Towards improved monitoring of offshore carbon storage: A real-world field experiment detecting a controlled sub-seafloor CO2 release
Anita Flohr, Allison Schaap, Eric P. Achterberg, Guttorm Alendal, Martin Arundell, Christian Berndt, Jerry Blackford, Christoph Böttner, Sergey M. Borisov, Robin Brown, Jonathan M. Bull, Liam Carter, Baixin Chen, Andrew W. Dale, Dirk de Beer, Marcella Dean, Christian Deusner, Marius Dewar, Jennifer M. Durden, Saskia Elsen, Mario Espósito, M. Faggetter, Jan Fischer, Amine Gana, Jonas Gros, Matthias Haeckel, Rudolf Hanz, Moritz Holtappels, Brett Hosking, Veerle A.I. Huvenne, Rachael H. James, Dirk Koopmans, Elke Kossel, T.G. Leighton, Jianghui Li, Anna Lichtschlag, Петер Линке, Socratis Loucaides, María Martínez-Cabanas, Juerg Matter, Thomas Mesher, Samuel A. Monk, Matthew C. Mowlem, Anna Oleynik, S. Papadimitriou, David Paxton, Christopher R. Pearce, Kate Peel, Ben Roche, Henry A. Ruhl, Umer Saleem, Carla Sands, Kevin Saw, Mark Schmidt, Stefan Sommer, James Strong, Jack Triest, Birgit Ungerböck, John Walk, Paul R. White, Steve Widdicombe, Robert E. Wilson, Hannah L. Wright, James Wyatt, Douglas P. Connelly
Abstract
Carbon capture and storage (CCS) is a key technology to reduce carbon dioxide (CO2) emissions from industrial processes in a feasible, substantial, and timely manner. For geological CO2 storage to be safe, reliable, and accepted by society, robust strategies for CO2 leakage detection, quantification and management are crucial. The STEMM-CCS (Strategies for Environmental Monitoring of Marine Carbon Capture and Storage) project aimed to provide techniques and understanding to enable and inform cost-effective monitoring of CCS sites in the marine environment. A controlled CO2 release experiment was carried out in the central North Sea, designed to mimic an unintended emission of CO2 from a subsurface CO2 storage site to the seafloor. A total of 675 kg of CO2 were released into the shallow sediments (∼3 m below seafloor), at flow rates between 6 and 143 kg/d. A combination of novel techniques, adapted versions of existing techniques, and well-proven standard techniques were used to detect, characterise and quantify gaseous and dissolved CO2 in the sediments and the overlying seawater. This paper provides an overview of this ambitious field experiment. We describe the preparatory work prior to the release experiment, the experimental layout and procedures, the methods tested, and summarise the main results and the lessons learnt.