Calculation method for effective gas storage space of gas storage

The invention discloses a method for calculating an effective gas storage space of a gas storage. The method comprises the following steps: S1, establishing a three-dimensional geologic model of the gas storage; s2, coarsening the grid system; s3, preparing numerical simulation basic parameters; s4, obtaining a relative permeability curve; s5, PVT parameters are obtained; s6, establishing a gas storage numerical simulation model; s7, performing whole-process history fitting on the numerical simulation model of the gas storage; s8, carrying out zone division on the gas storage based on the critical saturation parameter; s9, extracting the pore volume of the gas storage; s10, determining the utilization efficiency of each permeation zone of the gas storage; and S11, determining the effective gas storage space of the gas storage. By adopting the method, the effective gas storage space of the reservoir can be accurately determined when the exhausted oil and gas reservoir is reconstructed into the gas storage, and