The Bells Corner borehole geophysical calibration facility of the Geological Survey of Canada
Bibliographic record
Abstract
Calibration sites provide important opportunities for the standardization of downhole instrument response. Using quantitative physical properties from borehole cores, calibration adds value to projects by allowing for data consistency from hole-to-hole, system-to-system, and importantly, over time. The Geological Survey of Canada (GSC) maintains the Bells Corners Calibration Facilities near Ottawa, Canada, which is available to all members of the geophysical logging community. In the late 1970's and early 1980's, the GSC developed quantitative borehole calibration facilities, consisting of model calibration boreholes for gamma-ray spectral logging probes with known concentrations of potassium (K), uranium (U), and thorium (Th), density calibration blocks for gamma-gamma tools, and six deep boreholes in Palaeozoic sedimentary (sandstone, dolomite, shale) and Precambrian (granitic) bedrock. The deep boreholes were continuously cored, range in depth from 120 - 300 m, and are sited within a 10 to 100 m triangular configuration for cross-hole capabilities. The published downhole log suite includes spectral gamma-ray, density, neutron, induced polarization (IP), self potential (SP), resistivity, acoustic velocity, magnetic susceptibility, and fluid temperature. In recent years, new GSC calibration datasets have been collected in these wells including high-resolution televiewer imaging, acoustic velocities, and high-resolution temperature and fluid conductivity. An effort is underway to update downhole and petrophysical core measurements, maintain standardization for traditional downhole instruments, and conduct demonstration projects with newly developed downhole instruments so that sites remain relevant to members of the groundwater, geotechnical, and extractive sectors.
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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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.003 | 0.007 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.029 | 0.006 |
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".