Geological sequestration of CO2 requires knowledge of the flow properties of fault-related fracture networks in the low-permeability shale caprocks that overly most of the considered storage sites. A safe, sustainable and economical storage operation requires a profound understanding of these risks, recognising that quantification is challenging due to the many length and time scales involved and the very limited availability of data. These risks were addressed in the ACT project DETECT: Determining the risk of CO2 leakage along fractures of the primary caprock using an integrated monitoring and hydro-mechanical-chemical approach and the ERC project SECURe: Subsurface Evaluation of CCS and Unconventional Risks. 

 

Here, we present the integrated modelling workflow developed and applied within DETECT and SECURe. We combine laboratory experiments to obtain single-fracture stress-sensitive permeabilities; single-fracture modelling for stress-sensitive relative permeabilities and capillary pressures; fracture network characterisation and modelling for the primary and secondary caprocks; upscaling of properties and constitutive functions in fracture networks to be able to carry out full compositional flow modelling at the field scale.