Flow-rate controls on trapped hydrogen redistribution in a heterogeneous sandstone: a synchrotron X-ray micro-CT study
Year: 2026
Type: preprint
Abstract: Subsurface hydrogen storage in porous geological formations is a promising strategy for balancing temporal mismatches between renewable energy generation and demand. The viability of large-scale hydrogen storage depends on predicting hydrogen distribution, trapping, and recovery during cyclic injection and withdrawal operations. However, these multiphase flow processes are influenced by rock heterogeneity, capillary hysteresis and trapping at the pore-scale. In this work, fast in-situ synchrotron X-ray tomography was used to directly visualise hydrogen mobilisation during brine imbibition in a heterogeneous sandstone. By systematically varying the brine injection rate, the influence of flow conditions on hydrogen recovery, and the evolution of trapped hydrogen were quantified. Significant mobilisation of disconnected hydrogen clusters was observed during imbibition, even at low capillary numbers ($< 10^{-6}$). Rock heterogeneity influenced trapping behaviour, particularly during the early stages of imbibition. Our results highlight the importance of incorporating pore-scale heterogeneity and transient trapping mechanisms into hydrogen storage predictions.
Source: arXiv (Cornell University)
Language: English
Subfield: Environmental Engineering
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7216338150