Simulation of CO2 Injection for EOR and Sequestration, and Investigation of Effective Operational Parameters - Case Study

Recognizing the most influential operational parameters and quantifying their effects in CO2 injection process by commercial software and validated compositional reservoir model can play an important role in optimizing the development scenarios. The most important operational parameters are injected CO2 volume, injection rate, location and number of injected wells, perforated intervals, GOR constraint of production wells, and CO2 solubility in the aquifer. Simulation results have shown that increasing the injected volume of CO2 causes increase in storage capacity, but not in the oil recovery factor necessarily. The most significant parameters on oil recovery factor are injection rate and perforated intervals. Injection in lower layers increases the recovery factor and storage capacity simultaneously. In field-scale simulation, injection pattern, well spacing and injection rate should be optimized concurrently. CO2 solubility in aquifer and limiting the production wells with GOR constraint increases the storage capacity and reduces the oil recovery factor. Finally, at the best scenario, secondary recovery factor obtained by continuous CO2 injection is around 7.5%, and CO2 storage capacity is 33 BSm3 equal to 60 MM metric Ton. Economical evaluation indicates that the best case scenario has IRR and NPV of 37% and 8 BUSD, respectively.