Heavy oil reservoirs, such as Field-A in the Gulf, have become increasingly important for oil companies due to the rising demand for oil and the decline of conventional fields. Field-A, characterized by its high-viscosity oil (2424 cp) and low API gravity (14°), poses significant challenges for extraction using conventional methods like primary and secondary recovery. The reservoir spans 3637 ft by 855 ft with a thickness of approximately 130 feet, an average porosity of 19%, and a permeability of 1501 millidarcies. These factors make primary and secondary recovery techniques largely ineffective, necessitating the use of Enhanced Oil Recovery (EOR) methods, specifically steam flooding, to improve extraction efficiency. This thesis focuses on optimizing steamflood parameters for Field-A using the CMG simulation software. Key parameters, including the well pattern configuration of injection/production wells, well spacing, steam injection rate, steam quality, and injectors' perforation intervals, were thoroughly evaluated. The manual optimization process using CMG-STARS involved a step-bystep testing of each parameter, with the others held constant at their base case values, and sequentially updating the optimized parameters throughout the process. During the optimization, several issues related to steamflooding were encountered and mitigated, such as premature water breakthrough and steam override, both of which have the potential to significantly reduce the oil production and NPV. Through careful optimization, these issues were mitigated, enhancing the overall performance of the steamflood operation.Towards the conclusion of the project, the CMGCMOST software was employed to run 450 simulations, with parameters randomly selected for optimization. The results from both the manual optimization and the CMOST simulations were compared and were found to have nearly identical outcomes. Based on this comparison, the best model was selected, featuring a line drive configuration with 225 ft well spacing, steam injection rates of 227 CWE/day/well, steam quality of 54%, and a perforation interval at layers 2, 4, 5, and 7 of the reservoir. This model was identified as the most promising, with an expected NPV of 217.3 million USD. The chosen optimal model was subsequently used to conduct sensitivity analyses on various geological and economic parameters.