Publication Overview
The theme for this year’s meeting centred on the 3 criteria for transfer of responsibility in the EU directive:
- Actual behaviour of the injected CO₂ conforms with the modelled behaviour.
- No detectable leakage.
- Storage site is evolving towards a situation of long-term stability While the directive is European, the aims are applicable and necessary to all worldwide storage projects. There is no information yet from experience for the 3rd point, which also derives from the first two, so the focus was on the first 2 aims.
Publication Summary
Seismic detection limits have been discussed for Otway, Ketzin and Nagaoka and it is clear that repeatability is key to be able to compare results over time and with modelling data. At Ketzin, monitoring results show that the plume migrated to a lesser extent than expected from the initial modelling due to the heterogeneity in the subsurface. This is within expected limits; however, history matching has been carried out since to improve the model. It will always be the case that the models improve with more information, but a range of models may show the expected plume limits. Breakthrough was also later than detected, which was unexpected, but not negative. This all shows how important it is to define monitoring and performance indicators. The talks from In Salah on In Sar show how even excellent datasets can have non-unique explanations. It can also be seen that combinations of tools can reduce overall uncertainty. Results from pilot sites are necessary for understanding and demonstrating processes as well as testing monitoring tool capabilities.