A Computational Fluid Dynamics Simulation and Flow Patterns’ Prediction Model for Multiphase Flow in CO2-EOR Production Wells

Abstract

Abstract. To address the limitation that existing vertical wellbore flow pattern prediction models are not applicable to CO2-enhanced oil recovery (CO2-EOR) production wells in CO2-flooded reservoirs, a detailed flow field simulation model for CO2-containing oil wells was developed based on the principles of computational fluid dynamics. Considering the wellbore temperature, pressure, fluid composition, and physical properties, boundary conditions were established based on actual production parameters. The simulation was performed using an Euler–Euler multiphase flow model, ensuring consistency with the complex flow environment inside the wellbore. The flow pattern transition and its underlying mechanism were investigated when the produced fluid contains CO2. Based on the simulation results, a flow pattern map specific to CO2-containing oil wells was developed. The transition boundaries between different flow patterns were clearly defined, providing a detailed reference for flow regime identification under CO2 production conditions. Field validation using pressure profile measurements from a CO2-EOR well in the Tarim Oilfield demonstrates strong agreement between simulation and field data, with an average relative error of 4.2%. The research results provide a theoretical basis for designing lifting schemes and optimizing operating parameters in production wells, ensuring efficient and stable oilfield production.