Pore characteristics and nonlinear permeability model of salt rocks with interlayers

In order to identify the sealing capacity and safety between cavities or between cavity and fault, it is necessary to study the sealing capacity and permeability of the interlayers and salt rocks of salt cavern gas storages, and to identify the risk of seepage between cavities or between cavity and fault. In this paper, the pore structures of interlayers and salt rocks were analyzed based on the geological conditions in Jintan area. Then the nonlinear seepage model of gas permeability was established, and it considers the effects of gas-solid molecular force and diffusion on gas seepage. Finally, this model was applied in Jintan Gas Storage to analyze the sealing capacity between adjacent cavities with interlayers in pillars, and investigate the situations of the faults around the cavities. Salt rocks are very good choice for the site of underground gas storage due to its good sealing capacity, but the gas permeability of mudstone interlayers is relatively obvious. So it is of great significance to the solution mining of salt rocks with interlayers and the optimization and determination of the distance between the cavities or between cavity and fault.