New Plays in an Old Field: Depositional History and Source Rock Characterization at Teapot Dome, Wyoming

Abstract

University of Louisiana at Lafayette

Logan Adams

Teapot Dome oilfield near the town of Midwest, Wyoming has been the testing

site of numerous drilling and production techniques since the early 1900’s. The structure

is a doubly plunging basement-cored anticline that formed during the Laramide orogeny,

with sediments ranging from Cambrian to Quaternary. The Steele, Niobrara, and Mowry

formations are potential source rocks in the area. In this study, we combine geochemical,

numerical, and well-log analysis to evaluate the potential of the field for unconventional

exploration. Rock Eval pyrolysis and oxidation of shale samples produced preliminary

results showing a mixture of type II and type III kerogen in the Niobrara and Mowry

formations, while the Steele formation had no potential for hydrocarbon generation.

These geochemical results, combined with regional tectonics, stratigraphy, and paleo

conditions, were implemented into burial history and maturation models. Results from

the modeling show that the Niobrara and Mowry formations are in the early oil

generation window, with the Mowry generating a considerably larger amount of

hydrocarbons. Finally, a detailed well log analysis is undertaken using various methods to

determine TOC content in areas where core analysis is not available. Passey, Issler, and

Schmoker are three different log analysis methods that will be tested in order to provide

an accurate correlation between Rock Eval TOC and log derived TOC. The results and

method of this study can easily be extrapolated to better constrain the basin evolution of

nearby fields. This study is significant for further exploration in other established

Laramide basins with similar formations.