Effects of single vertical fluid-filled fractures on full waveform dipole sonic logs
Bibliographic record
Abstract
Abstract We conducted a parametric study of the effects of single, finite-width, adjacent, vertical, fluid-filled fractures on full-wave borehole dipole logs using the transformed boundary integral equation method. We found that a fracture has significant effects on dipole response if it is within half the wavelength, or two to three times the borehole diameter, from the borehole center. Dual flexural waves and a leaky fracture mode resulted from the waveguide composed of the borehole and fracture. The first flexural wave was controlled by both the borehole and fracture, whereas the second flexural wave was controlled primarily by the borehole but influenced by the fracture. The separation of these two flexural waves increased and the strength of the first one decreased when the distance between the fracture and the borehole increased. The leaky fracture mode was represented by a sharp minimum in the amplitude spectrum, and energy leakage to the fracture reached a maximum when the fracture intersected the borehole. These two unique characteristics distinguish a single fracture from anisotropy. We also estimated location, orientation, and aperture of the fracture through waveform and spectral analyses.
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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 | 0.004 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.001 |
| 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".