Tighter new regulation of stack gas emissions and competition in power generation are driving electrical utilities to demand cleaner, lower sulfur coal. Historical data on sulfur content of produced coals shows little variability in coal quality for individual mines and individual coal-producing counties over relatively long periods of time. If coal-using power generators follow the compliance patterns established in Phase I of the 1990 Clean Air Act Amendments, then the industry’s response to the tighter Phase II emissions standards will result in large amounts of coal production shifting from higher sulfur areas to areas with lower cost low sulfur coal. One reason this shift will likely occur is that currently only 30% of U.S. coal-fired electrical generating capacity is equipped with flue-gas scrubbers. In 1995, coal mines in the higher sulfur areas of the Illinois Basin and Northern and Central Appalachia employed 78% of all coal miners (>70,000 miners). A substantial geographical redistribution of the nation’s coal supplies will likely lead to economic dislocations that will reach beyond local coal-producing areas.

This report describes the data, methods, and national and regional estimates of inferred reserves from the 1995 U. S. Geological Survey's National Assessment of Oil and Gas Resources.Over the next 80 years, about 60 billion barrels of oil and 322 trillion cubic feet of gas are expected to be added to oil and gas fields discovered prior to 1992.More than half of the estimated inferred reserves of oil in the Lower 48 States are in regions 5 (West Texas and Eastern New Mexico) and 2 (Pacific Coast).Almost two-thirds of the estimated inferred reserves of gas are in regions 6 (Gulf Coast) and 7 (Midcontinent).

The occurrence and quantity of world petroleum resources appears to be well understood. The numbers are so great, however, that even minor variants in the total picture can be responsible for enormous localized industrial activity. Specific knowledge of the widespread local occurrences of oil and gas, therefore, is important to economic development and to the free market distribution of energy. It is also clear, however, that a large proportion of the recoverable petroleum resources are found in only a few selected localities. We believe that, worldwide, recoverable conventional oil and gas exist in ultimate quantities approximating 2300 billion barrels (370 Gm3) of oil and 12 000 trillion cubic feet (340 TM3) of gas. These values are limited by our concepts of world petroleum geology and our understanding of specific basins; nonetheless, continued expansion of exploration activity, around the world, has resulted in only minimal adjustments to our quantitative understanding of ultimate resources. Reserves reporting has been one of the greatest hindrances to a thorough understanding of world resources because we are just now gaining an understanding of field growth and what is actually being calculated and reported from various localities. Unconventional resources are present in large quantities, in particular in the Western Hemisphere, and are of a dimension to substantially contribute to world reserves should economic conditions permit.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAn Alternative Method for the Reduction of Thermodynamic DerivativesD. H. Root , H. T. Haselton , and I-Ming Chou Cite this: J. Chem. Educ. 1994, 71, 4, 303Publication Date (Print):April 1, 1994Publication History Received3 August 2009Published online1 April 1994Published inissue 1 April 1994https://doi.org/10.1021/ed071p303RIGHTS & PERMISSIONSArticle Views120Altmetric-Citations1LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Get e-Alerts Get e-Alerts

This circular presents a summary of the geographic location, amount, and results of petroleum exploration, including an atlas showing explored and delineated prospective areas through 1990. The data show that wildcat well drilling has continued through the last decade to expand the prospective area by about 40,000 to 50,000 square miles per year. However, the area delineated by 1970, which represents only about one-third of the prospective area delineated to date, contains about 80 percent of the oil discovered to date. This discovery distribution suggests that, from an overall prospective, the industry was successful in delineating the most productive areas early. The price increases of the 1970's and 1980's allowed the commercial exploration and development of fields in high-cost areas, such as the North Sea and Campos Basin, Brazil. Data on natural-gas discoveries also indicate that gas will be supplying an increasing share of the worldwide energy market. The size distribution of petroleum provinces is highly skewed. The skewed distribution and the stability in province size orderings suggest that intense exploration in identified provinces will not change the distribution of oil within the study area. Although evidence of the field-growth phenomenon outside the United States and Canada is presented, the data are not yet reliable enough for projecting future growth. The field-growth phenomenon implies not only that recent discoveries are substantially understated, but that field growth could become the dominant source of additions to proved reserves in the future.

The search for petroleum has expanded to include most countries in the world. From January 1, 1950, through 1980, about 160,000 crew months were spent in geologic and geophysical exploration in a study area that includes all nonCommunist countries outside the United States and Canada. By the end of 1982, almost 27,000 wildcat wells had been drilled in this study area; these and other pre-1983 wells delineated a prospective area of 1.56 million square miles in which about 836 billion barrels of ultimately recoverable crude oil has been found, 62 percent of it since 1950. The delineated prospective area is still expanding at a rate of 56,000 square miles per year (60 square miles per wildcat well) for the study area, and it is increasing in nearly every country in the study area. Maps of the delineated prospective area in each country show that in most countries, only a small part of the national territory has been explored. In spite of the expansion of the searched area, however, the rate of discovery has declined significantly from 22 million barrels per exploratory well in the 1950's to 8 million barrels per exploratory well in the 1970's.

There is a continual need to update estimates of oil and gas resources remaining to be discovered, and also to refine the methodologies for making these assessments. In 1974, AAPG sponsored a research conference dealing with the above topics, and many of the papers presented there were published in AAPG Studies in Geology 1. As a follow-up to that volume, a U.S. Geological Survey workshop was held in 1983, and many papers from talks presented there, in addition to several other papers, are contained within this volume. The 22 papers have been grouped into two types: those describing methodologies for evaluating resources and those presenting assessments of both conventional and unconventional resources.

OPEC ReviewVolume 10, Issue 3 p. 369-392 Survey and appraisal of US energy resources: production and consumption Dr David H. Root Mathematician, Dr David H. Root Mathematician US Geological Survey, Reston, Virginia, US.Search for more papers by this authorDr Emil D. Attanasi Economist, Dr Emil D. Attanasi Economist US Geological Survey, Reston, Virginia, US.Search for more papers by this author Dr David H. Root Mathematician, Dr David H. Root Mathematician US Geological Survey, Reston, Virginia, US.Search for more papers by this authorDr Emil D. Attanasi Economist, Dr Emil D. Attanasi Economist US Geological Survey, Reston, Virginia, US.Search for more papers by this author First published: September 1986 https://doi.org/10.1111/j.1468-0076.1986.tb00118.xCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume10, Issue3September 1986Pages 369-392 RelatedInformation

World Demonstrated Reserves of crude oil are approximately 723 billion barrels of oil (BBO). Cumulative production is 445 BBO and annual production is 20 BBO. Demonstrated Reserves of crude-oil have declined over the past 10 years consistent with discoveries lagging production over the same period. The assessment of Undiscovered Resources shows a 90 percent probability that the amount discoverable lies between 321 and 1,417 BBO, 550 BBO being the most likely value. The most likely value for Ultimate recoverable resources is 1,718 BBO. The distribution of Ultimate Resources of crude oil will remain highly skewed toward the Middle East; no frontier areas that have potentials large enough to significantly affect present distribution are recognized. Rates of discovery have continued to decline over the past 20 years even though exploration activity has increased in recent years. Prudence dictates, therefore, that the low side of the assessment of Undiscovered Resources be responsibly considered and that alternate energy sources be a part of future planning. Extra-heavy oil and bitumen are assessed separately, with Reserves being figured as the annual productive capacity of installed facilities times 25 years. The annual production of extra-heavy oil is about 8 million barrels and of bitumen about 60 million barrels.

This study examines the temporal properties and determinants of petroleum exploration for firms operating in the Denver basin. Expectations associated with the favorability of a specific areas are modeled by using distributed lag proxy variables (of previous discoveries) and predictions from a discovery process model. In the second part of the study, a discovery process model is linked with a behavioral well-drilling model in order to predict the supply of new reserves. Results of the study indicate that the positive effects of new discoveries on drilling increase for several periods and then diminish to zero within 2-1/2 yr after the deposit discovery date. Tests of alternative specifications of the argument of the distributed lag function using alternative minimum size classes of deposits produced little change in the model's explanatory power. This result suggests that, once an exploration play is underway, favorable operator expectations are substained by the quantity of oil found per time period rather than by the discovery of specific size deposits. 39 references.

The search for petroleum in the Permian Basin of western Texas and eastern New Mexico has produced 4,036 discoveries by the drilling of 30,340 exploratory wells through the end of 1974. This historical discovery record can be used to forecast the number of fields of various sizes that will be discovered by a given number of exploratory wells in the future. The economic costs of discovery and production are related to the sizes of the undiscovered fields; therefore, it is important to estimate the size distribution of the undiscovered fields as well as their total hydrocarbon content. The deeper parts of the basin have not been explored as intensively as the shallower parts. Therefore, we divided the basin into 5,000-ft-depth intervals and made separate forecasts for each interval. The larger future discoveries are anticipated to be made in the deeper intervals. The method of estimating the undiscovered resources and the rate of future discoveries in the Permian Basin is based on a modification of the discovery process model developed by Arps and Roberts.1 The undiscovered recoverable hydrocarbons in the basin after 1974 is estimated to be 6.4 billion bbl of oil equivalent. One-half of this total is expected to be in the 5,000- to 10,000-ft-depth interval, and approximately one-half of the total is estimated to be in 33,000 small fields (less than 1.5 million bbl of recoverable oil equivalent). The future discoveries are estimated for each of 20 1,000-exploratory-well increments, the model forecasts 151 new discoveries, of which 85% will contain less than 1.5 million recoverable bbl of oil equivalent (BOE). Introduction This paper forecasts the number and size of future oil and gas discoveries in the Permian Basin of western Texas and eastern New Mexico. These forecasts were made as part of a study on the economics of petroleum exploration at the regional level. Estimates of the sizes and depths of future discoveries in the basin were necessary to make forecasts useful for discovery- and production-cost analysis. The Permian Basin has a long exploration history that includes the drilling of 30,340 exploratory wells and the discovery of 4,036 oil and gas fields through the end of 1974. Because of this extensive history, we were able to forecast future discoveries by extrapolating the past drilling and discovery record. The method used to forecast the size distribution of future discoveries is based on the well-documented characteristic of the petroleum-discovery process; the large deposits tend to be discovered early in the exploration of an area.1–4 Any reasonable quantitative model of the discovery process must incorporate this qualitative characteristic. The model used here was proposed by Arps and Roberts.1 This model is derived from the following assumption: the probability that the next exploratory well will find a given field is proportional to the ratio of the area of the field to the area of the basin. Thus, a given large field has a higher probability of being discovered early than a given small field. This model originally was devised to forecast the future discoveries in a basin having only a single productive horizon without large structural relief. Therefore, the model must be modified before it can be used in a basin, such as the Permian Basin, that has many productive strata at widely varying depths. In order to apply the model in the Permian Basin, we divided the basin into four layers, each 5,000 ft thick. Forecasts of future discovery rates then were made independently for each layer.

It is well known that the first passage times for Brownian motion have stable laws with exponent $\frac{1}{2}$. It is shown here that first passage times for random walks have distributions in the domain of attraction of a stable law with exponent $\frac{1}{2}$.