Relative permeability measurement in carbonate rocks, the effects of conventional surfactants vs. Ionic liquid-based surfactants

Abstract

In the present study, the effect of two different kinds of surfactants namely conventional (Sodium dodecyl benzene sulfonate (SDBS)) and ionic liquid (IL)-based surfactants are investigated on the tertiary oil recovery using relative permeability concept. In this way, besides the Amott wettability index measurement, unsteady state core flooding tests are performed to not only find the effect of surfactant injection on tertiary oil recovery, but also to investigate their effects on relative permeability of carbonate rocks. In addition, for more reliable conclusions regarding the possible mechanisms, interfacial tension (IFT), compatibility and emulsification tests are carried out as a function of concentration. According to the results obtained through the core flooding experiments, it can be concluded that the injection of SDBS which substantially reduces the IFT value leads to higher tertiary oil recovery (26% based on original oil in place (OOIP)) although the ILs revealed more compatibility at the presence of harsh salinity conditions at any examined IL concentration in this study. Finally, the results obtained by plotting the relative permeability data and mining into the cross points one can conclude that in the case of using ILs, the active mechanisms during the tertiary oil recovery is dominantly related to wettability alteration mechanism while in the case of SDBS, the IFT reduction is the active mechanism.