Geology Reports⌕ Search

Geology topics

T. R. Klett

Publications and source records attributed to T. R. Klett.

At least 37 records · Page 2Linked to original sources
USGS2008

An Approach to the Classification of Potential Reserve Additions of Giant Oil Fields of the World

This report contains slides and notes for slides for a presentation given to the Committee on Sustainable Energy and the Ad Hoc Group of Experts on Harmonization of Fossil Energy and Mineral Resources Terminology on 17 October 2007 in Geneva, Switzerland. The presentation describes the U.S. Geological Survey study to characterize and quantify petroleum-reserve additions, and the application of this study to help classify the quantities.

Open-File Report↗
USGS2007

Chapter 2: Tabular Data and Graphical Images in Support of the U.S. Geological Survey National Oil and Gas Assessment - The Wind River Basin Province

This chapter describes data used in support of the process being applied by the U.S. Geological Survey (USGS) National Oil and Gas Assessment (NOGA) project. Digital tabular data used in this report and archival data that permit the user to perform further analyses are available elsewhere on this CD-ROM. Computers and software may import the data without transcription from the Portable Document Format files (.pdf files) of the text by the reader. Graphical images are provided as .pdf files and tabular data are provided in a raw form as tab-delimited text files (.tab files) because of the number and variety of platforms and software available.

Data Series↗
USGS2007

An Evaluation of the USGS World Petroleum Assessment 2000 - Supporting Data

Introduction In June 2000, the U.S. Geological Survey (USGS) published the results of a world petroleum assessment (exclusive of the United States), based on data current through 1995 (U.S. Geological Survey World Energy Assessment Team, 2000). The assessment included the volumes of undiscovered crude oil and natural gas estimated to have the potential to be added to reserves in a 30-year time frame (to 2025). Klett and others (2005) compared the actual additions to reserves as reported from January 1996 to December 2003 (IHS Energy, 2003) with those estimates, apportioned to the 1996-2003 period (27 percent of the 30-year time frame). The present report (1) provides tabular data, not included in the 2005 report by Klett and others, that support the graphical displays and (2) briefly summarizes the interpretations and conclusions presented in the 2005 report. Approximately 28 percent of the additions to oil reserves by reserve growth and approximately 11 percent of the estimated undiscovered oil volumes that were estimated for the World Petroleum Assessment 2000 (U.S. Geological Survey World Energy Assessment Team, 2000) were realized in the 8 years since that assessment. Slightly more than half of the estimated additions to gas reserves by reserve growth and approximately 10 percent of the estimated undiscovered gas volumes were realized. Between 1995 and 2003, growth of oil reserves in previously discovered fields exceeded new-field discoveries as a source of global additions to reserves of conventional oil by a factor of about 3 to 1. The greatest amount of reserve growth for crude oil was in the Middle East and North Africa, whereas the greatest contribution from new-field discoveries was in Sub-Saharan Africa. The greatest amount of reserve growth for natural gas was in the Middle East and North Africa, whereas the greatest contribution from new-field discoveries was in the Asia Pacific region. On an energy-equivalent basis, volumes of new gas field discoveries exceeded new oil field discoveries. The graphs are based on the data listed in tables 1 and 2.

Open-File Report↗
USGS2007

U.S. Geological Survey assessment concepts for conventional petroleum accumulations: Chapter 24 in Petroleum systems and geologic assessment of oil and gas in the San Joaquin Basin Province, California

Conventional petroleum accumulations are discrete fields or pools localized in structural or stratigraphic traps by the buoyancy of oil or gas in water; they float, bubble-like, in water. This report describes the fundamental concepts supporting the U.S. Geological Survey “Seventh Approximation” model for resource assessments of conventional accumulations. The Seventh Approximation provides a strategy for estimating volumes of undiscovered petroleum (oil, gas, and coproducts) having the potential to be added to reserves in a 30-year forecast span. The assessment of an area requires (1) choice of a minimum accumulation size, (2) assignment of geologic and access risk, and (3) estimation of the number and sizes of undiscovered accumulations in the assessment area. The combination of these variables yields probability distributions for potential additions to reserves. Assessment results are controlled by geology-based input parameters supplied by knowledgeable geologists, as opposed to projections of historical trends.

Professional Paper↗
USGS2007

U.S. Geological Survey input-data form and operational procedure for the assessment of conventional petroleum accumulations: Chapter 25 in Petroleum systems and geologic assessment of oil and gas in the San Joaquin Basin Province, California

The U.S. Geological Survey model for undiscovered conventional accumulations is designed to aid in the assessment of crude oil, natural gas, and natural gas liquids (collectively called petroleum) resources. Conventional accumulations may be described in terms of discrete fields or pools localized in structural and stratigraphic traps by the buoyancy of oil or natural gas in water. Conventional accumulations are commonly bounded by a down-dip water contact. The assessment model requires estimates of the number and sizes of undiscovered conventional accumulations. Technically recoverable petroleum resources from undiscovered conventional accumulations are calculated by statistically combining probability distributions of the estimated number and sizes of undiscovered accumulations, along with associated risks and coproduct ratios. Probabilistic estimates of petroleum resources are given for oil in oil accumulations, gas (associated/dissolved) in oil accumulations, natural gas liquids in oil accumulations, gas (nonassociated) in gas accumulations, and total liquids (oil and natural gas liquids) in gas accumulations.

Professional Paper↗
USGS2007

A Monte Carlo simulation method for the assessment of undiscovered, conventional oil and gas: Chapter 26 in Petroleum systems and geologic assessment of oil and gas in the San Joaquin Basin Province, California

The U.S. Geological Survey has developed two Monte Carlo programs for assessment of undiscovered conventional oil and gas resources. EMCEE (for Energy Monte Carlo) and Emc2 (for Energy Monte Carlo program 2) are programs that calculate probabilistic estimates of undiscovered resources based on input distributions for numbers and sizes of undiscovered fields. Emc2 uses specific types of distributions for the input, whereas EMCEE allows greater flexibility of the input distribution types.

Professional Paper↗
USGS2007

Data sources and compilation: Chapter 27 in Petroleum systems and geologic assessment of oil and gas in the San Joaquin Basin Province, California

Geologic, production, and exploration/discovery-history data are used by the U.S. Geological Survey to aid in the assessment of petroleum resources. These data, as well as the broad knowledge and experience of the assessing geologists, are synthesized to provide, for each assessment unit, geologic and exploration models upon which estimates are made of the number and sizes of undiscovered accumulations for conventional assessment units or number and total recoverable volumes of untested cells for continuous assessment units (input data for resource calculations). Quantified geologic information and trends in production and exploration/discovery-history data with respect to time and exploration effort provide guides for the estimating parameters of variables recorded on the input-data forms (input data) used to calculate petroleum resources. An Assessment Review Team reviews proposed geologic and exploration models and input data for each assessment unit in formal assessment meetings. The Assessment Review Team maintains the accuracy and consistency of the assessment procedure during the formal assessment meetings.

Professional Paper↗
USGS2007

Tabular data and graphical images in support of the U.S. Geological Survey National Oil and Gas Assessment -- San Joaquin Basin (5010): Chapter 28 in Petroleum systems and geologic assessment of oil and gas in the San Joaquin Basin Province, California

This chapter describes data used in support of the assessment process. Digital tabular data used in this report and archival data that permit the user to perform further analyses are available elsewhere on this CD–ROM. Computers and software may import the data without transcription from the portable document format (.pdf) files of the text by the reader. Because of the number and variety of platforms and software available, graphical images are provided as .pdf files and tabular data are provided in a raw form as tab-delimited text files (.tab files).

California↗
USGS2006

Chapter 3. Tabular data and graphical images in support of the U.S. Geological Survey National Oil and Gas Assessment--East Texas basin and Louisiana-Mississippi salt basins provinces, Jurassic Smackover Interior salt basins total petroleum system (504902), Cotton Valley group

This chapter describes data used in support of the process being applied by the U.S. Geological Survey (USGS) National Oil and Gas Assessment (NOGA) project. Digital tabular data used in this report and archival data that permit the user to perform further analyses are available elsewhere on the CD-ROM. Computers and software may import the data without transcription from the Portable Document Format files (.pdf files) of the text by the reader. Because of the number and variety of platforms and software available, graphical images are provided as .pdf files and tabular data are provided in a raw form as tab-delimited text files (.tab files).

Alabama, Arkansas. Florida, Georgia, Louisiana, Mi↗
USGS2006

Chapter 3: Tabular Data and Graphical Images in Support of the U.S. Geological Survey National Oil and Gas Assessment - Western Gulf Province, Smackover-Austin-Eagle Ford Composite Total Petroleum System (504702)

This chapter describes data used in support of the process being applied by the U.S. Geological Survey (USGS) National Oil and Gas Assessment (NOGA) project. Digital tabular data used in this report and archival data that permit the user to perform further analyses are available elsewhere on this CD-ROM. Computers and software may import the data without transcription from the Portable Document Format files (.pdf files) of the text by the reader. Because of the number and variety of platforms and software available, graphical images are provided as .pdf files and tabular data are provided in a raw form as tab-delimited text files (.tab files).

Data Series↗
USGS2006

Assessment of undiscovered technically recoverable conventional petroleum resources of northern Afghanistan

Using a geology-based assessment methodology, the U.S. Geological Survey - Afghanistan Ministry of Mines and Industry Joint Oil and Gas Resource Assessment Team estimated mean volumes of undiscovered petroleum in northern Afghanistan; the resulting estimates are 1.6 billion barrels (0.2 billion metric tons) of crude oil, 16 trillion cubic feet (0.4 trillion cubic meters) of natural gas, and 0.5 billion barrels (0.8 billion metric tons) of natural gas liquids. Most of the undiscovered crude oil is in the Afghan-Tajik Basin and most of the undiscovered natural gas is in the Amu Darya Basin. Four total petroleum systems were identified, and these were subdivided into eight assessment units for the purpose of this resource assessment. The area with the greatest potential for undiscovered natural gas accumulations is in Upper Jurassic carbonate and reef reservoirs beneath an impermeable salt layer in relatively unexplored parts of northern Afghanistan. The Afghan-Tajik Basin has the greatest potential for undiscovered crude oil accumulations, and these are potentially in Cretaceous to Paleogene carbonate reservoir rocks associated with thrust faulting and folding.

Open-File Report↗
USGS2006

Afghan resource assessment fed positive outlook for exploration

Crude oil, natural gas and natural gas liquids/condensate resources are important for the redevelopment of Afghanistan's infrastructure. Improved living and economic conditions in Afghanistan require increasing the availability of energy particularly by exploitation of Afghanistan's petroleum resources. The four total petroleum systems are subdivided into units with homogeneous geologic traits and exploration efforts that include sufficiently homogeneous field-size populations for resource assessment. The greatest volume of undiscovered crude oil is estimated to be in the Afghanistan Eastern Suprasalt Thrusts and Folds Assessment Unit. The greatest volume of undiscovered natural gas is estimated to be in the Afghanistan Jurassic Evaporite Basin Subsalt Carbonates Assessment Unit.

Oil & Gas Journal↗
USGS2005

Guiding principles of USGS methodology for assessment of undiscovered conventional oil and gas resources

During the last 30 years, the methodology for assessment of undiscovered conventional oil and gas resources used by the Geological Survey has undergone considerable change. This evolution has been based on five major principles. First, the U.S. Geological Survey has responsibility for a wide range of U.S. and world assessments and requires a robust methodology suitable for immaturely explored as well as maturely explored areas. Second, the assessments should be based on as comprehensive a set of geological and exploration history data as possible. Third, the perils of methods that solely use statistical methods without geological analysis are recognized. Fourth, the methodology and course of the assessment should be documented as transparently as possible, within the limits imposed by the inevitable use of subjective judgement. Fifth, the multiple uses of the assessments require a continuing effort to provide the documentation in such ways as to increase utility to the many types of users. Undiscovered conventional oil and gas resources are those recoverable volumes in undiscovered, discrete, conventional structural or stratigraphic traps. The USGS 2000 methodology for these resources is based on a framework of assessing numbers and sizes of undiscovered oil and gas accumulations and the associated risks. The input is standardized on a form termed the Seventh Approximation Data Form for Conventional Assessment Units. Volumes of resource are then calculated using a Monte Carlo program named Emc2, but an alternative analytic (non-Monte Carlo) program named ASSESS also can be used. The resource assessment methodology continues to change. Accumulation-size distributions are being examined to determine how sensitive the results are to size-distribution assumptions. The resource assessment output is changing to provide better applicability for economic analysis. The separate methodology for assessing continuous (unconventional) resources also has been evolving. Further studies of the relationship between geologic models of conventional and continuous resources will likely impact the respective resource assessment methodologies. ?? 2005 International Association for Mathematical Geology.

Conference Paper↗
USGS2005

United States geological survey's reserve-growth models and their implementation

The USGS has developed several mathematical models to forecast reserve growth of fields both in the United States (U.S.) and the world. The models are based on historical reserve growth patterns of fields in the U.S. The patterns of past reserve growth are extrapolated to forecast future reserve growth. Changes of individual field sizes through time are extremely variable, therefore, the reserve growth models take on a statistical approach whereby volumetric changes for populations of fields are used in the models. Field age serves as a measure of the field-development effort that is applied to promote reserve growth. At the time of the USGS World Petroleum Assessment 2000, a reserve growth model for discovered fields of the world was not available. Reserve growth forecasts, therefore, were made based on a model of historical reserve growth of fields of the U.S. To test the feasibility of such an application, reserve growth forecasts were made of 186 giant oil fields of the world (excluding the U.S. and Canada). In addition, forecasts were made for these giant oil fields subdivided into those located in and outside of Organization of Petroleum Exporting Countries (OPEC). The model provided a reserve-growth forecast that closely matched the actual reserve growth that occurred from 1981 through 1996 for the 186 fields as a whole, as well as for both OPEC and non-OPEC subdivisions, despite the differences in reserves definition among the fields of the U.S. and the rest of the world. ?? 2005 International Association for Mathematical Geology.

Conference Paper↗
USGS2005

An evaluation of the U.S. Geological Survey World Petroleum Assessment 2000

This study compares the additions to conventional crude oil and natural gas reserves as reported from January 1996 to December 2003 with the estimated undiscovered and reserve-growth volumes assessed in the U.S. Geological Survey World Petroleum Assessment 2000, which used data current through 1995. Approximately 28% of the estimated additions to oil reserves by reserve growth and approximately 11% of the estimated undiscovered oil volumes were realized in the 8 yr since the assessment (27% of the time frame for the assessment). Slightly more than half of the estimated additions to gas reserves by reserve growth and approximately 10% of the estimated undiscovered gas volumes were realized. Between 1995 and 2003, growth of oil reserves in previously discovered fields exceeded new-field discoveries as a source of global additions to reserves of conventional oil by a ratio of 3:1. The greatest amount of reserve growth for crude oil occurred in the Middle East and North Africa, whereas the greatest contribution from new-field discoveries occurred in sub-Saharan Africa. The greatest amount of reserve growth for natural gas occurred in the Middle East and North Africa, whereas the greatest contribution from new-field discoveries occurred in the Asia Pacific region. On an energy-equivalent basis, volumes of new gas-field discoveries exceeded new oil-field discoveries. Copyright ?? 2005. The American Association of Petroleum Geologists. All rights reserved.

American Association of Petroleum Geologists Bulle↗
USGS2003

Graphic comparison of reserve-growth models for conventional oil and accumulation

The U.S. Geological Survey (USGS) periodically assesses crude oil, natural gas, and natural gas liquids resources of the world. The assessment procedure requires estimated recover-able oil and natural gas volumes (field size, cumulative production plus remaining reserves) in discovered fields. Because initial reserves are typically conservative, subsequent estimates increase through time as these fields are developed and produced. The USGS assessment of petroleum resources makes estimates, or forecasts, of the potential additions to reserves in discovered oil and gas fields resulting from field development, and it also estimates the potential fully developed sizes of undiscovered fields. The term ?reserve growth? refers to the commonly observed upward adjustment of reserve estimates. Because such additions are related to increases in the total size of a field, the USGS uses field sizes to model reserve growth. Future reserve growth in existing fields is a major component of remaining U.S. oil and natural gas resources and has therefore become a necessary element of U.S. petroleum resource assessments. Past and currently proposed reserve-growth models compared herein aid in the selection of a suitable set of forecast functions to provide an estimate of potential additions to reserves from reserve growth in the ongoing National Oil and Gas Assessment Project (NOGA). Reserve growth is modeled by construction of a curve that represents annual fractional changes of recoverable oil and natural gas volumes (for fields and reservoirs), which provides growth factors. Growth factors are used to calculate forecast functions, which are sets of field- or reservoir-size multipliers. Comparisons of forecast functions were made based on datasets used to construct the models, field type, modeling method, and length of forecast span. Comparisons were also made between forecast functions based on field-level and reservoir- level growth, and between forecast functions based on older and newer data. The reserve-growth model used in the 1995 USGS National Assessment and the model currently used in the NOGA project provide forecast functions that yield similar estimates of potential additions to reserves. Both models are based on the Oil and Gas Integrated Field File from the Energy Information Administration (EIA), but different vintages of data (from 1977 through 1991 and 1977 through 1996, respectively). The model based on newer data can be used in place of the previous model, providing similar estimates of potential additions to reserves. Fore-cast functions for oil fields vary little from those for gas fields in these models; therefore, a single function may be used for both oil and gas fields, like that used in the USGS World Petroleum Assessment 2000. Forecast functions based on the field-level reserve growth model derived from the NRG Associates databases (from 1982 through 1998) differ from those derived from EIA databases (from 1977 through 1996). However, the difference may not be enough to preclude the use of the forecast functions derived from NRG data in place of the forecast functions derived from EIA data. Should the model derived from NRG data be used, separate forecast functions for oil fields and gas fields must be employed. The forecast function for oil fields from the model derived from NRG data varies significantly from that for gas fields, and a single function for both oil and gas fields may not be appropriate.

Bulletin↗