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
click here to launchAssessment Overview
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.
Summary of Continuous Assessments
This applications shows maps and tables of all continuous assessments in the United States.
Click here to launchRecent Assessments
Below are the latest US Assessments:
2019 Mississippian Delle Phosphatic Member of the Woodman Formation
2019 Permian Phosphoria Formation of the Southwestern WY Province
2019 Appalachian Basin Province
2018 Eastern Great Basin Province
2018 Uinta-Piceance Basin/Tight-Gas of Mesaverde and Wasatch
Browse AssessmentsScience Center Objects
USGS Energy Resources Program provides periodic assessments of the oil and natural gas endowment of the United States and the World (click here for information about World Oil and Gas Assessments). 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).
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. 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
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Date published: December 19, 2018Status: ActiveEastern Basins Oil and Gas Assessments
The USGS has conducted several assessments of undiscovered oil and gas in formations in the Blue Ridge Thrust Belt (5068), Piedmont Province (5069), Atlantic Coastal Plain Province (5070), and the New England Province (5072). These basins are generally east of the Appalachian Basin...
Contacts: Christopher J Schenk -
Date published: December 7, 2018Status: ActiveCincinnati Arch Oil and Gas Assessments
The U.S. Geological Survey completed the following assessments of undiscovered oil and gas resources of the Cincinnati Arch Province (5066) :
- 1995 Assessment (DDS-30).
Contacts: Christopher J Schenk -
Date published: December 7, 2018Status: ActiveArkoma Basin Oil and Gas Assessments
The U.S. Geological Survey completed the following assessments of undiscovered oil and gas resources of the Arkoma Basin Province 5062:
- 2010 Continuous and Conventional Assessment (Fact Sheet 2010-3043).
- 1995 Assessment (DDS-30). ...
Contacts: Christopher J Schenk -
Date published: December 7, 2018Status: ActiveSouthern Oklahoma Oil and Gas Assessments
The U.S. Geological Survey completed the following assessments of undiscovered continuous oil and gas resources of the Southern Oklahoma Province (5061):
- 1995 Assessment (DDS-30).
Contacts: Christopher J Schenk -
Date published: December 7, 2018Status: ActiveSedgwick Basin Oil and Gas Assessments
Province Code: 5059
The Salina Basin Province (5059), covers an area of about 45,000 sq mi, consisting of the eastern half of Nebraska and the north-central portion of Kansas. The basin lies between the Cambridge Arch-Central Kansas Uplift Province (5053) on the west, the Nemaha Uplift Province (5055) to the east, the Sioux Arch Province (5032) to the north, and a...
Contacts: Christopher J Schenk -
Date published: December 7, 2018Status: ActiveOzark Uplift Oil and Gas Assessments
The U.S. Geological Survey completed the following assessments of undiscovered oil and gas potential of the Ozark Uplift Province (5057):
- 1995 Assessment (DDS 30)
Contacts: Christopher J Schenk -
Date published: December 7, 2018Status: ActiveNemaha Uplift Province Oil and Gas Assessment
The U.S. Geological Survey completed the following assessments of undiscovered oil and gas potential of the Nemaha Uplift Province (5055):
- 1995 Assessment (DDS 30)
Contacts: Christopher J Schenk -
Date published: December 7, 2018Status: ArchivedForest City Basin Oil and Gas Assessments
The U.S. Geological Survey completed the following assessments of undiscovered oil and gas potential of the Forest City Basin Province (5056):
- 1995 Assessment (DDS 30)
Contacts: Christopher J Schenk -
Date published: December 7, 2018Status: ActiveCambridge Arch-Central Kansas Uplift Oil and Gas Assessment
The U.S. Geological Survey completed the following assessments of undiscovered oil and gas potential of the Cambridge Arch/Central Kansas Uplift Province (5053):
- 1995 Assessment (DDS 30)
Contacts: Christopher J Schenk -
Date published: December 7, 2018Status: ActiveIowa Shelf Oil and Gas Assessments
The U.S. Geological Survey completed the following assessments of undiscovered oil and gas potential of the Iowa Shelf Province (5052):
- 1995 Assessment (DDS 30)
Contacts: Christopher J Schenk
Lithologic descriptions, geophysical logs, and source-rock geochemistry of the U.S. Geological Survey Alcova Reservoir AR–1–13 Core Hole, Natrona County, Wyoming
In 2013, a continuous 624-foot core hole was drilled and logged by the U.S. Geological Survey in Natrona County, Wyoming, with the goal to better understand Cretaceous source rocks in the Wind River Basin. The core hole, named the Alcova Reservoir AR–1–13, penetrated the interval extending from the upper part of the Lower Cretaceous Cloverly...
Kirschbaum, Mark A.; Finn, Thomas M.; Schenk, Christopher J.; Hawkins, Sarah J.
Assessment of continuous oil and gas resources in the Mississippian Delle Phosphatic Member of the Woodman Formation in the Eastern Great Basin Province of Nevada, Utah, and Idaho, 2019
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 144 million barrels of shale oil and 559 billion cubic feet of shale gas in the Mississippian Delle Phosphatic Member of the Woodman Formation in the Eastern Great Basin Province of Nevada, Utah, and Idaho.
Schenk, Christopher J.; Mercier, Tracey J.; Finn, Thomas M.; Marra, Kristen R.; Le, Phuong A.; Brownfield, Michael E.; Leathers-Miller, Heidi M.
Assessment of continuous gas resources in the Permian Phosphoria Formation of the Southwestern Wyoming Province, Wyoming, 2019
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 1.4 trillion cubic feet of continuous gas in the Phosphoria Formation of the Southwestern Wyoming Province, Wyoming.
Schenk, Christopher J.; Mercier, Tracey J.; Finn, Thomas M.; Marra, Kristen R.; Le, Phuong A.; Leathers-Miller, Heidi M.; Pitman, Janet K.; Brownfield, Michael E.; Drake, Ronald M.
Assessment of undiscovered continuous oil and gas resources in the Upper Ordovician Point Pleasant Formation and Utica Shale of the Appalachian Basin Province, 2019
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable continuous mean resources of 1.8 billion barrels of oil and 117.2 trillion cubic feet of gas in the Upper Ordovician Point Pleasant Formation and Utica Shale of the Appalachian Basin Province.
Enomoto, Catherine B.; Trippi, Michael H.; Higley, Debra K.; Drake, Ronald M.; Gaswirth, Stephanie B.; Mercier, Tracey J.; Brownfield, Michael E.; Leathers-Miller, Heidi M.; Le, Phuong A.; Marra, Kristen R.; Tennyson, Marilyn E.; Woodall, Cheryl A.; Schenk, Christopher J.
Assessment of undiscovered gas resources in the Middle Devonian Marcellus Shale of the Appalachian Basin Province, 2019
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable continuous mean resources of 96.5 trillion cubic feet of gas in the Middle Devonian Marcellus Shale of the Appalachian Basin Province.
Higley, Debra K.; Enomoto, Catherine E; Leathers-Miller, Heidi M.; Ellis, Geoffrey S.; Mercier, Tracey J.; Schenk, Christopher J.; Trippi, Michael H.; Le, Phuong A.; Brownfield, Michael E.; Woodall, Cheryl A.; Marra, Kristen R.; Tennyson, Marilyn E.
Assessment of continuous oil resources in the Eastern Great Basin Province of Nevada, Utah, and Idaho, 2018
The U.S. Geological Survey (USGS) quantitatively assessed the potential for undiscovered, technically recoverable continuous oil and gas resources in the Eastern Great Basin Province (Anna and others, 2007) of Nevada, Utah, and Idaho (fig. 1). The assessment focused on the area of the province between the Roberts Mountains and...
Schenk, Christopher J.; Mercier, Tracey J.; Woodall, Cheryl A.; Finn, Thomas M.; Gaswirth, Stephanie B.; Marra, Kristen R.; Le, Phuong A.; Brownfield, Michael E.; Leathers-Miller, Heidi M.; Drake, Ronald M.; Kinney, Scott A.
Assessment of undiscovered continuous tight-gas resources in the Mesaverde Group and Wasatch Formation, Uinta-Piceance Province, Utah and Colorado, 2018
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 24 trillion cubic feet of gas in the Mesaverde Group and Wasatch Formation of the Uinta-Piceance Province in northeast Utah and northwest Colorado.
Drake, Ronald M.; Schenk, Christopher J.; Mercier, Tracey J.; Le, Phuong A.; Finn, Thomas M.; Johnson, Ronald C.; Woodall, Cheryl A.; Gaswirth, Stephanie B.; Marra, Kristen R.; Pitman, Janet K.; Leathers-Miller, Heidi M.; Haines, Seth S.; Tennyson, Marilyn E.
Structure contour and overburden maps of the Niobrara interval of the Upper Cretaceous Cody Shale in the Wind River Basin, Wyoming
The Wind River Basin in central Wyoming is one of many structural and sedimentary basins that formed in the Rocky Mountain foreland during the Laramide orogeny. The basin is bounded by the Washakie, Owl Creek, and southern Bighorn uplifts on the north, the Casper arch on the east, the Granite Mountains uplift on the south, and Wind...
Finn, Thomas M.
Stratigraphic cross sections of the Niobrara Interval of the Upper Cretaceous Cody Shale in the Bighorn Basin, Wyoming and Montana
The Bighorn Basin is one of many structural and sedimentary basins that formed in the Rocky Mountain foreland during the Laramide orogeny. The basin is nearly 180 miles long, 100 miles wide, and encompasses about 10,400 square miles in northern Wyoming and southern Montana. The basin is bounded by major basement uplifts that include the Pryor...
Finn, Thomas M.
Assessment of undiscovered oil and gas resources in the South Florida basin, 2016
Using a geology-based assessment methodology, the U.S. Geological Survey estimated mean undiscovered, technically recoverable resources of 49 million barrels of oil and 18 billion cubic feet of gas in the onshore and State waters part of the South Florida basin.
Roberts-Ashby, Tina L.; Hackley, Paul C.; Lohr, Celeste D.; Schenk, Christopher J.; Mercier, Tracey J.; Whidden, Katherine J.; Le, Phuong A.; Tennyson, Marilyn E.; Gaswirth, Stephanie B.; Woodall, Cheryl A.; Brownfield, Michael E.; Leathers-Miller, Heidi M.; Marra, Kristen R.; Finn, Thomas M.
Assessment of continuous oil and gas resources in the Niobrara interval of the Cody Shale, Wind River Basin Province, Wyoming, 2018
Using a geology-based assessment methodology, the U.S. Geological Survey estimated means of 528 million barrels of oil and 2 trillion cubic feet of gas in the Niobrara interval of the Cody Shale in the Wind River Basin Province, Wyoming.
Finn, Thomas M.; Schenk, Christopher J.; Mercier, Tracey J.; Tennyson, Marilyn E.; Le, Phuong A.; Brownfield, Michael E.; Marra, Kristen R.; Leathers-Miller, Heidi M.; Drake, Ronald M.; Woodall, Cheryl A.; Kinney, Scott A.
Assessment of undiscovered continuous oil and gas resources in the Wolfcamp Shale and Bone Spring Formation of the Delaware Basin, Permian Basin Province, New Mexico and Texas, 2018
Using a geology-based assessment methodology, the U.S. Geological Survey assessed undiscovered, technically recoverable continuous mean resources of 46.3 billion barrels of oil and 281 trillion cubic feet of gas in the Wolfcamp shale and Bone Spring Formation of the Delaware Basin in the Permian Basin Province, southeast New Mexico and west Texas.
Gaswirth, Stephanie B.; French, Katherine L.; Pitman, Janet K.; Marra, Kristen R.; Mercier, Tracey J.; Leathers-Miller, Heidi M.; Schenk, Christopher J.; Tennyson, Marilyn E.; Woodall, Cheryl A.; Brownfield, Michael E.; Finn, Thomas M.; Le, Phuong A.-
Date published: March 25, 2019Downloadable Data for National Oil and Gas Assessments
GIS Data for the National Oil and Gas Assessments
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Date published: December 26, 2019Total organic carbon and pyrolysis analysis data for the U.S. Geological Survey Alcova AR-1-13 core hole, Natrona County, Wyoming
In 2013 the U.S. Geological Survey (USGS) drilled a continuous core in the southeastern part of the Wind River Basin, Wyoming to evaluate the source rock potential of the Lower and lowermost Upper Cretaceous marine shales . The well, named the Alcova Reservoir AR–1–13, located on the northeast flank of the Alcova anticline was spud in the lower part of the Frontier Form
Attribution: Central Energy Resources Science Center -
Date published: October 16, 2019
USGS National and Global Oil and Gas Assessment Project - Piceance and Uinta Basins, Mesaverde Group Tight Gas Assessment Unit Boundaries and Assessment Input Data Forms
This data release contains the boundaries of assessment of undiscovered continuous tight-gas resources in the Mesaverde Group and Wasatch Formation, Uinta-Piceance Province, Utah and Colorado. The Assessment Unit is the fundamental unit used in the National Assessment Project for the assessment of undiscovered oil and gas resources. The Assessment Unit is defined within the context of the h...
Attribution: Central Energy Resources Science Center -
Date published: October 16, 2019
USGS National and Global Oil and Gas Assessment Project-Bighorn Basin Province, Niobrara Formation Assessment Units and Input Data Forms
This data release contains the boundaries of assessment units and input data for the assessment of continuous oil and gas resources of the Niobrara interval of the Cody Shale in the Bighorn Basin Province of Wyoming and Montana. The Assessment Unit is the fundamental unit used in the National Assessment Project for the assessment of undiscovered oil and gas resources. The Assessment Unit is...
Attribution: Central Energy Resources Science Center -
Date published: October 2, 2019
USGS National and Global Oil and Gas Assessment Project - Appalachian Basin Province, Middle Devonian Marcellus Shale Assessment Units and Input Data Forms
This data release contains the boundaries of assessment units and input data for the assessment of undiscovered gas resources in the Middle Devonian Marcellus Shale of the Appalachian Basin Province, 2019. The Assessment Unit is the fundamental unit used in the National Assessment Project for the assessment of undiscovered oil and gas resources. The Assessment Unit is defined within the...
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Date published: October 2, 2019
USGS National and Global Oil and Gas Assessment Project - Appalachian Basin Province, Point Pleasant Formation and Utica Shale Assessment Unit Boundaries and Assessment Input Data Forms
This data release contains the boundaries of assessment units and input data for the assessment of undiscovered gas hydrate resources on the north slope of Alaska. The Assessment Unit is the fundamental unit used in the National Assessment Project for the assessment of undiscovered oil and gas resources. The Assessment Unit is defined within the context of the higher-level Total Petroleum...
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Date published: August 21, 2019
USGS Gulf Coast Petroleum Systems, and National and Global Oil and Gas Assessment Projects-Eagle Ford Group and Associated Cenomanian-Turonian Strata Assessment Unit Boundaries and Assessment Input Data Forms
This data release contains the boundaries of assessment units and input data for the assessment of undiscovered oil and gas in the Eagle Ford group and Associated Cenomanian-Turonian Strata, Texas Gulf Coast. The Assessment Unit is the fundamental unit used in the National Assessment Project for the assessment of undiscovered oil and gas resources. The Assessment Unit is defined within the...
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Date published: March 14, 2019
USGS National and Global Oil and Gas Assessment Project - Permian Basin Province, Midland Basin, Wolfcamp Shale Assessment Unit Boundaries and Assessment Input Data Forms, Version 2.0
The Assessment Unit is the fundamental unit used in the National Assessment Project for the assessment of undiscovered oil and gas resources. The Assessment Unit is defined within the context of the higher-level Total Petroleum System. The Assessment Unit is shown herein as a geographic boundary interpreted, defined, and mapped by the geologist responsible for the province and incorporates...
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Date published: January 1, 2019
USGS Gulf Coast Petroleum Systems, and National and Global Oil and Gas Assessment Projects - USGS Province 50 Assessment Unit Boundaries and Assessment Input Forms
The Assessment Unit is the fundamental unit used in the National Assessment Project for the assessment of undiscovered oil and gas resources. The Assessment Unit is defined within the context of the higher-level Total Petroleum System. The Assessment Unit is shown herein as a geographic boundary interpreted, defined, and mapped by the geologist responsible for the province and incorporates...
Attribution: Florence Bascom Geoscience Center -
Date published: January 1, 2019
USGS National and Global Oil and Gas Assessment Project-Ventura Basin Province, Monterey Formation Assessment Units Boundaries
The Assessment Unit is the fundamental unit used in the National Assessment Project for the assessment of undiscovered oil and gas resources. The Assessment Unit is defined within the context of the higher-level Total Petroleum System. The Assessment Unit is shown herein as a geographic boundary interpreted, defined, and mapped by the geologist responsible for the province and incorporates...
Attribution: Central Energy Resources Science Center -
Date published: January 1, 2019
USGS National and Global Oil and Gas Assessment Project-San Joaquin Basin Province, Monterey Formation Assessment Unit Boundaries
The Assessment Unit is the fundamental unit used in the National Assessment Project for the assessment of undiscovered oil and gas resources. The Assessment Unit is defined within the context of the higher-level Total Petroleum System. The Assessment Unit is shown herein as a geographic boundary interpreted, defined, and mapped by the geologist responsible for the province and incorporates...
Attribution: Central Energy Resources Science Center
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Date published: March 19, 2019Explore US Oil and Gas Assessments
This map shows the provinces assessed by the USGS for undiscovered oil and gas resources.
Attribution: Energy Resources Program, Region 11: Alaska, States and Territories, Region 3: Great Lakes, Region 5: Missouri Basin, Region 6: Arkansas-Rio Grande-Texas-Gulf, Region 9: Columbia-Pacific Northwest, Region 2: South Atlantic-Gulf (Includes Puerto Rico and the U.S. Virgin Islands), Region 4: Mississippi Basin, Region 7: Upper Colorado Basin, Region 12: Pacific Islands (American Samoa, Hawaii, Guam, Commonwealth of the Northern Mariana Islands), Central Energy Resources Science Center, Eastern Energy Resources Science Center
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Date published: November 28, 2018USGS Announces Largest Continuous Oil Assessment in Texas and New Mexico
Estimates Include 46.3 Billion Barrels of Oil, 281 Trillion Cubic feet of Natural Gas, and 20 Billion Barrels of Natural Gas Liquids in Texas and New Mexico’s Wolfcamp Shale and Bone Spring Formation.
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Date published: June 22, 2018USGS Estimates Oil and Gas in Texas’ Eagle Ford Group
The Eagle Ford Group of Texas contains estimated means of 8.5 billion barrels of oil, 66 trillion cubic feet of natural gas, and 1.9 billion barrels of natural gas liquids, according to a new assessment by the U.S. Geological Survey. This estimate consists of undiscovered, technically recoverable resources in continuous accumulations.
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Date published: April 10, 2008
3 to 4.3 Billion Barrels of Technically Recoverable Oil Assessed in North Dakota and Montana’s Bakken Formation—25 Times More Than 1995 Estimate—
North Dakota and Montana have an estimated 3.0 to 4.3 billion barrels of undiscovered, technically recoverable oil in an area known as the Bakken Formation.
Attribution: States and Territories, Region 5: Missouri Basin
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What are the different columns on a USGS oil and gas resource assessment table?
The USGS uses a statistically-based process to calculate the likely range of its estimate. The range of values extends from a 5% or greater likelihood of occurrence (the F5 value, or largest estimated value) to less than 95% likelihood of occurrence (the F95 value, or smallest estimated value). The F50 column is the value that occurs when 50% of... -
Why have some estimates of undiscovered technically recoverable oil or gas changed so much from previous estimates?
Petroleum geologists have long known that oil and gas resources were present in “tight” or impermeable formations such as shale. But there was no feasible way to extract that oil and gas, so they were not “technically recoverable” and were not included in USGS assessment results. Thanks to new technologies, oil and gas can now be extracted from “... -
Where in the United States is hydraulic fracturing being used for oil and gas extraction?
Hydraulic fracturing is used in many established oil and gas producing regions of the country as well as some areas new to the petroleum industry. Maps of major shale gas, tight gas, and tight oil basins are available from the U.S. Energy Information Administration, although not all of the shale basins shown currently have production. -
When did hydraulic fracturing become such a popular approach to oil and gas production?
Hydraulic fracturing in vertical wells has been used for over fifty years to improve the flow of oil and gas from conventional reservoirs. However, the current practice of horizontal drilling coupled with multiple applications of hydraulic fracturing in a single well was pioneered in the late 1980s and has continued to evolve. Since the final... -
Are other countries using hydraulic fracturing for oil and gas extraction?
Yes, hydraulic fracturing is being used extensively in Canada and is increasingly being used in countries in Asia, Europe, and South America. -
What are "technically recoverable" oil and gas resources?
“Technically recoverable” means that the oil and/or gas can be produced using currently available technology and industry practices. This is regardless of any economic or accessibility considerations. For example, the technology required to produce oil from a location might exist, but it costs more than the oil is worth. The oil is still...