Unlocking the storage capacity of Paleogene sandstones in the Central North Sea

Meeting ambitious Net Zero targets will require the identification and de-risking of large saline aquifers for CO2 storage. With around 50% of the UK’s theoretical storage resource situated in the Central North Sea region, sandstones of Paleogene age are identified as a significant open aquifer storage concept. The system is characterized by a complex sequence of stacked and amalgamated fan sandstones. This study identifies some of the key challenges that will impact the future exploitation of the potential CO2 storage resource. Storage capacity estimates were first extracted from the UK’s online CO2 storage atlas, with the Mey and Forties sandstones identified amongst the units with the greatest potential. A substantial subsurface database was interpreted to identify and explore the key issues. The stacked and amalgamated nature of the sandstones leads to potential for lateral and vertical connectivity within and between different reservoir units. This can be potentially both a positive aspect in terms of multi-layered trapping potential and pressure dispersal, but also poses a challenge in terms of unwanted fluid migration. The study concludes that understanding pressure connectivity is a particularly important key to unlocking the CO2 storage capacity of the Paleogene saline aquifer systems of the Central North Sea.