The state of the art in monitoring and verification-Ten years on

In the ten years since publication of the IPCC Special Report on CCS, there has been considerable progress in monitoring and verification (M&V). Numerous injection projects, ranging from small injection pilots to much larger longer-term commercial operations, have been successfully monitored to the satisfaction of regulatory agencies, and technologies have been adapted and implemented to demonstrate containment, conformance, and no environmental impact. In this review we consider M&V chiefly from the perspective of its ability to satisfy stakeholders that these three key requirements are being met. From selected project examples, we show how this was done, and reflect particularly on the nature of the verification process. It is clear that deep-focussed monitoring will deliver the primary requirement to demonstrate conformance and containment and to provide early warning of any deviations from predicted storage behaviour. Progress in seismic imaging, especially offshore, and the remarkable results with InSAR from In Salah are highlights of the past decade. A wide range of shallow monitoring techniques has been tested at many sites, focussing especially on the monitoring of soil gas and groundwater. Quantification of any detected emissions would be required in some jurisdictions to satisfy carbon mitigation targets in the event of leakage to surface: however, given the likely high security of foreseeable storage sites, we suggest that shallow monitoring should focus mainly on assuring against environmental impacts. This reflects the low risk profile of well selected and well operated storage sites and recognizes the over-arching need for monitoring to be directed to specific, measureable risks. In particular, regulatory compliance might usefully involve clearer articulation of leakage scenarios, with this specificity making it possible to demonstrate "no leakage" in a more objective way than is currently the case. We also consider the monitoring issues for CO2-EOR, and argue that there are few technical problems in providing assurance that EOR sites are successfully sequestering CO2; the issues lie largely in linking existing oil and gas regulations to new greenhouse gas policy. We foresee that, overall, monitoring technologies will continue to benefit from synergies with oil and gas operations, but that the distinctive regulatory and certification environments for CCS may pose new questions. Overall, while there is clearly scope for technical improvements, more clearly posed requirements, and better communication of monitoring results, we reiterate that this has been a decade of significant achievement that leaves monitoring and verification well placed to serve the wider CCS enterprise. Crown Copyright (C) 2015 Published by Elsevier Ltd. All rights reserved.