TY  - EJOU
AU  - Jing, Bo 
AU  - Zhu, Yuejun 
AU  - Zhao, Wensen 
AU  - Huang, Bo 
AU  - Tang, Engao 
AU  - Xiao, Anfeng 
AU  - Dong, Mingda 

TI  - Performance Evaluation of Gas-Soluble Surfactants for CO<sub>2</sub> Injection Development in Tight Oil Reservoirs
T2  - Energy Engineering

PY  - 
VL  - 
IS  - 
SN  - 1546-0118

AB  - To investigate the applicability of different gas-soluble surfactants in CO<sub>2</sub> miscible flooding for tight oil reservoirs and clarify the underlying mechanism of their enhanced oil displacement, this study first employed the cloud point pressure method to determine the solubility of surfactants in supercritical CO<sub>2</sub> under reservoir temperature, thereby identifying the pressure threshold for their stable dispersion. Subsequently, a falling-ball viscometer and an interfacial tension meter were utilized to analyze the viscosity reduction effect of surfactants on crude oil and the regulation law of CO<sub>2</sub>-crude oil interfacial tension under high-temperature and high-pressure conditions. Next, slim-tube displacement experiments were conducted to quantify the capacity of different surfactants to reduce the minimum miscibility pressure (MMP) of the CO<sub>2</sub>-crude oil system. Finally, core displacement experiments were performed to systematically evaluate the impacts of surfactants on key development performance parameters of CO<sub>2</sub> flooding, including oil recovery factor, oil production rate, and gas-oil ratio (GOR). The results demonstrate that surfactants with a higher number of CO<sub>2</sub>-philic functional groups and a higher degree of alkyl chain branching exhibit superior solubility in CO<sub>2</sub>, along with more significant effects on crude oil viscosity reduction and interfacial tension reduction, as well as stronger ability to lower MMP. Among the tested surfactants, AT-1, benefiting from the synergistic effect of its diester groups and isobutyl branches, can reduce the MMP to 39.4 MPa. Core displacement experiments indicate that compared with pure CO<sub>2</sub> flooding, AT-1-enhanced CO<sub>2</sub> flooding increases the oil recovery factor by more than 5 percentage points, while effectively delaying gas channeling and optimizing displacement dynamics. This study provides certain guidance for the further application of CO<sub>2</sub> flooding technology in tight oil reservoirs.
KW  - Tight oil reservoirs; gas-soluble surfactants; CO<sub>2</sub> flooding; interfacial tension; oil recovery factor

DO  - 10.32604/ee.2026.079022