A Computational Study of the Efficiency of Using Low-Concentration Nanoemulsions with Diesel Fuel to Enhance Oil Recovery

The article presents the results of systematic numerical studies on the efficacy of low-concentration nanoemulsions for enhanced oil recovery. A series of computational investigations was conducted to examine the displacement regimes of oil from digital core models with varying permeability using the developed low-concentration diesel fuel-based nanoemulsions. The volume fraction of diesel fuel in the emulsions was 1 vol.%. The volume fraction of the emulsifier ranged from 0.05% to 0.4%. The nanoemulsions demonstrated high efficiency across the entire range of permeabilities considered. It was shown that the behavior of the displacement front for water and for emulsions differs fundamentally. The waterflood front for emulsions is significantly more uniform and exhibits more complete cross-sectional saturation of pore channels compared to water flooding. With an increase in the capillary number, the oil displacement coefficient achieved by nanoemulsions increases. However, the maximum incremental effect from the use of nanoemulsions is observed at the minimum values of the capillary number. This finding indicates that the primary mechanisms underlying the positive impact of emulsions on oil displacement are the reduction in interfacial tension and the improvement of wettability.