Re-using the depleted reservoirs for CO2 storage offers advantages over saline aquifers because the geological characteristics required for CO2 storage have been pre-determined with high accuracy throughout the reservoir production life, plus a proof of secure containment. Additionally, re-using the production facilities and offshore platforms for the injection of CO2 would be economically and environmentally winning fact, which is the case in this study. This study, based on intensive bibliographic research, gave support to the MISE project regarding the challenges and concerns of CO2 storage in depleted oil and gas reservoirs and selecting the optimum solution for converting the offshore platform GREEN1 in the Adriatic Sea to be re-used instead of decommissioning.