Publication Overview
The agenda was structured in accordance with the 3 criteria with sessions on review of performance monitoring tools, data integration and demonstrating monitoring data conforms with predictive modelling, developing protocols and strategies to form a monitoring plan and monitoring of the outer envelope – demonstrating no leakage. There was also a discussion session on CCS in the CDM – what modelling is required for monitoring and a session on updates and permanent Installations; current and future activities. The meeting ended with a review of the main learnings taken from the meeting.
Publication Summary
Actual behaviour of the injected CO₂ conforms with modelled behaviour:
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.
No detectable leakage
This was mostly considered in the session on monitoring of the outer envelope. Traditional techniques include soil-gas and atmospheric monitoring as well as monitoring of shallow water sources. It is very important to capture the full natural variation of CO₂ and associated compounds in the baseline. There are issues with sampling and what points to measure. There are also areal methods to detect possible leakage, but these may not be able to quantify the CO₂, necessitating a 2 step approach to first locate the leak, and then quantify it. A new process based approach to soil monitoring was also presented, for which a baseline is not needed as the amount of exogenous CO₂ is derived from the ratios of CO₂ to other gases.
The excellent work and results from monitoring at the Ketzin project were highlighted throughout the meeting, and delegates visited the Ketzin project site.
Overall, there was much progress being made, with the increasing amount of monitoring results becoming available and providing good learnings and experiences from real projects. The use of risk assessments to define monitoring programmes was also demonstrated for real projects.
Presentations given can be found on the monitoring pages of the IEAGHG website: http://www.ieaghg.org/index.php?/20110217242/7th-monitoring-network-meeting.html
