Modeling Reservoir Gas Permeability Tests for Cylindrical and Spherical Geometry

Approximate analytical models of non-stationary single and double reservoir gas permeability tests with radial flow through hollow cylindrical or hemispherical samples are developed and compared with numerical solutions of full models. The effects of compressibility and slip of gas are included. The approximate solutions are obtained assuming that the total transient mass flux is spatially homogeneous, i.e., it has constant value in direction of flow (along radius in cylindrical or spherical coordinate system). The evolutions of reservoir pressures and transient spatial distributions of pore pressure are determined and apply both for pumping and suction tests. The solutions of full model were obtained with help of the finite element method and served as references to evaluate the approximate models.