Pore-Scale Numerical Simulation of CO2–Oil Two-Phase Flow: A Multiple-Parameter Analysis Based on Phase-Field Method

A deep understanding of the pore-scale fluid flow mechanism during CO2 flooding process is essential to enhanced oil recovery (EOR) and subsurface sequestration. Two-phase simulations were performed simulate based on phase-field method in this study. Two-dimensional models with random positions sizes grains circular shape constructed reproduce topology porous media heterogeneous pore size distributions reservoir rock. multiple-parameter analysis was investigate effects capillary number, viscosity ratio, wettability, density, gravity, interfacial tension, absolute permeability two-phase characteristics. The results indicated that when number ratio large enough, i.e., log Ca = −3.62 M −1.00, fingering phenomenon not obvious, which could be regarded as a stable displacement process. saturation increased increase PV value injected CO2. Once broke through at outlet, efficiency approached stability. Two types broken behaviors fluids observed wettability alternation, snap-off viscous breakup. Snap-off occurred forces dominated process, while breakup low ratio. With mainly controlled by force gravity. decrease tension between media, displaced phase effectively. In mixed-wet model, percentage nonoil-wetted grains, intersecting point relative curve moved right led higher recovery.