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 basin’s carbon storage potential. The results of our analysis of the super basin’s 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 Copyright ©2023. The American Association of Petroleum Geologists. All rights reserved. Gold Open Access. This paper is published under the terms of the CC-BY license. Manuscript received July 26, 2022; provisional acceptance September 20, 2022; revised manuscript received March 13, 2023; final acceptance March 20, 2023. DOI:10.1306/04042322097 AAPG Bulletin, v. 107, no. 8 (August 2023), pp. 1419–1474 1419 AUTHORS J. R. Underhill ~ Interdisciplinary Centre for Energy Transition, School of Geosciences, University of Aberdeen, King’s College, Aberdeen, Scotland, United Kingdom; john.underhill@abdn.ac.uk John R. Underhill is the director of the Interdisciplinary Centre for Energy Transition and professor of geoscience and energy transition at Aberdeen University, Scotland. He is also the academic executive director of the Centers of Doctoral Training in Oil and Gas and in GeoNetZero and served as Heriot-Watt University’s chief scientist. He populates the Scottish Science Advisory Council and UK Subsurface Task Force. John is a recognized expert on the North Sea Basin and is leading efforts to repurpose it for carbon storage and the energy transition. He has been an AAPG member for almost 40 years, during which time he has received AAPG’s George C. Matson, Grover E. Murray Distinguished Educator, and Ziad Beydoun awards, as well as the Geological Society’s Lyell Medal and their Energy Group’s Silver Medal. He is the corresponding author of this paper. I. de Jonge-Anderson ~ Institute of GeoEnergy Engineering, School of Energy, Geoscience, Infrastructure, and Society, Heriot-Watt University (HWU), Edinburgh, Scotland, United Kingdom; I.Anderson@ hw.ac.uk Iain de Jonge-Anderson has a B.Sc. degree in petroleum geology from the University of Aberdeen (2011), an M.Sc. degree in petroleum geoscience from HWU (2013), and a Ph.D. in unconventional geomechanics (HWU, 2020). His research contribution to this paper was made whilst being a research associate evaluating carbon capture, utilization, and storage (CCUS) opportunities within the United Kingdom Southern North Sea. A. D. Hollinsworth ~ Institute of GeoEnergy Engineering, School of Energy, Geoscience, Infrastructure, and Society, HWU, Edinburgh, Scotland, United Kingdom; A.Hollinsworth@hw.ac.uk 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. INTRODUCTION AND AIMS Petroleum super basins are defined as those basins that have produced more than 5 billion BOE and hold additional recoverable reserves of 5 billion BOE or more (Sternbach, 2018, 2020). More than 40 super basins have been recognized globally, 10 of which contribute over three-quarters of the world’s total oil and gas production. With an increasing awareness of the need to pivot toward sustainable energy resources to meet global emission targets, there is more of a focus on super basins containing “advantaged resources” that can be decarbonized such that their indigenous reserves have a lower carbon footprint compared to oil and gas imports that would otherwise be needed, or areas that have the potential to be transformed for a low-carbon renewable energy future. Although not an energy source, carbon capture, utilization, and storage (CCUS) holds the potential by which emissions generated by power plants and heavy industrial sources may be sequestered and safely stored rather than being released into the atmosphere. In so doing, the possibility exists to ensure energy security is maintained and net zero emission targets achieved. The aim of this paper is to use play-based exploration (PBE) methods traditionally used in the subsurface interpretation of prospective petroleum basins to examine and test whether the AngloPolish Super Basin of northwestern continental Europe in general and the United Kingdom sector of the Southern North Sea in particular present a carbon storage opportunity. The results highlight the stratigraphic intervals and geographical areas that have the best potential for carbon storage as a means to meet net zero targets, transform the energy system, and extend the life of a petroleum super basin. THE ANGLO-POLISH SUPER BASIN Definition and Its Classification as a Petroleum Super Basin The Anglo-Polish Super Basin stretches from eastern England to central Poland, a distance of >900km and a width of >350km to Allan Hollinsworth has a B.Sc. degree in earth science (2015) and a Ph.D. in structural geology (2020), both obtained at the University of Glasgow. He undertook research relevant to this paper at HWU whilst undertaking a research project to evaluate CCUS opportunities within the United Kingdom Southern North Sea. He now holds a teaching fellowship at Bristol University. L. C. Fyfe ~ Institute of GeoEnergy Engineering, School of Energy, Geoscience, Infrastructure, and Society, HWU, Edinburgh, Scotland, United Kingdom; L.Fyfe@hw.ac.uk Laura-Jane Fyfe holds a B.Sc. in geology and an M.Sc. in integrated petroleum geoscience from the University of Aberdeen, where she also completed her Ph.D. in petroleum exploration of Scotland’s inshore west coast basins. As a postdoctoral research associate at the Institute of GeoEnergy Engineering, HWU, she has collaborated with energy companies and academia on research focussing on petroleum exploration and the energy transition.