Geological evaluation of suprasalt carbon storage opportunities in the Silverpit Basin, United Kingdom Southern North Sea

Geological CO₂ storage presents an opportunity for industrial innovation and revitalization by offsetting greenhouse gas emissions. Its deployment can help countries meet national “net zero” targets and address the multifaceted challenges of the climate crisis. Being a well-studied, data-rich, mature basin facing major industrial clusters located in northeastern England, the United Kingdom Southern North Sea has the potential to be a significant geological CO₂ storage location. Numerous well-defined, periclinal and domal closures that host Lower Triassic Bunter Sandstone Formation reservoirs, sealed by Middle Triassic mudstones and evaporites, are prime storage targets. We present a critical geological evaluation of the Bunter Sandstone Formation closures in the Silverpit Basin of the Southern North Sea, based on closure depth, container size, and seal integrity. Integration of seismic well ties, the seismic interpretation of key stratigraphic horizons and their depth conversion using a seven-layer velocity model provides the basis for a new theoretical CO₂ storage capacity model that incorporates volumetric calculations and CO₂ phase and density based on depth and well-calibrated temperature data. The results enable the carbon storage potential of 11 closures to be risked, compared, and ranked. Three large (>1200 million tons of CO₂ [MtCO₂]) and six modest (8-300 MtCO₂) Bunter Sandstone-bearing dry closures and two depleted gas fields have been identified, forming a geological CO₂ storage portfolio for the Silverpit Basin. A further three closures were discounted due to shallow crestal depths and geological (fault-related) integrity concerns. This initial ranking process paves the way for site-specific studies that incorporate geological heterogeneity and nontechnical risks to geological CO₂ storage, including well integrity concerns.