Oil and gas are still primary energy source in the world, despite the advancements in renewable energy. Enhanced Oil Recovery (EOR) has an important task for increasing oil recovery, especially for heavy oil reservoirs. Many researchers showed chemical enhanced oil recovery, particularly surfactant is most efficient method in many reservoirs. But most of these projects were not commercially successful due to high cost and environmental issues. Ionic liquids (ILs) gained more attention as an alternative to surfactants. But synthesis and purification processes makes them expensive for industrial application and some types of them are toxic and not biodegradable. Recently, another form of ILs, namely Deep Eutectic Solvents (DESs) were discovered as cheaper and greener alternative to conventional ILs.