Research subject: Enhanced oil recovery (EOR) is one of the key methods to increase oil recovery from reservoirs, utilizing chemical, physical, or thermal techniques. Among chemical methods, ionic liquids (ILs) have attracted attention as potential alternatives to traditional materials such as surfactants and polymers due to their unique properties, including stability under harsh environmental conditions such as high temperature and salinity, and tunability for specific reservoir conditions.
Research approach: Ionic liquids can serve as surfactant substitutes in enhanced oil recovery processes, but they require proper synthesis and development. Higher environmental sustainability and reduced water consumption are advantages of these materials compared to traditional methods. However, research shows that their impact on EOR performance is relatively limited and requires further optimization, laboratory tests, and simulations. In this article, recent research on the application of ionic liquids in enhanced oil recovery operations is comprehensively reviewed, focusing on their characteristics, mechanisms, experimental results, challenges, and future prospects.
Main results: A review of recent studies shows that ionic liquids can significantly reduce the water/oil interfacial tension and alter the wettability of reservoir rock, both of which are key factors in improving oil transport. For example, the ionic liquid 1-decyl-3-methylimidazolium triflate has shown the ability to reduce interfacial tension significantly. Tests suggest that these materials can recover up to 30% more of the original oil in place.Many ionic liquids also show a strong affinity for asphaltenes and act as solvents and dispersants. This property helps prevent asphaltenes from settling and depositing in the wellbore and around its production zone, which can significantly improve oil flow and production. Ionic liquids can reduce the viscosity of crude oil, making it easier to flow through the reservoir and reducing pressure gradients. However, most studies have been conducted on sandstone reservoirs, and research in carbonate reservoirs is limited, highlighting the need for further investigations.