Experimental Investigation of the Effect of Silica Nanoparticles on Interfacial Tension and Wettability during Low Salinity Water Flooding: A Micromodel Study

Objective: The present paper investigates the effect of nanoparticle concentrations on the interfacial tension and wettability during the low salinity water flooding (LSWF) at microscale. Method: A wide range of LSW concentrations were prepared and investigated for their ability to modulate the interfacial tension with crude oil. The impact of salinity on the fluid-rock interactions was studied through contact angle measurements on water-wet, intermediate-wet and oil-wet glass substrates. Nanofluid systems at a fixed concentration of 0.1wt% were prepared by mixing the hydrophilic silica NPs with a wide range of LSW concentrations. Likewise, the impact of silica nanoparticles on the IFT was investigated. Results: The fluids interactions results suggest that the lowest IFT value can be achieved at 5000ppm. Contact angle studies in all wettability systems indicated a negligible effect of water salinity on the wettability alteration. However, the presence of silica nanoparticles in low saline water significantly reduced the values of IFT and contact angle. Consequently, the wettability was altered to a more waterwet condition. Conclusions: Oil displacement experiments in both water-wet, intermediate-wet and oil-wet glass micromodels indicated that LSW-augmented functional silica nanoparticles can offer enormous potential for improving oil recovery. A synergistic effect of LSW and the adsorption of nanoparticles at the interfaces appears to explain the improved oil sweep efficiency.