Basin-centered gas systems: gas resources
Basin-centered gas systems | |
Series | AAPG Bulletin, November 2002 |
---|---|
Author | Ben E. Law |
Link | Web page |
Globally, no resource data are available for basin-centered gas accumulations (BCGAs); however, where estimates of in place gas have been made the resources are very large: in-place gas resource estimates in the United States for a given BCGA are generally greater than 10 tcf (Table 1). Unfortunately, no comprehensive gas resource data exist for all BCGAs in the United States, in large part because BCGAs are not recognized as a distinct type of gas accumulation. However, an appreciation for the magnitude of the resource can be determined from estimates of in-place and recoverable gas in selected areas of the United States. Previous assessments of in-place gas in so-called tight and basin-centered accumulations in the United States are shown on Table 1. Using a volumetric methodology approach, in-place gas resources for the Piceance,[1] Greater Green River,[2] Wind River,[3] and Big Horn[4] basins in the Rocky Mountain region were estimated at 6788 tcf. In-place gas estimates in other basins range from 334 to 777 tcf (Table 1).
Basin | FPC 1973 | FERC 1978 | Kuuskraa et al. 1978 | NPC 1980 | ICF 1990 | USGS 1987, 1989 |
---|---|---|---|---|---|---|
Greater Green River | 240 | 240 | 91 | 136 | - | 5036 |
Uinta | 207 | 210 | 50 | 20 | - | - |
Pieance | 149 | 150 | 36 | 49 | 287 | 423 |
Wind River | - | - | 3 | 34 | - | 995 |
Big Horn | - | - | 24 | - | - | 334 |
Denver | - | - | 19 | 13 | - | - |
San Juan | - | 63 | 15 | 3 | 17 | - |
Ozona | - | - | - | 1 | - | - |
Sonora | - | - | 24 | 4 | - | - |
Edwards Lime | - | - | - | 14 | - | - |
Cotton Valley Sweet | - | - | 53 | 22 | 31 | - |
Cotton Valley Sour | - | - | 14 | - | - | - |
Ouachita | - | - | 5 | - | - | - |
Other | - | - | - | 481 | - | - |
TOTAL | 596 | 663 | 334 | 777 | 335 | 6788 |
FPC = Federal Power Commission (Supply-technical Advisory Task Force, 1973); FERC = Federal Energy Regulatory Commission (Supply-Technical Advisory Task Force, 1978); NPC = National Petroleum Council (1980); ICF = ICF-Lewan, Inc. (Haas, 1990); USGS = U.S. Geological Survey (Johnson et al., 1987, 1996, 1999; Law et al., 1989). All values in tcf gas.
There are even fewer published estimates of recoverable gas. In the United States, the National Petroleum Council (1992) estimated 232 tcf of recoverable gas from so-called tight reservoirs with current technology and 349 tcf of gas with advanced technology. In 1995, the U.S. Geological Survey (Gautier et al., 1996) included as part of their National Assessment several plays in seven basins that were determined to contain BCGAs. In that assessment, in-place gas resources were not estimated, and a methodology developed by Schmoker (1996) for estimation of recoverable gas was used. Estimates of recoverable gas from those basins are 223.55 tcf (Table 2). If all of the basins in the United States containing BCGAs would have been assessed, it is highly probable that the total recoverable gas in BCGAs in the United States would exceed 400 tcf.
Basin | USGS, 1996 | NPC, 1992 |
---|---|---|
Greater Green River | 119.3 | - |
Uinta-Piceance | 16.74 | - |
San Juan | 21.15 | - |
Denver | 3.16 | - |
Appalachian | 44.97 | - |
East Texas | 6.03 | - |
Columbia River | 12.2 | - |
TOTAL | 223.55 | 232 |
USGS = U.S. Geological Survey (Johnson et al., 1996); NPC = National Petroleum Council (1992). All values in tcf gas.
Production figures for the United States, like gas resource assessments, are uncertain; however, the estimate that most accurately reflects gas production from BCGAs in the United States is provided by the Gas Research Institute (GRI). Gas production from so-called tight gas sands in 1996 (the last year for which there are records) was 3.35 tcf (Hill, 2000), approximately 17% of total United States production. This figure, however, may be misleading because all so-called tight gas sands are not necessarily BCGAs; discrete, buoyancy-driven gas accumulations may occur in some tight gas sands. With this caveat under consideration, I estimate 15% of annual gas production in the United States is from BCGAs, the largest, gas-producing contributor of all unconventional gas accumulations.
References
- ↑ Johnson, R. C., R. A. Crovelli, C. W. Spencer, and R. F. Mast, 1987, An assessment of gas resources in low-permeability sandstones of the Upper Cretaceous Mesaverde Group, Piceance basin, Colorado: U.S. Geological Survey Open-File Report 87-357, 165 p.
- ↑ Law, B. E., C. W. Spencer, R. R. Charpentier, R. A. Crovelli, R. F. Mast, G. L. Dolton, and C. J. Wandrey, 1989, Estimates of gas resources in overpressured low-permeability Cretaceous and Tertiary sandstone reservoirs, Greater Green River basin, Wyoming, Colorado, and Utah: 40th Annual Field Conference, Wyoming Geological Association Guidebook, p. 39-61.
- ↑ Johnson, R. C., T. M. Finn, R. A. Crovelli, and R. H. Balay, 1996, An assessment of in-place gas resources in low-permeability Upper Cretaceous and lower Tertiary sandstone reservoirs, Wind River basin, Wyoming: U.S. Geological Survey Open-file Report 96-264, 67 p.
- ↑ Johnson, R. C., R. A. Crovelli, B. G. Lowell, and T. M. Finn, 1999, An assessment of in-place gas resources in the low-permeability basin-centered gas accumulation of the Big Horn basin, Wyoming and Montana: U.S. Geological Survey Open-file Report 99-315A, 123 p.
See also
- Basin-centered gas
- Basin-centered gas systems: historical development and classification
- Basin-centered gas systems
- Basin-centered gas systems: development
- Basin-centered gas systems: examples
- Basin-centered gas systems: gas resources
- Basin-centered gas systems: global distribution
- Basin-centered gas systems: evaluation and exploration strategies
- Tight gas reservoirs: evaluation