| Enhanced oil recovery (EOR) from naturally fractured reservoirs (NFR’s) involves the injection of external agents into the fracture networks to extract the resident crude oil in the matrix. Characteristically, these agents displace the oil by diffusion (if miscible) or spontaneous imbibition (if immiscible). The present work performs two-dimensional simulations of these processes at the pore-scale and extends the results to core-scale by using the Lattice Boltzmann method (LBM). Simulations of miscible recovery of kerosene and light mineral oil by injection of pentane are performed to observe the displacement profiles. The LBM model is then extended to simulate the co-current and counter-current spontaneous imbibition of water in a kerosene saturated water-wet sand pack. The oil-water interface development is analyzed at the pore-scale, and the saturation profiles are compared with experiments from literature. Two-phase relative permeabilities of the displacement processes are determined, and their dependence on various physical parameters is studied. |
