Multicycle Injection and Withdrawal in Sedimentary Basins, a Multi-Disciplinary Analysis of Pore-Scale Fluid Flow for Hydrogen Storage

Hydrogen (H2) is viewed worldwide as one of the key pathways to reducing GHG emissions, especially in hard to abate sectors. However, the beneficial implementation of hydrogen as a fuel for transport, and in industries such as steel production requires a constant, reliable supply of hydrogen independent of the availability of energy. Therefore, hydrogen storage will be needed on a range of time scales, and over a range of volumes. Geological storage in porous reservoirs offer the largest storage ‘containers’, with volumes large enough to cover even seasonal cycles. However, this also means that H2 storage will be cyclic, and this cyclical nature in combination with the variable timeframes of that storage introduce complexity into the system at multiple scales. Effective and efficient operation of H2 storage sites thus requires understanding of how both injection rate itself, and how cyclical injection/ withdrawal cycles will impact fluid (e.g., H2-formation water, H2-buffer gas) interactions in the reservoir. To further develop this understanding, we utilise analogue and numerical modelling in addition to petrographical analysis to identify potential areas of further research within this underexplored topic.