Depleted Reservoirs as CO2 Storage Sites: A Review of Frameworks and TECOP Considerations in the Niger Delta

Abstract Niger Delta is a mature hydrocarbon bearing region of Nigeria, comprising of nine states with proven accumulations. Over the years, due to numerous exploration and production of these accumulations vast subsurface data and studies have been carried out defining it as a mature province. While it serves as a major source of fossil energy which sufficiently contribute to the energy demand in Nigeria, it however, comes with its environmental threats and pollution due to CO2 emission. Regulations based on penalties alone for emissions from gas flaring remain insufficient in addressing this issue, hence, requiring a more sustainable solution. With the infrastructural developments and rich subsurface data in Niger Delta, therefore, places it on a good pedestal for the implementation of Carbon Capture, Utilisation and Storage (CCUS) project. CCUS having shown field scale feasibility in some regions of the world, several studies are currently on-going on its implementation in the Niger Delta, with focus on frameworks and recommendations for its implementation. Hence, in this study, a detailed review on existing frameworks for screening and converting depleted oil and gas reservoirs into secured CO2 storage sites was conducted. This review study cross-examined published studies and methods in candidate reservoir selection, technical feasibility assessment, risk management, and monitoring strategies, emphasising their applicability and limitations in the Niger Delta context. Building on this analysis, deeper areas of consideration were highlighted using the Technical, Economic, Commercial, Operational, and Political (TECOP) evaluation lens. The review recommended that successful CCUS deployment in the Niger Delta required integrated strategies that combined technical rigor with economic feasibility, commercial pathways, operational readiness, and political support. The findings will provide industry stakeholders, policymakers, and researchers with a structured roadmap for advancing secure, effective, and commercially viable CO2 storage projects in the region.