Research on the Intelligent Allocation Method of Injection and Production Wellbores for Salt-Cavern Compressed Air Energy Storage under the Dual Constraints of Safety and Economy

The intelligent operation and maintenance of gas injection and production in salt-cavern compressed air energy storage means adjusting or optimizing the gas injection and production plan in real-time according to the volume of injected and produced gas under the premise of safety and economy. The key is how to optimize the wellbore allocation plan for gas injection and production. Therefore, based on the improved random forest algorithm and the gas injection and production conditions, this paper establishes an improved random forest algorithm to obtain a set of wellbore allocation plans with a priority order. In combination with the cutting particle motion model and the pressure-flow prediction model for gas injection and production, constraints are set on the cutting-carrying size, erosion flow rate, and minimum injection and production flow rate. An intelligent allocation solution algorithm for injection and production wellbores of salt-cavern compressed air energy storage under the dual constraints of safety and economy is established, and a case analysis is conducted to prove the necessity of the model. Furthermore, the impacts of economic constraints, total gas injection and production volume, wellbore diameter, and injection and production media on the wellbore allocation for injection and production are explored. The research results show that ① The wellbore allocation results obtained from the model established in this paper can avoid safety hazards and economic losses during the gas injection and production process, enabling the gas storage reservoir to operate more stably and efficiently. ② The ground cutting treatment capacity has a significant impact on the injection and production wellbores, and it is necessary to select appropriate equipment for ground cutting treatment. ③ As the total planned volume of gas injection and production increases, more injection and production wells are required. The maximum flow rate of a single wellbore in the overall gas injection condition decreases, and the maximum flow rate of a single wellbore in the overall gas production condition also decreases. Moreover, the larger the size of the injection and production wellbores, the higher the priority of their allocation. The wellhead pressure is not affected by the above factors. ④ Gases with a relatively low gas density as the injection and production medium will require more injection and production wells during the injection and production process. The flow rate of a single injection and production well is larger; the cutting-carrying size is larger, and a higher wellhead pressure is needed. The research results can provide theoretical guidance for the accurate prediction of the intelligent allocation method of injection and production wellbores in salt-cavern compressed air energy storage and contribute to ensuring the safe, economic, and efficient operation of salt-cavern gas storage reservoirs in China.