Investigation into the Effect of Water Fraction on the Single-Phase Flow of Water-in-Oil Emulsion in a Porous Medium Using CFD

Effect of water fraction on the flow characteristics of water-in-oil (W/O) emulsions through porous medium has been investigated by experiments and computational fluid dynamics (CFD). Flooding experiments of W/O emulsions (E₁, E₂, E₃: water fraction, θ_w (%v/v), = 11.8, 22, to 38%, respectively) and those of original oil (E₀, θ_w = 0) were performed using a packed glass bead porous medium. The experimental information was used in building and validating a single-phase pore-scale flow model using the COMSOL Multiphysics 5.4 Software (base model). The simulated porosity (φ = 0.27) and absolute permeability (K_a = 74 mD) of the base model are in good agreement with those from the experiments (porosity φ = 0.30 and absolute permeability K_a = 68 mD). The simulated pressure drop and effective viscosity also compared fairly well with those obtained from the experiments (R² = 0.98; and 0.83, respectively). Ultimately, the CFD results show that the water fraction of W/O emulsion increased the viscosity, which subsequently increased the pressure drop. In addition, it was confirmed that the injection velocity and the pore size affect the flow characteristics in the porous medium.