Simulation of Flow Field of Solution Mining Salt Cavities for Underground Gas Storage

Salt cavern solution mining is a complicated process of fluid dynamics and chemical dynamics, including salt boundary dissolution, cavern expansion, brine flow, and species transport. The reaction processes occur simultaneously and interact with each other. In this study, a multiphysical coupled model is established to evaluate the real-time three-dimensional salt cavern shape expansion, the velocity field, and the brine concentration distribution. Then, the predicted results are compared with the field data of a Jintan Gas Storage Well in China. The average relative deviations with the turbulent flow are 5.7% for outlet brine concentration and 4.0% for cavern volume. The results show that salt cavern can be divided into four regions, including the shock region, plume region, reflow region, and suction region. The results also indicate that the turbulent flow will stimulate the formation of the vortex, thus affecting the distribution of brine concentration. And, the brine concentration distribution primarily influences cavern corrosion. The results suggest that adjusting the inject velocity and the tube position can change the cavern construction rate and the cavern shape. Overall, these results have guiding significance for the design and engineering practice of salt cavern construction for energy storage.