Reservoir characterisation of the Flag Sandstone, Barrow Sub-basin, using an integrated, multi-parameter seismic AVO inversion technique
Bibliographic record
Abstract
The Early Cretaceous Flag Sandstone within the Barrow Sub-basin is a proven hydrocarbon reservoir. The main trapping mechanism is four-way dip closed anticlines, formed by drape compaction. An integrated, multi-parameter seismic AVO inversion technique was utilised that improved the mapping of the Flag Sandstone and identified the presence of trapped hydrocarbons.The identification of the Flag Sandstone on seismic sections is complicated due to a low acoustic impedance contrast between the Flag Sandstone and the overlying shales. The same interface gives a good AVO response. Previous interpretation efforts have used the seismic AVO response to map the top of the Flag Sandstone on far-angle stacks. These efforts were very successful for mapping structure but were influenced by wavelet tuning effects and were limited for high-grading the structures based on hydrocarbon potential. To aid in characterising the fluid distribution in the reservoir rocks a simultaneous AVO inversion algorithm was used based on three partial angle stacks and conditioned well logs, inverting for acoustic and shear impedance.The results of this multi-parameter impedance inversion produced a variety of attributes. The Vp/Vs attribute was aimed at improving the TWT structural pick whereas P-impedance became the basis for discriminating water and oil saturated sands.
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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 | 0.000 |
| 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) | 0.001 | 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".