Experimental Investigation of Wettability Alteration in Reservoir Rock Using Silica, Alumina and Titania Nanoparticles

In recent years, several studies have been conducted regarding wettability alteration in petroleum reservoir rock using hydrophilic Silica (SiO2), Alumina (Al2O3) and Titania (TiO2) nanoparticles in order to improve waterflooding process that results in enhanced oil recovery (EOR). The studies have showed the significant role of these nanoparticles; however, their potential in wettability alteration and enhanced oil recovery as well as stability of them compared to each other have not been cleared yet; thus, an integrated comparison of them seems necessary. In this study, in addition to evaluating stability and price of these nanoparticles, their impacts on wettability alteration and EOR were investigated on oil-wet sandstone core samples. By injecting the nanofluids prepared from these nanoparticles, it could be expected to alter the rock wettability condition from oil-wet to water-wet due to their hydrophilic properties. For this purpose in this research, ten similar slices of the core samples were floated in ten different concentrations of the nanofluids; and their wettability alterations were determined by measuring the contact angles through sessile drop technique at different aging times. Then, brine and the nanofluids were injected to the three similar core samples to evaluate oil recovery caused by injection scenario. The results indicated that Titania, Silica and Alumina nanoparticles, respectively, had the most impacts on wettability alteration in the rock and their impacts incremented by increasing the nanoparticles concentration. After the injections of Titania, Silica and Alumina nanofluids with the optimum concentration at 0.1 wt%, the ultimate oil recovery is enhanced up to 18.27, 15.66 and 12.38 %, respectively, compared to the waterflooding. However, challenges of the use of these nanoparticles including the lack of stability and price of Alumina and Titania which are types of metal oxide-based nanoparticles were more than Silica.