The Effect of Wettability Alteration and Interfacial Tension on Tertiary Oil Recovery by Chemical Method in Carbonate Reservoir

Almost half of the world’s known oil reserves are in carbonate rocks. Recovery from these reservoirs by waterflooding is low. Therefore, these reservoirs are good candidate for enhanced oil recovery (EOR) techniques. Surfactant flooding which is in subset of chemical enhanced oil recovery (CEOR), can increases the recovery of these reservoirs by reduction of interfacial tension (IFT) and alteration of wettability. The aim of this work is to investigate the effect wettability alteration and IFT reduction by new ionic liquids (ILs) for CEOR in carbonate rocks with an Iranian crude oil. The work started by screening four ILs based on their surface activity and wettability measurements. Then coreflooding performed to study the effect of selected IL on ultimate oil recovery. Based on the screening process, [C18 mim][Cl] was found to be the optimum IL. Coreflooding with the selected IL revealed 13% increase in oil recovery compared to flooding with brine.