Reservoir characterization of the Triassic Bunter Sandstone in the 43/28-NEPBH1 borehole: implications for CO ₂ storage in the neighbouring Endurance structure, Southern North Sea, UK

This study investigates the reservoir characteristics of the Triassic Bunter Sandstone Formation at the 43/28-NEPBH1 geotechnical borehole, contributing to the broader assessment of the Endurance structure for CO 2 storage. Utilizing an extensive core-based sedimentological and petrographical analysis, this paper identifies the reservoir quality and small-scale heterogeneities that may affect potential fluid flow within the Bunter Sandstone hydraulic unit. Located in the Silver Pit Basin, the borehole penetrates a complex sedimentological unit, deposited by fluvial, lacustrine and aeolian processes. The Bunter Sandstone exhibits a variety of depositional facies, including stacked sheetflood and channelized streamflood sequences interbedded with localized aeolian dune deposits and mudrocks. The findings of this paper reveal insights into the reservoir architecture of the Bunter Sandstone and, by detailing the spatial distribution of reservoir properties and heterogeneities, this research underscores the viability of the Bunter Sandstone as a candidate for effective geological CO 2 sequestration in the Southern North Sea region.