... coefficient “n” such that se=s c -nPp. Reservoir Characterization pore pressure composition assumption effective stress coefficient Upstream Oil & Gas biot poroelastic coefficient horizontal stress tectonic strain compressibility effective pressure coefficient Biot coefficient...

... Abstract Granular porous material is idealized as an elastic-plastic material, where macroscopic failure occurs at a critical stress by localized dilatant shear at low effective pressure and compactional cataclastic flow at high effective pressure. Yielding and accumulation of microscopic...

....) that control the brittle-ductile transition and their dependence on temperature are not well-understood. In this study, we deformed porous Indiana limestone samples with initial porosity of ~16% at temperatures of 298, 323 and 348 K under effective pressures ranging from 10 to 50 MPa. In each deformation test...

... temperatures (in the range -30°C and 80°C) and at different effective pressures (from 1.2 MPa up to 8 MPa). Experimental results showed that the elastic wave velocities measured are strongly dependent on temperature (mainly through the viscosity) whereas little effect of effective pressure was observed...

... reservoir geomechanics triaxial loading St Peter quartz sand Upstream Oil & Gas LABORATORY study experiment structural geology mechanism effective pressure envelope quartz sand hydrothermal deformation deformation Reservoir Characterization Chester strength sensitivity...

... effective pressure maintenance resulting from waterflooding. The total stresses and pore pressure data can be combined in terms of mean effective stress, P', and stress difference, Q, as shown in Fig. 4., where: P' = [(Sovb + Shmax + Shmin)/3] Pres (6) Q = (Shmax Shmin) (7) Effective stress magnitudes...

.... Fluid Dynamics variation Abstr exponentially flow in porous media thermally thermal cycle temperature Upstream Oil & Gas Geophy pore pressure reservoir porosity effective porosity transport property logarithm permeability maximum thermal cycle temperature effective pressure MPa...

... model equation reservoir geomechanics effective pressure assumption gas gun experiment liquifaction limestone sample experiment Upstream Oil & Gas limestone stress wave pore water pressure shear strength experimental data stress-strain curve Rock Mechanics Contributions...

... by an increase in confining pressure since inelastic deformation by homogeneously distributed crystal plasticity can occur at room temperature (e.g. Fredrich et al. 1989). In low porosity silicate rocks at effective pressures accessible in the laboratory, elevated temperatures are required to activate...

... ABSTRACT ABSTRACT: The response of shale to indentation and triaxial testing under a range of total and effective pressures, at low and high displacement rates, has been examined. At low rates, effective pressure controls both processes, but at high rates, indentation is controlled...

...) = ( 2_r2)« , and (1) c (r) 2 (l-v) r g(t) dt = G (t2_r2)% (2) where Pe(r) is the radially symmetric effective pressure distribution, is Poisson's ratio, G is the shear modulus of the surrounding rock, r is the radial coordinate, and (r) is the fracture aperture. These equations along with the closure...

... and an effective pressure of 100 HPa. The strength of the gouge decreased with increasing pore pressure to 50 HPa and then was nearly constant between 50 and 125 HPa. The samples at 50-125 NPa pore pressure slid stably, whereas those at 3-25 HPa pore pressure showed stick-slip behavior. Lengthening the pre-heating...

... Upstream Oil & Gas effective pressure dry specimen microfracture reservoir geomechanics Friedman deformation mechanism wet specimen Reservoir Characterization van der molen specimen pe 50 strength partial melting grain boundary granodiorite MPa texture Chapter 29 DEFOR...

... range. Test results both of field and laboratory were expressed as the 769 770 ISSUES IN ROCK MECHANICS relation of flow versus effective pressure. A brief description of these tests and the analysis and conclusions follow. LABORATORY TESTS A simple device similar to a soil permeameter, was used...

...EFFECTS OF WATER-SATURATION ON STRENGTH AND DUCTILITY OF THREE IGNEOUS ROCKS AT EFFECTIVE PRESSURES TO 50 MPA AND TEMPERATURES TO PARTIAL MELTING S. J. Bauer, M. Friedman, and J. Handin Center for Tectonophysics Texas A&M University College Station, TX 77843 INTRODUCTION Energy extraction from...

...PHYSICAL EFFECTS IN ROCK UNDER NEGATIVE EFFECTIVE PRESSURES: SOUND SPEEDS AND HYDRAULIC D1FFUSIVITY T. J. Shankland and P.M. Halleck Geophysics Group Los Alamos National Laboratory Los Alamos, New Mexico, 87545 New engineering techniques such as com- pressed air or pumped hydro energy storage...

... and grain contacts. The large variation in porosity and permeability at low effective pressures in highly porous rocks is due to the stress concentrations at the grain contacts. The smaller porosity-pressure and permeability- pressure variation for low porosity rocks is due to the blunting of the stress...