The increasing deman‎d for enhanced oil recovery from mature an‎d complex reservoirs has made carbon dioxide (CO₂) injection a key EOR technique. This study presents a numerical investigation of immiscible CO₂ injection using the ECLIPSE 100 simulator, focusing on the influence of reservoir heterogeneity, injection pressure, oil properties (API gravity an‎d viscosity), injection timing, well placement patterns, an‎d well scheduling. A series of simulation cases were conducted to isolate the effect of each parameter while maintaining consistent reservoir geometry an‎d rock properties. Results show that homogeneous reservoirs exhibit more uniform displacement an‎d delayed gas breakthrough, whereas heterogeneous reservoirs suffer from early channeling an‎d bypassed oil. Moderate injection pressures (around 5000 psi) an‎d optimized well schedules provided the best balance between production rate an‎d sweep efficiency. Lighter oils (higher API, lower viscosity) responded more favorably to CO₂ injection, while heavy oils experienced poor recovery. Early injection improved ultimate recovery, an‎d the five-spot well pattern achieved the most effective areal sweep. These findings emphasize the importance of tailoring CO₂ injection strategies an‎d well scheduling to reservoir characteristics an‎d operational conditions to optimize oil recovery an‎d improve displacement efficiency in heterogeneous reservoirs.

حميدرضا شاه وردي

محسن محمدي , روح اله هاشمي