Multiphase flows in porous media are important in many natural and industrial processes, including geologic C02 storage, hydrogen geostorage, enhanced oil recovery, and water infiltration into soil. A macroscopic description of these processes requires a fundamental understanding of the pore-scale mechanisms of fluid-fluid displacement. The combined effects of wetting, capillarity and viscous forces at the pore scale lead to complex behavior, including the formation of thin films and pinch-off and reconnection of the fluid-fluid interface. Despite many experimental and modeling studies of pore-scale two-phase flow, interface morphology and dynamics over the complete range of wetting conditions are yet to be fully understood, especially in the regime where the invading fluid is strongly wetting to the solid surface.
