Efficiency of ionic liquids for chemical enhanced oil recovery

Abstract

Substantial amount of crude oil remains in the reservoir after primary and secondary production. Chemical flooding is one of the enhanced oil recovery (EOR) methods; however, chemicals (i.e., Surfactant) used are sensitive to the harsh environment characterizing the local reservoirs. The current study aimed at investigating the utilization of ionic liquids (ILs), known as environment friendly salt with good solubility, thermal stability and effective surface activity, as an alternative to conventional organic surfactants in enhanced oil recovery process. In this work, screening tests of nine ILs were performed. These ILs were diluted in different brine solutions of different salt compositions at 10 % (w/w) salinity and their solubility, thermal stability and surface activity in presence of Saudi medium crude oil were tested. Tetra alkyl ammonium sulfate known as Ammoeng 102 was found to be the ionic liquid of choice. Further investigations on Ammoeng 102 solutions at 10 and 20 % (w/w) salinity were conducted and IFT measurements indicate enhanced surface activity of Ammoeng 102 with increasing solution salinity. Effects of pressure and temperature on interfacial tension (IFT) were also tested and the results indicate minor effects. Adsorption test indicates high Ammoeng 102 adsorption tendency with more adsorption for higher salinity solution. Different flooding scenarios were conducted in sandstone rock samples to investigate the effectiveness of Ammoeng 102 IL as an EOR chemical. The findings indicate promising results for ionic solution flooding in secondary mode at irreducible water saturation (S wirr ). Ultimate recovery obtained is higher than that obtained with combined secondary brine flooding followed by tertiary ionic solution flooding at residual oil saturation (S or ). Injection of slug of ionic solution in secondary mode provides lower recovery compared to that recovered with continuous ionic solution injection in the same mode. Rock water content affects recovery efficiency indicating higher oil recovery for secondary brine and tertiary ionic solution flooding at low S wirr . Contact angle and relative permeability measurements demonstrate the role of wettability alteration behind the extra oil recovery which is very much affected by ionic liquid concentration that can be altered by dilution with formation and injected brines.

Experimental Study of Enhanced-Heavy-Oil Recovery in Berea Sandstone Cores by Use of Nanofluids Applications

“…5, and the particles that have high SSA providing an excess pressure in the wedge/film. Buckley and Fan (2005) suggested that the hydrophilic silica nanofluids can give a high performance on oil recovery because of wettability alteration and the reduction on the IFT. The IFT influences capillary pressure, capillary number, and adhesion tension.…”

Enhanced heavy oil recovery using 1‐Ethyl‐3‐Methyl‐Imidazolium Acetate

“…Bin‐Dahbag et al also mention that increasing the concentration of an IL (Ammoeng 102) resulted in decreasing the contact angle of the oil droplet, and caused a change in rock wettability from marginally oil‐wet to medium water‐wet conditions. Wettability alteration might therefore be the third possible mechanism contributing to the efficiency of [EMIM][Ac] in the recovery of oil, as observed by Bin‐Dahbag et al In summary, three possible mechanisms seem to be significant in improving the RF of oil using ILs, namely: electrostatic interactions, aromatic interactions, and viscous forces. As for the third mechanism, ILs with high viscosity cause an increase in the viscosity of the aqueous phase, leading to a decrease in mobility ratio between the aqueous and oil phases.…”

Investigation of Different Ionic Liquids in Improving Oil Recovery Factor

“…Limited studies have been carried out to demonstrate the effects of wettability alteration by ionic liquids. Bin-Dahbag et al (2014) have done a series of flooding experiments on Berea sandstone samples by using different ionic liquids concentrations to investigate the wettability alteration [12]. It was concluded that ILs have the ability to shift the rock wettability from oil wet towards water wet as a result of the interaction between oil, rock, and IL [12].…”

“…Bin-Dahbag et al (2014) have done a series of flooding experiments on Berea sandstone samples by using different ionic liquids concentrations to investigate the wettability alteration [12]. It was concluded that ILs have the ability to shift the rock wettability from oil wet towards water wet as a result of the interaction between oil, rock, and IL [12]. A similar study was conducted by Mohammed and Babadagli (2016) to investigate the effect of several imidazolium ionic liquids to modify the wettability of oil-wet limestone and sandstone.…”