CO2通过注采井壁泄漏造成携热介质CO2损失和地下水污染，制约CO2开采地热技术发展。CO2注采井壁渗透性演化机理是研究CO2通过注采井壁泄漏的关键科学问题。本研究以CO2开采地热注采井壁为研究对象，采用试验研究、理论分析和数值模拟相结合的技术手段，研究CO2开采地热条件下CO2与咸水在井壁裂隙中的流动过程，揭示井壁与高浓度CO2的化学反应机制，阐明高温-应力-CO2化学腐蚀共同作用影响井壁渗透性的机理，建立可定量描述井壁渗透性在高温、外部应力、CO2化学腐蚀共同作用下演化规律的数学模型。开展场地尺度CO2通过注采井壁裂隙泄漏的数值模拟，研究场地尺度井壁渗透性演化对CO2泄漏量的影响。研究成果将有助于科学认识CO2开采地热条件下CO2在注采井壁裂隙中的渗漏过程，为CO2开采地热项目的CO2泄漏风险评价提供理论依据和分析工具。

A major risk that needs to be considered in CO2 geothermal production is CO2 leakage through the CO2 injection well or production well intersecting the caprock above CO2 host formation. CO2 leakage through the fracture between the well and the caprock is the most common leakage pathway. In this work, experimental study, theoretical analysis and numerical simulation are combined to study CO2 and brine migration in the fracture between the well and the caprock. With the application of flow theory in rock joint, constitutive relation between normal stress and fracture permeability, and wellbore cement—CO2 interaction mechanism, combined with advanced material characterization techniques and numerical simulation, the mechanism of fracture permeability evolution induced by high temperature, normal stress and CO2 corrosion at the interface between the well and the caprock is revealed. A mathematical model is developed to describe the correlation between fracture permeability and influencing factors like temperature, normal stress and CO2 corrosion, and numerical simulations are conducted to investigate field-scale CO2 leakage along the CO2 injection well or production well, considering well permeability evolution. Research outcomes contribute to the understanding of CO2 migration in the fracture between CO2 well and caprock under CO2 geothermal production environment, and provide support for CO2 leakage risk assessment of CO2 geothermal production projects.