InterPore2026

Microscopic phase transition characteristics of condensate gas and molecular mechanisms of CO2 injection for enhanced recovery

22 May 2026, 15:30

1h 30m

Poster Presentation (MS09) Pore-Scale Physics and Modeling Poster

Speaker

Han Xu (Chengdu University of Technology)

Description

Condensate blockage in gas reservoirs restricts the ultimate recovery factor, and the microscopic phase behavior of condensate gas represents a fundamental scientific challenge for preventing and mitigating condensate blockage damage. Currently, the molecular-scale mechanisms governing condensate gas depletion phase transitions and CO2 injection for enhanced oil recovery (EOR) remain poorly understood. In this study, molecular simulation methods were employed to construct a binary ethane/n-octane condensate gas system and develop a simulation method for condensate gas phase transitions. The evolution of condensate gas phase behavior and molecular mechanisms during depletion and CO2 injection processes were investigated. The results indicate that during depletion, n-octane exhibits a "dispersion-aggregation-evaporation" behavior, with its diffusion coefficient significantly reduced in the aggregated state. In contrast, ethane maintains a dispersed gas-phase state while its diffusion capability continuously increases. CO2 molecules enhance the diffusion coefficient of n-octane, reduce the system viscosity, and increase the system pressure, which results in a shift of n-octane density distribution from a single-peak aggregated state to a multi-peak dispersed state, thereby significantly inhibiting condensate accumulation. The greater the CO2 injection, the more pronounced the inhibition of n-octane aggregation, leading to enhanced homogenization within the condensate gas system. This study provides molecular-level insights into the complex phase behavior and enhanced recovery mechanisms in condensate gas reservoirs during depletion and CO2 injection processes, thereby providing theoretical guidance for the design and optimization of condensate gas reservoir exploitation strategies.