Minimum Horizontal Stress Profile From Logging Data for Montney Formation of North East British Columbia
Bibliographic record
Abstract
Abstract Microfrac or fall off injection test is a technique used to accurately measure minimum horizontal stress directly in the formation. However, other than being expensive and time consuming, this test does not give a continuous minimum horizontal stress profile. Continuous minimum horizontal stress profile is especially important for hydraulic fracturing design for the tight Montney formation. This study utilizes logging data and core reports to generate the minimum horizontal stress profile for two Montney wells in North East British Columbia. Specific value of tectonic stress determined from injection fall off analysis is also included in the calculation. The first method, conventional method, calculates minimum horizontal stress by solving linear poroelasticity equations with vertical stress equal to the overburden. Closure pressure from fall-off injection test is used as a calibration point to acquire tectonic stress. The second method incorporates the tectonic, thermal effect and rock mechanical properties at each incremental depth to generate the minimum horizontal stress. The third method, vertical transverse isotropy (VTI), is conducted assuming different rock properties on the vertical and horizontal direction and also different tectonic strain for the maximum and minimum direction. The conventional method yields the lowest minimum horizontal stress magnitude without any distinctive characteristic. On several zones, the VTI method shows higher stress magnitude above Montney and reveals some good zone containment for hydraulic fracturing design, which the conventional method does not provide. From the injection fall off analysis, a second closure pressure with lower value than the first closure is believed to represent the overburden stress. It is concluded that this area has a thrust fault regime in which overburden stress is the least principle stress.
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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 | 0.002 |
| 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) | 0.002 | 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".