Time-dependent deformation of Wufeng-Longmaxi shale and its implications on the in situ state of stress

The stress-strain relationship in shales is generally time-dependent. This concerns their long-term deformation unconventional reservoirs, and its influence on the situ stress state therein. paper presents an experimental investigation time-dependent of Longmaxi shale gas shale. A series creep experiments subject samples to long-term, multi-step triaxial compression. It found that exhibit varying degrees deformation, which can be adequately described by a power-law function time. results establish between elastic Young’s modulus viscoplastic constitutive parameters, are different from previous those derived North American shales. Based this model, relaxation differential accumulation over geologic time scales estimated. linear elasticity substantially overestimates predicted context relaxation. characterized viscoplasticity vital importance for various geomechanical problems reservoirs.