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Emil D. Attanasi

Publications and source records attributed to Emil D. Attanasi.

At least 55 records · Page 3Linked to original sources
USGS2007

Prediction of resource volumes at untested locations using simple local prediction models

This paper shows how local spatial nonparametric prediction models can be applied to estimate volumes of recoverable gas resources at individual undrilled sites, at multiple sites on a regional scale, and to compute confidence bounds for regional volumes based on the distribution of those estimates. An approach that combines cross-validation, the jackknife, and bootstrap procedures is used to accomplish this task. Simulation experiments show that cross-validation can be applied beneficially to select an appropriate prediction model. The cross-validation procedure worked well for a wide range of different states of nature and levels of information. Jackknife procedures are used to compute individual prediction estimation errors at undrilled locations. The jackknife replicates also are used with a bootstrap resampling procedure to compute confidence bounds for the total volume. The method was applied to data (partitioned into a training set and target set) from the Devonian Antrim Shale continuous-type gas play in the Michigan Basin in Otsego County, Michigan. The analysis showed that the model estimate of total recoverable volumes at prediction sites is within 4 percent of the total observed volume. The model predictions also provide frequency distributions of the cell volumes at the production unit scale. Such distributions are the basis for subsequent economic analyses. ?? Springer Science+Business Media, LLC 2007.

Natural Resources Research↗
USGS2007

Statistics of petroleum exploration in the world outside the United States and Canada through 2001

Future oil and gas supplies depend, in part, on the reserves that are expected to be added through exploration and new discoveries. This Circular presents a summary of the statistics and an analysis of petroleum exploration in the world outside the United States and Canada (the study area) through 2001. It updates U.S. Geological Survey Circular 1096 (by E.D. Attanasi and D.H. Root, 1993) and expands coverage of the statistics to areas where drilling and discovery data have recently become available. These new areas include China, the formerly Communist countries of Eastern Europe, and the countries that once were part of the former Soviet Union in Europe and Asia. Data are presented by country but are organized by petroleum provinces delineated by the U.S. Geological Survey World Energy Assessment Team (USGS Digital Data Series DDS?60, published in 2000). The data and analysis are presented in maps and graphs, providing a visual summary of the exploration maturity of an area. The maps show the delineated prospective areas and explored areas through 2001; explored areas have a drilling density that would rule out the occurrence of undetected large petroleum accumulations. Graphs summarize the exploration yields in terms of cumulative recoverable discovered oil and gas by delineated prospective area. From 1992 through 2001 in areas outside the United States and Canada, the delineated prospective area expanded at a rate of about 50,000 square miles per year while the explored area grew at the rate of about 11,000 square miles per year. The delineated prospective area established by 1970 contains about 75 percent of the oil discovered to date in the study area. This area is slightly less than 40 percent of the delineated prospective area established through 2001. Maps and graphs show the extension of the delineated prospective area to deepwater areas offshore of Brazil and West Africa. From 1991 through 2000, offshore discoveries accounted for 59 percent of the oil and 77 percent of the gas discovered in the study area. The petroleum industry's decision to incur the greater costs of moving offshore and into deeper waters appears to be a response to the absence of onshore prospects of comparable quality. Where natural gas can be commercially developed and marketed, data show an expansion of exploration to target gas-prone areas.

Circular↗
USGS2007

Heavy oil and natural bitumen resources in geological basins of the world

Heavy oil and natural bitumen are oils set apart by their high viscosity (resistance to flow) and high density (low API gravity). These attributes reflect the invariable presence of up to 50 weight percent asphaltenes, very high molecular weight hydrocarbon molecules incorporating many heteroatoms in their lattices. Almost all heavy oil and natural bitumen are alteration products of conventional oil. Total resources of heavy oil in known accumulations are 3,396 billion barrels of original oil in place, of which 30 billion barrels are included as prospective additional oil. The total natural bitumen resource in known accumulations amounts to 5,505 billion barrels of oil originally in place, which includes 993 billion barrels as prospective additional oil. This resource is distributed in 192 basins containing heavy oil and 89 basins with natural bitumen. Of the nine basic Klemme basin types, some with subdivisions, the most prolific by far for known heavy oil and natural bitumen volumes are continental multicyclic basins, either basins on the craton margin or closed basins along convergent plate margins. The former includes 47 percent of the natural bitumen, the latter 47 percent of the heavy oil and 46 percent of the natural bitumen. Little if any heavy oil occurs in fore-arc basins, and natural bitumen does not occur in either fore-arc or delta basins.

Open-File Report↗
USGS2007

Economic decision making and the application of nonparametric prediction models

Sustained increases in energy prices have focused attention on gas resources in low permeability shale or in coals that were previously considered economically marginal. Daily well deliverability is often relatively small, although the estimates of the total volumes of recoverable resources in these settings are large. Planning and development decisions for extraction of such resources must be area-wide because profitable extraction requires optimization of scale economies to minimize costs and reduce risk. For an individual firm the decision to enter such plays depends on reconnaissance level estimates of regional recoverable resources and on cost estimates to develop untested areas. This paper shows how simple nonparametric local regression models, used to predict technically recoverable resources at untested sites, can be combined with economic models to compute regional scale cost functions. The context of the worked example is the Devonian Antrim shale gas play, Michigan Basin. One finding relates to selection of the resource prediction model to be used with economic models. Models which can best predict aggregate volume over larger areas (many hundreds of sites) may lose granularity in the distribution of predicted volumes at individual sites. This loss of detail affects the representation of economic cost functions and may affect economic decisions. Second, because some analysts consider unconventional resources to be ubiquitous, the selection and order of specific drilling sites may, in practice, be determined by extraneous factors. The paper also shows that when these simple prediction models are used to strategically order drilling prospects, the gain in gas volume over volumes associated with simple random site selection amounts to 15 to 20 percent. It also discusses why the observed benefit of updating predictions from results of new drilling, as opposed to following static predictions, is somewhat smaller. Copyright 2007, Society of Petroleum Engineers.

Conference Paper↗
USGS2007

Natural bitumen and extra-heavy oil

Since 2005, oil price increases have greatly increased investment in the production of extra- heavy oil and natural bitumen (tar sands or oil sands) to supplement conventional oil supplies. These oils are characterised by their high viscosity, high density (low API gravity), and high concentrations of nitrogen, oxygen, sulphur, and heavy metals. Extra-heavy oil and natural bitumen are the remnants of very large volumes of conventional oils that have been generated and subsequently degraded, principally by bacterial action. Chemically and texturally, they resemble the residuum produced by refinery distillation of light oil. Although these viscous oils are much more costly to extract, transport and refine than conventional oils, production levels have increased to more than 1.6 million barrels per day, or just under 2% of world crude oil production. The resource base of extra-heavy oil and natural bitumen is immense and can easily support a substantial expansion in production. This resource base can make a major contribution to oil supply, if it can be extracted and transformed into useable refinery feedstock at sufficiently high rates and at costs that are competitive with alternative resources. Technology must continue to be developed to address emerging challenges (both environmental and economic) in the market supply chain.

Book chapter↗
USGS2004

A bootstrap approach to computing uncertainty in inferred oil and gas reserve estimates

This study develops confidence intervals for estimates of inferred oil and gas reserves based on bootstrap procedures. Inferred reserves are expected additions to proved reserves in previously discovered conventional oil and gas fields. Estimates of inferred reserves accounted for 65% of the total oil and 34% of the total gas assessed in the U.S. Geological Survey’s 1995 National Assessment of oil and gas in US onshore and State offshore areas. When the same computational methods used in the 1995 Assessment are applied to more recent data, the 80-year (from 1997 through 2076) inferred reserve estimates for pre-1997 discoveries located in the lower 48 onshore and state offshore areas amounted to a total of 39.7 billion barrels of oil (BBO) and 293 trillion cubic feet (TCF) of gas. The 90% confidence interval about the oil estimate derived from the bootstrap approach is 22.4 BBO to 69.5 BBO. The comparable 90% confidence interval for the inferred gas reserve estimate is 217 TCF to 413 TCF. The 90% confidence interval describes the uncertainty that should be attached to the estimates. It also provides a basis for developing scenarios to explore the implications for energy policy analysis.

Natural Resources Research↗
USGS2004

Size-frequency analysis of petroleum accumulations in selected United States plays: potential analogues for frontier areas

This report presents the petroleum accumulation size-frequency relationships of selected mature plays assessed in the U.S. Geological Survey's 1995 National Assessment of Oil and Gas Resources. The plays provide assessors with potential analogue models from which to estimate the numbers of undiscovered accumulations in medium and smaller size categories. Each play selected was required to have at least 50 discovered accumulations. Discovered accumulations plus the mean number of undiscovered accumulations equals the total accumulations assessed at the play level. There were 36 plays that met the criteria for oil accumulations and 25 plays that met the criteria for gas accumulations. Other properties of the plays such as primary trap type, lithology, depth, and hydrocarbon characteristics are also provided to assist the geologist in choosing an appropriate analogue. The text explains how the analogue size-frequency relationships can be used to estimate the number of small and medium size accumulations for frontier-area plays or partially explored plays in high cost areas. Although this document has been written in support of the Alaska North Slope Assessment, the basic size?frequency relationships provided are applicable elsewhere.

Open-File Report↗
USGS2004

Natural bitumen and extra-heavy oil

Crude oil is found in sedimentary rocks throughout the world, except, thus far, in Antarctica. In many places the oil has been degraded, so that it is represented by viscous black oil that is difficult to recover, transport, and refine. Depending upon the degree of degradation the result is extra-heavy oil or, in the extreme case, natural bitumen. Except in Canada, precise quantitative reserves and oilin-place data on a reservoir basis are seldom available because most countries and companies consider such information to be proprietary. Natural bitumen is the oil contained in clastic and carbonate reservoir rocks, most frequently in small deposits at, or near, the earth’s surface. These rocks are commonly referred to as tar sands or oil sands and have been mined since antiquity for use as paving. Occasionally such deposits are extremely large in areal extent and in contained resources, most notably those in northern Alberta, Canada. In 2003 only the Alberta bitumen deposits were being exploited as a source of crude oil. Similarly, reservoirs containing extra-heavy oil are geographically widespread but only one such deposit is sufficiently large to have a major supply and economic impact. That deposit is the Orinoco Oil Belt in Eastern Venezuela. Nowhere else in the world is such a concentration of extra heavy oil known or likely to exist. Definitions of terms used in this commentary may be found immediately prior to Table 4.1. The resource definitions are those of the World Petroleum Congress-Society of Petroleum Engineers-American Association of Petroleum Geologists, with minor additions. One such addition, e.g. is the term Original Reserves, comprised of Proved Reserves plus Cumulative Production, which tends to place new and mature reservoirs on a more nearly comparable basis than either term alone

Conference Paper↗
USGS2003

Uncertainty and inferred reserve estimates — The 1995 National Assessment

Inferred reserves are expected additions to proved reserves of oil and gas fields discovered as of a certain date. Inferred reserves accounted for 65 percent of the total oil and 34 percent of the total gas assessed in the U.S. Geological Survey's 1995 National Assessment of oil and gas in onshore and State offshore areas. The assessment predicted that over the 80-year period from 1992 through 2071, the sizes of pre-1992 discoveries in the lower 48 onshore and State offshore areas will increase by 48 billion barrels of oil (BBO) and 313 trillion cubic feet of wet gas (TCF). At that time, only point estimates were reported. This study presents a scheme to compute confidence intervals for these estimates. The recentered 90 percent confidence interval for the estimated inferred oil of 48 BBO is 25 BBO and 82 BBO. Similarly, the endpoints of the confidence interval about inferred reserve estimate of 313 TCF are 227 TCF and 439 TCF. The range of the estimates provides a basis for development of scenarios for projecting reserve additions and ultimately oil and gas production, information important to energy policy analysis.

Bulletin↗
USGS2002

Some aspects of resource uncertainty and their economic consequences in assessment of the 1002 Area of the Arctic National Wildlife Refuge

Exploration ventures in frontier areas have high risks. Before committing to them, firms prepare regional resource assessments to evaluate the potential payoffs. With no historical basis for directly estimating size distribution of undiscovered accumulations, reservoir attribute probability distributions can be assessed subjectively and used to project undiscovered accumulation sizes. Three questions considered here are: (1) what distributions should be used to characterize the subjective assessments of reservoir attributes, (2) how parsimonious can the analyst be when eliciting subjective information from the assessment geologist, and (3) what are consequences of ignoring dependencies among reservoir attributes? The standard or norm used for comparing outcomes is the computed cost function describing costs of finding, developing, and producing undiscovered oil accumulations. These questions are examined in the context of the US Geological Survey's recently published regional assessment of the 1002 Area of the Arctic National Wildlife Refuge, Alaska. We study effects of using the various common distributions to characterize the geologist's subjective distributions representing reservoir attributes. Specific findings show that triangular distributions result in substantial bias in economic forecasts when used to characterize skewed distributions. Moreover, some forms of the lognormal distribution also result in biased economic inferences. Alternatively, we generally determined four fractiles (100, 50, 5, 0) to be sufficient to capture essential economic characteristics of the underlying attribute distributions. Ignoring actual dependencies among reservoir attributes biases the economic evaluation.

Alaska↗
USGS2002

To sell or not sell: Assessments of Bangladesh hydrocarbons

A decision by the government of Bangladesh to sell or not sell some of its natural gas reserves to neighboring countries in South Asia will be important in determining the economic future of Bangladesh, a country with an area about equal to Wisconsin. Bangladesh is a country of 150 million people, many of whom live at or below the poverty line. It is situated almost entirely on the great low-lying delta of the Ganges and Brahmaputra River systems. Folded Tertiary strata that form hill tracts in easternmost Bangladesh, adjacent India, and Myanmar provide a little relief above a monotonous deltaic terrain (Fig. 1).

Oil & Gas Journal↗
USGS1997

Reserve growth important to U.S. gas supply

Reserve growth is a major component of the remaining U.S. natural gas resources. Historical data support this premise, as do estimates of technically recoverable and of economically recoverable gas resources remaining in the U.S. However, reserve growth is still poorly understood. Hence, much work remains to be done on the phenomenon of reserve growth.

Oil & Gas Journal↗
USGS1994

The enigma of oil and gas field growth

Growth in estimates of recovery in discovered fields is an important source of annual additions to United States proved reserves. This paper examines historical field growth and presents estimates of future additions to proved reserves from fields discovered before 1992. Field-level data permitted the sample to be partitioned on the basis of recent field growth patterns into outlier and common field sets, and analyzed separately. The outlier field set accounted for less than 15% of resources, yet grew proportionately six times as much as the common fields. Because the outlier field set contained large old heavy-oil fields and old low-permeability gas fields, its future growth is expected to be particularly sensitive to prices. A lower bound of a range of estimates of futu e growth was calculated by applying monotone growth functions computed from the common field set to all fields. Higher growth estimates were obtained by extrapolating growth of the common field set and assuming the outlier fields would maintain the same share of total growth that occurred from 1978 through 1991. By 2020, the two estimates for additions to reserves from pre-1992 fields are 23 and 32 billion bbl of oil in oil fields and 142 and 195 tcf of gas in gas fields.

American Association of Petroleum Geologists Bulle↗