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THERMO-ELASTOPLASTIC STUDY OF THE COLORADO SHALE BEHAVIOUR
Session: Rock Mechanics and Engineering Geology I / Mécanique des roches et ingénierie géologique I
Morteza Mohamadi, University of Calgary (Canada)
Richard Wan, University of Calgary (Canada)
The thermo-hydro-mechanical behaviour of shale has gained increasing attention in cap rock integrity assessment of fairly shallow steam injection oil recovery projects in western Canada. The paper presents an integrated experimental/constitutive study of the Colorado shale which serves as a cap rock to underlying oil-rich formations in the Cold Lake area, east-central Alberta, Canada. Results of drained thermal consolidation and isothermal triaxial compression tests at different temperatures on Colorado shale show that: 1) volume changes due to drained heating are greatly influenced by consolidation history, 2) initial elastic moduli of the tested samples decrease with elevation of temperature, and 3) the peak and post-peak failure envelopes are nonlinear and show reduced shear strength at elevated temperatures. These phenomenological mechanisms were implemented in an elastoplastic constitutive model which was used to describe the experimental data. Comparison of the experimental measurements and model calculations verify the usefulness of the model.
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