ABSTRACT

Large-scale energy is often stored in underground salt caverns. Because China has abundant thinly bedded rocksalt, two-well-horizontal (TWH) caverns are considered as alternatives for large-scale energy storage, which possess higher construction rate and larger volume than the vertical caverns. To-date, the analysis of the development of shape and the control methodology with different interwell distances of TWH caverns are not fully understood. In order to eliminate these drawbacks, TWH-cavern construction has been simulated in the current work. A platform was established based on TWHSMC V2.0 simulation code to obtain the theoretical basis for TWH-cavern leaching construction for a more user-friendly visual analysis of the cavern development. Setting cavern construction efficiency as the objective functions for optimization, a series of theoretical simulations were conducted to analyze how the interwell distance affects the TWH-cavern construction. The results obtained illustrate that the interwell distance correlates with a rapid decrease in the leaching time until a tendency to stabilization is observed. The optimum interwell distance is 115 m at a flow rate of 300–500 cubic meters per hour. The interwell distance also influences the longitudinal span of the cavern. When the interwell distance is 115 m, the cavern has the smallest span in the longitudinal span. Therefore, the potential crossing of the interlayer can be minimized, which is good for the safety of cavern.

Abbreviations: UGS: Underground gas storage; SPR: strategic petroleum reserves; CAES: Compressed air energy storage; SWV: Single-well-vertical; TWH: Two-well-horizontal; SIMPLE: Semi-Implicit Method for Pressure-Linked Equations; TWHSMC: Two-well-horizontal solution mining cavern; 2D: Two dimensional; VOF: Volume of Fluid; 3D: Three dimensional; API: American Petroleum Institute