Use of exploration methods to repurpose and extend the life of a super basin as a carbon storage hub for the energy transition

The Anglo-Polish Super Basin forms an important petroleum province that stretches across northwestern Europe. It contains many giant gas fields, primarily located beneath a thick upper Permian (Zechstein Group) evaporite canopy and a smaller amount of oil and gas in Mesozoic reservoirs in the suprasalt section. Although exploration activity continues in the super basin, discoveries have diminished in size; many fields have been decommissioned; and it is beginning a transformation from an area with a rich petroleum heritage to a new, low-carbon energy hub. Given its favorable geology, infrastructure, and the location of major industrial emitters in adjacent land areas, offshore parts of the super basin are being evaluated and repurposed for renewable technologies like wind and geothermal energy, and as possible sites for subsurface carbon dioxide, hydrogen, compressed air, and methane gas storage. The use of a rich, dense, and high-fidelity seismic, well log, core, and pressure data sets acquired during petroleum exploration and production activities provide the basis for a play-based exploration assessment of the super basins carbon storage potential. The results of our analysis of the super basins offshore waters of the United Kingdom sector suggest that storage in traps containing Carboniferous and Permian (presalt) and Triassic (postsalt) clastic reservoirs have the potential to extend the life of the mature super basin during the energy transition. The detailed evaluation of the Rotliegend Group, from which most of the gas in the basin has been derived, enables a prospective subsalt carbon storage reservoir play fairway to be defined, common risks to be identified, and composite maps to be produced that show where the best storage locations are situated. Similarly, mapping of depleted fields and dry closures created by salt mobility (halokinesis) that contain Triassic Bacton Group (Bunter Sandstone Formation) reservoirs provides the basis on which to build a carbon storage prospect and lead inventory in the suprasalt section. In addition to the geological criteria, our results highlight the need to be aware of nongeological risks including the integrity of the legacy well stock and colocation issues that arise from the competition for offshore areas, especially wind farms fixed to the sea bed, since these can constrain the areas available for carbon storage that lie below them.