Advancing offshore CCS monitoring with chemical tracers – the value of knowledge sharing within the international CCS community

The value of knowledge sharing within the close-knit international CCS community has been proven by a research paper published this month by SCCS researchers focused on using chemical tracers to monitor for seabed leaks at offshore CCS projects.

Our work began in 2013 when I was working on a UKCCSRC-Call 1 funded project together with Dr Mark Naylor and Dr Stuart Gilfillan. The project assessed potential future work at QICS, the world’s first CO₂ release experiment that simulated CO₂ leakage into the marine environment. To inform this, we consulted the CCS community for their thoughts on research priorities for future releases. Dr Linda Stalker, one of the leading experts in using tracers for CCS, responded to the consultation, expressing interest and capabilities in trialling tracers at possible future experiments at QICS.

During the project, our team worked together to explore whether using of tracers at future marine releases would be feasible, including constraints and cost implications posed by the marine environment, like the logistics of sampling, the fate and impact of tracer chemicals, and possible legislative barriers. The work led to a research exchange in 2015/16, when I visited Linda as part of a UKCCSRC-funded Early Career Researcher exchange to the National Geosequestration Labs in Perth, Australia.

Through close collaboration, we identified key challenges to using tracers for offshore monitoring, and critical uncertainties that made it difficult to select the most appropriate tracers and make reasonable cost estimates. These include issues of longevity of tracer chemicals over long timeframes, their behaviour in marine sediments, CO₂ bubble streams and in dissolved CO₂ as well as possible environmental effects and how best to sample the tracers. These uncertainties directly affect the selection of appropriate tracers, the injection programme and concentrations necessary for their reliable detection, and appropriate sampling approaches. Our recently published paper suggests a programme of work that would address these uncertainties and inform possible future field trials.

Meanwhile, the STEMM-CCS project was borne. The H₂020 funded project launched in 2016, and will deliver new approaches, methodologies and tools for monitoring of offshore CCS sites. Importantly, this includes a CO₂ release experiment in the North Sea, at the Goldeneye prospective CO₂ storage site.

One of the aims of the project is to develop effective methodologies for quantifying CO₂ fluxes in the marine environment, including the use of chemical tracers. Postdoc Dr Anita Flohr is undertaking research in this area on the STEMM-CCS programme, and became aware of the work through the IEAGHG monitoring network.

Anita says: “If a tracer qualifies for commercial-scale monitoring programmes of CO₂ storage, it is not only a matter of its physical and chemical properties but also a matter of the logistics, technology and costs behind the sampling, processing and analysis. To me the significance of this review is that it summarises the key findings of CCS-related tracer research, firstly, by addressing these diverse aspects and, secondly, by translating this to the challenges of monitoring of CO₂ storage in the marine environment. It’s a great contribution and will be a helpful guidance on aspects to consider for the STEMM-CCS tracer approach.”

The inception and development of the recently published paper and its direct implications on the planning of STEMM-CCS research programme therefore shows the strength of international collaboration and encouraging a networked CCS community. It also shows the value of “real-life” field activities, such as QICS, that are harder to measure, since they not only move knowledge forward and highlight issues for future projects to address, they build international interest and capability for future projects.

Read the paper

Roberts, J. J., Gilfillan, S. M. V., Stalker, L., and Naylor, M., 2017, Geochemical tracers for monitoring offshore CO₂ stores: International Journal of Greenhouse Gas Control, v. 65, no. Supplement C, p. 218-234.

https://www.sciencedirect.com/science/article/pii/S1750583617301081

STEMM-CCS Project: https://www.stemm-ccs.eu

QICS: https://www.bgs.ac.uk/qics/home.html

NGL: https://ngl.org.au

Twitter handles:

@STEMM_CCS_EU

@stugilfillan 

@StalkerLinda

@the_JenRoberts