Water soluble performance and solution mining countermeasures of salt-cavern gas storages with complex lithologies

The construction of salt-cavern underground gas storages in China is faced with the problem of complex geological conditions, so the selection of UGS construction areas and intervals is the base of efficient construction of salt-cavern UGS. Taking four salt-cavern UGS (Pingdingshan, Huaian, Anning and Chuzhou) as the research objects, this paper tested and analyzed the water-soluble compositions of the cores of different UGS construction areas, UGS construction intervals and lithological characteristics and summarized the water soluble performance of their UGS construction formations. Then, the influence factors of solution mining in different areas were analyzed, and the corresponding UGS construction countermeasures were proposed as follows. First, as for Pingdingshan UGS, it is necessary to strengthen the control and prediction of interlayer collapse. Second, as for Huaian UGS, the technology of horizontal well shall be adopted to evade thick interlayers. Third, as for Anning UGS, scale control and removal measures shall be taken to alleviate the adverse impact of pipe scaling on the engineering. Fourth, as for Chuzhou UGS, it is recommended to expand the storage capacity by increasing residue’s effective space utilization rate.