Feasibility study on transformation of abandoned salt caverns into underground gas storage in China

The transformation of abandoned salt caverns from salt-production industries into Underground Gas Storages(UGS) has a great significance for the full utilization of salt mine resources and accelerating the construction of UGS. The abandoned salt caverns can save a lot of construction time for gas storage and obtain faster gas injection-production application and economic effect. At the same time, this work can reduce the complex safety risks such as brine leakage, land subsidence and collapse caused by the long-term deformation of the cavern. In China, it has a long history of salt production, widely distributed salt mines, and a large number of abandoned cavities, which provide a basis for the transformation. Combined with the experience of transforming abandoned single-well cavities into gas storages in Jintan city, Jiangsu Province, this paper mainly studies the feasibility of utilization and transformation of abandoned salt cavern mined by directional butted wells in Pingdingshan city, Henan province, from the perspective of geology, engineering and economy. The results of sonar cavity measurement show that the old caverns have a single cavity volume of 300000 ~ 450000 m3, which provides big storage volume for the reconstructed salt cavern gas storage. Moreover, combined with the borehole sealing test results, the cavity well type transformation scheme of "plugging old wells and drilling renewal wells" is proposed, which has been successfully applied in directionally butted-well M5/M6. This study provides rich experience and reference for the reuse of abandoned salt cavern with directional butt wells for underground gas storages.