Molecular Dynamics of CO₂ Stripping Oil on Quartz Surfaces

The CO2-enhanced oil recovery (EOR) technology has the dual significance of enhancing oil recovery and realizing carbon storage in onshore and offshore oil and gas exploitation. This study investigates the adsorption of crude oil components on quartz surfaces and the microscopic mechanisms of CO2 stripping from crude oil using molecular dynamics simulations. A four-component model representing C6H14, benzene, resins, and asphaltenes was constructed to simulate the oil phase, while the quartz surface model was created using Materials Studio. Simulations were conducted under different temperature conditions to understand the distribution and adsorption behavior of crude oil components, as well as the impact of CO2 on the oil film at pressures up to 10 MPa. The results indicate that the resin–asphaltene interactions are significantly weakened at elevated temperatures, affecting the adsorption capacity. Furthermore, CO2 stripping primarily extracts light components such as C6H14 and aromatic hydrocarbons, while heavy components remain in the oil phase. The highest extraction efficiency and expansion effect of CO2 were observed at 35 °C, demonstrating optimal conditions for enhanced oil recovery through CO2 flooding. These findings provide insights into the effective use of CO2 for crude oil extraction and its interactions with oil components on a quartz substrate, which is crucial for optimizing CO2-enhanced oil recovery operations.