The application of network modelling techniques to multiphase flow in porous media

A review of the utility of network models is presented to describe multiphase flow at the pore-scale. Precise details of each set of simulations can be found in the appropriate reference and only the most pertinent results are presented here. The main aim of this paper is to highlight the effectiveness of network models as interpolative and interpretative numerical tools. Both primary and secondary capillary-dominated, two-phase displacements are considered and well-documented hysteresis effects are successfully reproduced. Waterfloods of mixed-wet media are subsequently described and associated variations in relative permeability and recovery efficiency reported. Optimum recovery is obtained from networks containing a 50-50 mix of oil-wet and water-wet pores. Finally, a discussion of unsteady-state drainage and imbibition models follows and these are applied to waterfloods in finely-laminated porous media. Results highlight the complex interactions between capillary forces, viscous forces and geological structure.