Impact of injection-withdrawal thermal effects on the operating pressure and optimization of salt cavern gas storage

• Thermo-mechanical model predicts cavern stress and 12.75°C thermal change • Sonar data confirm 5.1 % cavern volume shrinkage over seven years • Coupled thermal–creep analysis ensures long-term cavern stability • Lowering minimum pressure to 9 MPa improves safety and economics • Framework aids design of large-scale subsurface energy storage systems The safe and efficient operation of large-scale underground energy storage systems is increasingly critical for stabilizing energy supply in integrated power grids. This study presents a thermo-mechanical coupling model to investigate temperature-induced stress responses and creep deformation during gas injection and withdrawal in salt caverns. Using the Salt Cavern Gas Storage as a case study, we quantify temperature fluctuations (up to 12.75°C) and evaluate their influence on stress redistribution and cavern deformation. The model couples real-time temperature and pressure data with creep constitutive behavior to simulate cavern volume contraction and principal stress evolution. Sonar survey comparisons confirm that the observed 5.1% volumetric contraction aligns closely with simulation results. Under extreme emergency withdrawal conditions, the maximum principal compressive stress remains within safe margins without entering the tensile stress domain. Our findings suggest that reducing the minimum operating pressure from 10 MPa to 9 MPa can improve economic efficiency without compromising structural integrity. This research provides insights into the thermal management and mechanical safety of subsurface energy storage systems, which are vital for the design and long-term stability of large-scale power sources.