Formation model and special significance of helium-rich coalbed methane reservoirs in Mu’ai Block, Junlian
Bibliographic record
Abstract
The Junlian Mu’ai core area of Sichuan province is the first successfully commercialized Coalbed Methane (CBM) field in southern China, which has leading significance in the development of CBM in southern China. However, its rich geological reason remains to be further revealed. Based on the data from a large number of CBM evaluation test wells, CBM test wells and CBM development wells in the study area, combined with testing and assaying analysis, referring to and borrowing from oil and gas research results, and combining with the geological background, the unique CBM enrichment and formation mode has been analyzed. The research shows that the average CBM of the main coal seams in Junlian Mu’ai core area is 15.58 m3/t, which is characterized by “medium high ash coal, high CBM content and high saturation”, and the helium is abnormal, with an average content of 0.074%. The CBM enrichment area is mainly located at the Mu’ai fault side of the syncline axis of Tiechanggou and the western and southern edges of the block. The helium anomaly area and the CBM enrichment area have synergy. The high salinity of groundwater in this area is its distinctive feature. The average TDS is 10 638.3 mg/L, which is far higher than the TDS value of domestic and foreign shallow CBM production areas. And it also has the characteristics of “high chloride ions, high sulfate ions”. This is closely related to its location at the edge of Sichuan Basin, weak tectonic activity, and the formation water is mudstone compaction drainage water mixed with atmospheric precipitation. The area with high salinity has high CBM content, helium anomaly, and overpressure phenomenon. It is speculated that the helium anomaly mainly comes from the degassing of water-soluble helium in deep centrifugal flow. Therefore, a new model of CBM reservoirs is proposed, that is, the structure-mixed hydrodynamic sealing helium-rich CBM accumulation model. The structure mainly reflects two aspects: one is that the reverse fault with good sealing provides a beneficial boundary for helium-rich CBM enrichment; the other is that the structural trace controls the reservoir, including the low part of the wide and gentle syncline axis and the high part of the structure. The mixed hydrodynamic force is reflected in the comprehensive control of mudstone compaction centrifugal flow and atmospheric precipitation centripetal flow in the unique sedimentary basin, which contributes to the formation of helium-rich CBM reservoirs. As a result, the water-CBM and helium gas in the original gas reservoir have synergism, and this dynamic synergism is still consistent in the later drainage and production process. Therefore, the enrichment of helium in CBM reservoirs may be an important indicator for the CBM enrichment.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 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".