Evaluation of Gas Injection Capacity of Gas Injection Wells in Reservoir-Type Gas Storage

In view of the problems of large error and lack of theoretical basis in the conventional evaluation methods for the gas injection capacity of gas injection wells in reservoir-type gas storage, under the condition of pseudo-steady seepage, it is assumed that the formation is horizontally homogeneous and of equal thickness, the gas injection well is located in the center of the formation, the injected gas flows isothermally and the injection rate is stable. Based on the gas isothermal compressibility coefficient, considering both formation skin factor and flow skin factor, the gas injection capacity evaluation equation of gas injection wells in reservoir-type gas storage is derived. The formation inspiratory index of reservoir gas storage is defined and calculated theoretically according to formation pressure, and its accuracy is verified by nitrogen test injection and natural gas actual injection data. Comprehensive comparison and verification show that the calculation results of theoretical calculation, nitrogen test injection calculation and natural gas actual injection calculation are within the range of engineering error, which indicates that the derived evaluation method for gas injection capacity of gas injection wells of reservoir-type gas storage has high credibility and can be popularized and applied to the evaluation of gas injection capacity of other reservoir-type gas storages.