MODELING

This research focuses on modeling and simulating CO₂ injection and storage in a depleted sandstone reservoir using the CMG-GEM compositional simulator to evaluate the potential of geological carbon sequestration as a sustainable emission reduction strategy. A 3D reservoir model was constructed based on available structural and petrophysical data to replicate the dynamic behavior of CO₂ during and after injection. The simulation was performed under varying pressure and compositional conditions to assess injectivity, storage capacity, and reservoir response over a 69-year period. Results revealed effective CO₂ migration through the formation, with plume dispersion influenced by permeability variations across the ten layers. The estimated total CO₂ storage capacity of the reservoir was approximately 136,863 tonnes, indicating substantial potential for long-term containment. Pressure analysis showed a gradual and controlled buildup within safe limits, confirming caprock stability and the absence of leakage or fracture risk. Additionally, the molality plots demonstrated consistent distribution of CO₂ within the formation, with concentration stabilization after a five-year halt and resumption of injection in 2050, reflecting strong reservoir retention. Overall, the study confirms that the selected depleted reservoir can serve as a viable site for CO₂ sequestration. The findings also highlight the importance of optimizing well placement, incorporating residual and mineral trapping mechanisms, and extending simulation timeframes to improve prediction accuracy and long-term storage performance.

Gas condensate is very important reservoir fluid because it is made up of a mixture of low density mixture of hydrocarbon in which during processing it yields other products like associated dry gas and also creates condensate oil after being extracted. A condensate reservoir exhibits a unique characteristic which make it special and at the same time difficult to recover due to liquid banking which is formed as a result of pressure and temperature change during production. In other to optimize production in a gas condensate reservoir proper attention must be paid to its phase behavior.The objective of this study is to model a gas condensate reservoir. The approach used in this study is the compositional analysis (the use of software) to determine the components of the gas condensate and compared with experimental approach which involve constant composition expansion (CCE) test and constant volume depletion (CVD) test. CCE provides information about the dew point, relative volume of fluid and condensate liquid while CVD provides information about condensate oil saturation and condensate oil and gas recovery. Finally the empirical method which is the equation of state model (EOS) using a simulation software to match the results gotten from the different approaches. The result of the study from compositional analysis simulation shows that the P-T diagram of critical pressure, temperature can be constructed and its results shows that composition significantly varies as a function of fluid phase behavior and also affects the producing sequence of a condensate reservoir. It as well pointed out the need to conduct more studies on characterization in other to be able to make the best recovery choice for optimal production from a gas condensate reservoir