Permeability of Breccia Facies in the Athabasca Oil Sands
Bibliographic record
Abstract
Abstract Breccia is a lithological facies present in the McMurray Formation of the Athabasca oil sands of northeast Alberta. It consists of mud or shale clasts embedded in clean sands. The mud content of this facies varies from 0-100% and the clasts range in size from millimetres to metres with varying degree of angularity and sorting. Breccia is common in bitumen reservoirs. From an in-situ recovery perspective, breccia can alter fluid flow and reduce the overall oil saturation due to the presence of the mud clasts. To properly characterize the reservoir flow properties, it is necessary to develop a systematic procedure to assign the vertical and horizontal permeability of breccia zones on a scale that is suitable for the numerical simulation of recovery methods such as steam-assisted gravity drainage (SAGD). A methodology to calculate the 2-D permeability of breccia facies from core photographs and mathematical theory has been described in a previous paper. However, core photographs do not capture the three dimensional nature of the mud clasts in the breccia. In this paper, the 2-D theory is extended to 3-D by treating the mud clasts as impermeable ellipsoids. The effective permeability of breccia regions may be calculated from the permeability of the sand in which the mud clasts are embedded if the size and orientations of the clasts are known. As for the 2-D case, the results from theory are in satisfactory agreement with those from flow simulation. Using the theory specialized to the case of oblate spheroidal clasts, a procedure is developed to estimate the 3-D permeability of breccia regions, based on 2-D information from core photographs. The paper concludes with guidelines for systematic permeability assignment in the breccia zones of the oil sands as well as other similar formations.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 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".