Ionic optimization of engineered water for enhanced oil recovery in carbonate reservoirs: A case study

As oil reservoir pressure diminishes with production, technology for efficient oil recovery becomes imperative. Water flooding emerges as a proven method to restore reservoir pressure, emphasizing the critical role of water composition. This study explores the ionic impact of engineered water on oil recovery in carbonate reservoirs. Through contact angle, interfacial tension, and core flooding experiments, seawater with double sulfate ion concentration (SW2S) performs best, altering wettability and reducing IFT via sulfate-driven ionic interactions. SW2S caused the IFT to change by -5.63, altered the contact angle by 65.72, and increased oil recovery with the added benefit of promoting emulsion formation, particularly in the S-1 crude oil system, where it achieved the oil recovery by 10.27%. Results reveal the influence of crude oil components on water composition effectiveness, with resin and asphaltene playing key roles. The study emphasizes considering crude oil characteristics when selecting optimal water compositions, proposing a combination of sulfate, magnesium, and calcium ions to enhance oil recovery in carbonate reservoirs. This research provides crucial insights into the ionic effects of engineered water, emphasizing the significance of reservoir and crude oil specifics in water composition optimization.