Long-term operational stability analysis of underground storage in horizontal salt cavern with interlayer

A rock salt cavern is an ideal underground energy storage. Most rock salt deposits in China are thin-layered deposits with interlayers. Therefore, we suggest horizontal rock salt caverns because of much larger storage volumes. Taking the ellipsoidal horizontal single-cavern and double-caverns in rock salt with a single interlayer in the cavern middle as examples, the natural gas storage models were simulated by COMSOL three-dimensional software. The changes of vertical and horizontal displacement, volume convergence and stress-strength-ratio distribution in with different diameter-to-height ratios (N = 1.5, 2.0, 2.5 and 3.0) and operation times (t = 5, 10, 15, 20 years) were analyzed, and the optimal diameter-to-height ratio of N = 2.5 and the optimal pillar width of 100m were determined.