Construction key technologies and challenges of salt-cavern gas storage in China

The construction course of salt-cavern gas storage in China is divided into three stages, i.e., technology research and exploration, technology digestion and formation, and technology maturity and development. In the process of salt-cavern gas storage construction, a number of distinguished technologies are developed, such as old cavern rebuilding, gas leak detection of cavern, oil-brine interface monitoring based on optical fiber and high-efficiency gas injection debrining. In this paper, a complete set of system and technologies was developed to monitor wellhead temperature and pressure, ground subsidence, cavity shape and wellbore integrity in the process of injection and production to ensure the safe and stable operation of salt-cavern gas storage. The problems involved in the construction of salt-cavern gas storage were described, such as slow solution mining, difficult old cavern rebuilding and fewer sites available for gas storage building, and it was demonstrated that existing technologies can't meet the construction requirements of salt-cavern gas storage in layered salt beds in China. To cope with the technological challenges in the process of salt-cavern gas storage construction, a series of research contents were proposed correspondingly, and the technology development direction of salt-cavern gas storages in China was pointed out.