Rather than telling people that no CO2 will ever leak from a subsurface reservoir, geoscientists should rather use their expertise to explain that there are always risks associated with drilling wells and injecting fluids in the subsurface.
Even though this message might be a little more complicated to convey, it will prevent situations where the public will feel misled when a CO2 leak does occur in a future storage site.
This does not mean that no thorough screening is required to find the most suitable injection site and that CO2 can just be injected anywhere, but a 99% containment probability should not be the showstopper. At the end of the day, it is very much the question if the CO2 that leaks from a reservoir at around 2,000 m depth will ever make it to surface. In addition, even if it happens, is it a disaster? CO2 is not a toxic gas after all.
In that light, Jane Wheelwright’s comment during her short talk at SEISMIC 2023 was spot on. Geological studies cannot forever continue with the aim to de-risk a storage site towards a 100% probability of containment. It never will, especially combined with potential leakage paths along wellbores. Instead, let’s articulate geological risks better.
