Wellbore leakage risk management in CO2 geological utilization and storage: A review

Abstract

CO₂ geological utilization and storage (CGUS) is an important technology to achieve a deep cut of global CO₂ emissions. CO₂ leakage from the subsurface may impair the performance of CGUS projects, and the CO₂ leakage through wellbores is the most common leakage pathway. This paper proposes a workflow for wellbore CO₂ leakage risk management, and the workflow consists of the following steps: i) leakage risk identification; ii) leakage risk evaluation; iii) leakage risk monitoring; iv) leakage handling. Representative approaches in each step of the workflow are systematically reviewed. Key challenges of wellbore CO₂ leakage risk management include: lack of effective detection and evaluation approaches to tackle the CO₂ leakage risk induced by cement failure; lack of low-cost acid resistance alloys and CO₂-resistant cement; lack of automated monitoring systems that could enable automated shutdowns of the wellbore whenever certain warning criteria are met.