Experimental Study of Use of Ionic Liquids in Enhanced Oil Recovery

Abstract

Chemical flooding process has shown great potential in Enhanced Oil Recovery (EOR). Unfortunately, chemicals used have some disadvantages such as high cost, high toxicity and high adsorption tendency. In this study, we aim at using Ionic Liquids (ILs) as alternatives for traditional chemicals. Ionic liquids are salts having melting point below 100°C and they found as a liquid at room temperature. Nine Ammonium and Phosphonium based ILs were screened. The screening was based on their solubility in brines of different compositions, thermal stability and ability to reduce the aqueous-oleic phase’s Interfacial Tension (IFT). The screening process flagged Ammoeng 102 as the favored ionic liquid. More investigations of Ammoeng 102 solutions indicated a sharp exponential decrease of IFT values with increasing concentration. On contrary to surfactant solutions, Lower IFT values were obtained with increasing brine salinity indicating the ILs superiority in high salinity reservoirs. Two tertiary flooding experiments were conducted using 500 ppm Ammoeng 102 diluted in 10% and 20% (w/w) brine salinity to investigate its recovery efficiency. Lower salinity secondary brine flooding provided higher recovery. The opposite trend occurred in tertiary ionic solution flooding where recovery is higher for high salinity ionic solution indicating the effectiveness of ILs in recovering oil in high salinity, high temperature environment. In addition, the low cost and low toxicity are more advantages to promote the use of Ionic liquids in future EOR processes.