Volume of organic-rich Devonian shale in the Appalachian basin: relating black to organic-matter content
Some estimates of natural-gas resources in the Devonian shale of the Appalachian basin depend on the volume of organic-rich shale in the basin. A map by L.G. Wallace and W. de Witt showing the thickness and extent of Devonian black shale facies in the Appalachian basin is widely used as an indicator of organic-rich shale, but the map is derived from subjective evaluations of shale color. Wallace and de Witt's definition of black is shown here to correspond to an organic-matter content of approximately 4% or more by volume and a Munsell color value for dry pressed-powder samples of about N5 (medium gray) or darker. The volume of Devonian shale with an organic-matter content greater than 2.0% by volume (a definition of organic-rich that is preferred by the writers) averages 1.44 times that of the black shale of Wallace and de Witt, and totals about 2574 x 10/sup 12/cu ft (72.9 x 10/sup 12/ cu m) in the Appalachian basin.
- Research Organization:
- Geological Survey, Denver, CO
- OSTI ID:
- 5594583
- Journal Information:
- Am. Assoc. Pet. Geol., Bull.; (United States), Vol. 66:3
- Country of Publication:
- United States
- Language:
- English
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APPALACHIAN MOUNTAINS
NATURAL GAS DEPOSITS
BLACK SHALES
RESOURCE ASSESSMENT
NATURAL GAS
RESERVES
DEVONIAN PERIOD
SEDIMENTARY BASINS
SOURCE ROCKS
BITUMINOUS MATERIALS
CARBONACEOUS MATERIALS
CHATTANOOGA FORMATION
ENERGY SOURCES
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC STRUCTURES
MATERIALS
MINERAL RESOURCES
MOUNTAINS
OIL SHALES
PALEOZOIC ERA
RESOURCES
ROCKS
030200* - Natural Gas- Reserves
Geology
& Exploration