Interlayer treatment process in cavity building for salt cavern gas storage - A case study of Jintan Gas Storage of West-to-East Gas Pipeline

In China, the cavity building interval for salt cavern gas storage often features complicated lithology, and interlayers with varying thickness (from 1 m to 10 m or more) exist at different depths, leading to distinct results of cavity building result. Taking the 8 cavity building wells of Jintan Gas Storage as an example, through analyzing the cavity building parameters, and studying the cavity building effect under different interlayer treatment process, the cavity building solution for multi-interbedded salt rock is proposed: (1) the OWC is kept at least 3-4 m above the interlayer; (2) when the OWC is under the interlayer, the oil cushion thickness is controlled less than 0.1 m and cavern roof diameter should not be too big; (3) when the OWC is under the interlayer and the cavern needs to be expanded, the OWC is adjusted above the interlayer; and (4) when the interlayer beneath the cavern is treated, the inner pipe should be located under the interlayer or at least at the interlayer position. The solution can provide a reference and technical support for other salt cavern gas storage building.