. M.; Ordonez, C. A. [Department of Physics, University of North Texas, Denton, Texas 76203 (United States)] [Department of Physics, University of North Texas, Denton, Texas 76203 (United States)

2013-10-15T23:59:59.000Z

219

A comparison of spotlight synthetic aperture radar image formation techniques  

SciTech Connect (OSTI)

Spotlight synthetic aperture radar images can be formed from the complex phase history data using two main techniques: (1) polar-to-cartesian interpolation followed by two-dimensional inverse Fourier transform (2DFFT), and (2) convolution backprojection (CBP). CBP has been widely used to reconstruct medical images in computer aided tomography, and only recently has been applied to form synthetic aperture radar imagery. It is alleged that CBP yields higher quality images because (1) all the Fourier data are used and (2) the polar formatted data is used directly to form a 2D Cartesian image and therefore 2D interpolation is not required. This report compares the quality of images formed by CBP and several modified versions of the 2DFFT method. We show from an image quality point of view that CBP is equivalent to first windowing the phase history data and then interpolating to an exscribed rectangle. From a mathematical perspective, we should expect this conclusion since the same Fourier data are used to form the SAR image. We next address the issue of parallel implementation of each algorithm. We dispute previous claims that CBP is more readily parallelizable than the 2DFFT method. Our conclusions are supported by comparing execution times between massively parallel implementations of both algorithms, showing that both experience similar decreases in computation time, but that CBP takes significantly longer to form an image.

Knittle, C.D.; Doren, N.E.; Jakowatz, C.V.

1996-10-01T23:59:59.000Z

220

A thermal neutron source imager using coded apertures  

SciTech Connect (OSTI)

To facilitate the process of re-entry vehicle on-site inspections, it would be useful to have an imaging technique which would allow the counting of deployed multiple nuclear warheads without significant disassembly of a missile`s structure. Since neutrons cannot easily be shielded without massive amounts of materials, they offer a means of imaging the separate sources inside a sealed vehicle. Thermal neutrons carry no detailed spectral information, so their detection should not be as intrusive as gamma ray imaging. A prototype device for imaging at close range with thermal neutrons has been constructed using an array of {sup 3}He position-sensitive gas proportional counters combined with a uniformly redundant coded aperture array. A sealed {sup 252}Cf source surrounded by a polyethylene moderator is used as a test source. By means of slit and pinhole experiments, count rates of image-forming neutrons (those which cast a shadow of a Cd aperture on the detector) are compared with the count rates for background neutrons. The resulting ratio, which limits the available image contrast, is measured as a function of distance from the source. The envelope of performance of the instrument is defined by the contrast ratio, the angular resolution, and the total count rate as a function of distance from the source. These factors will determine whether such an instrument could be practical as a tool for treaty verification.

Vanier, P.E.; Forman, L.; Selcow, E.C.

1995-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "large aperture fractures" 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

Design and Implementation of Energized Fracture Treatment in Tight Gas Sands  

SciTech Connect (OSTI)

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

Mukul Sharma; Kyle Friehauf

2009-12-31T23:59:59.000Z

222

E-Print Network 3.0 - aperture radar interferometry Sample Search...  

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

path difference between apertures. Expressions are given for the measured Source: Fienup, James R. - Institute of Optics & Department of Electrical and Computer Engineering,...

223

E-Print Network 3.0 - aperture radar processing Sample Search...  

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

imaging). We... improved resolution from microwave synthetic-aperture ... Source: Fienup, James R. - Institute of Optics & Department of Electrical and Computer Engineering,...

224

Apparatus and method for deterministic control of surface figure during full aperture polishing  

DOE Patents [OSTI]

A polishing system configured to polish a lap includes a lap configured to contact a workpiece for polishing the workpiece; and a septum configured to contact the lap. The septum has an aperture formed therein. The radius of the aperture and radius the workpiece are substantially the same. The aperture and the workpiece have centers disposed at substantially the same radial distance from a center of the lap. The aperture is disposed along a first radial direction from the center of the lap, and the workpiece is disposed along a second radial direction from the center of the lap. The first and second radial directions may be opposite directions.

Suratwala, Tayyab Ishaq; Feit, Michael Dennis; Steele, William Augustus

2013-11-19T23:59:59.000Z

225

E-Print Network 3.0 - aperture uvoir space Sample Search Results  

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

Computer Technologies and Information Sciences 52 Quantum Coherence in a Superfluid Josephson Junction Supradeep Narayana and Yuki Sato Summary: of 75 75 60 nm apertures...

226

High Resolution Backside Imaging and Thermography using a Numerical Aperture Increasing Lens  

E-Print Network [OSTI]

High Resolution Backside Imaging and Thermography using a Numerical Aperture Increasing Lens M. S, representing the highest resolution subsurface thermography to date. Keywords: thermal imaging, high

227

E-Print Network 3.0 - aperture restriction localisation Sample...  

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

Collection: Computer Technologies and Information Sciences 2 Abstract: A new design methodology for a stripline-to-microstrip-line coupler using apertures in their common...

228

E-Print Network 3.0 - aluminum oxide aperture Sample Search Results  

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

Search Powered by Explorit Topic List Advanced Search Sample search results for: aluminum oxide aperture Page: << < 1 2 3 4 5 > >> 1 EFFECTS OF INTERFERENCE AND OXIDATION ON...

229

E-Print Network 3.0 - aperture radar insar Sample Search Results  

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

. A further study demonstrated that the phase component of INSAR is only weakly affected by the real aperture... radar (RAR) modulation 12. On the other hand, under ......

230

E-Print Network 3.0 - aperture radar image Sample Search Results  

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

flight trajecto- In synthetic aperture radar (SAR) imaging a scene... -y(s). The projection data and reconstructed ... Source: Yazici, Birsen - Department of Electrical,...

231

E-Print Network 3.0 - aperture tabletop soft Sample Search Results  

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

of IEEE Conference on Computer Vision and Pattern Recognition... Light Fields and Coded Aperture Refocusing, in proceedings of ACM SIGGRAPH 2007 (ACM Transactions... - denheimer,...

232

E-Print Network 3.0 - apertures ii theoretical Sample Search...  

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

IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 39, NO. 2, FEBRUARY 2001 291 Image Reconstruction and Enhanced Resolution Summary: imposed by the aperture function nulls...

233

E-Print Network 3.0 - aperture synthesis observations Sample...  

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

Canarias Collection: Physics 77 Image and Depth from a Conventional Camera with a Coded Aperture Anat Levin Rob Fergus Fredo Durand William T. Freeman Summary: Image and Depth...

234

A 16-m Telescope for the Advanced Technology Large Aperture Telescope (ATLAST) Mission  

E-Print Network [OSTI]

for the telescope and its instruments. Solar array panels, an antenna and a solar sail are also folded up against compartment which is attached to a spacecraft bus which provides power, attitude control and communications and is separated from the launch vehicle, its solar arrays and high gain antenna will be deployed

Sirianni, Marco

235

A study of strange and strangeonium states produced in LASS (Large Aperture Superconducting Solenoid)  

SciTech Connect (OSTI)

Results are presented from the analysis of several final states from a high-sensitivity (4 ev/nb) study of inelastic K/sup -/p interactions at 11 GeV/c carried out in the LASS Spectrometer at SLAC. New information is reported on leading and underlying K* states, and the strangeonium states produced by hypercharge exchange exchange are compared and contrasted with those observed in radiative decays of the J/psi. 8 refs., 15 figs.

Aston, D.; Awaji, N.; Bienz, T.; Bird, F.; D'Amore, J.; Dunwoodie, W.; Endorf, R.; Fujii, K.; Hayashii, H.; Iwata, S.

1986-01-01T23:59:59.000Z

236

Large-Pore Apertures in a Series of Metal-Organic Frameworks | Center for  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert Southwest Region serviceMission Statement TitanProposalsLaboratoryofLandscapingGas

237

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

E-Print Network [OSTI]

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

Ogbechie, Joachim Nwabunwanne

2012-02-14T23:59:59.000Z

238

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

E-Print Network [OSTI]

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

Bakku, Sudhish Kumar

2011-01-01T23:59:59.000Z

239

INTERPRETATION OF A HYDRAULIC FRACTURING EXPERIMENT, MONTICELLO, SOUTH CAROLINA  

E-Print Network [OSTI]

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

Narasimhan, T.N.

2014-01-01T23:59:59.000Z

240

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

Open Energy Info (EERE)

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

Note: This page contains sample records for the topic "large aperture fractures" 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

Fracture Evolution Following a Hydraulic Stimulation within an...  

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

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

242

Aging and Fracture of Human Cortical Bone and Tooth Dentin  

E-Print Network [OSTI]

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

Ager III, Joel W.

2008-01-01T23:59:59.000Z

243

Poroelastic modeling of seismic boundary conditions across a fracture  

E-Print Network [OSTI]

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

Schoenberg, M.A.; Nakagawa, S.

2006-01-01T23:59:59.000Z

244

DNAPL invasion into a partially saturated dead-end fracture  

E-Print Network [OSTI]

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

Su, Grace W.; Javandel, Iraj

2008-01-01T23:59:59.000Z

245

Updated fracture incidence rates for the US version of FRAX®  

E-Print Network [OSTI]

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

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

2010-01-01T23:59:59.000Z

246

Transphyseal Fracture of the Distal Humerus in a Neonate  

E-Print Network [OSTI]

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

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

2011-01-01T23:59:59.000Z

247

Dynamics of DNAPL penetration into fractured porous media  

SciTech Connect (OSTI)

Dense nonaqueous phase liquids (DNAPLs) that pool above stratigraphic contacts as a result of capillary forces can migrate downward through fractures in the underlying fine-grained layer. Although the DNAPL in the fracture is excluded from the surrounding porous matrix by capillary forces, the DNAPL constituent will dissolve and migrate by diffusion into the matrix. As a front of moderately soluble DNAPL advances into a fracture, the flux of dissolved material into the matrix increases until it becomes comparable to the rate of flow into the fracture, reducing the pressure in the DNAPL phase and slowing its advance. If the DNAPL front encounters a constriction with sufficiently large entry pressure, its advance will halt temporarily. But as the concentration gradients driving diffusion into the matrix decrease, there will be less DNAPL lost by diffusion and the DNAPL pressure at the constriction will increase until it exceeds the entry pressure, causing the downward advance of the front to suddenly resume. Because the time scales of diffusion are much slower than those of density flow, this analysis suggests that under certain circumstances a DNAPL can suddenly resume its downward advance after a long period of apparent immobility. In one plausible example, a dichloromethane front passes through 5 m of fractured clay in 16 days, is immobile for more than four years, and then suddenly moves again. Where this phenomenon is possible, removal of DNAPL to protect underlying aquifers becomes more important as a remediation goal.

Ross, B. [Disposal Safety Inc., Washington, DC (United States); Lu, N. [Colorado School of Mines, Golden, CO (United States). Div. of Engineering

1999-01-01T23:59:59.000Z

248

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

SciTech Connect (OSTI)

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

Takashi Kojima; Yasuhiko Nakagawa; Koji Matsuki; Toshiyuki Hashida

1992-01-01T23:59:59.000Z

249

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

E-Print Network [OSTI]

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

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

2000-01-01T23:59:59.000Z

250

Monitoring hydraulic fracture growth: Laboratory experiments  

SciTech Connect (OSTI)

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

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

2000-04-01T23:59:59.000Z

251

Hybrid Compton camera/coded aperture imaging system  

DOE Patents [OSTI]

A system in one embodiment includes an array of radiation detectors; and an array of imagers positioned behind the array of detectors relative to an expected trajectory of incoming radiation. A method in another embodiment includes detecting incoming radiation with an array of radiation detectors; detecting the incoming radiation with an array of imagers positioned behind the array of detectors relative to a trajectory of the incoming radiation; and performing at least one of Compton imaging using at least the imagers and coded aperture imaging using at least the imagers. A method in yet another embodiment includes detecting incoming radiation with an array of imagers positioned behind an array of detectors relative to a trajectory of the incoming radiation; and performing Compton imaging using at least the imagers.

Mihailescu, Lucian (Livermore, CA); Vetter, Kai M. (Alameda, CA)

2012-04-10T23:59:59.000Z

252

Inverse-synthetic-aperture imaging of trees over a ground plane  

SciTech Connect (OSTI)

Recent data collections with the Sandia VHF-UHF synthetic-aperture radar have yielded surprising results; trees appear brighter in the images than expected! In an effort to understand this phenomenon, various small trees have been measured on the Sandia folded compact range with the inverse-synthetic-aperture imaging system. A compilation of these measurements is contained in this report.

Zittel, D.H.; Brock, B.C.; Littlejohn, J.H.; Patitz, W.E.

1995-11-01T23:59:59.000Z

253

Synthetic Aperture Radar Imaging with Motion Estimation and , T. Callaghan1  

E-Print Network [OSTI]

principles a synthetic aperture radar (SAR) imaging and target motion estimation method that is combined of the data into properly calibrated small apertures, (b) motion or platform trajectory perturbation estimation process. X-band persistent surveillance SAR is a specific application that is covered by our

Borcea, Liliana

254

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

E-Print Network [OSTI]

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

Kim, Tae Hyung

2009-05-15T23:59:59.000Z

255

VALIDATION OF MASSIVELY PARALLEL SIMULATIONS OF DYNAMIC FRACTURE AND  

E-Print Network [OSTI]

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

Barr, Al

256

Experimental Evidence for Self-Limiting Reactive Flow through a Fractured Cement Core: Implications for Time-Dependent Wellbore Leakage  

SciTech Connect (OSTI)

We present a set of reactive transport experiments in cement fractures. The experiments simulate coupling between flow and reaction when acidic, CO{sub 2}-rich fluids flow along a leaky wellbore. An analog dilute acid with a pH between 2.0 and 3.15 was injected at constant rate between 0.3 and 9.4 cm/s into a fractured cement core. Pressure differential across the core and effluent pH were measured to track flow path evolution, which was analyzed with electron microscopy after injection. In many experiments reaction was restricted within relatively narrow, tortuous channels along the fracture surface. The observations are consistent with coupling between flow and dissolution/precipitation. Injected acid reacts along the fracture surface to leach calcium from cement phases. Ahead of the reaction front, high pH pore fluid mixes with calcium-rich water and induces mineral precipitation. Increases in the pressure differential for most experiments indicate that precipitation can be sufficient to restrict flow. Experimental data from this study combined with published field evidence for mineral precipitation along cemented annuli suggests that leakage of CO{sub 2}-rich fluids along a wellbore may seal the leakage pathway if the initial aperture is small and residence time allows mobilization and precipitation of minerals along the fracture.

Huerta, Nicolas J.; Hesse, Marc A.; Bryant, Steven L.; Strazisar, Brian R; Lopano, Christina L.

2013-01-01T23:59:59.000Z

257

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

258

2012 Peer Review Overview Agenda  

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

Imaging Fluid Flow in Geothermal Wells Using Distributed Thermal Perturbation Sensing (LBNL) - 512 FY11 AOP 5 Break Break Break Finding Large Aperture Fractures in Geothermal...

259

Characterizing Structural Controls of EGS Candidate and Conventional...  

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

in Nevada through Directed Research and Public Outreach Finding Large Aperture Fractures in Geothermal Resource Areas Using a Three-Component Long-Offset Surface Seismic Survey...

260

Tectonic & Structural Controls of Great Basin Geothermal Systems...  

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

Large Aperture Fractures in Geothermal Resource Areas Using a Three-Component Long-Offset Surface Seismic Survey Detachment Faulting & Geothermal Resources - Pearl Hot Spring, NV...

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


261

GPU-based ultra-fast direct aperture optimization for online adaptive radiation therapy  

E-Print Network [OSTI]

Online adaptive radiation therapy (ART) has great promise to significantly reduce normal tissue toxicity and/or improve tumor control through real-time treatment adaptations based on the current patient anatomy. However, the major technical obstacle for clinical realization of online ART, namely the inability to achieve real-time efficiency in treatment re-planning, has yet to be solved. To overcome this challenge, this paper presents our work on the implementation of an intensity modulated radiation therapy (IMRT) direct aperture optimization (DAO) algorithm on graphics processing unit (GPU) based on our previous work on CPU. We formulate the DAO problem as a large-scale convex programming problem, and use an exact method called column generation approach to deal with its extremely large dimensionality on GPU. Five 9-field prostate and five 5-field head-and-neck IMRT clinical cases with 5\\times5 mm2 beamlet size and 2.5\\times2.5\\times2.5 mm3 voxel size were used to evaluate our algorithm on GPU. It takes onl...

Men, Chunhua; Jiang, Steve B

2010-01-01T23:59:59.000Z

262

1Plastic deformation and fracture processes in metallic and ceramic nanomaterials... 2007 Advanced Study Center Co. Ltd.  

E-Print Network [OSTI]

1Plastic deformation and fracture processes in metallic and ceramic nanomaterials... © 2007-mail: ovidko@def.ipme.ru PLASTIC DEFORMATION AND FRACTURE PROCESSES IN METALLIC AND CERAMIC NANOMATERIALS at the boundaries between the large grains and nanoscale matrix. In the framework of the model, cracks are generated

Ovid'ko Ilya A.

263

Nonplanar fracture propagation from a horizontal wellbore: Experimental study  

SciTech Connect (OSTI)

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

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

1996-08-01T23:59:59.000Z

264

Harmonic experiments to model fracture induced anisotropy KAUST ...  

E-Print Network [OSTI]

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

santos,,,

265

Tracer Methods for Characterizing Fracture Stimulation in Engineered...  

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

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

266

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

E-Print Network [OSTI]

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

267

Modeling of Acid Fracturing in Carbonate Reservoirs  

E-Print Network [OSTI]

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

Al Jawad, Murtada s

2014-06-05T23:59:59.000Z

268

Self-potential observations during hydraulic fracturing  

E-Print Network [OSTI]

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

Moore, Jeffrey R.; Glaser, Steven D.

2008-01-01T23:59:59.000Z

269

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

270

Fluid Flow Simulation in Fractured Reservoirs  

E-Print Network [OSTI]

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

Sarkar, Sudipta

2002-01-01T23:59:59.000Z

271

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

E-Print Network [OSTI]

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

Lu, Zhiming

272

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

E-Print Network [OSTI]

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

Boyer, Edmond

273

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

E-Print Network [OSTI]

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

Grujicic, Mica

274

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

E-Print Network [OSTI]

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

Ritchie, Robert

275

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

E-Print Network [OSTI]

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

Espinosa, Horacio D.

276

Discrete fracture modeling for fractured reservoirs using Voronoi grid blocks  

E-Print Network [OSTI]

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

Gross, Matthew Edward

2007-09-17T23:59:59.000Z

277

Wave Propagation in Fractured Poroelastic Media  

E-Print Network [OSTI]

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

278

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

SciTech Connect (OSTI)

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

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

2006-05-15T23:59:59.000Z

279

Acoustic-emission monitoring during hydraulic fracturing  

SciTech Connect (OSTI)

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

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

1992-06-01T23:59:59.000Z

280

Hydraulic Fracturing in Michigan Integrated Assessment  

E-Print Network [OSTI]

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

Kamat, Vineet R.

Note: This page contains sample records for the topic "large aperture fractures" 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

Regulation of Hydraulic Fracturing in California  

E-Print Network [OSTI]

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

Kammen, Daniel M.

282

Fractured shale reservoirs: Towards a realistic model  

SciTech Connect (OSTI)

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

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

1996-09-01T23:59:59.000Z

283

Challenges in Continuum Modelling of Intergranular Fracture  

E-Print Network [OSTI]

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

Sethna, James P.

284

FRACTURE IN DISORDERED BRITTLE MEDIA A Dissertation  

E-Print Network [OSTI]

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

Sethna, James P.

285

FRACTURE TOUGHNESS OF WOOD AND WOOD COMPOSITES  

E-Print Network [OSTI]

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

Nairn, John A.

286

Models for MetaVCeramic Interface Fracture  

E-Print Network [OSTI]

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

Suo, Zhigang

287

Interferometric hydrofracture microseism localization using neighboring fracture  

E-Print Network [OSTI]

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

Malcolm, Alison

288

Hydraulic Fracture: multiscale processes and moving  

E-Print Network [OSTI]

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

Peirce, Anthony

289

Hydraulic Fracture: multiscale processes and moving  

E-Print Network [OSTI]

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

Peirce, Anthony

290

Introduction That fracture is governed by processes  

E-Print Network [OSTI]

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

Beltz, Glenn E.

291

LA-13194-MS Fracture Characterization of the  

E-Print Network [OSTI]

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

292

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

SciTech Connect (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

293

Capillary fracture of soft gels  

E-Print Network [OSTI]

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

Bostwick, Joshua B

2013-01-01T23:59:59.000Z

294

Relative Permeability of Fractured Rock  

E-Print Network [OSTI]

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

Stanford University

295

Sensitivity and uncertainty analyses applied to one-dimensional radionuclide transport in a layered fractured rock: MULTFRAC --Analytic solutions and local sensitivities; Phase 2, Iterative performance assessment: Volume 1  

SciTech Connect (OSTI)

Exact analytical solutions based on the Laplace transforms are derived for describing the one-dimensional space-time-dependent, advective transport of a decaying species in a layered, saturated rock system intersected by a planar fracture of varying aperture. These solutions, which account for advection in fracture, molecular diffusion into the rock matrix, adsorption in both fracture and matrix, and radioactive decay, predict the concentrations in both fracture and rock matrix and the cumulative mass in the fracture. The solute migration domain in both fracture and rock is assumed to be semi-infinite with non-zero initial conditions. The concentration of each nuclide at the source is allowed to decay either continuously or according to some periodical fluctuations where both are subjected to either a step or band release mode. Two numerical examples related to the transport of Np-237 and Cm-245 in a five-layered system of fractured rock were used to verify these solutions with several well established evaluation methods of Laplace inversion integrals in the real and complex domain. In addition, with respect to the model parameters, a comparison of the analytically derived local sensitivities for the concentration and cumulative mass of Np-237 in the fracture with the ones obtained through a finite-difference method of approximation is also reported.

Gureghian, A.B.; Wu, Y.T.; Sagar, B. [Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses; Codell, R.A. [Nuclear Regulatory Commission, Washington, DC (United States)

1992-12-01T23:59:59.000Z

296

Geomechanical Simulation of Fluid-Driven Fractures  

SciTech Connect (OSTI)

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

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

2012-11-30T23:59:59.000Z

297

CONSTRAINT EFFECT IN FRACTURE WHAT IS IT  

SciTech Connect (OSTI)

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

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

2008-10-29T23:59:59.000Z

298

Lynx: A High-Resolution Synthetic Aperture Radar  

SciTech Connect (OSTI)

Lynx is a high resolution, synthetic aperture radar (SAR) that has been designed and built by Sandia National Laboratories in collaboration with General Atomics (GA). Although Lynx may be operated on a wide variety of manned and unmanned platforms, it is primarily intended to be fielded on unmanned aerial vehicles. In particular, it may be operated on the Predator, I-GNAT, or Prowler II platforms manufactured by GA Aeronautical Systems, Inc. The Lynx production weight is less than 120 lb. and has a slant range of 30 km (in 4 mm/hr rain). It has operator selectable resolution and is capable of 0.1 m resolution in spotlight mode and 0.3 m resolution in stripmap mode. In ground moving target indicator mode, the minimum detectable velocity is 6 knots with a minimum target cross-section of 10 dBsm. In coherent change detection mode, Lynx makes registered, complex image comparisons either of 0.1 m resolution (minimum) spotlight images or of 0.3 m resolution (minimum) strip images. The Lynx user interface features a view manager that allows it to pan and zoom like a video camera. Lynx was developed under corporate finding from GA and will be manufactured by GA for both military and commercial applications. The Lynx system architecture will be presented and some of its unique features will be described. Imagery at the finest resolutions in both spotlight and strip modes have been obtained and will also be presented.

Doerry, A.W.; Hensley, W.H.; Pace, F.; Stence, J.; Tsunoda, S.I.; Walker, B.C.; Woodring, M.

1999-03-08T23:59:59.000Z

299

Synthetic aperture radar and interferometry development at Sandia National Laboratories  

SciTech Connect (OSTI)

Environmental monitoring, earth-resource mapping, and military systems require broad-area imaging at high resolutions. Many times the imagery must be acquired in inclement weather or during night as well as day. Synthetic aperture radar (SAR) provides such a capability. SAR systems take advantage of the long-range propagation characteristics of radar signals and the complex information processing capability of modern digital electronics to provide high resolution imagery. SAR complements photographic and other optical imaging capabilities because of the minimum constrains on time-of-day and atmospheric conditions and because of the unique responses of terrain and cultural targets to radar frequencies. Interferometry is a method for generating a three-dimensional image of terrain. The height projection is obtained by acquiring two SAR images from two slightly differing locations. It is different from the common method of stereoscopic imaging for topography. The latter relies on differing geometric projections for triangulation to define the surface geometry whereas interferometry relies on differences in radar propagation times between the two SAR locations. This paper presents the capabilities of SAR, explains how SAR works, describes a few SAR applications, provides an overview of SAR development at Sandia, and briefly describes the motion compensation subsystem.

NONE

1993-04-01T23:59:59.000Z

300

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

SciTech Connect (OSTI)

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

R. L. Billingsley; V. Kuuskraa

2006-03-31T23:59:59.000Z

Note: This page contains sample records for the topic "large aperture fractures" 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

RESEARCH PROGRAM ON FRACTURED PETROLEUM RESERVOIRS  

SciTech Connect (OSTI)

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

Abbas Firoozabadi

2002-04-12T23:59:59.000Z

302

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

303

Experience proves forced fracture closure works  

SciTech Connect (OSTI)

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

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

1996-01-01T23:59:59.000Z

304

Computational methods for viscoplastic dynamic fracture mechanics analysis  

SciTech Connect (OSTI)

The role of nonlinear rate-dependent effects in the interpretation of crack run-arrest events in ductile materials is being investigated by the Heavy-Section Steel Technology (HSST) program through development and applications of viscoplastic-dynamic finite element analysis techniques. This paper describes a portion of these studies wherein various viscoplastic constitutive models and several proposed nonlinear fracture criteria are being installed in general purpose (ADINA) and special purpose (VISCRK) finite element computer program. The constitutive models implemented in these computer programs include the Bodner-Parton and the Perzyna viscoplastic formulations; the proposed fracture criteria include three parameters that are based on energy principles. The predictive capabilities of the nonlinear techniques are evaluated through applications to a series of HSST wide-plate crack-arrest tests. To assess the impact of including viscoplastic effects in the computational models, values of fracture parameters calculated in elastodynamic and viscoplastic-dynamic analyses are compared for a large wide-plate test. Finally, plans are reviewed for additional computational and experimental studies to assess the utility of viscoplastic analysis techniques in constructing a dynamic inelastic fracture mechanics model for ductile steels. 34 refs., 14 figs.

Bass, B.R.; Pugh, C.E.; Kenney-Walker, J.; Dexter, R.J.; O'Donoghue, P. E.; Schwartz, C. W.

1988-01-01T23:59:59.000Z

305

Tensile Fracture of Welded Polymer Interfaces: Miscibility, Entanglements and Crazing  

E-Print Network [OSTI]

Large-scale molecular simulations are performed to investigate tensile failure of polymer interfaces as a function of welding time $t$. Changes in the tensile stress, mode of failure and interfacial fracture energy $G_I$ are correlated to changes in the interfacial entanglements as determined from Primitive Path Analysis. Bulk polymers fail through craze formation, followed by craze breakdown through chain scission. At small $t$ welded interfaces are not strong enough to support craze formation and fail at small strains through chain pullout at the interface. Once chains have formed an average of about one entanglement across the interface, a stable craze is formed throughout the sample. The failure stress of the craze rises with welding time and the mode of craze breakdown changes from chain pullout to chain scission as the interface approaches bulk strength. The interfacial fracture energy $G_I$ is calculated by coupling the simulation results to a continuum fracture mechanics model. As in experiment, $G_I$ increases as $t^{1/2}$ before saturating at the average bulk fracture energy $G_b$. As in previous simulations of shear strength, saturation coincides with the recovery of the bulk entanglement density. Before saturation, $G_I$ is proportional to the areal density of interfacial entanglements. Immiscibiltiy limits interdiffusion and thus suppresses entanglements at the interface. Even small degrees of immisciblity reduce interfacial entanglements enough that failure occurs by chain pullout and $G_I \\ll G_b$.

Ting Ge; Gary S. Grest; Mark O. Robbins

2014-10-07T23:59:59.000Z

306

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

SciTech Connect (OSTI)

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

Nakagawa, S.; Myer, L.R.

2009-06-15T23:59:59.000Z

307

Acid Fracture and Fracture Conductivity Study of Field Rock Samples  

E-Print Network [OSTI]

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

Underwood, Jarrod

2013-11-15T23:59:59.000Z

308

SNM neutron detection using a time-gated synthetic aperture hybrid approach  

SciTech Connect (OSTI)

This work focuses on using forward and adjoint transport in a hybrid application of 3-D deterministic (PENTRAN) and Monte Carlo (MCNP5) codes to model a series of neutron detector blocks. These blocks, or 'channels, ' contain a unique set of moderators with 4 atm He-3 detectors tuned to detect and profile a gross energy spectrum of a passing neutron (SNM) source. Ganging the units together as a large area system enables one to apply time gating the source-detector response to maximize signal to noise responses from a passing source with minimal background; multiple units may be positioned as a collective synthetic aperture detector array to be used as a way of performing real time neutron spectroscopy for detecting special nuclear materials in moving vehicles. The initial design, detector response coupling, confirmation of initial design functionality using adjoint transport calculations, and realistic simulation using PENTRAN and MCNP5 are presented. Future work will include optimization and application to realistic scenarios and additional sources. (authors)

Molinar, M.; Yi, C.; Edgar, C. A.; Manalo, K.; Chin, M.; Sjoden, G. [Nuclear and Radiological Engineering Program, George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 770 State Street, Atlanta GA 30332-0745 (United States)

2013-07-01T23:59:59.000Z

309

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

310

E-Print Network 3.0 - aperture based imrt Sample Search Results  

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

the values of EUD were calculated. (3) Simulation of IMRT... is the direct aperture optimization (DAO) method. The IMRT plans generated by DAO can be delivered within 10 min......

311

E-Print Network 3.0 - array aperture probes Sample Search Results  

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

29 NEAR-FIELD SCANNING OPTICAL MICRO PROBE INTEGRATED WITH ANANOMETER-SIZED LIGHT EMITTING DIODE Summary: apertures2,3 and probes with a light absorbing gold particle or a...

312

E-Print Network 3.0 - aperture radar 3d Sample Search Results  

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

3d Search Powered by Explorit Topic List Advanced Search Sample search results for: aperture radar 3d Page: << < 1 2 3 4 5 > >> 1 CHAPTER 9CHAPTER 9CHAPTER 9:CHAPTER 9: Active and...

313

E-Print Network 3.0 - apertures Sample Search Results  

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

Sato Summary: in which we take an array of nanoscale apertures that form a superfluid 4He Josephson junction and apply... quantum phase gradients directly along the array. We...

314

E-Print Network 3.0 - aperture grb observatory Sample Search...  

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

Collection: Mathematics 8 arXiv:astro-ph9711245v120Nov1997 To be published in "Gamma-Ray Bursts, 4th Huntsville Symposium", 1998, ed. Summary: aperture to the APT, but has a...

315

Focused synthetic aperture radar processing of ice-sounder data collected over the Greenland ice sheet  

E-Print Network [OSTI]

We developed a synthetic aperture radar (SAR) processing algorithm for airborne/spaceborne ice-sounding radar systems and applied it to data collected in Greenland. By using focused SAR (phase-corrected coherent averaging), we improved along...

Legarsky, J.; Gogineni, Sivaprasad; Akins, T. L.

2001-10-01T23:59:59.000Z

316

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

E-Print Network [OSTI]

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

Pieve La Rosa, Andres Eduardo

2011-08-08T23:59:59.000Z

317

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

318

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

SciTech Connect (OSTI)

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

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

1996-12-31T23:59:59.000Z

319

Multipinhole collimator with 20 apertures for a brain SPECT application  

SciTech Connect (OSTI)

Purpose: Several new technologies for single photon emission computed tomography (SPECT) instrumentation with parallel-hole collimation have been proposed to improve detector sensitivity and signal collection efficiency. Benefits from improved signal efficiency include shorter acquisition times and lower dose requirements. In this paper, the authors show a possibility of over an order of magnitude enhancement in photon detection efficiency (from 7.6 × 10{sup ?5} to 1.6 × 10{sup ?3}) for dopamine transporter (DaT) imaging of the striatum over the conventional SPECT parallel-hole collimators by use of custom-designed 20 multipinhole (20-MPH) collimators with apertures of 0.75 cm diameter. Methods: Quantifying specific binding ratio (SBR) of {sup 123}I-ioflupane or {sup 123}I-iometopane’s signal at the striatal region is a common brain imaging method to confirm the diagnosis of the Parkinson’s disease. The authors performed imaging of a striatal phantom filled with aqueous solution of I-123 and compared camera recovery ratios of SBR acquired between low-energy high-resolution (LEHR) parallel-hole collimators and 20-MPH collimators. Results: With only two-thirds of total acquisition time (20 min against 30 min), a comparable camera recovery ratio of SBR was achieved using 20-MPH collimators in comparison to that from the LEHR collimator study. Conclusions: Their systematic analyses showed that the 20-MPH collimator could be a promising alternative for the DaT SPECT imaging for brain over the traditional LEHR collimator, which could give both shorter scan time and improved diagnostic accuracy.

Lee, Tzu-Cheng; Ellin, Justin R.; Shrestha, Uttam; Seo, Youngho, E-mail: youngho.seo@ucsf.edu [Physics Research Laboratory, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California 94107 (United States); Huang, Qiu [School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030 (China); Gullberg, Grant T. [Department of Radiotracer Development and Imaging Technology, Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94702 (United States)

2014-11-01T23:59:59.000Z

320

Absolute Calibration of a Large-diameter Light Source  

E-Print Network [OSTI]

A method of absolute calibration for large aperture optical systems is presented, using the example of the Pierre Auger Observatory fluorescence detectors. A 2.5 m diameter light source illuminated by an ultra--violet light emitting diode is calibrated with an overall uncertainty of 2.1 % at a wavelength of 365 nm.

Brack, J T; Dorofeev, A; Gookin, B; Harton, J L; Petrov, Y; Rovero, A C

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "large aperture fractures" 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 the Ductile Brittle Fracture Transition in Reactor Pressure Vessel Steels using a Cohesive Zone Model based approach  

SciTech Connect (OSTI)

Fracture properties of Reactor Pressure Vessel (RPV) steels show large variations with changes in temperature and irradiation levels. Brittle behavior is observed at lower temperatures and/or higher irradiation levels whereas ductile mode of failure is predominant at higher temperatures and/or lower irradiation levels. In addition to such temperature and radiation dependent fracture behavior, significant scatter in fracture toughness has also been observed. As a consequence of such variability in fracture behavior, accurate estimates of fracture properties of RPV steels are of utmost importance for safe and reliable operation of reactor pressure vessels. A cohesive zone based approach is being pursued in the present study where an attempt is made to obtain a unified law capturing both stable crack growth (ductile fracture) and unstable failure (cleavage fracture). The parameters of the constitutive model are dependent on both temperature and failure probability. The effect of irradiation has not been considered in the present study. The use of such a cohesive zone based approach would allow the modeling of explicit crack growth at both stable and unstable regimes of fracture. Also it would provide the possibility to incorporate more physical lower length scale models to predict DBT. Such a multi-scale approach would significantly improve the predictive capabilities of the model, which is still largely empirical.

Pritam Chakraborty; S. Bulent Biner

2013-10-01T23:59:59.000Z

322

Thermal single-well injection-withdrawal tracer tests for determining fracture-matrix heat transfer area  

SciTech Connect (OSTI)

Single-well injection-withdrawal (SWIW) tracer tests involve injection of traced fluid and subsequent tracer recovery from the same well, usually with some quiescent time between the injection and withdrawal periods. SWIW are insensitive to variations in advective processes that arise from formation heterogeneities, because upon withdrawal, fluid parcels tend to retrace the paths taken during injection. However, SWIW are sensitive to diffusive processes, such as diffusive exchange of conservative or reactive solutes between fractures and rock matrix. This paper focuses on SWIW tests in which temperature itself is used as a tracer. Numerical simulations demonstrate the sensitivity of temperature returns to fracture-matrix interaction. We consider thermal SWIW response to the two primary reservoir improvements targeted with stimulation, (1) making additional fractures accessible to injected fluids, and (2) increasing the aperture and permeability of pre-existing fractures. It is found that temperature returns in SWIW tests are insensitive to (2), while providing a strong signal of more rapid temperature recovery during the withdrawal phase for (1).

Pruess, K.; Doughty, C.

2010-01-15T23:59:59.000Z

323

Fractured gas reservoirs in the Devonian shale of the Illinois and Appalachian basins  

SciTech Connect (OSTI)

The Devonian and Lower Mississippian black shale sequence of Kentucky includes the New Albany Shale of Illinois basin and the Ohio Shale of the Appalachian basin. Fractured reservoirs in the Ohio Shale contain a major gas resource, but have not been so prolific in the New Albany Shale. The authors propose two models of fractured shale reservoirs in both the Illinois and the Appalachian basins, to be tested with gas production data. (1) Where reactivated basement faults have propagated to the surface, the lack of an effective seal has prevented the development of overpressure. The resulting fracture system is entirely tectonic is origin, and served mainly as a conduit for gas migration from the basin to the surface. Gas accumulations in such reservoirs typically are small and underpressured. (2) Where basement faults have been reactivated but have not reached the surface, a seal on the fractured reservoir is preserved. In areas where thermal maturity has been adequate, overpressuring due to gas generation resulted in a major extension of the fracture system, as well as enhanced gas compression and adsorption. Such gas accumulations are relatively large. Original overpressuring has been largely lost, due both to natural depletion and to uncontrolled production. The relative thermal immaturity of the Illinois basin accounts for the scarcity of the second type of fractured reservoir and the small magnitude of the New Albany Shale gas resource.

Hamilton-Smith, T.; Walker, D.; Nuttall, B. (Kentucky Geological Survey, Lexington (United States))

1991-08-01T23:59:59.000Z

324

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

SciTech Connect (OSTI)

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

Freisatz, W.B.

1988-07-01T23:59:59.000Z

325

Fracture induced anisotropy in viscoelastic UNLP, 11 Octubre de 2012  

E-Print Network [OSTI]

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

Santos, Juan

326

Thermal Fracturing of Geothermal Wells and the Effects of Borehole Orientation  

E-Print Network [OSTI]

An enhanced geothermal system (EGS) expands the potential of geothermal energy by enabling the exploitation of regions that lack conventional hydrothermal resources. The EGS subsurface system is created by engineering enhanced flow paths between injection and production wells. Hydraulic stimulation of existing fracture networks has been successfully achieved for unconventional geothermal resources. More recently proposed concepts increase the use of drilled wellbores in hard rock to connect the injection and production wells. The present work investigates the long-term thermal effects of deviated geothermal wellbores and studies how the cooling of the borehole wall results in thermally induced tensile fractures. The results show that induced fractures are created by a combination of in situ and thermal stresses, and that the extent to which thermally induced tensile wall fractures are created largely depends on how the wellbores are oriented with respect to the pre-existing stresses of the reservoir. If the s...

Hals, Kjetil M D

2012-01-01T23:59:59.000Z

327

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

328

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

329

Wave Propagation in Fractured Poroelastic Media  

E-Print Network [OSTI]

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

2014-06-22T23:59:59.000Z

330

Fracture permeability and seismic wave scattering ŒPoroelastic ...  

E-Print Network [OSTI]

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

Seiji Nakagawa

2010-02-03T23:59:59.000Z

331

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

332

Fracture characteristics and their relationships to producing...  

Open Energy Info (EERE)

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

333

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

Office of Scientific and Technical Information (OSTI)

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

334

Structural Settings Of Hydrothermal Outflow- Fracture Permeability...  

Open Energy Info (EERE)

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

335

Seismic Fracture Characterization Methods for Enhanced Geothermal...  

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

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

336

Microseismic Tracer Particles for Hydraulic Fracturing  

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

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

337

Regional Analysis And Characterization Of Fractured Aquifers...  

Open Energy Info (EERE)

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

338

Microearthquake Technology for EGS Fracture Characterization...  

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

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

339

Naturally fractured tight gas reservoir detection optimization  

SciTech Connect (OSTI)

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

NONE

1998-09-30T23:59:59.000Z

340

Direct aperture optimization for online adaptive radiation therapy  

SciTech Connect (OSTI)

This paper is the first investigation of using direct aperture optimization (DAO) for online adaptive radiation therapy (ART). A geometrical model representing the anatomy of a typical prostate case was created. To simulate interfractional deformations, four different anatomical deformations were created by systematically deforming the original anatomy by various amounts (0.25, 0.50, 0.75, and 1.00 cm). We describe a series of techniques where the original treatment plan was adapted in order to correct for the deterioration of dose distribution quality caused by the anatomical deformations. We found that the average time needed to adapt the original plan to arrive at a clinically acceptable plan is roughly half of the time needed for a complete plan regeneration, for all four anatomical deformations. Furthermore, through modification of the DAO algorithm the optimization search space was reduced and the plan adaptation was significantly accelerated. For the first anatomical deformation (0.25 cm), the plan adaptation was six times more efficient than the complete plan regeneration. For the 0.50 and 0.75 cm deformations, the optimization efficiency was increased by a factor of roughly 3 compared to the complete plan regeneration. However, for the anatomical deformation of 1.00 cm, the reduction of the optimization search space during plan adaptation did not result in any efficiency improvement over the original (nonmodified) plan adaptation. The anatomical deformation of 1.00 cm demonstrates the limit of this approach. We propose an innovative approach to online ART in which the plan adaptation and radiation delivery are merged together and performed concurrently--adaptive radiation delivery (ARD). A fundamental advantage of ARD is the fact that radiation delivery can start almost immediately after image acquisition and evaluation. Most of the original plan adaptation is done during the radiation delivery, so the time spent adapting the original plan does not increase the overall time the patient has to spend on the treatment couch. As a consequence, the effective time allotted for plan adaptation is drastically reduced. For the 0.25, 0.5, and 0.75 cm anatomical deformations, the treatment time was increased by only 2, 4, and 6 s, respectively, as compared to no plan adaptation. For the anatomical deformation of 1.0 cm the time increase was substantially larger. The anatomical deformation of 1.0 cm represents an extreme case, which is rarely observed for the prostate, and again demonstrates the limit of this approach. ARD shows great potential for an online adaptive method with minimal extension of treatment time.

Mestrovic, Ante; Milette, Marie-Pierre; Nichol, Alan; Clark, Brenda G.; Otto, Karl [Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada and Medical Physics, BC Cancer Agency-Vancouver Centre, Vancouver, British Columbia (Canada); Physics and Astronomy, University of British Columbia, Vancouver, British Columbia (Canada) and Medical Physics, BC Cancer Agency-Centre for the Southern Interior, Kelowna, British Columbia (Canada); Department of Radiation Oncology, BC Cancer Agency-Vancouver Centre, Vancouver, British Columbia (Canada); Medical Physics, Ottawa Hospital Regional Cancer Centre, Ottawa, Ontario (Canada); Medical Physics, BC Cancer Agency-Vancouver Centre, Vancouver, British Columbia (Canada)

2007-05-15T23:59:59.000Z

Note: This page contains sample records for the topic "large aperture fractures" 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

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

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

342

Characterization of EGS Fracture Network Lifecycles  

SciTech Connect (OSTI)

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

Gillian R. Foulger

2008-03-31T23:59:59.000Z

343

Laboratory-scale fracture conductivity created by acid etching  

E-Print Network [OSTI]

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

Pournik, Maysam

2009-05-15T23:59:59.000Z

344

FINITE FRACTURE MECHANICS OF MATRIX MICROCRACKING IN COMPOSITES  

E-Print Network [OSTI]

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

Nairn, John A.

345

Seismic characterization of fractured reservoirs using 3D double beams  

E-Print Network [OSTI]

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

Zheng, Yingcai

2012-01-01T23:59:59.000Z

346

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

347

Numerical simulation of hydraulic fracturing  

E-Print Network [OSTI]

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

Warner, Joseph Barnes

1987-01-01T23:59:59.000Z

348

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

E-Print Network [OSTI]

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

Tao, Qingfeng

2010-07-14T23:59:59.000Z

349

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

E-Print Network [OSTI]

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

Wang, Wenxin

2006-04-12T23:59:59.000Z

350

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

351

Modeling Single Well Injection-Withdrawal (SWIW) Tests for Characterization of Complex Fracture-Matrix Systems  

E-Print Network [OSTI]

exchange process. Hydraulic fracturing, or hydrofracking, ismore detail below. Hydraulic fracturing, or hydrofracking,

Cotte, F.P.

2012-01-01T23:59:59.000Z

352

E-Print Network 3.0 - apophyseal ring fracture Sample Search...  

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

fracture Search Powered by Explorit Topic List Advanced Search Sample search results for: apophyseal ring fracture...

353

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

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

define the subsurface system of fractures and mapping of fluid flow. * limited fracture detection capability * lack of high-temperature monitoring tools and sensors *...

354

The Role of Geochemistry and Stress on Fracture Development and...  

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

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

355

Detecting Fractures Using Technology at High Temperatures and...  

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

Fractures Using Technology at High Temperatures and Depths - Geothermal Ultrasonic Fracture Imager (GUFI); 2010 Geothermal Technology Program Peer Review Report Detecting...

356

Tracer Methods for Characterizing Fracture Creation in Enhanced...  

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

Tracer Methods for Characterizing Fracture Creation in Enhanced Geothermal Systems; 2010 Geothermal Technology Program Peer Review Report Tracer Methods for Characterizing Fracture...

357

Fracture Characterization in Enhanced Geothermal Systems by Wellbore...  

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

Fracture Characterization in Enhanced Geothermal Systems by Wellbore and Reservoir Analysis Fracture Characterization in Enhanced Geothermal Systems by Wellbore and Reservoir...

358

Fracture Network and Fluid Flow Imaging for EGS Applications...  

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

Fracture Network and Fluid Flow Imaging for EGS Applications from Multi-Dimensional Electrical Resistivity Structure Fracture Network and Fluid Flow Imaging for EGS Applications...

359

Detecting Fractures Using Technology at High Temperatures and...  

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

Fractures Using Technology at High Temperatures and Depths - Geothermal Ultrasonic Fracture Imager (GUFI) Presentation Number: 015 Investigator: Patterson, Doug (Baker Hughes...

360

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

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

Imaging, Characterizing, and Modeling of Fracture Networks and Fluid Flow in EGS Reservoirs Imaging, Characterizing, and Modeling of Fracture Networks and Fluid Flow in EGS...

Note: This page contains sample records for the topic "large aperture fractures" 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

Irradiation Effects on Human Cortical Bone Fracture Behavior  

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

362

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

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

Imaging, Characterizing, and Modeling of Fracture Networks and Fluid Flow in EGS Reservoirs Lianjie Huang Los Alamos National Lab Seismicity and Reservoir Fracture Characterization...

363

Fracture Evolution Following a Hydraulic Stimulation within an...  

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

define the subsurface system of fractures and mapping of fluid flow. * limited fracture detection capability * lack of high-temperature monitoring tools and sensors *...

364

Fracture Characterization in Enhanced Geothermal Systems by Wellbore...  

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

Fracture Characterization in Enhanced Geothermal Systems by Wellbore and Reservoir Analysis; 2010 Geothermal Technology Program Peer Review Report Fracture Characterization in...

365

Three-dimensional Modeling of Fracture Clusters in Geothermal...  

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

Three-dimensional Modeling of Fracture Clusters in Geothermal Reservoirs; 2010 Geothermal Technology Program Peer Review Report Three-dimensional Modeling of Fracture Clusters in...

366

Joint inversion of electrical and seismic data for Fracture char...  

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

Joint inversion of electrical and seismic data for Fracture char. and Imaging of Fluid Flow in Geothermal Systems Joint inversion of electrical and seismic data for Fracture char....

367

Fracture Evolution Following a Hydraulic Stimulation within an...  

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

Fracture Evolution Following a Hydraulic Stimulation within an EGS Reservoir Fracture Evolution Following a Hydraulic Stimulation within an EGS Reservoir DOE Geothermal Peer Review...

368

Poroelastic modeling of seismic boundary conditions across a fracture  

E-Print Network [OSTI]

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

2007-07-20T23:59:59.000Z

369

A synergistic approach to optimizing hydraulic fracturing  

SciTech Connect (OSTI)

Combining measurement, simulation, and imaging technologies into an integrated program can help operators achieve the best hydraulic fracture treatment possible. Hydrocarbon production can be significantly increased when fractures are extended to the planned length, and fracturing fluid is retained within the zone of interest. Fractures that break out of zone increase the risk of excess water production with the hydrocarbon. Consequently, the ability to select suitable operational parameters for hydraulic fracturing is critical to job success. An evaluation of formation properties and potential barriers to hydraulic fracturing can be made with three-dimensional (3D) simulation to integrate data taken from wireline logs, waveform sonic logs, and microfrac measurements. In-situ stress orientation is determined by use of a downhole extensometer, oriented cores, anelastic strain recovery (ASR) measurements, and borehole imaging logs. Sidewall cores can be taken perpendicular to wellbore walls without distorting the borehole or the core taken; orientation of the cores can be determined with imaging logs run after coring. Natural fractures can be viewed with a downhole video camera lowered into the well on fiberoptic cable. Effectiveness of fracture treatments may be evaluated with various gamma ray logging techniques production logs comparing expected production to actual zonal contribution. Refined procedures that result from after-frac analysis can be used to plain field development for optimal reservoir drainage.

Kessler, C.; Venditto, J.; McMechan, D.; Edwards, P.

1994-12-31T23:59:59.000Z

370

Fracture Conductivity of the Eagle Ford Shale  

E-Print Network [OSTI]

such as the Eagle Ford Shale. This work investigates the fracture conductivities of seven Eagle Ford Shale samples collected from an outcrop of facies B. Rough fractures were induced in the samples and laboratory experiments that closely followed the API RP-61...

Guzek, James J

2014-07-25T23:59:59.000Z

371

Fracture mechanics of cellular glass  

SciTech Connect (OSTI)

Cellular glasses are prime candidate materials for the structural substrate of mirrored glass for solar concentrator reflecting panels. These materials are brittle, however, and susceptible to mechanical failure from slow crack growth caused by a stress corrosion mechanism. The results are detailed of one part of a program established to develop improved cellular glasses and to characterize the behavior of these and commercially available materials. Commercial and developmental cellular glasses were tested and analyzed using standard testing techniques and models developed from linear fracture mechanics. Two models describing the fracture behavior of these materials are developed. Slow crack growth behavior in cellular glass was found to be more complex than that encountered in dense glasses or ceramics. The crack velocity was found to be strongly dependent upon water vapor transport to the tip of the moving crack. The existence of a static fatigue limit was not conclusively established, however, it is speculated that slow crack growth behavior in Region I may be slower, by orders of magnitude, than that found in dense glasses.

Zwissler, J.G.; Adams, M.A.

1981-02-01T23:59:59.000Z

372

Using microstructure observations to quantify fracture properties and improve reservoir simulations. Final report, September 1998  

SciTech Connect (OSTI)

The research for this project provides new technology to understand and successfully characterize, predict, and simulate reservoir-scale fractures. Such fractures have worldwide importance because of their influence on successful extraction of resources. The scope of this project includes creation and testing of new methods to measure, interpret, and simulate reservoir fractures that overcome the challenge of inadequate sampling. The key to these methods is the use of microstructures as guides to the attributes of the large fractures that control reservoir behavior. One accomplishment of the project research is a demonstration that these microstructures can be reliably and inexpensively sampled. Specific goals of this project were to: create and test new methods of measuring attributes of reservoir-scale fractures, particularly as fluid conduits, and test the methods on samples from reservoirs; extrapolate structural attributes to the reservoir scale through rigorous mathematical techniques and help build accurate and useful 3-D models of the interwell region; and design new ways to incorporate geological and geophysical information into reservoir simulation and verify the accuracy by comparison with production data. New analytical methods developed in the project are leading to a more realistic characterization of fractured reservoir rocks. Testing diagnostic and predictive approaches was an integral part of the research, and several tests were successfully completed.

Laubach, S.E.; Marrett, R.; Rossen, W.; Olson, J.; Lake, L.; Ortega, O.; Gu, Y.; Reed, R.

1999-01-01T23:59:59.000Z

373

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

SciTech Connect (OSTI)

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

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

2008-03-12T23:59:59.000Z

374

Operating the LCLS Gas Attenuator and Gas Detector System with Apertures of 6mm Diameter  

SciTech Connect (OSTI)

The possibility of increasing the apertures of the LCLS gas attenuator/gas detector system is considered. It is shown that increase of the apertures from 3 to 6 mm, together with 4-fold reduction of the operation pressure does not adversely affect the vacuum conditions upstream or downstream. No change of the pump speed and the lengths of the differential pumping cells is required. One minor modification is the use of 1.5 cm long tubular apertures in the end cells of the differential pumping system. Reduction of the pressure does not affect performance of the gas attenuator/gas detector system at the FEL energies below, roughly, 2 keV. Some minor performance degradation occurs at higher energies.

Ryutov, D.D.; Bionta, R.M.; Hau-Riege, S.P.; Kishiyama, K.I.; Roeben, M.D.; Shen, S.; /LLNL, Livermore; Stefan, P.M.; /SLAC; ,

2010-11-17T23:59:59.000Z

375

Self-potential observations during hydraulic fracturing  

SciTech Connect (OSTI)

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

Moore, Jeffrey R.; Glaser, Steven D.

2007-09-13T23:59:59.000Z

376

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

SciTech Connect (OSTI)

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

377

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

SciTech Connect (OSTI)

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

Unknown

1999-12-01T23:59:59.000Z

378

Testing sand used in hydraulic fracturing operations  

SciTech Connect (OSTI)

Recommended practices for testing sand used in hydraulic fracturing operations are outlined as developed by the Task Group on Evaluation of Hydraulic Fracturing Sand under the API Subcommittee on Evaluation of Well Completion Materials. The tests recommended were developed to improve the quality of frac sand delivered to the well site, and are for use in evaluating certain physical properties of sand used in hydraulic fracturing operations. The tests suggested enable users to compare physical characteristics of various sands and to select materials most useful for such applications. Parameters to be tested include turbidity, clay and soft particle content, crush resistance, and mineralogic analysis.

Not Available

1983-03-01T23:59:59.000Z

379

Envelope of Fracture Density Dragana Todorovic-Marinic*  

E-Print Network [OSTI]

Envelope of Fracture Density Dragana Todorovic-Marinic* Veritas DGC Ltd., Calgary, Alberta, Canada that interpretation of fractures can be improved by using the envelope of the fracture density. It has been shown that open, fluid (or gas) filled fractures can be identified through the use of the AVAZ method (Gray et. al

Santos, Juan

380

Use of Tracers to Characterize Fractures in Engineered Geothermal Systems  

Broader source: Energy.gov [DOE]

Project Objectives: Measure interwell fracture surface area and fracture spacing using sorbing tracers; measure fracture surface areas adjacent to a single geothermal well using tracers and injection/backflow techniques; design, fabricate and test a downhole instrument for measuring fracture flow following a hydraulic stimulation experiment.

Note: This page contains sample records for the topic "large aperture fractures" 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

Coupling schemes for modeling hydraulic fracture propagation using the XFEM  

E-Print Network [OSTI]

Coupling schemes for modeling hydraulic fracture propagation using the XFEM Elizaveta Gordeliy of hydraulic fractures in an elastic medium. With appropriate enrichment, the XFEM resolves the Neumann(h) accuracy. For hydraulic fracture problems with a lag separating the uid front from the fracture front, we

Peirce, Anthony

382

Calibration of hydraulic and tracer tests in fractured media  

E-Print Network [OSTI]

Calibration of hydraulic and tracer tests in fractured media represented by a DFN Model L. D. Donado, X. Sanchez-Vila, E. Ruiz* & F. J. Elorza** * Enviros Spain S.L. ** UPM #12;Fractured Media Water flows through fractures (matrix basically impervious ­ though relevant to transport) Fractures at all

Politècnica de Catalunya, Universitat

383

Structure and fracture resistance of alligator gar (Atractosteus spatula) armored fish scales  

E-Print Network [OSTI]

Structure and fracture resistance of alligator gar (Atractosteus spatula) armored fish scales Wen is a large fish with flexible armor consisting of ganoid scales. These scales contain a thin layer of ganoine Fish scales are lightweight flexible dermal armor. They charac- teristically overlap; besides

Meyers, Marc A.

384

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

E-Print Network [OSTI]

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...

Correa Castro, Juan

2011-08-08T23:59:59.000Z

385

Basics of Polar-Format algorithm for processing Synthetic Aperture Radar images.  

SciTech Connect (OSTI)

The purpose of this report is to provide a background to Synthetic Aperture Radar (SAR) image formation using the Polar Format (PFA) processing algorithm. This is meant to be an aid to those tasked to implement real-time image formation using the Polar Format processing algorithm.

Doerry, Armin Walter

2012-05-01T23:59:59.000Z

386

High Resolution Backside Imaging and Thermography using a Numerical Aperture Increasing Lens  

E-Print Network [OSTI]

High Resolution Backside Imaging and Thermography using a Numerical Aperture Increasing Lens Shawn inspection alone, it is necessary to develop techniques, such as thermography, with the capability ­solid immersion lens microscopy and thermography. Standard non-contact optical resolution is limited

387

Shallow intraplate earthquakes in Western Australia observed by Interferometric Synthetic Aperture Radar  

E-Print Network [OSTI]

Shallow intraplate earthquakes in Western Australia observed by Interferometric Synthetic Aperture earthquakes in a stable continental region of southwest Western Australia. Both small-magnitude events occur with tectonic processes in this area of Western Australia often initiate in the upper 1 km of crust. Citation

Tregoning, Paul

388

Change Detection Using Synthetic Aperture Sonar: Preliminary Results from the Larvik Trial  

E-Print Network [OSTI]

detection technology for autonomous underwater vehicles (AUVs) equipped with synthetic aperture sonars (SAS of route survey with unmanned systems, this means repeatedly surveying ports and important transit routes the processing have been proposed, however the field as applied to the underwater environment remains in its

Paris-Sud XI, Université de

389

Influence of topographic stress on rock fracture : a two-dimensional numerical model for arbitrary surface topography and comparisons with borehole observations  

E-Print Network [OSTI]

Theoretical calculations indicate that topographic stresses in some landscapes may be large enough to fracture rocks, which in turn could influence slope stability, erosion rates, and bedrock hydrologic properties. These ...

Slim, Mirna I

2013-01-01T23:59:59.000Z

390

Influence of fracture scale heterogeneity on the flow properties of three-dimensional discrete fracture networks (DFN)  

E-Print Network [OSTI]

Influence of fracture scale heterogeneity on the flow properties of three-dimensional discrete fracture networks (DFN) J.-R. de Dreuzy,1,2 Y. Méheust,2 and G. Pichot3 Received 18 May 2012; revised 28 of fractured media has been so far studied independently at the fracture- and network- scales, we propose

Paris-Sud XI, Université de

391

Using the fracture energies for the two films a first estimate of fracture toughness, K, can be found.  

E-Print Network [OSTI]

· Using the fracture energies for the two films a first estimate of fracture toughness, K, can be found. · Assumptions are made to estimate the crack area based on the fracture mode seen in the SEM. · The total crack length is assumed to be 3 times the contact radius, , at the fracture depth. · To find

Collins, Gary S.

392

A Fracture-Mechanics-Based Approach to Fracture Control in Biomedical Devices Manufactured From Superelastic Nitinol Tube  

E-Print Network [OSTI]

A Fracture-Mechanics-Based Approach to Fracture Control in Biomedical Devices Manufactured From: 10.1002/jbm.b.30840 Abstract: Several key fracture-mechanics parameters associated with the onset of subcritical and critical cracking, specifically the fracture toughness, crack-resistance curve, and fatigue

Ritchie, Robert

393

Percutaneous Vertebroplasty for Osteoporotic Compression Fracture: Multivariate Study of Predictors of New Vertebral Body Fracture  

SciTech Connect (OSTI)

Purpose. To investigate the risk factors and relative risk of new compression fractures following vertebroplasty. Methods. Initially, we enrolled 104 consecutive patients with vertebral compression fractures caused by osteoporosis. A total of 83 of the 104 patients visited our hospital for follow-up examinations for more than 4 weeks after vertebroplasty. Logistic regression analysis of the data obtained from these 83 patients was used to determine relative risks of recurrent compression fractures, using 13 different factors. Results. We identified 59 new fractures in 30 of the 83 patients: 41 new fractures in vertebrae adjacent to treated vertebrae; and 18 new fractures in vertebrae not adjacent to treated vertebrae. New fractures occurred in vertebrae adjacent to treated vertebrae significantly more frequently than in vertebrae not adjacent to treated vertebrae. Only cement leakage into the disk was a significant predictor of new vertebral body fracture after vertebroplasty (odds ratio = 4.633). None of the following covariates were associated with increased risk of new fracture: age, gender, bone mineral density, the number of vertebroplasty procedures, the number of vertebrae treated per procedure, the cumulative number of vertebrae treated, the presence of a single untreated vertebra between treated vertebrae, the presence of multiple untreated vertebrae between treated vertebrae, the amount of bone cement injected per procedure, the cumulative amount of bone cement injected, cement leakage into the soft tissue around the vertebra, and cement leakage into the vein.

Komemushi, Atsushi, E-mail: kome64@yo.rim.or.jp; Tanigawa, Noboru; Kariya, Shuji; Kojima, Hiroyuki; Shomura, Yuzo [Kansai Medical University, Department of Radiology (Japan); Komemushi, Sadao [Kinki University, Schoool of Agriculture (Japan); Sawada, Satoshi [Kansai Medical University, Department of Radiology (Japan)

2006-08-15T23:59:59.000Z

394

Hydraulic fracturing accelerates coalbed methane recovery  

SciTech Connect (OSTI)

Methane production from deep coal seams that never will be mined requires hydraulic fracturing for faster, optimal recovery. Since this can be a complex process, proper formation evaluation beforehand is essential, according to this paper.

Holditch, S.A. (Texas A and M Univ. (US)); Ely, J.W.; Semmelbeck, M.E.; Carter, R.H. (S.A. Holditch and Associates (US)); Hinkel, J.J.; Jeffrey, R.G. Jr. (Dowell Schlumberger (US))

1990-11-01T23:59:59.000Z

395

Multiphase flow in fractured porous media  

SciTech Connect (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

396

Dynamic Fracture Toughness of Polymer Composites  

E-Print Network [OSTI]

that of defense or transport. In this project, the focus is on determining dynamic fracture toughness property of fiber reinforced polymer composites by using a combined numerical- experimental methodology. Impact tests are conducted on Split-Hopkinson pressure...

Harmeet Kaur

2012-02-14T23:59:59.000Z

397

Anomalous transport through porous and fractured media  

E-Print Network [OSTI]

Anomalous transport, understood as the nonlinear scaling with time of the mean square displacement of transported particles, is observed in many physical processes, including contaminant transport through porous and fractured ...

Kang, Peter Kyungchul

2014-01-01T23:59:59.000Z

398

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

399

Universal asymptotic umbrella for hydraulic fracture modeling  

E-Print Network [OSTI]

The paper presents universal asymptotic solution needed for efficient modeling of hydraulic fractures. We show that when neglecting the lag, there is universal asymptotic equation for the near-front opening. It appears that apart from the mechanical properties of fluid and rock, the asymptotic opening depends merely on the local speed of fracture propagation. This implies that, on one hand, the global problem is ill-posed, when trying to solve it as a boundary value problem under a fixed position of the front. On the other hand, when properly used, the universal asymptotics drastically facilitates solving hydraulic fracture problems (both analytically and numerically). We derive simple universal asymptotics and comment on their employment for efficient numerical simulation of hydraulic fractures, in particular, by well-established Level Set and Fast Marching Methods.

Linkov, Aleksandr M

2014-01-01T23:59:59.000Z

400

Advanced hydraulic fracturing methods to create in situ reactive barriers  

SciTech Connect (OSTI)

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

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

1997-12-31T23:59:59.000Z

Note: This page contains sample records for the topic "large aperture fractures" 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

Gas condensate damage in hydraulically fractured wells  

E-Print Network [OSTI]

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

Adeyeye, Adedeji Ayoola

2004-09-30T23:59:59.000Z

402

Fracture of Thermosetting Polymers: Experiments and Modeling  

E-Print Network [OSTI]

for the designation as UNDERGRADUATE RESEARCH SCHOLAR A Senior Scholars Thesis by BRAD EVIN BURGESS FRACTURE OF THERMOSETTING POLYMERS: EXPERIMENTS AND MODELING Approved by: Research Advisor: Amine Benzerga Associate Dean for Undergraduate... Scholars Thesis by BRAD EVIN BURGESS iii ABSTRACT Fracture of Thermosetting Polymers: Experiments and Modeling. (April 2009) Brad Evin Burgess Department of Aerospace Engineering Texas A&M University Research Advisor: Dr. Amine Benzerga...

Benzerga, Amine; Burgess, Brad

2011-08-04T23:59:59.000Z

403

FRACTURE TOUGHNESS VARIABILITY IN F82H  

SciTech Connect (OSTI)

The fracture toughness database for F82H displays some anomalous behavior. Metallographic examination reveals banding in the center of 25 mm thick F82H plate, which is more evident in transverse section. The banding is shown to arise because some grains are etched on a very fine scale whereas the remainder is etched more strongly and better delineates the martensite lath structure. However, the banding found does not provide explanation for the anomalous fracture toughness behavior.

Gelles, David S.; Sokolov, M.

2003-09-03T23:59:59.000Z

404

TRITIUM EFFECTS ON WELDMENT FRACTURE TOUGHNESS  

SciTech Connect (OSTI)

The effects of tritium on the fracture toughness properties of Type 304L stainless steel and its weldments were measured. Fracture toughness data are needed for assessing tritium reservoir structural integrity. This report provides data from J-Integral fracture toughness tests on unexposed and tritium-exposed weldments. The effect of tritium on weldment toughness has not been measured until now. The data include tests on tritium-exposed weldments after aging for up to three years to measure the effect of increasing decay helium concentration on toughness. The results indicate that Type 304L stainless steel weldments have high fracture toughness and are resistant to tritium aging effects on toughness. For unexposed alloys, weldment fracture toughness was higher than base metal toughness. Tritium-exposed-and-aged base metals and weldments had lower toughness values than unexposed ones but still retained good toughness properties. In both base metals and weldments there was an initial reduction in fracture toughness after tritium exposure but little change in fracture toughness values with increasing helium content in the range tested. Fracture modes occurred by the dimpled rupture process in unexposed and tritium-exposed steels and welds. This corroborates further the resistance of Type 304L steel to tritium embrittlement. This report fulfills the requirements for the FY06 Level 3 milestone, TSR15.3 ''Issue summary report for tritium reservoir material aging studies'' for the Enhanced Surveillance Campaign (ESC). The milestone was in support of ESC L2-1866 Milestone-''Complete an annual Enhanced Surveillance stockpile aging assessment report to support the annual assessment process''.

Morgan, M; Michael Tosten, M; Scott West, S

2006-07-17T23:59:59.000Z

405

Production-systems analysis for fractured wells  

SciTech Connect (OSTI)

Production-systems analysis has been in use for many years to design completion configurations on the basis of an expected reservoir capacity. The most common equations used for the reservoir calculations are for steady-state radial flow. Most hydraulically fractured wells require the use of an unsteady-state production simulator to predict the higher flow rates associated with the stimulated well. These high flow rates may present problems with excessive pressure drops through production tubing designed for radial-flow production. Therefore, the unsteady-state nature of fractured-well production precludes the use of steady-state radial-flow inflow performance relationships (IPR's) to calculate reservoir performance. An accurate prediction of fractured-well production must be made to design the most economically efficient production configuration. It has been suggested in the literature that a normalized reference curve can be used to generate the IPR's necessary for production-systems analysis. However, this work shows that the reference curve for fractured-well response becomes time-dependent when reservoir boundaries are considered. A general approach for constructing IPR curves is presented, and the use of an unsteady-state fractured-well-production simulator coupled with the production-systems-analysis approach is described. A field case demonstrates the application of this method to fractured wells.

Hunt, J.L. (Halliburton Services (US))

1988-11-01T23:59:59.000Z

406

Modeling interfacial fracture in Sierra.  

SciTech Connect (OSTI)

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

407

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

408

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

409

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

410

Skull fracture vs. accessory sutures: how can we tell the difference?  

E-Print Network [OSTI]

fissure: diagnosis of fracture versus anatomic variants.be performed to identify fractures in suspected child abuse?skull: the diagnosis of fracture. Am J Roentgenol Radium

Sanchez, Thomas; Stewart, Deborah; Walvick, Matthew; Swischuk, Leonard

2010-01-01T23:59:59.000Z

411

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

E-Print Network [OSTI]

New Model of Hydraulic Fracture With an Induced Low Velocityand L. R. Meyer, 1988. Fracture Detectin Using P- Wave andof a Vertical Hydraulic Fracture, Earth Sciences Division,

Nelson, J.T.

2009-01-01T23:59:59.000Z

412

E-Print Network 3.0 - adjacent compression fractures Sample Search...  

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

and triangular columns formed by column-bounding fractures adjacent to inflation-fracture walls... the cooling rate, caus- ing increased fracturing ... Source: Kattenhorn,...

413

Fracture behavior of circumferentially surface-cracked elbows. Technical report, October 1993--March 1996  

SciTech Connect (OSTI)

This report presents the results from Task 2 of the Second International Piping Integrity Research Group (IPIRG-2) program. The focus of the Task 2 work was directed towards furthering the understanding of the fracture behavior of long-radius elbows. This was accomplished through a combined analytical and experimental program. J-estimation schemes were developed for both axial and circumferential surface cracks in elbows. Large-scale, quasi-static and dynamic, pipe-system, elbow fracture experiments under combined pressure and bending loads were performed on elbows containing an internal surface crack at the extrados. In conjunction with the elbow experiments, material property data were developed for the A106-90 carbon steel and WP304L stainless steel elbow materials investigated. A comparison of the experimental data with the maximum stress predictions using existing straight pipe fracture prediction analysis methods, and elbow fracture prediction methods developed in this program was performed. This analysis was directed at addressing the concerns regarding the validity of using analysis predictions developed for straight pipe to predict the fracture stresses of cracked elbows. Finally, a simplified fitting flaw acceptance criteria incorporating ASME B2 stress indices and straight pipe, circumferential-crack analysis was developed.

Kilinski, T.; Mohan, R.; Rudland, D.; Fleming, M. [and others

1996-12-01T23:59:59.000Z

414

Discrete Element Model for Simulations of Early-Life Thermal Fracturing Behaviors in Ceramic Nuclear Fuel Pellets  

SciTech Connect (OSTI)

A discrete element Model (DEM) representation of coupled solid mechanics/fracturing and heat conduction processes has been developed and applied to explicitly simulate the random initiations and subsequent propagations of interacting thermal cracks in a ceramic nuclear fuel pellet during initial rise to power and during power cycles. The DEM model clearly predicts realistic early-life crack patterns including both radial cracks and circumferential cracks. Simulation results clearly demonstrate the formation of radial cracks during the initial power rise, and formation of circumferential cracks as the power is ramped down. In these simulations, additional early-life power cycles do not lead to the formation of new thermal cracks. They do, however clearly indicate changes in the apertures of thermal cracks during later power cycles due to thermal expansion and shrinkage. The number of radial cracks increases with increasing power, which is consistent with the experimental observations.

Hai Huang; Ben Spencer; Jason Hales

2014-10-01T23:59:59.000Z

415

Gamma-ray observations of the Crab Region using a coded-aperture telescope  

SciTech Connect (OSTI)

The region of the Galactic anticenter, including the Crab Nebula, was observed during a balloon flight of the University of New Hampshire Directional Gamma-Ray Telescope employing the coded-aperture imaging technique to image celestial gamma-radiation between 160 keV and 9.3 MeV. The background systematics are treated with a simple and relatively straightforward correction procedure. The results demonstrate that the coded-aperture procedure is a viable approach for imaging not only point sources of radiation, but also extended sources of emission. The results for the Crab's photon spectrum are consistent with a power-law spectrum. Upper limits on the flux levels of line emission at 405 keV and 1050 keV and on the flux from the X-ray binary source A0535 + 26 and diffuse Galactic emission from the anticenter region are derived. 35 references.

Mcconnell, M.L.; Dunphy, P.P.; Forrest, D.J.; Chupp, E.L.; Owens, A.

1987-10-01T23:59:59.000Z

416

Deformation and fracture characteristics of spent Zircaloy fuel cladding  

SciTech Connect (OSTI)

For a better understanding of Zircaloy fuel-rod failure by the pellet-cladding interaction (PCI) phenomenon, a mechanistic study of deformation and fracture behavior of spent power reactor fuel cladding under simulated PCI conditions was conducted. Zircaloy-2 cladding specimens, obtained from fuel assemblies of operating power reactors, were deformed to fracture at 325/sup 0/C by internal gas pressurization in the absence of fission product simulants. Fracture characteristics and microstructures were examined via SEM, TEM, and HVEM. Numerous dislocation tangles and cell structures, observed in TEM specimens of cladding tubes that failed in a ductile manner, were consistent with SEM observations of a limited number of dimples characteristic of microvoid coalescence. A number of brittle-type failures were produced without the influence of fission product simulants. The brittle cracks occurred near the areas compressed by the Swagelok fittings of the internally pressurized tube and propagated from the outer to the inner surface. Since the outer surface was isolated and maintained under a flowing stream of pure helium, it is unlikely that the brittle-type failure was influenced by any fission product traces. SEM fractography of the brittle-type failure revealed a large area of transgranular pseudocleavage with limited areas of ductile fluting, which were similar in appearance to the surfaces produced by in-reactor PCI-type failures. A TEM evaluation of the cladding in the vicinity of the through-wall crack revealed numerous locations that contained an extensive amount of second-phase precipitate (Zr/sub 3/O). We believe that the brittle-type failures of the irradiated spent fuel cladding in the stress rupture experiments are associated with segregation of oxygen, which leads to the formation of the order structure, an immobilization of dislocations, and minimal plastic deformation in the material.

Chung, H.M.; Yaggee, F.L.

1982-09-01T23:59:59.000Z

417

Method for generating small and ultra small apertures, slits, nozzles and orifices  

DOE Patents [OSTI]

A method and device for one or more small apertures, slits, nozzles and orifices, preferably having a high aspect ratio. In one embodiment, one or more alternating layers of sacrificial layers and blocking layers are deposited onto a substrate. Each sacrificial layer is made of a material which preferably allows a radiation to substantially pass through. Each blocking layer is made of a material which substantially blocks the radiation.

Khounsary, Ali M. (Hinsdale, IL)

2012-05-22T23:59:59.000Z

418

IFP V4.0:a polar-reformatting image formation processor for synthetic aperture radar.  

SciTech Connect (OSTI)

IFP V4.0 is the fourth generation of an extraordinarily powerful and flexible image formation processor for spotlight mode synthetic aperture radar. It has been successfully utilized in processing phase histories from numerous radars and has been instrumental in the development of many new capabilities for spotlight mode SAR. This document provides a brief history of the development of IFP, a full exposition of the signal processing steps involved, and a short user's manual for the software implementing this latest iteration.

Eichel, Paul H.

2005-09-01T23:59:59.000Z

419

RF/optical shared aperture for high availability wideband communication RF/FSO links  

DOE Patents [OSTI]

An RF/Optical shared aperture is capable of transmitting and receiving optical signals and RF signals simultaneously. This technology enables compact wide bandwidth communications systems with 100% availability in clear air turbulence, rain and fog. The functions of an optical telescope and an RF reflector antenna are combined into a single compact package by installing an RF feed at either of the focal points of a modified Gregorian telescope.

Ruggiero, Anthony J; Pao, Hsueh-yuan; Sargis, Paul

2014-04-29T23:59:59.000Z

420

Coded aperture imaging with self-supporting uniformly redundant arrays. [Patent application  

DOE Patents [OSTI]

A self-supporting uniformly redundant array pattern for coded aperture imaging. The invention utilizes holes which are an integer times smaller in each direction than holes in conventional URA patterns. A balance correlation function is generated where holes are represented by 1's, nonholes are represented by -1's, and supporting area is represented by 0's. The self-supporting array can be used for low energy applications where substrates would greatly reduce throughput.

Fenimore, E.E.

1980-09-26T23:59:59.000Z

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


421

Coded aperture imaging system optimized for hard x-ray and gamma ray astronomy  

SciTech Connect (OSTI)

A coded aperture imaging system has been designed for the Gamma-Ray Imaging Spectrometer (GRIS). The system is optimized for imaging 511-keV positron-annihilation photons. For a galactic center 511-keV source strength of 10/sup -3/ cm/sup -2/s/sup -1/, the source location accuracy is expected to be +-0.2/sup 0/.

Gehrels, N.; Cline, T.L.; Huters, A.F.; Leventhal, M.; MacCallum, C.J.; Reber, J.D.; Stang, P.D.; Teegarden, B.J.; Tueller, J.

1985-01-01T23:59:59.000Z

422

Remote optical sensing on the nanometer scale with a bowtie aperture nano-antenna on a SNOM fiber tip  

E-Print Network [OSTI]

Plasmonic nano-antennas have proven the outstanding ability of sensing chemical and physical processes down to the nano-meter scale. Sensing is usually achieved within the highly confined optical fields generated resonantly by the nano-antennas, i.e. in contact to the nano-structures. In these paper, We demonstrate the sensing capability of nano-antennas to their larger scale environment, well beyond their plasmonic confinement volume, leading to the concept of 'remote' (non contact) sensing on the nano-meter scale. On the basis of a bowtie-aperture nano-antenna (BNA) integrated at the apex of a SNOM fiber tip, we introduce an ultra-compact, move-able and background-free optical nano-sensor for the remote sensing of a silicon surface (up to distance of 300 nm). Sensitivity of the BNA to its large scale environment is high enough to expect the monitoring and control of the spacing between the nano-antenna and a silicon surface with sub-nano-meter accuracy. This work paves the way towards a new class of nano-po...

Atie, Elie M; Eter, Ali El; Salut, Roland; Nedeljkovic, Dusan; Tannous, Tony; Baida, Fadi I; Grosjean, Thierry

2015-01-01T23:59:59.000Z

423

Measured Radiation and Background Levels During Transmission of Megawatt Electron Beams Through Millimeter Apertures  

SciTech Connect (OSTI)

We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation when the machine is tuned for 130 MeV operation.

Alarcon, Ricardo [Arizona State University, Glendale, AZ (United States); Balascuta, S. [Arizona State University, Glendale, AZ (United States); Benson, Stephen V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Bertozzi, William [Massachusetts Institute of Technology, Cambridge, MA (United States); Boyce, James R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Cowan, Ray [Massachusetts Institute of Technology, Cambridge, MA (United States); Douglas, David R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Evtushenko, Pavel [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Fisher, P. [Massachusetts Institute of Technology, Cambridge, MA (United States); Ihloff, Ernest E. [Hampton University, Hampton, VA (United States); Kalantarians, Narbe [Hampton University, Hampton, VA (United States); Kelleher, Aidan Michael [Massachusetts Institute of Technology, Cambridge, MA (United States); Krossler, W. J. [William and Mary College, Williamsburg, VA (United States); Legg, Robert A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Long, Elena [University of New Hampshire, Durham, NH (United States); Milner, Richard [Massachusetts Institute of Technology, Cambridge, MA (United States); Neil, George R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Ou, Longwu [Massachusetts Institute of Technology, Cambridge, MA (United States); Schmookler, Barack Abraham [Massachusetts Institute of Technology, Cambridge, MA (United States); Tennant, Christopher D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Tschalar, C. [Massachusetts Institute of Technology, Cambridge, MA (United States); Williams, Gwyn P. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Zhang, Shukui [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

2013-11-01T23:59:59.000Z

424

Assessment of radial image distortion and spherical aberration on three-dimensional synthetic aperture particle image velocimetry measurements  

E-Print Network [OSTI]

This thesis presents a numerical study of the effects of radial image distortion and spherical aberration on reconstruction quality of synthetic aperture particle image velocimetry (SAPIV) measurements. A simulated SAPIV ...

Kubaczyk, Daniel Mark

2013-01-01T23:59:59.000Z

425

Design of a near-field coded aperture cameras for high-resolution medical and industrial gamma-ray imaging  

E-Print Network [OSTI]

Coded Aperture Imaging is a technique originally developed for X-ray astronomy, where typical imaging problems are characterized by far-field geometry and an object made of point sources distributed over a mainly dark ...

Accorsi, Roberto, 1971-

2001-01-01T23:59:59.000Z

426

IPIRG programs - advances in pipe fracture technology  

SciTech Connect (OSTI)

This paper presents an overview of the advances made in fracture control technology as a result of the research performed in the International Piping Integrity Research Group (IPIRG) program. The findings from numerous experiments and supporting analyses conducted to investigate the behavior of circumferentially flawed piping and pipe systems subjected to high-rate loading typical of seismic events are summarized. Topics to be discussed include; (1) Seismic loading effects on material properties, (2) Piping system behavior under seismic loads, (3) Advances in elbow fracture evaluations, and (4) {open_quotes}Real{close_quotes} piping system response. The presentation for each topic will be illustrated with data and analytical results. In each case, the state-of-the-art in fracture mechanics prior to the first IPIRG program will be contrasted with the state-of-the-art at the completion of the IPIRG-2 program.

Wilkowski, G.; Olson, R.; Scott, P. [Batelle, Columbus, OH (United States)

1997-04-01T23:59:59.000Z

427

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

E-Print Network [OSTI]

cooling of the fracture surfaces results in a significant opening of the fracture, which would influence the rate of geothermal

Wessling, S.

2009-01-01T23:59:59.000Z

428

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

429

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

430

FRACTURE AND HYDROLOGY DATA FROM FIELD STUDIES AT STRIPA, SWEDEN  

E-Print Network [OSTI]

An Approach to the Fracture Hydrology at Stripa, PreliminaryRocks. On Recent Trends in Hydrology, Special PublicationsDE86 013586 W FRACTURE AND HYDROLOGY DATA FROM FIELD STUDIES

Gale, J.E.

2010-01-01T23:59:59.000Z

431

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...

Nino Penaloza, Andrea

2013-05-01T23:59:59.000Z

432

Development and testing of an advanced acid fracture conductivity apparatus  

E-Print Network [OSTI]

wells. Acid fracturing is a standard practice to increase the production rate and to improve ultimate recovery in carbonate reservoirs. There have been successful cases in most carbonate reservoirs around the world. However acid fracture performance...

Zou, ChunLei

2006-08-16T23:59:59.000Z

433

Fracture Evolution Following a Hydraulic Stimulation within an EGS Reservoir  

Broader source: Energy.gov [DOE]

DOE Geothermal Peer Review 2010 - Presentation. This project will provide the first ever formal evaluation of fracture and fracture flow evolution in an EGS reservoir following a hydraulic stimulation.

434

Fracture Characterization from Scattered Energy: A Case Study  

E-Print Network [OSTI]

We use 3D surface seismic data to determine the presence and the preferred orientation of fracture corridors in a field. The Scattering Index method is proving to be a robust tool for detecting and mapping fracture corridors. ...

Grandi, Samantha K.

2006-01-01T23:59:59.000Z

435

Effectiveness of microseismic monitoring for optimizing hydraulic fracturing in California  

E-Print Network [OSTI]

Hydraulic fracturing has fundamentally changed the oil and gas industry in the past 10 years. Bakersfield, California provides a unique case study because steam injection, a type of hydraulic fracturing, has been used there ...

Alampi, Ann M

2014-01-01T23:59:59.000Z

436

Seismic characterization of fractured reservoirs by focusing Gaussian beams  

E-Print Network [OSTI]

Naturally fractured reservoirs occur worldwide, and they account for the bulk of global oil production. The most important impact of fractures is their influence on fluid flow. To maximize oil production, the characterization ...

Zheng, Yingcai

437

A Bayesian framework for fracture characterization from surface seismic data  

E-Print Network [OSTI]

We describe a methodology for quantitatively characterizing the fractured nature of a hydrocarbon or geothermal reservoir from surface seismic data under a Bayesian inference framework. Fractures provide pathways for fluid ...

Zamanian, S. Ahmad

2012-01-01T23:59:59.000Z

438

Incorporating Rigorous Height Determination into Unified Fracture Design  

E-Print Network [OSTI]

; 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...

Pitakbunkate, Termpan

2010-10-12T23:59:59.000Z

439

Hydraulic Fracture Monitoring: A Jonah Field Case Study  

E-Print Network [OSTI]

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

Seher, T.

2011-01-01T23:59:59.000Z

440

Fractional Diffusion Modeling of Electromagnetic Induction in Fractured Rocks  

E-Print Network [OSTI]

-2 km, a zone where pores and fractures over various length scales are highly complicated. Spatial confinement of fluid or electric charge transport by the fractal geometry gives rise to interesting dynamic processes within the pore space and fractures...

Ge, Jianchao

2014-08-11T23:59:59.000Z

Note: This page contains sample records for the topic "large aperture fractures" 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.


441

Selection of fracture fluid for stimulating tight gas reservoirs  

E-Print Network [OSTI]

..........................................51 6 Water Fracture Fluid Description ..............................................................56 7 Gel Fracture Fluid Description ..................................................................56 8 Proppant Description... Based on Proppant Concentration ........................66 24 Cumulative Frequency Distribution for 3-Year Cumulative Gas Production for Both Groups and Both Treatments (Carthage...

Malpani, Rajgopal Vijaykumar

2007-04-25T23:59:59.000Z

442

Finite Difference Modeling of Seismic Responses to Intersecting Fracture Sets  

E-Print Network [OSTI]

Fractured reservoir characterization is becoming increasingly important for the petroleum industry. Currentmethods for this task are developed based on effectivemedia theory, which assumes the cracks or fractures in a ...

Chi, Shihong

2006-01-01T23:59:59.000Z

443

Fracture Toughness Prediction for MWCNT Reinforced Ceramics  

SciTech Connect (OSTI)

This report describes the development of a micromechanics model to predict fracture toughness of multiwall carbon nanotube (MWCNT) reinforced ceramic composites to guide future experimental work for this project. The modeling work described in this report includes (i) prediction of elastic properties, (ii) development of a mechanistic damage model accounting for matrix cracking to predict the composite nonlinear stress/strain response to tensile loading to failure, and (iii) application of this damage model in a modified boundary layer (MBL) analysis using ABAQUS to predict fracture toughness and crack resistance behavior (R-curves) for ceramic materials containing MWCNTs at various volume fractions.

Henager, Charles H.; Nguyen, Ba Nghiep

2013-09-01T23:59:59.000Z

444

HFIR vessel probabilistic fracture mechanics analysis  

SciTech Connect (OSTI)

The life of the High Flux Isotope Reactor (HFIR) pressure vessel is limited by a radiation induced reduction in the material`s fracture toughness. Hydrostatic proof testing and probabilistic fracture mechanics analyses are being used to meet the intent of the ASME Code, while extending the life of the vessel well beyond its original design value. The most recent probabilistic evaluation is more precise and accounts for the effects of gamma as well as neutron radiation embrittlement. This analysis confirms the earlier estimates of a permissible vessel lifetime of at least 50 EFPY (100 MW).

Cheverton, R.D. [Delta-21 Resources, Inc., Oak Ridge, TN (United States); Dickson, T.L. [Oak Ridge National Lab., TN (United States)

1997-01-01T23:59:59.000Z

445

Compartmentalization analysis using discrete fracture network models  

SciTech Connect (OSTI)

This paper illustrates how Discrete Fracture Network (DFN) technology can serve as a basis for the calculation of reservoir engineering parameters for the development of fractured reservoirs. It describes the development of quantitative techniques for defining the geometry and volume of structurally controlled compartments. These techniques are based on a combination of stochastic geometry, computational geometry, and graph theory. The parameters addressed are compartment size, matrix block size and tributary drainage volume. The concept of DFN models is explained and methodologies to compute these parameters are demonstrated.

La Pointe, P.R.; Eiben, T.; Dershowitz, W. [Golder Associates Inc., Redmond, WA (United States); Wadleigh, E. [Marathon Oil Company, Midland, TX (United States). Mid-Continent Region Production

1997-12-31T23:59:59.000Z

446

Compartmentalization analysis using discrete fracture network models  

SciTech Connect (OSTI)

This paper illustrates how Discrete Fracture Network (DFN) technology can serve as a basis for the calculation of reservoir engineering parameters for the development of fractured reservoirs. It describes the development of quantitative techniques for defining the geometry and volume of structurally controlled compartments. These techniques are based on a combination of stochastic geometry, computational geometry, and graph the theory. The parameters addressed are compartment size, matrix block size and tributary drainage volume. The concept of DFN models is explained and methodologies to compute these parameters are demonstrated.

La Pointe, P.R.; Eiben, T.; Dershowitz, W. [Golder Associates, Redmond, VA (United States); Wadleigh, E. [Marathon Oil Co., Midland, TX (United States)

1997-08-01T23:59:59.000Z

447

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

SciTech Connect (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

448

A CLOSE COMPANION SEARCH AROUND L DWARFS USING APERTURE MASKING INTERFEROMETRY AND PALOMAR LASER GUIDE STAR ADAPTIVE OPTICS  

SciTech Connect (OSTI)

We present a close companion search around 16 known early L dwarfs using aperture masking interferometry with Palomar laser guide star adaptive optics (LGS AO). The use of aperture masking allows the detection of close binaries, corresponding to projected physical separations of 0.6-10.0 AU for the targets of our survey. This survey achieved median contrast limits of {Delta}K {approx} 2.3 for separations between 1.2 {lambda}/D-4{lambda}/D and {Delta}K {approx} 1.4 at 2/3 {lambda}/D. We present four candidate binaries detected with moderate-to-high confidence (90%-98%). Two have projected physical separations less than 1.5 AU. This may indicate that tight-separation binaries contribute more significantly to the binary fraction than currently assumed, consistent with spectroscopic and photometric overluminosity studies. Ten targets of this survey have previously been observed with the Hubble Space Telescope as part of companion searches. We use the increased resolution of aperture masking to search for close or dim companions that would be obscured by full aperture imaging, finding two candidate binaries. This survey is the first application of aperture masking with LGS AO at Palomar. Several new techniques for the analysis of aperture masking data in the low signal-to-noise regime are explored.

Bernat, David [Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States); Bouchez, Antonin H.; Cromer, John L.; Dekany, Richard G.; Moore, Anna M. [California Institute of Technology, Pasadena, CA 91125 (United States); Ireland, Michael; Tuthill, Peter [Sydney Institute for Astrophysics, School of Physics, University of Sydney (Australia); Martinache, Frantz [National Astronomical Observatory of Japan, Subaru Telescope, Hilo, HI 96720 (United States); Angione, John; Burruss, Rick S.; Guiwits, Stephen R.; Henning, John R.; Hickey, Jeff; Kibblewhite, Edward; McKenna, Daniel L.; Petrie, Harold L.; Roberts, Jennifer; Shelton, J. Chris; Thicksten, Robert P.; Trinh, Thang [Palomar Laser Guide Star Adaptive Optics Team, Palomar Observatory, California Institute of Technology, Palomar Mountain, CA 92060 (United States)

2010-06-01T23:59:59.000Z

449

Experimental and Analytical Research on Fracture Processes in ROck  

SciTech Connect (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

450

New fluids help increase effectiveness of hydraulic fracturing  

SciTech Connect (OSTI)

It is important to choose the most effective fluid for hydraulic fracturing a particular formation. Fracturing fluids are used to initiate formation parting, extend the fracture into the reservoir, and to transport and distribute proppant. This paper discusses the fundamental of fluid types, viscosifiers, and fluid rheology.

Ebinger, C.D.; Hunt, E.

1989-06-05T23:59:59.000Z

451

Role of seepage forces on hydraulic fracturing and failure patterns  

E-Print Network [OSTI]

Role of seepage forces on hydraulic fracturing and failure patterns Alexander Rozhko Thesis September 2007 #12;ii Role of seepage forces on hydraulic fracturing and failure patterns Abstract. The mechanical role of seepage forces on hydraulic fracturing and failure patterns was studied both

Paris-Sud XI, Université de

452

HYDRAULIC STIMULATION OF NATURAL FRACTURES AS REVEALED BY INDUCED MICROEARTHQUAKES,  

E-Print Network [OSTI]

-1- HYDRAULIC STIMULATION OF NATURAL FRACTURES AS REVEALED BY INDUCED MICROEARTHQUAKES, CARTHAGE, December, 2001 Manuscript # 01066 LAUR# 01-1204 #12;Hydraulic Stimulation of Natural Fractures -2- ABSTRACT We have produced a high-resolution microseismic image of a hydraulic fracture stimulation

453

Modeling Turbulent Hydraulic Fracture Near a Free Surface  

E-Print Network [OSTI]

Modeling Turbulent Hydraulic Fracture Near a Free Surface Victor C. Tsai Seismological Laboratory consider a hydraulic fracture problem in which the crack grows parallel to a free surface, subject to fully components. wall Wall shear stress. ^· Non-dimensionalized ·. 1 Introduction Hydraulic fracture has been

454

Modeling Turbulent Hydraulic Fracture Near a Free Surface  

E-Print Network [OSTI]

Modeling Turbulent Hydraulic Fracture Near a Free Surface Victor C. Tsai Seismological Laboratory consider a hydraulic fracture problem in which the crack grows parallel to a free surface, subject to fully components. ^· Non-dimensionalized ·. 1 Introduction Hydraulic fracture has been studied for many years

455

Poroelastic modeling of fracture-seismic wave interaction  

SciTech Connect (OSTI)

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

Nakagawa, Seiji

2008-08-15T23:59:59.000Z

456

San Juan Fracture Characterization Project: Status and current results  

SciTech Connect (OSTI)

The overall objectives of this report are to extend current state-of-the-art 3-D imaging to extract the optimal information for fracture quantification and to develop next generation capability in fracture imaging for true 3-D imaging of the static and dynamic fracture properties.

Majer, E.L.; Daley, T.M.; Myer, L.R.; Nihei, K.; Queen, J.; Sinton, J.; Murphy, J.; Fortuna, M.; Lynn, H.B.; Imhoff, M.A.; Wilson, R.

2001-02-26T23:59:59.000Z

457

Estimating Major and Minor Natural Fracture Patterns in Gas  

E-Print Network [OSTI]

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

Mohaghegh, Shahab

458

CLEAVAGE FRACTURE MICROMECHANISMS RELATED TO WPS EFFECT IN RPV STEEL  

E-Print Network [OSTI]

CLEAVAGE FRACTURE MICROMECHANISMS RELATED TO WPS EFFECT IN RPV STEEL S. R. Bordet1 , B. Tanguy1 , S by warm pre-stress (WPS) on the cleavage fracture micromechanisms of a 18MND5 (A533B) reactor pressure vessel (RPV) steel. In this purpose, different WPS fracture test results obtained on compact tensile (CT

Boyer, Edmond

459

Introduction Fracture at small length scales is a concern  

E-Print Network [OSTI]

Introduction Fracture at small length scales is a concern in many advanced technologies. Micro. These constrained geometries localize cracking so that fracture may not compromise the structural integrity functions. For example, lo- calized fracture of a dielectric film adjacent to a conducting line

Suo, Zhigang

460

Scaling of fracture length and distributed damage Vladimir Lyakhovsky  

E-Print Network [OSTI]

Scaling of fracture length and distributed damage Vladimir Lyakhovsky The Institute of Earth space scaling except linear relations between fracture length and displacements and thus the determination theoretically of the strength of a body or structure directly. Self-similarity of a fracture

Lyakhovsky, Vladimir

Note: This page contains sample records for the topic "large aperture fractures" 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.


461

Fracture patterns in thin films and multilayers Alex A. Volinsky  

E-Print Network [OSTI]

Fracture patterns in thin films and multilayers Alex A. Volinsky University of South Florida, excessive residual and externally applied stresses cause film fracture. In the case of tensile stress is the key for causing thin film fracture, either in tension, or compression, it is the influence

Volinsky, Alex A.

462

Monitoring of Fracture Cri0cal Steel Bridges  

E-Print Network [OSTI]

#12;Monitoring of Fracture Cri0cal Steel Bridges: Acous0c Emission Sensors Fracture System Needs to Iden0fy: · Crack Ini0a0on · Crack Propaga0on · Weld Fracture Advanced Warning of Structural Distress #12;Technology Selec0on: Acous0c

Minnesota, University of

463

Structured Deformations as Energy Minimizers in Models of Fracture and  

E-Print Network [OSTI]

Structured Deformations as Energy Minimizers in Models of Fracture and Hysteresis R. Choksi and for a bar experiencing both smooth exten- sion and macroscopic fractures then are determined, and applications to the shearing of single crystals and to the cohesive fracture of solids are discussed. Yield

464

Automatic Fracture Reduction Thomas Albrecht and Thomas Vetter  

E-Print Network [OSTI]

Automatic Fracture Reduction Thomas Albrecht and Thomas Vetter University of Basel Abstract. We segmented from CT scans. The result of this virtual fracture reduction is intended to be used an operation plan. We propose to achieve automatic fracture reduction by fitting the bone fragments

Vetter, Thomas

465

Geometric fracture modeling in BOLT Jeffrey Hellrung1  

E-Print Network [OSTI]

Geometric fracture modeling in BOLT Jeffrey Hellrung1 Andrew Selle2 Arthur Shek2 Eftychios Sifakis1 from the un-fractured model. 2 Crack geometry generation The input to our system consists of a closed triangulated surface defining the (uncut) solid object to be fractured and one or more ad- ditional

Liblit, Ben

466

Fracture Toughness of MDF and other Materials with Fiber Bridging  

E-Print Network [OSTI]

Fracture Toughness of MDF and other Materials with Fiber Bridging Noah Matsumoto and John A. Nairn* ABSTRACT We measured the fracture toughness of MDF panels with two different densities by using crack propagation experiments and energy-based fracture mechanics. The two challenges were to identify the energy

Nairn, John A.

467

EXPERIMENTAL INVESTIGATION OF BOILING HEAT CONVECTION IN A FRACTURE  

E-Print Network [OSTI]

EXPERIMENTAL INVESTIGATION OF BOILING HEAT CONVECTION IN A FRACTURE A REPORT SUBMITTED between heat conduction and heat convection with boiling flow in a rock fracture. An experimental coefficient. This coefficient is the proportionality factor between the heat flux to a fracture surface

Stanford University

468

SCALING OF FRACTURE SYSTEMS IN GEOLOGICAL MEDIA E. Bonnet,1  

E-Print Network [OSTI]

SCALING OF FRACTURE SYSTEMS IN GEOLOGICAL MEDIA E. Bonnet,1 O. Bour,2 N. E. Odling,1,3 P. Davy,2 I. Main,4 P. Cowie,4 and B. Berkowitz5 Abstract. Scaling in fracture systems has become an active field spread widely through the literature. Although it is rec- ognized that some fracture systems are best

Cowie, Patience

469

Fibre Based Modeling of Wood Dynamics and Fracture  

E-Print Network [OSTI]

Fibre Based Modeling of Wood Dynamics and Fracture by Sean Meiji Sutherland B.Sc., The University for the simulation of the dynamics and fracturing char- acteristics of wood, specifically its anisotropic behaviour bundles of fibres. Additionally, we describe the conditions under which fracture occurs in the material

Bridson, Robert

470

In vitro fracture toughness of human dentin V. Imbeni,1  

E-Print Network [OSTI]

In vitro fracture toughness of human dentin V. Imbeni,1 R. K. Nalla,1 C. Bosi,1 J. H. Kinney,2 R. O August 2002 Abstract: The in vitro fracture toughness of human dentin has been reported measured crit- ical stress intensity, Kc, for the onset of unstable fracture along an orientation

Ritchie, Robert

471

Fracture surface energy of the Punchbowl fault, San Andreas system  

E-Print Network [OSTI]

Fracture surface energy of the Punchbowl fault, San Andreas system Judith S. Chester1 , Frederick M. Chester1 & Andreas K. Kronenberg1 Fracture energy is a form of latent heat required to create weakening1­3 . Fracture energy has been estimated from seismological and experimental rock deformation data4

Chester, Frederick M.

472

THE EFFECT OF SURFACE TENSION IN MODELING INTERFACIAL FRACTURE  

E-Print Network [OSTI]

THE EFFECT OF SURFACE TENSION IN MODELING INTERFACIAL FRACTURE By Tsvetanka Sendova and Jay R Fracture Tsvetanka Sendova and Jay R. Walton Institute for Mathematics and Its Applications, University@math.tamu.edu Abstract. In this article the problem of an interface fracture between two isotropic linear elas- tic

473

The use of seismic anisotropy for characterizing subsurface fracture ori-  

E-Print Network [OSTI]

The use of seismic anisotropy for characterizing subsurface fracture ori- entations and intensity anisotropy as a routine technique for fracture characterization is partly because of its inability to pro- vide information about sizes and vol- ume of fractures. Although both grain-scale micro

Edinburgh, University of

474

6. Fracture mechanics lead author: J, R. Rice  

E-Print Network [OSTI]

6. Fracture mechanics lead author: J, R. Rice Division of Applied Sciences, Harvard University. F. Shih, and the ASME/AMD Technical Committee on Fracture Mechanics, pro- vided by A. S. Argon, S. N, W. D. Stuart, and R. Thomson. 6.0 ABSTRACT Fracture mechanics is an active research field

475

Femoral neck fracture prediction by anisotropic yield criteria  

E-Print Network [OSTI]

Femoral neck fracture prediction by anisotropic yield criteria M. Tellache a , b , M. Pithioux and increases its porosity. Hip fractures are the more recurrent consequences of osteoporosis, and are the cause of morbidity and increase the rate of mortality. The fracture risk due to osteoporosis, is undertaken with Dual

Paris-Sud XI, Université de

476

Creation and Impairment of Hydraulic Fracture Conductivity in Shale Formations  

E-Print Network [OSTI]

Multi-stage hydraulic fracturing is the key to the success of many shale gas and shale oil reservoirs. The main objectives of hydraulic fracturing in shale are to create artificial fracture networks that are conductive for oil and gas flow...

Zhang, Junjing

2014-07-10T23:59:59.000Z

477

Time-resolved measurement of photon emission during fast crack propagation in three-point bending fracture of silica glass and soda lime glass  

SciTech Connect (OSTI)

Simultaneous time-resolved measurements of photon emission (PE) and fast crack propagation upon bending fracture were conducted in silica glass and soda lime glass. Observation of fracture surfaces revealed that macroscopic crack propagation behavior was similar between the silica glass and soda lime glass when fracture loads for these specimens were comparable and cracks propagated without branching. However, a large difference in the PE characteristics was found between the two glasses. In silica glass, PE (645–655?nm) was observed during the entire crack propagation process, whereas intense PE (430–490?nm and 500–600?nm) was observed during the initial stages of propagation. In contrast, only weak PE was detected in soda lime glass. These results show that there is a large difference in the atomic processes involved in fast crack propagation between these glasses, and that PE can be used to study brittle fracture on the atomic scale.

Shiota, Tadashi, E-mail: tshiota@ceram.titech.ac.jp; Sato, Yoshitaka; Yasuda, Kouichi [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1-S7-13 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)] [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1-S7-13 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)

2014-03-10T23:59:59.000Z

478

Aperture lamp  

DOE Patents [OSTI]

A discharge lamp includes means for containing a light emitting fill, the fill being capable of absorbing light at one wavelength and re-emitting the light at a different wavelength, the light emitted from the fill having a first spectral power distribution in the absence of reflection of light back into the fill; means for exciting the fill to cause the fill to emit light; and means for reflecting some of the light emitted by the fill back into the fill while allowing some light to exit, the exiting light having a second spectral power distribution with proportionately more light in the visible region as compared to the first spectral power distribution, wherein the light re-emitted by the fill is shifted in wavelength with respect to the absorbed light and the magnitude of the shift is in relation to an effective optical path length. Another discharge lamp includes an envelope; a fill which emits light when excited disposed in the envelope; a source of excitation power coupled to the fill to excite the fill and cause the fill to emit light; and a reflective ceramic structure disposed around the envelope and defining an light emitting opening, wherein the structure comprises a sintered body built up directly on the envelope and made from a combination of alumina and silica.

MacLennan, Donald A. (Gaithersburg, MD); Turner, Brian P. (Damascus, MD)

2003-01-01T23:59:59.000Z

479

Naturally fractured tight gas reservoir detection optimization  

SciTech Connect (OSTI)

In March, work continued on characterizing probabilities for determining natural fracturing associated with the GGRB for the Upper Cretaceous tight gas plays. Structural complexity, based on potential field data and remote sensing data was completed. A resource estimate for the Frontier and Mesa Verde play was also completed. Further, work was also conducted to determine threshold economics for the play based on limited current production in the plays in the Wamsutter Ridge area. These analyses culminated in a presentation at FETC on 24 March 1999 where quantified natural fracture domains, mapped on a partition basis, which establish ''sweet spot'' probability for natural fracturing, were reviewed. That presentation is reproduced here as Appendix 1. The work plan for the quarter of January 1, 1999--March 31, 1999 comprised five tasks: (1) Evaluation of the GGRB partitions for structural complexity that can be associated with natural fractures, (2) Continued resource analysis of the balance of the partitions to determine areas with higher relative gas richness, (3) Gas field studies, (4) Threshold resource economics to determine which partitions would be the most prospective, and (5) Examination of the area around the Table Rock 4H well.

NONE

1999-04-30T23:59:59.000Z

480

Boiling Radial Flow in Fractures of Varying  

E-Print Network [OSTI]

the surface, within the matrix. The depth of boiling was a function of injection rate, thermal power supplied 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

Stanford University

Note: This page contains sample records for the topic "large aperture fractures" 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.


481

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

E-Print Network [OSTI]

) ............................................................................ 51 Figure B.9: Fracture Conductivity Behavior (Polymer Concentration = 50 lb/Mgal and Gas Rate = 0.5 slm) ............................................................................ 52 Figure B.10: Fracture Conductivity Behavior (Polymer... documented in API RP-61 (1989). The recommended conditions and procedure for the test includes loading a known proppant concentration (generally 2 lb/ft2) uniformly between two steel pistons at ambient temperature, maintaining closure stress for 15 minutes...

Marpaung, Fivman

2008-10-10T23:59:59.000Z

482

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

E-Print Network [OSTI]

) ............................................................................ 51 Figure B.9: Fracture Conductivity Behavior (Polymer Concentration = 50 lb/Mgal and Gas Rate = 0.5 slm) ............................................................................ 52 Figure B.10: Fracture Conductivity Behavior (Polymer... documented in API RP-61 (1989). The recommended conditions and procedure for the test includes loading a known proppant concentration (generally 2 lb/ft2) uniformly between two steel pistons at ambient temperature, maintaining closure stress for 15 minutes...

Marpaung, Fivman

2009-05-15T23:59:59.000Z

483

Interference Fracturing: Non-Uniform Distributions of Perforation Clusters that Promote Simultaneous Growth of Multiple Hydraulic Fractures  

E-Print Network [OSTI]

Simultaneous Growth of Multiple Hydraulic Fractures A.P. Peirce, University of British Columbia and A.P. Bunger in horizontal well stimulation is the generation of hydraulic fractures (HFs) from all perforation clusters shadowing" that refers to suppression of some hydraulic fractures by the compressive stresses exerted

Peirce, Anthony

484

A Triple-Porosity Model for Fractured Horizontal Wells  

E-Print Network [OSTI]

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

Alahmadi, Hasan Ali H.

2010-10-12T23:59:59.000Z

485

Analysis of error in using fractured gas well type curves for constant pressure production  

E-Print Network [OSTI]

of normalized time and normalized cumulative production is a large improvement over using a constant evaluation pressure. 0 imens ion less cumulative production type curves are particularly useful in modeling production for economic projections, such as re... of MASTER OF SCIENCE May 1987 Major Subject: Petroleum Engineering ANALYSIS OF ERROR IN USING FRACTURED GAS WELL TYPE CURVES FOR CONSTANT PRESSURE PRDDUCTION A Thesis by DAVID WAYNE SCHKADE Approved as to style and content by: S. A. Ho lditch...

Schkade, David Wayne

1987-01-01T23:59:59.000Z

486

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

SciTech Connect (OSTI)

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

Wood, James R.; Harrison, William B.

2002-12-02T23:59:59.000Z

487

Advanced hydraulic fracturing methods to create in situ reactive barriers  

SciTech Connect (OSTI)

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

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

1997-12-31T23:59:59.000Z

488

Ion funnel with extended mass range and reduced conductance limit aperture  

DOE Patents [OSTI]

An improved ion funnel design is disclosed that decreases the axial RF (parasite) fields at the ion funnel exit. This is achieved by addition of one or more compensation electrodes after the conductance limit electrode. Various RF voltage profiles may be applied to the various electrodes minimizing the parasite axial potential wells. The smallest RF aperture that serves as the conductance limiting electrode is further reduced over standard designs. Overall, the ion funnel improves transmission ranges of both low m/z and high m/z ions, reducing RF activation of ions and decreasing the gas load to subsequent differential pumping stages.

Tolmachev, Aleksey V. (Richland, WA); Smith, Richard D. (Richland, WA)

2008-04-01T23:59:59.000Z

489

Correction of motion measurement errors beyond the range resolution of a synthetic aperture radar  

DOE Patents [OSTI]

Motion measurement errors that extend beyond the range resolution of a synthetic aperture radar (SAR) can be corrected by effectively decreasing the range resolution of the SAR in order to permit measurement of the error. Range profiles can be compared across the slow-time dimension of the input data in order to estimate the error. Once the error has been determined, appropriate frequency and phase correction can be applied to the uncompressed input data, after which range and azimuth compression can be performed to produce a desired SAR image.

Doerry, Armin W. (Albuquerque, NM); Heard, Freddie E. (Albuquerque, NM); Cordaro, J. Thomas (Albuquerque, NM)

2008-06-24T23:59:59.000Z

490

A novel synthetic aperture technique for breast tomography with toroidal arrays  

SciTech Connect (OSTI)

Ultrasound is commonly used as an adjunct to mammography for diagnostic evaluation of suspicions arising from breast cancer screening. As an alternative to conventional sonography that uses hand-held transducers, toroidal array probes that encircle the breast immersed in a water bath have been investigated for ultrasound tomography. This paper introduces a new method for three-dimensional synthetic aperture diffraction tomography that maximizes the resolution in the scanning direction and provides quantitative reconstructions of the acoustic properties of the object. The method is validated by means of numerical simulations.

Huang, Lianjie [Los Alamos National Laboratory; Simonetti, Francesco [IMPERIAL COLLEGE

2009-01-01T23:59:59.000Z

491

Development of Nb3Sn 11 T single aperture demonstrator dipole for LHC upgrades  

SciTech Connect (OSTI)

The LHC collimation upgrade foresees additional collimators installed in dispersion suppressor regions. To obtain the necessary space for the collimators, a solution based on the substitution of LHC main dipoles for stronger dipoles is being considered. CERN and FNAL have started a joint program to demonstrate the feasibility of Nb{sub 3}Sn technology for this purpose. The goal of the first phase is the design and construction of a 2-m long single-aperture demonstrator magnet with a nominal field of 11 T at 11.85 kA with 20% margin. This paper describes the magnetic and mechanical design of the demonstrator magnet and summarizes its design parameters.

Zlobin, A.V.; Apollinari, G.; Andreev, N.; Barzi, E.; Kashikhin, V.V.; Nobrega, f.; Novitski, I.; /Fermilab; Auchmann, B.; Karppinen, M.; Rossi, L.; /CERN

2011-03-01T23:59:59.000Z

492

Temperature-dependent void-sheet fracture in Al-Cu-Mg-Ag-Zr  

SciTech Connect (OSTI)

Temperature-dependent initiation fracture toughness and stable crack growth resistance are important attributes of next-generation aluminum alloys for airframe applications such as the high speed civil transport. Previous research showed that tensile fracture strain increases as temperature increases for AA2519 with Mg and Ag additions, because the void-sheet coalescence stage of microvoid fracture is retarded. The present work characterizes intravoid-strain localization (ISL) between primary voids at large constituents and secondary-void nucleation at small dispersoids, two mechanisms that may govern the temperature dependence of void sheeting. Most dispersoids nucleate secondary voids in an ISL band at 25 C, promoting further localization, while dispersoid-void nucleation at 150 C is greatly reduced. Increased strain-rate hardening with increasing temperature does not cause this behavior. Rather, a stress relaxation model predicts that flow stress and strain hardening decrease with increasing temperature or decreasing strain rate due to a transition from dislocation accumulation to diffusional relaxation around dispersoids. This transition to softening causes a sharp increase in the model-predicted applied plastic strain necessary for dispersoid/matrix interface decohesion. This reduced secondary-void nucleation and reduced ISL at elevated temperature explain retarded void sheeting and increased fracture strain.

Haynes, M.J. [Texas Instruments, Inc., Attleboro, MA (United States); Gangloff, R.P. [Univ. of Virginia, Charlottesville, VA (United States). Dept. of Materials Science and Engineering

1998-06-01T23:59:59.000Z

493

Naturally fractured reservoirs contain a significant amount of the world oil reserves. A number of these reservoirs contain several  

E-Print Network [OSTI]

Summary Naturally fractured reservoirs contain a significant amount of the world oil reserves. A number of these reservoirs contain several billion barrels of oil. Accurate and efficient reservoir this implementation has led to a unique and powerful reservoir simulator that can be used by small and large oil

Arbogast, Todd

494

Impact fracture behavior of HT9 duct  

SciTech Connect (OSTI)

Ferritic alloys are known to undergo a ductile-brittle transition as the test temperature is decreased. This inherent problem has limited their applications to reactor component materials subjected to low neutron exposures. However, the excellent resistance to void swelling exhibited by these alloys has led to choosing the materials as candidate materials for fast and fusion reactor applications. Despite the ductile-brittle transition problem, results show that the materials exhibit superior resistance to fracture under very high neutron fluences at irradiation temperatures above 380{degrees}C. Impact testing on FFTF duct sections of HT9 indicates that HT9 ducts have adequate fracture toughness at much higher temperatures for handling operations at room temperature and refueling operations.

Huang, F.H. [Westinghouse Hanford Co., Richland, WA (United States); Gelles, D.S. [Pacific Northwest Lab., Richland, WA (United States)

1994-07-01T23:59:59.000Z

495

Fracture simulation for zirconia toughened alumina microstructure  

E-Print Network [OSTI]

Purpose - The purpose of this paper is to describe finite element modelling for fracture and fatigue behaviour of zirconia toughened alumina microstructures. Design/methodology/approach - A two-dimensional finite element model is developed with an actual $Al{_2}O{_3}$ - 10 vol% $ZrO{_2}$ microstructure. A bilinear, time-independent cohesive zone law is implemented for describing fracture behaviour of grain boundaries. Simulation conditions are similar to those found at contact between a head and a cup of hip prosthesis. Residual stresses arisen from the mismatch of thermal coefficient between grains are determined. Then, effects of a micro-void and contact stress magnitude are investigated with models containing residual stresses. For the purpose of simulating fatigue behaviour, cyclic loadings are applied to the models. Findings - Results show that crack density is gradually increased with increasing magnitude of contact stress or number of fatigue cycles. It is also identified that a micro-void brings about...

Kim, Kyungmok; Forest, Bernard

2013-01-01T23:59:59.000Z

496

Naturally fractured tight gas reservoir detection optimization  

SciTech Connect (OSTI)

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

NONE

1999-06-01T23:59:59.000Z

497

Characterization of fracture networks for fluid flow analysis  

SciTech Connect (OSTI)

The analysis of fluid flow through fractured rocks is difficult because the only way to assign hydraulic parameters to fractures is to perform hydraulic tests. However, the interpretation of such tests, or ''inversion'' of the data, requires at least that we know the geometric pattern formed by the fractures. Combining a statistical approach with geophysical data may be extremely helpful in defining the fracture geometry. Cross-hole geophysics, either seismic or radar, can provide tomograms which are pixel maps of the velocity or attenuation anomalies in the rock. These anomalies are often due to fracture zones. Therefore, tomograms can be used to identify fracture zones and provide information about the structure within the fracture zones. This structural information can be used as the basis for simulating the degree of fracturing within the zones. Well tests can then be used to further refine the model. Because the fracture network is only partially connected, the resulting geometry of the flow paths may have fractal properties. We are studying the behavior of well tests under such geometry. Through understanding of this behavior, it may be possible to use inverse techniques to refine the a priori assignment of fractures and their conductances such that we obtain the best fit to a series of well test results simultaneously. The methodology described here is under development and currently being applied to several field sites. 4 refs., 14 figs.

Long, J.C.S.; Billaux, D.; Hestir, K.; Majer, E.L.; Peterson, J.; Karasaki, K.; Nihei, K.; Gentier, S.; Cox, L.

1989-06-01T23:59:59.000Z

498

How intense quality control improves hydraulic fracturing  

SciTech Connect (OSTI)

Not unlike the subject of Forced Closure, Intense Quality Control is probably misnamed. What actually is discussed in this article is pilot testing of the fracturing fluids actually pumped at in-situ conditions of temperature and shear. Presented here is development of the need for onsite testing, equipment used, shear and viscosity curves from several jobs showing what went wrong that would otherwise not have been known, and a discussion of borate gel fluids.

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