Reservoir characterization and facies prediction within the Late Cretaceous Doe Creek Member, Valhalla field, west-central Alberta, Canada
Bibliographic record
Abstract
Abstract Oil resources at Valhalla field of west-central Alberta, Canada, are stratigraphically trapped within the Upper Cretaceous Doe Creek Member of the Kaskapau Formation. The reservoir is subdivided into four thin (1–10 m [3–33 ft]), cyclic alternations of offshore mudrock and shoreface sandstone that are designated the I − 1, I, I + 1, and I + 2 units. The thickest and most widespread I sandstone is the primary reservoir. Optimum reservoir quality corresponds to coarser grain shoreface sandstone; however, reservoir quality may be diminished by postdepositional calcite cement commonly observed near the top of shoreface sandstones. Open-hole well logs are used to predict depositional facies and calcite cement occurrence in wells that lack core control. Decreasing shale volume (Vsh) and increasing deep resistivity values correspond to progressively shallower water deposits. Zones of calcite-cemented shoreface sandstone greater than 0.5 m (1.6 ft) thick are interpreted when the neutron porosity exceeds the density porosity by more than 7%. Facies distributions predicted for the I sandstone closely match trends of the sandstone gross pore volume and daily total fluid production, and suggest that open-hole well logs may be used to anticipate reservoir quality and continuity. Regional and local observations support previous interpretations that attribute the Doe Creek to forebulge erosion and southwestward sediment transport toward a foredeep where shoreface sandstones accumulated within a coastal embayment to the Western Interior seaway. Regionally, the Doe Creek interval thins northeast of Valhalla and is truncated beneath the K1 unconformity, and shoreface sandstone bodies are encased within offshore mudrocks and detached from their contemporaneous shoreline. Locally at Valhalla, the Doe Creek reservoir progrades toward the southwest and is extensively and commonly uniformly burrowed by a relatively diverse assemblage of trace makers.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 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".