Subsurface Constraints for CO2 Specifications in Geological CCS: A Focus on the Middle East

As part of global decarbonization efforts, new subsurface CO2 injection projects in Middle Eastern carbonate reservoirs are being developed. To reduce costs, there is a growing need to design CO2 specifications that tolerate certain levels of impurities. In this study, we evaluate the impact of injecting CO2 streams containing impurities into carbonate reservoirs using a combined thermodynamic and reservoir flow modelling approach. Our results highlight the role of oxygen-containing impurities and indicate that CO2 specifications should prioritize the relative proportions of impurities, rather than their absolute concentrations, to ensure safe and effective long-term storage.