Synergistic Effect of MgO Nanoparticles and SDS Surfactant on Interfacial Tension Reduction for Enhanced Oil Recovery

Abstract Innovative methods to enhance oil recovery efficiency remain a high priority in the energy sector. This study investigates the potential of magnesium oxide (MgO) nanoparticles, both alone and with sodium dodecyl sulfate (SDS) surfactant, to improve oil recovery by reducing the interfacial tension (IFT) between oil and water. The research focuses on the physicochemical properties of MgO nanoparticles and their efficacy in IFT reduction, critical for Enhanced Oil Recovery (EOR). Preparation of MgO nanofluids was achieved using a Magnetic Stirrer and Sonics Vibracell VCX 750 Ultrasonic Homogenizer to ensure thorough mixing and dispersion. Characterization involved measuring density with Calibrated Density Bottles, dynamic and kinematic viscosity using a Falling Ball Viscometer, pH levels with an Electronic pH meter, and electric potential difference (mV). The Malvern Zetasizer Nano ZS assessed Zeta Potential (mV), Electric Conductivity (mS/cm), and Electrophoretic mobility (µmcm/Vs) for both the nanofluid and the surfactant-nanofluid systems. Paraffin oil served as the oil phase, with nanoparticle (NP) concentrations tested at 0.01, 0.03, 0.05, 0.1, and 0.5 wt%. The SDS concentration remained constant at 0.5 wt% throughout the study. We employed Pendant Drop Interfacial Tension measurements to evaluate the oil-water, oil-nanofluid, and oil-nanofluid + surfactant systems. Significant IFT reduction was observed—from 47.9 to 26.9 mN/m with a 0.1 wt% MgO nanofluid. Even a minimal concentration of 0.01 wt% MgO NP decreased notably from 47.9 to 41.8 mN/m. An IFT reduction of up to 70% was noted when MgO NPs were combined with SDS. This IFT reduction enhances oil mobility, suggesting the MgO-SDS system as an effective EOR technique. The study also recorded shifts in Zeta Potential from −2.54 to 3.45 mV and more alkaline pH levels from 8.4 to 10.8, indicating the nanofluid's altered surface charge and interaction dynamics. These physicochemical changes, aided by SDS, improved the dispersion and stability of MgO nanoparticles at the oil-water interface, thus boosting oil displacement efficiency. These findings highlight the potential of the MgO-SDS system as a cleaner alternative to traditional EOR methods that use toxic chemicals, offering economic benefits from enhanced reservoir performance. However, practical challenges remain, including ensuring nanoparticle stability and compatibility under diverse reservoir conditions, managing surfactant adsorption, and scaling up to field-level operations. Future research must address these issues while maintaining interdisciplinary collaboration and rigorous field studies. In conclusion, incorporating MgO nanoparticles and SDS surfactant presents a promising approach to improving oil recovery efficiency. Further investigation into its field application and economic feasibility is essential to gauge the potential of this technology in the energy industry.