Coal beds: source rock and reservoir

Conference · Sun Apr 01 04:00:00 EST 1984 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:6383986

Rightmire, C T

Coal beds are known to exist in parts of almost all major sedimentary basins in the conterminous US from outcrop to depths in excess of 15,000 ft (4570 m). Coal-bearing strata often exist interbedded with tight gas reservoirs, making it very difficult to differentiate the tight gas resource from the methane-from-coal beds resources. Studies of the methane-from coal beds resource have determined that it may exceed 400 tcf. Measurements of methane in coal beds have shown that much gas generated during coalification is not currently present in the coal beds and may have escaped into stratigraphically contiguous formation which are not tight gas reservoirs. Bituminous coals have been analyzed that contain more than 600 ft/sup 3/ of methane per ton of coal, or approximately 1 mmcf of gas per acre-foot of coal. More than 5000 ft/sup 3/ is generated during the thermochemical alteration of peat to the low volatile bituminous-semi-anthracite boundary. Only a fifth to a third of that gas appears to be retained in the coal. The excess gas may be a source for other reservoirs. Analysis of coal samples collected throughout the US shows gas contents ranging from less than 25 ft/sup 3//ton for subbituminous coals in the Powder River and San Juan basins to more than 500 ft/sup 3//ton for coals in parts of the Green River, Raton, San Juan, and Appalachian basins. In the Powder River basin, where the coal resource is very large, even the low gas content coals have potential as producing gas reservoirs.

• Research Organization: TRW Inc., McLean, VA
• OSTI ID: 6383986
• Report Number(s): CONF-8405216-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 68:4
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
011000 -- Coal
Lignite
& Peat-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200* -- Natural Gas-- Reserves
Geology
& Exploration
ALKANES
BITUMINOUS COAL
BLACK COAL
CARBONACEOUS MATERIALS
COAL
COAL DEPOSITS
COALIFICATION
ENERGY SOURCES
FOSSIL FUELS
FUELS
GEOLOGIC DEPOSITS
HYDROCARBONS
MATERIALS
METHANE
MINERAL RESOURCES
NATURAL GAS DEPOSITS
ORGANIC COMPOUNDS
ORIGIN
RESERVOIR ROCK
RESOURCES
ROCKS
SEDIMENTARY ROCKS
SOURCE ROCKS
SUBBITUMINOUS COAL