Enhanced imaging with high-resolution full-waveform inversion and reverse time migration: A North Sea OBC case study
Bibliographic record
Abstract
Abstract In a case study from the Tommeliten Alpha area of the Norwegian North Sea, imaging problems were caused by the presence of gas in the overburden. In particular, a large part of the reservoir is in a seismically obscured area (SOA) caused by the gas. Full-waveform inversion (FWI) and reverse time migration (RTM) dramatically improve the imaging from ocean-bottom cable (OBC) acquisition over the region. The FWI algorithm is pushed to 22 Hz to generate an extremely high-resolution velocity model, and RTM then becomes required to honor the complexity in the resultant velocity model. Consequently, migration is done with the FWI model to generate a high-frequency RTM image to 80 Hz. This image is approximately double the maximum frequency commonly used for RTM in the North Sea and matches that of equivalent Kirchhoff products, but with all the benefits in imaging that RTM brings, providing a subsequent impact on interpretation of the area.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 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".