Regional Screening of Secure CO2 Geological Storage Beyond Oil and Gas Fields: A Criteria-based Assessment of Colombian Sedimentary Basins

CO₂ geological storage, a core component of CCS technologies, is a key pillar of climate change mitigation and the reduction of CO₂ emissions within future low-carbon energy systems. Geological suitability constitutes the primary prerequisite for long-term to permanent subsurface CO₂ containment. Consequently, the identification of safe storage sites requires robust geological screening to ensure CO₂ containment and caprock integrity, while minimizing potential environmental risks associated with CCS operations. In many countries, subsurface data availability ranges from heterogeneous to scarce, particularly with respect to CCS-specific parameters. As a result, numerous sedimentary basins remain underexplored not only for energy resources but, more importantly, for their potential for CO₂ geological storage. Hence, regional-scale prospectivity assessments are essential to support to support early-stage planning and strategic decision-making. Importantly, the potential for CO₂ geological storage should be assessed independently of existing oil and gas activites, without excluding them, in order to avoid understimating national CCS opportunities. This study presents a systematic regional screening assessment of the CO₂ geological storage potential of Colombian sedimentary basins. A total of 23 basins were evaluated using a consolidated set of 21 criteria derived from established CCS site screening, selection, and characterization guidelines. The criteria ordering and assessment strategy were explicitly designed to reflect current limitations in data availability, prioritizing parameters that can be reliably evaluated at the basin scale under a contingent resources scenario and during the early stages of CCS planning. Favorability levels were calculated based on the degree of criteria fulfillment, allowing the classification of basins into high, moderate, and low prospectivity categories for CO₂ geological storage. The results identify six sedimentary basins with high prospectivity for secure CO₂ geological storage (>80% favorability): Catatumbo, Caguán–Putumayo, Eastern Llanos, Guajira, Guajira Offshore, and Lower Magdalena Valley. These basins exhibit suitable depth ranges, favorable reservoir–seal configurations, relatively stable tectonic settings, and existing infrastructure that may collectively support secure CO₂ geological storage operations. Seven additional basins classified as having moderate prospectivity are also identified as relevant candidates, as their limitations are largely associated with data scarcity or low exploration maturity rather than intrinsic geological conditions. This regional-scale assessment demonstrates that Colombia hosts multiple high prospectivity areas beyond oil and gas fields with significant potential for CO₂ geological storage that remain underconsidered in current mitigation strategies. The findings indicate that the six prospective basins should be prioritized for further site characterization, risk assessment, and capacity estimations, thereby contributing to the future scalable and effective deployment of secure storage sites. Alongside geological suitability considerations, the results suggest that the principal barriers to CCS deployment in Colombia may not be predominantly technical or economic. Instead, social acceptance, public perception, and the absence of regulatory frameworks emerge as critical challenges, as similarly observed in other Latin American countries. The study underscores that decision-making strategies must recognize CCS as a fundamental component of  future integrated energy systems rather than as isolated technological solutions. Addressing these social and governance dimensions is essential to translate geological storage potential into viable CCS projects in the near term.