Thermal maturity of Bowie coals in southern portion of Piceance Basin, Colorado

Conference · Wed May 01 04:00:00 EDT 1985 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:6170346

Merry, R D; Larsen, V E

The objective of this study was to investigate the physical factors that may have contributed to the high thermal maturity of the Piceance basin coals. Vitrinite reflectance (R/sub 0/), which increases with coal rank and provides a quantitative index of thermal maturity, was used to measure the thermal maturity of the coals. An examination of published R/sub 0/ data and R/sub 0/ analyses of coal samples from mines, outcrops, and well cuttings indicated that most of the thermal maturity of these coals is due to the thickness of overburden that covered the coals in Pliocene time. A plot of vitrinite reflectance versus reconstructed depth of burial during Pliocene time shows a reasonably good fit, however, some R/sub 0/ values are too high to be explained solely by depth of burial. A map of R/sub 0/ residuals was constructed using data obtained by subtracting predicted R/sub 0/ values from actual values. When compared with a geothermal gradient map, most of the positive R/sub 0/ residuals correlated with hot spots that were related to known igneous intrusives. Some anomalous hot spots may be related to unknown buried intrusives. A residual R/sub 0/ map, modified on the basis of the geothermal gradient map, was combined with preliminary R/sub 0/ map (based on reconstructed Pliocene depth of burial) to show that the resultant R/sub 0/ is due to depth of burial and geothermal hot spots. A final thermal maturity map was used to select areas in the Piceance basin that are most likely to contain thermally mature coals. The same procedure can be used to predict the thermal maturity of coals in other basins.

• Research Organization: CSM Research Institute, Golden, CO
• OSTI ID: 6170346
• Report Number(s): CONF-8506201-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 69:5
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
COAL DEPOSITS
COAL RANK
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
MACERALS
MATURATION
MINERAL RESOURCES
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PICEANCE CREEK BASIN
RESOURCES
SEDIMENTARY BASINS