Volume 57

Analysis of Reservoir Damage Mechanisms Induced by CO2 Flooding and Research on Prevention and Control Strategies Li Binru, Song Hanxuan, Xue Pengcheng, Guo Jixiang

Abstract

The utilization of CO2 flooding for enhanced oil recovery not only represents an environmentally sustainable approach to greenhouse gas management but also serves as a critical technical strategy in reservoir development, functioning through the injection of CO2 to replenish formation energy and reduce crude oil viscosity, thereby enhancing fluid mobility. However, this process may induce reservoir damage through complex chemical-mineral reactions, including carbonation reactions with mineral dissolution, secondary precipitation blockages, and clay mineral expansion/migration. Additional detrimental mechanisms involve wettability alteration due to CO2 extraction of light components from crude oil, asphaltene deposition and organic blockage resulting from phase behavior changes during CO2-crude oil miscibility, and mechanical damage caused by exacerbated reservoir heterogeneity from CO2 viscous fingering in high-permeability zones. To address these challenges, comprehensive prevention strategies should be implemented: Reservoir adaptability evaluation must precede optimized CO2 injection scheme design through parameter optimization (e.g., pressure control, injection rate modulation, and water-alternating-gas (WAG) injection). Chemical interventions involving precipitation inhibitors, anti-swelling agents, or surfactants should be employed, complemented by pre-treatment acidizing for blockage removal and post-flushing microemulsion techniques. Given that CO2-induced reservoir damage constitutes a multifield coupling process involving chemical-mechanical-flow interactions, an integrated management strategy emphasizing proactive prevention and dynamic regulation should be adopted. This approach, grounded in thorough understanding of reservoir geological characteristics and CO2-fluid-rock interaction mechanisms, aims to achieve dual objectives of enhanced oil recovery efficiency and reservoir protection.

Keywords CO2 flooding, Enhanced oil recovery, Reservoir damage, Prevention and control strategies