Sharif Digital Repository

The modification of the surface wetting characteristics in fractured oil-wet carbonate reservoirs, by reversing wettability from oil-wet to water-wet, leads to improved oil recovery. However, in order to obtain a successful oil recovery process, it is crucial to understand the active mechanisms of wettability alteration. This study looks at the effect of sulfate ions as one of the most promising wettability influencing ions on the wetting properties of oil-wet calcite; the effect is studied both with and without the presence of cationic surfactant and possible mechanisms of wettability alteration are explored. A number of analytical techniques were utilized to analyze the mineral surface... 

Over 60% of the world's discovered oil reserves are held in carbonate reservoirs, which are mostly naturally fractured. Conventional water flooding results in low oil recovery efficiency in these reservoirs as most of them are oil-wet. On account of negative capillary forces, injected brine cannot penetrate simply into an oil-wet matrix of fractured formations to force the oil out. Wettability alteration of the rock surface to preferentially more water-wet state has been extensively studied using both smart water and surfactants separately. This study aims to study the effects of Mg2+ as one of the most important wettability influencing ions on the wetting properties of oil-wet carbonate...