Scattering effect on shallow gas-obscured zone imaging in Bohai PL19-3 area
Bibliographic record
Abstract
ABSTRACT Seismic imaging is challenging in the Bohai Bay PL19-3 area, offshore China. Bohai Bay Field is seismically obscured, making well penetrations the only reliable source of data for subsurface interpretation. With the help of turning-ray tomography, we are able to obtain a reliable near-surface velocity model approximately down to 700 m below sea level, using the first arrivals picked from streamer data. Depth migration using velocities estimated from turning-ray tomography has improved shallow structures and fault definition. However, reservoir level structures from 800 to 1500 m are still poorly imaged. A viscoelastic modeling study with assigned variable Q and shallow velocity profiles, with and without shallow gas-induced scatterers, demonstrates that scattering is the primary controlling phenomenon causing imaging difficulty within the obscured zone. Due to scattering, imaging tests at the target level were unsuccessful even with precise knowledge of velocity.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 0.001 |
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 teacher head, 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".