Summary
A casual reading of the SPE/WPC (World Petroleum Congresses) Petroleum Reserves Definitions (1997) and the U.S. Securities and Exchange Commission(SEC) definitions (1978) would suggest very little, if any, difference in the quantities of proved hydrocarbon reserves estimated under those two classification systems. The differences in many circumstances for both volumetric and performance-based estimates may be small.
In 1999, the SEC began to increase its review process, seeking greater understanding and compliance with its oil and gas reserves reporting requirements. The agency's definitions had been promulgated in 1978 in connection with the Energy Policy and Conservation Act of 1975 and at a time when most publicly owned oil and gas companies and their reserves were located in the United States. Oil and gas prices were relatively stable, and virtually all natural gas was marketed through long-term contracts at fixed or determinable prices. Development drilling was subject to well-spacing regulations as established through field rules set by state agencies.
Reservoir-evaluation technology has advanced far beyond that used in 1978;production-sharing contracts were uncommon then, and probabilistic reserves assessment was not widely recognized or appreciated in the U.S. These changes in industry practice plus many other considerations have created problems in adapting the 1978 vintage definitions to the technical and commercial realities of the 21st century.
This paper presents several real-world examples of how the SEC engineering staff has updated its approach to reserves assessment as well as numerous remaining unresolved areas of concern. These remaining issues are important, can lead to significant differences in reported quantities and values, and may result in questions about the "full disclosure" obligations to the SEC.
Introduction
For virtually all oil and gas producers, their company assets are the hydrocarbon reserves that they own through various forms of mineral interests, licensing agreements, or other contracts and that produce revenues from production and sale. Reserves are almost always reported as static quantities as of a specific date and classified into one or more categories to describe the uncertainty and production status associated with each category. The economic value of these reserves is a direct function of how the quantities are to be produced and sold over the physical or contract lives of the properties.
Reserves owned by private and publicly owned companies are always assumed to be those quantities of oil and gas that can be produced and sold at a profit under assumed future prices and costs. Reserves under the control of state-owned or national oil companies may reflect quantities that exceed those deemed profitable under the commercial terms typically imposed on private or publicly owned companies.
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