Experimental Study on the Seepage Characteristics of Multilayer Commingled Production and Influencing Factors of the Development Effect in Low-Permeability Tight Sandstone Gas Reservoirs.

Abstract

For low-permeability tight sandstone gas reservoirs, multilayer commingled production technology is usually adopted by a large number of production wells. This production method can significantly increase the productivity of a single well, thereby improving the efficiency of gas field development. To have a better understanding of the seepage characteristics of multilayer commingled production of the SXM (ShaXiMiao) Formation tight sandstone gas reservoirs, an indoor physical simulation experiment of commingled injection and separate production using double-pipe parallel long cores was designed under influencing factors such as formation pressures, permeability contrast, and water saturations. Finally, the contribution of high- and low-permeability reservoirs to the total production capacity under different conditions is clarified, which provides a reference for formulating reasonable development strategies for gas reservoirs. Through the experimental study, we found that the recovery degree of the high-permeability formation is higher than that of the low-permeability formation during the depletion production process. The combination of depletion development and water flooding can greatly increase the recovery degree of gas reservoirs. Under the same production pressure difference condition, the higher the formation pressure and the permeability, the higher the production capacity. If the water saturation increases, the production contribution rate of the high-permeability layer gradually increases, and the production contribution rate of the low-permeability layer gradually decreases.