INVESTIGATION OF METHODS TO MAKE ROCKS MORE WATER WET

Enhanced oil recovery (EOR) is an essential method to maximize the extraction of residual oil from reservoirs. EOR methods can be classified as gas flooding, hydrocarbon miscible injection, thermal and chemical injection. Wettability is one of the key parameters targeting the remaining oil-in-place. Few studies have focused on improving oil recovery in sandstone reservoirs by wettability alteration. The objective of this dissertation is to prove that altering the wettability of a sandstone rock to preferentially water-wet condition will reduce the remaining oil saturation and thus increase the percentage of recovered oil. One best commercial surfactant (AOS14-16) was after analysing the interfacial properties of two surfactants. Best surfactant then was tested for their ability to alter the wettability of sandstone rocks. The ability of selected surfactants to increase the percentage of recovered oil then was examined using oil-treated cores by water and gas injections. AOS significantly improve oil recovery from sandstone through spontaneous imbibition.