Research of CO2-Soluble Surfactants for Enhanced Oil Recovery: Review and Outlook

Abstract

CO₂ foam injection has been shown to be effective under reservoir conditions for enhanced oil recovery. However, its application requires a certain stability and surfactant absorbability on rock surface, and it is also associated with borehole corrosion in the presence of water. Adding surfactants to CO₂ can enhance the interaction between CO₂ and crude oil and control the CO₂ mobility, thereby improving the performance of CO₂ flooding. This paper presents a review of the research of CO₂-soluble surfactants and their applications. Molecular dynamics simulation is introduced as a tool for analyzing the behavior of the surfactants in supercritical CO₂ (scCO₂). The applications of CO₂-soluble surfactants, including CO₂ thickening, reducing miscibility pressure, and generating supercritical CO₂ foam, are discussed in detail. Moreover, some opportunities for the research and development of CO₂-soluble surfactants are proposed.