Thermal conductivity analysis of Cenozoic, Mesozoic and Paleozoic core samples, Beaufort-Mackenzie Basin, northern Canada
Bibliographic record
Abstract
One hundred and sixty-two vertically-oriented (parallel to core axis and direction of heat flow), one-inch (2.54 cm) diameter core plugs were obtained from conventional cores from 43 petroleum exploration wells in the Beaufort-Mackenzie Basin. Samples were collected from Upper Cretaceous-Oligocene post-rift and Jurassic-Lower Cretaceous syn-rift sandstone and shale, and Paleozoic pre-rift sandstone, shale and carbonate. Multiple disk samples (approximately one cm in thickness) were cut from these plugs and used for thermal conductivity analysis. Samples were measured dry and saturated with heptane (three samples were water-saturated) using the steadystate divided-bar apparatus at the Geological Survey of Canada in Calgary. In general, each disk sample was measured in triplicate by two different analysts and results were averaged for each set of replicate disk samples to yield 136 dry, 129 heptane-saturated and three water-saturated bulk conductivity values for samples from 39 wells (some samples disintegrated during preparation and analysis). Sample porosity values for the first analyst (initial measurements) are systematically higher than those for the second analyst. A comparison of dry and saturated density data suggests that residual heptane saturation (from incomplete oven drying) has resulted in higher dry density values and lower porosity values for the second analyst and therefore the values of the first analyst are considered to represent the true porosity. Rock matrix thermal conductivity values were calculated for each sample using six different conductivity models: series, parallel, Sugawara and Yoshizawa, self-consistent effective medium theory, Maxwell/Hashin-Shtrikman and weighted geometric mean. The weighted geometric mean model provides the most consistent fit to the thermal conductivity data for all lithologies and for the full range of porosity values (0 to 25 %). Average geometric mean rock matrix values for dry and heptane-saturated thermal conductivity measurements generally agree to within 0.1 W/mK or better for sandstone, shale and carbonate samples from different age/tectonic groupings. Post-rift lithic sandstone and pre-rift sandstone samples are relatively homogeneous with average rock matrix thermal conductivity values of 2.5 W/mK and 3.1 W/mK, respectively. The syn-rift sandstone samples are more heterogeneous with matrix conductivity values ranging from approximately 2.2- 3.5 W/mK. The lowest matrix conductivity (0.8 W/mK) was determined for organic-rich, post-rift shale samples from the Smoking Hills sequence. Organically-lean post-rift and syn-rift shale samples have similar matrix conductivity values of 1.65 W/mK and 1.6 W/mK, respectively, whereas pre-rift shale samples have a higher average matrix value (2.1 W/mK). The average matrix conductivity for pre-rift carbonate samples is approximately 2.6 W/mK with dolomite samples having a higher average matrix conductivity (2.7 W/mK) than the limestone samples (2.5 W/mK). Water-saturated bulk thermal conductivity (Kwater) values were calculated using the geometric mean matrix conductivity values in order to estimate in situ thermal conductivity for the various rock successions examined. Post-rift sandstone and shale samples have Kwater values ranging from 1.3- 2.5 W/mK and 0.7-2.1 W/mK, respectively. Kwater values range from 1.5-3.4 W/mK and 1.0-2.3 W/mK for syn-rift sandstone and shale samples, respectively. For the pre-rift succession, Kwater values range from 2.1-3.4 W/mK for sandstone, 1.7-2.3 W/mK for shale and 2.0-3.2 W/mK for carbonate samples.
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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 | 0.003 | 0.003 |
| Science and technology studies | 0.002 | 0.001 |
| 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".