Methane emissions from abandoned oil and gas wells: measurements and uncertainties
Bibliographic record
Abstract
Measurements have shown that abandoned oil and gas wells emit methane to the atmosphere, but the estimates of methane emissions at the national scales remain highly uncertain. Here, we provide an overview of available measurement data and studies investigating factors linked to high methane-emitting abandoned wells. We then analyze abandoned oil and gas well data in Canada and the United States to estimate methane emissions for both countries and evaluate uncertainties in the national estimates. Available measurement data indicate that average methane emission rates used as emission factors vary by 3 orders of magnitude or more, even after accounting for plugging status. Plugging status has been shown to be an important predictor of high methane emitting wells; however, there may be other important factors such as age, depth, fluid type and geographical region. Such well attribute data are not consistently available for many abandoned and orphaned oil and gas wells in Canada and the United States. Overall, there is a need for additional measurements of methane emissions from abandoned oil and gas wells and compilation of well attributes to reduce uncertainties in national estimates.
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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 | 0.004 | 0.009 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.006 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".