United States Assessments of Undiscovered Oil and Gas Resources
Explore US Undiscovered Oil and Gas Assessment Provinces
Assessment results, publications, data and more are available
USGS Energy Resources Program provides periodic assessments of the oil and natural gas endowment of the United States and the World. This website provides access to new, prioritized, assessment results and supporting data for the United States, as part of the Energy Policy and Conservation Act (EPCA).
Assessment Overview
![Image shows a map of the assessment units of the 2018 Delaware Basin oil and gas assessment](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/info_block/public/thumbnails/image/Map%202.jpg?itok=Hqf7Zpca)
The USGS assesses potential for undiscovered oil and gas resources in priority geologic provinces in the United States. This website highlights conventional and unconventional (continuous) oil and gas assessments.
Recent Assessments
Below are the latest US Assessments:
National Oil and Gas Assessment Methodology
The U.S. Geological Survey Energy Resources Program assesses the potential for undiscovered oil and gas resources in priority geologic provinces in the United States and around the world (click here for information about World Oil and Gas Assessments). Two methodologies are used by the USGS; one for assessing conventional oil and gas resources and one for assessing unconventional (continuous) oil and gas resources (such as shale gas and coalbed gas). USGS publications detailing and explaining the conventional and continuous assessment methodologies are provided below. These methodologies have been subjected to rigorous peer reviews by non federal panels, and the two panel reports are provided on this page.
Conventional Resources
USGS Reports
U.S. Geological Survey Assessment Concepts for Conventional Petroleum Accumulations
By James W. Schmoker and T.R. Klett
U.S. Geological Survey Input-Data Form and Operational Procedure for the Assessment of Conventional Petroleum Accumulations
By T.R. Klett, James W. Schmoker, and Ronald R. Charpentier
A Monte Carlo Simulation Method for the Assessment of Undiscovered, Conventional Oil and Gas
By Ronald R. Charpentier and T.R. Klett
Continuous Resources
USGS Reports
U.S. Geological Survey Assessment Concepts for Continuous Petroleum Accumulations
By James W. Schmoker
U.S. Geological Survey Input-Data Form and Operational Procedure for the Assessment Of Continuous Petroleum Accumulations, 2002
By T.R. Klett and James W. Schmoker
Analytic Resource Assessment Method for Continuous Petroleum Accumulations—The ACCESS Assessment Method
By Robert A. Crovelli
FORSPAN Model Users Guide
By T.R. Klett, and Ronald R. Charpentier
Methodology Revisions
Improved USGS methodology for assessing continuous petroleum resources.
Charpentier, R.R., and Cook, T.A.
Applying Probabilistic Well-Performance Parameters to Assessments of Shale-Gas Resources
By Ronald R. Charpentier and Troy Cook
Assembling Probabilistic Performance Parameters of Shale-Gas Wells
By Cook, Troy, and Charpentier, R.R.
USGS Methodology for Assessing Continuous Petroleum Resources
By Ronald R. Charpentier and Troy Cook
New U.S. Geological Survey Method for the Assessment of Reserve Growth
By Timothy R. Klett, Emil D. Attanasi, Ronald R. Charpentier, Troy A. Cook, Philip A. Freeman, Donald L. Gautier, Phuong A. Le, Robert T. Ryder, Christopher J. Schenk, Marilyn E. Tennyson, and Mahendra K. Verma (Reserve Growth Assessment Team)
Variability of Distributions of Well-Scale Estimated Ultimate Recovery for Continuous (Unconventional) Oil and Gas Resources in the United States
By U.S. Geological Survey Oil and Gas Assessment Team
Peer Review
Reserve Growth Methodology
USGS Reports
New U.S. Geological Survey Method for the Assessment of Reserve Growth
By Reserve Growth Assessment Team
Reserve Growth of Oil and Gas Fields - Investigations and Applications
By Troy Cook
Peer Review
Below are a list of recent assessment areas. You can also use the National Oil and Gas Assessment Map to browse these assessments.
Cincinnati Arch Oil and Gas Assessments
Southern Oklahoma Oil and Gas Assessments
Nemaha Uplift Province Oil and Gas Assessment
Forest City Basin Oil and Gas Assessments
Sedgwick Basin Oil and Gas Assessments
Ozark Uplift Oil and Gas Assessments
Iowa Shelf Oil and Gas Assessments
Cambridge Arch-Central Kansas Uplift Oil and Gas Assessment
Marathon Thrust Belt Oil and Gas Assessments
Superior Oil and Gas Assessments
Palo Duro Basin Oil and Gas Assessments
Sioux Arch Oil and Gas Assessments
Below are datasets related to the National Oil and Gas Assessments.
Total organic carbon and pyrolysis analysis data for the Rock Well Petroleum core #8, southern Casper arch, Natrona County, Wyoming
USGS National and Global Oil and Gas Assessment Project-U.S. Gulf Coast, Deep Tuscaloosa Conventional Gas: Assessment Unit Boundary, Assessment Input Data, and Fact Sheet Data Tables
Aggregated Oil and Natural Gas Drilling and Production History of the United States (ver. 1.1, April 2023)
USGS National and Global Oil and Gas Assessment Project-Montana Thrust Belt Province: Assessment Unit Boundaries, Assessment Input Data, and Fact Sheet Data Tables
USGS National and Global Oil and Gas Assessment Project - Resource Allocations for the BLM Carlsbad Planning Area
USGS National and Global Oil and Gas Assessment Project - Williston Basin, Bakken and Three Forks Formations Continuous Assessment Unit Boundaries and Assessment Input Data Forms
Total organic carbon and pyrolysis analysis data for the U.S. Geological Survey Alcova AR-1-13 core hole, Natrona County, Wyoming
USGS National and Global Oil and Gas Assessment Project - Williston Basin, Lower Paleozoic Conventional Assessment Unit Boundaries and Assessment Input Data Forms
USGS National and Global Oil and Gas Assessment Project - Williston Basin, Tyler Formation Assessment Unit Boundaries and Assessment Input Data Forms
USGS National and Global Oil and Gas Assessment Project - Williston Basin, Upper Paleozoic Conventional Assessment Unit Boundaries and Assessment Input Data Forms
USGS National and Global Oil and Gas Assessment Project - Williston Basin, Gas Assessment Unit Boundaries and Assessment Input Data Forms
USGS National and Global Oil and Gas Assessment Project - Northern Alaska Province, Western North Slope Assessment Unit Boundaries and Assessment Input Data Forms
Below are publications associated with this project.
Assessment of undiscovered gas resources in Upper Devonian to Lower Cretaceous strata of the western North Slope, Alaska, 2021
Assessment of continuous gas resources in the Horn River Basin, Cordova Embayment, and Liard Basin, Canada, 2019
Assessment of continuous oil and gas resources in the Mowry Shale, Wind River Basin Province, Wyoming, 2020
Geologic assessment of undiscovered oil and gas resources in the Cherokee Platform area of Kansas, Oklahoma, and Missouri
Structure contour and isopach maps of the Wolfcamp shale and Bone Spring Formation of the Delaware Basin, Permian Basin Province, New Mexico and Texas
Assessment of undiscovered oil and gas resources in the Upper Cretaceous Austin Chalk and Tokio and Eutaw Formations, U.S. Gulf Coast, 2019
Assessment of undiscovered oil and gas resources in the Mancos-Menefee composite and underlying Todilto Total Petroleum Systems of the San Juan Basin Province, New Mexico and Colorado, 2020
Assessment of undiscovered gas resources in the Lewis Shale Total Petroleum System of the San Juan Basin Province, New Mexico and Colorado, 2020
Assessment of undiscovered gas resources of the Fruitland Total Petroleum System, San Juan Basin Province, New Mexico and Colorado, 2020
Assessment of undiscovered gas resources of the Sacramento Basin Province in California, 2019
Steps taken for calculating estimated ultimate recoveries of wells in the Eagle Ford Group and associated Cenomanian–Turonian strata, U.S. Gulf Coast, Texas, 2018
Assessment of continuous oil and gas resources in the Ordovician Collingwood Formation and Utica Shale of the Michigan Basin Province, 2019
Below are datasets related to the National Oil and Gas Assessments.
Below are news stories associated with this project.
Below are FAQ associated with this project.
Below are partners associated with this project.
USGS Energy Resources Program provides periodic assessments of the oil and natural gas endowment of the United States and the World. This website provides access to new, prioritized, assessment results and supporting data for the United States, as part of the Energy Policy and Conservation Act (EPCA).
Assessment Overview
![Image shows a map of the assessment units of the 2018 Delaware Basin oil and gas assessment](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/info_block/public/thumbnails/image/Map%202.jpg?itok=Hqf7Zpca)
The USGS assesses potential for undiscovered oil and gas resources in priority geologic provinces in the United States. This website highlights conventional and unconventional (continuous) oil and gas assessments.
Recent Assessments
Below are the latest US Assessments:
National Oil and Gas Assessment Methodology
The U.S. Geological Survey Energy Resources Program assesses the potential for undiscovered oil and gas resources in priority geologic provinces in the United States and around the world (click here for information about World Oil and Gas Assessments). Two methodologies are used by the USGS; one for assessing conventional oil and gas resources and one for assessing unconventional (continuous) oil and gas resources (such as shale gas and coalbed gas). USGS publications detailing and explaining the conventional and continuous assessment methodologies are provided below. These methodologies have been subjected to rigorous peer reviews by non federal panels, and the two panel reports are provided on this page.
Conventional Resources
USGS Reports
U.S. Geological Survey Assessment Concepts for Conventional Petroleum Accumulations
By James W. Schmoker and T.R. Klett
U.S. Geological Survey Input-Data Form and Operational Procedure for the Assessment of Conventional Petroleum Accumulations
By T.R. Klett, James W. Schmoker, and Ronald R. Charpentier
A Monte Carlo Simulation Method for the Assessment of Undiscovered, Conventional Oil and Gas
By Ronald R. Charpentier and T.R. Klett
Continuous Resources
USGS Reports
U.S. Geological Survey Assessment Concepts for Continuous Petroleum Accumulations
By James W. Schmoker
U.S. Geological Survey Input-Data Form and Operational Procedure for the Assessment Of Continuous Petroleum Accumulations, 2002
By T.R. Klett and James W. Schmoker
Analytic Resource Assessment Method for Continuous Petroleum Accumulations—The ACCESS Assessment Method
By Robert A. Crovelli
FORSPAN Model Users Guide
By T.R. Klett, and Ronald R. Charpentier
Methodology Revisions
Improved USGS methodology for assessing continuous petroleum resources.
Charpentier, R.R., and Cook, T.A.
Applying Probabilistic Well-Performance Parameters to Assessments of Shale-Gas Resources
By Ronald R. Charpentier and Troy Cook
Assembling Probabilistic Performance Parameters of Shale-Gas Wells
By Cook, Troy, and Charpentier, R.R.
USGS Methodology for Assessing Continuous Petroleum Resources
By Ronald R. Charpentier and Troy Cook
New U.S. Geological Survey Method for the Assessment of Reserve Growth
By Timothy R. Klett, Emil D. Attanasi, Ronald R. Charpentier, Troy A. Cook, Philip A. Freeman, Donald L. Gautier, Phuong A. Le, Robert T. Ryder, Christopher J. Schenk, Marilyn E. Tennyson, and Mahendra K. Verma (Reserve Growth Assessment Team)
Variability of Distributions of Well-Scale Estimated Ultimate Recovery for Continuous (Unconventional) Oil and Gas Resources in the United States
By U.S. Geological Survey Oil and Gas Assessment Team
Peer Review
Reserve Growth Methodology
USGS Reports
New U.S. Geological Survey Method for the Assessment of Reserve Growth
By Reserve Growth Assessment Team
Reserve Growth of Oil and Gas Fields - Investigations and Applications
By Troy Cook
Peer Review
Below are a list of recent assessment areas. You can also use the National Oil and Gas Assessment Map to browse these assessments.
Cincinnati Arch Oil and Gas Assessments
Southern Oklahoma Oil and Gas Assessments
Nemaha Uplift Province Oil and Gas Assessment
Forest City Basin Oil and Gas Assessments
Sedgwick Basin Oil and Gas Assessments
Ozark Uplift Oil and Gas Assessments
Iowa Shelf Oil and Gas Assessments
Cambridge Arch-Central Kansas Uplift Oil and Gas Assessment
Marathon Thrust Belt Oil and Gas Assessments
Superior Oil and Gas Assessments
Palo Duro Basin Oil and Gas Assessments
Sioux Arch Oil and Gas Assessments
Below are datasets related to the National Oil and Gas Assessments.
Total organic carbon and pyrolysis analysis data for the Rock Well Petroleum core #8, southern Casper arch, Natrona County, Wyoming
USGS National and Global Oil and Gas Assessment Project-U.S. Gulf Coast, Deep Tuscaloosa Conventional Gas: Assessment Unit Boundary, Assessment Input Data, and Fact Sheet Data Tables
Aggregated Oil and Natural Gas Drilling and Production History of the United States (ver. 1.1, April 2023)
USGS National and Global Oil and Gas Assessment Project-Montana Thrust Belt Province: Assessment Unit Boundaries, Assessment Input Data, and Fact Sheet Data Tables
USGS National and Global Oil and Gas Assessment Project - Resource Allocations for the BLM Carlsbad Planning Area
USGS National and Global Oil and Gas Assessment Project - Williston Basin, Bakken and Three Forks Formations Continuous Assessment Unit Boundaries and Assessment Input Data Forms
Total organic carbon and pyrolysis analysis data for the U.S. Geological Survey Alcova AR-1-13 core hole, Natrona County, Wyoming
USGS National and Global Oil and Gas Assessment Project - Williston Basin, Lower Paleozoic Conventional Assessment Unit Boundaries and Assessment Input Data Forms
USGS National and Global Oil and Gas Assessment Project - Williston Basin, Tyler Formation Assessment Unit Boundaries and Assessment Input Data Forms
USGS National and Global Oil and Gas Assessment Project - Williston Basin, Upper Paleozoic Conventional Assessment Unit Boundaries and Assessment Input Data Forms
USGS National and Global Oil and Gas Assessment Project - Williston Basin, Gas Assessment Unit Boundaries and Assessment Input Data Forms
USGS National and Global Oil and Gas Assessment Project - Northern Alaska Province, Western North Slope Assessment Unit Boundaries and Assessment Input Data Forms
Below are publications associated with this project.
Assessment of undiscovered gas resources in Upper Devonian to Lower Cretaceous strata of the western North Slope, Alaska, 2021
Assessment of continuous gas resources in the Horn River Basin, Cordova Embayment, and Liard Basin, Canada, 2019
Assessment of continuous oil and gas resources in the Mowry Shale, Wind River Basin Province, Wyoming, 2020
Geologic assessment of undiscovered oil and gas resources in the Cherokee Platform area of Kansas, Oklahoma, and Missouri
Structure contour and isopach maps of the Wolfcamp shale and Bone Spring Formation of the Delaware Basin, Permian Basin Province, New Mexico and Texas
Assessment of undiscovered oil and gas resources in the Upper Cretaceous Austin Chalk and Tokio and Eutaw Formations, U.S. Gulf Coast, 2019
Assessment of undiscovered oil and gas resources in the Mancos-Menefee composite and underlying Todilto Total Petroleum Systems of the San Juan Basin Province, New Mexico and Colorado, 2020
Assessment of undiscovered gas resources in the Lewis Shale Total Petroleum System of the San Juan Basin Province, New Mexico and Colorado, 2020
Assessment of undiscovered gas resources of the Fruitland Total Petroleum System, San Juan Basin Province, New Mexico and Colorado, 2020
Assessment of undiscovered gas resources of the Sacramento Basin Province in California, 2019
Steps taken for calculating estimated ultimate recoveries of wells in the Eagle Ford Group and associated Cenomanian–Turonian strata, U.S. Gulf Coast, Texas, 2018
Assessment of continuous oil and gas resources in the Ordovician Collingwood Formation and Utica Shale of the Michigan Basin Province, 2019
Below are datasets related to the National Oil and Gas Assessments.
Below are news stories associated with this project.
Below are FAQ associated with this project.
Below are partners associated with this project.