Wyoming State Geological Survey
Ronald C. Surdam
Director/State Geologist
Wyoming State Geological Survey
P.O. Box 1347
Laramie, WY 82073



Contact Information

Robert Waggener
Editor in Chief
307-766-2286, ext. 255

News Release June 8, 2010

New WSGS publication could help Rocky Mountain natural gas exploration

A new Wyoming State Geological Survey (WSGS) publication could help the oil and gas industry with natural gas exploration and development in Wyoming and other Rocky Mountain states.

The WSGS utilized a technique called “spectral decomposition” to map reservoir rocks in and around the Stagecoach Draw Field, located on the Sandy Bend Arch, approximately 25 miles northwest of Rock Springs. The arch is within the Green River Basin – one of the major natural gas producers in North America.

“Spectral decomposition, which breaks down seismic signals into their various frequencies, enhances the ability to map thin beds in the tight gas sands of the Rocky Mountains,” said the report’s primary author, Yuri Ganshin, a project geologist with the WSGS. The term tight gas sand refers to a low-permeability sandstone reservoir that produces natural gas.

Ganshin used spectral decomposition to reprocess seismic data from a subsurface area of approximately 70 square miles within the Stagecoach Draw Field. WesternGeco, a business unit of Schlumberger, provided the seismic data, but the interpretation of the data is that of the WSGS.

Ganshin said results from the study are important for continued development and expansion of the field, in part because the WSGS detected and mapped gas-saturated reservoir rocks within the 30-well area of current development. The report suggests similar gas-saturated rocks may exist southeast of the Stagecoach Draw Field.

The study also determined the western limit, or wedge, of the upper Almond marine sandstones – the targeted producing formation at Stagecoach Draw Field. The wedge is where the formation thins and then terminates.

The publication should be of interest to the oil and gas industry, energy consultants, geoscience students and faculty members, geologists and those interested in the geology of Wyoming.

The title of WSGS Report of Investigations No. 59 (RI 59) is “Mapping an Almond bar wedge at Stagecoach Draw Field, southwestern Wyoming: Application of spectral decomposition technique.”

Co-authors are WSGS geologist Scott Quillinan and WSGS Director and State Geologist Ronald Surdam.

The 28-page report includes 14 illustrations, including seismic attribute sections and maps showing the gas-bearing Almond Formation. Copies are $7 each, plus shipping fees and applicable taxes.

To order, visit the WSGS Online Store at http://sales.wsgs.uwyo.edu/catalog/index.php.

Customers can also examine and purchase RI 59 and other publications and maps at the WSGS on the University of Wyoming campus, or they can order them by calling the sales office at 307-766-2286, ext. 224, or e-mailing wsgs.sales@wyo.gov.

The mission of the WSGS is to promote the beneficial and environmentally sound use of Wyoming’s vast geologic, mineral and energy resources while helping protect the public from geologic hazards. By providing accurate information and expanding knowledge through the application of geologic principles, the WSGS contributes to economic growth and improvement in the quality of life for Wyoming’s residents.