Operational overview of the first offshore production test of methane hydrates in the Eastern Nankai Trough
Bibliographic record
Abstract
Abstract In March 2013, the world's first field trial of gas production from marine methane hydrate deposits was conducted in the Daini Atsumi Knoll area of the Eastern Nankai Trough off the Pacific coast of Japan as a process to bring gas hydrates under seafloor to valuable energy resource. The technique used to dissociate the ice-like material was "depressurization method" that had been applied in the previous production test in Mallik site, the Northwest Territories, Canada in 2007-2008. Japan Oil, Gas and Metals National Corporation (JOGMEC) as a part of MH21, the Research Consortium for Methane Hydrate Resources in Japan planed and supervised the project with the funding of the Ministry of Economy, Trade and Industry (METI), and scientific supports from the National Institute of Advance Industrial Science and Technology (AIST). One production well with two monitoring boreholes were drilled in the test site for the test. Along with the flow test operation, intensive data acquisition program was planned and implemented to understand behavior of methane hydrate dissociation- bearing sediments against depressurization. To realize high degree of drawdown in relatively shallow formation below deepwater, several downhole devices were designed and installed. The flow test started in the morning of March 12 and lasted until severe sand production forced to terminate the operation six days later. During the stable production term, gas flow rate was approximately 20,000m3 under atmospheric condition, and gas liquid ratio was larger than 100. A lot of data including formation temperatures, fluid pressure and temperature, and physical property changes in the formation were obtained. The data taken are under studies to verify applicability of the depressurization technique as a methane hydrate production technologies.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".