A lattice Boltzmann study on the effect of fluid viscosity contrast on the retention behavior of two‐fluid flow in porous media

Abstract

AbstractIn this contribution, the Shan‐Chen (SC) two‐phase flow model of the lattice Boltzmann method (LBM) is numerically implemented to simulate multiphase fluid flow on microtomography (µ‐CT) data of a sphere packing. From the model, the saturation degrees of the fluid phases, i.e. invading and displaced fluids, are extracted from the computed lattice density distribution functions. Several simulations are run with different degrees of kinetic viscosity contrast between the fluid phases within increasing increments of capillary pressure. At each increment, the relative permeability regarding each fluid phase is computed as a function of the saturation degree. The motivation of this study is to (1) investigate the effect of the kinetic viscosity contrast between the fluid phases on the retention behavior, (2) analyze the range of validity of the van Genuchten relation according to the computed retention data and (3) propose an extension towards an upscaling micro‐to‐macroscopic hierarchic scheme for the simulation of multiphasic fluid flow in unsaturated porous media.