فهرست نشریات علمی دسترسی آزاد ایران

Experimental analysis and numerical simulation of CO₂ injection in oil and gas reservoirs are essential for CO₂ sequestration and enhanced oil recovery applications. However, experimental approaches are often expensive and time-consuming, while numerical methods require input parameters such as two-phase relative permeabilities. In this study, two-phase flow simulations are conducted using a numerical solver based on the phase-field approach under steady-state conditions to determine relative permeability curves. Specifically, flow simulations are performed in realistic porous media, and nonconstant fluid viscosity and density are incorporated, addressing limitations of previous studies. Therefore, the main contribution of this work is the determination of CO₂–oil relative permeabilities in realistic porous media extracted from micro-CT images under conditions of variable fluid viscosity and density. In addition, the influences of wetting properties and hysteresis on relative permeability behavior are investigated.The numerical results indicate that increased wettability toward the injected fluid enhances displacement efficiency by shifting the intersection point of the relative permeability curves to the right, leading to higher oil recovery, particularly at larger contact angles corresponding to non-wetting conditions and at lower surface tensions. Furthermore, the separation between imbibition and drainage relative permeability curves, representing hysteresis effects, becomes more pronounced as wettability shifts toward larger contact angles. These findings demonstrate the capability of steady-state pore-scale simulations based on the phase-field approach to reliably determine CO₂–oil relative permeability curves when realistic porous media and nonconstant fluid properties are considered.