This report summarizes, at the petroleum basin level, the United States Geological Survey's World Energy Program 1993 assessment of world conventional oil and gas resources. The maps provided show boundaries of petroleum basins that are referenced by the assessment, as well as, future oil and gas potential. The 'Futures' or future potential of a basin is calculated as the the sum of the Identified Reserves and the modal value assigned to the conventional Undiscovered Resources.

Although program tests have been made, no guarantee (expressed or implied) is

This article describes the first public presentation, by basin, of quantitative, worldwide conventional petroleum and natural gas resource assessments. These assessments are presented in tabular form along with a world petroleum basin map keyed to the tables. The assessments are now available on a US Geological Survey web site, http://energy.er.usgs.gov/products/papers/world{_}oil/index.htm. On the web site, the USGS offers vector digital presentation of the basins and other world geographic outlines. Each basin is numbered and keyed to a table showing basin number, basin name, and resource estimates including: Cumulative Production, Identified Reserves, and Undiscovered Resources of both oil and gas.

Estimating the amounts of oil and gas that will be produced from known fields beyond proved reserves was an important part of the 1987 assessment of U.S. oil and gas potential. These resources, inferred reserves, are comparable in magnitude to proved reserves. Their estimation was based upon the only nationwide series of successive estimates of proved reserves of fields grouped by year of discovery. Although that data series ended in 1979, it documented a pattern of field growth that could be extrapolated for known fields. The estimated inferred reserves for the lower 48 states were 16 billion bbl of crude oil and 96 tcf of natural gas.

How much oil and gas remains to be discovered in the United States is an important question for petroleum geologists. This paper presents an overview of the methods used by the U.S. Geological Survey in its assessment by play of undiscovered resources of the onshore and state offshore areas of the United States. For the 1989 assessment, new estimation procedures were designed to aid the geologist in the assessment of the size distribution for the remaining population of undiscovered accumulations. This paper presents the details of that procedure and examples of its application for two oil plays in Wyoming and Montana: the Minnelusa play in the Powder River basin and the Basin- Margin Anticline play in the Bighorn basin.In the new procedure, a truncated shifted Pareto (TSP) distribution was fitted to the size data for the discovered accumulations, which were generally split into three sequential parts: the first, second, and last one-third of the accumulations discovered in each play. Parameters from the fitted curves describing size and shape of the discovered accumulations provided a reference model for use in estimating the size distribution of the undiscovered accumulations in a play. In a given play, these accumulation size distributions multiplied by the estimated distribution for the numbers of undiscovered accumulations produced the resource estimates. This method provides a simple, straightforward, and flexible means for the geologist to use statistics as an aid in estimating undiscovered resources.

In recent years, the US Geological Survey (USGS) has classified oil and gas resources as a function of geologic certainty and economic feasibility. Amounts of undiscovered resources have been estimated using a variety of techniques, each of which has strengths and weaknesses. Almost all techniques rely on the two basic concepts of analogy and exhaustion (historical information). Although no method, short of drilling, is certain in its determination of undiscovered resources, several reasonable methods are possible, including volumetric- or areal-yield models and historical-performance models. Other basic methods include discovery process and finding-rate models, which are essentially specialized types of historical performance models, and deposit-simulation and reservoir-performance models, which use basic petroleum engineering equations to make predictions. Mass-balance models are designed to predict oil and gas volumes on the basis of geologic principles. Many estimates of natural-gas resources have been made by the USGS, beginning with the work of Eugene Shaw in 1919. Various techniques have been employed over the years in a series of natural-gas assessments that have continued episodically almost to the present day. Like previous assessments, the one currently underway is intended to reflect the situation, needs, and understanding of oil and gas resources most relevant to themore » needs of the United States at the present time. 46 refs., 4 figs.« less

COMMON /BLK2/ XX(234), ND(6), 0(6),INOD COMMON /OFILE/ DINFI LE,McTNd C) ,1 ECOO

Southeastern Alaska is a geologically complex region that contains,a wide variety of known beatable mineral deposits, some of which have produced very important amounts of!metals and other materials during the past 100plus years.The Juneau district, the Chichagof district, the Kasaan Peninsula Bokan Mountain, and the Hyder district are ail well known productive localities.In recent years major new discoveries have been made at the Green's Creek mine and the Quartz Hill molybdenite property.This report estimates the undiscovered beatable mineral-resource the undiscovered mineral-resource endowment of the Tongass National the region; and, finally, itestimates the undiscovered mineral-resource was open to mineral entry as of October, 1990.The lands open to half of the undiscovered beatable mineral resource endowment of Regional geobgic, economic geologic, geochemical, geophysbal, endowment of all of the region; it then estimates Forest, which covers about 80 percent of endowment of that part of the Tongass that mineral entry are estimated to contain slightly over the regbn.and mineral exploration history information for the region have been integrated to define 124 tracts that are permissive for the occurrence of undiscovered locatable mineral resources.The tracts range in size from about 12 to 2,920 square kibmeters in area and cover almost ail parts of the region.Some tracts are wholly in the Tongass National Forest, others are partially within or wholly outside.Areas not assigned to tracts are interpreted to have no undiscovered mineral-resource endowment, based on available data.The mineral-resource endowment estimates for all of the individual estimate of the undiscovered locatable mineral-resource endowment lands in southeastern Alaska.That estimate is 5.04 million metric tonnes molybdenum, 168 metrb tonnes of gold, 2.22 million metric tonne metric tonnes of lead, 129 million metric tonnes of iron, 0.167 million tonnes of rare-earth-element oxides, 2,770 metric tonnes of uranium tonnes of antimony, 0.181 million metric tonnes of tin, and 2,500 Regarding leasable and other beatable mineral resources: no oil or gas resources of of economic interest are judged to exist in southeastern Alaska, but coal, dimension stone, and the industrial minerals barite, limestone, and marble have been produced in the past.They are described briefly in this report, but no quantification of their value is given.Geothermal energy is also discussed and previous quantified resource estimates made by others are included.Rock for aggregate, sand, and gravel are salable mineral resources of continuing importance, but they are neither discussed nor evaluated in this report.and Scott G eotogical and Geophysical Surveys for assistance ctivities in southeastern Alaska.Informal review of a mfew parts were read by D.A. Singer.