Study of Impact of Sediment on the Stability of Salt Cavern Underground Gas Storage

The utilization of sediment voids for natural gas storage represents the future direction of salt cavern underground gas storage (UGS) in China. In this study, we first analyzed the way in which the sediment interacts with the salt caverns and the equilibrium state of the process. Subsequently, a novel approach employing the Discrete Element Method (DEM) for simulating sediment-filled salt cavern UGS was introduced, successfully modeling the operational process of sediment-filled salt cavern UGS. Moreover, deformation, plastic zone behavior, effective volume shrinkage rate, equivalent strain, and safety factor were employed to assess the impact of sediment on salt cavern stability. The findings indicate a positive influence of sediment on salt cavern stability, particularly in regions directly contacting the sediment. Deformation and effective volume shrinkage of the cavern were effectively mitigated, significantly improving the stress state of rock salt. This effect is more pronounced at lower internal gas pressures. In summary, sediment enhances the stability of salt caverns, providing a long-term and stable environment for natural gas storage within sediment voids.