Patterns Effect of CO2 Injection Impact on the Oil Production

Carbon Dioxide is regarded as one of the most widely utilized miscible gas injection to enhance oil recovery. Because of its accessibility, greenhouse effect, and ease achieving miscibility compared to other gases, its use has expanded considerably. As a result, miscible Carbon Dioxide injection is regarded as one of the most practical approaches globally. Given the declining oil reserves, most oilfields in Iraq need to enhance oil recovery as a part of long-term planning. In this paper, a reservoir model is built using different patterns, starting from building a geological model and then PVT modelling, where the matching was obtained between the laboratory data and the data calculated from the equation of state. The minimum miscible pressure was estimated by comparing correlations and the cell-to-cell method, yielding low error rates. Subsequently, a reservoir model was constructed utilizing five-spot patterns and peripheral patterns, as well as a seven-spot configuration. The simulation commenced in 2009 and extended to 2045, with injection occurring from 2025 to 2045 across layers 4 to 7, where ten injection wells were allocated for the five-spot pattern and peripheral patterns and 16 injection wells for the seven-spot configuration. This study concluded that the seven-spot pattern is better than the five-spot pattern and peripheral in oil rate and recovery but achieved the highest gas-oil ratio while the peripheral pattern gave lower oil rate and recovery and gas-oil ratio than the other patterns. the seven- spot pattern was chosen as the best in oil production.