Synergy between TiO2 nanoparticles, surfactants and polymer in contact with resinous and asphaltenic synthetic oils for surface properties treatments

In this investigation, we examined the effects of various chemicals, including nanoparticles (NPs), Xanthan gum as a polymer, and two surfactants: sodium dodecyl benzene sulfonate (SDBS) and sodium bis-(2-ethylhexyl) sulfosuccinate (AOT), on the reduction of interfacial tension (IFT) and the alteration of wettability on carbonate rock surfaces. The first step of the investigation focused on the effects of the two surfactants on IFT reduction using distilled water (DW). In the second stage, we considered the impact of Persian Gulf water, a readily available water source for preparing aqueous solutions, on IFT reduction. The measurements indicated that the two surfactants could reduce the IFT to minimum values of 0.66 mN/m and 0.32 mN/m for 2000 ppm SDBS in DW with asphaltenic and resinous synthetic oil, respectively. However, solutions prepared with Persian Gulf water plus AOT at a concentration of 2000 ppm achieved minimum values of 0.63 mN/m and 0.43 mN/m for asphaltenic and resinous oil, respectively, demonstrating AOT's superior efficiency over SDBS in the presence of salinity. In the next stage, we examined the impact of different solutions on wettability alteration, which showed that it is possible to achieve a water-wet rock surface using 2000 ppm of AOT and SDBS. The results indicated greater efficiency of these surfactants for wettability alteration in the presence of resinous synthetic oil, which acts as a natural surfactant and enhances the wettability alteration of the rock surface. Additionally, IFT measurements indicated that NPs had no specific impact on IFT reduction; however, their presence could reduce contact angles to 20.1° and 23.2° for AOT and SDBS with resinous synthetic oil, respectively. This suggests a synergy between the NPs and the surfactants, particularly in the presence of both resinous and asphaltenic oil, with better results observed for resinous synthetic oil. In the final stage, we assessed the effect of the optimal chemical formulation, both in the absence and presence of Xanthan gum at a concentration of 300 ppm, with a slug size of 0.05 PV in different injection patterns. The results demonstrated the effectiveness of polymer preflush and soaking on the tertiary oil recovery with values of 9.7% and 13.6% based on the original oil in place (OOIP), indicating the significance of injection pattern and soaking.