Effect of Cationic Chain Length Part of Ionic Liquid based on the Imidazolium on the Spreading Coefficient of Crude Oil on Dolomitic Rock Surface in the Presence of Sulfate and Chloride Ions

Surfactant flooding is one of the most effective methods of the enhanced oil recovery (EOR) technique since it can reduce the interfacial tension (IFT) and wettability of the crude oil oil/rock/formation brine system. The aim of this study is to investigate the effect of ions (NaCl and Na2SO4) on the efficiency of two ionic liquids (ILs) namely 1-dodecyl-3-methyl imidazolium chloride ([C12mim][C])) and 1-octadecyl-3-methyl imidazolium chloride ([C18mim][Cl]) with different alkyl chain lengths on the IFT reduction and wettability alteration using works of adhesion and cohesion and spreading coefficient. Based on the critical micelle concentration (CMC) measurement, the efficiency of ILs at three different concentrations (C), C<CMC, C=CMC, and C=CMC, are investigated to evaluate the wettability alteration on the dolomitic carbonate rock surface and oil spreading coefficient. The results show that the performance of IL with longer chain length depends on the salt type, although the importance of surfactant concentration is dominant compared with salt type effect. To sum up, it seems that the IFT reduction can improve the performance of the solution for wettability alteration. The worth mentioning point is that the highest spreading coefficient is obtained for the IL with shorter chain length ([C12mim] [Cl]) in the presence of NaCl salt.