Tightness Analysis of Anhydrite Mine-Out Used for Underground Crude Oil Storage Considering Seepage–Stress Coupling: A Case Study

Good tightness is one of the necessary conditions for an anhydrite mine-out space to be used underground crude oil storage. Combining engineering geological surveys, laboratory tests, and numerical simulations, this paper quantitatively analyses Anhui Hengtai under different working discusses its suitability Triaxial compression tests rock considering seepage were carried out study hydraulic mechanical characteristics during failure. The permeability coefficient–strain empirical formula was constructed. A simulation on basis finite difference method surrounding after excavation 0.2 MPa, 0.6 1.0 MPa storage pressures, respectively. results showed that coefficient increased with increasing pressure, growth rate gradually slowed pressure reached a certain value. Overall, had good tightness, small. This demonstrated feasibility using provides scientific site selection