Abstract:
Due to concerns over rising emissions from 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). CO2 is a considered as major threat for rapid environmental uncertainties. This tremendous amount of CO2 emissions also produces in Pakistan, and Pakistan as signatory of (COP21) has also pledged to decrease carbon footprint. One way for reduction of these CO2 emissions is underground geological sequestration in depleted oil field or exhausted reservoirs. CO2 sequestration in oil reservoirs is proven technology, these reservoirs not only offers potential of high storage of CO2 but this technique could also target the large amount of conventional and heavy oil which remain in reservoirs worldwide after conventional methods have been exhausted through a technique called enhanced oil recovery (EOR). In this study, numerical reservoir simulation is conducted using Eclipse Reservoir Simulator. The site selected for underground geological sequestration of CO2 emissions is depleted oil field of Pakistan having fractured reservoir with very high permeability. In this case, reservoir base case model with only water flooding in its previous history was compared with reservoir model established for underground geological storage of CO2 through three different injection rates, the main objective of this research is to evaluate storage potential of CO2 emissions in depleted oil field while also investigate the effect of CO2 injection on reservoir maintenance, additional oil recovery, and additional gas recovery of same field. The simulation result show site selected for CO2 injection has the potential to store more than 9 billion cubic feet (BCF) of CO2 emissions in each case, while also has the major effect on reservoir pressure maintenance, but improved in oil recovery was not observed due to deprived saturation of oil in oil bearing zones but it recovers additional marginal recovery of natural gas when compared to base case. The results of this study ought to help in preparing for future improvement in underground geological sequestration of CO2 research.
