Production of methane from hydrate deposits beneath the Nankai Trough
Bibliographic record
Abstract
The U.S. Geological Survey (USGS) has estimated there is upwards of 100,000 trillion cubic feet (Tcf) of global methanehydrate resources, worldwide (Collett, 2011). The Japan Oil Gas and Metals National Corporation (JOGMEC) has been actively evaluating the potential of developing methane hydrate marine sediments as a resource. There have been trials in onshore Canada in 2007 and 2008; and, there are plans to test offshore production in the next few years. Existing plans involve two well tests in the eastern Nankai Trough, offshore Japan. An initial short-term well test of up to one month will be followed by an extended well test of up to six months. The production method trialled in Canada and planned for the offshore well tests is depressurisation. This involves drilling from the surface (or seabed) to a subsurface methane hydrate zone and reducing the formation pressure to a point where the methane hydrates dissociate to methane and water. The gas and water are then transferred to the surface, the water is treated for disposal and the gas is treated for exportation. Recent research was done to confirm the technical feasibility of the planned offshore well tests. This research examined:production mechanism and flow assurance;production host functional specification;subsea equipment including flowlines, production riser and electro-hydraulic umbilical;topsides well test equipment; and,procurement and installation methodology. The main conclusion made was confirmation of the technical feasibility of the proposed offshore well test. The key challenges, uncertainties and areas for future focus in the lead up to the proposed offshore well tests were also highlighted.
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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 | 0.001 |
| 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) | 0.001 | 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".