Characteristics of gas accumulation in a less efficient tight-gas reservoir, He 8 interval, Sulige gas field, Ordos Basin, China
Bibliographic record
Abstract
Abstract Because of the lack of gas supply from source rocks and gas loss, inefficient tight-gas fields represent a high share of all gas reservoirs in China. These gas fields are characterized by low abundance and large gas reserves. Here, the He 8 tight-gas reservoirs in the western region of the Sulige gas field are used as an example to characterize gas distribution under conditions of less efficient charging. Results show the following characteristics. First, the sandstone densification process has a relatively large impact on the charging of gas. Litharenite was already subjected to densification at the time of large-scale gas charging, and this was not conducive to gas charging. On the contrary, for sublitharenite, although strong compaction has already occurred during gas generation, quartz overgrowth that leads to further densification of the gas reservoirs occurs simultaneously with large-scale gas charging. This facilitates gas charging and is characterized by concomitant densification and reservoir formation. Second, structure traps can control the accumulation of gas to a certain extent. In particular, when physical properties of sandstones within the structure traps are appropriate, gas saturation during gas charging can be increased by approximately 7%. Third, less efficient charging is the main cause of the complex gas and water distribution in the He 8 gas reservoirs. The strong heterogeneity of the reservoirs and the decline in the gas reservoir pressure caused by tectonic uplift in the Yanshan period further exacerbate the complexity of gas and water distribution. These factors ultimately caused the He 8 gas reservoirs to become a multireservoir gas field with several gas–water interfaces. The He 8 gas reservoirs are neither conventional gas nor continuous gas reservoirs. Rather, they are quasi-continuous gas reservoirs, and the accumulation of gas is controlled by both the top surface of sandstone and the physical properties of the reservoirs. Traps and high-quality reservoirs within the regional traps are beneficial for the gas accumulation.
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 | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 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".