Modeling and analyzing gas supply characteristics and development mode in sweet spots of Sulige tight gas reservoir, Ordos Basin, China

Abstract

In order to study the characteristics of the gas supply and development mode in sweet spots of Sulige tight gas reservoir in Ordos Basin, China, a mathematical model was developed for the typical lenticular reservoirs in tight gas reservoirs, and its analytical solution was obtained. The ideal model was calculated by using the analytical solution. Analysis of the production data indicated a clear boundary between the high- and low-permeability regions of the lenticular reservoir, and the boundary will supply gas to the low-permeability region. The reliability of this finding was validated by real production data. The development mode of the lenticular reservoir was obtained, that is the high-permeability area was first used during the initial production; when the pressure wave reached the boundary in the high-permeability region, the production showed a pseudo-steady state; further increase of the production pressure exceeding the threshold of the surrounding low-permeability region triggered the utilization of the low-porosity and low-permeability regions. The established model can provide useful guidance for the development of similar tight gas reservoirs.