Aquifer Controls on Coalbed Methane Development in the Powder River Basin, Wyoming
Bibliographic record
Abstract
Aquifer Controls on Coalbed Methane Development in the Powder River Basin, Wyoming P. R. Onsager; P. R. Onsager Questa Engineering Corporation Search for other works by this author on: This Site Google Scholar D. O. Cox D. O. Cox Questa Engineering Corporation Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Annual Technical Conference and Exhibition, Dallas, Texas, October 2000. Paper Number: SPE-63090-MS https://doi.org/10.2118/63090-MS Published: October 01 2000 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Onsager, P. R., and D. O. Cox. "Aquifer Controls on Coalbed Methane Development in the Powder River Basin, Wyoming." Paper presented at the SPE Annual Technical Conference and Exhibition, Dallas, Texas, October 2000. doi: https://doi.org/10.2118/63090-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Annual Technical Conference and Exhibition Search Advanced Search Abstract Development of coalbed methane (CBM) in the Wyodak-Anderson seams of the Powder River Basin, Wyoming, is one of the most active plays in the world. Compared to other CBM producing basins, the Powder River Basin subbituminous coal has relatively low gas content (20–50 scf/ton), but high permeability (100s of millidarcy to 1+ darcy). Because of the shallow depth, Powder River Basin CBM development is normally on 40- or 80-acre well spacing. Another significant difference between the Powder River Basin and other producing CBM basins is the fact that the coal seams of the Powder River Basin are overlain and underlain by large, thick aquifers that are essentially infinite-acting in nature. The degree of hydraulic connection between these aquifers and the coal is a critical factor in the economics of gas production from this play. Where the aquifers are well connected to the coal, water influx or leakance is high, leading to a nearly steady-state pressure environment that will deter efforts to dewater the coal and produce methane. Using reservoir simulation analyses and actual field data on gas and water production, this paper examines the effect of aquifer leakance on the producibility of the coal. Optimum well spacing in the Powder River Basin is shown to depend on having sufficient wells per section to lift the water that leaks into the coal from the aquifers. In fact, in some parts of the basin, aquifer leakance will maintain reservoir pressure high enough that it will curtail methane desorption and restrict ultimate gas recovery. Further testing and analysis to better characterize the aquifers and their connection to the coal is necessary. Keywords: production rate, upstream oil & gas, permeability, complex reservoir, spe 63090, recovery efficiency, efficiency, coal seam gas, coalbed methane, production profile Subjects: Well & Reservoir Surveillance and Monitoring, Unconventional and Complex Reservoirs, Coal seam gas Copyright 2000, Society of Petroleum Engineers You can access this article if you purchase or spend a download.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 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) | 0.000 | 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 teacher head, 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".