Mohamed Almobarak

Natural gas injection (i.e., recycling) is a commonly used for enhanced oil recovery method and is potentially cost-effective and efficient. However, natural gas injection, particularly methane, often has a high minimum miscibility pressure (MMP) which likely exceeds the fracture pressure of many otherwise viable reservoirs.

Surfactants are favorable chemical additives that are widely utilized in enhanced oil recovery (EOR) due to their inherent abilities such as wettability alteration and interfacial tension (IFT) reduction. However, most of the commercially available surfactants are expensive, hazardous to the environment, and can readily adsorb on the surface of the porous rocks.

Wettability alteration seems to be the main physicochemical process during low salinity water injection in carbonate formations. A pH increase due to calcite dissolution during low salinity water injection may affect oil–brine–rock interaction and thereby wettability. However, far too little attention has been paid to quantifying the impact of such an pH increase on acidic oil–carbonate adhesion.