First World Congress of International Consortium on Geo-disaster Reduction (1st ICGdR World Congress)

CO2 geological utilization and storage (CGUS) is a critical technology for achieving deep reductions in global CO2 emissions. A key challenge to its safety and long-term performance is the potential for CO2 leakage from the subsurface, with existing wellbores representing the most common pathway. To address this, a comprehensive workflow for managing wellbore CO2 leakage risk is essential. This systematic process involves four key stages: i) identification of potential leakage risks; ii) quantitative evaluation of their likelihood and consequences; iii) continuous monitoring of well integrity; and iv) implementation of measures to handle any confirmed leakage. Each step employs a suite of methodologies, from geophysical surveys and mechanical modeling to sensor networks and remediation techniques. This study also summarizes key technical challenges that hinder optimal risk management of wellbore leakage under CGUS conditions. i) There is a pressing need for more effective detection and evaluation methods specifically for leaks caused by wellbore cement and casing degradation. Material science limitations include a shortage of low-cost, acid-resistant alloys and advanced CO₂-resistant cement formulations. ii) The development of intelligent, automated monitoring systems—capable of triggering well shutdowns automatically when pre-set risk thresholds are breached—remains an urgent priority. Overcoming these hurdles is vital to ensuring the reliability and public acceptance of CGUS as a cornerstone of climate change mitigation.