Pore-Scale Characterization of CO2 Displacement Front Progress through Porous Media Using a Free Energy Model Based on Phase-Field Lattice Boltzmann Method

Pore scale simulation of CO2 front development micro-mechanism through a porous medium has been investigated by a free energy model based on phase-field Lattice Boltzmann Method. Visualization of fluids distribution in breakthrough time indicates a strong dependence of front pattern on viscous and capillary forces interaction. Therefore, the dominance of each force imposes a special pattern on the system. According to the percolation theory, the increasing capillary number reduces invading fluid saturation and, consequently, sweep efficiency because the viscous fingering regime will intensify. However, when the viscosity ratio of displacing fluid to displaced fluid is high, a more stable and uniform pattern is recorded, while in the opposite case, flow front growth is facilitated. Impressive results have also been obtained regarding the wetting conditions so that under a strong imbibition process, the upward trend of displacement efficiency and the more stable regimes will not be achieved due to capillary suction effects. Thus, according to experimental studies, the viscous fingering phenomenon will be proportional to capillary suction. Furthermore, it should be noted that new areas have also been introduced to predict the displacement regimes.