Subsurface storage capacity in structural traps in underexplored sedimentary basins: hydrogen (H ₂ ) and carbon dioxide (CO ₂ ) storage on the Irish Atlantic margin

Abstract

Methodologies for storage assessment developed for basins with dense data coverage are typically not optimally applicable to underexplored sedimentary basins. To address this, a methodology and workflow for storage assessment in underexplored basins is presented which uses existing datasets to identify structural traps and populate a fluid-in-place equation which can be used for a variety of gases including CO 2 and H 2 . This is then applied to the Irish Atlantic margin; Jurassic, Triassic and Carboniferous reservoirs are investigated to understand their reservoir quality and extent, and related seals. Structural trap types are described and the theoretical capacities of three candidate sites with varying data coverage are calculated. The results highlight the potential for underexplored sedimentary basins on the Irish Atlantic margin to support offshore renewable energy projects and reduce Ireland's CO 2 emissions. This workflow is applicable to a variety of underexplored sedimentary basins and emphasises the utility of legacy hydrocarbon datasets for early-stage subsurface storage assessment. Other aspects of energy storage are also discussed, including man-made salt caverns, other candidate reservoir-seal pairs, and the potential for collaborative infrastructure development with CO 2 emitters and renewable energy projects.