National Library of Energy BETA

Sample records for large aperture fractures

  1. Finding Large Aperture Fractures in Geothermal Resource Areas...

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

    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...

    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...

  3. Finding Large Aperture Fractures in Geothermal Resource Areas...

    Open Energy Info (EERE)

    Fractures in Geothermal Resource Areas Using a Three-Component Long-Offset Surface Seismic Survey Geothermal Project Jump to: navigation, search Last modified on July 22, 2011....

  4. Large aperture optical switching devices

    SciTech Connect (OSTI)

    Goldhar, J.; Henesian, M.A.

    1983-12-12

    We have developed a new approach to constructing large aperture optical switches for next generation inertial confinement fusion lasers. A transparent plasma electrode formed in low pressure ionized gas acts as a conductive coating to allow the uniform charging of the optical faces of an electro-optic material. In this manner large electric fields can be applied longitudinally to large aperture, high aspect ratio Pockels cells. We propose a four-electrode geometry to create the necessary high conductivity plasma sheets, and have demonstrated fast (less than 10 nsec) switching in a 5x5 cm aperture KD*P Pockels cell with such a design. Detaid modelling of Pockels cell performance with plasma electrodes has been carried out for 15 and 30 cm aperture designs.

  5. Fracture aperture reconstruction and determination of hydrological properties: a

    E-Print Network [OSTI]

    Toussaint, Renaud

    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

  6. Large aperture diffractive space telescope

    DOE Patents [OSTI]

    Hyde, Roderick A. (Livermore, CA)

    2001-01-01

    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.

  7. Application of a geocentrifuge and sterolithographically fabricated apertures to multiphase flow in complex fracture apertures.

    SciTech Connect (OSTI)

    Glenn E. McCreery; Robert D. Stedtfeld; Alan T. Stadler; Daphne L. Stoner; Paul Meakin

    2005-09-01

    A geotechnical centrifuge was used to investigate unsaturated multiphase fluid flow in synthetic fracture apertures under a variety of flow conditions. The geocentrifuge subjected the fluids to centrifugal forces allowing the Bond number to be systematically changed without adjusting the fracture aperture of the fluids. The fracture models were based on the concept that surfaces generated by the fracture of brittle geomaterials have a self-affine fractal geometry. The synthetic fracture surfaces were fabricated from a transparent epoxy photopolymer using sterolithography, and fluid flow through the transparent fracture models was monitored by an optical image acquisition system. Aperture widths were chosen to be representative of the wide range of geological fractures in the vesicular basalt that lies beneath the Idaho Nation Laboratory (INL). Transitions between different flow regimes were observed as the acceleration was changed under constant flow conditions. The experiments showed the transition between straight and meandering rivulets in smooth walled apertures (aperture width = 0.508 mm), the dependence of the rivulet width on acceleration in rough walled fracture apertures (average aperture width = 0.25 mm), unstable meandering flow in rough walled apertures at high acceleration (20g) and the narrowing of the wetted region with increasing acceleration during the penetration of water into an aperture filled with wetted particles (0.875 mm diameter glass spheres).

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

    SciTech Connect (OSTI)

    Detwiler, Russell

    2014-04-30

    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.

  9. Advances in optical materials for large aperture lasers

    SciTech Connect (OSTI)

    Stokowski, S.E.; Lowdermilk, W.H.; Marchi, F.T.; Swain, J.E.; Wallerstein, E.P.; Wirtenson, G.R.

    1981-12-15

    Lawrence Livermore National Laboratory (LLNL) is using large aperture Nd: glass lasers to investigate the feasibility of inertial confinement fusion. In our experiments high power laser light is focussed onto a small (100 to 500 micron) target containing a deuterium-tritium fuel mixture. During the short (1 to 5 ns) laser pulse the fuel is compressed and heated, resulting in fusion reactions. The generation and control of the powerful laser pulses for these experiments is a challenging scientific and engineering task, which requires the development of new optical materials, fabrication techniques, and coatings. LLNL with the considerable cooperation and support from the optical industry, where most of the research and development and almost all the manufacturing is done, has successfully applied several new developments in these areas.

  10. Cavity-excited Huygens' metasurface antennas: near-unity aperture efficiency from arbitrarily-large apertures

    E-Print Network [OSTI]

    Epstein, Ariel; Eleftheriades, George V

    2015-01-01

    One of the long-standing problems in antenna engineering is the realization of highly-directive beams using low-profile devices. In this paper we provide a solution to this problem by means of Huygens' metasurfaces (HMSs), based on the equivalence principle. This principle states that a given excitation can be transformed to a desirable aperture field by inducing suitable electric and magnetic surface currents. Building on this concept, we propose and demonstrate cavity-excited HMS antennas, where the single-source cavity excitation is designed to optimize aperture illumination, while the HMS facilitates the current distribution that ensures phase purity of aperture fields. The HMS breaks the coupling between the excitation and radiation spectrum typical to standard partially-reflecting surfaces, allowing tailoring of the aperture properties to produce a desirable radiation pattern. As shown, a single semianalytical formalism can be followed to achieve control of a variety of radiation features, such as the d...

  11. 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 Home Page on QA:QAsource History View New PagesSustainable Urban Transport Jump to: navigation, search Tool SummaryThree-Component

  12. 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:FinancingPetroleum12, 2015Executive Order14,EnergyFinancing and Investing

  13. 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:FinancingPetroleum12, 2015Executive Order14,EnergyFinancing and InvestingThree-Component

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

    E-Print Network [OSTI]

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

    2011-01-01

    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...

  15. Orientation Estimation for Multiple Large Fractures by Scattering Energy

    E-Print Network [OSTI]

    Zhang, Yang

    2006-01-01

    We have done the numerical modeling of seismic response to multiple sets of vertical large fractures by using finite-difference method (FD), which can easily handle media with monoclinic anisotropy. We consider three types ...

  16. A cryogenic rotation stage with a large clear aperture for a half-wave plate

    E-Print Network [OSTI]

    Bryan, Sean; Amiri, Mandana; Benton, Steven; Bihary, Richard; Bock, James; Bond, J Richard; Chiang, H Cynthia; Contaldi, Carlo; Crill, Brendan; Dore, Olivier; Elder, Benjamin; Filippini, Jeffrey; Fraisse, Aurelien; Gambrel, Anne; Gandilo, Natalie; Gudmundsson, Jon; Hasselfield, Matthew; Halpern, Mark; Hilton, Gene; Holmes, Warren; Hristov, Viktor; Irwin, Kent; Jones, William; Kermish, Zigmund; Lawrie, Craig; MacTavish, Carrie; Mason, Peter; Megerian, Krikor; Moncelsi, Lorenzo; Montroy, Thomas; Morford, Tracy; Nagy, Johanna; Netterfield, C Barth; Rahlin, Alexandra S; Reintsema, Carl; Riley, Daniel C; Ruhl, John; Runyan, Marcus; Saliwanchik, Benjamin; Shariff, Jamil; Soler, Juan; Trangsrud, Amy; Tucker, Carole; Tucker, Rebecca; Turner, Anthony; Wen, Shyang; Wiebe, Donald; Young, Edward

    2015-01-01

    We describe the cryogenic half-wave plate rotation mechanisms built for and used in Spider, a polarization-sensitive balloon-borne telescope array that observed the Cosmic Microwave Background at 95 GHz and 150 GHz during a stratospheric balloon flight from Antarctica in January 2015. The mechanisms operate at liquid helium temperature in flight. A three-point contact design keeps the mechanical bearings relatively small but allows for a large (305 mm) diameter clear aperture. A worm gear driven by a cryogenic stepper motor allows for precise positioning and prevents undesired rotation when the motors are depowered. A custom-built optical encoder system monitors the bearing angle to an absolute accuracy of 0.1 degrees. The system performed well in Spider during its successful 16 day flight.

  17. MULTI-PHASE FRACTURE-MATRIX INTERACTIONS UNDER STRESS CHANGES

    SciTech Connect (OSTI)

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

    2005-06-15

    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 studied, 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.

  18. Active and passive acoustic imaging inside a large-scale polyaxial hydraulic fracture test

    SciTech Connect (OSTI)

    Glaser, S.D.; Dudley, J.W. II; Shlyapobersky, J.

    1999-07-01

    An automated laboratory hydraulic fracture experiment has been assembled to determine what rock and treatment parameters are crucial to improving the efficiency and effectiveness of field hydraulic fractures. To this end a large (460 mm cubic sample) polyaxial cell, with servo-controlled X,Y,Z, pore pressure, crack-mouth-opening-displacement, and bottom hole pressure, was built. Active imaging with embedded seismic diffraction arrays images the geometry of the fracture. Preliminary tests indicate fracture extent can be imaged to within 5%. Unique embeddible high-fidelity particle velocity AE sensors were designed and calibrated to allow determination of fracture source kinematics.

  19. Edit paper Methods for Large Scale Hydraulic Fracture Monitoring

    E-Print Network [OSTI]

    Ely, Gregory

    2013-01-01

    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...

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

    E-Print Network [OSTI]

    Liu, Yuwei

    2013-01-01

    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 ...

  1. Lower bound on the critical energy for the onset of chaos and the chaotic dynamical aperture of large accelerators

    SciTech Connect (OSTI)

    Guersey, Y. (Department of Natural Sciences, Baruch College of The City University of New York, 17 Lexington Avenue, New York 10010 (United States)); Alhassid, Y. (Center for Theoretical Physics, Sloane Physics Laboratory, Yale University, New Haven, Conneticut 06511 (United States) Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06511 (United States))

    1992-02-15

    A generic nonintegrable Hamiltonian system is characterized by a critical energy above which chaotic motion sets in. A general method of finding a lower bound to this critical energy that does not require a solution of the equations of motion is discussed. Below the critical energy, the motion is regular everywhere on the energy surface and no instabilities can develop. The method is applied to a practical situation encountered in modern large accelerators, where the transverse motion of the particles in an arrangement of quadrupole, sextupole, and octupole magnetic elements may become chaotic. The chaotic dynamical aperture of the beam is calculated as a function of a dimensionless strength parameter. The estimated critical energy is compared with that obtained from detailed studies of the Poincare sections of the above system at various energies.

  2. Three dimensional geologic modeling of a fractured reservoir, Saudi Arabia

    SciTech Connect (OSTI)

    Luthy, S.T.; Grover, G.A. [Saudi Aramco, Dhahran (Saudi Arabia)

    1995-11-01

    A geological assessment of a large carbonate reservoir in Saudi Arabia shows that it is a Type 2 fractured reservoir in which fractures provide the essential permeability. Intercrystalline microporosity, found within the basinally deposited mudstones and wackestones, is the dominant porosity type. Near-vertical, east-west-oriented extension fractures are preferentially localized in low-to-moderate porosities associated with stylolites. Porosity/fracture density relationships, combined with the results of structural curvature mapping, yielded a 3-dimensional model of fracture density. Fracture permeability and fracture porosity distributions were generated by integrating fracture density modeling results with average fracture aperture information derived from well test data. Dramatic differences exist between matrix- and fracture-related porosity, permeability models that help explain observed production behavior within the field. These models are being used by reservoir and simulation engineers for daily reservoir management, history matching, and long-term development drilling planning.

  3. Concentration of Starlight from Large Apertures into a Single Spatial Mode for LongBaseline Interferometry

    E-Print Network [OSTI]

    Meisner, Jeff

    of a natural guide star adaptive optics system designed for the purpose of concentrating light from a large with the results of simulations of such a system. It is con­ cluded that an adaptive optics system contribute shot noise. Not only will the signal­to­ noise ratio not be augmented by the additional light

  4. LUPUS I observations from the 2010 flight of the Balloon-borne large aperture submillimeter telescope for polarimetry

    SciTech Connect (OSTI)

    Matthews, Tristan G.; Chapman, Nicholas L.; Novak, Giles [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Ade, Peter A. R.; Hargrave, Peter C.; Nutter, David [Cardiff University, School of Physics and Astronomy, Queens Buildings, The Parade, Cardiff, CF24 3AA (United Kingdom); Angilè, Francesco E.; Devlin, Mark J.; Klein, Jeffrey [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Benton, Steven J.; Fissel, Laura M.; Gandilo, Natalie N.; Netterfield, Calvin B. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street Toronto, ON M5S 3H4 (Canada); Chapin, Edward L. [XMM SOC, ESAC, Apartado 78, E-28691 Villanueva de la Cañada, Madrid (Spain); Fukui, Yasuo [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Gundersen, Joshua O. [Department of Physics, University of Miami, 1320 Campo Sano Drive, Coral Gables, FL 33146 (United States); Korotkov, Andrei L. [Department of Physics, Brown University, 182 Hope Street, Providence, RI 02912 (United States); Moncelsi, Lorenzo; Mroczkowski, Tony K. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Olmi, Luca [University of Puerto Rico, Rio Piedras Campus, Physics Department, Box 23343, UPR station, San Juan (Puerto Rico); and others

    2014-04-01

    The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) was created by adding polarimetric capability to the BLAST experiment that was flown in 2003, 2005, and 2006. BLASTPol inherited BLAST's 1.8 m primary and its Herschel/SPIRE heritage focal plane that allows simultaneous observation at 250, 350, and 500 ?m. We flew BLASTPol in 2010 and again in 2012. Both were long duration Antarctic flights. Here we present polarimetry of the nearby filamentary dark cloud Lupus I obtained during the 2010 flight. Despite limitations imposed by the effects of a damaged optical component, we were able to clearly detect submillimeter polarization on degree scales. We compare the resulting BLASTPol magnetic field map with a similar map made via optical polarimetry. (The optical data were published in 1998 by J. Rizzo and collaborators.) The two maps partially overlap and are reasonably consistent with one another. We compare these magnetic field maps to the orientations of filaments in Lupus I, and we find that the dominant filament in the cloud is approximately perpendicular to the large-scale field, while secondary filaments appear to run parallel to the magnetic fields in their vicinities. This is similar to what is observed in Serpens South via near-IR polarimetry, and consistent with what is seen in MHD simulations by F. Nakamura and Z. Li.

  5. OVERBURDEN PRESSURE AFFECTS FRACTURE APERTURE

    E-Print Network [OSTI]

    Schechter, David S.

    , numerical modeling/reservoir simulation, well testing and geomechanics. Prior to joining TAMU he worked

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

    E-Print Network [OSTI]

    Maxime Lefranc; Elisabeth Bouchaud

    2015-01-06

    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.

  7. Fracture compliance estimation using borehole tube waves

    E-Print Network [OSTI]

    Bakku, Sudhish Kumar

    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 ...

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

    SciTech Connect (OSTI)

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

    2011-01-01

    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.

  9. A new friction factor correlation for laminar, single-phase flows through rock fractures

    SciTech Connect (OSTI)

    Nazridoust, K. (Clarkson Univ., Potsdam, NY); Ahmadi, G. (Clarkson Univ., Potsdam, NY); Smith, D.H.

    2006-09-30

    Single-phase flow through fractured media occurs in various situations, such as transport of dissolved contaminants through geological strata, sequestration of carbon dioxide in depleted gas reservoirs, and in primary oil recovery. In the present study, fluid flows through a rock fracture were simulated. The fracture geometry was obtained from the CT scans of a rock fracture produced by the Brazilian method in a sandstone sample. A post-processing code using a CAD package was developed and used to generate the three-dimensional fracture from the CT scan data. Several sections along the fracture were considered and the GambitTM code was used to generate unstructured grids for flow simulations. FLUENTTM was used to analyze the flow conditions through the fracture section for different flow rates. Because of the small aperture of the fractures, the gravitational effects could be neglected. It was confirmed that the pressure drop was dominated by the smallest aperture passages of the fracture. The accuracy of parallel plate models for estimating the pressure drops through fractures was studied. It was shown that the parallel plate flow model with the use of an appropriate effective fracture aperture and inclusion of the tortuosity factor could provide reasonable estimates for pressure drops in the fracture. On the basis of the CFD simulation data, a new expression for the friction factor for flows through fractures was developed. The new model predictions were compared with the simulation results and favorable agreement was found. It was shown that when the length of the fracture and the mean and standard deviation of the fracture are known, the pressure loss as a function of the flow rate could be estimated. These findings may prove useful for design of lab experiments, computational studied of flows through real rock fractures, or inclusions in simulators for large-scale flows in highly fractured rocks.

  10. Evaluating GPR polarization effects for imaging fracture channeling and estimating fracture properties

    E-Print Network [OSTI]

    Perll, Chris

    2013-12-31

    . To understand how the polarization of radar waves affects imaging of channelized flow in a horizontal fracture, i) a series of numerical forward models was created with varying fracture aperture, channel orientation, and varying fracture water electrical...

  11. Microbranching in mode-I fracture using large scale simulations of amorphous and perturbed lattice models

    E-Print Network [OSTI]

    Shay I. Heizler; David A. Kessler

    2015-05-18

    We study the high-velocity regime mode-I fracture instability when small microbranches start to appear near the main crack, using large scale simulations. Some of the features of those microbranches have been reproduced qualitatively in smaller scale studies (using ${\\cal O}(10^4)$ atoms) on both a model of an amorphous materials (via the continuous random network model) and using perturbed lattice models. In this study, larger scale simulations (${\\cal O}(10^6)$ atoms) were performed using multi-threading computing on a GPU device, in order to achieve more physically realistic results. First, we find that the microbranching pattern appears to be converging with the lattice width. Second, the simulations reproduce the growth of the size of a microbranch as a function of the crack velocity, as well as the increase of the amplitude of the derivative of the electrical resistance RMS with respect to the time as a function of the crack velocity. In addition, the simulations yield the correct branching angle of the microbranches, and the power law governing the shape of the microbranches seems to be lower than one, so that the side cracks turn over in the direction of propagation of the main crack as seen in experiment.

  12. The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) 2005: A 4 sq. deg Galactic Plane Survey in Vulpecula (l=59)

    E-Print Network [OSTI]

    E. L. Chapin; P. A. R. Ade; J. J. Bock; C. Brunt; M. J. Devlin; S. Dicker; M. Griffin; J. O. Gundersen; M. Halpern; P. C. Hargrave; D. H. Hughes; J. Klein; G. Marsden; P. G. Martin; P. Mauskopf; C. B. Netterfield; L. Olmi; E. Pascale; G. Patanchon; M. Rex; D. Scott; C. Semisch; M. D. P. Truch; C. Tucker; G. S. Tucker; M. P. Viero; D. V. Wiebe

    2007-11-21

    We present the first results from a new 250, 350, and 500 micron Galactic Plane survey taken with the Balloon-borne Large-Aperture Submillimeter Telescope (BLAST) in 2005. This survey's primary goal is to identify and characterize high-mass proto-stellar objects (HMPOs). The region studied here covers 4 sq. deg near the open cluster NGC 6823 in the constellation Vulpecula (l=59). We find 60 compact sources (0) velocities combined with a variety of other velocity and morphological data in the literature. In total, 49 sources are associated with a molecular cloud complex encompassing NGC 6823 (distance ~2.3kpc), 10 objects with the Perseus Arm (~8.5kpc) and one object is probably in the outer Galaxy (~14kpc). Near NGC 6823, the inferred luminosities and masses of BLAST sources span ~40-10^4 L_\\odot, and ~15-700 M_\\odot, respectively. The mass spectrum is compatible with molecular gas masses in other high-mass star forming regions. Several luminous sources appear to be Ultra Compact HII regions powered by early B stars. However, many of the objects are cool, massive gravitationally-bound clumps with no obvious internal radiation from a protostar, and hence excellent HMPO candidates.

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

    SciTech Connect (OSTI)

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

    2002-04-24

    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.

  14. Proceedings of the Joint IAEA/CSNI Specialists` Meeting on Fracture Mechanics Verification by Large-Scale Testing held at Pollard Auditorium, Oak Ridge, Tennessee

    SciTech Connect (OSTI)

    Pugh, C.E.; Bass, B.R.; Keeney, J.A.

    1993-10-01

    This report contains 40 papers that were presented at the Joint IAEA/CSNI Specialists` Meeting Fracture Mechanics Verification by Large-Scale Testing held at the Pollard Auditorium, Oak Ridge, Tennessee, during the week of October 26--29, 1992. The papers are printed in the order of their presentation in each session and describe recent large-scale fracture (brittle and/or ductile) experiments, analyses of these experiments, and comparisons between predictions and experimental results. The goal of the meeting was to allow international experts to examine the fracture behavior of various materials and structures under conditions relevant to nuclear reactor components and operating environments. The emphasis was on the ability of various fracture models and analysis methods to predict the wide range of experimental data now available. The individual papers have been cataloged separately.

  15. Geomechanics of hydraulic fracturing microseismicity

    E-Print Network [OSTI]

    Ze'ev, Reches

    Geomechanics of hydraulic fracturing microseismicity: Part 2. Stress state determination Seth Busetti and Ze'ev Reches ABSTRACT We investigate the hydraulic fracturing process by analysis, stress shadowing adjacent to large parent hydraulic fractures, and crack tip stress perturbations. Data

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

    SciTech Connect (OSTI)

    Detwiler, Russell

    2014-06-30

    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.

  17. Rotating Aperture System

    SciTech Connect (OSTI)

    Rusnak, Brian; Hall, James M.; Shen, Stewart; Wood, Richard L.

    2005-01-18

    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.

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

    E-Print Network [OSTI]

    crack growth, and some implications for rock engineering R.A. Schultz* Geomechanics-Rock Fracture Group

  19. Investigating the changes in matrix and fracture properties and fluid flow under different stress-state conditions 

    E-Print Network [OSTI]

    Muralidharan, Vivek

    2004-11-15

    The fracture aperture and fracture permeability are usually considered to remain the same during the production life of a naturally fractured reservoir, regardless of the degree of depletion; but reservoirs experience different stress state...

  20. Variable-aperture screen

    DOE Patents [OSTI]

    Savage, G.M.

    1991-10-29

    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.

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

    SciTech Connect (OSTI)

    Ahmad Ghassemi

    2009-10-01

    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.

  2. Geomechanical properties of tight, low-porosity reser-voirs are largely governed by natural fracture networks.

    E-Print Network [OSTI]

    Tsvankin, Ilya

    inversion methods that operate with both 3D wide- azimuth surface data and VSP (vertical seismic profiling of surface seismic data. However, the corre- lation between areas of high fracture density and fault locations is not always straightforward. Therefore, fracture characterization increasingly relies on seismic

  3. Confocal coded aperture imaging

    DOE Patents [OSTI]

    Tobin, Jr., Kenneth William (Harriman, TN); Thomas, Jr., Clarence E. (Knoxville, TN)

    2001-01-01

    A method for imaging a target volume comprises the steps of: radiating a small bandwidth of energy toward the target volume; focusing the small bandwidth of energy into a beam; moving the target volume through a plurality of positions within the focused beam; collecting a beam of energy scattered from the target volume with a non-diffractive confocal coded aperture; generating a shadow image of said aperture from every point source of radiation in the target volume; and, reconstructing the shadow image into a 3-dimensional image of the every point source by mathematically correlating the shadow image with a digital or analog version of the coded aperture. The method can comprise the step of collecting the beam of energy scattered from the target volume with a Fresnel zone plate.

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

    E-Print Network [OSTI]

    Ayyildiz, Muhammed

    2012-08-28

    Characterization of fractures in an arkosic sandstone from the western damage zone of the San Andreas Fault (SAF) at San Andreas Fault Observatory at Depth (SAFOD) was used to better understand the origin of damage and to determine the scale...

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

    E-Print Network [OSTI]

    Horn, Berthold K.P.

    - strument [2] that makes a map of the radiation field as it trav- erses a region. The pixel size of the map in searching for radiation sources. The instrument was constructed to verify that weak point sources can sufficient radiation can reach a large gamma-ray detec- tor from a small source to make detection possible

  6. Aperture center energy showcase

    SciTech Connect (OSTI)

    Torres, J. J.

    2012-03-01

    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.

  7. Project Profile: Improved Large Aperture Collector Manufacturing |

    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 RankADVANCED MANUFACTURINGEnergy Bills andOrderNATIONALofDefine ReviewImpactDepartment ofBaseloadDepartment

  8. Sparse aperture endoscope

    DOE Patents [OSTI]

    Fitch, Joseph P. (Livermore, CA)

    1999-07-06

    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.

  9. Sparse aperture endoscope

    DOE Patents [OSTI]

    Fitch, J.P.

    1999-07-06

    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.

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

    SciTech Connect (OSTI)

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

    2013-08-01

    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.

  11. Cubic law with aperture-length correlation: implications for network scale fluid flow

    E-Print Network [OSTI]

    unit width normal to the direction of flow is proportional to the cubed aperture between the plates, fractures govern the hydraulic properties of these rocks (e.g. Bear et al. 1993; National Research Council; Brown 1987; Taylor et al. 1999; Rivard and Delay 2004). So far, however, both fields have mainly been

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

    SciTech Connect (OSTI)

    Lance Prothro

    2008-03-01

    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.

  13. Simulation of naturally fractured reservoirs

    SciTech Connect (OSTI)

    Saidi, A.M.

    1983-11-01

    A three-dimensional, three-phase reservoir simulator was developed to study the behavior of fully or partially fractured reservoirs. It is also demonstrated, that when a fractured reservoir is subject to a relatively large rate of pressure drop and/or it composed of relatively large blocks, the pseudo steady-state pressure concept gives large errors as compared with transient fromulation. In addition, when gravity drainage and imbibitum processes, which is the most important mechanism in the fractured reservoirs, are represented by a ''lumped parameter'' even larger errors can be produced in exchange flow between matrix and fractures. For these reasons, the matrix blocks are gridded and the transfer between matrix and fractures are calculated using pressure and diffusion transient concept. In this way the gravity drainage is also calculated accurately. As the matrix-fracture exchange flow depends on the location of each matrix grid relative to the GOC and/or WOC in fracture, the exchange flow equation are derived and given for each possible case. The differential equation describing the flow of water, oil, and gas within the matrix and fracture system, each of which may contain six unknowns, are presented. The two sets of equations are solved implicitly for pressure water, and gas stauration in both matrix and fractures. The first twenty two years of the history of Haft Kel field was successfully matched with this model and the results are included.

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

    E-Print Network [OSTI]

    Peirce, Anthony

    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

  15. WFPC2 aperture photometry and PSF modelling

    E-Print Network [OSTI]

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

    1995-03-22

    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.

  16. Aperture-Tolerant, Chemical-Based Methods to Reduce Channeling

    SciTech Connect (OSTI)

    Randall S. Seright

    2007-09-30

    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.

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

    SciTech Connect (OSTI)

    Huang, Hai; Plummer, Mitchell; Podgorney, Robert

    2013-02-01

    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.

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

    E-Print Network [OSTI]

    Marcadet, Stephane (Stephane Jean Marie)

    2012-01-01

    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 ...

  19. GPR Method for the Detection and Characterization of Fractures and Karst Features: Polarimetry, Attribute Extraction, Inverse Modeling and Data Mining Techniques 

    E-Print Network [OSTI]

    Sassen, Douglas Spencer

    2011-02-22

    ., 2006) There is still significant scope for development of methods that enhance the detection of fractures by utilizing the vectorial nature of GPR waves and allow for quantitative descriptions of the fracture aperture and fill materials through... on the aperture, fill and orientation of the fracture. As the electromagnetic waves of GPR are vectorial in nature, features exhibiting strong directionality can change the state of polarization of the incident field. GPR methods that focus on changes...

  20. Microseismic Tracer Particles for Hydraulic Fracturing

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

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

  1. Statistical analysis of liquid seepage in partially saturated heterogeneous fracture systems

    SciTech Connect (OSTI)

    Liou, T.S.

    1999-12-01

    Field evidence suggests that water flow in unsaturated fracture systems may occur along fast preferential flow paths. However, conventional macroscale continuum approaches generally predict the downward migration of water as a spatially uniform wetting front subjected to strong inhibition into the partially saturated rock matrix. One possible cause of this discrepancy may be the spatially random geometry of the fracture surfaces, and hence, the irregular fracture aperture. Therefore, a numerical model was developed in this study to investigate the effects of geometric features of natural rock fractures on liquid seepage and solute transport in 2-D planar fractures under isothermal, partially saturated conditions. The fractures were conceptualized as 2-D heterogeneous porous media that are characterized by their spatially correlated permeability fields. A statistical simulator, which uses a simulated annealing (SA) algorithm, was employed to generate synthetic permeability fields. Hypothesized geometric features that are expected to be relevant for seepage behavior, such as spatially correlated asperity contacts, were considered in the SA algorithm. Most importantly, a new perturbation mechanism for SA was developed in order to consider specifically the spatial correlation near conditioning asperity contacts. Numerical simulations of fluid flow and solute transport were then performed in these synthetic fractures by the flow simulator TOUGH2, assuming that the effects of matrix permeability, gas phase pressure, capillary/permeability hysteresis, and molecular diffusion can be neglected. Results of flow simulation showed that liquid seepage in partially saturated fractures is characterized by localized preferential flow, along with bypassing, funneling, and localized ponding. Seepage pattern is dominated by the fraction of asperity contracts, and their shape, size, and spatial correlation. However, the correlation structure of permeability field is less important than the spatial correlation of asperity contacts. A faster breakthrough was observed in fractures subjected to higher normal stress, accompanied with a nonlinearly decreasing trend of the effective permeability. Interestingly, seepage dispersion is generally higher in fractures with intermediate fraction of asperity contacts; but it is lower for small or large fractions of asperity contacts. However, it may become higher if the ponding becomes significant. Transport simulations indicate that tracers bypass dead-end pores and travel along flow paths that have less flow resistance. Accordingly, tracer breakthrough curves generally show more spreading than breakthrough curves for water. Further analyses suggest that the log-normal time model generally fails to fit the breakthrough curves for water, but it is a good approximation for breakthrough curves for the tracer.

  2. Accelerator dynamics and beam aperture

    SciTech Connect (OSTI)

    Parsa, Z.

    1986-10-01

    We present an analytical method for analyzing accelerator dynamics, including higher order effects of multipoles on the beam. This formalism provides a faster alternative to particle tracking. Simplectic expressions for the emittance and phase describing the dynamical behavior of a particle in a circular accelerator are derived using second order perturbation theory (in the presence of nonlinear elements, e.g., sextupoles, octupoles). These expressions are successfully used to calculate the emittance growth, smear and linear aperture. Our findings compare well with results obtained from tracking programs. In addition perturbation to betatron tune; resonance strengths; stop bandwidth; fixed points; island width; and Chirikov criteria are calculated.

  3. Development of Reservoir Characterization Techniques and Production Models for Exploiting Naturally Fractured Reservoirs

    SciTech Connect (OSTI)

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

    2002-10-08

    During this reporting period, research was continued on characterizing and modeling the behavior of naturally fractured reservoir systems. This report proposed a model to relate the seismic response to production data to determine crack spacing and aperture, provided details of tests of proposed models to obtain fracture properties from conventional well logs with actual field data, and verification of the naturally fractured reservoir simulator developed in this project.

  4. Fracture Characteristics in a Disposal Pit on Mesita del Buey, Los Alamos National Laboratory

    SciTech Connect (OSTI)

    David T. Vaniman; Steven L. Reneau

    1998-12-01

    The characteristics of fractures in unit 2 of the Tshirege Member of the Bandelier Tuff were documented in Pit 39, a newly excavated 13.7 m deep disposal pit at Material Disposal Area G on Mesita del Buey. The average spacing between fractures is about 1.0 to 1.3 m, the average fracture aperture is about 3 to 5 mm, and the average fracture dip is about 76o to 77o. Fracture spacing and dip in Pit 39 are generally consistent with that reported from other fracture studies on the Pajarito Plateau, although the fracture apertures in Pit 39 are less than reported elsewhere. Measured fracture orientations are strongly affected by biases imparted by the orientations of the pit walls, which, combined with a small data set, make identification of potential preferred orientations dlfflcult. The most prominent fracture orientations observed in Pit 39, about E-W and N20E, are often not well represented elsewhere on the Pajarito Plateau. Fracture fills contain smectite to about 3 m depth, and calcite and opal may occur at all depths, principally associated with roots or root fossils (rhizoliths). Roots of pifion pine extend in fractures to the bottom of the pit along the north side, perhaps indicating a zone of preferred infiltration of water. Finely powdered tuff with clay-sized particles occurs within a number of fractures and may record abrasive disaggregation associated with small amounts of displacement on minor local faults.

  5. Numerical Investigation of Interaction Between Hydraulic Fractures and Natural Fractures 

    E-Print Network [OSTI]

    Xue, Wenxu

    2011-02-22

    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...

  6. Hydrothermal coupling in a rough fracture

    E-Print Network [OSTI]

    Neuville, A; Schmittbuhl, J; Neuville, Am\\'{e}lie; Toussaint, Renaud; Schmittbuhl, Jean

    2006-01-01

    Heat exchange during laminar flow is studied at the fracture scale on the basis of the Stokes equation. We used a synthetic aperture model (a self-affine model) that has been shown to be a realistic geometrical description of the fracture morphology. We developed a numerical modelling using a finite difference scheme of the hydrodynamic flow and its coupling with an advection/conduction description of the fluid heat. As a first step, temperature within the surrounding rock is supposed to be constant. Influence of the fracture roughness on the heat flux through the wall, is estimated and a thermalization length is shown to emerge. Implications for the Soultz-sous-For\\^{e}ts geothermal project are discussed.

  7. 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]

    Cerveny, Vlastislav

    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

  8. Laboratory testing of cement grouting of fractures in welded tuff

    SciTech Connect (OSTI)

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

    1991-03-01

    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.

  9. Transmission enhancement through deep subwavelength apertures using connected split

    E-Print Network [OSTI]

    Transmission enhancement through deep subwavelength apertures using connected split ring resonators transmission enhancement factors through a subwavelength aperture at microwave frequencies by placing connected transmission through a deep subwavelength aperture with an electrical size of /31×/12 (width × length

  10. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousand CubicResourcelogo and mastheadLakeLanguage of a fly provesLarge

  11. Selection of fracture fluid for stimulating tight gas reservoirs 

    E-Print Network [OSTI]

    Malpani, Rajgopal Vijaykumar

    2007-04-25

    Essentially all producing wells drilled in tight gas sands and shales are stimulated using hydraulic fracture treatments. The development of optimal fracturing procedures, therefore, has a large impact on the long-term economic viability...

  12. Fracture-permeability behavior of shale

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

    Carey, J. William; Lei, Zhou; Rougier, Esteban; Mori, Hiroko; Viswanathan, Hari

    2015-05-08

    The fracture-permeability behavior of Utica shale, an important play for shale gas and oil, was investigated using a triaxial coreflood device and X-ray tomography in combination with finite-discrete element modeling (FDEM). Fractures generated in both compression and in a direct-shear configuration allowed permeability to be measured across the faces of cylindrical core. Shale with bedding planes perpendicular to direct-shear loading developed complex fracture networks and peak permeability of 30 mD that fell to 5 mD under hydrostatic conditions. Shale with bedding planes parallel to shear loading developed simple fractures with peak permeability as high as 900 mD. In addition tomore »the large anisotropy in fracture permeability, the amount of deformation required to initiate fractures was greater for perpendicular layering (about 1% versus 0.4%), and in both cases activation of existing fractures are more likely sources of permeability in shale gas plays or damaged caprock in CO? sequestration because of the significant deformation required to form new fracture networks. FDEM numerical simulations were able to replicate the main features of the fracturing processes while showing the importance of fluid penetration into fractures as well as layering in determining fracture patterns.« less

  13. Fracture-permeability behavior of shale

    SciTech Connect (OSTI)

    Carey, J. William; Lei, Zhou; Rougier, Esteban; Mori, Hiroko; Viswanathan, Hari

    2015-05-08

    The fracture-permeability behavior of Utica shale, an important play for shale gas and oil, was investigated using a triaxial coreflood device and X-ray tomography in combination with finite-discrete element modeling (FDEM). Fractures generated in both compression and in a direct-shear configuration allowed permeability to be measured across the faces of cylindrical core. Shale with bedding planes perpendicular to direct-shear loading developed complex fracture networks and peak permeability of 30 mD that fell to 5 mD under hydrostatic conditions. Shale with bedding planes parallel to shear loading developed simple fractures with peak permeability as high as 900 mD. In addition to the large anisotropy in fracture permeability, the amount of deformation required to initiate fractures was greater for perpendicular layering (about 1% versus 0.4%), and in both cases activation of existing fractures are more likely sources of permeability in shale gas plays or damaged caprock in CO? sequestration because of the significant deformation required to form new fracture networks. FDEM numerical simulations were able to replicate the main features of the fracturing processes while showing the importance of fluid penetration into fractures as well as layering in determining fracture patterns.

  14. Light Transmission through Sub-Wavelength Apertures

    E-Print Network [OSTI]

    Visser, Taco D.

    Light Transmission through Sub-Wavelength Apertures #12;#12;VRIJE UNIVERSITEIT Light Transmission Transmission through a Single Sub-wavelength Slit 59 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 3.2 The configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 3.3 Transmission

  15. Multi-channel coded-aperture photography

    E-Print Network [OSTI]

    Baek, Jongmin

    2008-01-01

    This thesis describes the multi-channel coded-aperture photography, a modified camera system that can extract an all-focus image of the scene along with a depth estimate over the scene. The modification consists of inserting ...

  16. Fracture Properties From Seismic Scattering

    E-Print Network [OSTI]

    Burns, Daniel R.

    2007-01-01

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

  17. The LASS (Larger Aperture Superconducting Solenoid) spectrometer

    SciTech Connect (OSTI)

    Aston, D.; Awaji, N.; Barnett, B.; Bienz, T.; Bierce, R.; Bird, F.; Bird, L.; Blockus, D.; Carnegie, R.K.; Chien, C.Y.

    1986-04-01

    LASS is the acronym for the Large Aperture Superconducting Solenoid spectrometer which is located in an rf-separated hadron beam at the Stanford Linear Accelerator Center. This spectrometer was constructed in order to perform high statistics studies of multiparticle final states produced in hadron reactions. Such reactions are frequently characterized by events having complicated topologies and/or relatively high particle multiplicity. Their detailed study requires a spectrometer which can provide good resolution in momentum and position over almost the entire solid angle subtended by the production point. In addition, good final state particle identification must be available so that separation of the many kinematically-overlapping final states can be achieved. Precise analyses of the individual reaction channels require high statistics, so that the spectrometer must be capable of high data-taking rates in order that such samples can be acquired in a reasonable running time. Finally, the spectrometer must be complemented by a sophisticated off-line analysis package which efficiently finds tracks, recognizes and fits event topologies and correctly associates the available particle identification information. This, together with complicated programs which perform specific analysis tasks such as partial wave analysis, requires a great deal of software effort allied to a very large computing capacity. This paper describes the construction and performance of the LASS spectrometer, which is an attempt to realize the features just discussed. The configuration of the spectrometer corresponds to the data-taking on K and K interactions in hydrogen at 11 GeV/c which took place in 1981 and 1982. This constitutes a major upgrade of the configuration used to acquire lower statistics data on 11 GeV/c K p interactions during 1977 and 1978, which is also described briefly.

  18. Discrete Fracture Reservoir Simulation

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

    Discrete Fracture Reservoir Simulation Shale Gas Flow Simulation Shale Gas Flow Simulation FRACGENNFFLOW, fractured reservoir modeling software developed by NETL's Geological and...

  19. Capillary fracture of soft gels

    E-Print Network [OSTI]

    Joshua B. Bostwick; Karen E. Daniels

    2013-10-16

    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 important factor in the fracture process, as it can help mitigate large surface tractions; this finding is confirmed with experiments. We then develop a model for crack propagation by considering the transport of an inviscid fluid into the fracture tip of an incompressible material, and find that a simple energy-conservation argument can explain the observed material-independent power law. We compare predictions for both linear elastic and neo-Hookean solids finding that the latter better explains the observed exponent.

  20. Laboratory studies of radionuclide transport in fractured Climax granite

    SciTech Connect (OSTI)

    Failor, R.; Isherwood, D.; Raber, E.; Vandergraaf, T.

    1982-06-01

    This report documents our laboratory studies of radionuclide transport in fractured granite cores. To simulate natural conditions, our laboratory studies used naturally fractured cores and natural ground water from the Climax Granite Stock at the Nevada Test Site. For comparison, additional tests used artificially fractured granite cores or distilled water. Relative to the flow of tritiated water, {sup 85}Sr and /sup 95m/Tc showed little or no retardation, whereas {sup 137}Cs was retarded. After the transport runs the cores retained varying amounts of the injected radionuclides along the fracture. Autoradiography revealed some correlation between sorption and the fracture fill material. Strontium and cesium retention increased when the change was made from natural ground water to distilled water. Artificial fractures retained less {sup 137}Cs than most natural fractures. Estimated fracture apertures from 18 to 60 {mu}m and hydraulic conductivities from 1.7 to 26 x 10{sup -3} m/s were calculated from the core measurements.

  1. Identifying Fracture Types and Relative Ages Using Fluid Inclusion Stratigraphy

    SciTech Connect (OSTI)

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

    2008-06-30

    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.

  2. Spatial statistics for predicting flow through a rock fracture

    SciTech Connect (OSTI)

    Coakley, K.J.

    1989-03-01

    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.

  3. Comparative study of the inial spikes of SGR giant flares in 1998 and 2004 observed with GEOTAIL: Do magnetospheric instabilities trigger large scale fracturing of magnetar's crust?

    E-Print Network [OSTI]

    Y. T. Tanaka; T. Terasawa; N. Kawai; A. Yoshida; I. Yoshikawa; Y. Saito; T. Takashima; T. Mukai

    2007-06-21

    We present the unsaturated peak profile of SGR 1900+14 giant flare on 1998 August 27. This was obtained by particle counters of the Low Energy Particle instrument onboard the GEOTAIL spacecraft. The observed peak profile revealed four characteristic structures: initial steep rise, intermediate rise to the peak, exponential decay and small hump in the decay phase. From this light curve, we found that the isotropic peak luminosity was $2.3\\times10^{46}$ erg s$^{-1}$ and the total energy was $4.3 \\times 10^{44}$ erg s$^{-1}$ ($E\\gtrsim$ 50 keV), assuming that the distance to SGR 1900+14 is 15 kpc and that the spectrum is optically thin thermal bremsstrahlung with $kT =$ 240 keV. These are consistent with the previously reported lower limits derived from Ulysses and Konus-Wind observations. A comparative study of the initial spikes of SGR 1900+14 giant flare in 1998 and SGR 1806-20 in 2004 is also presented. The timescale of the initial steep rise shows the magnetospheric origin, while the timescale of the intermediate rise to the peak indicates that it originates from the crustal fracturing. Finally, we argue that the four structures and their corresponding timescales provide a clue to identify extragalactic SGR giant flares among short GRBs.

  4. Geomechanics of hydraulic fracturing microseismicity

    E-Print Network [OSTI]

    Ze'ev, Reches

    Geomechanics of hydraulic fracturing microseismicity: Part 1. Shear, hybrid, and tensile events of hydraulic- fracturing-induced microseismicity. Microseismic events are commonly used to discern stimulation patterns and hydraulic fracture evolution; however, techniques beyond fracture mapping are required

  5. Subsurface fracture mapping from geothermal wellbores. Final report

    SciTech Connect (OSTI)

    Hartenbaum, B.A.; Rawson, G.

    1983-08-01

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

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

    E-Print Network [OSTI]

    Verde Salas, Alexander José

    2014-04-28

    to injection – Case 3. ......... 89 6.4. Fluid injection and production in large-scale poroelastic shales – Case 4. ........... 92 7. CONCLUSIONS AND RECOMMENDATIONS ....................................................... 99 7.1. Conclusions...). The displacement discontinuity, Di, is defined as the difference in displacement between the two sides of the segment as: ? ? ? ? snixuxuD iii ,0,0, 11 ??? ?? (2-1) The fundamental solutions provide expressions to compute the induced stresses (?xx, ?yy...

  7. Dual aperture dipole magnet with second harmonic component

    DOE Patents [OSTI]

    Praeg, W.F.

    1983-08-31

    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.

  8. Dual aperture dipole magnet with second harmonic component

    DOE Patents [OSTI]

    Praeg, Walter F. (Palos Park, IL)

    1985-01-01

    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.

  9. High velocity impact fracture

    E-Print Network [OSTI]

    Teng, Xiaoqing

    2005-01-01

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

  10. Off-momentum dynamic aperture for lattices in the RHIC heavy ion runs

    SciTech Connect (OSTI)

    Luo Y.; Bai, M.; Blaskiewicz, M.; Gu, X.; Fischer, W.; Marusic, A.; Roser, T.; Tepikian, S.; Zhang, S.

    2012-05-20

    To reduce transverse emittance growth rates from intrabeam scattering in the RHIC heavy ion runs, a lattice with an increased phase advance in the arc FODO cells was adopted in 2008-2011. During these runs, a large beam loss due to limited off-momentum dynamic aperture was observed during longitudinal RF re-bucketing and with transverse cooling. Based on the beam loss observations in the previous ion runs and the calculated off-momentum apertures, we decided to adopt the lattice used before 2008 for the 2012 U-U and Cu-Au runs. The observed beam decay and the measured momentum aperture in the 2012 U-U run are presented.

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

    E-Print Network [OSTI]

    Forbis, Robert E.

    2014-01-01

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

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

    E-Print Network [OSTI]

    Forbis, Robert E.

    2014-01-01

    History of Hydraulic Fracturing’s Expansion Across The WestHistory of Hydraulic Fracturing’s Expansion Across the Westuse of the hydraulic fracturing development process. First,

  13. 3-D description of fracture surfaces and stress-sensitivity analysis for naturally fractured reservoirs

    SciTech Connect (OSTI)

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

    1997-08-01

    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.

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

    SciTech Connect (OSTI)

    David S. Schechter

    2003-10-01

    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.

  15. Self-potential observations during hydraulic fracturing

    E-Print Network [OSTI]

    Moore, Jeffrey R.; Glaser, Steven D.

    2008-01-01

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

  16. Dual-sided coded-aperture imager

    DOE Patents [OSTI]

    Ziock, Klaus-Peter (Clinton, TN)

    2009-09-22

    In a vehicle, a single detector plane simultaneously measures radiation coming through two coded-aperture masks, one on either side of the detector. To determine which side of the vehicle a source is, the two shadow masks are inverses of each other, i.e., one is a mask and the other is the anti-mask. All of the data that is collected is processed through two versions of an image reconstruction algorithm. One treats the data as if it were obtained through the mask, the other as though the data is obtained through the anti-mask.

  17. Low temperature fracture evaluation of plasticized sulfur paving mixtures 

    E-Print Network [OSTI]

    Mahboub, Kamyar

    1985-01-01

    . Characterize the fracture behavior of sulphlex binders by using the elastic-plastic critical energy release rate, J C. 2. Approximate the fracture toughness of the material, KIC, by the KO parameter and establish a correlation between KO and JIC parameters... concentrations leading to failure of a structural component. The first analysis of fracture behavior of britt! e materials containing sharp flaws was developed by Griffith (16). He considered a very large plate with a sharp crack of length 2a passing...

  18. Simulation of Hydraulic Fractures and their Interactions with Natural Fractures 

    E-Print Network [OSTI]

    Sesetty, Varahanaresh

    2012-10-19

    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...

  19. Fracture characterization from attenuation of Stoneley waves across a fracture

    E-Print Network [OSTI]

    Bakku, Sudhish Kumar

    2012-01-01

    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 ...

  20. Geothermal Ultrasonic Fracture Imager

    Broader source: Energy.gov [DOE]

    Development of a downhole wireline tool to characterize fractures in EGS wells in temperatures up to 300°C and depths up to 10; 000 m.

  1. Dual-porosity reservoir modeling of the fractured Hanifa reservoir, Abqaiq Field, Saudi Arabia

    SciTech Connect (OSTI)

    Luthy, S.T. [Saudi Aramco, Dhahran (Saudi Arabia)

    1995-08-01

    Fractures play a significant role in the transmissibility of the Hanifa reservoir at Abqaiq Field. The Hanifa is a Type 2 fractured reservoir characterized by a finely-crystalline carbonate matrix which contains most of the reservoir storage porosity, and a stylolitic fracture system which provides essential permeability. Integration of borehole imaging data with available open-hole log, core, and well-test data from horizontal and vertical wells allowed for the distribution of fracture parameters, including fracture density, aperture, porosity, and permeability throughout a geocellular model. Analysis of over 5000 fractures showed that changes in lithology, grain size, and/or bed thickness do not correlate with changes in fracture densities. Review of P- and S-wave log data showed that porosity is negatively correlated with fracture density and mechanical rock strength. From these relationships, it was possible to utilize additional wells where porosity log data was available to calculate fracture densities. These wells were used to generate matrix porosity and permeability as well as fracture density attributes in a 12-sequence, 29-layer geocellular model. Fracture permeabilities compare favorably with well-test derived productivity indices. Three-dimensional visualization of model attributes showed that a monotonous and low (<10 md) distribution of matrix- related permeability contrasts sharply with highly variable and relatively high (ER 50 md) permeabilities of the fracture system. Reliability of the geocellular model to predict fracture densities and associated permeabilities has been confirmed by subsequent drilling of high cost horizontal wells, and is being used in reservoir engineering and development drilling planning efforts.

  2. Functionalized apertures for the detection of chemical and biological materials

    DOE Patents [OSTI]

    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)

    2010-12-14

    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.

  3. Inversion of synthetic aperture radar interferograms for sources...

    Open Energy Info (EERE)

    Inversion of synthetic aperture radar interferograms for sources of production-related subsidence at the Dixie Valley geothermal field Jump to: navigation, search OpenEI Reference...

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

    E-Print Network [OSTI]

    Lolon, Elyezer P.

    2006-04-12

    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...

  5. High numerical aperture multilayer Laue lenses

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

    Morgan, Andrew J.; Prasciolu, Mauro; Andrejczuk, Andrzej; Krzywinski, Jacek; Meents, Alke; Pennicard, David; Graafsma, Heinz; Barty, Anton; Bean, Richard J.; Barthelmess, Miriam; et al

    2015-06-01

    The ever-increasing brightness of synchrotron radiation sources demands improved X-ray optics to utilise their capability for imaging and probing biological cells, nanodevices, and functional matter on the nanometer scale with chemical sensitivity. Here we demonstrate focusing a hard X-ray beam to an 8 nm focus using a volume zone plate (also referred to as a wedged multilayer Laue lens). This lens was constructed using a new deposition technique that enabled the independent control of the angle and thickness of diffracting layers to microradian and nanometer precision, respectively. This ensured that the Bragg condition is satisfied at each point along themore »lens, leading to a high numerical aperture that is limited only by its extent. We developed a phase-shifting interferometric method based on ptychography to characterise the lens focus. The precision of the fabrication and characterisation demonstrated here provides the path to efficient X-ray optics for imaging at 1 nm resolution.« less

  6. Very high numerical aperture light transmitting device

    DOE Patents [OSTI]

    Allison, Stephen W. (Knoxville, TN); Boatner, Lynn A. (Oak Ridge, TN); Sales, Brian C. (Knoxville, TN)

    1998-01-01

    A new light-transmitting device using a SCIN glass core and a novel calcium sodium cladding has been developed. The very high index of refraction, radiation hardness, similar solubility for rare earths and similar melt and viscosity characteristics of core and cladding materials makes them attractive for several applications such as high-numerical-aperture optical fibers and specialty lenses. Optical fibers up to 60 m in length have been drawn, and several simple lenses have been designed, ground, and polished. Preliminary results on the ability to directly cast optical components of lead-indium phosphate glass are also discussed as well as the suitability of these glasses as a host medium for rare-earth ion lasers and amplifiers.

  7. Aperture Photometry Uncertainties assuming Priors and Correlated Noise

    E-Print Network [OSTI]

    Masci, Frank

    1 Aperture Photometry Uncertainties assuming Priors and Correlated Noise F. Masci, version 2.0, 10 aperture photometry assuming (i) prior pixel-flux uncertainties are available for the image (e.g., computed photometry is being performed. One way to do this is to compare the uncertainties with the local RMS pixel

  8. Synthetic aperture design for increased SAR image rate

    DOE Patents [OSTI]

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

    2009-03-03

    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.

  9. SU-E-T-10: A Dosimetric Comparison of Copper to Lead-Alloy Apertures for Electron Beam Therapy

    SciTech Connect (OSTI)

    Rusk, B; Hogstrom, K; Gibbons, J; Carver, R [Mary Bird Perkins Cancer Center, Baton Rouge, LA (United States)

    2014-06-01

    Purpose: To evaluate dosimetric differences of copper compared to conventional lead-alloy apertures for electron beam therapy. Methods: Copper apertures were manufactured by .decimal, Inc. and matching lead-alloy, Cerrobend, apertures were constructed for 32 square field sizes (2×2 – 20×20 cm{sup 2}) for five applicator sizes (6×6–25×25 cm{sup 2}). Percent depth-dose and off-axis-dose profiles were measured using an electron diode in water with copper and Cerrobend apertures for a subset of aperture sizes (6×6, 10×10, 25×25 cm{sup 2}) and energies (6, 12, 20 MeV). Dose outputs were measured for all field size-aperture combinations and available energies (6–20 MeV). Measurements were taken at 100 and 110 cm SSDs. Using this data, 2D planar absolute dose distributions were constructed and compared. Passing criteria were ±2% of maximum dose or 1-mm distance-to-agreement for 99% of points. Results: A gamma analysis of the beam dosimetry showed 93 of 96 aperture size, applicator, energy, and SSD combinations passed the 2%/1mm criteria. Failures were found for small field size-large applicator combinations at 20 MeV and 100-cm SSD. Copper apertures showed a decrease in bremsstrahlung production due to copper's lower atomic number compared to Cerrobend (greatest difference was 2.5% at 20 MeV). This effect was most prominent at the highest energies with large amounts of shielding material present (small field size-large applicator). Also, an increase in electrons scattered from the collimator edge of copper compared to Cerrobend resulted in an increased dose at the field edge for copper at shallow depths (greatest increase was 1% at 20 MeV). Conclusion: Apertures for field sizes ?6×6 cm{sup 2} at any energy, or for small fields (?4×4 cm{sup 2}) at energies <20 MeV, showed dosimetric differences less than 2%/1mm for more than 99% of points. All field size-applicator size-energy combinations passed 3%/1mm criteria for 100% of points. Work partially funded by .decimal, Inc. (Sanford, FL)

  10. 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

  11. Computing Neck-Shaft Angle of Femur for X-Ray Fracture Detection

    E-Print Network [OSTI]

    Leow, Wee Kheng

    Computing Neck-Shaft Angle of Femur for X-Ray Fracture Detection Tai Peng Tian1 , Ying Chen1 , Wee and 13% of men suffer from osteoporotic fractures of the bone, particularly the older people. Doctors in the hospitals need to manually inspect a large number of x-ray im- ages to identify the fracture cases

  12. FODO-Supercell Based Compact Ring Design with Tunable Momentum Compaction and Optimized Dynamic Aperture

    SciTech Connect (OSTI)

    Sun, Yipeng; /SLAC

    2012-05-11

    A storage ring with tunable momentum compaction has the advantage in achieving different RMS bunch length with similar RF capacity, which is potentially useful for many applications, such as linear collider damping ring and pre-damping ring where injected beam has a large energy spread and a large transverse emittance. A tunable bunch length also makes the commissioning and fine tuning easier in manipulating the single bunch instabilities. In this paper, a compact ring design based on a supercell is presented, which achieves a tunable momentum compaction while maintaining a large dynamic aperture.

  13. Microfabricated high-bandpass foucault aperture for electron microscopy

    DOE Patents [OSTI]

    Glaeser, Robert; Cambie, Rossana; Jin, Jian

    2014-08-26

    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.

  14. Target Discrimination in Synthetic Aperture Radar (SAR) using Artificial Neural Networks 1 TargetDiscriminationinSyntheticApertureRadar(SAR)

    E-Print Network [OSTI]

    Slatton, Clint

    Target Discrimination in Synthetic Aperture Radar (SAR) using Artificial Neural Networks 1 Target principe@cnel.ufl.edu Abstract: This paper addresses target discrimination in synthetic aperture radar (SAR classification but here the goal is discrimination. We will show that the two applications require different cost

  15. Fracture mechanics: 26. volume

    SciTech Connect (OSTI)

    Reuter, W.G.; Underwood, J.H.; Newman, J.C. Jr.

    1995-12-31

    The original objective of these symposia was to promote technical interchange between researchers from the US and worldwide in the field of fracture. This objective was recently expanded to promote technical interchange between researchers in the field of fatigue and fracture. The symposium began with the Swedlow Memorial Lecture entitled ``Patterns and Perspectives in Applied Fracture Mechanics.`` The remaining 42 papers are divided into the following topical sections: Constraint crack initiation; Constraint crack growth; Weldments; Engineered materials; Subcritical crack growth; Dynamic loading; and Applications. Papers within the scope of the Energy Data Base have been processed separately.

  16. Simulation of naturally fractured reservoirs using empirical transfer function 

    E-Print Network [OSTI]

    Tellapaneni, Prasanna Kumar

    2004-09-30

    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...

  17. Motion Measurement for Synthetic Aperture Radar.

    SciTech Connect (OSTI)

    Doerry, Armin W.

    2015-01-01

    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.

  18. Nonmonotonic fracture behavior of polymer nanocomposites

    E-Print Network [OSTI]

    Janaina G. de Castro; Rojman Zargar; Mehdi Habibi; Samet H. Varol; Sapun H. Parekh; Babak Hosseinkhani; Mokhtar Adda-Bedia; Daniel Bonn

    2015-06-02

    Polymer composite materials are widely used for their exceptional mechanical properties, notably their ability to resist large deformations. Here we examine the failure stress and strain of rubbers reinforced by varying amounts of nano-sized silica particles. We find that small amounts of silica increase the fracture stress and strain, but too much filler makes the material become brittle and consequently fracture happens at small deformations. We thus find that as a function of the amount of filler there is an optimum in the breaking resistance at intermediate filler concentrations. We use a modified Griffith theory to establish a direct relation between the material properties and the fracture behavior that agrees with the experiment.

  19. Self-potential observations during hydraulic fracturing

    E-Print Network [OSTI]

    Moore, J R; Glaser, Steven D

    2007-01-01

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

  20. Self-potential observations during hydraulic fracturing

    E-Print Network [OSTI]

    Moore, Jeffrey R.; Glaser, Steven D.

    2008-01-01

    during hydraulic fracturing of Bunter sandstones, Proc. NearMonitoring during hydraulic fracturing using the TG-2 well,processes in hydraulic fracturing, Quarterly Report for The

  1. Self-potential observations during hydraulic fracturing

    E-Print Network [OSTI]

    Moore, J R; Glaser, Steven D

    2007-01-01

    during hydraulic fracturing of Bunter sandstones, Proc. NearSP response during hydraulic fracturing. Citation: Moore, J.observations during hydraulic fracturing, J. Geophys. Res. ,

  2. Microwave-induced thermoacoustic tomography: reconstruction by synthetic aperture 

    E-Print Network [OSTI]

    Feng, Dazi

    2001-01-01

    We have applied the synthetic-aperture method to linear-scanning microwave-induced thermoacoustic tomography in biological tissues. A non-focused ultrasonic transducer was used to receive thermoacoustic signals, to which the delay-and-sum algorithm...

  3. Multiple Instrument Distributed Aperture Sensor (MIDAS) For Planetary Remote Sensing

    E-Print Network [OSTI]

    Marcus, Philip S.

    Multiple Instrument Distributed Aperture Sensor (MIDAS) For Planetary Remote Sensing Joe Pitman An innovative approach that enables greatly increased return from planetary science remote sensing missions as the primary remote sensing science payload, thereby reducing the cost, resources, complexity, integration

  4. Receiver for solar energy collector having improved aperture aspect

    DOE Patents [OSTI]

    McIntire, William R. (Downers Grove, IL)

    1984-01-01

    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.

  5. Acid Fracture and Fracture Conductivity Study of Field Rock Samples 

    E-Print Network [OSTI]

    Underwood, Jarrod

    2013-11-15

    Acid fracturing is a well stimulation strategy designed to increase the productivity of a producing well. The parameters of acid fracturing and the effects of acid interaction on specific rock samples can be studied experimentally. Acid injection...

  6. Investigation of Created Fracture Geometry through Hydraulic Fracture Treatment Analysis 

    E-Print Network [OSTI]

    Ahmed, Ibraheem 1987-

    2012-11-30

    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...

  7. Fracture Conductivity of the Eagle Ford Shale 

    E-Print Network [OSTI]

    Guzek, James J

    2014-07-25

    Hydraulic fracturing is a well completions technique that induces a network of flow channels in a reservoir. These channels are characterized by fracture conductivity, a measure of how easily a liquid or gas flows through the fracture. Fracture...

  8. Reservoir fracture characterizations from seismic scattered waves

    E-Print Network [OSTI]

    Fang, Xinding

    2012-01-01

    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 ...

  9. Microearthquake Technology for EGS Fracture Characterization...

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

    Microearthquake Technology for EGS Fracture Characterization; 2010 Geothermal Technology Program Peer Review Report Microearthquake Technology for EGS Fracture Characterization;...

  10. Fracture prediction in metal sheets

    E-Print Network [OSTI]

    Lee, Young-Woong

    2005-01-01

    One of the most important failure modes of thin-walled structures is fracture. Fracture is predominantly tensile in nature and, in most part, is operated by the physical mechanisms of void nucleation, growth, and linkage. ...

  11. Fluid Flow Modeling in Fractures

    E-Print Network [OSTI]

    Sarkar, Sudipta

    2004-01-01

    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, ...

  12. Fractured Petroleum Reservoirs

    SciTech Connect (OSTI)

    Firoozabadi, Dr. Abbas

    2000-01-18

    In this report the results of experiments of water injection in fractured porous media comprising a number of water-wet matrix blocks are reported for the first time. The blocks experience an advancing fracture-water level (FWL). Immersion-type experiments are performed for comparison; the dominant recovery mechanism changed from co-current to counter-current imbibition when the boundary conditions changed from advancing FWL to immersion-type. Single block experiments of co-current and counter-current imbibition was performed and co-current imbibition leads to more efficient recovery was found.

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

    SciTech Connect (OSTI)

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

    2010-11-01

    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.

  14. Fracture Mechanics and Failure Analysis

    E-Print Network [OSTI]

    New South Wales, University of

    concepts: Griffith criterion, K=Ya, K=KIC, ductile and brittle fracture, cyclic fatigue, environmentally, yield criteria. 4 Elastic-Plastic Analysis 5 Fracture toughness testing 6 Crack Growth Resistance - RMATS4004 Fracture Mechanics and Failure Analysis Course Outline Session 1, 2015 School of Materials

  15. Infiltration into Fractured Bedrock

    SciTech Connect (OSTI)

    Salve, Rohit; Ghezzehei, Teamrat A.; Jones, Robert

    2007-09-01

    One potential consequence of global climate change and rapid changes in land use is an increased risk of flooding. Proper understanding of floodwater infiltration thus becomes a crucial component of our preparedness to meet the environmental challenges of projected climate change. In this paper, we present the results of a long-term infiltration experiment performed on fractured ash flow tuff. Water was released from a 3 x 4 m{sup 2} infiltration plot (divided into 12 square subplots) with a head of {approx}0.04 m, over a period of {approx}800 days. This experiment revealed peculiar infiltration patterns not amenable to current infiltration models, which were originally developed for infiltration into soils over a short duration. In particular, we observed that in part of the infiltration plot, the infiltration rate abruptly increased a few weeks into the infiltration tests. We suggest that these anomalies result from increases in fracture permeability during infiltration, which may be caused by swelling of clay fillings and/or erosion of infill debris. Interaction of the infiltration water with subsurface natural cavities (lithophysal cavities) could also contribute to such anomalies. This paper provides a conceptual model that partly describes the observed infiltration patterns in fractured rock and highlights some of the pitfalls associated with direct extension of soil infiltration models to fractured rock over a long period.

  16. 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]

    Paris-Sud XI, Université de

    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

  17. Fracture-resistant lanthanide scintillators

    DOE Patents [OSTI]

    Doty, F. Patrick (Livermore, CA)

    2011-01-04

    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.

  18. Correlating toughness and roughness in ductile fracture

    E-Print Network [OSTI]

    Laurent Ponson; Ankit Srivastava; Shmulik Osovski; Elisabeth Bouchaud; Viggo Tvergaard; Alan Needleman

    2013-07-16

    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 correlation length of the fracture surface corresponding to the cut-off of the self-affine behavior is found to be linearly related to JIC thus quantitatively correlating toughness and fracture surface roughness.

  19. Indirect fracture delineation in a carbonate reservoir: The Upper Jurassic Hanifa of Abqaiq field, Saudi Arabia

    SciTech Connect (OSTI)

    Bailey, D.L. (Saudi Aramco, Dhahran (Saudi Arabia))

    1991-03-01

    Abqaiq field is a northeast-trending anticline approximately 60 km long and 12 km wide and contains several reservoirs. The Hanifa Reservoir is approximately 100 m thick and consists of fine-grained, muddy limestone with subordinate dolomite and anhydrite. Since discovery of the Hanifa oil pool in 1947, pressure fluctuations have indicated communication with the overlying Arab-D Reservoir. Welltest permeability measurements are approximately 40 times higher than core permeability measurements of the Hanifa. This divergence of Hanifa permeability measurements combined with the indicated Arab-D communication suggests the presence of a natural fracture network. Direct observations of Hanifa cores reveal common, sub-vertical fractures with average apertures <200 microns. With limited core coverage and no oriented cores, a new technique was needed to delineate the areas affected by fractures. A technique combining indirect fracture indicators was devised for Abqaiq field and can be applied to other, similar fields. The actual flow system of the Abqaiq Hanifa is a complex interaction between matrix porosity/permeability and fracture permeability or enhanced permeability. Future development plans allow for low matrix permeability access to much of the Hanifa storage space and high fracture permeability both within the Hanifa and connecting to the Arab-D Reservoir.

  20. Computational study of ion beam extraction phenomena through multiple apertures

    SciTech Connect (OSTI)

    Hu, Wanpeng; Sang, Chaofeng; Tang, Tengfei; Wang, Dezhen, E-mail: wangdez@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)] [Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Li, Ming; Jin, Dazhi; Tan, Xiaohua [Institute of Electronic Engineering, Mianyang, 621900 (China)] [Institute of Electronic Engineering, Mianyang, 621900 (China)

    2014-03-15

    The process of ion extraction through multiple apertures is investigated using a two-dimensional particle-in-cell code. We consider apertures with a fixed diameter with a hydrogen plasma background, and the trajectories of electrons, H{sup +} and H{sub 2}{sup +} ions in the self-consistently calculated electric field are traced. The focus of this work is the fundamental physics of the ion extraction, and not particular to a specific device. The computed convergence and divergence of the extracted ion beam are analyzed. We find that the extracted ion flux reaching the extraction electrode is non-uniform, and the peak flux positions change according to operational parameters, and do not necessarily match the positions of the apertures in the y-direction. The profile of the ion flux reaching the electrode is mainly affected by the bias voltage and the distance between grid wall and extraction electrode.

  1. Synthetic aperture integration (SAI) algorithm for SAR imaging

    DOE Patents [OSTI]

    Chambers, David H; Mast, Jeffrey E; Paglieroni, David W; Beer, N. Reginald

    2013-07-09

    A method and system for detecting the presence of subsurface objects within a medium is provided. In some embodiments, the imaging and detection system operates in a multistatic mode to collect radar return signals generated by an array of transceiver antenna pairs that is positioned across the surface and that travels down the surface. The imaging and detection system pre-processes the return signal to suppress certain undesirable effects. The imaging and detection system then generates synthetic aperture radar images from real aperture radar images generated from the pre-processed return signal. The imaging and detection system then post-processes the synthetic aperture radar images to improve detection of subsurface objects. The imaging and detection system identifies peaks in the energy levels of the post-processed image frame, which indicates the presence of a subsurface object.

  2. INTERPRETATION OF A HYDRAULIC FRACTURING EXPERIMENT, MONTICELLO, SOUTH CAROLINA

    E-Print Network [OSTI]

    Narasimhan, T.N.

    2014-01-01

    OF A HYDRAULIC FRACTURING EXPERIMENT, MONTICELLO, SOUTHOF A HYDRAULIC FRACTURING EXPERIMENT, MONTICELLO, SOUTHdata from a hydraulic fracturing experiment have been

  3. Resolution and synthetic aperture characterization of sparse radar arrays

    E-Print Network [OSTI]

    Stiles, James Marion; Goodman, N. A.

    2003-07-01

    : RESOLUTION AND SYNTHETIC APERTURE CHARACTERIZATION 923 position in each of three spatial directions. These are, by definition, the spatial frequencies k x (x), k y (x), and k z (x) of the wave scattered from a target at x. Likewise, the fourth term provides..., the transmitting antenna can be focused on the mean scatterer location ¯ x by forcing a phase taper of ª a (l)=#0;?(k 0 l ) † ¢l: (24) Then, the transmit pattern is g(x)= #0;= S A #0;Mw l (l)#0;Mexp(#0;?j¢x † ¤ l ¢l)dl: (25) B. Synthetic Aperture Interpretation...

  4. Hydrogen-Assisted Fracture: Materials Testing and Variables Governing...

    Office of Environmental Management (EM)

    Hydrogen-Assisted Fracture: Materials Testing and Variables Governing Fracture Hydrogen-Assisted Fracture: Materials Testing and Variables Governing Fracture SNL has 40+ years...

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

    SciTech Connect (OSTI)

    Mukul M. Sharma

    2005-03-01

    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.

  6. Seismic waves in rocks with fluids and fractures

    SciTech Connect (OSTI)

    Berryman, J.G.

    2007-05-14

    Seismic wave propagation through the earth is often stronglyaffected by the presence of fractures. When these fractures are filledwith fluids (oil, gas, water, CO2, etc.), the type and state of the fluid(liquid or gas) can make a large difference in the response of theseismic waves. This paper summarizes recent work on methods ofdeconstructing the effects of fractures, and any fluids within thesefractures, on seismic wave propagation as observed in reflection seismicdata. One method explored here is Thomsen's weak anisotropy approximationfor wave moveout (since fractures often induce elastic anisotropy due tononuniform crack-orientation statistics). Another method makes use ofsome very convenient fracture parameters introduced previously thatpermit a relatively simple deconstruction of the elastic and wavepropagation behavior in terms of a small number of fracture parameters(whenever this is appropriate, as is certainly the case for small crackdensities). Then, the quantitative effects of fluids on thesecrack-influence parameters are shown to be directly related to Skempton scoefficient B of undrained poroelasticity (where B typically ranges from0 to 1). In particular, the rigorous result obtained for the low crackdensity limit is that the crack-influence parameters are multiplied by afactor (1 ? B) for undrained systems. It is also shown how fractureanisotropy affects Rayleigh wave speed, and how measured Rayleigh wavespeeds can be used to infer shear wave speed of the fractured medium.Higher crack density results are also presented by incorporating recentsimulation data on such cracked systems.

  7. Phase Field Fracture Mechanics.

    SciTech Connect (OSTI)

    Robertson, Brett Anthony

    2015-11-01

    For this assignment, a newer technique of fracture mechanics using a phase field approach, will be examined and compared with experimental data for a bend test and a tension test. The software being used is Sierra Solid Mechanics, an implicit/explicit finite element code developed at Sandia National Labs in Albuquerque, New Mexico. The bend test experimental data was also obtained at Sandia Labs while the tension test data was found in a report online from Purdue University.

  8. Procedure for estimating fracture energy from fracture surface roughness

    DOE Patents [OSTI]

    Williford, Ralph E. (Kennewick, WA)

    1989-01-01

    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.

  9. Reservoir monitoring and characterization using satellite geodetic data: Interferometric Synthetic Aperture Radar observations from the Krechba field, Algeria

    SciTech Connect (OSTI)

    Vasco, D.W.; Ferretti, Alessandro; Novali, Fabrizio

    2008-05-01

    Deformation in the material overlying an active reservoir is used to monitor pressure change at depth. A sequence of pressure field estimates, eleven in all, allow us to construct a measure of diffusive travel time throughout the reservoir. The dense distribution of travel time values means that we can construct an exactly linear inverse problem for reservoir flow properties. Application to Interferometric Synthetic Aperture Radar (InSAR) data gathered over a CO{sub 2} injection in Algeria reveals pressure propagation along two northwest trending corridors. An inversion of the travel times indicates the existence of two northwest-trending high permeability zones. The high permeability features trend in the same direction as the regional fault and fracture zones. Model parameter resolution estimates indicate that the features are well resolved.

  10. Brittle Fracture Ductile to Brittle transition

    E-Print Network [OSTI]

    Subramaniam, Anandh

    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

  11. Technical Evaluation Report "Baseline Design for the COS Aperture Plate"

    E-Print Network [OSTI]

    Colorado at Boulder, University of

    Technical Evaluation Report "Baseline Design for the COS Aperture Plate" Date: October 14, 1999 Document Number: COS-11-0009 Revision: Initial Release Contract No.: NAS5-98043 CDRL No.: SE-05 Prepared By: J. Morse, COS Project Scientist, CU/CASA Date Reviewed By: E. Wilkinson, COS Instrument Scientist

  12. Imaging Fourier transform spectroscopy with multi-aperture telescopes

    E-Print Network [OSTI]

    Fienup, James R.

    Imaging Fourier transform spectroscopy with multi-aperture telescopes Samuel T. Thurman and James R Hanover St., Palo Alto, CA 94304 Abstract: Fourier spectroscopy can be performed with multi Society of America OCIS codes: (300.6300) Spectroscopy, Fourier transforms; (110.6770) Telescopes; (120

  13. Multiple Instrument Distributed Aperture Sensor (MIDAS) For Remote Sensing

    E-Print Network [OSTI]

    Fienup, James R.

    Multiple Instrument Distributed Aperture Sensor (MIDAS) For Remote Sensing Joe Pitman,a , Alan that enables greatly increased return from earth and planetary science remote sensing missions is described are integrated into MIDAS as the primary remote sensing science payload, thereby reducing the cost, resources

  14. Passive Synthetic Aperture Radar Imaging of Ground Moving Targets

    E-Print Network [OSTI]

    Yazici, Birsen

    waves due to illuminating sources of opportunity such as commercial television, radio, and cell phone of opportunity such as radio, cell phone, and television transmission towers. The absence of active signal synthetic aperture radar. A passive radar imaging system uses small, mobile receivers that do not radiate

  15. Microwave-induced thermoacoustic tomography: Reconstruction by synthetic aperture

    E-Print Network [OSTI]

    Wang, Lihong

    Microwave-induced thermoacoustic tomography: Reconstruction by synthetic aperture Dazi Feng, Yuan thermoacoustic signals, to which the delay-and-sum algorithm was applied for image reconstruc- tion. We greatly-induced thermoacoustic tomography based on focused transducers. Two mi- crowave sources, which had frequencies of 9 and 3

  16. FRACTURED PETROLEUM RESERVOIRS

    SciTech Connect (OSTI)

    Abbas Firoozabadi

    1999-06-11

    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.

  17. Fracture-Induced Anisotropic Attenuation

    E-Print Network [OSTI]

    2012-03-23

    (the lossless elastic limit) times one unit of time. The SH wave energy velocity is ..... Technology. Hood JA (1991) A simple method for decomposing fracture- ...

  18. Seismic anisotropy of fractured rock

    E-Print Network [OSTI]

    M. Schoenberg, C. M. Sayers

    2000-02-18

    anisotropic media: Pure Appl. Geophys., 58, 53-112. Henyey ... simulated fractured medium: Geophysics, 58, 964-977. Hudson ... ASCE, 106, 1039-1051. 1992 ...

  19. Correlating toughness and roughness in ductile fracture

    E-Print Network [OSTI]

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

    2013-01-01

    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...

  20. Interferometric hydrofracture microseism localization using neighboring fracture

    E-Print Network [OSTI]

    Poliannikov, Oleg V.

    2011-05-19

    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. ...

  1. On the fracture toughness of advanced materials

    E-Print Network [OSTI]

    Launey, Maximilien E.

    2009-01-01

    higher intrinsic toughness For ductile fracture, conversely,of fracture resistance and toughness. In ductile materialsductile, i.e. , microvoid coalescence, fracture, which is locally strain-controlled and generally results in much higher toughness.

  2. Interferometric hydrofracture microseism localization using neighboring fracture

    E-Print Network [OSTI]

    Poliannikov, Oleg V.

    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. ...

  3. Discrete Fracture Reservoir Simulation

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit theCovalentLaboratory | National NuclearDiscoveringDiscrete Fracture Reservoir

  4. May 2004 1st Annual EMRS DTC Conf Optical Aperture Synthesis

    E-Print Network [OSTI]

    Greenaway, Alan

    May 2004 1st Annual EMRS DTC Conf Optical Aperture Synthesis 1 Optical Aperture Synthesis Alan UK #12;May 2004 1st Annual EMRS DTC Conf Optical Aperture Synthesis 2 Outline · Introduction ­ Objectives and Benefits ­ Background ­ Principles · Programme ­ Risk Analysis ­ Risk Mitigation #12;May 2004

  5. Development of hydraulic-fracturing models for application to coal-seam methane drainage. Final report, January 17, 1983-June 30, 1984

    SciTech Connect (OSTI)

    Hanson, M.E.; Mavko, B.B.; Thorson, L.D.

    1985-03-29

    The objective of this project is to develop two- and three-dimensional models the industry can use to design and understand hydraulic fracture treatments for stimulating methane production from coal seams. Initially, two-dimensional models were used to study pressure-driven fractures near a stress barrier. The results illustrated that barriers can arrest fracture propagation, cause the wetted length to approach the fracture tip, and change the aperture shape. It became clear that 3-dimensional calculations were necessary for analysis of the coal-seam problem. Work was begun on the circular model, the simplest of the 3-D models. It was determined that the fluid-flow equations using the common uniform-aperture approximation do not properly conserve mass when the flow slot varies with position and time. The problem was corrected by carefully combining the equations for radial flow and the elasticity equations for governing aperture. The model was successfully applied to show the effects of changes in rates, viscosities, and elastic modulus.

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

    SciTech Connect (OSTI)

    Liu, H.H.; Rutqvist, J.

    2009-10-01

    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.

  7. Wave Propagation in Fractured Poroelastic Media

    E-Print Network [OSTI]

    robiel

    instance, tectonic stresses and natural or artificial hydraulic fracturing caused ... Seismic wave propagation through fractures and cracks is an important subject ...

  8. Collateral damage: Evolution with displacement of fracture distribution and secondary fault strands in fault

    E-Print Network [OSTI]

    Savage, Heather M.

    Collateral damage: Evolution with displacement of fracture distribution and secondary fault strands in fault damage zones Heather M. Savage1,2 and Emily E. Brodsky1 Received 22 April 2010; revised 10 of fracture distributions as a function of displacement to determine whether damage around small and large

  9. Fracture Processes Observed with A Cryogenic Detector

    E-Print Network [OSTI]

    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

    2006-03-21

    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 .

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

    SciTech Connect (OSTI)

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

    1997-08-01

    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.

  11. Chemical Signatures of and Precursors to Fractures Using Fluid Inclusion Stratigraphy

    SciTech Connect (OSTI)

    Lorie M. Dilley

    2011-03-30

    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.

  12. Transmission of Megawatt Relativistic Electron Beams Through Millimeter Apertures

    E-Print Network [OSTI]

    R. Alarcon; S. Balascuta; S. V. Benson; W. Bertozzi; J. R. Boyce; R. Cowan; D. Douglas; P. Evtushenko; P. Fisher; E. Ihloff; N. Kalantarians; A. Kelleher; R. Legg; R. G. Milner; G. R. Neil; L. Ou; B. Schmookler; C. Tennant; C. Tschalaer; G. P. Williams; S. Zhang

    2013-05-01

    High power, relativistic electron beams from energy recovery linacs have great potential to realize new experimental paradigms for pioneering innovation in fundamental and applied research. A major design consideration for this new generation of experimental capabilities is the understanding of the halo associated with these bright, intense beams. In this Letter, we report on measurements performed using the 100 MeV, 430 kWatt CW electron beam from the energy recovery linac at the Jefferson Laboratory's Free Electron Laser facility as it traversed a set of small apertures in a 127 mm long aluminum block. Thermal measurements of the block together with neutron measurements near the beam-target interaction point yielded a consistent understanding of the beam losses. These were determined to be 3 ppm through a 2 mm diameter aperture and were maintained during a 7 hour continuous run.

  13. *Corresponding author: pawel.woelke@wai.com; Tel.: +1 212 367 2983; Fax: +1 212 497 2483 SIMULATIONS OF DUCTILE FRACTURE IN AN IDEALIZED SHIP GROUNDING

    E-Print Network [OSTI]

    Hutchinson, John W.

    SIMULATIONS OF DUCTILE FRACTURE IN AN IDEALIZED SHIP GROUNDING SCENARIO USING PHENOMENOLOGICAL DAMAGE methodologies for ductile fracture in large sheet metal components are presented and evaluated in this paper-separation law is employed to simulate the same ductile fracture problems accounting for significant variation

  14. Fracture and Healing of Rock Salt Related to Salt Caverns

    SciTech Connect (OSTI)

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

    1999-03-01

    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.

  15. Modeling the Fracture of Ice Sheets on Parallel Computers

    SciTech Connect (OSTI)

    Waisman, Haim; Tuminaro, Ray

    2013-10-10

    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.

  16. TEMPORAL VARIATIONS OF FRACTURE DIRECTIONS AND FRACTURE DENSITIES...

    Open Energy Info (EERE)

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

  17. Self-potential observations during hydraulic fracturing

    E-Print Network [OSTI]

    Moore, Jeffrey R.; Glaser, Steven D.

    2008-01-01

    assumption that fluid flow is laminar; an assumption thatspecimens, fluid flow prior to fracturing remains laminar

  18. Self-potential observations during hydraulic fracturing

    E-Print Network [OSTI]

    Moore, J R; Glaser, Steven D

    2007-01-01

    assumption that fluid flow is laminar; an assumption thatspecimens, fluid flow prior to fracturing remains laminar

  19. The FRAC Act: The Fracturing Responsibility and

    E-Print Network [OSTI]

    Smerdon, Jason E.

    ;4 Hydraulic fracturing, commonly referred to as hydrofracking or fracking, is a technology used to stimulate

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

    E-Print Network [OSTI]

    Ritchie, Robert

    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

  1. elastic wave propagation in media with parallel fractures and ...

    E-Print Network [OSTI]

    M . SCHOENBERG2 and J . DOUMA

    2002-02-14

    A model of parallel slip interfaces simulates the behaviour of a fracture system composed of large, closely .... Note that when the ith constituent layer is isotropic, c44i = c66i = pi, clli = c,,~ = ,Ii + 2pi and .... Thus (14) becomes. Define the .... system's characteristic properties, such as crack size, crack density or the contents of.

  2. Water Use for Hydraulic Fracturing: A Texas Sized Problem? 

    E-Print Network [OSTI]

    LeClere, David

    2014-01-01

    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...

  3. Remarks on "Piezonuclear neutrons from fracturing of inert solids"

    E-Print Network [OSTI]

    Giovanni Comoretto; Marco Prevedelli

    2012-06-08

    In two series of measurements, Cardone, Carpinteri et al. report an excess of neutrons over the background flux corresponding to the catastrophic fracture of a granite block subject to compression. Here we show that these measurements contain large inconsistencies with respect to the stated experimental procedure, including fractional neutron counts and strongly non Poissonian statistics

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

    E-Print Network [OSTI]

    Fletcher, Sarah Marie

    2012-01-01

    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 ...

  5. FRACTURE STIMULATION IN ENHANCED GEOTHERMAL

    E-Print Network [OSTI]

    Stanford University

    FRACTURE STIMULATION IN ENHANCED GEOTHERMAL SYSTEMS A REPORT SUBMITTED TO THE DEPARTMENT OF ENERGY (Principal Advisor) #12;#12;v Abstract Enhanced Geothermal Systems (EGS) are geothermal reservoirs formed

  6. Fracture of aluminum naval structures

    E-Print Network [OSTI]

    Galanis, Konstantinos, 1970-

    2007-01-01

    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. ...

  7. Sensitivity analysis of fracture scattering

    E-Print Network [OSTI]

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

    2010-01-01

    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, ...

  8. Design and Implementation of Energized Fracture Treatment in Tight Gas Sands

    SciTech Connect (OSTI)

    Mukul Sharma; Kyle Friehauf

    2009-12-31

    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.

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

    E-Print Network [OSTI]

    Ogbechie, Joachim Nwabunwanne

    2012-02-14

    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...

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

    E-Print Network [OSTI]

    Bakku, Sudhish Kumar

    2011-01-01

    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 ...

  11. Comparison of Discrete Fracture and Effective Media Representation of Fractures on Azimuthal AVO

    E-Print Network [OSTI]

    Zhang, Yang

    2005-01-01

    In fractured reservoir development, azimuthal AVO (AVOaz) properties of reflected PP waves from reservoir tops are often used to infer fracture properties. The fracture parameter inversion is based on either an effective ...

  12. Apodized RFI filtering of synthetic aperture radar images.

    SciTech Connect (OSTI)

    Doerry, Armin Walter

    2014-02-01

    Fine resolution Synthetic Aperture Radar (SAR) systems necessarily require wide bandwidths that often overlap spectrum utilized by other wireless services. These other emitters pose a source of Radio Frequency Interference (RFI) to the SAR echo signals that degrades SAR image quality. Filtering, or excising, the offending spectral contaminants will mitigate the interference, but at a cost of often degrading the SAR image in other ways, notably by raising offensive sidelobe levels. This report proposes borrowing an idea from nonlinear sidelobe apodization techniques to suppress interference without the attendant increase in sidelobe levels. The simple post-processing technique is termed Apodized RFI Filtering (ARF).

  13. High numerical aperture projection system for extreme ultraviolet projection lithography

    DOE Patents [OSTI]

    Hudyma, Russell M. (San Ramon, CA)

    2000-01-01

    An optical system is described that is compatible with extreme ultraviolet radiation and comprises five reflective elements for projecting a mask image onto a substrate. The five optical elements are characterized in order from object to image as concave, convex, concave, convex, and concave mirrors. The optical system is particularly suited for ring field, step and scan lithography methods. The invention uses aspheric mirrors to minimize static distortion and balance the static distortion across the ring field width which effectively minimizes dynamic distortion. The present invention allows for higher device density because the optical system has improved resolution that results from the high numerical aperture, which is at least 0.14.

  14. Coded aperture imaging with self-supporting uniformly redundant arrays

    DOE Patents [OSTI]

    Fenimore, Edward E. (Los Alamos, NM)

    1983-01-01

    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.

  15. Phase correction system for automatic focusing of synthetic aperture radar

    DOE Patents [OSTI]

    Eichel, Paul H. (Albuquerque, NM); Ghiglia, Dennis C. (Placitas, NM); Jakowatz, Jr., Charles V. (Albuquerque, NM)

    1990-01-01

    A phase gradient autofocus system for use in synthetic aperture imaging accurately compensates for arbitrary phase errors in each imaged frame by locating highlighted areas and determining the phase disturbance or image spread associated with each of these highlight areas. An estimate of the image spread for each highlighted area in a line in the case of one dimensional processing or in a sector, in the case of two-dimensional processing, is determined. The phase error is determined using phase gradient processing. The phase error is then removed from the uncorrected image and the process is iteratively performed to substantially eliminate phase errors which can degrade the image.

  16. Fracture induced anisotropy in viscoelastic UNLP, 11 Octubre de 2012

    E-Print Network [OSTI]

    Santos, Juan

    of earthquakes, and hydrocarbon and geothermal reservoirs are mainly composed of fractured rocks. Fracture: horizontal and vertical coordinates, respectively. When a dense set of parallel fractures is present

  17. INTERPRETATION OF A HYDRAULIC FRACTURING EXPERIMENT, MONTICELLO, SOUTH CAROLINA

    E-Print Network [OSTI]

    Narasimhan, T.N.

    2014-01-01

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

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

    E-Print Network [OSTI]

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

    2000-01-01

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

  19. Aperture Photometry of Saturated Star Images from Digitised Photographic Plates

    E-Print Network [OSTI]

    J. L. Innis; D. W. Coates; A. P. Borisova; M. K. Tsvetkov

    2005-02-21

    Saturated stellar images on digitised photographic plates are many times greater in area than the `seeing disk' seen in unsaturated CCD images. Indeed the flux profile of a bright star can be traced out for several degrees from the star's centre. The radius of the saturated stellar image can often be directly related to the magnitude of the star, a fact well known and exploited in iris photometry. In this work we compare the radial flux profile of stars in the approximate range B ~9 to ~13 mag, obtained from scans of plates from the Bamberg Sky Patrol archive, with a profile of the form measured by King. We show that simple aperture photometry of saturated stellar images, obtained from photo-positives of scanned photographic plates, yield data that are in agreement with simulations using a (saturated) synthetic stellar radius profile. Raw plate magnitudes from this aperture photometry can be easily and satisfactorily transformed to standard magnitudes, as demonstrated in a recent study carried out by the current authors.

  20. Optimization of the Dynamic Aperture for SPEAR3 Low-Emittance...

    Office of Scientific and Technical Information (OSTI)

    require a damping wiggler. There is a smaller dynamic aperture for the lower emittance optics due to a stronger nonlinearity. Elegant based Multi-Objective Genetic Algorithm (MOGA)...

  1. Three-dimensional hydraulic fracture model development for application to and understanding of coal-bed methane-stimulation treatments. Final report, July 1, 1984-December 16, 1988

    SciTech Connect (OSTI)

    Mavko, B.B.; Nielsen, P.E.; Hanson, M.E.

    1989-03-01

    A preliminary three-dimensional numerical model was developed to simulate hydraulically driven fracturing for application to coal seam methane drainage. The initial focus was development of a circular fracture model which served, in part, as a test bed for concepts and formulations applicable to the more general three-dimensional model. Findings from circular model studies were used to design a multiseam fracture treatment. The three-dimensional model involved development of exact influence coefficients for the elastic calculations, inclusion of the aperture time derivative, implementation of an equilibrium tip condition, incorporation of modulus and stress layering, dynamic grid rezoning, incorporation of a two-dimensional fluid flow solution, implementation of the applicable fluid flow boundary conditions, development of a physically realistic fracture front propagation scheme, and proper coupling and control of the various fracture, flow, and calculational model components. Model simulations illustrate important physical effects of fracturing in coal. Preliminary simulations are discussed which show the effects of different viscosity fluids, and effects of stress and modulus variations on vertical fracture containment.

  2. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDid you notHeat PumpsTechnologies | Blandine Jerome Lanfang Zou

  3. Fractured rock stress-permeability relationships from in situ data and effects of temperature and chemical-mechanical couplings

    SciTech Connect (OSTI)

    Rutqvist, J.

    2014-09-19

    The purpose of this paper is to (i) review field data on stress-induced permeability changes in fractured rock; (ii) describe estimation of fractured rock stress-permeability relationships through model calibration against such field data; and (iii) discuss observations of temperature and chemically mediated fracture closure and its effect on fractured rock permeability. The field data that are reviewed include in situ block experiments, excavation-induced changes in permeability around tunnels, borehole injection experiments, depth (and stress) dependent permeability, and permeability changes associated with a large-scale rock-mass heating experiment. Data show how the stress-permeability relationship of fractured rock very much depends on local in situ conditions, such as fracture shear offset and fracture infilling by mineral precipitation. Field and laboratory experiments involving temperature have shown significant temperature-driven fracture closure even under constant stress. Such temperature-driven fracture closure has been described as thermal overclosure and relates to better fitting of opposing fracture surfaces at high temperatures, or is attributed to chemically mediated fracture closure related to pressure solution (and compaction) of stressed fracture surface asperities. Back-calculated stress-permeability relationships from field data may implicitly account for such effects, but the relative contribution of purely thermal-mechanical and chemically mediated changes is difficult to isolate. Therefore, it is concluded that further laboratory and in situ experiments are needed to increase the knowledge of the true mechanisms behind thermally driven fracture closure, and to further assess the importance of chemical-mechanical coupling for the long-term evolution of fractured rock permeability.

  4. Fractured rock stress-permeability relationships from in situ data and effects of temperature and chemical-mechanical couplings

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

    Rutqvist, J.

    2014-09-19

    The purpose of this paper is to (i) review field data on stress-induced permeability changes in fractured rock; (ii) describe estimation of fractured rock stress-permeability relationships through model calibration against such field data; and (iii) discuss observations of temperature and chemically mediated fracture closure and its effect on fractured rock permeability. The field data that are reviewed include in situ block experiments, excavation-induced changes in permeability around tunnels, borehole injection experiments, depth (and stress) dependent permeability, and permeability changes associated with a large-scale rock-mass heating experiment. Data show how the stress-permeability relationship of fractured rock very much depends on localmore »in situ conditions, such as fracture shear offset and fracture infilling by mineral precipitation. Field and laboratory experiments involving temperature have shown significant temperature-driven fracture closure even under constant stress. Such temperature-driven fracture closure has been described as thermal overclosure and relates to better fitting of opposing fracture surfaces at high temperatures, or is attributed to chemically mediated fracture closure related to pressure solution (and compaction) of stressed fracture surface asperities. Back-calculated stress-permeability relationships from field data may implicitly account for such effects, but the relative contribution of purely thermal-mechanical and chemically mediated changes is difficult to isolate. Therefore, it is concluded that further laboratory and in situ experiments are needed to increase the knowledge of the true mechanisms behind thermally driven fracture closure, and to further assess the importance of chemical-mechanical coupling for the long-term evolution of fractured rock permeability.« less

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

    E-Print Network [OSTI]

    Kim, Tae Hyung

    2009-05-15

    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...

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

    E-Print Network [OSTI]

    Correa Castro, Juan

    2011-08-08

    concentrations under reservoirs conditions. The result of this study provides the basis to optimize the fracturing fluids and the polymer loading at different reservoir conditions, which may result in a clean and conductive fracture. Success in improving...

  7. Method for directional hydraulic fracturing

    DOE Patents [OSTI]

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

    1994-01-01

    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.

  8. GMINC - A MESH GENERATOR FOR FLOW SIMULATIONS IN FRACTURED RESERVOIRS

    E-Print Network [OSTI]

    Pruess, K.

    2010-01-01

    the Production of Superheated Steam from Fractured, Vapor-THE PRODUCTION OF SUPERHEATED STEAM FROM FRACTURED, VAPOR-

  9. Harmonic experiments to model fracture induced anisotropy

    E-Print Network [OSTI]

    Santos, Juan

    of earthquakes, and hydrocarbon and geothermal reservoirs are mainly composed of fractured rocks. Harmonic and vertical coordinates, respectively. When a dense set of parallel fractures is present, the medium behaves

  10. Self-potential observations during hydraulic fracturing

    E-Print Network [OSTI]

    Moore, Jeffrey R.; Glaser, Steven D.

    2008-01-01

    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

  11. Modeling of Acid Fracturing in Carbonate Reservoirs 

    E-Print Network [OSTI]

    Al Jawad, Murtada s

    2014-06-05

    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...

  12. Lisburne Formation fracture characterization and flow modeling 

    E-Print Network [OSTI]

    Karpov, Alexandre Valerievich

    2001-01-01

    Evaluation of fractured reservoirs for fluid flow and optimal well placement is often very complicated. In general, fractures enhance permeability and increase access to matrix surface, but their random aspects create difficulties for analysis...

  13. Acoustic Character Of Hydraulic Fractures In Granite

    E-Print Network [OSTI]

    Paillet, Frederick I.

    1983-01-01

    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 ...

  14. 1Plastic deformation and fracture processes in metallic and ceramic nanomaterials... 2007 Advanced Study Center Co. Ltd.

    E-Print Network [OSTI]

    Ovid'ko Ilya A.

    compositions of large grains and the nanocrystalline matrix can be either identical or different. Obviously1Plastic 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

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

    E-Print Network [OSTI]

    Lu, Zhiming

    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

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

    E-Print Network [OSTI]

    Grujicic, Mica

    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

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

    E-Print Network [OSTI]

    Ritchie, Robert

    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

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

    E-Print Network [OSTI]

    Espinosa, Horacio D.

    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

  19. Hybrid Compton camera/coded aperture imaging system

    DOE Patents [OSTI]

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

    2012-04-10

    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.

  20. Time-frequency analysis of synthetic aperture radar signals

    SciTech Connect (OSTI)

    Johnston, B.

    1996-08-01

    Synthetic aperture radar (SAR) has become an important tool for remote sensing of the environment. SAR is a set of digital signal processing algorithms that are used to focus the signal returned to the radar because radar systems in themselves cannot produce the high resolution images required in remote sensing applications. To reconstruct an image, several parameters must be estimated and the quality of output image depends on the degree of accuracy of these parameters. In this thesis, we derive the fundamental SAR algorithms and concentrate on the estimation of one of its critical parameters. We show that the common technique for estimating this particular parameter can sometimes lead to erroneous results and reduced quality images. We also employ time-frequency analysis techniques to examine variations in the radar signals caused by platform motion and show how these results can be used to improve output image quality.

  1. Numerical aperture influence on 3-D multi-layer optical data storage systems , Edwin P. Walkera

    E-Print Network [OSTI]

    Esener, Sadik C.

    Numerical aperture influence on 3-D multi-layer optical data storage systems Yi Zhanga* , Edwin P storage system is analyzed. Keywords: NA, multi-layer data storage, two-photon recording, capacity) 550-0596, Fax: (858) 550-0917 #12;Numerical aperture influence on 3-D multi-layer optical data storage

  2. New Aperture and PSF Photometry QSO 0957+561A,B

    E-Print Network [OSTI]

    Ovaldsen, Jan-Erik

    New Aperture and PSF Photometry of QSO 0957+561A,B Application to Time Delay and Microlensing Aperture and PSF Photometry of QSO 0957+561A,B", is distributed under the terms of the Public Library was initiated with the aim of developing a photometry program to reduce the CCD frames. The results were

  3. Optical snow and the aperture problem Richard Mann Michael S. Langer

    E-Print Network [OSTI]

    Mann, Richard

    Optical snow and the aperture problem Richard Mann Michael S. Langer School of Computer Science motion in a cluttered 3-D scene or a stationary camera viewing falling snow. We refer to these image motions as optical snow. In the present paper, we show how the aperture problem manifests itself

  4. Aperture synthesis of time-limited X waves and analysis of their propagation characteristics

    E-Print Network [OSTI]

    Lu, Jian-yu

    of Engineering Physics and Mathematics, Faculty of Engineering Cairo University, Giza, Egypt Ioannis M. Besieris of the FWM pulse does not require infinite power. This is the case because as the generating aperture becomes of the aperture increases as (ct)2 . These two effects balance each other and the power of the excitation wave

  5. Aperture Synthesis Observations of the Nearby Spiral NGC 6503: Modeling the Thin and Thick HI Disks

    E-Print Network [OSTI]

    Greisen, Eric

    Aperture Synthesis Observations of the Nearby Spiral NGC 6503: Modeling the Thin and Thick HI Disks aperture synthesis observations of the nearby, late­type spiral galaxy NGC 6503, and produce HI maps field, while remarkably regular, contains clear evidence for irregularities. The HI is distributed over

  6. Aperture Synthesis Observations of the Nearby Spiral NGC 6503: Modeling the Thin and Thick HI Disks

    E-Print Network [OSTI]

    Greisen, Eric

    Aperture Synthesis Observations of the Nearby Spiral NGC 6503: Modeling the Thin and Thick HI Disks aperture synthesis observations of the nearby, late-type spiral galaxy NGC 6503, and produce HI maps field, while remarkably regular, contains clear evidence for irregularities. The HI is distributed over

  7. Super-resolution in incoherent optical imaging using synthetic aperture with Fresnel elements

    E-Print Network [OSTI]

    Rosen, Joseph

    Super-resolution in incoherent optical imaging using synthetic aperture with Fresnel elements Barak the Rayleigh limit of the system is obtained by tiling digitally several Fresnel holographic elements into a complete Fresnel hologram of the observed object. Each element is acquired by the limited-aperture system

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

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

    Successful Exploration Strategies in Extended Terranes Finding Large Aperture Fractures in Geothermal Resource Areas Using a Three-Component Long-Offset Surface Seismic Survey...

  9. Comprehensive Evaluation of the Geothermal Potential within the...

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

    Paiute Reservation GBCGE Resarch, Education and Outreach Finding Large Aperture Fractures in Geothermal Resource Areas Using a Three-Component Long-Offset Surface Seismic Survey...

  10. Regulation of Hydraulic Fracturing in California

    E-Print Network [OSTI]

    Kammen, Daniel M.

    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

  11. Hydraulic Fracture: multiscale processes and moving

    E-Print Network [OSTI]

    Peirce, Anthony

    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

  12. Identifying Best Practices in Hydraulic Fracturing Using

    E-Print Network [OSTI]

    Mohaghegh, Shahab

    Identifying Best Practices in Hydraulic Fracturing Using Virtual Intelligence Techniques SPE 72385 Results & Discussion Conclusion #12;SPE 72385 OBJECTIVE To identify Best Practices in Hydraulic Fracturing, are fractured upon completion to provide economic amounts of gas. #12;SPE 72385 BACKGROUND A dataset

  13. Hydraulic Fracture: multiscale processes and moving

    E-Print Network [OSTI]

    Peirce, Anthony

    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

  14. FRACTURE TOUGHNESS OF WOOD AND WOOD COMPOSITES

    E-Print Network [OSTI]

    Nairn, John A.

    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

  15. Models for MetaVCeramic Interface Fracture

    E-Print Network [OSTI]

    Suo, Zhigang

    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

  16. FRACTURE IN DISORDERED BRITTLE MEDIA A Dissertation

    E-Print Network [OSTI]

    Sethna, James P.

    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

  17. Presented by Statistical Physics of Fracture

    E-Print Network [OSTI]

    Presented by Statistical Physics of Fracture: Recent Advances through High-Performance Computing) ­ Phys. Rev. E 71 (2005a, 2005b, 2005c); 73 (2006a, 2006b) ­ Adv. Phys. (2006); Int. J. Fracture (2006); Int. J. Fracture (2008a, 2008b) ­ J. Phys. D (2009); J. Chem. Phys. (2009); Phys. Rev. B (2009

  18. Image-Guided Fracture David Mould

    E-Print Network [OSTI]

    Mould, David

    Image-Guided Fracture David Mould Department of Computer Science University of Saskatchewan Abstract We present an image filter that transforms an input line drawing into an image of a fractured of an uncracked texture. Key words: Non-photorealistic rendering, fracture, tex- ture synthesis 1 Introduction Non

  19. Predicting Fracture Energies and Crack-Tip Fields of Soft Tough Materials

    E-Print Network [OSTI]

    Teng Zhang; Shaoting Lin; Hyunwoo Yuk; Xuanhe Zhao

    2015-06-13

    Soft materials including elastomers and gels are pervasive in biological systems and technological applications. Whereas it is known that intrinsic fracture energies of soft materials are relatively low, how the intrinsic fracture energy cooperates with mechanical dissipation in process zone to give high fracture toughness of soft materials is not well understood. In addition, it is still challenging to predict fracture energies and crack-tip strain fields of soft tough materials. Here, we report a scaling theory that accounts for synergistic effects of intrinsic fracture energies and dissipation on the toughening of soft materials. We then develop a coupled cohesive-zone and Mullins-effect model capable of quantitatively predicting fracture energies of soft tough materials and strain fields around crack tips in soft materials under large deformation. The theory and model are quantitatively validated by experiments on fracture of soft tough materials under large deformations. We further provide a general toughening diagram that can guide the design of new soft tough materials.

  20. Evaluations of the Irwin. beta. /sub Ic/ adjustment for small specimen fracture toughness data

    SciTech Connect (OSTI)

    Merkle, J.G.

    1983-01-01

    When small specimens are used to measure the cleavage fracture toughness of pressure vessel steels in the transition range of temperature, specimen thickness size effects and large amounts of data scatter are often observed. The size effects are manifested by an increase in the average value of fracture toughness with decreasing specimen thickness, eventually resulting in a change in fracture mode from cleavage to ductile tearing. It has been shown that a semiempirical adjustment for the interacting effects of specimen thickness, yield stress and toughness originally proposed by Irwin is capable of reducing the calculated values of toughness and data scatter to levels consistent with large specimen test data. This is true for dynamic as well as for static initiation toughness values. The nature of the size effect described by the Irwin ..beta../sub Ic/ equation is illustrated and specific cases are shown in which ..beta../sub Ic/ adjustment has eliminated size effects, for both static and dynamic fracture toughness data.

  1. Sensitivity analysis of fracture scattering

    E-Print Network [OSTI]

    Fang, Xinding

    We use 2D and 3D finite-difference modeling to numerically calculate the seismic response of a single finite fracture with a linear-slip boundary in a homogeneous elastic medium. We use a point explosive source and ignore ...

  2. Effective fracture geometry obtained with large water sand ratio 

    E-Print Network [OSTI]

    Kumar, Amrendra

    2009-05-15

    100000452 ............................... 58 4-21 Comparison of Power law Model with Traditional Model: Well 100000452 ........ 59 4-22 Effect of SRV on EUR........................................................................................ 60...

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

    SciTech Connect (OSTI)

    Not Available

    1981-06-01

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

  4. Geomechanical Simulation of Fluid-Driven Fractures

    SciTech Connect (OSTI)

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

    2012-11-30

    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.

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

    SciTech Connect (OSTI)

    R. L. Billingsley; V. Kuuskraa

    2006-03-31

    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.

  6. RESEARCH PROGRAM ON FRACTURED PETROLEUM RESERVOIRS

    SciTech Connect (OSTI)

    Abbas Firoozabadi

    2002-04-12

    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.

  7. Interaction between Injection Points during Hydraulic Fracturing

    E-Print Network [OSTI]

    Hals, Kjetil M D

    2012-01-01

    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.

  8. Stress-dependent permeability of fractured rock masses: A numerical study

    SciTech Connect (OSTI)

    Min, Ki-Bok; Rutqvist, J.; Tsang, Chin-Fu; Jing, Lanru

    2004-04-30

    We investigate the stress-dependent permeability issue in fractured rock masses considering the effects of nonlinear normal deformation and shear dilation of fractures using a two-dimensional distinct element method program, UDEC, based on a realistic discrete fracture network realization. A series of ''numerical'' experiments were conducted to calculate changes in the permeability of simulated fractured rock masses under various loading conditions. Numerical experiments were conducted in two ways: (1) increasing the overall stresses with a fixed ratio of horizontal to vertical stresses components; and (2) increasing the differential stresses (i.e., the difference between the horizontal and vertical stresses) while keeping the magnitude of vertical stress constant. These numerical experiments show that the permeability of fractured rocks decreases with increased stress magnitudes when the stress ratio is not large enough to cause shear dilation of fractures, whereas permeability increases with increased stress when the stress ratio is large enough. Permeability changes at low stress levels are more sensitive than at high stress levels due to the nonlinear fracture normal stress-displacement relation. Significant stress-induced channeling is observed as the shear dilation causes the concentration of fluid flow along connected shear fractures. Anisotropy of permeability emerges with the increase of differential stresses, and this anisotropy can become more prominent with the influence of shear dilation and localized flow paths. A set of empirical equations in closed-form, accounting for both normal closure and shear dilation of the fractures, is proposed to model the stress-dependent permeability. These equations prove to be in good agreement with the results obtained from our numerical experiments.

  9. Engineering approaches to the application of fracture toughness data in the nuclear industry

    SciTech Connect (OSTI)

    Merkle, J.G.

    1989-01-01

    The procedures for measuring the plane strain fracture toughness, K{sub Ic}, of metals were originally developed for relatively high yield strength materials, the toughnesses of which were not affected by strain rate. The application of these procedures to lower yield strength and higher toughness structural and pressure vessel steels have since revealed a perplexing combination of problems involving the effects of geometry, stable crack growth and strain rate on the measured values of toughness. Only the geometric problems were encountered in the development of the procedures for measuring K{sub Ic}. For fracture in the linear elastic range of the load-displacement curve, these problems were overcome by specifying specimen dimensions sufficiently large with respect to the plastic zone size at fracture. However, in the case of structural and pressure vessel steels, it is not always possible to test specimens large enough for fracture to occur prior to general yielding. Therefore, in these cases, the effects of large-scale yielding prior to fracture cannot be avoided, but since they presently have no analytical explanation they are being treated empirically. The problems of geometry and strain rate effects on toughness discussed herein are complex and difficult to solve. However, taking advantage of the improvements that have recently been made in the hardware and software available for performing three-dimensional elastic-plastic and viscoplastic stress analysis, it should be possible to significantly improve the analysis of small-specimen, elastic-plastic fracture toughness data.

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

    E-Print Network [OSTI]

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

    2014-10-07

    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 $G_I \\ll G_b$.

  11. Permeability Calculation in a Fracture Network - 12197

    SciTech Connect (OSTI)

    Lee, Cheo Kyung; Kim, Hyo Won [Handong Global University, 3 Namsong-ri, Heunghae-eub, Buk-gu, Pohang, Kyungbuk, 791-708 (Korea, Republic of); Yim, Sung Paal [Korea Atomic Energy Research Institute, Yusong, Daejon, 305-600 (Korea, Republic of)

    2012-07-01

    Laminar flow of a viscous fluid in the pore space of a saturated fractured rock medium is considered to calculate the effective permeability of the medium. The effective permeability is determined from the flow field which is calculated numerically by using the finite element method. The computation of permeability components is carried out with a few different discretizations for a number of fracture arrangements. Various features such as flow field in the fracture channels, the convergence of permeability, and the variation of permeability among different fracture networks are discussed. The longitudinal permeability in general appears greater than the transverse ones. The former shows minor variations with fracture arrangement whereas the latter appears to be more sensitive to the arrangement. From the calculations of the permeability in a rock medium with a fracture network (two parallel fractures aligned in the direction of 45-deg counterclockwise from the horizontal and two connecting fractures(narrowing, parallel and widening) the following conclusions are drawn. 1. The permeability of fractured medium not only depends on the primary orientation of the main fractures but also is noticeably influenced by the connecting fractures in the medium. 2. The transverse permeability (the permeability in the direction normal to the direction of the externally imposed macro-scale pressure gradient) is only a fraction of the longitudinal one, but is sensitive to the arrangement of the connecting fractures. 3. It is important to figure out the pattern of the fractures that connect (or cross) the main fractures for reliable calculation of the transverse permeability. (authors)

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

    E-Print Network [OSTI]

    Wang, J.S.Y.

    2013-01-01

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

  13. Chemically- and mechanically-mediated influences on the transport and mechanical characteristics of rock fractures

    SciTech Connect (OSTI)

    Min, K.-B.; Rutqvist, J.; Elsworth, D.

    2009-02-01

    A model is presented to represent changes in the mechanical and transport characteristics of fractured rock that result from coupled mechanical and chemical effects. The specific influence is the elevation of dissolution rates on contacting asperities, which results in a stress- and temperature-dependent permanent closure. A model representing this pressure-dissolution-like behavior is adapted to define the threshold and resulting response in terms of fundamental thermodynamic properties of a contacting fracture. These relations are incorporated in a stress-stiffening model of fracture closure to define the stress- and temperature-dependency of aperture loss and behavior during stress and temperature cycling. These models compare well with laboratory and field experiments, representing both decoupled isobaric and isothermal responses. The model was applied to explore the impact of these responses on heated structures in rock. The result showed a reduction in ultimate induced stresses over the case where chemical effects were not incorporated, with permanent reduction in final stresses after cooling to ambient conditions. Similarly, permeabilities may be lower than they were in the case where chemical effects were not considered, with a net reduction apparent even after cooling to ambient temperature. These heretofore-neglected effects may have a correspondingly significant impact on the performance of heated structures in rock, such as repositories for the containment of radioactive wastes.

  14. Topographic stress and rock fracture: a two-dimensional numerical model for arbitrary topography and preliminary comparison with borehole observations

    E-Print Network [OSTI]

    Perron, J. Taylor

    Theoretical calculations indicate that elastic stresses induced by surface topography may be large enough in some landscapes to fracture rocks, which in turn could influence slope stability, erosion rates, and bedrock ...

  15. 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]

    Pieve La Rosa, Andres Eduardo

    2011-08-08

    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...

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

    E-Print Network [OSTI]

    Nelson, J.T.

    2009-01-01

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

  17. Reservoir fracture mapping using microearthquakes: Austin chalk, Giddings field, TX and 76 field, Clinton Co., KY

    SciTech Connect (OSTI)

    Phillips, W.S.; Rutledge, J.T.; Gardner, T.L.; Fairbanks, T.D.; Miller, M.E.; Schuessler, B.K.

    1996-11-01

    Patterns of microearthquakes detected downhole defined fracture orientation and extent in the Austin chalk, Giddings field, TX and the 76 field, Clinton Co., KY. We collected over 480 and 770 microearthquakes during hydraulic stimulation at two sites in the Austin chalk, and over 3200 during primary production in Clinton Co. Data were of high enough quality that 20%, 31% and 53% of the events could be located, respectively. Reflected waves constrained microearthquakes to the stimulated depths at the base of the Austin chalk. In plan view, microearthquakes defined elongate fracture zones extending from the stimulation wells parallel to the regional fracture trend. However, widths of the stimulated zones differed by a factor of five between the two Austin chalk sites, indicating a large difference in the population of ancillary fractures. Post-stimulation production was much higher from the wider zone. At Clinton Co., microearthquakes defined low-angle, reverse-fault fracture zones above and below a producing zone. Associations with depleted production intervals indicated the mapped fractures had been previously drained. Drilling showed that the fractures currently contain brine. The seismic behavior was consistent with poroelastic models that predicted slight increases in compressive stress above and below the drained volume.

  18. Lynx: A High-Resolution Synthetic Aperture Radar

    SciTech Connect (OSTI)

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

    1999-03-08

    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.

  19. Impact of High-Order Multipole Errors in the NSLS-II Quadrupoles and Sectupoles on Dynamic and Momentum Aperture

    SciTech Connect (OSTI)

    Nash,B.; Guo, W.

    2009-05-04

    Successful operation of NSLS-II requires sufficient dynamic aperture for injection, as well as momentum aperture for Touschek lifetime. We explore the dependence of momentum and dynamic aperture on higher-order multipole field errors in the quadrupoles and sextupoles. We add random and systematic multipole errors to the quadrupoles and sextupoles and compute the effect on dynamic aperture. We find that the strongest effect is at negative momentum, due to larger closed orbit excursions. Adding all the errors based on the NSLS-II specifications, we find adequate dynamic and momentum aperture.

  20. Apparatus and method for monitoring underground fracturing

    DOE Patents [OSTI]

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

    1999-08-10

    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.

  1. Apparatus and method for monitoring underground fracturing

    DOE Patents [OSTI]

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

    1999-08-10

    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.

  2. On the multiscale origins of fracture resistance in human bone and its biological degradation

    SciTech Connect (OSTI)

    Zimmermann, Elizabeth A.; Barth, Holly D.; Ritchie, Robert O.

    2012-03-09

    Akin to other mineralized tissues, human cortical bone can resist deformation and fracture due to the nature of its hierarchical structure, which spans the molecular to macroscopic length-scales. Deformation at the smallest scales, mainly through the composite action of the mineral and collagen, contributes to bone?s strength or intrinsic fracture resistance, while crack-tip shielding mechanisms active on the microstructural scale contribute to the extrinsic fracture resistance once cracking begins. The efficiency with which these structural features can resist fracture at both small and large length-scales becomes severely degraded with such factors as aging, irradiation and disease. Indeed aging and irradiation can cause changes to the cross-link profile at fibrillar length-scales as well as changes at the three orders of magnitude larger scale of the osteonal structures, both of which combine to inhibit the bone's overall resistance to the initiation and growth of cracks.

  3. Thermal Fracturing of Geothermal Wells and the Effects of Borehole Orientation

    E-Print Network [OSTI]

    Hals, Kjetil M D

    2012-01-01

    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...

  4. Aperture Photometry and Transit Light Curve Analysis D. Cohen and E. Jensen

    E-Print Network [OSTI]

    Cohen, David

    Aperture Photometry and Transit Light Curve Analysis D. Cohen and E the Relative Photometry2 instructions. Context This follows on to the WASP-11. You can load them into an image stack in AIJ and open up the photometry

  5. New target detector based on geometrical perturbation filters for polarimetric Synthetic Aperture Radar (POL-SAR) 

    E-Print Network [OSTI]

    Marino, Armando

    2010-01-01

    Synthetic Aperture Radar (SAR) is an active microwave remote sensing system able to acquire high resolution images of the scattering behaviour of an observed scene. The contribution of SAR polarimetry (POLSAR) in detection ...

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

    E-Print Network [OSTI]

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

    2001-10-01

    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...

  7. Are Carotid Stent Fractures Clinically Significant?

    SciTech Connect (OSTI)

    Garcia-Toca, Manuel; Rodriguez, Heron E.; Naughton, Peter A. [Northwestern University Feinberg School of Medicine, Division of Vascular Surgery (United States); Keeling, Aiofee [Northwestern University Feinberg School of Medicine, Department of Radiology (United States); Phade, Sachin V.; Morasch, Mark D.; Kibbe, Melina R.; Eskandari, Mark K., E-mail: meskanda@nmh.org [Northwestern University Feinberg School of Medicine, Division of Vascular Surgery (United States)

    2012-04-15

    Purpose: Late stent fatigue is a known complication after carotid artery stenting (CAS) for cervical carotid occlusive disease. The purpose of this study was to determine the prevalence and clinical significance of carotid stent fractures. Materials and Methods: A single-center retrospective review of 253 carotid bifurcation lesions treated with CAS and mechanical embolic protection from April 2001 to December 2009 was performed. Stent integrity was analyzed by two independent observers using multiplanar cervical plain radiographs with fractures classified into the following types: type I = single strut fracture; type II = multiple strut fractures; type III = transverse fracture; and type IV = transverse fracture with dislocation. Mean follow-up was 32 months. Results: Follow-up imaging was completed on 106 self-expanding nitinol stents (26 closed-cell and 80 open-cell stents). Eight fractures (7.5%) were detected (type I n = 1, type II n = 6, and type III n = 1). Seven fractures were found in open-cell stents (Precise n = 3, ViVEXX n = 2, and Acculink n = 2), and 1 fracture was found in a closed-cell stent (Xact n = 1) (p = 0.67). Only a previous history of external beam neck irradiation was associated with fractures (p = 0.048). No associated clinical sequelae were observed among the patients with fractures, and only 1 patient had an associated significant restenosis ({>=}80%) requiring reintervention. Conclusions: Late stent fatigue after CAS is an uncommon event and rarely clinically relevant. Although cell design does not appear to influence the occurrence of fractures, lesion characteristics may be associated risk factors.

  8. Effects of fracturing fluid recovery upon well performance and ultimate recovery of hydraulically fractured gas wells 

    E-Print Network [OSTI]

    Berthelot, Jan Marie

    1990-01-01

    EFFECTS OF FRACTURING FLUID RECOVERY UPON WELL PERFORMANCE AND ULTIMATE RECOVERY OF HYDRAULICALLY FRACTURED GAS WELLS A Thesis IAN MARIE BERTHELOT Submitted to the Office of Graduate Studies of Texas AdtM University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE May 1990 Major Subject: Petroleum Engineering EFFECTS OF FRACTURING FLUID RECOVERY UPON WELL PERFORMANCE AND ULTIMATE RECOVERY OF HYDRAULICALLY FRACTURED GAS WELLS by JAN MARIE BERTIIELOT Appmved...

  9. Multipinhole collimator with 20 apertures for a brain SPECT application

    SciTech Connect (OSTI)

    Lee, Tzu-Cheng; Ellin, Justin R.; Shrestha, Uttam; Seo, Youngho; Huang, Qiu; Gullberg, Grant T.

    2014-11-01

    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.

  10. Method of fracturing a geological formation

    DOE Patents [OSTI]

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

    1990-01-01

    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.

  11. Hydraulic Fracturing Poster | Department of Energy

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

    Educational poster graphically displaying the key components of hydraulic fracturing. Teachers: If you would like hard copies of this poster sent to you, please contact the FE...

  12. A compendium of fracture flow models, 1994

    SciTech Connect (OSTI)

    Diodato, D.M.

    1994-11-01

    The report is designed to be used as a decision-making aid for individuals who need to simulate fluid flow in fractured porous media. Fracture flow codes of varying capability in the public and private domain were identified in a survey of government, academia, and industry. The selection and use of an appropriate code requires conceptualization of the geology, physics, and chemistry (for transport) of the fracture flow problem to be solved. Conceptual models that have been invoked to describe fluid flow in fractured porous media include explicit discrete fracture, dual continuum (porosity and/or permeability), discrete fracture network, multiple interacting continua, multipermeability/multiporosity, and single equivalent continuum. The explicit discrete-fracture model is a ``near-field`` representation, the single equivalent continuum model is a ``far-field`` representation, and the dual-continuum model is intermediate to those end members. Of these, the dual-continuum model is the most widely employed. The concept of multiple interacting continua has been applied in a limited number of examples. Multipermeability/multiporosity provides a unified conceptual model. The ability to accurately describe fracture flow phenomena will continue to improve as a result of advances in fracture flow research and computing technology. This improvement will result in enhanced capability to protect the public environment, safety, and health.

  13. Regional Analysis And Characterization Of Fractured Aquifers...

    Open Energy Info (EERE)

    Regional Analysis And Characterization Of Fractured Aquifers In The Virginia Blue Ridge And Piedmont Provinces Jump to: navigation, search OpenEI Reference LibraryAdd to library...

  14. Structural Settings Of Hydrothermal Outflow- Fracture Permeability...

    Open Energy Info (EERE)

    long-lived hydrothermal flow despite potential clogging of fractures due to mineral precipitation. As fault systems evolve, propagation, interaction, and linkage of fault segments...

  15. Absolute Calibration of a Large-diameter Light Source

    E-Print Network [OSTI]

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

    2013-01-01

    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.

  16. Characterization of EGS Fracture Network Lifecycles

    SciTech Connect (OSTI)

    Gillian R. Foulger

    2008-03-31

    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

  17. Efficient Double-Beam Characterization for Fractured Reservoir

    E-Print Network [OSTI]

    Zheng, Yingcai

    We proposed an efficient target-oriented method to characterize seismic properties of fractured reservoirs: the spacing between fractures and the fracture orientation. Based on the diffraction theory, the scattered wave ...

  18. Characterization of dipping fractures in transversely isotropic background

    E-Print Network [OSTI]

    Tsvankin, Ilya

    Characterization of dipping fractures in transversely isotropic background Vladimir Grechka incidence becomes dependent on fracture infill (saturation). A complete medium-characterization procedure for the vertical and NMO velocities. Keywords.--fracture characterization, azimuthal anisotropy, multicomponent

  19. Incorporating Rigorous Height Determination into Unified Fracture Design 

    E-Print Network [OSTI]

    Pitakbunkate, Termpan

    2010-10-12

    Hydraulic fracturing plays an important role in increasing production rate in tight reservoirs. The performance of the reservoir after fracturing can be observed from the productivity index. This parameter is dependent on the fracture geometry...

  20. A PKN Hydraulic Fracture Model Study and Formation Permeability Determination 

    E-Print Network [OSTI]

    Xiang, Jing

    2012-02-14

    Hydraulic fracturing is an important method used to enhance the recovery of oil and gas from reservoirs, especially for low permeability formations. The distribution of pressure in fractures and fracture geometry are needed to design conventional...

  1. FINITE FRACTURE MECHANICS OF MATRIX MICROCRACKING IN COMPOSITES

    E-Print Network [OSTI]

    Nairn, John A.

    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

  2. Seismic characterization of fractured reservoirs using 3D double beams

    E-Print Network [OSTI]

    Zheng, Yingcai

    2012-01-01

    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 ...

  3. Ductile fracture modeling : theory, experimental investigation and numerical verification

    E-Print Network [OSTI]

    Xue, Liang, 1973-

    2007-01-01

    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 ...

  4. Brittle and ductile fracture of semiconductor nanowires --molecular dynamics simulations

    E-Print Network [OSTI]

    Cai, Wei

    Brittle and ductile fracture of semiconductor nanowires -- molecular dynamics simulations Keonwook November 9, 2006 Abstract Fracture of silicon and germanium nanowires in tension at room temperature potentials predict brittle fracture initiated by crack nucleation from the surface, most potentials predict

  5. Stochastic multiscale models for fracture analysis of functionally graded materials

    E-Print Network [OSTI]

    Rahman, Sharif

    Stochastic multiscale models for fracture analysis of functionally graded materials Arindam three multiscale models, including sequential, invasive, and concurrent models, for fracture analysis methods for fracture reliability analysis. The par- ticle volume fractions, defined by a generic

  6. UNIVERSITY OF CALGARY Modeling Fracture Formation on Growing Surfaces

    E-Print Network [OSTI]

    Prusinkiewicz, Przemyslaw

    UNIVERSITY OF CALGARY Modeling Fracture Formation on Growing Surfaces by Pavol Federl A THESIS Fracture Formation on Growing Surfaces" submitted by Pavol Federl in partial fulfillment This thesis describes a framework for modeling fracture formation on differentially growing, bi- layered

  7. The relationship between constraint and ductile fracture initiation as defined by micromechanical analyses

    SciTech Connect (OSTI)

    Panontin, T.L.; Sheppard, S.D.

    1995-12-31

    The overall objective of this study is to provide a proven methodology to allow the transfer of ductile fracture initiation properties measured in standard laboratory specimens to large, complex, flawed structures. A significant part of this work involved specifically addressing the effects of constrain on transferability under large scale yielding conditions. The approach taken was to quantify constrain effects through micromechanical fracture models coupled with finite element generated crack tip stress-strain fields to identify the local condition corresponding to fracture initiation. Detailed finite element models predicted the influence of specimen geometry, loading mode, and material flow properties on the crack tip fields. The ability of two local, ductile fracture models (the Rice and Tracey void growth model (VGM) and the stress-modified, critical strain (SMCS) criterion of Mackenzie et al. and Hancock and Cowling) to predict fracture initiation were investigated. Predictions were made using experimentally verified, two- and three-dimensional, finite strain, large deformation, finite element analyses. Two, high toughness pressure vessel steels were investigated: A516 Gr70, a ferritic, carbon-manganese mild steel demonstrating high hardening behavior, and HY-80, a martensitic, high strength low alloy (HSLA) steel possessing medium hardening ability. Experimental verification of the ductile fracture initiation predictions was performed in a variety of crack geometries possessing a range of a/w ratios from 0.15 to 0.70 and experiencing a range of load conditions from three point bending to nearly pure tension. The predicted constrain dependence of global ductile fracture parameters in the two materials is shown.

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

    E-Print Network [OSTI]

    Tao, Qingfeng

    2010-07-14

    Fractures are the main flow channels in naturally fractured reservoirs. Therefore the fracture permeability is a critical parameter to production optimization and reservoir management. Fluid pressure reduction caused by production induces...

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

    E-Print Network [OSTI]

    Rutqvist, J.

    2011-01-01

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

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

    E-Print Network [OSTI]

    Cotte, F.P.

    2012-01-01

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

  11. Detecting Fractures Using Technology at High Temperatures and...

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

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

  12. Images of Fracture Sustainability Test on Stripa Granite

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Tim Kneafsey

    2014-05-11

    Images of the Stripa Granite core before and after the fracture sustainability test. Photos of fracture faces of Stripa Granite core.

  13. Predicting fracture in micron-scale polycrystalline silicon MEMS...

    Office of Scientific and Technical Information (OSTI)

    Predicting fracture in micron-scale polycrystalline silicon MEMS structures. Citation Details In-Document Search Title: Predicting fracture in micron-scale polycrystalline silicon...

  14. Final Report Multiazimuth Seismic Diffraction Imaging for Fracture...

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

    ...67 Figure 2.6 Fracture path and required pressure for critical growth, SH0.1...69 Figure 2.7 Fracture path and required...

  15. Images of Fracture Sustainability Test on Stripa Granite

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Tim Kneafsey

    Images of the Stripa Granite core before and after the fracture sustainability test. Photos of fracture faces of Stripa Granite core.

  16. Integration of well test analysis into naturally fractured reservoir simulation 

    E-Print Network [OSTI]

    Perez Garcia, Laura Elena

    2006-04-12

    Naturally fractured reservoirs (NFR) represent an important percentage of the worldwide hydrocarbon reserves and production. Reservoir simulation is a fundamental technique in characterizing this type of reservoir. Fracture ...

  17. Fractured rock stress-permeability relationships from in situ...

    Office of Scientific and Technical Information (OSTI)

    Fractured rock stress-permeability relationships from in situ data and effects of temperature and chemical-mechanical couplings Citation Details In-Document Search Title: Fractured...

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

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

    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....

  19. Elastic properties of saturated porous rocks with aligned fractures

    E-Print Network [OSTI]

    2003-12-02

    Elastic properties of fluid saturated porous media with aligned fractures can be studied using the ...... that are in hydraulic equilibrium with the fractures, the.

  20. Irradiation Effects on Human Cortical Bone Fracture Behavior

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

    Fracture Behavior Print Human bone is strong but still fallible. To better predict fracturing in bone, researchers need a mechanistic framework to understand the changes taking...

  1. Thermal-hydrologic-mechanical behavior of single fractures in...

    Office of Scientific and Technical Information (OSTI)

    Thermal-hydrologic-mechanical behavior of single fractures in EGS reservoirs Citation Details In-Document Search Title: Thermal-hydrologic-mechanical behavior of single fractures...

  2. Northwestern University Technological Institute Tight Shale Gas-Hydraulic Fracturing

    E-Print Network [OSTI]

    Guo, Dongning

    Northwestern University Technological Institute Tight Shale Gas-Hydraulic Fracturing Seminar Series fracturing of horizontal wells is priceless Sidney Green, London Shale Gas Summit, 2010 #12;Vertical Well

  3. 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...

  4. Detection and Characterization of Natural and Induced Fractures...

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

    Characterization of Natural and Induced Fractures for the Development of Enhanced Geothermal Systems Detection and Characterization of Natural and Induced Fractures for the...

  5. 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...

  6. Three-dimensional Modeling of Fracture Clusters in Geeothermal...

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

    Geeothermal Reservoirs Three-dimensional Modeling of Fracture Clusters in Geeothermal Reservoirs Three-dimensional Modeling of Fracture Clusters in Geeothermal Reservoirs...

  7. Fracture of solid state laser slabs

    SciTech Connect (OSTI)

    Marion, J.E.

    1986-07-01

    Fracture due to thermal stress limits the power output potential of modern, high average power slab lasers. Here the criteria for slab fracture and the nature of the surface flaws which constitute the strength-controlling defects are reviewed. Specific fracture data for gadolinium scandium gallium garnet and LHG-5 phosphate glass with different surface finishes are evaluated in the context of assigning appropriate slab operating parameters using Wiebull statistics. These examples illustrate both the danger of design using brittle components without adequate fracture testing, and the inadequacy of design methods which use a fixed safety factor, for this class of materials. Further consideration reveals that operation of slab lasers in contact with an aqueous coolant may lead to strength degradation with time. Finally, the evolution of the failure process in which a characteristic midplane crack forms is outlined, and the pertinent parameters for avoiding slab fracture are identified.

  8. Hydraulic fracturing slurry transport in horizontal pipes

    SciTech Connect (OSTI)

    Shah, S.N.; Lord, D.L. (Halliburton Services (US))

    1990-09-01

    Horizontal-well activity has increased throughout the industry in the past few years. To design a successful hydraulic fracturing treatment for horizontal wells, accurate information on the transport properties of slurry in horizontal pipe is required. Limited information exists that can be used to estimate critical deposition and resuspension velocities when proppants are transported in horizontal wells with non-Newtonian fracturing gels. This paper presents a study of transport properties of various hydraulic fracturing slurries in horizontal pipes. Flow data are gathered in three transparent horizontal pipes with different diameters. Linear and crosslinked fracturing gels were studied, and the effects of variables--e.g., pipe size; polymer-gelling-agent concentration; fluid rheological properties; crosslinking effects; proppant size, density, and concentrations; fluid density; and slurry pump rate--on critical deposition and resuspension velocities were investigated. Also, equations to estimate the critical deposition and resuspension velocities of fracturing gels are provided.

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

    SciTech Connect (OSTI)

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

    1999-01-01

    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.

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

    SciTech Connect (OSTI)

    Riha, B; Warren Hyde, W; Richard Hall , R

    2008-03-12

    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.

  11. Self-potential observations during hydraulic fracturing

    SciTech Connect (OSTI)

    Moore, Jeffrey R.; Glaser, Steven D.

    2007-09-13

    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.

  12. Polarization measurement and vertical aperture optimization for obtaining circularly polarized bend-magnet radiation

    SciTech Connect (OSTI)

    Kortright, J.; Rice, M.; Hussain, Z.; Padmore, H.; Adamson, A.; Huff, W.; Young, A.; Moler, E.; Kellar, S.; Ynzunza, R.; Palomares, F.; Daimon, H.; Tober, E.; Fadley, C. [Center for X-Ray Optics, Advanced Light Source, Chemical Sciences Division, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)] [Center for X-Ray Optics, Advanced Light Source, Chemical Sciences Division, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); [Physics Department, University of California-Davis, Davis, CA 95616 (United States); [Department of Material Physics, Osaka University, Osaka (Japan)

    1996-09-01

    Using multilayer linear polarizers, we have characterized the polarization state of radiation from bend-magnet beamline 9.3.2 at the Advanced Light Source as a function of vertical opening angle at photon energies of 367 and 722 eV. Both a fine slit and a coarse semi-aperture were stepped across the beam to accept different portions of the vertical radiation fan. Polarimetry yields the degree of linear polarization directly and the degree of circular polarization indirectly assuming an immeasurably small amount of unpolarized radiation based on the close agreement of the theoretical and experimental results for linear polarization. The results are in good agreement with theoretical calculations, with departures from theory resulting from uncertainty in the effective aperture of the measured beam. The narrow 0.037-mrad aperture on the orbit plane transmits a beam whose degree of linear polarization exceeds 0.99 at these energies. The wide semi-aperture blocking the beam from above and below transmits a beam with a maximum figure of merit, given by the square root of flux times the degree of circular polarization, when the aperture edge is on the orbit plane thus blocking only half of the total available flux. {copyright} {ital 1996 American Institute of Physics.}

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

    SciTech Connect (OSTI)

    Petti, Jason P.; Kalan, Robert J.

    2011-12-01

    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.

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

    SciTech Connect (OSTI)

    Unknown

    1999-12-01

    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.

  15. Spectral light separator based on deep-subwavelength resonant apertures in a metallic film

    SciTech Connect (OSTI)

    Büyükalp, Yasin; Catrysse, Peter B. Shin, Wonseok; Fan, Shanhui

    2014-07-07

    We propose to funnel, select, and collect light spectrally by exploiting the unique properties of deep-subwavelength resonant apertures in a metallic film. In our approach, each aperture has an electromagnetic cross section that is much larger than its physical size while the frequency of the collected light is controlled by its height through the Fabry-Pérot resonance mechanism. The electromagnetic crosstalk between apertures remains low despite physical separations in the deep-subwavelength range. The resulting device enables an extremely efficient, subwavelength way to decompose light into its spectral components without the loss of photons and spatial coregistration errors. As a specific example, we show a subwavelength-size structure with three deep-subwavelength slits in a metallic film designed to operate in the mid-wave infrared range between 3 and 5.5??m.

  16. A simple technique to reduce evaporation of crystallization droplets by using plate lids with apertures for adding liquids

    SciTech Connect (OSTI)

    Zipper, Lauren E.; Aristide, Xavier; Bishop, Dylan P.; Joshi, Ishita; Kharzeev, Julia; Patel, Krishna B.; Santiago, Brianna M.; Joshi, Karan; Dorsinvil, Kahille; Sweet, Robert M.; Soares, Alexei S.

    2014-11-28

    This article describes the use of evaporation control lids that are fitted to crystallization plates to improve the reproducibility of trials using as little as 5 nl. The plate lids contain apertures which are large enough for the transfer of protein containing droplets, but small enough to greatly reduce the rate of evaporation during the time needed to prepare the plate. A method is described for using plate lids to reduce evaporation in low-volume vapor-diffusion crystallization experiments. The plate lids contain apertures through which the protein and precipitants were added to different crystallization microplates (the reservoir was filled before fitting the lids). Plate lids were designed for each of these commonly used crystallization microplates. This system minimizes the dehydration of crystallization droplets containing just a few nanolitres of protein and precipitant, and results in more reproducible diffraction from the crystals. For each lid design, changes in the weight of the plates were used to deduce the rate of evaporation under different conditions of temperature, air movement, droplet size and precipitant. For comparison, the state of dehydration was also visually assessed throughout the experiment. Finally, X-ray diffraction methods were used to compare the diffraction of protein crystals that were conventionally prepared against those that were prepared on plates with plate lids. The measurements revealed that the plate lids reduced the rate of evaporation by 63–82%. Crystals grown in 5 nl drops that were set up with plate lids diffracted to higher resolution than similar crystals from drops that were set up without plate lids. The results demonstrate that plate lids can be instrumental for improving few-nanolitre crystallizations.

  17. Research paper Thermalmechanical modeling of cooling history and fracture development

    E-Print Network [OSTI]

    Kattenhorn, Simon

    from cooling fracture patterns in field examples on the eastern Snake River Plain, Idaho, and highlight

  18. 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.

  19. Calibration of hydraulic and tracer tests in fractured media

    E-Print Network [OSTI]

    Politècnica de Catalunya, Universitat

    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

  20. Reply to Davies: Hydraulic fracturing remains a possible mechanism for

    E-Print Network [OSTI]

    Jackson, Robert B.

    LETTER Reply to Davies: Hydraulic fracturing remains a possible mechanism for observed methane mechanisms were leaky gas well casings and the possibility that hydraulic fracturing might generate new- knowledged the possibility of hydraulic fracturing playing a role. Is it possible that hydraulic fracturing

  1. Statistical RKR Modeling of Mixed-Mode Fracture

    E-Print Network [OSTI]

    Ritchie, Robert

    Statistical RKR Modeling of Mixed-Mode Fracture in a Brittle Functionally Graded Material by T. L-calibration for fracture mechanics sample with modulus gradient ·Calculate effect of gradient slope on ·predicted fracture fK x II ijII I ijI ij 2 )( 2 )( )exp( #12;·The RKR fracture model correlates the onset

  2. International Journal of Fracture volume 5, number 2, 167181 (2009)

    E-Print Network [OSTI]

    Nairn, John A.

    2009-01-01

    International Journal of Fracture volume 5, number 2, 167­181 (2009) Analytical and Numerical March 2009 Abstract At the onset of fracture in materials with process zones, the fracture resis- tance with bridging zones. The simulation method includes pure fracture mechanics and pure cohesive zone models

  3. Continuous Aperture Phased MIMO: Basic Theory and Applications

    E-Print Network [OSTI]

    Sayeed, Akbar M.

    behind CAP-MIMO and the potential capacity/power gains afforded by it. We also highlight potential--Given the proliferation of wireless communication devices, the need for increased power and bandwidth efficiency for addressing these challenges: mm-wave systems (60-100GHz) that afford large bandwidths, and multi

  4. Effect of beam limiting aperture and collector potential on multi-element focused ion beams

    SciTech Connect (OSTI)

    Paul, Samit; Chowdhury, Abhishek; Bhattacharjee, Sudeep [Department of Physics, Indian Institute of Technology, Kanpur, Uttar Pradesh (India)

    2012-02-15

    A compact microwave driven plasma based multi-element focused ion beam system has been developed. In the present work, the effect of reduced beam limiter (BL) aperture on the focused ion beam parameters, such as current and spot size, and a method of controlling beam energy independently by introducing a biased collector at focal point (FP) are investigated. It is found that the location of FP does not change due to the reduction of BL aperture. The location of FP and beam size are found to be weakly dependent on the collector potential in the range from -8 kV to -18 kV.

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

    E-Print Network [OSTI]

    Ritchie, Robert

    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

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

    E-Print Network [OSTI]

    Collins, Gary S.

    · 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

  7. Predicting hip fracture type with cortical bone mapping (CBM) in the Osteoporotic Fractures in Men (MrOS) study

    E-Print Network [OSTI]

    Drummond, Tom

    Predicting hip fracture type with cortical bone mapping (CBM) in the Osteoporotic Fractures in Men, for the Osteoporotic Fractures in Men (MrOS) study CUED/F-INFENG/TR 695 January 2015 Cambridge University Engineering;1 Abstract Hip fracture risk is known to be related to material properties of the proximal femur, but prospec

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

    E-Print Network [OSTI]

    Forbis, Robert E.

    2014-01-01

    lic fracturing, or “fracking,” where chemically treatedreduced by the advent of fracking and directional drilling.That began to be developed, fracking is fundamental to that,

  9. Fractured: Experts examine the contentious issue of hydraulic fracturing water use 

    E-Print Network [OSTI]

    Wythe, Kathy

    2013-01-01

    Story by Kathy Wythe FRACTURED Experts examine the contentious issue of hydraulic fracturing water use In a state where oil and gas are king, and water is? in words commonly a?ributed to Mark Twain? ?for ?ghting over,? an unconventional method... that uses water to extract oil and gas from Texas? underground ?elds is causing passionate debate. ?is method?hydraulic fracturing?uses water and other ?uids under pressure to fracture or crack shale rock, releasing oil and gas from the rock. Combined...

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

    SciTech Connect (OSTI)

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

    2012-01-01

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

  11. Multiphase flow in fractured porous media

    SciTech Connect (OSTI)

    Firoozabadi, A.

    1995-02-01

    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.

  12. Anomalous transport through porous and fractured media

    E-Print Network [OSTI]

    Kang, Peter Kyungchul

    2014-01-01

    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 ...

  13. Fracture of surface cracks loaded in bending

    SciTech Connect (OSTI)

    Chao, Y.J.; Reuter, W.G.

    1997-12-31

    Theoretical background of the constraint effect in brittle fracture of solids is reviewed. Fracture test data from D6-aC, a high strength steel, using three-point-bend (SE(B)) specimens and surface cracked plate (SC(B)) specimens under bending are presented. It is shown that the SE(B) data has an elevated fracture toughness for increasing a/W, i.e., a crack geometry with a larger T/K corresponds to a higher K{sub c} which is consistent with the theoretical prediction. The fundamental fracture properties, i.e., the critical strain and the critical distance, determined from the SE(B) test data are then applied to the interpretation and prediction of the SC(B) test data. Reasonable agreement is achieved for the crack growth initiation site and the load.

  14. Freeze fracturing of elastic porous media

    E-Print Network [OSTI]

    Vlahou, Ioanna

    2012-06-12

    is the growth of ice lenses in saturated cohesive soils. I present results for typical soil parameters and find good agreement between our theory and experimental observations of growth rates and minimum undercoolings required for fracturing....

  15. Universal asymptotic umbrella for hydraulic fracture modeling

    E-Print Network [OSTI]

    Linkov, Aleksandr M

    2014-01-01

    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.

  16. Geomechanical review of hydraulic fracturing technology

    E-Print Network [OSTI]

    Arop, Julius Bankong

    2013-01-01

    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 ...

  17. Poroelastic response of orthotropic fractured porous media

    SciTech Connect (OSTI)

    Berryman, J.G.

    2010-12-01

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

  18. Accounting for Remaining Injected Fracturing Fluid 

    E-Print Network [OSTI]

    Zhang, Yannan

    2013-12-06

    wells: liquid film movement along the walls of the pipe, and liquid droplets associated with the high velocity gas. The critical condition to transport liquids from gas wells is the high enough gas velocity to transport the largest drops... critical value, the critical-gas velocity changes with the concentration. Kuru et al. (2013) suggested that non-recovered water can also accumulate in the fractures. The height of hydraulic fractures in horizontal wells is usually from tens to hundreds...

  19. Dynamic Fracture Toughness of Polymer Composites 

    E-Print Network [OSTI]

    Harmeet Kaur

    2012-02-14

    to fully charac- terize material properties before using them for applications in critical industries, like that of defense or transport. In this project, the focus is on determining dy- namic fracture toughness property of ber reinforced polymer... : : : : 33 III Wave speeds and traveling times making a particular angle to laminate ber direction : : : : : : : : : : : : : : : : : : : : : : : : : 37 IV Mode-I quasi-static fracture toughness values (KIC) : : : : : : : : : : 45 V Mode-II quasi...

  20. An experimental validation of a theoretical Charpy-fracture toughness correlation 

    E-Print Network [OSTI]

    Zapata, John Edgar

    1988-01-01

    that the crack front length B or THICKNESS FIG. 5 ? Fracture toughness variations with thickness. specimen thickness is large enough for the material surrounding the czack front to be restrained to plane strain by the material that is removed from the crack..., manual shielded metal-arc welded ABS grade EH36 steel using a 8018 ? C3 electrode [43]. Data for two different heats of SA533B ? 1 base metal were obtained from the Elec- tric Power Research Institute fracture toughness data, base[44]. Wellman, et al...

  1. VAPHOT -A Package for Precision Differential Aperture Photometry HANS J. DEEG1,2, LAURANCE R. DOYLE3

    E-Print Network [OSTI]

    Deeg, Hans-Jörg

    VAPHOT - A Package for Precision Differential Aperture Photometry HANS J. DEEG1,2, LAURANCE R radius, diameter and 'size' is clarified Abstract The aperture photometry package `vaphot' was developed to perform reliable and precise time-series photometry of uncrowded fields. This package works within

  2. The Small and Moderate Aperture Research Telescope System A Proposal to Operate the Small Telescopes at CTIO

    E-Print Network [OSTI]

    Walter, Frederick M.

    The Small and Moderate Aperture Research Telescope System (SMARTS) A Proposal to Operate the Small Observatory #12; The Small and Moderate Aperture Research Telescope System (SMARTS) ABSTRACT We propose to operate four telescopes located at the Cerro Tololo Interamerican Observatory (CTIO) for the period from

  3. Active control of passive acoustic fields: Passive synthetic apertureDoppler beamforming with data from an autonomous

    E-Print Network [OSTI]

    Smith, Jerome A.

    Active control of passive acoustic fields: Passive synthetic apertureÕDoppler beamforming with data without the use of an active source under control by the receiver. In this passive case, the properties interest. Passive synthetic aperture sonar has no ana- log in the radar community. In contrast

  4. Failing softly: A fracture theory of highly-deformable materials

    E-Print Network [OSTI]

    Tamar Goldman Boué; Roi Harpaz; Jay Fineberg; Eran Bouchbinder

    2015-03-24

    Highly-deformable materials, from synthetic hydrogels to biological tissues, are becoming increasingly important from both fundamental and practical perspectives. Their mechanical behaviors, in particular the dynamics of crack propagation during failure, are not yet fully understood. Here we propose a theoretical framework for the dynamic fracture of highly-deformable materials, in which the effects of a dynamic crack are treated with respect to the nonlinearly deformed (pre-stressed/strained), non-cracked, state of the material. Within this framework, we derive analytic and semi-analytic solutions for the near-tip deformation fields and energy release rates of dynamic cracks propagating in incompressible neo-Hookean solids under biaxial and uniaxial loading. We show that moderately large pre-stressing has a marked effect on the stress fields surrounding a crack's tip. We verify these predictions by performing extensive experiments on the fracture of soft brittle elastomers over a range of loading levels and propagation velocities, showing that the newly developed framework offers significantly better approximations to the measurements than standard approaches at moderately large levels of external loadings and high propagation velocities. This framework should be relevant to the failure analysis of soft and tough, yet brittle, materials.

  5. Rock Joint Surfaces Measurement and Analysis of Aperture Distribution under Different Normal and Shear Loading Using GIS

    E-Print Network [OSTI]

    Sharifzadeh, Mostafa; Esaki, Tetsuro

    2009-01-01

    Geometry of the rock joint is a governing factor for joint mechanical and hydraulic behavior. A new method of evaluating aperture distribution based on measurement of joint surfaces and three dimensional characteristics of each surface is developed. Artificial joint of granite surfaces are measured,processed, analyzed and three dimensional approaches are carried out for surface characterization. Parameters such as asperity's heights, slope angles, and aspects distribution at micro scale,local concentration of elements and their spatial localization at local scale are determined by Geographic Information System (GIS). Changes of aperture distribution at different normal stresses and various shear displacements are visualized and interpreted. Increasing normal load causes negative changes in aperture frequency distribution which indicates high joint matching. However, increasing shear displacement causes a rapid increase in the aperture and positive changes in the aperture frequency distribution which could be ...

  6. Phase retrieval with the transport-of-intensity equation in an arbitrarily-shaped aperture by iterative discrete cosine transforms

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

    Huang, Lei; Zuo, Chao; Idir, Mourad; Qu, Weijuan; Asundi, Anand

    2015-04-21

    A novel transport-of-intensity equation (TIE) based phase retrieval method is proposed with putting an arbitrarily-shaped aperture into the optical wavefield. In this arbitrarily-shaped aperture, the TIE can be solved under non-uniform illuminations and even non-homogeneous boundary conditions by iterative discrete cosine transforms with a phase compensation mechanism. Simulation with arbitrary phase, arbitrary aperture shape, and non-uniform intensity distribution verifies the effective compensation and high accuracy of the proposed method. Experiment is also carried out to check the feasibility of the proposed method in real measurement. Comparing to the existing methods, the proposed method is applicable for any types of phasemore »distribution under non-uniform illumination and non-homogeneous boundary conditions within an arbitrarily-shaped aperture, which enables the technique of TIE with hard aperture become a more flexible phase retrieval tool in practical measurements.« less

  7. Technical Evaluation Report "ND2 Attenuation of the COS Bright Object Aperture"

    E-Print Network [OSTI]

    Colorado at Boulder, University of

    Technical Evaluation Report "ND2 Attenuation of the COS Bright Object Aperture" Date: 30 June 2000 Document Number: COS-11-0019 Revision: Initial Release Contract No.: NAS5-98043 CDRL No.: N/A Prepared By: J. Morse, COS Project Scientist, CU/CASA Date Reviewed By: J. Green, COS Principal Investigator, CU

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

    SciTech Connect (OSTI)

    Doerry, Armin Walter

    2012-05-01

    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.

  9. Seasonal subsidence and rebound in Las Vegas Valley, Nevada, observed by synthetic aperture radar interferometry

    E-Print Network [OSTI]

    Amelung, Falk

    Seasonal subsidence and rebound in Las Vegas Valley, Nevada, observed by synthetic aperture radar in the subsidence and rebound occurring over stressed aquifer systems, in conjunction with measurements, generally permanent aquifer system compaction and land subsidence at yearly and longer timescales, caused

  10. SYNTHETIC APERTURE INVERSION FOR NON-FLAT TOPOGRAPHY C. J. Nolan *

    E-Print Network [OSTI]

    Cheney, Margaret

    SYNTHETIC APERTURE INVERSION FOR NON-FLAT TOPOGRAPHY C. J. Nolan * , M. Cheney ** * Department topography is known but not necessarily flat. We consider two cases, corresponding to the degree and the topography to avoid artifacts. We show that the algorithm correctly reproduces certain features of the scene

  11. Aperture Test for Internal Target Operation in the JLAB High-current ERL

    SciTech Connect (OSTI)

    Zhang, Shukui

    2013-06-01

    A high current beam transmission test has been successfully completed at the JLAB FEL Facility, culminating in very low-loss transmission of a high current CW beam through a small aperture. The purpose of this test was to determine if an ERL is capable of meeting the stringent requirements imposed by the use of a 1018/cm3 internal gas target proposed for the DarkLight experiment*. Minimal beamline modifications were made to create a machine configuration that is substantially different from those used in routine UV or IR FEL operation. A sustained (8 hour) high power beam run was performed, with clean transmission through a 2 mm transverse aperture of 127 mm length simulating the target configuration. A beam size of 50 um (rms) was measured near the center of the aperture. Experimental data from a week-long test run consistently exhibited beam loss of only a few ppm on the aperture while running 4.5 mA current at 100 MeV -- or nearly 0.5 MW beam power. This surpassed the users? expectation and demonstrated a unique capability of an ERL for this type of experiments. This report presents a summary of the experiment, a brief overview of our activities, and outlines future plans.

  12. Modified composite Fresnel zone plates with high numerical apertures Qing Cao and Jurgen Jahns

    E-Print Network [OSTI]

    Jahns, Jürgen

    Modified composite Fresnel zone plates with high numerical apertures Qing Cao and J¨urgen Jahns Traditional Fresnel zone plates (TFZPs) can be used for the focusing and imaging of soft x-rays and EUV proposed the modified Fresnel zone plates that can produce sharp Gaussian focal spots (we call them

  13. SMALL-APERTURE PHASED ARRAY STUDY OF NOISE FROM COAXIAL JETS

    E-Print Network [OSTI]

    Papamoschou, Dimitri

    SMALL-APERTURE PHASED ARRAY STUDY OF NOISE FROM COAXIAL JETS Dimitri Papamoschou University of California, Irvine, California 92697-3975 The noise source distribution of coaxial jets at variable velocity by fine- scale turbulence (broadside direction). For zero velocity ratio (single-stream jet), the near

  14. A half wave retarder made of bilayer subwavelength metallic apertures

    Office of Scientific and Technical Information (OSTI)

    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 Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnicalInformation4563 LLNL(Technical Report)Asegment, large format(Journal Article) |

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

    E-Print Network [OSTI]

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

    2013-06-25

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

  16. Computational and physical consequences of interaction of closely located simultaneous hydraulic fractures

    E-Print Network [OSTI]

    Rejwer, Ewa

    2015-01-01

    Strong interaction of closely located, nearly parallel hydraulic fractures and its influence on their propagation are studied. Both computational and physical aspects of the problem are considered. It is shown that from the computational point of view, when a distance between cracks is small as compared with their sizes, the system becomes ill-conditioned and numerical results deteriorate. The physical consequence of the interaction consists in decreasing of the crack opening and even greater decrease of conductivity. Then the resistance to fluid flow grows what results in the propagation of only those fractures, the distance between which is large enough. The research aims to suggests a means to overcome the computational difficulty and to improve numerical simulation of hydraulic fractures in shales. Numerical experiments are carried out for a 2D problem by using the complex variable hypersingular boundary element method of higher order accuracy. The condition number of the main matrix of a system, the open...

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

    E-Print Network [OSTI]

    Doe, T.

    2010-01-01

    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

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

    E-Print Network [OSTI]

    Doe, T.

    2010-01-01

    u l y 2 , 1 9 8 1 HYDRAULIC FRACTURING AND OVERCORING STRESSI nun LBL-12478 HYDRAULIC FRACTURING AND OVERCORING STRESSstress. n HYDRAULIC FRACTURING EQUIPMENT AND PROCEDURES The

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

    E-Print Network [OSTI]

    Liu, Weiqun; Li, Yushou; Wang, Bo

    2010-01-01

    Permeability of Fractured Sandstone/Coal Samples Smeulders,8 Gas Permeability of Fractured Sandstone/Coal Samples underthe fractured samples of sandstone and coal and obtain their

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

    SciTech Connect (OSTI)

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

    1996-12-01

    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.

  1. Shale gas and non-aqueous fracturing fluids: Opportunities and challenges for supercritical CO?

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

    Middleton, Richard S.; Carey, James William; Currier, Robert P.; Hyman, Jeffrey De'Haven; Kang, Qinjun; Karra, Satish; Jiménez-Martínez, Joaquín; Porter, Mark L.; Viswanathan, Hari S.

    2015-06-01

    Hydraulic fracturing of shale formations in the United States has led to a domestic energy boom. Currently, water is the only fracturing fluid regularly used in commercial shale oil and gas production. Industry and researchers are interested in non-aqueous working fluids due to their potential to increase production, reduce water requirements, and to minimize environmental impacts. Using a combination of new experimental and modeling data at multiple scales, we analyze the benefits and drawbacks of using CO? as a working fluid for shale gas production. We theorize and outline potential advantages of CO? including enhanced fracturing and fracture propagation, reductionmore »of flow-blocking mechanisms, increased desorption of methane adsorbed in organic-rich parts of the shale, and a reduction or elimination of the deep re-injection of flow-back water that has been linked to induced seismicity and other environmental concerns. We also examine likely disadvantages including costs and safety issues associated with handling large volumes of supercritical CO?. The advantages could have a significant impact over time leading to substantially increased gas production. In addition, if CO? proves to be an effective fracturing fluid, then shale gas formations could become a major utilization option for carbon sequestration.« less

  2. Shale gas and non-aqueous fracturing fluids: Opportunities and challenges for supercritical CO?

    SciTech Connect (OSTI)

    Middleton, Richard S.; Carey, James William; Currier, Robert P.; Hyman, Jeffrey De'Haven; Kang, Qinjun; Karra, Satish; Jiménez-Martínez, Joaquín; Porter, Mark L.; Viswanathan, Hari S.

    2015-06-01

    Hydraulic fracturing of shale formations in the United States has led to a domestic energy boom. Currently, water is the only fracturing fluid regularly used in commercial shale oil and gas production. Industry and researchers are interested in non-aqueous working fluids due to their potential to increase production, reduce water requirements, and to minimize environmental impacts. Using a combination of new experimental and modeling data at multiple scales, we analyze the benefits and drawbacks of using CO? as a working fluid for shale gas production. We theorize and outline potential advantages of CO? including enhanced fracturing and fracture propagation, reduction of flow-blocking mechanisms, increased desorption of methane adsorbed in organic-rich parts of the shale, and a reduction or elimination of the deep re-injection of flow-back water that has been linked to induced seismicity and other environmental concerns. We also examine likely disadvantages including costs and safety issues associated with handling large volumes of supercritical CO?. The advantages could have a significant impact over time leading to substantially increased gas production. In addition, if CO? proves to be an effective fracturing fluid, then shale gas formations could become a major utilization option for carbon sequestration.

  3. Fractures in complex fluids: the case of transient networks

    E-Print Network [OSTI]

    Christian Ligoure; Serge Mora

    2013-01-15

    We present a comprehensive review of the current state of fracture phenomena in transient networks, a wide class of viscoelastic fluids. We will first define what is a fracture in a complex fluid, and recall the main structural and rheological properties of transient networks. Secondly, we review experimental reports on fractures of transient networks in several configurations: shear-induced fractures, fractures in Hele-Shaw cells and fracture in extensional geometries (filament stretching rheometry and pendant drop experiments), including fracture propagation. The tentative extension of the concepts of brittleness and ductility to the fracture mechanisms in transient networks is also discussed. Finally, the different and apparently contradictory theoretical approaches developed to interpret fracture nucleation will be addressed and confronted to experimental results. Rationalized criteria to discriminate the relevance of these different models will be proposed.

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

    SciTech Connect (OSTI)

    Hai Huang; Ben Spencer; Jason Hales

    2014-10-01

    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.

  5. Three-dimensional Modeling of Acid Transport and Etching in a Fracture 

    E-Print Network [OSTI]

    Oeth, Cassandra V

    2013-11-25

    Acid fracture stimulation generates higher well production but requires engineering design for treatment optimization. To quantify the cost and benefit of a particular acid fracture treatment an engineer must predict the resulting fracture’s...

  6. Mechanical Behavior of Small-Scale Channels in Acid-etched Fractures 

    E-Print Network [OSTI]

    Deng, Jiayao

    2011-02-22

    The conductivity of acid-etched fractures highly depends on spaces along the fracture created by uneven etching of the fracture walls remaining open after fracture closure. Formation heterogeneities such as variations of mineralogy and permeability...

  7. Austin chalk fracture mapping using frequency data derived from seismic data 

    E-Print Network [OSTI]

    Najmuddin, Ilyas Juzer

    2004-09-30

    , is difficult on seismic sections. Fracturing changes the rock properties and therefore the attributes of the seismic data reflecting off the fractured interface, and data passing through the fractured layers. Fractures have a scattering effect on seismic energy...

  8. A microstructural study of the extension-to-shear fracture transition in Carrara Marble 

    E-Print Network [OSTI]

    Rodriguez, Erika

    2005-11-01

    Triaxial extension experiments on Carrara Marble demonstrate that there is a continuous transition from extension to shear fracture on the basis of mechanical behavior, macroscopic fracture orientation and fracture morphology where hybrid fractures...

  9. Investigation of the influence of stress shadows on horizontal hydraulic fractures from adjacent lateral wells

    E-Print Network [OSTI]

    Investigation of the influence of stress shadows on horizontal hydraulic fractures from adjacent: Unconventional hydraulic fracturing Stress shadow Adjacent lateral wells Simulfrac and zipperfrac Numerical the simultaneous or near simultaneous hydraulic fracturing of adjacent lateral wells to maximize the fracture

  10. A robust method for fracture orientation and density detection from seismic scattered energy

    E-Print Network [OSTI]

    Fang, Xinding

    2011-01-01

    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 ...

  11. A cubic matrix-fracture geometry model for radial tracer flow in naturally fractured reservoirs

    SciTech Connect (OSTI)

    Jetzabeth Ramirez-Sabag; Fernando Samaniego V.

    1992-01-01

    This study presents a general solution for the radial flow of tracers in naturally fractured reservoirs, with cubic blocks matrix-fracture geometry. Continuous and finite step injection of chemical and radioactive tracers are considered. The reservoir is treated as being composed of two regions: a mobile where dispersion and convection take place and a stagnant where only diffusion and adsorption are allowed. Radioactive decay is considered in both regions. The model of this study is thoroughly compared under proper simplified conditions to those previously presented in the literature. The coupled matrix to fracture solution in the Laplace space is numerically inverted by means of the Crump algorithm. A detailed validation of the model with respect to solutions previously presented and/or simplified physical conditions solutions (i.e., homogeneous case) or limit solutions (i.e., naturally fractured nearly homogeneous) was carried out. The influence of the three of the main dimensionless parameters that enter into the solution was carefully investigated. A comparison of results for three different naturally fractured systems, vertical fractures (linear flow), horizontal fractures (radial flow) and the cubic geometry model of this study, is presented.

  12. Simulation on Discrete Fracture Network Using Flexible Voronoi Gridding 

    E-Print Network [OSTI]

    Syihab, Zuher

    2011-02-22

    Fractured reservoirs are generally simulated using Warren and Root26 dual-porosity (DP) approach. The main assumption of this approach is that the geometry of fractures are uniformly distributed and interconnected in ...

  13. 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.

  14. Effectiveness of microseismic monitoring for optimizing hydraulic fracturing in California

    E-Print Network [OSTI]

    Alampi, Ann M

    2014-01-01

    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 ...

  15. Numerical Modeling of Hydraulic Fracturing in Oil Sands

    E-Print Network [OSTI]

    2008-11-16

    Hydraulic fracturing is a widely used and e cient technique for enhancing oil extraction from heavy oil sands ..... phenomenon are the main issues involved in hydraulic fracturing. ..... energy ux due to conduction and convection: Lei = @T. @xi.

  16. The Role of Acidizing in Proppant Fracturing in Carbonate Reservoirs 

    E-Print Network [OSTI]

    Densirimongkol, Jurairat

    2010-10-12

    Today, optimizing well stimulation techniques to obtain maximum return of investment is still a challenge. Hydraulic fracturing is a typical application to improve ultimate recovery from oil and gas reservoirs. Proppant fracturing has become one...

  17. Acid Fracturing Feasibility Study for Heterogeneous Carbonate Formation 

    E-Print Network [OSTI]

    Suleimenova, Assiya

    2015-03-03

    Acid fracturing is a stimulation technique that is commonly used by the industry to increase productivity or injectivity of wells in carbonate reservoirs. To determine a feasibility of acid fracturing treatment for a heterogeneous formation...

  18. Experimental Study of Acid Fracture Conductivity of Austin Chalk Formation 

    E-Print Network [OSTI]

    Nino Penaloza, Andrea

    2013-05-01

    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...

  19. Fracture characterization from seismic measurements in a borehole

    E-Print Network [OSTI]

    Bakku, Sudhish Kumar

    2015-01-01

    Fracture characterization is important for optimal recovery of hydrocarbons. In this thesis, we develop techniques to characterize natural and hydraulic fractures using seismic measurements in a borehole. We first develop ...

  20. How can we use one fracture to locate another?

    E-Print Network [OSTI]

    Poliannikov, Oleg V.

    2011-01-01

    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 ...

  1. Numerical modeling of hydraulic fracture initiation and development

    E-Print Network [OSTI]

    2007-05-25

    Calculation scheme for modeling a hydraulic fracturing process: horizontal section of a ...... Jr., “Overview of current hydraulic fracturing design and treatment technology. .... A. A. Dobroskok, A. Ghassemi, and A. M. Linkov, “Extended structural ...

  2. On equivalence of thinning fluids used for hydraulic fracturing

    E-Print Network [OSTI]

    Linkov, Alexander

    2012-01-01

    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...

  3. Hydraulic Fracture Monitoring: A Jonah Field Case Study

    E-Print Network [OSTI]

    Seher, T.

    2011-01-01

    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 ...

  4. Fracture Characterization from Scattered Energy: A Case Study

    E-Print Network [OSTI]

    Grandi, Samantha K.

    2006-01-01

    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. ...

  5. Streamline-based production data integration in naturally fractured reservoirs 

    E-Print Network [OSTI]

    Al Harbi, Mishal H.

    2005-08-29

    dualporosity streamline model for fracture flow simulation by treating the fracture and matrix as separate continua that are connected through a transfer function. Next, we analytically compute the sensitivities that define the relationship between...

  6. Geomechanical Development of Fractured Reservoirs During Gas Production 

    E-Print Network [OSTI]

    Huang, Jian

    2013-04-05

    Within fractured reservoirs, such as tight gas reservoir, coupled processes between matrix deformation and fluid flow are very important for predicting reservoir behavior, pore pressure evolution and fracture closure. To study the coupling between...

  7. Analysis of Scattered Signal to Estimate Reservoir Fracture Parameters

    E-Print Network [OSTI]

    Grandi, Samantha K.

    We detect fracture corridors and determine their orientation and average spacing based on an analysis of seismic coda in the frequency-wave number (f-k ) domain. Fracture corridors have dimensions similar to seismic ...

  8. A Bayesian framework for fracture characterization from surface seismic data

    E-Print Network [OSTI]

    Zamanian, S. Ahmad

    2012-01-01

    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 ...

  9. Seismic characterization of fractured reservoirs by focusing Gaussian beams

    E-Print Network [OSTI]

    Zheng, Yingcai

    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 ...

  10. Finite Difference Modeling of Seismic Responses to Intersecting Fracture Sets

    E-Print Network [OSTI]

    Chi, Shihong

    2006-01-01

    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 ...

  11. Effects of subsurface fracture interactions on surface deformation

    E-Print Network [OSTI]

    Jerry, Ruel (Ruel Valentine)

    2013-01-01

    Although the surface deformation resulting from the opening of a single fracture in a layered elastic half-space resembles the observed deformation at the InSalah site, it seems unlikely that only a single fracture is ...

  12. Compartmentalization analysis using discrete fracture network models

    SciTech Connect (OSTI)

    La Pointe, P.R.; Eiben, T.; Dershowitz, W.; Wadleigh, E.

    1997-08-01

    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.

  13. Fracture Toughness Prediction for MWCNT Reinforced Ceramics

    SciTech Connect (OSTI)

    Henager, Charles H.; Nguyen, Ba Nghiep

    2013-09-01

    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.

  14. Optimized focal and pupil plane masks for vortex coronagraphs on telescopes with obstructed apertures

    E-Print Network [OSTI]

    Ruane, Garreth J; Huby, Elsa; Mawet, Dimitri; Delacroix, Christian; Carlomagno, Brunella; Piron, Pierre; Swartzlander, Grover A

    2015-01-01

    We present methods for optimizing pupil and focal plane optical elements that improve the performance of vortex coronagraphs on telescopes with obstructed or segmented apertures. Phase-only and complex masks are designed for the entrance pupil, focal plane, and the plane of the Lyot stop. Optimal masks are obtained using both analytical and numerical methods. The latter makes use of an iterative error reduction algorithm to calculate "correcting" optics that mitigate unwanted diffraction from aperture obstructions. We analyze the achieved performance in terms of starlight suppression, contrast, off-axis image quality, and chromatic dependence. Manufacturing considerations and sensitivity to aberrations are also discussed. This work provides a path to joint optimization of multiple coronagraph planes to maximize sensitivity to exoplanets and other faint companions.

  15. Measured Aperture-Array Noise Temperature of the Mark II Phased Array Feed for ASKAP

    E-Print Network [OSTI]

    Chippendale, A P; Beresford, R J; Hampson, G A; Shaw, R D; Hayman, D B; Macleod, A; Forsyth, A R; Hay, S G; Leach, M; Cantrall, C; Brothers, M L; Hotan, A W

    2015-01-01

    We have measured the aperture-array noise temperature of the first Mk. II phased array feed that CSIRO has built for the Australian Square Kilometre Array Pathfinder telescope. As an aperture array, the Mk. II phased array feed achieves a beam equivalent noise temperature less than 40 K from 0.78 GHz to 1.7 GHz and less than 50 K from 0.7 GHz to 1.8 GHz for a boresight beam directed at the zenith. We believe these are the lowest reported noise temperatures over these frequency ranges for ambient-temperature phased arrays. The measured noise temperature includes receiver electronics noise, ohmic losses in the array, and stray radiation from sidelobes illuminating the sky and ground away from the desired field of view. This phased array feed was designed for the Australian Square Kilometre Array Pathfinder to demonstrate fast astronomical surveys with a wide field of view for the Square Kilometre Array.

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

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

    fabricate and test a downhole instrument for measuring fracture flow following a hydraulic stimulation experiment. reservoirrosetracerscharacterizefractures.pdf More...

  17. Estimation of fracture parameters from reflection seismic data - Part I ...

    E-Print Network [OSTI]

    A. Bakulin, V. Grechka, I. Tsvankin

    2000-11-02

    rocks requires accounting for the hydraulic interaction between cracks and pores. INTRODUCTION. Seismic detection of subsurface fractures has important ap-.

  18. Experimental and Analytical Research on Fracture Processes in ROck

    SciTech Connect (OSTI)

    Herbert H.. Einstein; Jay Miller; Bruno Silva

    2009-02-27

    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.

  19. Dynamic fracturing: eld and experimental observations Amir Sagy*, Ze'ev Reches, Itzhak Roman

    E-Print Network [OSTI]

    Ze'ev, Reches

    Dynamic fracturing: ®eld and experimental observations Amir Sagy*, Ze'ev Reches, Itzhak Roman three styles of fracturing: planar fractures, known from previous tests; branching fractures and clustering fractures, observed here for the ®rst time in layered composites. Based on fracture morphology, we

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

    DOE Patents [OSTI]

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

    2014-04-29

    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.

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

    DOE Patents [OSTI]

    Khounsary, Ali M. (Hinsdale, IL)

    2012-05-22

    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.

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

    DOE Patents [OSTI]

    Fenimore, E.E.

    1980-09-26

    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.

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

    E-Print Network [OSTI]

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

    2015-01-01

    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...

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

    E-Print Network [OSTI]

    Wang, Wenxin

    2006-04-12

    This thesis presents and develops efficient and effective methodologies for optimal hydraulic fracture design and fracture performance evaluation. These methods incorporate algorithms that simultaneously optimize all of the treatment parameters...

  5. 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

  6. The Transport of Nuclear Contamination in Fractured Porous Media

    E-Print Network [OSTI]

    Douglas Jr., Jim

    The Transport of Nuclear Contamination in Fractured Porous Media Jim Douglas, Jr. #3; Anna M and dispersion of nuclear contamination through a granitic medium having densely spaced fractures, Rochester, MI 48309-4485 1 #12; Nuclear Contamination in Fractured Porous Media 2 2 The Single Porosity

  7. Estimating Major and Minor Natural Fracture Patterns in Gas

    E-Print Network [OSTI]

    Mohaghegh, Shahab

    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

  8. Creation and Impairment of Hydraulic Fracture Conductivity in Shale Formations 

    E-Print Network [OSTI]

    Zhang, Junjing

    2014-07-10

    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...

  9. 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

  10. 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

  11. Hydraulic Fractures: multiscale phenomena, asymptotic and numerical solutions

    E-Print Network [OSTI]

    Peirce, Anthony

    Hydraulic Fractures: multiscale phenomena, asymptotic and numerical solutions SANUM Conference (UMN) Eduard Siebrits (SLB) #12;2 Outline · Examples of hydraulic fractures · Governing equations well stimulation Fracturing Fluid Proppant #12;5 Quarries #12;6 Magma flow Tarkastad #12;7 Model EQ 1

  12. Hydraulic Fractures: multiscale phenomena, asymptotic and numerical solutions

    E-Print Network [OSTI]

    Peirce, Anthony

    Hydraulic Fractures: multiscale phenomena, asymptotic and numerical solutions CSIRO CSS TCP Detournay (UMN) Eduard Siebrits (SLB) #12;2 Outline · Examples of hydraulic fractures · Governing equations well stimulation Fracturing Fluid Proppant #12;5 Quarries #12;6 Magma flow Tarkastad #12;7 Model EQ 1

  13. Poroelastic modeling of seismic boundary conditions across a fracture

    E-Print Network [OSTI]

    2007-07-20

    Permeability of a fracture can affect how the fracture interacts with seismic waves. To examine this effect ... seismic wave scattering off nonplanar e.g., curved and intersecting fractures. ..... values, this can result in a significant error in evaluating the average fluid pressure .... As seen from the plot, the transition be- tween the ...

  14. Automatic Fracture Reduction Thomas Albrecht and Thomas Vetter

    E-Print Network [OSTI]

    Vetter, Thomas

    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

  15. 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

  16. 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

  17. Fibre Based Modeling of Wood Dynamics and Fracture

    E-Print Network [OSTI]

    Bridson, Robert

    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

  18. In vitro fracture toughness of human dentin V. Imbeni,1

    E-Print Network [OSTI]

    Ritchie, Robert

    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

  19. Fracture Toughness of MDF and other Materials with Fiber Bridging

    E-Print Network [OSTI]

    Nairn, John A.

    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

  20. Introduction Fracture at small length scales is a concern

    E-Print Network [OSTI]

    Suo, Zhigang

    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

  1. Fracture surface energy of the Punchbowl fault, San Andreas system

    E-Print Network [OSTI]

    Chester, Frederick M.

    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

  2. Fracture patterns in thin films and multilayers Alex A. Volinsky

    E-Print Network [OSTI]

    Volinsky, Alex A.

    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

  3. Meshfree Simulations of Spall Fracture By Bo Ren ,

    E-Print Network [OSTI]

    Li, Shaofan

    Meshfree Simulations of Spall Fracture By Bo Ren , , Shaofan Li, , Jing Qian , Xiaowei Zeng Shock wave induced spall fracture is a complex multiscale phenomenon, and it is a challenge to build a constitutive and computational model that can capture the essential features of the spall fracture

  4. Molecular dynamics study of fracture accompanied by chemical reaction

    E-Print Network [OSTI]

    Krivtsov, Anton M.

    Molecular dynamics study of fracture accompanied by chemical reaction Anton M. Krivtsov akrivtsov@bk.ru Abstract A molecular dynamics model for fracture accompanied by chemical reac- tion is suggested. Crack of the initial and new specimen surfaces during the fracture process is taken into account. It is pos- tulated

  5. Influence of defects distribution and specimen size on fracture initiation

    E-Print Network [OSTI]

    Krivtsov, Anton M.

    Influence of defects distribution and specimen size on fracture initiation Anton M. Krivtsov akrivtsov@bk.ru Abstract An analytical model for the scale dependence of the fracture initiation is suggested. The model is based on the idea that fracture is a stochastic process, for the bigger specimens

  6. Short communication Fractal in fracture of bulk metallic glass

    E-Print Network [OSTI]

    Gao, Jianbo

    Short communication Fractal in fracture of bulk metallic glass M.Q. Jiang a,b , J.X. Meng a , J. Bulk metallic glass B. Dynamic fracture C. Nanoscale periodic corrugation C. Fractal a b s t r a c t We investigate the nanoscale periodic corrugation (NPC) structures on the dynamic fracture surface of a typical

  7. A dimensional decomposition method for stochastic fracture mechanics

    E-Print Network [OSTI]

    Rahman, Sharif

    A dimensional decomposition method for stochastic fracture mechanics Sharif Rahman * Department required by the proposed method can be viewed as performing deterministic fracture analyses at selected, no derivatives of fracture response are required by the new method developed. Results of three numerical exam

  8. A Cohesive Approach to Thin-Shell Fracture and Fragmentation

    E-Print Network [OSTI]

    Cirak, Fehmi

    A Cohesive Approach to Thin-Shell Fracture and Fragmentation Fehmi Cirak1 , Michael Ortiz2 and Anna 20133 Milano, Italy Abstract We develop a finite-element method for the simulation of dynamic fracture and the fracture along the element edges is modeled with a cohesive law. In order to follow the prop- agation

  9. RESIDUAL STRESS EFFECTS IN FRACTURE OF COMPOSITES AND ADHESIVES

    E-Print Network [OSTI]

    Nairn, John A.

    RESIDUAL STRESS EFFECTS IN FRACTURE OF COMPOSITES AND ADHESIVES JOHN A. NAIRN ABSTRACT Because by including residual stresses in fracture mechanics models of failure. This chapter gives general results examples of including residual stresses in fracture mechanics interpretation of experimental results

  10. A unified enrichment scheme for fracture Safdar Abbas

    E-Print Network [OSTI]

    A unified enrichment scheme for fracture problems Safdar Abbas Thomas-Peter Fries AICES, RWTH XFEM in fracture mechanics Numerical examples (cohesionless cracks) Numerical examples (cohesive cracks) Conclusions Future outlook 2 #12;Motivation Outline Motivation XFEM in fracture mechanics Numerical examples

  11. Finite Element Model of Fracture Formation on Growing Surfaces

    E-Print Network [OSTI]

    Prusinkiewicz, Przemyslaw

    Finite Element Model of Fracture Formation on Growing Surfaces Pavol Federl and Przemyslaw-mail: federl|pwp@cpsc.ucalgary.ca Abstract We present a model of fracture formation on surfaces of bilayered materials. The model makes it possible to synthesize patterns of fractures induced by growth or shrinkage

  12. Analyzing and Simulating Fracture Patterns of Theran Wall Paintings

    E-Print Network [OSTI]

    Singh, Jaswinder Pal

    10 Analyzing and Simulating Fracture Patterns of Theran Wall Paintings HIJUNG SHIN, Princeton and Akrotiri Excavation TIM WEYRICH, University College London In this article, we analyze the fracture that suggests a hierarchical fracture pattern where fragments break into two pieces recursively along cracks

  13. Gaseous Detonation-Driven Fracture of Tubes Tong Wa Chao

    E-Print Network [OSTI]

    Barr, Al

    Gaseous Detonation-Driven Fracture of Tubes Thesis by Tong Wa Chao In Partial Fulfillment An experimental investigation of fracture response of aluminum 6061-T6 tubes under internal gaseous detonation of this particular traveling load and tube geometry produced fracture data not available before in the open

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

    SciTech Connect (OSTI)

    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)

    2013-11-01

    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.

  15. Performances of High Numerical Aperture Water and Oil Immersion Objective in Deep-Tissue, Multi-Photon

    E-Print Network [OSTI]

    So, Peter

    Performances of High Numerical Aperture Water and Oil Immersion Objective in Deep-Tissue, Multi Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 3 Univerlever Edgewater Laboratory, Edgewater, New Jersey 07020 4 Department of Mechanical Engineering, Massachusetts Institute

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

    E-Print Network [OSTI]

    Accorsi, Roberto, 1971-

    2001-01-01

    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 ...

  17. 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)

    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)

    2014-03-10

    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.

  18. A Global Model for Fracture Falloff Analysis 

    E-Print Network [OSTI]

    Marongiu-Porcu, Matteo

    2014-10-29

    and estimate of the induced fracture geometry) as well as reservoir permeability and formation pressure, provided that enough time is allowed for the falloff to reach pseudo-radial flow regime. Both oil and gas reservoirs can be effectively studied. Another...

  19. Gas condensate damage in hydraulically fractured wells 

    E-Print Network [OSTI]

    Adeyeye, Adedeji Ayoola

    2004-09-30

    This project is a research into the effect of gas condensate damage in hydraulically fractured wells. It is the result of a problem encountered in producing a low permeability formation from a well in South Texas owned by the El Paso Production...

  20. Interference Fracturing: Non-Uniform Distributions of Perforation Clusters that Promote Simultaneous Growth of Multiple Hydraulic Fractures

    E-Print Network [OSTI]

    Peirce, Anthony

    of Bunger et al. (In Press) is consistent with past observations of multiple hydraulic fracture growth from 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

  1. Interference Fracturing: Non-Uniform Distributions of Perforation Clusters that Promote Simultaneous Growth of Multiple Hydraulic Fractures

    E-Print Network [OSTI]

    Peirce, Anthony

    Simultaneous Growth of Multiple Hydraulic Fractures A.P. Peirce, University of British Columbia and A.P. Bunger hurdles in horizontal well stimulation is the generation of hydraulic fractures (HFs) from all perforation shadowing" that refers to suppression of some hydraulic fractures by the compressive stresses exerted

  2. Investigation of the influence of natural fractures and in situ stress on hydraulic fracture propagation using a

    E-Print Network [OSTI]

    ARTICLE Investigation of the influence of natural fractures and in situ stress on hydraulic: Hydraulic fracturing is the primary means for enhancing rock mass permeability and improving well productiv- ity in tight reservoir rocks. Significant advances have been made in hydraulic fracturing theory

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

    SciTech Connect (OSTI)

    Wood, James R.; Harrison, William B.

    2002-12-02

    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.

  4. Risk assessment for osteoporotic fractures among men and women from a prospective population study: the EPIC-Norfolk study

    E-Print Network [OSTI]

    Moayyeri, Alireza

    2012-03-06

    . In this thesis, I aimed to evaluate novel risk factors for osteoporosis and develop a fracture risk assessment model among the middle-aged and older people. I used data from the European Prospective Investigation into Cancer (EPIC)-Norfolk study, which is a large...

  5. Aperture lamp

    DOE Patents [OSTI]

    MacLennan, Donald A. (Gaithersburg, MD); Turner, Brian P. (Damascus, MD)

    2003-01-01

    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.

  6. Natural Fracture Characterization by Source Mechanism Estimation and Semi-Stochastic Generation of Discrete Fracture Networks Using Microseismic and Core Data 

    E-Print Network [OSTI]

    Sotelo Gamboa, Edith

    2014-11-12

    The overall goal of this study is to generate discrete fracture networks using microseismic and core data from a natural fractured reservoir that has been hydraulically stimulated. To improve fracture characterization, a ...

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

    E-Print Network [OSTI]

    Cappa, F.

    2009-01-01

    of each hydraulic parameter, as well as the importance ofmagnitude was well captured with a hydraulic aperture of 5 ×time-lag was well matched with a smaller hydraulic aperture

  8. Molecular basis of fracture in polystyrene films

    SciTech Connect (OSTI)

    Sambasivam, M.; Klein, A.; Thomas, T.N.; Mohammadi, N.; Sperling, L.H. [Lehigh Univ., Bethlehem, PA (United States)

    1993-12-31

    To understand the molecular mechanisms involved in the fracture of polystyrene films, a custom built dental burr grinding instrument was used. Films were made from latexes, compression molded polystyrene, and by photopolymerization. Latexes were prepared by direct miniemulsification of polystyrene using sodium lauryl sulfate as surfactant and cetyl and stearyl alcohols as co-surfactants. Grinding of various films was carried out at room temperature. GPC was used to determine the molecular weight before and after grinding. From the molecular weight reduction, the number of chain scissions per unit volume was determined. The energy required for the grinding process was also measured. The results are consistent with a model of exciting 300{+-}150 bonds (per chain fracture) to the breaking point. The most probable deformation mode, consuming maximum energy is envisaged as the scissor-like opening of the 109{degrees} -C-C-C bond angle.

  9. Fracture simulation for zirconia toughened alumina microstructure

    E-Print Network [OSTI]

    Kim, Kyungmok; Forest, Bernard

    2013-01-01

    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...

  10. Broadband enhanced transmission through the stacked metallic multi-layers perforated with coaxial annular apertures

    E-Print Network [OSTI]

    Wei, Zeyong; Fan, Yuancheng; Yu, Xing; Li, Hongqiang

    2011-01-01

    This paper theoretically and experimentally presents a first report on broadband enhanced transmission through stacked metallic multi-layers perforated with coaxial annular apertures (CAAs). Different from previous studies on extraordinary transmission that occurs at a single frequency, the enhanced transmission of our system with two or three metallic layers can span a wide frequency range with a bandwidth about 60% of the central frequency. The phenomena arise from the excitation and hybridization of guided resonance modes in CAAs among different layers. Measured transmission spectra are in good agreement with calculations semi-analytically resolved by modal expansion method.

  11. Fracture of Thermosetting Polymers: Experiments and Modeling 

    E-Print Network [OSTI]

    Benzerga, Amine; Burgess, Brad

    2011-08-04

    of a resin known as epoxy E862, which is a polymer resin currently explored by NASA researchers, and then model this behavior using FEM. In the early 1990's, successful computational methodologies for modeling fracture of metal-matrix composites... of Aerospace Engineering Aircraft are becoming extremely complex in the modern age. Fueled by the advent of new technology, a modern plane?s makeup and structure are changing considerably. Recently the idea to utilize a greater amount of composite...

  12. FRACTURE FAILURE CRITERIA OF SOFC PEN STRUCTURE

    SciTech Connect (OSTI)

    Liu, Wenning N.; Sun, Xin; Khaleel, Mohammad A.; Qu, Jianmin

    2007-04-30

    Thermal stresses and warpage of the PEN are unavoidable due to the temperature changes from the stress-free sintering temperature to room temperature and mismatch of the coefficients of thermal expansion (CTE) of various layers in the PEN structures of solid oxide fuel cells (SOFC) during the PEN manufacturing process. In the meantime, additional mechanical stresses will also be created by mechanical flattening during the stack assembly process. The porous nature of anode and cathode in the PEN structures determines presence of the initial flaws and crack on the interfaces of anode/electrolyte/cathode and in the interior of the materials. The sintering/assembling induced stresses may cause the fracture failure of PEN structure. Therefore, fracture failure criteria for SOFC PEN structures is developed in order to ensure the structural integrity of the cell and stack of SOFC. In this paper, the fracture criteria based on the relationship between the critical energy release rate and critical curvature and maximum displacement of the warped cells caused by the temperature changes as well as mechanical flattening process is established so that possible failure of SOFC PEN structures may be predicted deterministically by the measurement of the curvature and displacement of the warped cells.

  13. Field-Scale Effective Matrix Diffusion Coefficient for FracturedRock: Results From Literature Survey

    SciTech Connect (OSTI)

    Zhou, Quanlin; Liu, Hui Hai; Molz, Fred J.; Zhang, Yingqi; Bodvarsson, Gudmundur S.

    2005-03-28

    Matrix diffusion is an important mechanism for solutetransport in fractured rock. We recently conducted a literature survey onthe effective matrix diffusion coefficient, Dem, a key parameter fordescribing matrix diffusion processes at the field scale. Forty fieldtracer tests at 15 fractured geologic sites were surveyed and selectedfor study, based on data availability and quality. Field-scale Dem valueswere calculated, either directly using data reported in the literature orby reanalyzing the corresponding field tracer tests. Surveyed dataindicate that the effective-matrix-diffusion-coefficient factor FD(defined as the ratio of Dem to the lab-scale matrix diffusioncoefficient [Dem]of the same tracer) is generally larger than one,indicating that the effective matrix diffusion coefficient in the fieldis comparatively larger than the matrix diffusion coefficient at therock-core scale. This larger value could be attributed to the manymass-transfer processes at different scales in naturally heterogeneous,fractured rock systems. Furthermore, we observed a moderate trend towardsystematic increase in the emDFmDDF value with observation scale,indicating that the effective matrix diffusion coefficient is likely tobe statistically scale dependent. The FD value ranges from 1 to 10,000for observation scales from 5 to 2,000 m. At a given scale, the FD valuevaries by two orders of magnitude, reflecting the influence of differingdegrees of fractured rock heterogeneity at different sites. In addition,the surveyed data indicate that field-scale longitudinal dispersivitygenerally increases with observation scale, which is consistent withprevious studies. The scale-dependent field-scale matrix diffusioncoefficient (and dispersivity) may have significant implications forassessing long-term, large-scale radionuclide and contaminant transportevents in fractured rock, both for nuclear waste disposal and contaminantremediation.

  14. A novel pillar indentation splitting test for measuring fracture toughness of thin ceramic coatings

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

    Sebastiani, Marco; Johanns, K.; Herbert, Erik G.; Bemporad, Edoardo; Carassiti, Fabio; Pharr, George Mathews

    2015-01-01

    The fracture toughness of thin ceramic films is an important material property that plays a role in determining the in-service mechanical performance and adhesion of this important class of engineering materials. Unfortunately, measurement of thin film fracture toughness is affected by influences from the substrate and the large residual stresses that can exist in the films. In this paper, we explore a promising new technique that potentially overcomes these issues based on nanoindentation testing of micro-pillars produced by focused ion beam milling of the films. By making the pillar diameter approximately equal to its length, the residual stress in themore »upper portion of the pillar is almost fully relaxed, and when indented with a sharp Berkovich indenter, the pillars fracture by splitting at reproducible loads that are readily quantified by a sudden displacement excursion in the load displacement behavior. Cohesive finite element simulations are used for analysis and development of a simple relationship between the critical load at failure, pillar radius, and fracture toughness for a given material. The main novel aspect of this work is that neither crack geometries nor crack sizes need to be measured post test. In addition, the residual stress can be measured at the same time with toughness, by comparison of the indentation results obtained on the stress-free pillars and the as-deposited film. The method is tested on three different hard coatings created by physical vapor deposition, namely titanium nitride (TiN), chromium nitride (CrN) and a CrAlN-Si?N? nanocomposite. Results compare well to independently measured values of fracture toughness for the three brittle films. The technique offers several benefits over existing methods.« less

  15. A novel pillar indentation splitting test for measuring fracture toughness of thin ceramic coatings

    SciTech Connect (OSTI)

    Sebastiani, Marco; Johanns, K.; Herbert, Erik G.; Bemporad, Edoardo; Carassiti, Fabio; Pharr, George Mathews

    2015-01-01

    The fracture toughness of thin ceramic films is an important material property that plays a role in determining the in-service mechanical performance and adhesion of this important class of engineering materials. Unfortunately, measurement of thin film fracture toughness is affected by influences from the substrate and the large residual stresses that can exist in the films. In this paper, we explore a promising new technique that potentially overcomes these issues based on nanoindentation testing of micro-pillars produced by focused ion beam milling of the films. By making the pillar diameter approximately equal to its length, the residual stress in the upper portion of the pillar is almost fully relaxed, and when indented with a sharp Berkovich indenter, the pillars fracture by splitting at reproducible loads that are readily quantified by a sudden displacement excursion in the load displacement behavior. Cohesive finite element simulations are used for analysis and development of a simple relationship between the critical load at failure, pillar radius, and fracture toughness for a given material. The main novel aspect of this work is that neither crack geometries nor crack sizes need to be measured post test. In addition, the residual stress can be measured at the same time with toughness, by comparison of the indentation results obtained on the stress-free pillars and the as-deposited film. The method is tested on three different hard coatings created by physical vapor deposition, namely titanium nitride (TiN), chromium nitride (CrN) and a CrAlN-Si?N? nanocomposite. Results compare well to independently measured values of fracture toughness for the three brittle films. The technique offers several benefits over existing methods.

  16. Curvilinear gullies, lobate deposits and fractures, and their implications for the geologic evolution and hydration of Vesta

    E-Print Network [OSTI]

    Scully, Jennifer Eva

    2015-01-01

    and impact- induced fracturing, it has remained largelyof impact-induced fracturing in the northern hemisphere andand impact-induced fracturing throughout its history.

  17. Micromechanisms of ductile fracturing of DH-36 steel plates under impulsive loads and influence of polyurea reinforcing

    E-Print Network [OSTI]

    Amini, M. R.; Nemat-Nasser, S.

    2010-01-01

    Micromechanisms of ductile fracturing of DH-36 steel platesMicromechanisms of ductile fracturing of DH-36 steel platesundergoes controllable fracturing, generally initiated near

  18. FRACTURE MECHANISM OF A BAINITE STEEL IN PRECRACKED AND NOTCHED SPECIMENS

    E-Print Network [OSTI]

    Qin, Qinghua

    . KEYWORDS Fracture toughness, cleavage fracture, crack depth, ductile crack growth, bainite steel, fracture specimens fractured at lower-shelf region without any ductile crack growth. The critical crack tip opening there was an apparent improvement in fracture toughness (KIC) measured using precracked specimens but a decrease

  19. Mixed-mode fracture of human cortical bone Elizabeth A. Zimmermann a,b

    E-Print Network [OSTI]

    Ritchie, Robert

    Mixed-mode fracture of human cortical bone Elizabeth A. Zimmermann a,b , Maximilien E. Launey Available online 1 July 2009 Keywords: Human cortical bone Mixed-mode fracture Fracture toughness Fracture mechanisms a b s t r a c t Although the mode I (tensile opening) fracture toughness has been the focus

  20. Author's personal copy Calibration procedures for a computational model of ductile fracture

    E-Print Network [OSTI]

    Hutchinson, John W.

    Author's personal copy Calibration procedures for a computational model of ductile fracture Z. Xue fracture Computational fracture Shear fracture Damage parameters a b s t r a c t A recent extension of the cup-cone fracture mode in the neck of a round tensile bar. Ductility of a notched round bar provides

  1. Material Point Method Simulations of Transverse Fracture in Wood with Realistic Morphologies

    E-Print Network [OSTI]

    Nairn, John A.

    Material Point Method Simulations of Transverse Fracture in Wood with Realistic Morphologies By J Material point method Numerical modeling RT fracture TR fracture; Transverse fracture Summary A new used to simulate transverse fracture in solid wood. The simulations were run on the scale of growth

  2. Integrated seismic study of naturally fractured tight gas reservoirs. Technical progress report, April 1, 1993--June 31, 1993

    SciTech Connect (OSTI)

    Mavko, G.; Nur, A.

    1993-07-26

    This was the seventh quarter of the contract. During this quarter we (1) continued the large task of processing the seismic data, (2) collected additional geological information to aid in the interpretation, (3) tied the well log data to the seismic via generation of synthetic seismograms, (4) began integrating regional structural information and fracture trends with our observations of structure in the study area, (5) began constructing a velocity model for time-to-depth conversion and subsequent AVO and raytrace modeling experiments, and (6) completed formulation of some theoretical tools for relating fracture density to observed elastic anisotropy. The study area is located at the southern end of the Powder River Basin in Converse County in east-central Wyoming. It is a low permeability fractured site, with both gas and oil present. Reservoirs are highly compartmentalized due to the low permeabilities, and fractures provide the only practical drainage paths for production. The two formations of interest are: The Niobrara: a fractured shale and limey shale to chalk, which is a reservoir rock, but also its own source rock. The Frontier: a tight sandstone lying directly below the Niobrara, brought into contact with it by an unconformity. A basemap is presented with the seismic lines being analyzed for this project plus locations of 13 wells that we are using to supplement the analysis. The arrows point to two wells for which we have constructed synthetic seismograms.

  3. Characterization and significance of a stylolitic fracture system determined from horizontal core and borehole imaging data, Hanifa Reservoir, Abqaiq Field (SA)

    SciTech Connect (OSTI)

    Luthy, S.T.; Grover, G. [Saudi Aramco, Dhahran (Saudi Arabia); Wiltse, E. [Schlumberger, Al-Khobar (Saudi Arabia)

    1995-08-01

    The Hanifa reservoir at Abqaiq Field, eastern Saudi Arabia, consists of microporous (up to 30% porosity) lime mudstones with low matrix permeability (< 10 md). SEM imagery reveals a crystal framework texture of micro-rhombic calcite crystals with 2-5 {mu}m-sized intercrystalline pore spaces. Fluid transmissibility was preliminarily identified as via fractures as indicated by no stratigraphic predictability to fluid flow, high flow over thin stratigraphic intervals, little relationship between high flow and high porosity intervals, large disparity between core Kh and well-test Kh, and observation offractures in cores and borehole imaging logs front horizontal Hanifa wells. Integration of descriptions from over 4000 fractures observed in borehole images together with descriptions of over 500 fractures identified from vertica1 and horizontal cores has resulted in further characterization of the fracture system. The fractures are open to partially-open, with an east-to northeast orientation, and they cluster in low porosity zones which are characterized by intense stylolitization. These sub-parallel, nearly vertical, discontinuous fractures terminate at stylolites, or pinchout locally into tight carbonate matrix, and contain appreciable amounts of dead oil and calcite cement. In zones of particularly intense stylolitization, fracturing may be locally pervasive, giving the rock a brecciated appearance. Together, the stylolites and stylolite-related fractures form the primary permeability system ofthe Hanifa reservoir. This fracture system architecture is critical to understanding the production characteristics of the reservoir, which include anomalously high fluid flow in low porosity zones or transition zones between high and low porosity, radial flow behavior from well tests, smaller than expected differences in well productivity between vertical and horizontal wells, and limited injection water breakthrough.

  4. Beamlet based direct aperture optimization for MERT using a photon MLC

    SciTech Connect (OSTI)

    Henzen, D. Manser, P.; Frei, D.; Volken, W.; Born, E. J.; Joosten, A.; Lössl, K.; Aebersold, D. M.; Chatelain, C.; Fix, M. K.; Neuenschwander, H.; Stampanoni, M. F. M.

    2014-12-15

    Purpose: A beamlet based direct aperture optimization (DAO) for modulated electron radiotherapy (MERT) using photon multileaf collimator (pMLC) shaped electron fields is developed and investigated. Methods: The Swiss Monte Carlo Plan (SMCP) allows the calculation of dose distributions for pMLC shaped electron beams. SMCP is interfaced with the Eclipse TPS (Varian Medical Systems, Palo Alto, CA) which can thus be included into the inverse treatment planning process for MERT. This process starts with the import of a CT-scan into Eclipse, the contouring of the target and the organs at risk (OARs), and the choice of the initial electron beam directions. For each electron beam, the number of apertures, their energy, and initial shape are defined. Furthermore, the DAO requires dose–volume constraints for the structures contoured. In order to carry out the DAO efficiently, the initial electron beams are divided into a grid of beamlets. For each of those, the dose distribution is precalculated using a modified electron beam model, resulting in a dose list for each beamlet and energy. Then the DAO is carried out, leading to a set of optimal apertures and corresponding weights. These optimal apertures are now converted into pMLC shaped segments and the dose calculation for each segment is performed. For these dose distributions, a weight optimization process is launched in order to minimize the differences between the dose distribution using the optimal apertures and the pMLC segments. Finally, a deliverable dose distribution for the MERT plan is obtained and loaded back into Eclipse for evaluation. For an idealized water phantom geometry, a MERT treatment plan is created and compared to the plan obtained using a previously developed forward planning strategy. Further, MERT treatment plans for three clinical situations (breast, chest wall, and parotid metastasis of a squamous cell skin carcinoma) are created using the developed inverse planning strategy. The MERT plans are compared to clinical standard treatment plans using photon beams and the differences between the optimal and the deliverable dose distributions are determined. Results: For the idealized water phantom geometry, the inversely optimized MERT plan is able to obtain the same PTV coverage, but with an improved OAR sparing compared to the forwardly optimized plan. Regarding the right-sided breast case, the MERT plan is able to reduce the lung volume receiving more than 30% of the prescribed dose and the mean lung dose compared to the standard plan. However, the standard plan leads to a better homogeneity within the CTV. The results for the left-sided thorax wall are similar but also the dose to the heart is reduced comparing MERT to the standard treatment plan. For the parotid case, MERT leads to lower doses for almost all OARs but to a less homogeneous dose distribution for the PTV when compared to a standard plan. For all cases, the weight optimization successfully minimized the differences between the optimal and the deliverable dose distribution. Conclusions: A beamlet based DAO using multiple beam angles is implemented and successfully tested for an idealized water phantom geometry and clinical situations.

  5. Tracer Methods for Characterizing Fracture Creation in Enhanced...

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

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

  6. A Simple, Fast Method of Estimating Fractured Reservoir Geometry...

    Open Energy Info (EERE)

    Fractured Reservoir Geometry from Tracer Tests Abstract A simple method of estimating flow geometry and pore geometry from conservative tracer tests in single phase geothermal...

  7. Dispersed Fluid Flow in Fractured Reservoirs- an Analysis of...

    Open Energy Info (EERE)

    Dispersed Fluid Flow in Fractured Reservoirs- an Analysis of Tracer-Determined Residence Time Distributions Jump to: navigation, search OpenEI Reference LibraryAdd to library...

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

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

    Reservoirs Imaging, Characterizing, and Modeling of Fracture Networks and Fluid Flow in EGS Reservoirs Project objectives: Improve image resolution for microseismicimaging and...

  9. Elastic properties of saturated porous rocks with aligned fractures

    E-Print Network [OSTI]

    2003-12-02

    of fluid properties on seismic characteristics. ... C. C. A . The host rock is permeated by a set of parallel fractures which are ..... Similar behaviour is ..... Page 14 ...

  10. Shale Gas Application in Hydraulic Fracturing Market is likely...

    Open Energy Info (EERE)

    on unconventional reservoirs such as coal bed methane, tight gas, tight oil, shale gas, and shale oil. Over the period of time, hydraulic fracturing technique has found...

  11. Seismic velocity and Q anisotropy in fractured poroelastic media

    E-Print Network [OSTI]

    A poroelastic medium with embedded aligned fractures exhibits significant attenuation and dispersion effects due to this mechanism, which can properly be

  12. Seismic velocity and Q anisotropy in fractured poroelastic media

    E-Print Network [OSTI]

    Juan E. Santos

    2014-05-29

    medium with embedded aligned fractures exhibits significant attenuation and dispersion effects due to this mechanism, which can properly be represented at the ...

  13. INJECTION AND THERMAL BREAKTHROUGH IN FRACTURED GEOTHERMAL RESERVOIRS

    E-Print Network [OSTI]

    Bodvarsson, Gudmundur S.

    2012-01-01

    and Pruess, K. , Analysis of injection testing of geothermalreservoirs: Geothermal Resoures Council, Vol. 4. , (into a fractured geothermal reservoir: Transactions, Vol. 4,

  14. Evaluation of subsurface fracture geometry using fluid pressure...

    Open Energy Info (EERE)

    Evaluation of subsurface fracture geometry using fluid pressure response to solid earth tidal strain Jump to: navigation, search OpenEI Reference LibraryAdd to library Report:...

  15. Integrated 3D Acid Fracturing Model for Carbonate Reservoir Stimulation 

    E-Print Network [OSTI]

    Wu, Xi

    2014-06-23

    and illustrates the application of the approach with examples. The results from this study show that the new model can successfully design and optimize acid fracturing treatments....

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

    Open Energy Info (EERE)

    Conference Paper: Reservoir-Scale Fracture Permeability in the Dixie Valley, Nevada, Geothermal Field Abstract Borehole televiewer, temperature, and flowmeter datarecorded in...

  17. Determination Of The Orientation Of Open Fractures From Hydrophone VSP

    E-Print Network [OSTI]

    Lee, Jung Mo

    1995-01-01

    Open fractures are of interest in many areas such as ground water contamination, hazardous waste disposal, oil and gas recovery, and geothermal energy extraction. In

  18. Carbon Dioxide Geological Sequestration in Fractured Porous Rocks

    Office of Scientific and Technical Information (OSTI)

    Training and Research on Probabilistic Hydro-Thermo-Mechanical Modeling of Carbon Dioxide Geological Sequestration in Fractured Porous Rocks Gutierrez, Marte 54 ENVIRONMENTAL...

  19. Advanced Hydraulic Fracturing Technology for Unconventional Tight Gas Reservoirs

    SciTech Connect (OSTI)

    Stephen Holditch; A. Daniel Hill; D. Zhu

    2007-06-19

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

  20. Studies of Transport Properties of Fractures: Final Report

    SciTech Connect (OSTI)

    Stephen R. Brown

    2006-06-30

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

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

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

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

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

    Open Energy Info (EERE)

    rocks in order to better understand the fracturing system. - Utilize soft computing to process and analyze the passive seismic data. Awardees (Company Institution) University...

  3. Seepage into drifts in unsaturated fractured rock at Yucca Mountain

    E-Print Network [OSTI]

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

    1998-01-01

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

  4. Scale-Dependent Fracture-Matrix Interactions and Their Impact...

    Office of Scientific and Technical Information (OSTI)

    Scale-Dependent Fracture-Matrix Interactions and Their Impact on Radionuclide Transport: Development of efficient particle-tracking methods Citation Details In-Document Search...

  5. Fracture Evolution Following a Hydraulic Stimulation within an...

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

    Fracture Evolution Following a Hydraulic Stimulation within an EGS Reservoir presentation at the April 2013 peer review meeting held in Denver, Colorado. flowevolutionpeer2013.pd...

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

    Open Energy Info (EERE)

    Microseismicity, stress, and fracture in the Coso geothermal field, California Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Microseismicity,...

  7. Using supercritical carbon dioxide as a fracturing fluid

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

    and develop models to compare different working models of hydraulic fracturing for shale gas and oil production. Laboratory researchers have published a paper in Applied...

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

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

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

  9. Characterization of subsurface fracture patterns in the Coso...

    Open Energy Info (EERE)

    of subsurface fracture patterns in the Coso geothermal reservoir by analyzing shear-wave splitting of microearthquake seismorgrams Jump to: navigation, search OpenEI Reference...

  10. Characterization Of Fracture Patterns In The Geysers Geothermal...

    Open Energy Info (EERE)

    Characterization Of Fracture Patterns In The Geysers Geothermal Reservoir By Shear-Wave Splitting Jump to: navigation, search OpenEI Reference LibraryAdd to library Report:...

  11. Identification of MHF Fracture Planes and Flow Paths- a Correlation...

    Open Energy Info (EERE)

    creation of flow paths through the rock between two wellbores. To date, circulation systems have only been created by drilling one wellbore, hydraulically fracturing the well...

  12. Tracer Methods for Characterizing Fracture Stimulation in Enhanced...

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

    Tracer Methods for Characterizing Fracture Stimulation in Enhanced Geothermal Systems (EGS); 2010 Geothermal Technology Program Peer Review Report Tracer Methods for Characterizing...

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

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

    & Publications Tracer Methods for Characterizing Fracture Stimulation in Enhanced Geothermal Systems (EGS); 2010 Geothermal Technology Program Peer Review Report Tracer Methods...

  14. Fracture Characterization in Enhanced Geothermal Systems by Wellbore...

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

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

  15. Finite-element harmonic experiments to model fractured induced ...

    E-Print Network [OSTI]

    santos

    Mar 10, 2014 ... Fractured hydrocarbon reservoirs have been the subject of interest in explo- ... since these factors control hydrocarbon production [2]. This is ...

  16. Simultaneous usage of pinhole and penumbral apertures for imaging small scale neutron sources from inertial confinement fusion experiments

    SciTech Connect (OSTI)

    Guler, N.; Volegov, P.; Danly, C. R.; Grim, G. P.; Merrill, F. E.; Wilde, C. H. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545 (United States)

    2012-10-15

    Inertial confinement fusion experiments at the National Ignition Facility are designed to understand the basic principles of creating self-sustaining fusion reactions by laser driven compression of deuterium-tritium (DT) filled cryogenic plastic capsules. The neutron imaging diagnostic provides information on the distribution of the central fusion reaction region and the surrounding DT fuel by observing neutron images in two different energy bands for primary (13-17 MeV) and down-scattered (6-12 MeV) neutrons. From this, the final shape and size of the compressed capsule can be estimated and the symmetry of the compression can be inferred. These experiments provide small sources with high yield neutron flux. An aperture design that includes an array of pinholes and penumbral apertures has provided the opportunity to image the same source with two different techniques. This allows for an evaluation of these different aperture designs and reconstruction algorithms.

  17. Variational fracture mechanics The fracture pattern in stressed bodies is defined through the minimization of a two-field pseudo-spatial-

    E-Print Network [OSTI]

    Segatti, Antonio

    Variational fracture mechanics The fracture pattern in stressed bodies is defined through-deviatoric and masonry-like fractures. Remarkably, this latter formulation rigorously avoid material overlapping., Francfort, G. A. and J. J. Marigo, Numerical experiments in revisited brittle fracture. J. Mech. Phys

  18. Slanted annular aperture arrays as enhanced-transmission metamaterials: Excitation of the plasmonic transverse electromagnetic guided mode

    SciTech Connect (OSTI)

    Ndao, Abdoulaye; Salut, Roland; Baida, Fadi I.; Belkhir, Abderrahmane

    2013-11-18

    We present here the fabrication and the optical characterization of slanted annular aperture arrays engraved into silver film. An experimental enhanced transmission based on the excitation of the cutoff-less plasmonic guided mode of the nano-waveguides (the transmission electron microscopy mode) is demonstrated and agrees well with the theoretical predicted results. By the way, even if it is less efficient (70%???20%), an enhanced transmission can occur at larger wavelength value (720?nm–930?nm) compared to conventional annular aperture arrays structure by correctly setting the metal thickness.

  19. Seismic scattering attributes to estimate reservoir fracture density : a numerical modeling study

    E-Print Network [OSTI]

    Pearce, Frederick D. (Frederick Douglas), 1978-

    2003-01-01

    We use a 3-D finite difference numerical model to generate synthetic seismograms from a simple fractured reservoir containing evenly-spaced, discrete, vertical fracture zones. The fracture zones are represented using a ...

  20. Analyzing Aqueous Solution Imbibition into Shale and the Effects of Optimizing Critical Fracturing Fluid Additives 

    E-Print Network [OSTI]

    Plamin, Sammazo Jean-bertrand

    2013-09-29

    Two methods of hydraulic fracturing most widely utilized on unconventional shale gas and oil reservoirs are “gelled fracturing” and “slick-water fracturing”. Both methods utilize up to several million gallons of water-based fluid per well in a...