Unveiling the Synergistic Effect of ZnO Nanoparticles and Surfactant Colloids for Enhanced Oil Recovery

Abstract Although chemical flooding is widely used to enhance oil productivity at lower cost, the continuously increasing prices of chemicals is a real barrier to achieve such an aim. Hence, various ways have been explored to reduce the amount of chemicals used while yielding the same performance or even higher to make the whole process cost efficient. Herein, we investigate the use of zinc oxide nanoparticles (ZnO NPs) to improve the surfactant-based extraction of an organic fluid (n- dodecane) from a porous medium (sandstone). The main mechanism is a synergetic effect between surfactant and nanoparticles in reducing the oil/water interfacial tension (IFT), which assists in overcoming the capillary trapping of oil. In addition, the aqueous solutions of the investigated surfactant (sodium dodecyl sulphate) provide better suspension stability for ZnO nanoparticles compared to water. The presented experiments showed an increase in oil recovery efficiency of 8% when both ZnO and surfactant are used compared to the surfactant-based oil recovery processes. To further explain the dominant mechanism for the increased oil production, simulation models were constructed and showed wettability shift to more water wet characteristics.