Whole rock geochemical analysis of a low accommodation fluvial reservoir: an example from the (Lower Cretaceous)
Bibliographic record
Abstract
Whole rock geochemical analysis of ninety core samples from the Basal Quartz (BQ) in six wells from southern Alberta has allowed the concentrations of 47 elements to be determined for each sample. These data are used to geochemically define three component units of the BQ, namely the Horsefly, the BAT and the Ellerslie. The results demonstrate that the technique of chemostratigraphy (or chemical stratigraphy) can be used to clearly differentiate these units. The BQ in southern Alberta is a prolific hydrocarbon reservoir comprising a complex sequence of sandstones and silty claystones. Due to its low accommodation, fluvio-estuarine setting, robust interwell correlation of the component units is required to fully exploit the reservoir. Previously, detailed petrographic study of the coarse grained components has been used to aid with regional mapping of the reservoir. The petrographic work allows definition of two cycles within the BQ and three component units of the upper cycle (the Horsefly, BAT and Ellerslie). Once defined, the distribution of these reservoir sandstones can be regionally mapped. Chemostratigraphy, using whole rock geochemical data, is a method that enables characterisation and correlation of the fine-grained component of the BQ. The geochemical data obtained for this paper demonstrate that the silty claystones from the Horsefly, the BAT and the Ellerslie each have sufficiently distinctive elemental compositions to allow their differentiation. The key elements used for this differentiation, such as Al2O3 ,N a2O, K2O, P2O5, Rb, Zr, Cr and Nb, are related to changes in detrital clay and heavy mineralogy.
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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 | 0.001 |
| Science and technology studies | 0.001 | 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".