Insights Into Interfacial Dynamic and Displacement Patterns During Immiscible Two-Phase Porous Media Flow Under Controlled Viscosity and Wettability Conditions

Abstract

Multiphase flow in porous media is fundamental to various geological processes, including carbon capture, geothermal energy production, and enhanced oil recovery. However, the role of fluid properties and surface wettability in determining displacement patterns during flow remains not fully understood. This study addresses this gap by examining the effects of fluid viscosity and wettability on two-phase flow through porous media using a combination of microfluidic experiments and high-resolution numerical simulations. Our findings indicate that viscosity and wettability significantly influence the morphology of fluid displacement, with lower viscosity ratios leading to viscous finger-like invasion patterns, while higher viscosity ratios result in more compact displacement fronts. A significant increase in interface area generation is identified during the transition from compact displacement to viscous flow. This aligns with the energy balance analysis, which reveals that a greater portion of the injected fluid energy is expended on creating new interfaces. Wettability also plays a critical role in displacement patterns, especially under intermediate conditions, causing more interfacial dynamics than water-wet and oil-wet conditions. These insights advance our understanding of pore-scale mechanisms and contribute to more accurate multiphase flow models, ultimately informing applications in resource extraction and underground fluid management.