New Insights Into Complex Interactions Between Heterogeneity and Wettability Influencing Two-Phase Flow in Porous Media

Coupled effects of wettability and pore geometry on pore-scale dynamics of immiscible two-phase fluid displacement were investigated using a multiphase lattice Boltzmann model in homogeneous and heterogeneous porous media under a wide range of contact angle theta(25 degrees <=theta <= 175 degrees). The observed invasion patterns indicate that the complex interactions between wettability and pore morphology play crucial roles in controlling the displacement patterns. The detailed pore-scale analysis enabled us to delineate how wettability influences the recovery efficiency of the defending fluid in homogeneous and heterogeneous porous media. As the wetting condition changes from strong drainage to imbibition, we observed a transition from burst to corner flow leading to a compact displacement and hence a higher recovery efficiency in the heterogeneous sample. The present study sheds new insights on how the interaction between wettability and heterogeneity influences fluid displacement in porous media.