Abstract: The tightness analysis of salt cavern as energy storages is very important to underground energy storage construction project. In the salt mine of China, the salt layers are usually intersected by many indissoluble or slightly soluble interlayers. Considering these sedimentary characteristics, a series of experiments concerning the tightness of the salt storages are carried out in Qianjiang mine of Jianghan Oilfield. In-situ tightness tests taking nitrogen as media were carried out at different key points of the testing wells; the capillary pressure tests of the overlay and interlayers were done to analyse the tightness of the carvens. Also the distribution of pore structure characteristics of the interface and interlayer were observed by the scanning electron microscopy (SEM); it is found that the salt rock has characteristics of big size of crystal particles, compact surface and good sealability; and small particles of mudstone can fill the gap very well at the interface; and the two types of rock are cemented completely. The results illustrate that entire tightness of salt rock in Qianjiang mine is very suitable for the construction of underground energy storage. The indoor and in-situ experiments have great reference value and practical significance for the research of underground energy storage construction project.

Key words: bedded salt rocks, energy storage, tightness, experimental study