Progressive Failure Analysis of Wellbore Cement Sheaths in Salt Cavern Energy Storage Under Gas Injection–Production Cycles

Abstract In this work, we propose a computational paradigm for gas thermo-mechanical coupling in salt cavern gas storage systems within the phase-field framework. The novelty lies in integrating a thermodynamic gas-flow model with the phase-field formulations to simultaneously capture the gas pressure, temperature evolution, and the deformation–failure behavior of the cement sheath. The validation against analytical solutions, laboratory tests, and field-scale monitoring data confirms the robustness of our approach. Our simulations reveal that the gas pressure varies nearly linearly during injection–production cycles, while the temperature evolves nonlinearly with localized hot and cold zones. The failure patterns are depth-dependent: tensile damage dominates near the wellhead, whereas mixed-mode failure occurs at greater depths, which is consistent with field observations. The thermal cycling drives progressive damage and reduces heat transfer capacity in the fractured zones. The parametric studies highlight the strong influence of the lateral stress coefficient and fracture energy on critical operating pressures. Progressive injection–production strategies are recommended to enhance wellbore integrity and optimize storage capacity.