Abstract

This paper reports large data sets of vitrinite reflectance (R_m) and bottom hole temperatures (BHT) to illustrate the variable nature of the geothermal gradient and relates the gradient in selected locations to vitrinite reflectance in the Wind River Basin.

The Wind River Basin in central Wyoming is an asymmetrical structural and sedimentary basin formed during Laramide deformation in latest Cretaceous and early Tertiary time. Oil and gas production is from seventeen formations, primarily from structural traps. Keefer (1969) provides a detailed discussion of the geology of the basin with respect to petroleum generation.

The geothermal gradient is a simple parameter that correlates with organic material maturation and source material for hydrocarbons. Generalizations of thermal regime that lump almost the entire basin into one, or perhaps two, geothermal regimes exist, but a more finely tuned data set should provide greater precision in making determinations of viability for prospects on a more local, and less regional, scale. This, in turn, could improve the number of hydrocarbon discoveries.