North Sea prospects
To meet the UK’s target of achieving net-zero greenhouse gas emissions by 2050, we must upscale our CO2-storage capacity, and this requires the identification of suitable storage sites with robust geological seals. The North Sea has great potential as a CO2-storage hub for European industries, with around 70 Gt CO2-storage potential identified in the Norwegian sector alone. In the northern North Sea, the Utsira-Skade Aquifer looks particularly promising, especially as it is already used for CO2 storage in the southern North Sea at Sleipner. However, past estimates of its CO2-storage potential are inconsistent and range from 0.3 to 60 Gt.
Christopher Lloyd at the University of Manchester, UK, and colleagues use 3D broadband seismic reflection and well data to create a catalogue of CO2 storage prospects within the Skade, Eir and Utsira Formations, which make up the Utsira-Skade Aquifer, in the North Viking Graben, North Sea. The researchers identify prospective storage sites by defining the suitable storage region, calculating the porosity distribution, assessing the extent, geomorphology, thickness variability, and mudstone containment confidence, and mapping of closures through fill-to-spill simulations. Overall, the researchers identify 15 prospects, however, only five of these have a positive containment confidence score. These prospects have a combined storage capacity of 54 Mt CO2 if the full reservoir thickness is considered, or 39 Mt CO2 if considering the top-to-spill point of the closure. Four prospects are in the north-eastern part of the study area, near the Northern Lights exploitation license.
The containment confidence score assigned to any prospective storage site depends on the distribution and resolution of the available data, so may not account for unknown influences of faults, abandoned wells and seal integrity. Therefore, further localised analysis of the mudstone seal, as well as CO2 injection simulation will be required before the Utsira-Skade Aquifer can be further developed for CO2 storage.
• Earth Sci. Syst. Soc. 1 (2021); doi.org/10.3389/esss.2021.10041
Kyle Watts is a a PhD Research Fellow at the University of Stavanger, Norway, studying a field in the Barents Sea.