Numerical investigation of oil-water interfacial flow dynamics in porous media: Effects of anisotropic pore structures on the critical pressure difference

초록

In this study, we numerically investigate the effects of anisotropic pore structures on oil-water interfacial penetration using direct numerical simulations based on the level contour reconstruction method. Building on our previous two-dimensional study, which identified penetration as a local path-finding problem and proposed a Young-Laplace-based theoretical model for the critical pressure difference, we extend the analysis to both two-and three-dimensional systems with particular attention to the effects of anisotropic pore structures. Two-dimensional simulations reveal that pore anisotropy, characterized by aspect ratio and inclination angle, significantly influences the critical pressure difference by altering local interfacial curvature and surface tension forces. A correction function is introduced to account for these effects, enabling accurate prediction of the critical pressure difference. Three-dimensional simulations further demonstrate the multiple curvature effects associated with structural topology on the interfacial penetration, which cannot be represented by two-dimensional systems. The effective characteristic length scale is introduced with a new structural coefficient, leading to a combined simple semi-empirical model. The proposed model shows good agreement with simulation results across a wide range of anisotropy, characteristic length scales, and structural variations. A validation example using three-dimensional randomized anisotropic pore structures confirms that our semi-empirical model reasonably reproduces critical pressure differences in three-dimensional anisotropic porous media.

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