Hydrocarbon Gas Composition and Origin of Gas Hydrate from the Alaska North Slope
Bibliographic record
Abstract
Abstract Hydrocarbon gas composition and isotopic composition of methane were analyzed from cutting samples obtained from industry oil wells penetrating the Eileen and Tarn gas-hydrate deposits. These gas-hydrate deposits overlie the Prudhoe Bay and Kuparuk River oil fields and are restricted to the updip part of a series of nearshore deltaic sandstone reservoirs in the lower Tertiary (Eocene) Mikkelsen Tongue of the Canning Formation and the Tertiary Staines Tongue of the Sagavanirktok Formation, respectively. The Eileen and Tarn gas hydrates are thought to contain a mixture of deep-source thermogenic gas and shallow, microbial gas (methane carbon isotopic composition ranges from —54 to —46% in the gas-hydrate zone). Thermogenic gases likely come either from existing oil and gas accumulations or from source rocks within the oil- and gas-generating window that have migrated updip and or upfault and formed gas hydrate. The timing of gas source mixing is unknown. The microbial gases likely have a source contribution from biodegraded oil or gas in the underlying oil fields, as evidenced by the carbon isotopic composition of methane, ethane, propane, and carbon dioxide. The distribution of the Eileen and Tarn gas-hydrate accumulations appears to be controlled in part by the presence of large-scale regional faults that may have acted as vertical and lateral gas migration conduits.
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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 | 0.000 |
| Science and technology studies | 0.000 | 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".