Relative permeability of two immiscible fluids flowing through porous media determined by lattice Boltzmann method

This article applied the multiple relaxation time multicomponent/multiphase pseudopotential lattice Boltzmann model to simulate two immiscible fluids flow in 2D porous media, and analyzed the effects of capillary number (Ca), viscosity ratio (M) and wettability on the relative permeability curves. Simulation results indicate that the nonwetting phase (NWP) relative permeability increases with increasing Ca; while the effect of Ca on the wetting phase (WP) relative permeability depends on the wettability. When M > 1, the NWP relative permeability increase with increasing M in a strong wetting condition because of the lubricating effect. The amplitude of the NWP relative permeability may even exceed the single phase permeability. However, the exact value of the amplitude and where it occurs depends on M and the structure of the porous media. The WP relative permeability is insensitive to M. When the porous media converts from strong wetting condition to neutral wetting condition, the NWP relative permeability decreases while the WP relative permeability increases.