To verify successful long-term carbon dioxide storage, an improved understanding of geological leakage risks across the primary caprock but also the shallower overburden is critical. While diffusive and advective matrix leakage can be considered to take place at low to moderate rates, especially fault-related fracture networks require an improved understanding. Faults can act as flow barriers and traps in reservoirs but also as leakage pathways into the shallow overburden. Being able to fully characterise fault and fracture networks, in terms of fracture permeability, fracture density, connectivity, aperture size and stress regime, can allow us to more accurately identify, analyse and model the bulk properties (e.g. transport, strength, anisotropy) and, therefore sealing behaviour, of faulted and fractured geological storage sites.