Gas productivity analysis of high speed non-Darcy flow in deformed media gas reservoir

The gas producivity is infuluenced by many factors. In the routine calculation of gas productivity, many factors were negelected for convenience such as the non-Darcy flow, the changes of gas PVT parameters and the deformation of rock media. In order to analysis the effect of these factors on gas productivity, the mathematical model of high speed non-Darcy unstable flow in deformed media gas reservoir, which takes the changes of PVT of real gas with pressure into consideration, has been made in this paper. Numerical difference technology is used to find solution to the mathematical model,in which there is a well in the center of the round closed layer and the well bottom hole pressure is kept as constant in the production. And the effect of the factors on the gas productivity is analyzed. The results show that the influences of porosity changes caused by media deformation to productivity can be neglected, the changes of permeability can lead to the decreasing of productivity in the early period. And the productivity under the conditions of the high-speed non-Darcy flow and the changes of gas PVT is higher than the one when the gas flow is linear and PVT of gas is constant. These research results are meaningful to predict the gas productivity accurately.