Deep Eutectic Solvents: Comprehensive Review and Future Directions on Synthesis and Oilfield Applications

Deep eutectic solvents (DESs) are widely used across scientific fields, including the oil industry. DESs, synthesized by combining specific hydrogen bond acceptors and donors, offer customizable properties. DESs are used in various industrial processes like pharmaceutical synthesis, biocatalyst development, nanomaterial manufacturing, molecule desulfurization, and gas capture. DESs are stable under harsh conditions, customizable, and low toxicity, making them ideal for many oilfield applications. This study focuses on their use in enhanced oil recovery and drilling engineering while addressing associated challenges and proposing solutions. DESs can alter wettability and act as substitutes for surfactants, especially in shale inhibition and mud loss control. They are cost-effective and environmentally friendly alternatives to toxic chemicals in the upstream oil sector, with tunable features. However, DESs have limitations such as high viscosity, turbidity, and challenges in achieving phase separation during liquid-liquid extraction. The use of DESs in industrial processes raises challenges related to price and sustainability. Practical use of DESs requires extensive laboratory-scale experimental research for effectiveness and safety. This review analyses the latest research on using these chemicals in the petroleum sector, specifically upstream oil operations.