Beyond the Lenormand phase diagram: Self-regulation mechanisms for controlling two-phase flows in porous media

Abstract

It is unclear why two-phase fluid flows in porous media develop a series of fluid displacement patterns. This study treats a two-phase flow system as an open thermodynamical system with a two-phase displacement process that follows the principle of the minimum operating power (MOPR). When different constraints are imposed on the system, the pore-scale interfacial dynamic response to this principle varies significantly, and a series of self-regulation mechanisms exist. These new findings not only explain the physical origins of the diverse fluid displacement patterns and interface reconstruction events but also provide new insights into the interface invasion protocol.