Shan-and-Chen-type multiphase lattice Boltzmann study of viscous coupling effects for two-phase flow in porous media

In this paper, the Shan–Chen-type (SC) multiphase lattice Boltzmann model was used to study the viscous coupling effects for immiscible two-phase flow in porous media. In the model, any typical equation of state can be incorporated and different contact angles of the gas–liquid interface at a solid wall can be obtained easily through adjusting the ‘density of wall’ (Benzi et al., Phys. Rev. E 2006; 74(2):021509). The viscous coupling effects due to capillary number, the viscosity ratio and the wetting angle were investigated. The two-phase flows with density ratio as high as 56 in porous media were simulated. For different viscosity ratios and wettability, two-phase flow patterns and relative-permeability curves as a function of wetting saturation were obtained. It is observed that when the wetting phase is less viscous and covers the solid surface, the relative permeability of the non-wetting phase may be greater than unity. Here, the SC model is demonstrated as a suitable tool to study the immiscible two-phase flow in porous media because it is simple, easy to get the desired contact angle and able to simulate immiscible phase flow with high-density ratio. Copyright q 2008 John Wiley & Sons, Ltd.