Abstract
In the pursuit of carbon neutrality, the CO2-enhanced oil recovery provides dual benefits by enabling both carbon sequestration and incremental oil production. However, its application is limited by high minimum miscibility pressure. CO2-philic and oil-affinitive surfactants have emerged as an effective, low-dosage, and cost-efficient strategy to reduce the minimum miscibility pressure. In this study, macroscopic phase behavior experiments combined with molecular dynamics simulations were employed to systematically elucidate the influence of multiester-head surfactants on CO2–oil miscibility. Using a modified pressure–volume–temperature apparatus equipped with optical power monitoring, we determined that multiester-head surfactants reduced the first-contact miscibility pressure by 13.17%–20.18%. Surfactants featuring cyclically arranged CO2-philic ester groups demonstrated superior performance compared with their linear counterparts, achieving optimal efficacy with four ester groups. Multiester-head surfactants exhibit alkane chain-length-dependent mechanisms for enhancing CO2–alkane miscibility: In light hydrocarbons, solubilization occurs through localized micellar structures; In medium-chain systems, a three-stage synergistic mechanism operates, involving interfacial tension reduction, CO2 transport, and demulsification via demi cell formation. In mixed light–heavy systems, light hydrocarbons serve as "bridges" to overcome mass transfer barriers for heavy components, thereby activating surfactant amphiphilicity. These findings offer both theoretical and experimental support for the rational molecular design of high-performance CO2-philic surfactants, thereby advancing carbon capture, utilization, and storage as well as CO2-enhanced oil recovery and geological sequestration technologies.
Recommended Citation
N. Xu et al., "Mechanism of Improved Miscibility of CO2–Oil Systems by Multiester-Headgroup Surfactants," Energy and Fuels, vol. 40, no. 16, pp. 8717 - 8739, American Chemical Society, Apr 2026.
The definitive version is available at https://doi.org/10.1021/acs.energyfuels.6c00210
Department(s)
Geosciences and Geological and Petroleum Engineering
Second Department
Chemical and Biochemical Engineering
International Standard Serial Number (ISSN)
1520-5029; 0887-0624
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2026 American Chemical Society, All rights reserved.
Publication Date
23 Apr 2026
Included in
Biochemical and Biomolecular Engineering Commons, Geology Commons, Petroleum Engineering Commons
