Permeability of Salt-Rock Samples: Insights into Hydrogen Transport
Bibliographic record
Abstract
Abstract This study explored hydrogen permeability in four salt-rock samples from the Lotsberg Salt Formation and its caprock using a modified pressure pulse decay (PPD) system. Experiments were conducted under a constant confining pressure of 28.6 MPa, with hydrogen pressures ranging from 1 MPa to 7 MPa. Our findings show that for anhydrite and marlstone samples, permeability measurements correlated with the reciprocal average pressure due to the Klinkenberg effect, which was corrected to determine intrinsic permeabilities of 7.22 × 10−22 m² for S1, 9.21 × 10−21 m² for S3, and 2.31 × 10−21 m² for S4. The sample from Ernestina caprock, primarily composed of 95% anhydrite with minor dolomite, shows lowest permeability. However, halite salt rock S2 exhibited deviations from the expected linear relationship at lower pressures, indicating enhancing slip and Knudsen flow effects due to its smaller pore sizes. This sample's behavior highlights the influence of nano-scale structural characteristics on flow phenomena, necessitating advanced flow model for analysis. By integrating the correction of transition flow into our analysis for S2, the intrinsic permeability is determined to be 17.3 × 10−21m2.
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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".