Role of salinity concomitant with asphaltene and resin on the interfacial tension of ionic liquid from imidazolium family

Abstract

Imidazolium-based ionic liquids have been considered environmentally friendly surfactants with display high performance in the interfacial tension (IFT) reduction. On the other hand, adjusting/tuning ions composition of the aqueous media (such as SO4−, Ca2+, and Mg2+) is an important feature in the smart water-enhanced oil recovery process. Since oil composition (particularly asphaltene and rein fractions) demonstrates the remarkable impact on the interfacial behavior of crude oil/aqueous solution, the synergetic effect between [C12mim][Cl] IL and active ions in the seawater on the IFT of various synthetic oils were evaluated. The structural properties of asphaltene and resin fraction of two crude oil with API gravity of 32.3 (oil A) and 27.5 (oil B) (through preparing six synthetic oils) and tuning ion composition (through preparing five aqueous media) at an ionic strength of seawater (IS = 0.8 M) on the performance of the IL were evaluated. The results showed a lower IFT value of synthetic oils prepared by oil A than those prepared by oil B in the presence of all studied electrolyte solutions, due to the presence of more polar heteroatoms in the structure of asphaltene and resin extracted from oil A, indicates the dominant effect of the nature of oil type on the [C12mim]Cl surface activity compared to the effect of ion type (composition of brine).