Pore-scale evaluation of hydrogen storage and recovery in basaltic formations
Bibliographic record
Abstract
Underground hydrogen storage (UHS) in basaltic rocks offers a scalable solution for large-scale sustainable energy needs, yet its efficiency is limited by poorly constrained pore-scale hysteresis during cyclic hydrogen-brine flow. While basaltic rocks have been extensively studied for carbon sequestration and critical mineral extraction, the pore-scale physics governing cyclic hydrogen-brine interactions, particularly the roles of snap-off, wettability, and hysteresis, remain inadequately understood. This knowledge gap hinders the development of predictive models and optimization strategies for UHS performance. This study presents a pore-scale investigations of cyclic hydrogen-brine flow in basaltic formations, combining micro-computed tomography imaging with pore network modelling. A systematic workflow is employed to evaluate the effects of repeated drainage-imbibition cycles on multiphase flow properties under varying wetting regimes, with emphasis on hysteresis evolution and its influence on recoverable hydrogen. Model validation is achieved through a novel benchmarking approach that incorporates synthetic fractures and morphological scaling, enabling calibration against experimental capillary pressure and relative permeability. Results show that hydrogen trapping is primarily governed by snap-off and pore-body isolation, particularly within large, angular pores exhibiting high aspect ratios and limited connectivity. Strong hysteresis is observed between drainage and imbibition, with hydrogen saturations averaging 85%, predominantly in larger pore spaces, compared to a residual saturation of 61% following imbibition. Repeated cycling leads to a gradual increase in residual saturation, which eventually stabilizes, indicating the onset of a hysteresis equilibrium state. Wettability emerges as a critical second-order control on displacement dynamics. Shifting from strongly to weakly water-wet conditions reduces capillary entry pressures, enhances brine re-invasion, and increases hydrogen recovery efficiency by ∼ 6%. These findings offer mechanistic insights into capillary trapping and wettability effects, providing a framework for optimizing UHS reactive and abundant, yet underutilized, basalt formations, and supporting ongoing global decarbonization efforts through reliable subsurface hydrogen storage. • Coupled quasi-static pore-network modelling with micro-CT imaging to simulate H 2 –brine flow in basalt pore networks. • Basaltic reserviors show potential for secure H 2 storage. • Snap-off and pore-body isolation govern hydrogen trapping in large pores with high aspect ratios. • Hysteresis equilibrium emerges after repeated drainage—imbibition cycles with residual H 2 saturation stabilizing by the fifth cycle. • Wettability alteration from a strongly to weakly water-wet regime reduces residual H 2 saturation from 0.60 to 0.55, boosting overall recovery efficiency by 6%.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".