Theoretical modeling of the effect of temperature on CO 2 injectivity in deep saline formations

• Published in: Greenhouse gases: science and technology 2020-02, Vol.10 (1), p.4-14
• Main Authors: Sokama‐Neuyam, Yen Adams, Adu‐Boahene, Francis, Boakye, Patrick, Aggrey, Wilberforce Nkrumah, Ursin, Jann Rune
• Format: Article
• Language: English
• ISSN: 2152-3878; 2152-3878
• DOI: 10.1002/ghg.1951

Well injectivity and storage capacity defines the storage potential of a CO 2 capture, utilization, and storage (CCUS) facility. Formation temperature has high impact on the phase behavior and flow properties of CO 2 such as density and viscosity. The effect of temperature on CO 2 injectivity, especially in the wellbore injection inlet, is not well understood. We investigated the thermal behavior of CO 2 from the wellhead to the reservoir using simple theoretical models that capture the major heat transfer mechanisms. The effect of CO 2 injection flow rate and injection time on the temperature of CO 2 were studied. We found that for the same initial CO 2 injection temperature and formation intake temperature, the injected CO 2 in the well is cooler than the surrounding formation from the wellhead to the bottomhole. The temperature difference increased with increasing injection flow rate and injection time. The results show that although CO 2 may attain supercritical state at bottomhole, the temperature difference between CO 2 in the wellbore and the reservoir could be significant. The results also suggest that CO 2 could attain thermal equilibrium with the reservoir at a flow distance of about 600 ft into the formation depending on the injection flow rate and reservoir temperature. The thermal disequilibrium of CO 2 in the wellbore vicinity where fluxes are also high could affect CO 2 injectivity and the mobility of CO 2 during CCUS and enhanced oil recovery (EOR) operations. The present findings provide vital understanding of the effect of thermal instability on CO 2 injectivity especially in the wellbore injection inlet. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd.