Objective and hypothesis
The injecting of large quantities of CO2 into the subsurface can only be accomplished if the transmissivity of the near well environment does not severely degrade during the injection period. Due to the risk of salt clogging, one of the important phenomena to consider when supercritical CO2 is injected through a high-saline aquifer is salt precipitation from the formation water. However, a lack of knowledge about the process renders unreliability the prediction of the phenomena, the interplay with fluid flow, the dependence on injection scenarios and the presence of impurities in the CO2 stream unreliable. Therefore, this project aims to establish safe operational windows for the storage site operators, where injectivity is unhampered by the precipitation processes.

Approach
To establish safe operational windows, the project obtains real-time observations of the salt precipitation in experiments. This enables the definition of mechanistically sound, mathematical descriptions for how the processes unfold and finally simulate their impact during CCS for the Stenlille storage sites and injection scenarios, as well as the outcome of possible mitigation measures. The project leverages the experience of two highly esteemed laboratories: the DTU laboratory and the GEUS Core Analysis Laboratory.

Expected impact/output
By establishing safe operational windows, the project can advance CCS standardisation for formations in Stenlille and similar locations. This project’s model deepens the understanding of salt precipitation’s impact on injectivity. Its successful equipment and procedures could become industry standards for CO2 storage optimisation. Finally, optimising onshore carbon storage facilities in Denmark expands storage capacity, which enables domestic and imported CO2 storage as well as boosting the economy.