Study on interfacial properties of Imidazolium ionic liquids as surfactant and their application in enhanced oil recovery

Abstract

Enhanced oil recovery is a tertiary method for recovering oil trapped in porous rock of the reservoir. This oil becomes trapped in porous media because of capillary forces. The reduction of these forces by surfactants is an important aspect of enhanced oil recovery. The development of ionic liquid−based surfactants has gained significant interest in their use as cationic surfactants in analytical methods and separations. In the current study, functionality of long chain imidazolium ionic liquids as surfactants have been investigated by measuring, dynamic interfacial tension of water/oil system and their ability to reduce IFT under harsh conditions of salinity and temperature. In the present study, an advantage of 1-hexadecyl-3-methyl imidazolium bromide (C16mimBr) over traditional cationic surfactant (CTAB) has been highlighted. The efficiency of both (C16mimBr & CTAB) in recovering additional oil when used in an EOR process has been found out by conducting lab-scale core flooding experiments. Also, small Poly (dimethylsiloxane), (PDMS) microchannels have been prepared and moduled as oil filled porous structures in the reservoir. Microscopic images of surfactant solutions flowing through these channels have been recorded to find out whether they form emulsions while flowing. The experiments revealed that C16mimBr is more efficient in reducing interfacial tension between water/oil system and thus recovering more entrapped oil than traditional cationic surfactant CTAB. The results obtained here reflect high interfacial activity, high oil solubility due to the formation of emulsions and stability under harsh reservoir conditions for the IL in consideration.