12. Imaging Oil-Sands Reservoir Heterogeneities Using Wide-Angle Prestack Seismic Inversion
Bibliographic record
Abstract
Introduction Mass density, because of its linear relationship with porosity, has long been recognized as a potential seismic indicator of fluid saturation. Given its dependence on mineral composition, density can also be diagnostic for lithology. In this chapter, we discuss some key aspects of a wide-angle processing and density inversion workflow and apply it to a bitumen reservoir in Canada for imaging reservoir heterogeneities (e.g., shales) that can potentially act as permeability baffles. In this field, intrareservoir shales typically have higher densities than surrounding reservoir sands. This wide-angle workflow yields stable density estimates, from reflected P-waves alone, at a resolution suitable for mapping the intrareservoir shales. This study is based on data from the Surmont bitumen reservoir approximately 60 km southeast of Fort McMurray, Alberta, Canada, in the Lower Cretaceous McMurray formation. The oil is too deep (400 m) to mine. Steam-assisted gravity drainage (SAGD) technology is being used to inject steam into the reservoir and heat the oil so that it can be produced. Shale heterogeneities within the reservoir (Figure 1) thicker than 3 m could have an impact on steam chamber development and affect SAGD performance. Predicting the areal extent and the thickness of these bodies would lead to better reservoir management.
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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) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 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".