Resource Evaluation Program

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History of the Bureau of Ocean Energy Management National Assessment

The Department of the Interior (DOI) has completed eight comprehensive OCS resource assessments since 1976 (Table of Historic Assessments). These National Assessments are the results of multiyear efforts by geoscientists, engineers , economists, and mathematicians working together in order to assess the undiscovered crude oil and natural gas resources of the Nation’s OCS areas.

Although multiple assessments exist, there is not a sound basis for comparing those assessments due to changes in methodology over time and fundamental changes in the underlying data. Over the years the geological and geophysical (G&G) information available to government assessors has increased dramatically. This increase in the availability of data has allowed BOEM to expand considerably its knowledge regarding the resource potential of the OCS. The biggest volumes of these data have been confined predominantly to the Central and Western Gulf of Mexico and Southern California.

Early resource assessments focused on reporting estimates of undiscovered economically recoverable resources (UERR). But oil and natural gas prices have experienced considerable volatility since these initial assessments were completed. As a result, assessments reporting (UERR) typically utilized different prices and sets of economic conditions. The frequency of developing new resource estimates could not keep pace with changes in oil and gas prices. Beginning in 1995 BOEM began primarily on reporting estimates of undiscovered technically recoverable resources (UTRR). In an attempt to present a more complete picture of the total hydrocarbon endowment, some assessment reports have also included estimates of cumulative production, reserves, and reserves appreciation.

UTRR refer to quantities of hydrocarbon resources expected to be present in undiscovered pools within a play using technology and exploration and development efficiency available or reasonably foreseeable at the time of the assessment. No explicit consideration for economic viability is implied in the estimation UTRR resources. The estimates of undiscovered technically recoverable resources are presented as a range of values corresponding to different probabilities of occurrence. Photo of drill ship with platform


UERR are the portion of undiscovered technically recoverable resources that can be explored, developed, and commercially produced at given cost and price considerations using present or reasonably foreseeable technology. The estimates of economically recoverable resources are presented as a range of resource values corresponding to different resource prices.

The period covered by the assessments is one in which the oil and gas industry’s technology capabilities expanded immensely. Today the oil and gas industry possesses the ability to drill exploratory wells in water depths exceeding 10,000 feet and to exploit discoveries in over 7,500 feet. The use of three-dimensional (3-D) and other advanced seismic data and interpretation techniques has served as a catalyst to transform the geosciences and the petroleum industry. Resource assessment techniques also became more sophisticated during the same period. Therefore, over the time frame of these assessments, the magnitude of resources believed to be technically recoverable continues to grow dramatically with each assessment.

Resources and Publications

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