Laboratory Ultrasonic Measurements on Cambrian Sands: Implications for Seismic Monitoring in Deep CO2 Sequestration Projects
Bibliographic record
Abstract
ABSTRACT: Basal Cambrian sandstones lie directly above the crystalline craton in many of the basins of North America. Their depth and petrophysical characteristics make these formations prime zones for long term geological sequestration of CO2 Active source seismic monitoring to track evolution of CO2 plumes will generally be required. Full use of the seismic data, however, requires knowledge of how the seismic responses change with saturation state and effective stress. We have recently completed P and S wave velocity measurements on a suite of Cambrian sandstone cores from the Deadwood Formation in the Williston Basin, Saskatchewan. This contribution focuses on the experimental techniques developed to make measurements. Samples were subject to confining pressures up to 60 MPa, and pore fluid pressures up to 17 MPa under both inert N2 and distilled water saturations. P wave velocities at the highest confining pressures are largely insensitive to saturation state. In contrast, S-wave velocities show significant variation highlighting the influence of bulk saturated density. This difference between P- and S-wave behavior may need to be considered during development of seismic monitoring strategies.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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".