Application of vitrinite reflectance to interpret gas content, maximum depth of burial, and paleogeothermal gradient of coal beds in Dunkard basin

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

OSTI ID:5688311

Ulerly, J P; Puglio, D G

A thorough understanding of the interrelationship of the geologic history, thermal maturation, and petrographic characteristics of a coal bed is necessary to interpret its present methane content. Coalification of organic matter occurs contemporaneously with burial through the interaction of temperature and pressure during geologic time. The degree of coalification, referred to as rank or thermal maturity, is commonly measured by vitrinite reflectance. This value has been used by the Bureau of Mines to determine the rank of Permian and Pennsylvanian coal beds from several boreholes in southwestern Pennsylvania. From these values, estimates of former depths of burial and coalification temperatures may be made. Owing to the discontinuous nature of the Permian coal beds, detailed lithologic correlation of noncoal marker units was necessary to ensure that the coal bed reflectance values were placed in proper stratigraphic sequence. The thermal maturity, as indicated by vitrinite reflectance, was found to relate directly to by-product gas content. The average vitrinite reflectance gradient of all the bore holes is 0.10%/100 m (320 ft), which corresponds to gradients measured for the Rocky Mountain Foothills of Canada. An estimate of the paleogeothermal gradient for the study area, using the Karweil nomogram to appraise the paleotemperatures of the coal beds, indicates a significantly higher gradient than that proposed earlier. The former maximum depth of burial for these coal beds, based on the estimated paleogeothermal gradient, would be 1.2-1.5 km (0.7-0.9 mi).

• Research Organization: Bureau of Mines, Pittsburgh, PA
• OSTI ID: 5688311
• Report Number(s): CONF-8410269-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 68:12
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010600* -- Coal
Lignite
& Peat-- Properties & Composition
011000 -- Coal
Lignite
& Peat-- Reserves
Geology
& Exploration
ALKANES
BOREHOLES
CARBONACEOUS MATERIALS
CAVITIES
COAL
COAL DEPOSITS
COAL RANK
COALIFICATION
CORRELATIONS
ENERGY SOURCES
FEDERAL REGION III
FOSSIL FUELS
FUELS
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOLOGY
GEOTHERMAL GRADIENTS
HYDROCARBONS
MACERALS
MATERIALS
MATURATION
METHANE
MINERAL RESOURCES
NORTH AMERICA
OPTICAL PROPERTIES
ORGANIC COMPOUNDS
PALEOZOIC ERA
PENNSYLVANIA
PENNSYLVANIAN PERIOD
PERMIAN PERIOD
PETROGRAPHY
PHYSICAL PROPERTIES
REFLECTION
REFLECTIVITY
RESOURCES
SEDIMENTARY BASINS
STRATIGRAPHY
SURFACE PROPERTIES
TEMPERATURE EFFECTS
TEMPERATURE GRADIENTS
USA