Estimation of fast and slow shear wave velocities from P-wave data: A Montney case study
Bibliographic record
Abstract
Summary Optimization of hydraulic fracture treatments in tight gas reservoirs requires an in-depth understanding of the reservoir conditions. Elastic properties estimated with standard isotropic amplitude variation with offset (AVO) inversions can offer insight into areas that may be more susceptible to brittle deformation, but do not provide information regarding natural fracture networks or differential stress fields in the rock mass. A more complete characterization therefore requires estimates of anisotropy to account for these phenomena. Azimuthal AVO inversion makes use of changes in reflection amplitudes with angle and azimuth to extract estimates of anisotropic parameters from seismic data. This case study of the Lower Triassic Montney Formation in NE British Columbia, Canada, showcases an anisotropic extension to the isotropic AVO inversion to include estimates of the fast and slow shear wave velocities. The corresponding ratio of fast and slow shear wave velocities then provides an indication of anisotropy, from which inferences can be made regarding the presence of natural fractures or differential stress fields within the reservoir.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 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".