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U.S. Department of Energy
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Mechanical behavior of Mesaverde shale and sandstone at high pressure

Technical Report ·
OSTI ID:6124515

Rock mechanics measurements taken on Mesaverde shale (source rock) and sandstone (reservoir rock) from about 350-m depth (Colorado) and 1600-m depth (Wyoming) are reported. For each sandstone and shale, we have determined: (1) Tensile srength parallel and perpendicular to bedding, 0.1-MPa pressure. (2) Triaxial stress failure envelope in compression to 300-MPa confining pressure, parallel and perpendicular to bedding. (3) Pressure-volume behavior to 1.2 GPa. The results for (1) indicate that, in general, the tensile strength of Wyoming sandstone is about three times that of Colorado sandstone. For both sandstones, the tensile strength is isotropic with respect to bedding. The tensile strength of both shales parallel to bedding is about 30 to 50% greater than that measured normal to bedding. The shale from Wyoming has a tensile strength about 25 to 50% greater than that from Colorado. Strengths and failure modes in compression (2) show that the transition between brittle failure and ductile deformation occurs at a confining pressure of about 0.1 GPa for the Colorado sandstone and 0.25 GPa for all other rocks tested. In Colorado, the shale is about 50 to 70% stronger than the sandstone; in Wyoming, the shale is about 20 to 30% stronger than the sandstone. The Wyoming sandstone is about 50% stronger than that from Colorado; the Wyoming shale is about 20 to 30% stronger than that from Colorado.

Research Organization:
Lawrence Livermore National Lab., CA (USA)
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
6124515
Report Number(s):
UCRL-85808; ON: DE82001665
Country of Publication:
United States
Language:
English