Azimuthal AVO in Coal Beds, Western Canadian Basin: A Promising Method for Characterizing Fractures in Unconventional Gas Reservoirs
Bibliographic record
Abstract
Abstract Seismic analysis was conducted to predict the orientation of the dominant fracture (cleat) system in a Cretaceous coal bed gas reservoir within the unconventional Coal Bed Methane (CBM) play in central Alberta, Canada. The extension of the method of analyzing the variation of seismic amplitude as a function of offset (AVO) to include analysis of amplitude variation as a function of azimuth (azimuthal AVO) was utilized. This technique was applied to characterize seismic azimuthal anisotropy, which indirectly predicts fracture system orientations. The study focuses on identifying the azimuthal variation of the AVO response of the coal bed. By calculating three azimuthal AVO gradients from 2D multi-azimuth walkaway vertical seismic profiles (VSPs), the study revealed the existence of azimuthal anisotropy. A mathematical solution using these calculated AVO gradients defines the direction of the maximum change in amplitude with offset. This direction is always perpendicular to the orientation of the dominant fracture system. The reliability of the approach used in this study demonstrates a promising method for characterizing fractures in unconventional gas reservoirs.
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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 | 0.001 | 0.001 |
| 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) | 0.000 | 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".