Skip Links

USGS - science for a changing world

Open-File Report 03-325

Petroleum Source Potential of the Lower Cretaceous Mudstone Succession of the NPRA and Colville Delta Area, North Slope Alaska, Based on Sonic and Resistivity Logs

By Margaret A. Keller and Kenneth J. Bird

Thumbnail of and link to report PDF (28 MB)Abstract

Resource assessment of the North Slope of Alaska by the U. S. Geological Survey includes evaluation of the petroleum source potential of Mesozoic and Cenozoic rocks using the delta log R technique (Passey and others, 1990). Porosity and resistivity logs are used in combination with thermal maturity data to produce a continuous profile of total organic carbon content in weight % (TOC). From the pattern and amount of TOC in the profile produced, the depositional setting and thus the petroleum source-rock potential (kerogen type) of the organic matter can be inferred and compared to interpretations from other data such as Rock-Eval pyrolysis. TOC profiles determined by this technique for the contiguous interval of pebble shale unit, Hue Shale (including the Gamma Ray Zone or GRZ), and lower part of the Torok Formation indicate important potential for petroleum generation in the Tunalik 1, Inigok 1, N. Inigok 1, Kuyanak 1, Texaco Colville Delta 1, Nechelik 1, and Bergschrund 1 wells of the western North Slope region. TOC profiles suggest that this interval contains both type II and III kerogens – consistent with proposed depositional models -- and is predominantly greater than 2 wt. % TOC (cut-off used for effective source potential). Average TOC for the total effective section of the pebble shale unit + Hue Shale ranges from 2.6 to 4.1 wt % TOC (values predominantly 2-8% TOC) over 192-352 ft. Source potential for the lower Torok Formation, which also has interbedded sandstone and lean mudstone, is good to negligible in these 7 wells.

First posted September 12, 2003

For additional information, contact:
Energy Program contacts
U.S. Geological Survey
12201 Sunrise Valley Drive
National Center, MS 913
Reston, VA 20192

Part or all of this report is presented in Portable Document Format (PDF). For best results viewing and printing PDF documents, it is recommended that you download the documents to your computer and open them with Adobe Reader. PDF documents opened from your browser may not display or print as intended. Download the latest version of Adobe Reader, free of charge.


Suggested citation:

Keller, Margaret A., Bird, Kenneth J., 2003, Petroleum Source Potential of the Lower Cretaceous Mudstone Succession of the NPRA and Colville Delta Area, North Slope Alaska, Based on Sonic and Resistivity Logs: U. S. Geological Survey Open-File Report 03-325, http://pubs.usgs.gov/of/2003/0325/.


Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://pubsdata.usgs.gov/pubs/of/2003/0325/index.html
Page Contact Information: GS Pubs Web Contact
Page Last Modified: Monday, 07-Apr-2014 11:59:02 EDT