The optimum interwell distance analysis of two-well-horizontal salt cavern construction

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

KEYWORDS:

• Interwell distance
• salt cavern
• leaching time
• two-well-horizontal cavern
• construction rate
• cavern expansion

Acknowledgments

The authors would like to acknowledge the financial support from the National Natural Science Foundation of China Project (Grant No. 11705255), Chinese Academy of Sciences “Light of West China” Program (Grant No. 29Y728010) and PetroChina Scientific Research and Technology Development Project (Grant No. 2019B-3205).

Additional information

Funding

This work was supported by the Chinese Academy of Sciences “Light of West China” Program [29Y728010] PetroChina Scientific Research and Technology Development Project [2019B-3205]; National Natural Science Foundation of China Project [11705255].

Notes on contributors

Fansheng Ban

Fansheng Ban, graduated from the Chinese Academy of Sciences with a PhD in 2008, majoring in fluid mechanics.

Guangjie Yuan

Guangjie Yuan, Ph.D. graduated from Shanghai Jiaotong University in 2004, majoring in machinery manufacturing.

Jifang Wan

Jifang Wan, Ph.D. graduated from PetroChina Exploration and Development Research Institute in 2020, specializing in oil and gas well engineering.