Simulation of fluid percolation in a rough-walled rock fracture

A comparison of experimental and numerical results is presented addressing two-phase immiscible displacement in rough fractures. Quasi-static, capillary displacement in a rough fracture is modeled using the modified invasion percolation approach proposed by Glass et al (1998), and the results are compared against experimental observations obtained from two-phase flow through a rock fracture using x-ray computed-tomography scanning. The model is based on an algorithm seeking the least resistant pathway for the advancement of the invading fluid using the Young-Laplace equation and accounting for local in-plane curvature of the advancing fluid front. The saturation distribution map generated by the model yields good agreement with the experimental phase distribution and presents more realistic phase structures than those obtained from the conventional invasion percolation approach. The improvement in the results obtained with the modified invasion percolation approach is attributed to the contribution of the in-plane curvature term, which captures the effect of regionalized apertures, rather than single-point apertures, on the shape of the invading front. Glass RJ, Nicholl MJ, Yarrington L (1998) A modified invasion percolation model for low-capillary number immiscible displacements in horizontal rough-walled fractures: influence of local in-plane curvature. Water Resour Res 34:3215–3234