Suppressing Viscous Fingering in Porous Media with Wetting Gradient

The viscous fingering phenomenon often occurs when a low-viscosity fluid displaces a high-viscosity fluid in a homogeneous porous media, which is an undesirable displacement process in many engineering applications. The influence of wetting gradient on this process has been studied over a wide range of capillary numbers (7.5 x 10(-6) to 1.8 x 10(-4)), viscosity ratios (0.0025 to 0.04), and porosities (0.48 to 0.68), employing the lattice Boltzmann method. Our results demonstrate that the flow front stability can be improved by the gradual increase in wettability of the porous media. When the capillary number is less than 3.5 x 10(-5), the viscous fingering can be successfully suppressed and the transition from unstable to stable displacement can be achieved by the wetting gradient. Moreover, under the conditions of high viscosity ratio (M > 0.01) and large porosity (f > 0.58), wetting gradient improves the stability of the flow front more significantly.

Automated summary

The influence of wetting gradient on the viscous fingering phenomenon was studied using the lattice Boltzmann method. It was found that the gradual increase in wettability of the porous media improves the flow front stability and can suppress viscous fingering. The wetting gradient has a more significant effect on flow front stability under conditions of high viscosity ratio and large porosity.