A relative permeability model considering nanoconfinement and dynamic contact angle effects for tight reservoirs

Abstract

With a sharp reduction in conventional oil and gas resources, tight oil and gas resources have attracted great interest in the petroleum industry. Relative permeability plays an important role in modeling fluid flow in tight reservoirs. Here, considering the nanoconfinement effects (abnormal viscosity effect (AVE) and slip effect) and dynamic contact angle (DCA) effect, a relative permeability model for tight reservoirs is proposed. The results show that the proposed model can accurately describe the relative permeability in tight reservoirs. As the AVE of water or oil increases, the relative permeability of water decreases, while the relative permeability of oil hardly changes for rocks with an average pore radius of 298 nm and decreases for the ones with an average pore radius of 49 nm. As the slip length of oil increases, the relative permeabilities of both water and oil decrease. As the DCA effect increases, the relative permeability of water increases, while the relative permeability of oil is unchanged. With a decrease in the pore size, the nanoconfinement effects on relative permeability become more notable, while the DCA effect on relative permeability becomes smaller. This work is of great significance to the development of tight reservoirs.