Deposition, Diagenesis And Porosity Of Birdbear Formation, Williston Basin, North Dakota
Bibliographic record
Abstract
The Birdbear Formation in Williston Basin of western North Dakota is a carbonate-evaporite sequence that has been the subject of much research over the past decades. This study looks at the depositional environment and the diagenetic characteristics of the formation, and their relation to production characteristics. Much has been done over the years on the Birdbear Formation, but most of these studies were restricted to eastern Montana (USA), southern Manitoba and south western Saskatchewan (Canadian province). The approach of integrating the role and effects of deposition, diagenesis, and porosity of the Birdbear Formation (Upper Devonian) Williston Basin in McKenzie County, North Dakota was the main purpose for this research. A detailed study was carried out through physical core descriptions, thin section analysis, wireline log correlations, and nuclear magnetic resonance (NMR) spectroscopy measurements to determine if the effects of diagenesis have been critical enough to alter or create adequate porosity and permeability within rock fabrics for the migration of generated hydrocarbons. Results from core analysis showed that two units were recognized, first being a lower carbonate dolomite-limestone of uniform lithology (boundstone to wackestone classification) with abundant organic material that could have served as self-sourcing in production and the second, an upper anhydrite-carbonate lithology (packstone classification), that has the ability to entrap migrating fluids within the study area. Sediments of the upper section of the lower carbonate unit exhibited high diagenetic activities that enhanced porosity and overall permeability through observed intra-crystalline, inter-granular, and moldic vuggy porosities that were confirmed by NMR analysis. These sediments also showed marked selective or partial dolomitization, micritization and dissolution of calcite cements from inclusion of brines that were effective in creating what could be excellent reservoir rock qualities in the potential for the Birdbear Formation as a hydrocarbon producer within the Williston Basin.
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 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".