--> ABSTRACT: Coaly Petroleum Systems in Laramide and Subandean Basins: Examples from the Washakie Basin Wyoming and Cauca Valley Basin, Colombia, by M. Garcia-Gonzalez and R. C. Surdam; #91021 (2010)

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Coaly Petroleum Systems in Laramide and Subandean Basins: Examples from the Washakie Basin Wyoming and Cauca Valley Basin, Colombia

GARCIA-GONZALEZ, MARIO and RONALD C. SURDAM

An integrated study of organic petrography and analyses was used to evaluate the oil generation potential of the Upper Cretaceous coals in the Greater Green River Basin of Wyoming. The results indicate that these coals have great potential to store large volumes of oil and gas. Under proper geological conditions (at a certain maturation level with appropriate microfracturing and faulting) a significant volume of these hydrocarbons both oil and gas, will be expelled from the coal beds, saturating the interbedded sandstone layers.

Hydrous pyrolysis experiments were used to simulate the generation and expulsion processes of Mesaverde coals and shales, and also to calculate their hydrocarbon generation potential. Hydrocarbon generation and destruction and the origin of some oil and gas fields in the Washakie Basin were modeled using the kinetic parameters obtained from these experiments.

The methodology developed in this study was also used to evaluate the hydrocarbon generation potential of coals in the Cauca Valley Basin of Colombia. The methodology proved to be very successful in areas where no subsurface samples were available. The Eocene-Oligocene coaly sequence of the Cauca Basin contains coals with hydrogen index values above 300 mg/g and excellent oil and gas generation potential. 

AAPG Search and Discovery Article #91021©1997 AAPG Annual Convention, Dallas, Texas.