Multiphase flow dynamics and flow pattern analysis in production wellbore during subsurface carbon storage

Understanding the multiphase transport behavior in production wells is critical for the safety and efficiency of Carbon Capture, Utilization, and Storage (CCUS) systems. In this study, a wellbore numerical model was established using computational fluid dynamics (CFD), incorporating the CO 2 -induced variations in produced-fluid properties. Based on the simulation results, a novel flow-pattern identification method tailored for CO 2 Enhanced Oil Recovery (CO 2 -EOR) production wells was proposed. In addition, by integrating this identification method with an interphase mass-transfer model for the wellbore, a dedicated pressure-drop prediction model for CO 2 -EOR production wells was developed. Finally, numerical simulations were conducted to investigate how key factors, including CO 2 content, water cut, and gas–liquid ratio, govern flow pattern transitions and pressure-gradient evolution, thereby identifying the major controlling factors of multiphase flow in CO 2 -EOR production wellbores. The findings provide a theoretical basis for optimizing flow assurance strategies in complex subsurface carbon storage and utilization projects.