Effects of injection well operation conditions on CO2 storage capacity in deep saline aquifers

For large‐scale CO2 geological storage (CGS) in deep saline aquifers, storing maximum possible amounts of CO2 over the project period is desirable. The ultimate storage capacity of a potential storage site is evidently a function of the static formation characteristics (e.g., formation porosity and thickness). However, it can be dramatically changed by the injectivity variations caused by the dynamic practices utilized during CO2 injection. Proper management of a CGS project implies operating the injection well at the optimal well operating condition or injection scheme that ensure optimal injectivity and hence improved ultimate storage capacity. Practically, the operating condition of the injection well is partly controlled by the amount of CO2 supplied by the emission source (e.g., power plant), which results in inevitable fluctuations/shut‐downs during the operation. In this work, we investigate the effect of different operating conditions of the injection well on the injectivity and the ultimate storage capacity of the aquifer. With CO2 injected continuously or intermittently, constant terminal‐rate and constant terminal‐pressure well operating conditions are studied. Next, we provide a simple net‐present value (NPV) analysis to evaluate the economic feasibility of adopting different injection schemes. The results are applied to a synthetic CGS project with injection history to investigate their implications. Finally, we present a sensitivity analysis to test the effect of varying the injection rate, the vertical permeability, and the formation dip angle on the dynamic storage capacity. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd.