Ryder Scott



Job Title

Don P. Roesle - Chairman and Chief Executive Officer


BS degree, petroleum engineering, University of Texas, 1971
MS degree, petroleum engineering, University of Texas, 1973
Industry Sponsored Short Courses in Pressure Transient Analysis and Well Log Evaluation


Tau Beta Pi, Pi Epsilon Tau

Professional Associations

Registered Professional Engineer in the State of Texas
Member, Society of Petroleum Engineers
Member, Society of Petroleum Evaluation Engineers
Member, Industry Advisory Committee to the Department of Petroleum and Geosystems Engineering at the University of Texas
Member, Engineering Advisory Board of the College of Engineering at the University of Texas

Area of Expertise

Over thirty-five years of experience in the oil and gas industry, mainly in reservoir engineering.  Have been involved in numerous projects over the years requiring the application of technical analysis in both engineering and geological disciplines.  Have served as the lead engineer for several of Ryder Scott's major clients and developed multi-discipline asset teams to accomplish major reservoir evaluation projects.

Reservoir Engineering:  Broad experience in traditional reservoir engineering applications such as decline curve analysis, volumetrics, log analysis, well test analysis, material balance, pressure transient analysis, PVT analysis, and other reservoir engineering applications.  Have applied these techniques in a broad range of engineering assignments to gain a high proficiency with standard reservoir engineering tools.  Have analyzed reservoirs producing under primary, secondary and tertiary recovery mechanisms.  As a result of this background, can determine the best method to apply to achieve a solution to both routine and complex reservoir problems.

Integrated Reservoir Studies:  Have worked extensively with geologists and geophysicists on projects requiring the consolidation of interpretations of all types of data into an integrated answer that fully describes the best solution to a reservoir evaluation.  Through these projects have developed a working knowledge of geological and geophysical concepts to allow for a better understanding of the techniques required for the most accurate reservoir characterization coupled with reservoir engineering applications that will lead to a complete integrated reservoir study that incorporates the input from both the engineering and geological disciplines.

Economic Evaluations:  Have completed many oil and gas economic evaluations for use in several different types of financial applications.  Bank loan requirements, SEC filings, acquisition and divestiture transactions, estate tax requirements, initial public offerings, internal company financial planning and various other projects have relied on these economic evaluations as a basis for financial decisions. Have developed these economic evaluations using both in-house cashflow software developed by Ryder Scott and commercial programs more widely used in the industry.

Reserve Certifications:  Work with the SEC and WPC/SPE reserve definitions on a daily basis and therefore have developed a strong familiarity with the application of these definitions in the classification of reserves. Have also dealt with the reserve definitions set by other exchange commissions such as those in Canada, Hong Kong and London. Have had numerous dealings with the U. S. Securities and Exchange Commission on behalf of Ryder Scott clients.

Acquisition and Divestiture Work:  Have conducted numerous reservoir evaluation studies for use in both acquisitions and divestitures of oil and gas properties for many of Ryder Scott's clients including the United States Department of Energy, Apache Corporation, Louis Dreyfus Natural Gas, and Union Pacific Resources.  Have been involved in all aspects of data room procedures both setting up data rooms for the presentation of work performed by Ryder Scott for divestitures of client properties and have visited many data rooms to gather data for potential acquisition studies for clients.  Fully understand the concept of short deadlines and highly confidential work involved in most data room related projects. Aware of the business and financial aspects of both acquisitions and divestitures and the importance of the due diligence process.

Initial Public Offerings:  Have been involved in several initial public offerings (IPO) of clients and understand the need for complete documentation and disclosure of work in these types of situations which come under intense public scrutiny by regulatory agencies and the financial community. Have assisted clients with both the reserves evaluation and financial aspects of initial public offerings.


Reservoir engineering experience in the following areas:

United States

Anadarko Basin
Arkoma Basin
Midland Basin
Los Angeles Basin
Gulf Coast Basin
Black Warrior Basin
Appalachian Basin
Offshore Gulf of Mexico
Michigan Basin
Williston Basin
Big Horn Basin
Powder River Basin
Delaware Basin
Green River Basin
Denver Basin


South America


Depositions in numerous lawsuits
Hearings before the Securities and Exchange Commission
Advisory role to the Department of Energy
Ontario Superior Court of Justice

Summary of Employment

Ryder Scott Co. LP    1975 to Present
Joined Ryder Scott Company as a reservoir engineer in 1975.  Elected as a Vice President in 1979.  Elected Senior Vice President in 1995 and became a Director in 1997.  Elected Executive Vice President in 1997, President and Chief Operating Officer in 2000, Chief Executive Officer in 2005.  During the entire period 1975 to date, conducted and supervised reservoir engineers and geologists in ongoing evaluation studies for numerous clients.  Reservoir studies have included but are not limited to a determination of oil, gas, condensate and plant product reserves for oil and gas property appraisals, analysis of waterflood and pressure maintenance projects, enhanced oil recovery projects, infill development drilling projects, and acquisition projects.  Clients have included independent and major oil and gas producers ( both domestic and international ), pipeline companies, utilities, banks, insurance companies, governmental agencies, investors, and law firms. Current role as Chief Executive Officer involves oversight of all day to day operations of the company from both an engineering and business aspect.

Tenneco Oil Co.    1973 to 1975
Area Reservoir Engineer for the Houston, Corpus Christi and South Texas Districts.  Production engineering and drilling engineering assignments in Texas, Louisiana and Alabama. Primary responsibilities included workover and recompletion proposals, development drilling proposals and complete field studies. Worked with company production engineers to optimize field operations and maximize field production rates.