Study of Ionic Liquids as Effective Solvents for Enhanced Heavy Oil Recovery

Abstract

Injecting chemicals in reservoirs is an efficient technique to improve oil recovery. In this study, several types of Ionic Liquids (ILs) were initially screened using the Conductorlike Screening Model for Realistic Solvents (COSMO-RS) model. COSMO-RS, in particular, is capable of providing predictions of the thermodynamics properties of ILs. A comprehensive screening study of 148 probable cations and 46 anions was performed in order to shed some light on the interaction of ILs with hydrocarbons via the calculation of the capacity of the screened ILs to hydrocarbons fractions and water. The most suitable ILs for our purposes were chosen, and employed for improving heavy oil (14o API) recovery from sand pack at room conditions taking the cost, physical and chemical properties of the ILs into consideration. The selected ILs were 1-Dodecyl-3- methylimidazolium chloride [DMIM][Cl], 1-Ethyl-3-methylimidazolium acetate [EMIM][Ac], 1-Ethyl-3-methylimidazolium methyl sulfate [EMIM][MS], 1-Hexyl-3- methylimidazolium tetrafluoroborate [HMIM][Bf4], 1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM][Tf2N], 1-Methyl-3-octylimidazolium tetrafluoroborate [MOIM][Bf4], 1-Methyl-3-octylimidazolium hexafluorophosphate [MOIM][PF6], 1,3-Dimethylimidazolium tosylate [dMIM][TOS], 1-Benzyl-3- methylimidazolium tosylate [BenzMIM][TOS], N-methylpyridinium tosylate [MPyr][TOS], 1-Ethyl-3-methylimidazolium chloride [EMIM][Cl], 1-Benzyl-3- methylimidazolium chloride [BenzMIM][Cl], and Trihexyltetradecylphosphonium chloride [THTDPh][Cl].