Publication Date


Document Type


First Advisor

Carpenter, Philip J.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Earth, Atmosphere and Environment


The Powder River Basin, located in Wyoming, is a moderate producer of hydrocarbons with production hovering around 100 million barrels of oil per year. Recently the Niobrara Formation has garnered attention for hydrocarbon exploration and production using both conventional and unconventional drilling. A quick-look method for evaluating organic content, using either existing or real time data sets gathered from geophysical well logs, provides an opportunity to rapidly, accurately, and economically assess the formation’s organic content and thus hydrocarbon bearing potential. The popular Schmoker method determines organic content by relating gamma ray intensity to formation density. It has been successfully employed in Devonian Appalachian Basin Shales and the Bakken Formation of the Williston Basin to determine total organic content. This study seeks to expand application of the Schmoker method to the Cretaceous Niobrara Shale of the Powder River Basin. Using publicly available geophysical well log data from the Wyoming Oil and Gas Conservation Commission for the Wyoming Niobrara Formation 26 wells were identified in the southern part of the basin, each of which displayed two distinct intervals: the first an organic interval containing gamma ray intensities of greater than 100 API and density less than 2.65 g/〖cm〗^3 and the second a non-organic interval containing gamma ray intensities of less than 100 API and density greater than 2.65 g/〖cm〗^3 . Total organic content ranges from 0-6.31%, with 70% of the wells showing economically viable total organic content over 2%. The analysis shows economically viable total organic contents occur throughout the middle of the study area.


97 pages




Northern Illinois University

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