In the year 2030, Indonesia has set ambitious goals to produce 1 BOPD (Barrels of Oil Per Day) by employing secondary an tertiary recovery methods. Concurrently, Indonesia is committed to reducing GHG (Greenhouse Gas) emissions by a range of 29% to 41%. To attain these targets, the Indonesian government has initiated plans for the implementation of Carbon Capture and Storage (CCS) as well as Carbon Capture, Utilization, and Storage (CCUS) technologies. The CCUS technology is the most viable solution for Indonesia to increase oil production and reduce GHG emissions, as CCUS can enhance the recovery factor from 5% to 15% and reduce carbon emissions by 0.5 to 1.5 tons of CO2 per ton injected. This study was conducted in oil field located in East Java, Indonesia, which features a carbonate reservoir. This study utilized CMG GEM 2021 to analyze the impact of CO2 injection rate and the location of injection perforations as crucial parameters influencing the effectiveness of CCUS implementation. This analysis encompassed a sensitivity study involving various CO2 injection rates and perforation locations within the gas cap, oil zone, and aquifer zones. The outcomes of this sensitivity analysis were evaluated based on oil recovery factor, CO2 storage, and CO2 plume migration. The study concluded that the CO2 injection rate has an almost linear relationship with the oil recovery factor. Thus, higher rates of CO2 injection correspond to a more rapid horizontal migration of CO2 plume, thereby covering a wider area. Consequently, a larger number of wells experience CO2 breakthrough, resulting in reproduction of CO2 alongside oil and gas production. Furthermore, concerning the sensitivity analysis of perforation location, the highest oil recovery factor was observed in the oil zone perforations, reaching to 38.37%. This can be attributed to the increased contact between CO2 and oil within this zone. Conversely, the most effective location for CO2 storage was found to be the aquifer zone perforations, primarily due to the substantial CO2 trapped via residual and solubility trapping mechanisms, which are considered safer than structural trapping. The perforation location also influences the migration of CO2 plume, as there are variations in horizontal and vertical permeability across the different perforation zones. The CO2 plume tends to migrate through layer with higher permeability.