Assessment of Well Integrity for Repurposing O&G Wells for CO ₂ Storage─Essential Safety Considerations

Wells that develop leaks due to integrity issues can pose serious risks to both the environment and human health, particularly if they release previously captured CO₂ back into the atmosphere or contaminate freshwater aquifers. Ensuring reliable underground storage, therefore, presents a significant challenge in well integrity. The injected CO₂ can lead to substantial corrosion of metal materials and cement within the well. Moreover, the quality of cementation may deteriorate due to improper cement placement or changes in its mechanical properties arising from the well's operational activities. Identifying, quantifying, and mitigating this corrosion, along with assessing cementation quality, are pivotal for maintaining satisfactory well conditions. This study proposes solutions, through a literature review, that focus on material selection and the composition of CO₂ flow. It emphasizes essential considerations for a preliminary evaluation of both active and suspended wells for their reuse in CO₂ injection and storage in CCS operations. Conducting a systematic literature review has been crucial in identifying the key factors for assessing wells suitability for CO₂ injection. The outcome is a flowchart designed for evaluating active and suspended wells, encompassing a qualitative and initial analysis of critical factors such as cement integrity, corrosion, CO₂ flow composition, and material compatibility. If the recommended actions do not resolve the issues with a well, it should be plugged and abandoned.