Quantifying the risk of CO₂ leakage along fractures using an integrated experimental, multiscale modelling and monitoring approach

Existing CO₂ storage sites have illustrated that intact low-permeability mudrocks are effective barriers to avoid upward migration of CO₂ from the storage complex. However, widespread deployment of Carbon Capture and Storage (CCS) as a means of climate change mitigation requires gigaton-scale CCS, rather than the few current megaton projects, to be deployed near large point sources of CO₂. In the future, geological storage sites with faulted caprocks cannot always be avoided. We therefore need to rigorously assess geological leakage risks for CCS and specifically improve our understanding of multi-phase fluid migration in faulted and fractured caprocks. The DETECT research program will provide new insights by integrating experimental characterization with multiscale modelling of the combined hydrochemical, hydromechanical and clay swelling and shrinking effects in faulted and fractured mudstones. The purpose of the models is to establish determine realistic flow rates across fractured and faulted mudstone caprocks, to identify existing monitoring tools capable of detecting such fluid migration. Based on these quantitative leakage scenarios, risk and mitigation bow-tie analyses are developed with which suitable and cost-effective monitoring tools can be identified.