Discussion on the no cushion gas technology of salt-cavern gas storage

In the operation process of salt-cavern gas storage, cushion gas can never be recovered, which increases the engineering construction cost of gas storage and decreases its economic benefit. A cushion gas free technology of salt-cavern gas storage was put forward based on the gas injection & brine discharge technologies and experience of salt-cavern gas storage. Then, the cushion gas free operation mode was compared with the conventional operation mode from the aspects of gas storage operation mode, cavity utilization rate, construction cost, construction geological threshold and long-term cavity stability. Finally, taking two gas storages as the typical representatives, storage construction cases in thin salt beds and deep salt beds by means of two different technologies was compared. It is indicated that the cushion gas free technology can greatly increase the cavity utilization rate of salt-cavern gas storage, significantly decline its engineering construction cost, decrease its construction geological threshold and promote the long-term stable operation of cavity. The research results can bring better benefits to the construction of salt-cavern gas storages in China.