Ionic liquids as a potential additive for reducing surfactant adsorption onto crushed Berea sandstone

Abstract

In chemical Enhanced Oil Recovery (EOR) applications, chemical sensitivity has been taken into account as a major challenge due to its interactions under harsh environment of the reservoirs leading to reduced oil recovery efficiency. For instance, surfactant adsorption onto the reservoir rock during chemical flooding processes causes chemical loss and hence degrades its performance in porous media. The addition of chemical which has been known as an environmental benign material could be applied to overcome surfactant adsorption. In this study, static adsorption experiments were conducted for two types of surfactant and three ionic liquid (IL)-based solutions using crushed Berea sandstone. Besides investigating their individual adsorption, the ability of imidazolium-based ILs and deep eutectic solvent (DES) which has been known as a biodegradable IL-based material with good solubility, to reduce surfactant adsorption was evaluated. Results indicate that surfactant adsorption is dependent on the surfactants types and concentrations. It was also indicated that ILs producing specific interactions with rock surface have a comparable possibility to adsorb onto reservoir rock, hence the potential to substitute surfactant as the adsorbate. The presence of certain concentration of IL in surfactant solution was found to be able to decrease surfactant adsorption onto crushed core sample. The addition of imidazolium-based IL and DES was able to decrease the anionic surfactant adsorption by three times. Other finding shows that DES also gives a significant reduction of in-house surfactant adsorption down to the noticeable value compared to other ILs. The different results on adsorption behavior obtained from the combination of various surfactants and ILs impart the high influence of the type of surfactant and IL applied.