Review and outlook of space utilization technology for salt-cavern gas storage in China

Salt-cavern gas storage, characterized by the low reservoir permeability, high damage restoration capacity, high injection-production ratio, and the small amount of required cushion gas that is also fully recoverable, is found with extensive applications. However, due to the inferior quality of salt rocks, massive insoluble salt rock materials accumulate in the formed salt cavity, and a large amount of brine exists in the pores of such sediments and cannot be drained. This leads to a tremendous spatial waste of gas storage, and how to maximize the utilization of the salt cavity space is a problem demanding prompt solutions. The geology of salt layers of China’s salt-cavern gas storage and the space utilization technology for basal sediments were reviewed, which pointed out that further investigation is required for placing the brine drainage string into the base of insoluble sediments, although the gas-driven brine drainage above such sediments has increasing technical maturity. In terms of the running in and out the pipe string, the plugging problem after the string is placed and corresponding solutions, pipe diameter optimization, and future hydrogen storage, Suggestions were made to provide references for technical research on the salt-cavern gas storage space utilization in China.