Underground geological sequestration of carbon dioxide (CO2) and its effect on possible enhanced gas and oil recovery in a fractured reservoir of Eastern Potwar Basin, Pakistan

Due to concerns over rising emissions of carbon dioxide (CO2) from fossil fuel utilization, there has been a strong emphasis on the development of a safe, economical, practical method of carbon capture utilization and storage (CCUS). One way to reduce these CO2 emissions is underground geological sequestration in depleted oil fields or exhausted reservoirs. CO2 injection into oil reservoirs is an established technology, these reservoirs not only offer the potential for high storage of CO2 but this process could also target a large amount of oil and gas recovery through a technique called enhanced oil recovery (EOR). The main objective of this research was to evaluate the storage potential of CO2 in the depleted oil field while also investigating the effect of CO2 injection on reservoir pressure maintenance, and additional oil and gas recovery, in the same field. This paper presented the model of CO2 flooding based on the CO2 displacement mechanism with different scenarios of natural depletion, CO2 injection, and water injection simulated by the ECLIPSE 300 reservoir simulator, and the results of different scenarios were compared. Results of this study showed the site selected for CO2 injection has the potential to store more than 9 billion cubic feet (BCF) of CO2 in each case and witnessed improved gas recovery, while also having a major effect on reservoir pressure maintenance where pressure increased from 2120 psi to 6584 psi. The finding of this work ought to help in preparing for future improvement in underground geological sequestration of CO2 in depleted fields with the same field specifications.