Pore Network Modeling and Simulation for Studying the Effect of Heterogeneities on Miscible Displacement

Pore network modeling and simulation is used to study miscible displacement in heterogeneous porous media under unsteady state conditions. The goal of this paper is to investigate the effect of pore space morphology and mobility ratio on miscible displacement processes. A two dimensional (2-D) pore network of interconnected pores with distributed effective radii is used as a model of the pore space. In this model first the flow field is solved and then the concentration distribution is determined using the convective-diffusion equation (CDE) for each pore in the network. We have considered the presence of a steady state flow of first contact miscible solvent to the network. The results show the effect of heterogeneity of the network, pore size distribution (PSD) and mobility ratio on viscous fingering formation, breakthrough time, recovery factor (RF) and longitudinal dispersion. The results of Monte Carlo simulation show that by increasing the heterogeneity of the network the fingering formation, breakthrough time and longitudinal dispersion will increase while the RF decreases. According to the results, the longitudinal dispersion depends on the network size and will increase gradually with is increase. Also the increase of the mobility ratio will decrease the break through time and increase fingering formation.