Abstract
In this work, the synergistic effects of SmartWater in polymer flooding, surfactant-polymer flooding, carbonated waterflooding, and foam assisted gas injection processes were explored. A suite of multiscale experimental data was analyzed to demonstrate and quantify the benefits of water chemistry synergies in these different enhanced oil recovery (EOR) methods. The multiscale experimental data analyzed comprised of polymer rheology, core floods, foam stability and rheology, besides evaluating the zeta potential results obtained from surface complexation modeling (SCM).
SmartWater increased the oil recoveries by 5-7% in addition to reducing the polymer concentration requirements by one-third in polymer flooding. Synergizing SmartWater with surfactant-polymer flooding increased the oil recovery by 4% besides lowering the polymer and surfactant consumption by 50%. SmartWater has been found to synergistically combine with carbonated waterflooding to increase the CO2 dissolved volumes by 25-30% for effectively lowering the pH at both calcite/brine and crude oil/brine interfaces. The availability of more CO2 dissolved volumes in SmartWater can cause enhanced oil swelling, greater oil viscosity reduction, and increased wettability alteration through pH induced modification of surface charges for higher oil recovery. SmartWater increased the foam stabilities by 2-3 times, foam apparent viscosities by 1.5 times, and porous media foam pressure drops by 50% to ensure the propagation of more stable and viscous foams deeper into the reservoir for better mobility control.
The findings of this study have a practical impact on how the industry can efficiently operate EOR projects. SmartWater-based synergistic technologies can reduce the costs due to lowered volume requirements of different EOR agents and they can also increase oil recoveries to result in more practical, efficient, and economical EOR projects in the field.
