Management Team

William L. Coleman, President, has been managing Zavanna’s growth and strategic direction since its formation in 1994.  In 1981, Bill founded Prairie Petroleum, Inc. (“Prairie”), to market oil and gas prospects in the Williston and Powder River Basins.  Prairie was the foundation for Zavanna.

Bill received his B.A. in Economics from Duke University in 1973 and his M.B.A. from Tulane University in 1978.  He began his career as a landman with Atlantic Richfield in 1975 working in its Denver, Dallas and Midland offices.  In 1979, he moved to Aminol USA in Houston to work the offshore Gulf Coast and moved on to become a Division Land Manager for the Rocky Mountains.

Bill has published two articles for The Landman;

• Coleman, W.L. (November/December 1996). Oil and Gas Exploration and the Environment: Working Together, a Blueprint for the Future. The Landman, Volume 41 (6), Pages 55-60.
• Coleman, W.L. (March 1978).  Economic Analysis.  The Landman, Volume XX111 (1), Pages 40-44.

Jerrold N. Mayer, Senior Vice President of Exploration and Production, joined the Zavanna team in 1996.  He received his B.S. from North Dakota State University in 1976.  In 1979, he received his Masters from Utah State University.  Jerry began his career with Texaco as a Geologist in 1979.  In 1981, he moved to Cotton Petroleum as a Geologist to generate prospects throughout the Rockies, concentrating on the Williston Basin.  In 1986, he started as a Geologist with Apache Corporation and was promoted to Rocky Mountain Region Exploration Manager in 1989. 

Carole J. Slinkard, Chief Financial Officer, has been with Zavanna since its formation in August 1994.  She received her B.S. in Marketing from Southern Illinois University in 1976.  In 1985, she earned her Accounting Degree from Metropolitan State College of Denver and passed the C.P.A. exam in November 1985.  She held the Controller position at numerous companies in manufacturing before becoming involved in the oil and gas industry in 1992.  Carole brings extensive financial experience in the oil and gas industry and oversees all financial aspects of the company.

Kathrine L. Weissner, Accounting and Land Manager, has worked for Zavanna for over five years.  She graduated Magna Cum Laude from the University of Colorado at Boulder.  Prior to joining Zavanna in 2005, Kathrine worked as an accountant.

Gordon T. Vaskey, Vice President of Geoscience, began his association with Zavanna in 2007.  He received his B.A. in Geology from the University of Montana in 1980, and his M.S. in Geology from the University of Oregon in 1982.  Gordon started his career in 1982 with Gulf Oil in Casper, WY, working the Williston and other Rocky Mountain basins.  Following the Gulf/Chevron merger, he continued to work for Chevron in both Denver and Houston as a geologist/geophysicist.  In 1999, he left to join PYR Energy in Denver, where he was the Exploration Manager until the company was acquired in a merger in 2007.  Gordon has spent the majority of his career developing exploration prospects throughout the Rockies, California, Nevada, and Alaska.

Robert C. Eller, Vice President of Operations, joined Zavanna in 2010. Robert received his B.S. in petroleum Engineering from Texas Tech University in 1983. His 28 years of oil and gas industry experience has included a Field Engineer position with Halliburton Energy Services in the Mid-Continent region, a Completions Engineer for Trans-Texas Gas Corporation in the Texas Gulf Coast and South Texas region, and a Production Engineer for J-W Operating Company where he was responsible for production operations in the Rockies and in the Appalachians.

Dr. C. Mark Pearson, Vice-President of Well Completions for Zavanna (aka “Chief FracDog”). Mark's responsibilities cover all aspects of well performance post-drilling of Zavanna's wells.  He is an SPE Distinguished Member who has over 30 years of experience and is a well known industry expert in the field of well completion and stimulation technology. Mark has published over 30 technical papers and received a number of industry accolades for the economic impacts of his work.