Repurposing Depleted Hydrocarbon Assets for Subsurface Carbon Sequestration: Mechanical Integrity and Geochemical Risks

Abstract

Depleted oil and gas fields are frequently cited as the lowest-risk candidates for deep geological carbon storage due to the availability of seismic surveys, well log data, and verified structural trapping integrity. However, injecting supercritical carbon dioxide introduces severe mechanical and geochemical stresses that distinguish carbon sequestration from standard water injection or secondary recovery projects. This article reviews the primary failure pathways associated with legacy wellbore cement degradation, reservoir cooling stresses, and caprock geochemical dissolution, emphasizing why brownfield sites demand stringent re-entry and verification protocols before injection begins.