A comprehensive review on CO2 thickeners for CO2 mobility control in enhanced oil recovery: Recent advances and future outlook

• Published in: Journal of industrial and engineering chemistry (Seoul, Korea) Vol. 126; pp. 69 - 91
• Main Authors: Ricky, Emanuel X., Mwakipunda, Grant Charles, Nyakilla, Edwin E., Kasimu, Naswibu A., Wang, Chao, Xu, Xingguang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 25.10.2023; 한국공업화학회
• Subjects: CO2 flooding; CO2 mobility; CO2 thickener; Enhanced oil recovery; Polymer; Surfactant; 화학공학; Polymer; CO2 thickener; CO2 flooding; Enhanced oil recovery; Surfactant; CO2 mobility
• ISSN: 1226-086X; 1876-794X
• DOI: 10.1016/j.jiec.2023.06.018

[Display omitted] •CO2 is used to recover the residual oil from the geological reservoirs via EOR methods.•The insufficient amount oil recovered by CO2 flooding is associated with the low viscosity of CO2.•The low viscosity of CO2 results in CO2 viscous fingering, gravity override and unfavourable mobility.•CO2 thickeners help to mitigate the problem of low viscosity of CO2. Carbon dioxide (CO2) has been utilized to recover the residual oil from the geological reservoirs through enhanced oil recovery (EOR) methods for over 50 years. Despite its long history of success as an EOR technique, CO2 flooding recovers only about 20–40% of the original oil in place (OOIP) from the geological reservoirs. The small amount of oil recovered by CO2 flooding is associated with the low viscosity of CO2 injected into the reservoir, resulting in CO2 viscous fingering, CO2 gravity override and unfavourable mobility. To address these problems, the CO2 viscosity needs to be enhanced considerably using CO2 thickeners or viscosifiers. Despite more than five decades of intensive research work in formulating and identifying effective CO2 thickeners such as polymers, surfactants, small molecules and nanoparticles; as yet none of these chemicals can be regarded as effective CO2 thickeners for EOR field applications. Thus, CO2 thickener is an interesting research topic for future studies to come up with effective and affordable CO2 thickeners for EOR field applications. This article presents the recent developments in CO2 thickening technologies in EOR. Furthermore, the CO2 thickening mechanisms, screening criteria, field scale applications, challenges and future research directions on CO2 thickeners are evaluated.