Micro-hydrodynamics of immiscible displacement inside two-dimensional porous media

In this paper, a Boolean lattice-gas model based on field mediators proposed by Santos and Philippi (Phys Rev E 65:046305, 2002) is used for the simulation of fluid–fluid interface displacement inside two-dimensional simplified porous media. A new procedure is introduced to allow the simulation of different viscosity ratios on the framework of lattice-gas models. The model is verified by simulating the spreading of a liquid drop on a solid surface and by comparing the simulation results with experimental spreading data. Some important basic physical mechanisms occurring at the pore scale are simulated and compared qualitatively with experimental visualizations. The break-off phenomenon of the fluid–fluid interface is observed in bifurcations, when a wetting (or non-wetting) fluid is displacing a non-wetting (or wetting) fluid. The role of break-off is shown to be different in imbibition and drainage processes in agreement with experimental results. Finally, the influence of wettability on the displacement efficiency is investigated in two-dimensional random arrays of disks.