Mechanical behavior and constitutive model of shale under real-time high temperature and high stress conditions

Abstract The high temperature and in-situ stress geological environment can significantly affect the mechanical properties, failure modes, deformation characteristics of deep shale reservoirs. In this study, real-time triaxial compressive tests simulating formation (temperature: 25–150 °C, confining pressure: 0–100 MPa) are carried out. GSI-strength degradation constitutive models derived based on Hoek–Brown criterion. results show that in low pressure conditions, behavior is greatly influenced by temperature. Compared with at 25 strength 150 °C decreases up to 13.7%, elastic modulus 36.9%. peak strain was increased a factor 1.4, yield level advanced as much 7.4%. However, plasticity enhanced mode relatively single. model well characterize variation law under conditions. statistical damage matches actual stress–strain curve very well, it fully reflect shale. findings study help us better understand properties