A Novel Transient Pressure Analysis Model for Horizontal Well in Gas Reservoir with Finite Water Bodies

Bottom water is regarded as infinite rigid water body in common bottom water gas reservoir well test model and the water body size is not taken into account, aiming at this problem, using Green's function and potential superposition method, horizontal well pressure performance model for bottom water gas reservoir with finite water bodies is developed and solved. Typical pressure response curve is obtained by numerical inversion and divided into 6 main flowing stages, and the influence of water body multiples on pressure response is analyzed. The results show that when the water body multiples are 0 or tend to infinity, the results obtained in this paper are consistent with those of conventional top–bottom closed gas reservoir model or infinite rigid bottom-water gas reservoir model, respectively, and the pressure dynamic of reservoir with finite water body falls in between. As the multiples of water body increase, the longer the hemispherical flow lasts, the later the late pseudo radial flow appears, and the lower the pressure derivative value is, till late pressure derivatives go down completely for infinite water body.