Monitoring the influence of dispersed nano-particles on oil–water relative permeability hysteresis

• The influence of dispersed silica particles on hysteretic trend of two-phase curves of oil–water relative permeability.
• Finding the dominant mechanism of EOR during nanofluid injection processes.
• Experimental unsteady state displacement tests of water/water saturated by dispersed nanoparticles-light crude oil systems.

In recent years, polysilicon nanoparticles are used to enhance the oil recovery through the water injection process in oilfields. The contributing mechanisms are the reduction of interfacial tension and wettability alteration which lead to improving or decreasing the oil phase relative permeability and can be traced by change of relative permeability curves. However, profound understanding of the effect of dispersed nano-silica particles on the hysteretic behavior of relative permeability curves remains a controversy topic in the literature.The current study illustrates the influence of dispersed silica particles on hysteretic trend of two-phase curves of oil–water relative permeability. Displacement tests of light crude oil by water as well as water dispersed Nano-silica particles were performed on a sandstone rock sample, and the relative permeability curves of oil and water phases were considered for two successive cycles of imbibition and drainage processes. Primarily, the results revealed that the degree of hysteresis in two phase relative permeability decreased as the dispersed nano-silica particles were used in the tests; besides the hysteretic behavior of relative permeability curves decreased as the injection proceeded into its second cycle. Moreover, the relative permeability of non-wetting phase changed significantly while the changes for wetting phase did not appear quite considerable. The results of this work can help with finding an appropriate relative permeability curves during EOR processes in case of changing the direction of displacement.