On the Effect of Silica Nanoparticles on Wettability Alteration during Water Flooding to Heavy Oils - A Micromodel Study

Abstract

Here, a series of injection experiments were performed on five-spot glass micromodel which was initially saturated with the heavy oil. Distilled water and dispersed silica nanoparticles in water (DSNW) at different values of weight percent were used as injected fluids. The macroscopic efficiency as well as fluid distribution in the pores/throats was monitored from analysis of continuously provided pictures during the experiments. Contact angles of the glass surfaces at different conditions of wettability were measured using sessile drop method. The results disclosed that the silica nanoparticles caused enhancement of sweep efficiency during water flooding; ultimate efficiency for DSNW (0.1%w) flooding increased by a factor of 8.7% in comparison to distilled water flooding. This increment in oil recovery was reached to 26% by increasing silica nanoparticles weight percent from 0.1%w to optimum concentration of 3%w. The distribution of DSNW solution during flooding tests in pores/throats showed strong water-wet state after flooding with high concentration of nanosolution. The results of sessile drop experiments showed that coating of the medium surface with high concentration of DSNW could make a strongly water-wet surface. Moreover, due to adsorption of silica nanoparticles on the glass surface in pores/throats, a reduction in absolute permeability was observed.