Thermal maturation by vitrinite reflectance of Woodford Shale, Anadarko Basin, Oklahoma

Journal Article · Fri Nov 01 04:00:00 EST 1985 · AAPG Bull. (See CODEN: AAPGB); (United States)

OSTI ID:6141825

Cardott, B J; Lambert, M W

The Woodford Shale (Upper Devonian-Lower Mississippian), a black shale widely regarded as an important hydrocarbon source rock, has attained thermal maturity to postmaturity with respect to the generation of liquid hydrocarbons in most of the Anadarko basin in western Oklahoma. Untreated whole-rock well cuttings and core material from selected 10-ft intervals of the Woodford Shale in 28 wells were examined under reflected white light. Thermal maturation was determined by measuring the reflectance in oil immersion (R /SUB o/ ) of first-generation vitrinite particles. A minimum of 45 reflectance measurements were recorded for each well representing one or more sample intervals. The Woodford Shale was sampled at depths from 5,060 ft (1,542 m) in the northeastern shelf to 25,115 ft (7,655 m) in the deepest part of the basin. A systematic increase in mean vitrinite reflectance (mean R /SUB o/ ) with depth was observed over much of the Anadarko basin. From northeast to southwest across the basin, mean R /SUB o/ increases from 0.48 to 2.61%. High temperatures have raised the Woodford Shale to anthracite rank in two wells (4.29 and 4.89% R /SUB o/ ) in the deep Anadarko basin. An isoreflectance map for the Woodford Shale indicates those areas of the basin where the thermal history of the shale is optimum for preserving liquid hydrocarbons (mean R /SUB o/ of 0.5 to 2.0%). Computer-generated plots of vitrinite reflectance versus depth provide a regression equation that predicts the vitrinite reflectance of the Woodford Shale at any depth in the Anadarko basin and determines the amount of erosion.

• Research Organization: Oklahoma Geological Survey, University of Oklahoma, Norman, OK
• OSTI ID: 6141825
• Journal Information: AAPG Bull. (See CODEN: AAPGB); (United States), Journal Name: AAPG Bull. (See CODEN: AAPGB); (United States) Vol. 69:11; ISSN AABUD
• Country of Publication: United States
• Language: English

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04 OIL SHALES AND TAR SANDS
040100 -- Oil Shales & Tar Sands-- Reserves & Exploration-- (-1989)
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ANTHRACITE
BITUMINOUS MATERIALS
BLACK COAL
BLACK SHALES
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CHATTANOOGA FORMATION
COAL
COMPUTER GRAPHICS
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FEDERAL REGION VI
FOSSIL FUELS
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MATURATION
MEASURING METHODS
MINERAL RESOURCES
NORTH AMERICA
OIL SHALE DEPOSITS
OIL SHALES
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OPTICAL PROPERTIES
PHYSICAL PROPERTIES
REFLECTIVITY
REGRESSION ANALYSIS
RESOURCES
SOURCE ROCKS
STATISTICS
SURFACE PROPERTIES
THERMOGRAPHY
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WELLS