U.S. Department of the Interior

U.S. Geological Survey

Digital Data Series 69–MM

National and Global Petroleum Assessment

U.S. Geological Survey Assessments of Continuous 

(Unconventional) Oil and Gas Resources, 2000 to 2011
Cover: Dipping beds of the Mowry Shale at the east end of Irish Canyon, Colorado. Photo by Christopher J. Schenk, June 7, 2004.
U.S. Geological Survey Assessments of 

Continuous (Unconventional) Oil and Gas 

Resources, 2000 to 2011

By U.S. Geological Survey U.S. Continuous Resources Assessment Team

National and Global Petroleum Assessment

Digital Data Series 69–MM

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2015

For more information on the USGS—the Federal source for science about the Earth, its natural and living 

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Suggested citation:

U.S. Geological Survey U.S. Continuous Resources Assessment Team, 2015, U.S. Geological Survey assessments of 

continuous (unconventional) oil and gas resources, 2000 to 2011: U.S. Geological Survey Digital Data Series DDS-69-MM, 

46 p., http://dx.doi.org/10.3133/ds69MM.

ISSN 2327-638X (online)

ISSN 2333-0481 (CD/DVD)
iii

Members of U.S. Geological Survey U.S. Continuous 

Resources Assessment Team

Lawrence O. Anna

Michael E. Brownfield

Ronald R. Charpentier

James L. Coleman

Steven M. Condon

Troy A. Cook

Russell F. Dubiel

Thaddeus S. Dyman

Thomas M. Finn

Romeo M. Flores

Paul C. Hackley

Joseph R. Hatch

Mitchell E. Henry

Timothy C. Hester

Robert D. Hettinger

Debra K. Higley

David W. Houseknecht

Ronald C. Johnson

Mark A. Kirschbaum

Timothy R. Klett

Robert C. Milici

Philip H. Nelson

Mark J. Pawlewicz

Krystal M. Pearson

Ofori N. Pearson

Janet K. Pitman

Richard M. Pollastro

Jennie L. Ridgley

Laura N.R. Roberts

Stephen B. Roberts

William A. Rouse

Robert T. Ryder

Christopher J. Schenk

Richard G. Stanley

Christopher S. Swezey

Marilyn E. Tennyson

Peter D. Warwick

v

Contents

Members of U.S. Geological Survey U.S. Continuous Resources Assessment Team ......................iii

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Data Resources..............................................................................................................................................1

Input Form and Calculation Program Versions ................................................................................2

Corrections.............................................................................................................................................2

Use as Analogs......................................................................................................................................2

References Cited..........................................................................................................................................26

Appendix 1. Publications Presenting Results of Assessments Used in this Report .....................27

CD-ROMs..............................................................................................................................................27

Fact Sheets ..........................................................................................................................................28

Appendix 2. Structure of the Files Presented in this Report .............................................................31

Figures

1. Cloud plot for estimated area of cells (drainage areas) in United States 

shale-gas assessment units .......................................................................................................3

2. Cloud plot for estimated area of cells (drainage areas) in United States 

coalbed-gas assessment units...................................................................................................4

3. Cloud plot for estimated area of cells (drainage areas) in United States 

tight-gas assessment units .........................................................................................................5

4. Cloud plot for estimated area of cells (drainage areas) in United States 

continuous-oil assessment units ...............................................................................................6

5. Cloud plot for estimated percent of untested area in sweet spots in 

United States shale-gas assessment units ..............................................................................7

6. Cloud plot for estimated percent of untested area in sweet spots in 

United States coalbed-gas assessment units .........................................................................8

7. Cloud plot for estimated percent of untested area in sweet spots in 

United States tight-gas assessment units................................................................................9

8. Cloud plot for estimated percent of untested area in sweet spots in 

United States continuous-oil assessment units ....................................................................10

9. Cloud plot for EURs in United States shale-gas assessment units ....................................11

10. Cloud plot for EURs in United States coalbed-gas assessment units................................12

11. Cloud plot for EURs in United States tight-gas assessment units ......................................13

12. Cloud plot for EURs in United States continuous-oil assessment units ............................14
vi

Tables

1. List of files included in this report..............................................................................................1

2. Input data for estimated area of cells (drainage areas) for United States 

shale-gas assessment units, values in acres ........................................................................15

3. Input data for estimated area of cells (drainage areas) for United States 

coalbed-gas assessment units, values in acres ...................................................................16

4. Input data for estimated area of cells (drainage areas) for United States 

tight-gas assessment units, values in acres..........................................................................17

5. Input data for estimated area of cells (drainage areas) for United States 

continuous-oil assessment units, values in acres ................................................................18

6. Input data for estimated percent of untested area in sweet spots for 

United States shale-gas assessment units ............................................................................19

7. Input data for estimated percent of untested area in sweet spots for 

United States coalbed-gas assessment units .......................................................................20

8. Input data for estimated percent of untested area in sweet spots for 

United States tight-gas assessment units..............................................................................21

9. Input data for estimated percent of untested area in sweet spots for 

United States continuous-oil assessment units ....................................................................22

10. Input data for estimated ultimate recovery distributions for United States 

shale-gas assessment units, values in billions of cubic feet of natural gas ....................22

11. Input data for estimated ultimate recovery distributions for United States 

coalbed-gas assessment units, values in billions of cubic feet of natural gas................23

12. Input data for estimated ultimate recovery distributions for United States 

tight-gas assessment units, values in billions of cubic feet of natural gas ......................24

13. Input data for estimated ultimate recovery distributions for United States 

continuous-oil assessment units, values in millions of barrels of oil.................................25
U.S. Geological Survey Assessments of Continuous 

(Unconventional) Oil and Gas Resources, 2000 to 2011

By U.S. Geological Survey U.S. Continuous Resources Assessment Team

These assessments were previously documented in 

a series of publications, the list of which is presented in 

Appendix 1. For some of the assessments, the only previous 

documentation was a summary of the results in a short USGS 

Fact Sheet. The present report provides more extensive documentation for those assessments than was previously available.

Since 2011, the USGS has continued to assess continuous 

oil and gas resources in the United States and internationally. 

These assessments, however, used a different methodology 

(Charpentier and Cook, 2010) that has been modified from the 

methodology that was used previously. None of these newer 

assessments are included in this report.

Data Resources

This report contains extensive documentation of the 

USGS assessments of continuous accumulations of oil and gas 

resources. Both the input and output information of the assessments are included. The data are in a collection of spreadsheet 

tables (table 1), in both Microsoft Excel format and tabdelimited format. Descriptions of the variables in each table 

are presented in Appendix 2.

The geographic boundaries of 184 AUs are included in 

this report as a set of GIS (geographic information system) 

files. Two AUs (50310261, the Winnipeg-Icebox Continuous 

Gas AU, and 50640561, the Elvins Shale Gas AU) did 

not have geographic boundaries established and thus are 

not included.

Abstract

From 2000 to 2011, the U.S. Geological Survey conducted 

139 quantitative assessments of continuous (unconventional) 

oil and gas accumulations within the United States. This report 

documents those assessments more fully than previously done 

by providing detailed documentation of both the assessment 

input and output. This report also compiles the data into 

spreadsheet tables that can be more readily used to provide 

analogs for future assessments, especially for hypothetical 

continuous accumulations.

Introduction

The U.S. Geological Survey (USGS) conducted 139 

quantitative assessments of oil and gas potential in continuous (unconventional) accumulations from 2000 to 2011. This 

report provides documentation of the input and output for those 

assessments in one place and in a more complete fashion than 

previously published. All of these assessments units (AUs) were 

for areas within the United States, excepting one that was an 

extension of a coalbed methane trend into northeast Mexico.

All the assessments documented in this report were 

conducted using the same quantitative methodology. The basic 

model for this methodology is explained in Schmoker (2003). 

The input form and operational procedure can be found in 

Klett and Schmoker (2003). The program itself is available 

and extensively documented in Crovelli (2012). Additional 

information is given in Klett and Charpentier (2003).

Table 1. List of files included in this report.

Microsoft Excel File Name Tab-delimited File Name Contents

Main Input.xlsx Main Input.tab Data from input forms

Ecosystem Allocations.xlsx Ecosystem Allocations.tab Allocations to ecosystem

Federal Land Allocations.xlsx Federal Land Allocations.tab Allocations to Federal agency

Land Ownership Allocations.xlsx Land Ownership Allocations.tab Allocations to land ownership category

State Allocations.xlsx State Allocations.tab Allocations to state

Continuous Results.xlsx Continuous Results.tab Assessment results

Code List.xlsx Code List.tab Main code list

Ecosystem Codes.xlsx Ecosystem Codes.tab Code list for ecosystem names

Cloud Plots.xlsx Cloud Plots.tab Data for constructing cloud plots
2 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

Input Form and Calculation Program Versions

These assessments took place over the course of more 

than a decade, and refinements to both the input form and 

calculation program were made during the same period. The 

input form was changed more frequently than the program. In 

2003, the input form was revised to accommodate the change 

in parameter inputs from median values to modal values. 

Other changes to the input form were primarily made to 

include additional ancillary variables.

The program for calculating the estimates is named 

“ACCESS,” and several versions exist (Crovelli, 2012). 

The unnumbered version, originally described in Crovelli 

(2000), was not used for any official USGS assessments. The 

first version actually used for assessments is herein termed 

“version 1,” which was used from 2000 to 2002. Version 1 

differed from the previous ACCESS version in that it included 

a variable for “Percentage of total assessment-unit area that is 

untested.” Each triangular distribution (used to describe the 

probability distribution of an input variable) was described by 

the minimum, median, and maximum values. ACCESS version 2 was used from 2003 to 2008. Each triangular distribution was described by the minimum, mode, and maximum 

values. ACCESS version 3 was used from 2009 to 2011. An 

error was identified in version 2: gas-oil ratio inputs in continuous oil AUs were set as a triangle with minimum, mode, 

and maximum as 240, 320, and 960, and the program ignored 

any other input. The error correction was the only change 

made in version 3. Because the error only affected coproduct 

volumes and only in oil AUs, there was only minor effect in a 

few assessments.

Both the input form version and the version of the program used to run the calculations (for AUs that were quantitatively assessed) are documented in Microsoft Excel and tabdelimited files named “Main Input.” File Main Input includes 

all the variables for each version of the input form. Thus, some 

variables will not be populated in file Main Input for a specific 

AU because that variable was not on the input form used in 

that assessment.

Corrections

Corrections were made to some values in the data tables. 

Some of these were minor and corrected typographical errors 

or enforced consistency in naming conventions. The list of 

codes used in these assessments is included as file “Code 

List.” Codes in the various original files were checked and 

changed for consistency where necessary.

Changes were also made to the data tables to ensure that 

allocation percentages added up correctly. The sum of the land 

ownership allocations should be 100 percent, and the sum of 

the Federal land allocations should be the percent of Federal 

land in file “Land Ownership Allocations.”

A few corrections were more significant, and these 

are highlighted in green in the Microsoft Excel versions of 

the spreadsheets. The most significant corrections are for 

those values on the original input forms that were different 

from those values actually used in the resource calculations. 

Almost all of these are a result of the error in version 2 of the 

ACCESS program, as explained above.

AUs that were defined but not quantitatively assessed are 

included in the “Main Input” and allocation-related files, but 

not in the “Continuous Results” or “Cloud Plots” files. These 

unassessed AUs are highlighted in purple in the Microsoft 

Excel versions of the spreadsheets. Although some of the original input forms for these unassessed AUs had some values 

filled in (such as allocation unit names and area percentages), 

these values were never checked as they would have been 

for a quantitative assessment. Therefore, these values are not 

included in the Main Input file. Only the header information 

for unassessed AUs is included in the Main Input file.

Use as Analogs

This report is not only intended to more fully document 

the assessments of continuous oil and gas resources, but also 

to provide the information in such a way as to facilitate its use 

as analog data for subsequent assessments. U.S. Geological 

Survey Oil and Gas Assessment Team (2012) documented the 

variability of estimated ultimate recovery (EUR) distributions 

from these assessments to provide a set of analogs for EURs. 

In that report, the data were presented in two forms: in tables 

and in graphs termed “cloud plots.” These two forms of data 

presentation are also provided herein, not only for estimated 

EUR distributions but also for estimated cell sizes and estimations of the percent of undrilled areas that would be both successful and in sweet spots.

Use of these data for analogs necessitates several cautionary statements. All the distributions are taken from the assessment input distributions. They represent the estimated distributions for undrilled portions of the AU in question. Generally, the 

distributions for undrilled portions were closely based on data 

for the drilled portions. Changes from the drilled to the undrilled 

portions could, however, result from changes in drilling/completion practice or differences in the geology between drilled and 

undrilled areas. The undrilled portions of the AU were estimated 

as if drilled using what was the current “best practice” at the 

time of the assessment. (Dates of the assessments can be found 

in the “Main Input” file.) Whereas the wells drilled prior to the 

assessment may have been a mixture of vertical and horizontal 

wells, the undrilled areas would be estimated as if drilled by 

either vertical or horizontal wells, whichever was the “best 

practice” at the time of the assessment.

The three variables most useful as analogs are EUR distributions, cell sizes, and percent of undrilled areas that would 

be both successful and in sweet spots. For each of these variables, the 139 AUs are divided into four groups by reservoir 

type (shale gas, coalbed gas, tight gas, and continuous oil). 

Twelve cloud plots (figs. 1 to 12) and 12 tables (tables 2 to 13) 

summarizing these data are provided in the next sections of 

this report. The data for the plots are in the Cloud Plots file in 

the Excel folder of the online downloads directory.
Figures 3

Figure 1. Cloud plot for estimated area of cells (drainage areas) in United States shale-gas assessment units. Each curve represents 

one assessment unit and is based on the input data in table 2. Black diamonds show the mean value for each curve.

10

100

1,000 Cell size, in acres

Cell Sizes—Shale Gas 

Fractile, in percent

100 90 80 70 60 50 40 30 20 10 0

 
4 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

10

100

1,000 Cell size, in acres

Cell Sizes—Coalbed Gas 

Fractile, in percent

100 90 80 70 60 50 40 30 20 10 0

Figure 2. Cloud plot for estimated area of cells (drainage areas) in United States coalbed-gas assessment units. Each curve represents

one assessment unit and is based on the input data in table 3. Black diamonds show the mean value for each curve.
Figures 5

10

100

1,000

Cell size, in acres

Cell Sizes—Tight Gas 

Fractile, in percent

100 90 80 70 60 50 40 30 20 10 0

Figure 3. Cloud plot for estimated area of cells (drainage areas) in United States tight-gas assessment units. Each curve represents 

one assessment unit and is based on the input data in table 4. Black diamonds show the mean value for each curve.
6 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

10

100

1,000

Cell size, in acres

Cell Sizes—Continuous Oil 

Fractile, in percent

100 90 80 70 60 50 40 30 20 10 0

Figure 4. Cloud plot for estimated area of cells (drainage areas) in United States continuous-oil assessment units. Each curve represents

one assessment unit and is based on the input data in table 5. Black diamonds show the mean value for each curve.
Figures 7

50

40

30

20

10

80

90

100

70

60

Percent of untested area in sweet spots

Sweet Spot Percent—Shale Gas

Fractile, in percent

100 90 80 70 60 50 40 30 20 10 0

0

Figure 5. Cloud plot for estimated percent of untested area in sweet spots in United States shale-gas assessment units. Each curve 

represents one assessment unit and is based on the input data in table 6. Black diamonds show the mean value for each curve.
8 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

50

40

30

20

10

80

90

100

70

60

Percent of untested area in sweet spots

Sweet Spot Percent—Coalbed Gas

Fractile, in percent

100 90 80 70 60 50 40 30 20 10 0

0

Figure 6. Cloud plot for estimated percent of untested area in sweet spots in United States coalbed-gas assessment units. Each 

curve represents one assessment unit and is based on the input data in table 7. Black diamonds show the mean value for each curve.
Figures 9

50

40

30

20

10

80

90

100

70

60

Percent of untested area in sweet spots

Sweet Spot Percent—Tight Gas

Fractile, in percent

100 90 80 70 60 50 40 30 20 10 0

0

Figure 7. Cloud plot for estimated percent of untested area in sweet spots in United States tight-gas assessment units. Each curve 

represents one assessment unit and is based on the input data in table 8. Black diamonds show the mean value for each curve.
10 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

50

40

30

20

10

80

90

100

70

60

Percent of untested area in sweet spots

Sweet Spot Percent—Continuous Oil

Fractile, in percent

100 90 80 70 60 50 40 30 20 10 0

0

Figure 8. Cloud plot for estimated percent of untested area in sweet spots in United States continuous-oil assessment units. Each

curve represents one assessment unit and is based on the input data in table 9. Black diamonds show the mean value for each curve.
Figures 11

1

0.1

100

10

Estimated ultimate recovery (BCFG)

EUR—Shale Gas

Fractile, in percent

100 90 80 70 60 50 40 30 20 10 0

0.01

Figure 9. Cloud plot for EURs in United States shale-gas assessment units. Each curve represents one assessment unit and is 

based on the input data in table 10. Black diamonds show the mean value for each curve. [EUR, estimated ultimate recovery; BCFG, 

billions of cubic feet of gas]
12 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

1

0.1

100

10

Estimated ultimate recovery (BCFG)

EUR—Coalbed Gas

Fractile, in percent

100 90 80 70 60 50 40 30 20 10 0

0.01

Figure 10. Cloud plot for EURs in United States coalbed-gas assessment units. Each curve represents one assessment unit and is 

based on the input data in table 11. Black diamonds show the mean value for each curve. [EUR, estimated ultimate recovery; BCFG, 

billions of cubic feet of gas]
Figures 13

1

0.1

100

10

Estimated ultimate recovery (BCFG)

EUR—Tight Gas

Fractile, in percent

100 90 80 70 60 50 40 30 20 10 0

0.01

Figure 11. Cloud plot for EURs in United States tight-gas assessment units. Each curve represents one assessment unit and is based 

on the input data in table 12. Black diamonds show the mean value for each curve. [EUR, estimated ultimate recovery; BCFG, billions of 

cubic feet of gas] 
14 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

0.1

0.01

10

1

Estimated ultimate recovery (BCFG)

EUR—Continuous Oil

Fractile, in percent

100 90 80 70 60 50 40 30 20 10 0

0.001

Figure 12. Cloud plot for EURs in United States continuous-oil assessment units. Each curve represents one assessment unit and is 

based on the input data in table 13. Black diamonds show the mean value for each curve. [EUR, estimated ultimate recovery; MMBO, 

millions of barrels of oil]
Tables 15

Table 2. Input data for estimated area of cells (drainage areas) for United States shale-gas assessment units, values in acres.

[AU, assessment unit]

AU 

number AU name Province Yearassessed

Minimum

cell

area

Mode 

of cell

area

Maximum

cell

area

Mean

cell

area

50580161 Woodford Shale Gas Anadarko Basin 2010 60 120 320 166.67

50580261 Thirteen Finger Limestone-Atoka Shale Gas Anadarko Basin 2010 60 120 320 166.67

50620261 Woodford Shale Gas Arkoma Basin 2010 60 120 320 166.67

50620262 Chattanooga Shale Gas Arkoma Basin 2010 60 120 320 166.67

50620364 Caney Shale Gas Arkoma Basin 2010 40 120 320 160.00

50640361 Devonian to Mississippian New Albany Continuous Gas Illinois Basin 2007 80 160 240 160.00

50390761 Niobrara Chalk Denver Basin 2001 35 43.70 400 159.57

50490161 Haynesville Sabine Platform Shale Gas Gulf Coast Mesozoic 2010 80 128 240 149.33

50490163 Mid-Bossier Sabine Platform Shale Gas Gulf Coast Mesozoic 2010 80 128 240 149.33

50490165 Maverick Basin Pearsall Shale Gas Gulf Coast Mesozoic 2010 80 128 240 149.33

50490167 Eagle Ford Shale Gas Gulf Coast Mesozoic 2010 80 128 240 149.33

50670467 Foldbelt Marcellus Appalachian Basin 2011 80 128 240 149.33

50670468 Interior Marcellus Appalachian Basin 2011 80 128 240 149.33

50620362 Fayetteville Shale Gas-High Gamma-Ray Depocenter Arkoma Basin 2010 40 80 320 146.67

50620363 Fayetteville Shale Gas-Western Arkansas Basin Margin Arkoma Basin 2010 40 80 320 146.67

50210362 Cane Creek Shale Gas Paradox Basin 2011 70 120 240 143.33

50210364 Gothic, Chimney Rock, Hovenweep Shale Gas Paradox Basin 2011 70 120 240 143.33

50670469 Western Margin Marcellus Appalachian Basin 2011 20 90 240 116.67

50670463 Devonian Siltstone and Shale Appalachian Basin 2002 20 86.36 240 115.45

50670464 Marcellus Shale Appalachian Basin 2002 20 88.89 200 102.96

50440161 Delaware/Pecos Basins Woodford Continuous Shale Gas Permian Basin 2007 40 80 160 93.33

50440162 Delaware/Pecos Basins Barnett Continuous Shale Gas Permian Basin 2007 40 80 160 93.33

50440163 Midland Basin Woodford/Barnett Continuous Gas Permian Basin 2007 40 80 160 93.33

50630561 Devonian Antrim Continuous Gas Michigan Basin 2004 20 80 160 86.67

50670462 Northwestern Ohio Shale Appalachian Basin 2002 10 74.67 160 81.56

50450161 Greater Newark East Frac-Barrier Continuous Barnett 

Shale Gas

Bend ArchFort Worth Basin2003 10 40 110 53.33

50450162 Extended Continuous Barnett Shale Gas Bend ArchFort Worth Basin2003 10 40 110 53.33
16 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

Table 3. Input data for estimated area of cells (drainage areas) for United States coalbed-gas assessment units, values in acres.

[AU, assessment unit]

AU

number AU name Province Yearassessed

Minimum

cell

area

Mode

of cell

area

Maximum

cell

area

Mean

cell

area

50220181 Fruitland Fairway Coalbed Gas San Juan Basin 2002 20 149.33 320 163.11

50620481 Arkoma Coalbed Gas Arkoma Basin 2010 40 160 280 160.00

50640481 Desmoinesian-Virgilian Coalbed Gas Illinois Basin 2007 60 160 260 160.00

50350281 Mesaverde Coalbed Gas Wind River Basin 2005 40 120 280 146.67

50350282 Meeteetse Coalbed Gas Wind River Basin 2005 40 120 280 146.67

50410181 Raton Coalbed Gas Raton BasinSierra Grande Uplift2004 80 120 240 146.67

50410182 Vermejo Coalbed Gas Raton BasinSierra Grande Uplift2004 80 120 240 146.67

50010181 Nanushuk Formation Coalbed Gas Northern Alaska 2006 40 100 280 140.00

50210581 Kaiparowits Plateau Paradox Basin 2011 40 67 280 129.00

50200181 Northern Coal Fairway/Drunkards Wash Uinta-Piceance 2000 40 66.67 280 128.89

50200281 Uinta Basin Blackhawk Coalbed Gas Uinta-Piceance 2000 40 66.67 280 128.89

50200282 Mesaverde Group Coalbed Gas Uinta-Piceance 2000 40 66.67 280 128.89

50220381 Menefee Coalbed Gas San Juan Basin 2002 40 66.67 280 128.89

50370581 Mesaverde Coalbed Gas Southwestern Wyoming 2002 40 66.67 280 128.89

50370681 Mesaverde Coalbed Gas Southwestern Wyoming 2002 40 66.67 280 128.89

50340281 Mesaverde-Meeteetse Formation Coalbed Gas Big Horn Basin 2008 40 100 240 126.67

50200183 Southern Coal Fairway Uinta-Piceance 2000 40 57.96 250 115.99

50010182 Prince Creek–Tuluvak Formations Coalbed Gas Northern Alaska 2006 40 100 200 113.33

50010183 Sagavanirktok Formation Coalbed Gas Northern Alaska 2006 40 100 200 113.33

50340282 Fort Union Formation Coalbed Gas Big Horn Basin 2008 40 100 200 113.33

50200182 Central Coal Fairway/Buzzards Bench Uinta-Piceance 2000 40 41.39 250 110.46

50200185 Southern Coal Outcrop Uinta-Piceance 2001 40 41.39 250 110.46

50360281 Frontier-Adaville-Evanston Coalbed Gas Wyoming Thrust Belt 2003 40 40 250 110.00

50220182 Basin Fruitland Coalbed Gas San Juan Basin 2002 20 61.82 240 107.27

50311081 Fort Union Coalbed Gas Williston Basin 2008 40 100 180 106.67

50040381 Eocene Coalbed Gas Western OregonWashington2009 40 80 180 100.00

50030281 Cook Inlet Coalbed Gas Southern Alaska 2011 40 80 140 86.67

50350283 Fort Union Coalbed Gas Wind River Basin 2005 40 80 140 86.67

50330181 Wasatch Formation Powder River Basin 2000 40 68 140 82.67

50330182 Upper Fort Union Formation Powder River Basin 2000 40 68 140 82.67

50330183 Lower Fort Union-Lance Formations Powder River Basin 2000 40 68 140 82.67

50370682 Fort Union Coalbed Gas Southwestern Wyoming 2002 40 68 140 82.67

50370881 Lance Coalbed Gas Southwestern Wyoming 2002 40 68 140 82.67

50370882 Fort Union Coalbed Gas Southwestern Wyoming 2002 40 68 140 82.67

50370981 Wasatch-Green River Coalbed Gas Southwestern Wyoming 2002 40 68 140 82.67

50650281 Warrior Basin Warrior Basin 2002 30 40 120 63.33

50670581 Pocahontas Basin Appalachian Basin 2002 40 46.67 100 62.22

50470381 Wilcox Coalbed Gas Gulf Coast Cenozoic 2007 10 40 120 56.67

50670582 Eastern Dunkard Basin Appalachian Basin 2002 30 36.67 90 52.22

50470281 Cretaceous Olmos Coalbed Gas Gulf Coast Cenozoic 2007 10 40 80 43.33

53000281 Rio Escondido Basin Olmos Coalbed Gas Burgos Basin 2007 10 40 80 43.33
Tables 17

Table 4. Input data for estimated area of cells (drainage areas) for United States tight-gas assessment units, values in acres. 

[AU, assessment unit]

AU

number AU name Province Yearassessed

Minimum

cell

area

Mode

of cell

area

Maximum

cell

area

Mean

cell

area

50340263 Cody Sandstone Continuous Gas Big Horn Basin 2008 40 160 640 280.00

50350262 Cody Sandstones Continuous Gas Wind River Basin 2005 40 160 640 280.00

50280162 Eagle Sandstone and Claggett Shale East North-Central Montana 2000 80 158.99 320 186.33

50280163 Eagle Sandstone and Claggett Shale West North-Central Montana 2000 80 158.99 320 186.33

50280165 Greenhorn-Lower Belle Fourche North-Central Montana 2000 80 158.99 320 186.33

50280166 Greenhorn-Upper Belle Fourche North-Central Montana 2000 80 158.99 320 186.33

50030161 Tuxedni-Naknek Continuous Gas Southern Alaska 2011 80 140 320 180.00

50370561 Almond Continuous Gas Southwestern Wyoming 2002 40 40.58 449 176.53

50200161 Deep (6,000 feet plus) Coal and Sandstone Gas Uinta-Piceance 2000 60 123.08 320 167.69

50330461 Shallow Continuous Biogenic Gas Powder River Basin 2002 40 137.14 320 165.71

50280161 Judith River Formation North-Central Montana 2000 40 160 280 160.00

50350261 Frontier-Muddy Continuous Gas Wind River Basin 2005 40 120 300 153.33

50620161 Arkoma-Ouachita Foredeep Continuous Arkoma Basin 2010 40 100 320 153.33

50220361 Mesaverde Central-Basin Continuous Gas San Juan Basin 2002 40 88.57 320 149.52

50280164 Niobrara-Carlile North-Central Montana 2000 40 88.57 320 149.52

50220363 Dakota-Greenhorn Continuous Gas San Juan Basin 2002 40 43.59 360 147.86

50200363 Uinta-Piceance Transitional and Migrated Gas Uinta-Piceance 2000 30 124.76 240 131.59

50370261 Mowry Continuous Gas Southwestern Wyoming 2002 40 50.77 300 130.26

50340261 Muddy-Frontier Sandstone and Mowry 

Fractured Shale Continuous Gas

Big Horn Basin 2008 40 50 300 130.00

50050161 Columbia Basin Continuous Gas Eastern Oregon-Washington 2006 40 120 200 120.00

50700161 Taylorsville Basin Continuous Gas Atlantic Coastal Plain 2011 40 80 240 120.00

50700261 Richmond Basin Continuous Gas Atlantic Coastal Plain 2011 40 80 240 120.00

50700361 South Newark Basin Continuous Gas Atlantic Coastal Plain 2011 40 80 240 120.00

50700461 Deep River Basin Continuous Gas Atlantic Coastal Plain 2011 40 80 240 120.00

50701061 Dan River-Danville Basin Continuous Gas Atlantic Coastal Plain 2011 40 80 240 120.00

50200361 Piceance Basin Continuous Gas Uinta-Piceance 2000 30 79.05 240 116.35

50200362 Uinta Basin Continuous Gas Uinta-Piceance 2000 30 79.05 240 116.35

50280167 Bowdoin Dome North-Central Montana 2000 40 121.67 160 107.22

50220261 Lewis Continuous Gas San Juan Basin 2002 40 75 200 105.00

50220362 Mancos Sandstones Continuous Gas San Juan Basin 2002 40 75 200 105.00

50370661 Mesaverde-Lance-Fort Union Continuous Gas Southwestern Wyoming 2002 40 75 200 105.00

50370761 Lewis Continuous Gas Southwestern Wyoming 2002 20 88.89 200 102.96

50670461 Greater Big Sandy Appalachian Basin 2002 20 88.89 200 102.96

50200261 Uinta Basin Continuous Gas Uinta-Piceance 2000 20 40.87 240 100.29

50200262 Uinta Basin Transitional Gas Uinta-Piceance 2000 20 40.87 240 100.29

50220161 Pictured Cliffs Continuous Gas San Juan Basin 2002 40 48.75 200 96.25

50390662 Dakota Group Basin-Center Gas Denver Basin 2001 10 17.39 240 89.13

50370861 Lance-Fort Union Continuous Gas Southwestern Wyoming 2002 20 40 200 86.67

50200264 Piceance Basin Transitional Gas Uinta-Piceance 2000 20 55 180 85.00

50370461 Hilliard-Baxter-Mancos Continuous Gas Southwestern Wyoming 2002 20 55 180 85.00

50370562 Rock Springs-Ericson Continuous Gas Southwestern Wyoming 2002 20 55 180 85.00

50670364 Tuscarora Basin Center Appalachian Basin 2002 40 53.33 160 84.44

50340264 Mesaverde Sandstone Continuous Gas Big Horn Basin 2008 20 50 180 83.33

50350264 Mesaverde-Meeteetse Sandstone Gas Wind River Basin 2005 20 50 180 83.33

50350265 Lance-Fort Union Sandstone Gas Wind River Basin 2005 20 60 160 80.00

50200263 Piceance Basin Continuous Gas Uinta-Piceance 2000 20 20.39 180 73.46

50670465 Catskill Sandstones and Siltstones Appalachian Basin 2002 10 41.54 140 63.85

50670361 Clinton-Medina Basin Center Appalachian Basin 2002 10 12 110 44.00

50670362 Clinton-Medina Transitional Northeast Appalachian Basin 2002 10 12 110 44.00

50670363 Clinton-Medina Transitional Appalachian Basin 2002 10 12 110 44.00

50670466 Berea Sandstone Appalachian Basin 2002 10 34.29 80 41.43
18 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

Table 5. Input data for estimated area of cells (drainage areas) for United States continuous-oil assessment units, values in acres.

[AU, assessment unit]

AU

number AU name Province Yearassessed

Minimum

cell

area

Mode 

of cell

area

Maximum

cell

area

Mean

cell

area

50210361 Cane Creek Shale Oil Paradox Basin 2011 80 320 800 400.00

50210363 Gothic, Chimney Rock, Hovenweep Shale Oil Paradox Basin 2011 80 320 800 400.00

50310161 Elm Coulee-Billings Nose Williston Basin 2008 80 320 800 400.00

50310163 Nesson-Little Knife Structural Williston Basin 2008 80 320 800 400.00

50310164 Eastern Expulsion Threshold Williston Basin 2008 80 320 800 400.00

50310165 Northwest Expulsion Threshold Williston Basin 2008 80 320 800 400.00

50200561 Deep Uinta Overpressured Continuous Oil Uinta-Piceance 2000 80 239.20 640 319.73

50310162 Central Basin-Poplar Dome Williston Basin 2008 80 200 640 306.67

50340262 Mowry Fractured Shale Continuous Oil Big Horn Basin 2008 40 185 640 288.33

50330261 Mowry Continuous Oil Powder River Basin 2002 40 183.67 640 287.89

50490170 Eagle Ford Shale Oil Gulf Coast Mesozoic 2010 80 128 320 176.00

50270561 Marias River Shale Continuous Oil Montana Thrust Belt 2002 40 80 400 173.33

50300361 Niobrara Continuous Oil Hanna, Laramie, 

Shirley Basins

2005 40 160 320 173.33

50370361 Niobrara Continuous Oil Southwestern Wyoming 2002 40 80 400 173.33

50490168 Austin Pearsall-Giddings Area Oil Gulf Coast Mesozoic 2010 100 140 240 160.00

50330361 Niobrara Continuous Oil Powder River Basin 2002 10 87.10 320 139.03

50580162 Woodford Shale Oil Anadarko Basin 2010 10 85 320 138.33

50390261 Fractured Niobrara Limestone (Silo Field Area) Denver Basin 2001 10 10.57 320 113.52

50440165 Spraberry Continuous Oil Permian Basin 2007 40 80 120 80.00

50390661 Niobrara-Codell (Wattenberg Area) Denver Basin 2001 10 18.33 85 37.78
Tables 19

Table 6. Input data for estimated percent of untested area in sweet spots for United States shale-gas assessment units.

[AU, assessment unit; %, percent]

AU

number AU name Province Yearassessed

Minimum

sweet

spot %

Mode

of sweet

spot %

Maximum

sweet

spot %

Mean

sweet

spot %

50450161 Greater Newark East Frac-Barrier Continuous Barnett 

Shale Gas

Bend ArchFort Worth Basin2003 75 88 95 86.00

50490161 Haynesville Sabine Platform Shale Gas Gulf Coast Mesozoic 2010 35 60 90 61.67

50450162 Extended Continuous Barnett Shale Gas Bend ArchFort Worth Basin2003 35 55 90 60.00

50210362 Cane Creek Shale Gas Paradox Basin 2011 5 60 90 51.67

50620362 Fayetteville Shale Gas-High Gamma-Ray Depocenter Arkoma Basin 2010 25 50 80 51.67

50490163 Mid-Bossier Sabine Platform Shale Gas Gulf Coast Mesozoic 2010 15 35 85 45.00

50620261 Woodford Shale Gas Arkoma Basin 2010 10 35 70 38.33

50620363 Fayetteville Shale Gas-Western Arkansas Basin Margin Arkoma Basin 2010 5 40 70 38.33

50670468 Interior Marcellus Appalachian Basin 2011 10 25 75 36.67

50580161 Woodford Shale Gas Anadarko Basin 2010 5 35 60 33.33

50490165 Maverick Basin Pearsall Shale Gas Gulf Coast Mesozoic 2010 1 15 80 32.00

50440163 Midland Basin Woodford/Barnett Continuous Gas Permian Basin 2007 9 25 60 31.33

50440161 Delaware/Pecos Basins Woodford Continuous Shale Gas Permian Basin 2007 12 32 43 29.00

50580261 Thirteen Finger Limestone-Atoka Shale Gas Anadarko Basin 2010 1 20 60 27.00

50670463 Devonian Siltstone and Shale Appalachian Basin 2002 14 19.93 44 25.98

50440162 Delaware/Pecos Basins Barnett Continuous Shale Gas Permian Basin 2007 8 20 43 23.67

50620262 Chattanooga Shale Gas Arkoma Basin 2010 3 18 45 22.00

50210364 Gothic, Chimney Rock, Hovenweep Shale Gas Paradox Basin 2011 0.5 25 40 21.83

50620364 Caney Shale Gas Arkoma Basin 2010 1 20 40 20.33

50490167 Eagle Ford Shale Gas Gulf Coast Mesozoic 2010 0.5 12 30 14.17

50670462 Northwestern Ohio Shale Appalachian Basin 2002 6 8.33 27 13.78

50640361 Devonian to Mississippian New Albany Continuous Gas Illinois Basin 2007 0.4 3 30 11.13

50670464 Marcellus Shale Appalachian Basin 2002 0.1 5.17 17 7.42

50670469 Western Margin Marcellus Appalachian Basin 2011 0.5 6.5 15 7.33

50670467 Foldbelt Marcellus Appalachian Basin 2011 0.5 3 10 4.50

50630561 Devonian Antrim Continuous Gas Michigan Basin 2004 2 3.5 5 3.50

50390761 Niobrara Chalk Denver Basin 2001 0.2 0.25 3.9 1.45
20 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

Table 7. Input data for estimated percent of untested area in sweet spots for United States coalbed-gas assessment units.

[AU, assessment unit; %, percent]

AU

number AU name Province Yearassessed

Minimum

sweet

spot %

Mode

of sweet

spot %

Maximum

sweet

spot %

Mean

sweet

spot %

50220181 Fruitland Fairway Coalbed Gas San Juan Basin 2002 93 95 97 95.00

50220182 Basin Fruitland Coalbed Gas San Juan Basin 2002 45 58.33 60 54.44

50200181 Northern Coal Fairway/Drunkards Wash Uinta-Piceance 2000 10 68.70 79 52.57

50670581 Pocahontas Basin Appalachian Basin 2002 35 42 60 45.67

50200182 Central Coal Fairway/Buzzards Bench Uinta-Piceance 2000 5 48.56 55 36.19

50620481 Arkoma Coalbed Gas Arkoma Basin 2010 15 30 60 35.00

50200185 Southern Coal Outcrop Uinta-Piceance 2001 8 16 80 34.67

50330182 Upper Fort Union Formation Powder River Basin 2000 10 31.96 58 33.32

50200183 Southern Coal Fairway Uinta-Piceance 2000 1 48.18 50 33.06

50410182 Vermejo Coalbed Gas Raton BasinSierra Grande Uplift2004 10 25 50 28.33

50650281 Warrior Basin Warrior Basin 2002 9.2 30.66 39.4 26.42

50030281 Cook Inlet Coalbed Gas Southern Alaska 2011 0.5 6 63 23.17

50670582 Eastern Dunkard Basin Appalachian Basin 2002 4 20.52 35 19.84

50210581 Kaiparowits Plateau Paradox Basin 2011 0.5 15 40 18.50

50360281 Frontier-Adaville-Evanston Coalbed Gas Wyoming Thrust Belt 2003 1 10 41 17.33

50410181 Raton Coalbed Gas Raton BasinSierra Grande Uplift2004 4 13 34 17.00

50010181 Nanushuk Formation Coalbed Gas Northern Alaska 2006 0.5 7.5 38 15.33

50010183 Sagavanirktok Formation Coalbed Gas Northern Alaska 2006 0.3 8 35 14.43

50330181 Wasatch Formation Powder River Basin 2000 1 13.52 24 12.84

53000281 Rio Escondido Basin Olmos Coalbed Gas Burgos Basin 2007 1 11 25 12.33

50350281 Mesaverde Coalbed Gas Wind River Basin 2005 1 7 27 11.67

50370882 Fort Union Coalbed Gas Southwestern Wyoming 2002 3 8.24 20 10.41

50370581 Mesaverde Coalbed Gas Southwestern Wyoming 2002 1 9.47 20 10.16

50370681 Mesaverde Coalbed Gas Southwestern Wyoming 2002 1 9.47 20 10.16

50220381 Menefee Coalbed Gas San Juan Basin 2002 1 2.08 27 10.03

50470281 Cretaceous Olmos Coalbed Gas Gulf Coast Cenozoic 2007 1 8 20 9.67

50040381 Eocene Coalbed Gas Western OregonWashington2009 1 3.10 22 8.70

50470381 Wilcox Coalbed Gas Gulf Coast Cenozoic 2007 0.1 5 20 8.37

50200281 Uinta Basin Blackhawk Coalbed Gas Uinta-Piceance 2000 0.5 2.67 20 7.72

50640481 Desmoinesian-Virgilian Coalbed Gas Illinois Basin 2007 0.25 4 16 6.75

50370981 Wasatch-Green River Coalbed Gas Southwestern Wyoming 2002 1 3.43 15 6.48

50010182 Prince Creek–Tuluvak Formations Coalbed Gas Northern Alaska 2006 0.2 5 14 6.40

50350282 Meeteetse Coalbed Gas Wind River Basin 2005 1 3 15 6.33

50340281 Mesaverde-Meeteetse Formation Coalbed Gas Big Horn Basin 2008 0.5 2.50 14 5.67

50200282 Mesaverde Group Coalbed Gas Uinta-Piceance 2000 1 1.54 14 5.51

50350283 Fort Union Coalbed Gas Wind River Basin 2005 0.5 3 13 5.50

50370682 Fort Union Coalbed Gas Southwestern Wyoming 2002 1 2 10 4.33

50330183 Lower Fort Union-Lance Formations Powder River Basin 2000 0.002 1.00 9 3.33

50370881 Lance Coalbed Gas Southwestern Wyoming 2002 1 1.67 7 3.22

50311081 Fort Union Coalbed Gas Williston Basin 2008 0.01 2 7 3.00

50340282 Fort Union Formation Coalbed Gas Big Horn Basin 2008 0.1 1 3 1.37
Tables 21

Table 8. Input data for estimated percent of untested area in sweet spots for United States tight-gas assessment units.

[AU, assessment unit; %, percent]

AU

number AU name Province Yearassessed

Minimum

sweet

spot %

Mode

of sweet

spot %

Maximum

sweet

spot %

Mean

sweet

spot %

50220362 Mancos Sandstones Continuous Gas San Juan Basin 2002 35 66.25 75 58.75

50220363 Dakota-Greenhorn Continuous Gas San Juan Basin 2002 46 46.6 76 56.20

50670363 Clinton-Medina Transitional Appalachian Basin 2002 40 50.84 77 55.95

50670461 Greater Big Sandy Appalachian Basin 2002 14 61.35 85 53.45

50370561 Almond Continuous Gas Southwestern Wyoming 2002 35 47.90 76 52.97

50670361 Clinton-Medina Basin Center Appalachian Basin 2002 10 51.03 88 49.68

50370562 Rock Springs-Ericson Continuous Gas Southwestern Wyoming 2002 28 45.82 72 48.61

50370761 Lewis Continuous Gas Southwestern Wyoming 2002 18 40.41 69 42.47

50030161 Tuxedni-Naknek Continuous Gas Southern Alaska 2011 0.5 24 95 39.83

50220161 Pictured Cliffs Continuous Gas San Juan Basin 2002 14 46.06 47 35.69

50700261 Richmond Basin Continuous Gas Atlantic Coastal Plain 2011 7.5 21 76 34.83

50700361 South Newark Basin Continuous Gas Atlantic Coastal Plain 2011 1 21 81 34.33

50220261 Lewis Continuous Gas San Juan Basin 2002 23 37.24 40 33.41

50700461 Deep River Basin Continuous Gas Atlantic Coastal Plain 2011 6 21 71 32.67

50390662 Dakota Group Basin-Center Gas Denver Basin 2001 20 27 45 30.67

50200261 Uinta Basin Continuous Gas Uinta-Piceance 2000 4 33.39 50 29.13

50670465 Catskill Sandstones and Siltstones Appalachian Basin 2002 15 17.42 53 28.47

50700161 Taylorsville Basin Continuous Gas Atlantic Coastal Plain 2011 6 19 60 28.33

50200363 Uinta-Piceance Transitional and Migrated Gas Uinta-Piceance 2000 20 29.14 34 27.71

50370661 Mesaverde-Lance-Fort Union Continuous Gas Southwestern Wyoming 2002 14 16.55 45 25.18

50370861 Lance-Fort Union Continuous Gas Southwestern Wyoming 2002 5 27.86 40 24.29

50620161 Arkoma-Ouachita Foredeep Continuous Arkoma Basin 2010 2 20 50 24.00

50050161 Columbia Basin Continuous Gas Eastern Oregon-Washington 2006 5 20 40 21.67

50220361 Mesaverde Central-Basin Continuous Gas San Juan Basin 2002 15 23.91 26 21.64

50670466 Berea Sandstone Appalachian Basin 2002 3 5.15 55 21.05

50200262 Uinta Basin Transitional Gas Uinta-Piceance 2000 12 13.08 38 21.03

50200263 Piceance Basin Continuous Gas Uinta-Piceance 2000 8 18.33 35 20.44

50280167 Bowdoin Dome North-Central Montana 2000 8 20 32 20.00

50200361 Piceance Basin Continuous Gas Uinta-Piceance 2000 4 6.29 49 19.76

50670362 Clinton-Medina Transitional Northeast Appalachian Basin 2002 2 4.63 50 18.88

50701061 Dan River-Danville Basin Continuous Gas Atlantic Coastal Plain 2011 0.2 5 45 16.73

50370461 Hilliard-Baxter-Mancos Continuous Gas Southwestern Wyoming 2002 2 7.53 36 15.18

50200264 Piceance Basin Transitional Gas Uinta-Piceance 2000 1 13.74 20 11.58

50200161 Deep (6,000 feet plus) Coal and Sandstone Gas Uinta-Piceance 2000 1 2.41 30 11.14

50200362 Uinta Basin Continuous Gas Uinta-Piceance 2000 5 5.54 18 9.51

50370261 Mowry Continuous Gas Southwestern Wyoming 2002 6 9 12 9.00

50340261 Muddy-Frontier Sandstone and 

Mowry Fractured Shale Continuous Gas

Big Horn Basin 2008 0.6 2 22.5 8.37

50340263 Cody Sandstone Continuous Gas Big Horn Basin 2008 0.3 3 19.6 7.63

50280161 Judith River Formation North-Central Montana 2000 0.1 0.30 20 6.80

50350265 Lance-Fort Union Sandstone Gas Wind River Basin 2005 2 4 12 6.00

50280163 Eagle Sandstone and Claggett Shale West North-Central Montana 2000 0.8 2.51 13 5.44

50330461 Shallow Continuous Biogenic Gas Powder River Basin 2002 1 2.72 12.5 5.41

50350261 Frontier-Muddy Continuous Gas Wind River Basin 2005 0.7 1.6 9 3.77

50340264 Mesaverde Sandstone Continuous Gas Big Horn Basin 2008 0.2 2.1 8.5 3.60

50350262 Cody Sandstones Continuous Gas Wind River Basin 2005 0.8 1.4 8 3.40

50350264 Mesaverde-Meeteetse Sandstone Gas Wind River Basin 2005 0.5 1.5 7 3.00

50280162 Eagle Sandstone and Claggett Shale East North-Central Montana 2000 0.1 1.33 5 2.14

50280166 Greenhorn-Upper Belle Fourche North-Central Montana 2000 0.1 0.16 3.1 1.12

50670364 Tuscarora Basin Center Appalachian Basin 2002 0.1 0.29 2.6 1.00

50280165 Greenhorn-Lower Belle Fourche North-Central Montana 2000 0.1 0.14 2.1 0.78

50280164 Niobrara-Carlile North-Central Montana 2000 0.01 0.04 1 0.35
22 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

Table 9. Input data for estimated percent of untested area in sweet spots for United States continuous-oil assessment units.

[AU, assessment unit; %, percent]

AU

number AU name Province Yearassessed

Minimum

sweet

spot %

Mode

of sweet

spot %

Maximum

sweet

spot %

Mean

sweet

spot %

50310161 Elm Coulee-Billings Nose Williston Basin 2008 80 92 95 89.00

50310163 Nesson-Little Knife Structural Williston Basin 2008 75 92 98 88.33

50310164 Eastern Expulsion Threshold Williston Basin 2008 70 85 96 83.67

50310162 Central Basin-Poplar Dome Williston Basin 2008 50 80 92 74.00

50310165 Northwest Expulsion Threshold Williston Basin 2008 30 75 92 65.67

50200561 Deep Uinta Overpressured Continuous Oil Uinta-Piceance 2000 35 40 80 51.67

50440165 Spraberry Continuous Oil Permian Basin 2007 22 58 66 48.67

50210361 Cane Creek Shale Oil Paradox Basin 2011 5 35 92 44.00

50490168 Austin Pearsall-Giddings Area Oil Gulf Coast Mesozoic 2010 16 30 75 40.33

50330261 Mowry Continuous Oil Powder River Basin 2002 8 23.38 45 25.46

50490170 Eagle Ford Shale Oil Gulf Coast Mesozoic 2010 0.5 9 40 16.50

50330361 Niobrara Continuous Oil Powder River Basin 2002 4.1 17.20 27.2 16.17

50210363 Gothic, Chimney Rock, Hovenweep Shale Oil Paradox Basin 2011 0.5 15 30 15.17

50300361 Niobrara Continuous Oil Hanna, Laramie,

Shirley Basins

2005 1 4 25 10.00

50390661 Niobrara-Codell (Wattenberg Area) Denver Basin 2001 2 5.15 15 7.38

50580162 Woodford Shale Oil Anadarko Basin 2010 0.25 5 15 6.75

50340262 Mowry Fractured Shale Continuous Oil Big Horn Basin 2008 0.1 1.25 17 6.12

50370361 Niobrara Continuous Oil Southwestern Wyoming 2002 2 5 8 5.00

50390261 Fractured Niobrara Limestone (Silo Field Area) Denver Basin 2001 2 2.67 8 4.22

50270561 Marias River Shale Continuous Oil Montana Thrust Belt 2002 0.5 2.6 8 3.70

Table 10. Input data for estimated ultimate recovery distributions for United States shale-gas assessment units, values in billions 

of cubic feet of natural gas.

[AU, assessment unit; EUR, estimated ultimate recovery]

AU

number AU name Province Yearassessed

Minimum

EUR

Median

EUR

Maximum

EUR

Mean

EUR

50490161 Haynesville Sabine Platform Shale Gas Gulf Coast Mesozoic 2010 0.02 2 20 2.617

50490163 Mid-Bossier Sabine Platform Shale Gas Gulf Coast Mesozoic 2010 0.02 1 10 1.308

50580161 Woodford Shale Gas Anadarko Basin 2010 0.02 0.8 15 1.233

50670468 Interior Marcellus Appalachian Basin 2011 0.02 0.8 12 1.158

50490167 Eagle Ford Shale Gas Gulf Coast Mesozoic 2010 0.02 0.8 10 1.104

50620362 Fayetteville Shale Gas-High GammaRay DepocenterArkoma Basin 2010 0.02 0.8 10 1.104

50450161 Greater Newark East Frac-Barrier Continuous Barnett 

Shale Gas

Bend ArchFort Worth Basin2003 0.02 0.7 10 1.000

50440161 Delaware/Pecos Basins Woodford Continuous Shale Gas Permian Basin 2007 0.02 0.6 8 0.842

50440162 Delaware/Pecos Basins Barnett Continuous Shale Gas Permian Basin 2007 0.02 0.6 8 0.842

50580261 Thirteen Finger Limestone-Atoka Shale Gas Anadarko Basin 2010 0.02 0.5 10 0.785

50620261 Woodford Shale Gas Arkoma Basin 2010 0.02 0.5 10 0.785

50210364 Gothic, Chimney Rock, Hovenweep Shale Gas Paradox Basin 2011 0.02 0.4 10 0.672

50630561 Devonian Antrim Continuous Gas Michigan Basin 2004 0.02 0.4 4 0.523

50620363 Fayetteville Shale Gas - Western Arkansas Basin Margin Arkoma Basin 2010 0.02 0.3 6 0.470

50210362 Cane Creek Shale Gas Paradox Basin 2011 0.02 0.3 5 0.446

50440163 Midland Basin Woodford/Barnett Continuous Gas Permian Basin 2007 0.02 0.3 5 0.446

50490165 Maverick Basin Pearsall Shale Gas Gulf Coast Mesozoic 2010 0.02 0.25 5 0.391

50450162 Extended Continuous Barnett Shale Gas Bend ArchFort Worth Basin2003 0.02 0.2 5 0.334

50390761 Niobrara Chalk Denver Basin 2001 0.025 0.2 2 0.261

50620262 Chattanooga Shale Gas Arkoma Basin 2010 0.02 0.1 6 0.223

50670467 Foldbelt Marcellus Appalachian Basin 2011 0.02 0.1 5 0.208

50620364 Caney Shale Gas Arkoma Basin 2010 0.02 0.08 5 0.179

50670469 Western Margin Marcellus Appalachian Basin 2011 0.02 0.05 5 0.129

50640361 Devonian to Mississippian New Albany Continuous Gas Illinois Basin 2007 0.01 0.08 1 0.110

50670462 Northwestern Ohio Shale Appalachian Basin 2002 0.01 0.04 0.5 0.055

50670463 Devonian Siltstone and Shale Appalachian Basin 2002 0.01 0.03 0.5 0.044

50670464 Marcellus Shale Appalachian Basin 2002 0.01 0.03 0.5 0.044
Tables 23

Table 11. Input data for estimated ultimate recovery distributions for United States coalbed-gas assessment units, values in billions of 

cubic feet of natural gas.

[AU, assessment unit; EUR, estimated ultimate recovery]

AU

number AU name Province Yearassessed

Minimum

EUR

Median

EUR

Maximum

EUR

Mean

EUR

50220181 Fruitland Fairway Coalbed Gas San Juan Basin 2002 0.02 8 40 9.125

50200181 Northern Coal Fairway/Drunkards Wash Uinta-Piceance 2000 0.05 0.8 12 1.156

50220182 Basin Fruitland Coalbed Gas San Juan Basin 2002 0.02 0.6 20 1.110

50200182 Central Coal Fairway/Buzzards Bench Uinta-Piceance 2000 0.05 0.4 10 0.666

50010181 Nanushuk Formation Coalbed Gas Northern Alaska 2006 0.02 0.25 12 0.524

50410182 Vermejo Coalbed Gas Raton BasinSierra Grande Uplift2004 0.02 0.25 9.5 0.481

50200281 Uinta Basin Blackhawk Coalbed Gas Uinta-Piceance 2000 0.05 0.25 10 0.480

50360281 Frontier-Adaville-Evanston Coalbed Gas Wyoming Thrust Belt 2003 0.02 0.4 2 0.456

50410181 Raton Coalbed Gas Raton BasinSierra Grande Uplift2004 0.02 0.25 8 0.453

50650281 Warrior Basin Warrior Basin 2002 0.01 0.25 5 0.392

50620481 Arkoma Coalbed Gas Arkoma Basin 2010 0.02 0.3 3 0.392

50330182 Upper Fort Union Formation Powder River Basin 2000 0.02 0.23 4 0.345

50200183 Southern Coal Fairway Uinta-Piceance 2000 0.05 0.2 5 0.328

50210581 Kaiparowits Plateau Paradox Basin 2011 0.02 0.2 4 0.312

50010183 Sagavanirktok Formation Coalbed Gas Northern Alaska 2006 0.02 0.18 5 0.310

50330181 Wasatch Formation Powder River Basin 2000 0.02 0.18 3 0.267

50370882 Fort Union Coalbed Gas Southwestern Wyoming 2002 0.02 0.2 1.5 0.246

50670581 Pocahontas Basin Appalachian Basin 2002 0.01 0.15 2 0.210

50350281 Mesaverde Coalbed Gas Wind River Basin 2005 0.02 0.1 5 0.208

50030281 Cook Inlet Coalbed Gas Southern Alaska 2011 0.02 0.16 1.5 0.206

50370881 Lance Coalbed Gas Southwestern Wyoming 2002 0.02 0.15 1 0.180

50200282 Mesaverde Group Coalbed Gas Uinta-Piceance 2000 0.02 0.08 5 0.179

50220381 Menefee Coalbed Gas San Juan Basin 2002 0.02 0.08 5 0.179

50200185 Southern Coal Outcrop Uinta-Piceance 2001 0.05 0.1 3 0.165

50670582 Eastern Dunkard Basin Appalachian Basin 2002 0.01 0.1 2 0.156

50040381 Eocene Coalbed Gas Western OregonWashington2009 0.02 0.1 2 0.155

50010182 Prince Creek–Tuluvak Formations Coalbed Gas Northern Alaska 2006 0.02 0.1 1.5 0.143

50340281 Mesaverde-Meeteetse Formation Coalbed Gas Big Horn Basin 2008 0.02 0.1 1.2 0.136

50350282 Meeteetse Coalbed Gas Wind River Basin 2005 0.02 0.08 2 0.131

50350283 Fort Union Coalbed Gas Wind River Basin 2005 0.02 0.08 2 0.131

50370682 Fort Union Coalbed Gas Southwestern Wyoming 2002 0.02 0.1 1 0.130

50370981 Wasatch-Green River Coalbed Gas Southwestern Wyoming 2002 0.02 0.1 0.8 0.124

50311081 Fort Union Coalbed Gas Williston Basin 2008 0.02 0.085 1 0.114

50330183 Lower Fort Union-Lance Formations Powder River Basin 2000 0.02 0.085 1 0.114

50340282 Fort Union Formation Coalbed Gas Big Horn Basin 2008 0.02 0.08 1 0.109

50370581 Mesaverde Coalbed Gas Southwestern Wyoming 2002 0.02 0.06 2 0.106

50370681 Mesaverde Coalbed Gas Southwestern Wyoming 2002 0.02 0.06 2 0.106

50470381 Wilcox Coalbed Gas Gulf Coast Cenozoic 2007 0.01 0.05 0.5 0.065

53000281 Rio Escondido Basin Olmos Coalbed Gas Burgos Basin 2007 0.01 0.03 0.3 0.039

50640481 Desmoinesian-Virgilian Coalbed Gas Illinois Basin 2007 0.01 0.03 0.25 0.037

50470281 Cretaceous Olmos Coalbed Gas Gulf Coast Cenozoic 2007 0.01 0.03 0.1 0.032
24 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

Table 12. Input data for estimated ultimate recovery distributions for United States tight-gas assessment units, values in billions of 

cubic feet of natural gas.

[AU, assessment unit; EUR, estimated ultimate recovery]

AU

number AU name Province Yearassessed

Minimum

EUR

Median

EUR

Maximum

EUR

Mean

EUR

50370661 Mesaverde-Lance-Fort Union Continuous Gas Southwestern Wyoming 2002 0.02 1.2 15 1.657

50370561 Almond Continuous Gas Southwestern Wyoming 2002 0.02 0.9 20 1.460

50200261 Uinta Basin Continuous Gas Uinta-Piceance 2000 0.02 0.5 40 1.293

50030161 Tuxedni-Naknek Continuous Gas Southern Alaska 2011 0.02 0.6 30 1.286

50620161 Arkoma-Ouachita Foredeep Continuous Arkoma Basin 2010 0.02 0.6 30 1.286

50350261 Frontier-Muddy Continuous Gas Wind River Basin 2005 0.02 0.7 15 1.123

50370261 Mowry Continuous Gas Southwestern Wyoming 2002 0.02 0.7 15 1.123

50350265 Lance-Fort Union Sandstone Gas Wind River Basin 2005 0.02 0.6 20 1.110

50370861 Lance-Fort Union Continuous Gas Southwestern Wyoming 2002 0.02 0.8 10 1.104

50370761 Lewis Continuous Gas Southwestern Wyoming 2002 0.02 0.6 15 1.009

50200362 Uinta Basin Continuous Gas Uinta-Piceance 2000 0.02 0.5 16 0.911

50200263 Piceance Basin Continuous Gas Uinta-Piceance 2000 0.02 0.5 15 0.892

50350264 Mesaverde-Meeteetse Sandstone Gas Wind River Basin 2005 0.02 0.5 15 0.892

50350262 Cody Sandstones Continuous Gas Wind River Basin 2005 0.02 0.4 20 0.855

50670364 Tuscarora Basin Center Appalachian Basin 2002 0.01 0.7 4 0.817

50220261 Lewis Continuous Gas San Juan Basin 2002 0.02 0.5 6 0.683

50220361 Mesaverde Central-Basin Continuous Gas San Juan Basin 2002 0.02 0.5 6 0.683

50220363 Dakota-Greenhorn Continuous Gas San Juan Basin 2002 0.02 0.4 8 0.627

50370461 Hilliard-Baxter-Mancos Continuous Gas Southwestern Wyoming 2002 0.02 0.4 8 0.627

50700261 Richmond Basin Continuous Gas Atlantic Coastal Plain 2011 0.02 0.4 8 0.627

50700461 Deep River Basin Continuous Gas Atlantic Coastal Plain 2011 0.02 0.4 8 0.627

50200161 Deep (6,000 feet plus) Coal and Sandstone Gas Uinta-Piceance 2000 0.2 0.5 4 0.617

50200262 Uinta Basin Transitional Gas Uinta-Piceance 2000 0.02 0.25 15 0.570

50340261 Muddy-Frontier Sandstone and Mowry 

Fractured Shale Continuous Gas

Big Horn Basin 2008 0.02 0.35 7.5 0.560

50220362 Mancos Sandstones Continuous Gas San Juan Basin 2002 0.02 0.35 5 0.499

50370562 Rock Springs-Ericson Continuous Gas Southwestern Wyoming 2002 0.02 0.4 3 0.491

50200361 Piceance Basin Continuous Gas Uinta-Piceance 2000 0.02 0.25 10 0.490

50280163 Eagle Sandstone and Claggett Shale West North-Central Montana 2000 0.01 0.25 9 0.475

50220161 Pictured Cliffs Continuous Gas San Juan Basin 2002 0.02 0.25 7 0.434

50280162 Eagle Sandstone and Claggett Shale East North-Central Montana 2000 0.01 0.2 7 0.375

50200363 Uinta-Piceance Transitional and Migrated Gas Uinta-Piceance 2000 0.02 0.2 7 0.373

50200264 Piceance Basin Transitional Gas Uinta-Piceance 2000 0.02 0.25 4 0.367

50280166 Greenhorn-Upper Belle Fourche North-Central Montana 2000 0.01 0.2 6 0.356

50280167 Bowdoin Dome North-Central Montana 2000 0.01 0.2 5 0.336

50340263 Cody Sandstone Continuous Gas Big Horn Basin 2008 0.02 0.2 5 0.334

50340264 Mesaverde Sandstone Continuous Gas Big Horn Basin 2008 0.02 0.2 5 0.334

50700161 Taylorsville Basin Continuous Gas Atlantic Coastal Plain 2011 0.02 0.2 5 0.334

50700361 South Newark Basin Continuous Gas Atlantic Coastal Plain 2011 0.02 0.2 5 0.334

50280165 Greenhorn-Lower Belle Fourche North-Central Montana 2000 0.01 0.25 2.5 0.327

50050161 Columbia Basin Continuous Gas Eastern OregonWashington2006 0.02 0.2 3 0.288

50390662 Dakota Group Basin-Center Gas Denver Basin 2001 0.02 0.2 2.5 0.275

50670461 Greater Big Sandy Appalachian Basin 2002 0.01 0.15 2 0.210

50701061 Dan River-Danville Basin Continuous Gas Atlantic Coastal Plain 2011 0.02 0.1 2.5 0.165

50330461 Shallow Continuous Biogenic Gas Powder River Basin 2002 0.01 0.08 1.5 0.122

50670361 Clinton-Medina Basin Center Appalachian Basin 2002 0.01 0.08 1.2 0.115

50670465 Catskill Sandstones and Siltstones Appalachian Basin 2002 0.01 0.07 1.5 0.111

50280161 Judith River Formation North-Central Montana 2000 0.01 0.06 2 0.109

50280164 Niobrara-Carlile North-Central Montana 2000 0.01 0.07 1 0.099

50670363 Clinton-Medina Transitional Appalachian Basin 2002 0.01 0.06 1 0.089

50670362 Clinton-Medina Transitional Northeast Appalachian Basin 2002 0.01 0.06 0.9 0.086

50670466 Berea Sandstone Appalachian Basin 2002 0.01 0.03 0.5 0.044
Tables 25

Table 13. Input data for estimated ultimate recovery distributions for United States continuous-oil assessment units, values in millions 

of barrels of oil.

[AU, assessment unit; EUR, estimated ultimate recovery]

AU

number

AU

name

Province Year

assessed

Minimum

EUR

Median

EUR

Maximum

EUR

Mean

EUR

50310164 Eastern Expulsion Threshold Williston Basin 2008 0.002 0.12 5 0.241

50310163 Nesson-Little Knife Structural Williston Basin 2008 0.002 0.09 4 0.185

50210361 Cane Creek Shale Oil Paradox Basin 2011 0.002 0.08 3 0.154

50310165 Northwest Expulsion Threshold Williston Basin 2008 0.002 0.065 4 0.151

50310161 Elm Coulee-Billings Nose Williston Basin 2008 0.002 0.08 2 0.135

50270561 Marias River Shale Continuous Oil Montana

Thrust Belt

2002 0.001 0.08 1.6 0.126

50370361 Niobrara Continuous Oil Southwestern

Wyoming

2002 0.001 0.08 1.6 0.126

50300361 Niobrara Continuous Oil Hanna, Laramie, 

Shirley Basins

2005 0.001 0.04 1.6 0.079

50310162 Central Basin-Poplar Dome Williston Basin 2008 0.002 0.025 2 0.064

50210363 Gothic, Chimney Rock, Hovenweep Shale Oil Paradox Basin 2011 0.002 0.03 1.5 0.064

50580162 Woodford Shale Oil Anadarko Basin 2010 0.003 0.03 1.5 0.064

50200561 Deep Uinta Overpressured Continuous Oil Uinta-Piceance 2000 0.003 0.045 0.45 0.059

50440165 Spraberry Continuous Oil Permian Basin 2007 0.001 0.045 0.4 0.057

50490170 Eagle Ford Shale Oil Gulf Coast

Mesozoic

2010 0.002 0.03 1 0.055

50490168 Austin Pearsall-Giddings Area Oil Gulf Coast

Mesozoic

2010 0.002 0.04 0.5 0.055

50330361 Niobrara Continuous Oil Powder River

Basin

2002 0.002 0.028 0.5 0.042

50330261 Mowry Continuous Oil Powder River

Basin

2002 0.002 0.025 0.35 0.035

50340262 Mowry Fractured Shale Continuous Oil Big Horn Basin 2008 0.002 0.025 0.35 0.035

50390261 Fractured Niobrara Limestone (Silo Field Area) Denver Basin 2001 0.002 0.022 0.4 0.033

50390661 Niobrara-Codell (Wattenberg Area) Denver Basin 2001 0.003 0.008 0.1 0.011
26 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

References Cited

Charpentier, R.R., and Cook, T.A., 2010, Improved USGS 

methodology for assessing continuous petroleum resources: 

U.S. Geological Survey Data Series 547, 22 p. and program, 

http://pubs.usgs.gov/ds/547/.

Crovelli, R.A., 2000, Analytical resource assessment method 

for continuous (unconventional) oil and gas accumulations—

The “ACCESS” Method: U.S. Geological Survey Open-File 

Report 00–044, 34 p., http://pubs.er.usgs.gov/publication/

ofr0044.

Crovelli, R.A., 2012, Analytical resource assessment method 

for continuous (unconventional) oil and gas accumulations—

The “ACCESS” Method: U.S. Geological Survey Open-File 

Report 2012–1146, 32 p., http://pubs.usgs.gov/of/2012/1146. 

[Revised by Charpentier, R.R.]

Klett, T.R., and Charpentier, R.R., 2003, FORSPAN model users 

guide: U.S. Geological Survey Open-File Report 03–354, 37 

p., http://pubs.usgs.gov/of/2003/ofr-03-354/.

Klett, T.R., and Schmoker, J.W., 2003, U.S. Geological Survey 

input-data form and operational procedure for the assessment 

of continuous petroleum accumulations, chap. 18 of USGS 

Uinta-Piceance Assessment Team, Petroleum systems and 

geologic assessment of oil and gas in the Uinta-Piceance Province, Utah and Colorado: U.S. Geological Survey Digital Data 

Series DDS–69–B, 8 p., http://pubs.usgs.gov/dds/dds-069/

dds-069-b/REPORTS/Chapter_18.pdf.

Schmoker, J.W., 2003, U.S. Geological Survey assessment 

concepts for continuous petroleum accumulations, chap. 17 of 

USGS Uinta-Piceance Assessment Team, Petroleum systems 

and geologic assessment of oil and gas in the Uinta-Piceance 

Province, Utah and Colorado: U.S. Geological Survey Digital 

Data Series DDS–69–B, 7 p., http://pubs.usgs.gov/dds/

dds-069/dds-069-b/REPORTS/Chapter_17.pdf.

U.S. Geological Survey Oil and Gas Assessment Team, 2012, 

Variability of distributions of well-scale estimated ultimate 

recovery for continuous (unconventional) oil and gas resources 

in the United States: U.S. Geological Survey Open-File Report 

2012–1118, 18 p., http://pubs.usgs.gov/of/2012/1118/.
Appendix 1 27

Appendix 1. Publications Presenting Results of Assessments Used in this Report

U.S. Geological Survey Powder River Basin Assessment 

Team., 2009, Total petroleum systems and geologic assessment of oil and gas resources in the Powder River Basin 

Province, Wyoming and Montana: U.S. Geological Survey 

Digital Data Series DDS–69–U, 3 chapters, 1 CD-ROM, 

http://pubs.usgs.gov/dds/dds-069/dds-069-u/. [Revised 

April 2010]

U.S. Geological Survey Powder River Basin Province Assessment Team, 2004, Total petroleum system and assessment 

of coalbed gas in the Powder River Basin Province, Wyoming and Montana: U.S. Geological Survey Digital Data 

Series DDS–69-C, 1 CD-ROM, http://pubs.usgs.gov/dds/

dds-069/dds-069-c/.

U.S. Geological Survey San Juan Basin Assessment Team, 2013, 

Total petroleum systems and geologic assessment of undiscovered oil and gas resources in the San Juan Basin Province, 

exclusive of Paleozoic rocks, New Mexico and Colorado: 

U.S. Geological Survey Digital Data Series 69–F, 7 chapters, variously paged, 1 CD-ROM, http://pubs.usgs.gov/dds/

dds-069/dds-069-f/.

U.S. Geological Survey Southwestern Wyoming Province 

Assessment Team, 2005, Petroleum systems and geologic 

assessment of oil and gas in the Southwestern Wyoming 

Province, Wyoming, Colorado and Utah: U.S. Geological Survey Digital Data Series DDS–69-D, 1 CD-ROM, 

http://pubs.usgs.gov/dds/dds-069/dds-069-d/.

U.S. Geological Survey Uinta-Piceance Assessment Team, 

compilers, 2003, Petroleum systems and geologic assessment of oil and gas in the Uinta-Piceance Province, Utah 

and Colorado: U.S. Geological Survey Digital Data Series 

DDS–69-B, 1 CD-ROM, http://pubs.usgs.gov/dds/dds-069/

dds-069-b/.

U.S. Geological Survey Western Gulf Province Assessment 

Team, 2006, Petroleum systems and geologic assessment 

of undiscovered oil and gas, Navarro and Taylor Groups, 

Western Gulf Province, Texas: U.S. Geological Survey 

Digital Data Series DDS–69-H, 4 chapters, 1 CD-ROM, 

http://pubs.usgs.gov/dds/dds-069/dds-069-h/.

U.S. Geological Survey Western Oregon and Washington 

Province Assessment Team, 2011, Geologic assessment 

of undiscovered hydrocarbon resources of the Western 

Oregon and Washington Province: U.S. Geological Survey 

Digital Data Series DDS–69–X, 4 chapters 1 CD-ROM, 

http://pubs.usgs.gov/dds/dds-069/dds-069-x/.

CD-ROMs

Higley, D.K., compiler, 2007, Petroleum systems and assessment of undiscovered oil and gas in the Raton Basin–Sierra 

Grande Uplift Province, Colorado and New Mexico—USGS 

Province 41: U.S. Geological Survey Digital Data Series 

DDS–69–N, 141 p.,1 CD-ROM, http://pubs.usgs.gov/dds/

dds-069/dds-069-n/.

Higley, D.K., compiler, 2007, Petroleum systems and assessment 

of undiscovered oil and gas in the Denver Basin Province, 

Colorado, Kansas, Nebraska, South Dakota, and Wyoming—

USGS Province 39: U.S. Geological Survey Digital Data 

Series DDS–69–P., 1 CD-ROM, http://pubs.usgs.gov/dds/

dds-069/dds-069-p/.

Roberts, S.B., compiler, 2008, Geologic assessment of undiscovered, technically recoverable coalbed-gas resources in 

Cretaceous and Tertiary rocks, North Slope and adjacent State 

waters, Alaska: U.S. Geological Survey Digital Data Series 

DDS–69–S, 4 chapters, 1 CD-ROM, http://pubs.usgs.gov/

dds/dds-069/dds-069-s/.

U.S. Geological Survey Bighorn Basin Assessment Team, 

2010, Petroleum systems and geologic assessment of oil and 

gas in the Bighorn Basin Province, Wyoming and Montana: 

U.S. Geological Survey Digital Data Series DDS–69–V, 8 

chapters, pages variable, 1 CD-ROM, http://pubs.usgs.gov/

dds/dds-069/dds-069-v/.

U.S. Geological Survey Black Warrior Basin Province Assessment Team, 2007, Geologic assessment of undiscovered 

oil and gas resources of the Black Warrior Basin Province, 

Alabama and Mississippi: U.S. Geological Survey Digital 

Data Series DDS-69-I, 5 chapters, 76 pages, 1 CD-ROM, 

http://pubs.usgs.gov/dds/dds-069/dds-069-i/.

U.S. Geological Survey Eastern Oregon and Washington 

Province Assessment Team, 2008, Geologic assessment of 

undiscovered gas resources of the Eastern Oregon and Washington Province: U.S. Geological Survey Digital Data Series 

DDS–69-O, 5 chapters, 1 CD-ROM, http://pubs.usgs.gov/

dds/dds-069/dds-069-o/.

U.S. Geological Survey Hanna, Laramie, and Shirley Basins 

Province Assessment Team, 2007, Petroleum systems and 

geologic assessment of undiscovered oil and gas, Hanna, 

Laramie, and Shirley Basins Province, Wyoming and 

Colorado: U.S. Geological Survey Digital Data Series 

DDS–69–K, 1 CD-ROM, http://pubs.usgs.gov/dds/dds-069/

dds-069-k/.
28 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

U.S. Geological Survey Williston Basin Province Assessment Team, 2011, Assessment of undiscovered oil and gas 

resources of the Williston Basin Province of North Dakota, 

Montana, and South Dakota, 2010: U.S. Geological Survey 

Digital Data Series DDS–69–W, 7 chapters, 1 CD-ROM, 

http://pubs.usgs.gov/dds/dds-069/dds-069-w/.

U.S. Geological Survey Wind River Basin Province Assessment Team, 2007, Petroleum systems and geologic assessment of oil and gas in the Wind River Basin Province, 

Wyoming: U.S. Geological Survey Digital Data Series 

DDS–69–J, 1 CD-ROM, http://pubs.usgs.gov/dds/dds-069/

dds-069-j/.

Fact Sheets

Anna, L.O., Charpentier, R.R., Cook, T.A., Klett, T.R., 

Pollastro, R.M., and Schenk, C.J., 2006, Assessment of 

undiscovered oil and gas resources of the Powder River 

Basin Province of Wyoming and Montana—2006 update: 

U.S. Geological Survey Fact Sheet 2006–3135, 2 p., 

http://pubs.usgs.gov/fs/2006/3135/.

Anna, L.O., Pollastro, R.M., Gaswirth, S.B., Lewan, M.D., 

Lillis, P.G., Roberts, L.N.R., Schenk, C.J., Charpentier, 

R.R., Cook, T.A., and Klett, T.R., 2008, Assessment of 

undiscovered oil and gas resources of the Williston Basin 

Province of North Dakota, Montana, and South Dakota, 

2008: U.S. Geological Survey Fact Sheet 2008–3092, 2 p., 

http://pubs.usgs.gov/fs/2008/3092/.

Brownfield, M.E., Charpentier, R.R., Cook, T.A., Klett, T.R., 

Pollastro, R.M., and Schenk, C.J., 2009, Assessment of 

undiscovered hydrocarbon resources of the Western Oregon 

and Washington Province: U.S. Geological Survey Fact 

Sheet 2009–3060, 2 p., http://pubs.usgs.gov/fs/2009/3060/.

Brownfield, M.E., Tennyson, M.E., Ahlbrandt, T.S., 

Charpentier, R.R., Cook, T.A., Klett, T.R., Pollastro, R.M., 

and Schenk, C.J., 2006, Assessment of undiscovered gas 

resources of the Eastern Oregon and Washington Province, 

2006: U.S. Geological Survey Fact Sheet 2006–3091, 2 p., 

http://pubs.usgs.gov/fs/2006/3091/.

Coleman, J.L., Milici, R.C., Cook, T.A., Charpentier, R.R., 

Kirschbaum, Mark, Klett, T.R., Pollastro, R.M., and 

Schenk, C.J., 2011, Assessment of undiscovered oil and gas 

resources of the Devonian Marcellus Shale of the Appalachian Basin Province, 2011: U.S. Geological Survey Fact 

Sheet 2011–3092, 2 p., http://pubs.usgs.gov/fs/2011/3092/.

Coleman, J.L., Swezey, C.S., Ryder, R.T., Charpentier, R.R., 

Milici, R.C., Hatch, J.R., Cook, T.A., Klett, T.R., Pollastro, 

R.M., Schenk, C.J., and Schmoker, J.W., 2006, Undiscovered oil and gas resources underlying the U.S. portions of 

the Great Lakes, 2005: U.S. Geological Survey Fact Sheet 

2006–3049, 4 p., http://pubs.usgs.gov/fs/2006/3049/.

Dubiel, R.F., Pitman, J.K., Pearson, O.N., Pearson, Krystal, 

Kinney, S.A., Lewan, M.D., Burke, Lauri, Biewick, L.R.H., 

Charpentier, R.R., Cook, T.A., Klett, T.R., Pollastro, R.M., 

and Schenk, C.J., 2012, Assessment of undiscovered oil 

and gas resources in conventional and continuous petroleum systems in the Upper Cretaceous Eagle Ford Group, 

U.S. Gulf Coast Region, 2011: U.S. Geological Survey Fact 

Sheet 2012–3003, 2 p., http://pubs.usgs.gov/fs/2012/3003/.

Dubiel, R.F., Pitman, J.K., Pearson, O.N., Warwick, P.D., 

Karlsen, A.W., Coleman, J.L., Hackley, P.C., Hayba, D.O., 

Swanson, S.M., Charpentier, R.R., Cook, T.A., Klett, 

T.R., Pollastro, R.M., and Schenk, C.J., 2007, Assessment 

of undiscovered oil and gas resources in Tertiary strata 

of the Gulf Coast, 2007: U.S. Geological Survey Fact 

Sheet 2007–3066, 4 p., http://pubs.usgs.gov/fs/2007/3066/.

Dubiel, R.F., Warwick, P.D., Swanson, Sharon, Burke, Lauri, 

Biewick, L.R.H., Charpentier, R.R., Coleman, J.L., Cook, 

T.A., Dennen, Kris, Doolan, Colin, Enomoto, Catherine, 

Hackley, P.C., Karlsen, A.W., Klett, T.R., Kinney, S.A., 

Lewan, M.D., Merrill, Matt, Pearson, Krystal, Pearson, 

O.N., Pitman, J.K., Pollastro, R.M., Rowan, E.L., Schenk, 

C.J., and Valentine, Brett, 2011, Assessment of undiscovered oil and gas resources in Jurassic and Cretaceous strata 

of the Gulf Coast, 2010: U.S. Geological Survey Fact Sheet 

2011–3020, 4 p., http://pubs.usgs.gov/fs/2011/3020/.

Dyman, T.S., Condon, S.M., Ahlbrandt, T.S., Charpentier, 

R.R., Cook, T.A., Klett, T.R., Lewan, M.D., Lillis, P.G., 

Pawlewicz, M.J., Pollastro, R.M., and Schenk, C.J., 2006, 

2005 assessment of undiscovered oil and gas resources 

in Hanna, Laramie, Shirley Basins Province, Wyoming: 

U.S. Geological Survey Fact Sheet 2005-3125, 2 p., 

http://pubs.usgs.gov/fs/2005/3125/.

Flores, R.M., Anna, L.O., Dolton, G.L., Fox, J.E., French, 

C.D., Charpentier, R.R., Cook, T.A., Crovelli, R.A., Klett, 

T.R., Pollastro, R.M., and Schenk, C.J., 2002, Assessment 

of undiscovered oil and gas resources of the Powder River 

Basin Province of Wyoming and Montana, 2002: U.S. Geological Survey Fact Sheet 146–02, 2 p, http://pubs.usgs.gov/

fs/fs-146-02/.

Hatch, J.R., Pawlewicz, M.J., Charpentier, R.R., Cook, T.A., 

Crovelli, R.A., Klett, T.R., Pollastro, R.M., and Schenk, C.J., 

2003, Assessment of undiscovered oil and gas resources 

of the Black Warrior Basin Province, 2002: U.S. Geological Survey Fact Sheet 038-03, 2 p., http://pubs.usgs.gov/fs/

fs-038-03/.

Higley, Debra, Charpentier, R.R., Cook, Troy, Klett, T.R., 

Pollastro, Richard, Schmoker, J.W., and Schenk, C.J., 2003, 

2002 USGS assessment of oil and gas resource potential of 

the Denver Basin Province of Colorado, Kansas, Nebraska, 

South Dakota, and Wyoming: U.S. Geological Survey Fact 

Sheet 002–03, 4 p., http://pubs.usgs.gov/fs/fs-002-03/.
Appendix 1 29

Higley, D.K., Cook, T.A., Pollastro, R.M., Charpentier, R.R., 

Klett, T.R., and Schenk, C.J., 2005, Assessment of undiscovered oil and gas resources of the Raton Basin–Sierra 

Grande Uplift Province of New Mexico and Colorado, 

2004: U.S. Geological Survey Fact Sheet 2005–3027, 2 p., 

http://pubs.usgs.gov/fs/2005/3027/.

Higley, D.K., Gaswirth, S.B., Abbott, M.M., Charpentier, 

R.R., Cook, T.A., Ellis, G.S., Gianoutsos, N.J., Hatch, J.R., 

Klett, T.R., Nelson, Philip, Pawlewicz, M.J., Pearson, O.N., 

Pollastro, R.M., and Schenk, C.J., 2011, Assessment of 

undiscovered oil and gas resources of the Anadarko Basin 

Province of Oklahoma, Kansas, Texas, and Colorado, 

2010: U.S. Geological Survey Fact Sheet 2011–3003, 2 p., 

http://pubs.usgs.gov/fs/2011/3003/.

Houseknecht, D.W., Coleman, J.L., Milici, R.C., Garrity, C.P., 

Rouse, W.A., Fulk, B.R., Paxton, S.T., Abbott, M.M., Mars, 

J.C., Cook, T.A., Schenk, C.J., Charpentier, R.R., Klett, 

T.R., Pollastro, R.M., and Ellis, G.S., 2010, Assessment of 

undiscovered natural gas resources of the Arkoma Basin 

Province and geologically related areas: U.S. Geological 

Survey Fact Sheet 2010–3043, 4 p., http://pubs.usgs.gov/

fs/2010/3043/.

Kirschbaum, M.A., Anna, Larry, Collett, T.S., Cook, Troy, 

Dubiel, R.F., Finn, T.M., Hettinger, R.D., Henry, Mitchell, 

Johnson, E.A., Johnson, R.C., Lillis, P.G., Nelson, P.H., 

Nuccio, V.F., Rice, C.A., Roberts, L.N.R., and Roberts, 

S.B., 2002, Assessment of undiscovered oil and gas 

resources of the Uinta-Piceance Province of Colorado and 

Utah, 2002: U.S. Geological Survey Fact Sheet 026–02, 

2 p., http://pubs.usgs.gov/fs/fs-0026-02/.

Kirschbaum, M.A., Anna, Larry, Collett, T.S., Cook, Troy, 

Dubiel, R.F., Finn, T.M., Hettinger, R.D., Henry, Mitchell, 

Johnson, E.A., Johnson, R.C., Lillis, P.G., Nelson, P.H., 

Nuccio, V.F., Rice, C.A., Roberts, L.N.R., and Roberts, 

S.B., 2003, Assessment of undiscovered oil and gas 

resources of the Uinta-Piceance Province of Colorado and 

Utah, 2002: U.S. Geological Survey Fact Sheet 157–02, 

2 p., http://pubs.usgs.gov/fs/fs-157-02/.

Kirschbaum, M.A., Charpentier, R.R., Crovelli, R.A., Klett, 

T.R., Pollastro, R.M., and Schenk, C.J., 2004, Assessment 

of undiscovered oil and gas resources of the Wyoming 

Thrust Belt Province, 2003: U.S. Geological Survey Fact 

Sheet 2004–3025, 2 p., http://pubs.usgs.gov/fs/2004/3025/.

Kirschbaum, M.A., Condon, S.M., Finn, T.M., Johnson, R.C., 

Lillis, P.G., Nelson, P.H., Roberts, L.N.R., Roberts, S.B., 

Charpentier, R.R., Cook, Troy, Klett, T.R., Pollastro, R.M., 

and Schenk, C.J., 2008, Assessment of undiscovered oil 

and gas resources of the Bighorn Basin Province, Wyoming and Montana, 2008: U.S. Geological Survey Fact 

Sheet 2008–3050, 2 p., http://pubs.usgs.gov/fs/2008/3050/.

Kirschbaum, Mark, Finn, T.M., Hettinger, R.D., Johnson, 

E.A., Johnson, R.C., Kibler, Joyce, Lillis, P.G., Nelson, 

P.H., Roberts, L.N.R., Roberts, S.B., Charpentier, R.R., 

Cook, T.A., Crovelli, R.A., Klett, T.R., Pollastro, R.M., 

and Schenk, C.J., 2002, Assessment of undiscovered oil 

and gas resources of the Southwestern Wyoming Province, 

2002: U.S. Geological Survey Fact Sheet 145–02, 2 p., 

http://pubs.usgs.gov/fs/fs-145-02/.

Kirschbaum, M.A., Finn, T.M., Johnson, R.C., Kibler, Joyce, 

Lillis, P.G., Nelson, P.H., Roberts, L.N.R., Roberts, S.B., 

Charpentier, R.R., Cook, Troy, Klett, T.R., Pollastro, R.M., 

and Schenk, C.J., 2005, Assessment of undiscovered oil 

and gas resources of the Wind River Basin Province, 

2005: U.S. Geological Survey Fact Sheet 2005–3141, 2 p., 

http://pubs.usgs.gov/fs/2005/3141/.

Milici, R.C., Coleman, J.L., Rowan, E.L., Cook, T.A., 

Charpentier, R.R., Kirschbaum, M.A., Klett, T.R., Pollastro, 

R.M., and Schenk, C.J., 2012, Assessment of undiscovered 

oil and gas resources of the East Coast Mesozoic basins 

of the Piedmont, Blue Ridge Thrust Belt, Atlantic Coastal 

Plain, and New England Provinces, 2011: U.S. Geological 

Survey Fact Sheet 2012–3075, 2 p., http://pubs.usgs.gov/

fs/2012/3075/.

Milici, R.C., and Hatch, J.R., 2004, Assessment of undiscovered Carboniferous coal-bed gas resources of the 

Appalachian Basin and Black Warrior Basin Provinces, 

2002: U.S. Geological Survey Fact Sheet 2004–3092, 2 p., 

http://pubs.usgs.gov/fs/2004/3092/.

Milici, R.C., Ryder, R.T., Swezey, C.S., Charpentier, R.R., 

Cook, T.A., Crovelli, R.A., Klett, T.R., Pollastro, R.M., 

and Schenk, C.J., 2003, Assessment of undiscovered oil 

and gas resources of the Appalachian Basin Province, 

2002: U.S. Geological Survey Fact Sheet 009–03, 2 p., 

http://pubs.usgs.gov/fs/fs-009-03/.

Pearson, Krystal, Dubiel, R.F., Pearson, O.N., Pitman, J.K., 

Charpentier, R.R., Cook, T.A., Klett, T.R., Pollastro, R.M., and 

Schenk, C.J., 2011, Assessment of undiscovered oil and gas 

resources of the Upper Cretaceous Austin Chalk and Tokio 

and Eutaw Formations, Gulf Coast, 2010: U.S. Geological 

Survey Fact Sheet 2011–3046, 2 p., http://pubs.usgs.gov/

fs/2011/3046/.

Pollastro, R.M., Cook, T.A., Roberts, L.N.R., Schenk, C.J., 

Lewan, M.D., Anna, L.O., Gaswirth, S.B., Lillis, P.G., Klett, 

T.R., and Charpentier, R.R., 2008, Assessment of undiscovered 

oil resources in the Devonian-Mississippian Bakken Formation, Williston Basin Province, Montana and North Dakota, 

2008: U.S. Geological Survey Fact Sheet 2008–3021, 2 p., 

http://pubs.usgs.gov/fs/2008/3021/.
30 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

Pollastro, R.M., Hill, R.J., Ahlbrandt, T.A., Charpentier, R.R., 

Cook, T.A., Klett, T.R., Henry, M.E., and Schenk, C.J., 

2004, Assessment of undiscovered oil and gas resources of 

the Bend Arch-Fort Worth Basin Province of north-central 

Texas and southwestern Oklahoma, 2003: U.S. Geological 

Survey Fact Sheet 2004–3022, 2 p., http://pubs.usgs.gov/

fs/2004/3022/.

Ridgley, J.L., Anna, L.O., Condon, S.M., Fishman, N.S., 

Hester, T.C., Lillis, P.G., Rowan, E.L., Charpentier, R.R., 

Cook, T.A., Crovelli, R.A., Klett, T.R., and Schenk, C.J., 

2008, Assessment of undiscovered biogenic gas resources, 

North-Central Montana Province: U.S. Geological Survey Fact Sheet 2008–3036, 2 p., http://pubs.usgs.gov/

fs/2008/3036/.

Ridgley, J.L., Condon, S.M., Dubiel, R.F., Charpentier, R.R., 

Cook, T.A., Crovelli, R.A., Klett, T.R., Pollastro, R.M., 

and Schenk, C.J., 2002, Assessment of undiscovered oil 

and gas resources of the San Juan Basin Province of New 

Mexico and Colorado, 2002: U.S. Geological Survey Fact 

Sheet 147–02, 2 p., http://pubs.usgs.gov/fs/fs-147-02/.

Roberts, Steve, Barker, C.E., Bird, K.J., Charpentier, R.R., 

Cook, Troy, Houseknecht, D.W., Klett, T.R., Pollastro, 

R.M., and Schenk, C.J., 2006, Assessment of coalbed 

gas resources in Cretaceous and Tertiary rocks on the 

North Slope, Alaska, 2006: U.S. Geological Survey Fact 

Sheet 2006–3105, 2 p., http://pubs.usgs.gov/fs/2006/3105/.

Schenk, C.J., Charpentier, R.R., Cook, T.A., Dyman, T.S., 

French, C.D., Henry, M.E., Klett, T.R., Perry, W.J., Pollastro, R.M., and Potter, C.J., 2002, Assessment of undiscovered oil and gas resources of the Montana Thrust Belt 

Province, 2002: U.S. Geological Survey Fact Sheet 148–02, 

2 p., http://pubs.usgs.gov/fs/fs-148-02/.

Schenk, C.J., Pollastro, R.M., Cook, T.A., Pawlewicz, M.J., 

Klett, T.R., Charpentier, R.R., and Cook, H.E., 2008, 

Assessment of undiscovered oil and gas resources of the 

Permian Basin Province of west Texas and southeast New 

Mexico, 2007: U.S. Geological Survey Fact Sheet 2007–

3115, 4 p., http://pubs.usgs.gov/fs/2007/3115/.

Stanley, R.G., Ahlbrandt, T.S., Charpentier, R.R., Cook, T.A., 

Crews, J.M., Klett, T.R.; Lillis, P.G., Morin, R.L., Phillips, 

J.D., Pollastro, R.M., Rowan, E.L., Saltus, R.W., Schenk, 

C.J., Simpson, M.K., Till, A.B., and Troutman, S.M., 2004, 

Oil and gas assessment of Yukon Flats, east-central Alaska, 

2004: U.S. Geological Survey Fact Sheet 2004–3121, 2 p., 

http://pubs.usgs.gov/fs/2004/3121/.

Stanley, R.G., Charpentier, R.R., Cook, T.A., Houseknecht, 

D.W., Klett, T.R., Lewis, K.A., Lillis, P.G., Nelson, P.H., 

Phillips, J.D., Pollastro, R.M., Potter, C.J., Rouse, W.A., 

Saltus, R.W., Schenk, C.J., Shah, A.K., and Valin, Z.C., 

2011, Assessment of undiscovered oil and gas resources 

of the Cook Inlet region, south-central Alaska, 2011: 

U.S. Geological Survey Fact Sheet 2011–3068, 2 p., 

http://pubs.usgs.gov/fs/2011/3068/.

Swezey, C.S., Hatch, J.R., Brennan, S.T., East, J.A., Rowan, 

E.L., Repetski, J.E., Charpentier, R.R., Cook, T.A., Klett, 

T.R., Pollastro, R.M., and Schenk, C.J., 2007, Assessment 

of undiscovered oil and gas resources of the Illinois Basin, 

2007: U.S. Geological Survey Fact Sheet 2007–3058, 2 p., 

http://pubs.usgs.gov/fs/2007/3058/.

Swezey, C.S., Hatch, J.R., Hayba, D.O., Repetski, J.E., 

Charpentier, R.R., Cook, T.A., Klett, T.R., Pollastro, R.M., 

and Schenk, C.J., 2005, Assessment of undiscovered oil and 

gas resources of the U.S. portion of the Michigan Basin, 

2004: U.S. Geological Survey Fact Sheet 2005–3070, 2 p., 

http://pubs.usgs.gov/fs/2005/3070/.

Warwick, P.D., Charpentier, R.R., Cook, T.A., Klett, T.R., 

Pollastro, R.M., and Schenk, C.J., 2007, Assessment of 

undiscovered oil and gas resources in Cretaceous-Tertiary 

coal beds of the Gulf Coast Region, 2007: U.S. Geological 

Survey Fact Sheet 2007–3039, 2 p., http://pubs.usgs.gov/

fs/2007/3039/.

Whidden, K.J., Anna, L.O., Pearson, K.M., Lillis, P.G., 

Charpentier, R.R., Cook, T.A., Klett, T.R., Pollastro, 

R.M., Dubiel, R.F., and Schenk, C.J., 2012, Assessment of 

undiscovered oil and gas resources in the Paradox Basin 

Province, Utah, Colorado, New Mexico, and Arizona, 

2011: U.S. Geological Survey Fact Sheet 2012–3031, 4 p., 

http://pubs.usgs.gov/fs/2012/3031/.
Appendix 2 31

Appendix 2. Structure of the Files Presented in this Report

Katz, B.J., and Liro, L.M., 1993, The Waltman Shale 

Member, Fort Union Formation, Wind River Basin—A 

Paleocene clastic lacustrine source system, in Keefer, 

W.R., Metzger, W.J., and Godwin, L.H., eds., Wyoming 

Geological Association Special Symposium on Oil and 

Gas and Other Resources of the Wind River Basin, 

Wyoming, 1993: Wyoming Geological Association, 

Casper, Wyoming, p. 163–174. 

16. Notes from Assessor 2: additional explanatory notes.

17. AU Type: assessment unit type, the primary commodity 

type in the assessment unit, based on the gas-to-oil ratio 

(GOR) of the petroleum endowment, which includes both 

the discovered and undiscovered petroleum. An assessment unit is characterized as being oil prone if the GOR 

is less than 20,000 cubic feet of gas per barrel of oil; 

otherwise, it is gas prone.

18. Minimum Total Recovery: minimum total recovery per 

cell considered for assessment, in million barrels of oil 

(MMBO) for oil assessment units or billion cubic feet of 

gas (BCFG) for gas assessment units.

19. Number of Tested Cells: number of tested cells in the 

assessment unit.

20. Number of Tested Cells > Minimum: number of tested 

cells in the assessment unit that have total recoveries 

equal to or larger than the specified minimum total recovery per cell.

21. Established: assessment unit maturity, the exploration 

maturity of the assessment unit. Assessment unit maturity 

is classified as “established” if more than 24 cells exceed 

the minimum total recovery.

22. Frontier: assessment unit maturity, the exploration maturity of the assessment unit. Assessment unit maturity is 

classified as “frontier” if 1 to 24 cells exceed the minimum total recovery.

23. Hypothetical: assessment-unit maturity, the exploration 

maturity of the assessment unit. Assessment-unit maturity 

is classified as “hypothetical” if no cells exceed the minimum total recovery.

24. Exploration Maturity: assessment-unit maturity from 

columns 21 to 23.

25. Median of First Third: median total recovery per cell of 

the set of tested cells equal to or greater than the minimum total recovery that constitute the first third of the 

total number of cells ranked according to date of discovery within the assessment unit, in million barrels of oil 

(MMBO) for oil assessment units or billion cubic feet of 

gas (BCFG) for gas assessment units.

The Main Input file contains input data from the 

FORSPAN Assessment Model for Continuous Accumulations: 

Basic Input Data Form used in this assessment. There are 

records for 186 Assessment Units (AUs), 139 of which were 

quantitatively assessed. In the Microsoft Excel version of this 

file, AUs that were not quantitatively assessed are colored purple; green cells mark major changes from previously published 

versions, as noted in the main text of this report. Blank cells 

represent no data. The Main Input file is designed to incorporate data from several versions of the input form. Many of the 

triangular distributions were originally described using a median 

as input. This later changed to a mode as input. For comparison 

across these differences, calculated values of the median, mode, 

and mean are given for many of the distributions. These calculated values would be either the variable value as entered on the 

input form (if given in that version) or a value calculated using 

the other parameters. This table contains 147 columns. Data 

columns are as follows:

1. AU Number: assessment unit code number.

2. AU: assessment unit name.

3. Version: version of assessment input form.

4. Reservoir Type: shale gas, coalbed gas, tight gas, or continuous oil.

5. Assessment Geologist: assessing geologist’s name.

6. Date: date of assessment.

7. Region Number: region code number.

8. Region: region name.

9. Province Number: province code number.

10. Province: province name.

11. TPS Number: total petroleum system (TPS) code number.

12. TPS: total petroleum system name.

13. Based on Data 1: data sources used to aid in completing 

the data-input form.

14. Based on Data 2: data sources used to aid in completing 

the data-input form.

15. Notes from Assessor 1: additional explanatory notes. Two 

references cited in this column are:

Jorjorian, Thomas, Liro, L.M., and Katz, B.J., 1989, 

Geochemical and well-log investigation of an actively 

generating source rock sequence—Waltman Shale, Wind 

River Basin, Wyoming [abs.]: American Association of 

Petroleum Geologists Bulletin, v. 73, no. 9, p. 1162.
32 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

26. Median of Second Third: median total recovery per cell of 

the set of tested cells equal to or greater than the minimum total recovery that constitute the second third of the 

total number of cells ranked according to date of discovery within the assessment unit, in million barrels of oil 

(MMBO) for oil assessment units or billion cubic feet of 

gas (BCFG) for gas assessment units.

27. Median of Third Third: median total recovery per cell of 

the set of tested cells equal to or greater than the minimum total recovery that constitute the third third of the 

total number of cells ranked according to date of discovery within the assessment unit, in million barrels of oil 

(MMBO) for oil assessment units or billion cubic feet of 

gas (BCFG) for gas assessment units.

28. Charge: charge probability, the probability for adequate 

petroleum charge for at least one untested cell equal to 

or larger than the minimum total recovery, somewhere in 

the assessment unit, having the potential to be added to 

reserves. Charge probability is given as a fractional value 

from 0 to 1.0.

29. Rocks: rocks probability, the probability for adequate reservoirs, traps, and seals for at least one untested cell equal 

to or larger than the minimum total recovery, somewhere 

in the assessment unit, having the potential to be added to 

reserves. Rocks probability is given as a fractional value 

from 0 to 1.0.

30. Timing: timing probability, the probability for favorable 

geologic timing for at least one untested cell equal to or 

larger than the minimum total recovery, somewhere in 

the assessment unit, having the potential to be added to 

reserves. Timing probability is given as a fractional value 

from 0 to 1.0.

31. AU Probability: geologic probability, the product of 

charge, rocks, and timing probabilities. Geologic probability is given as a fractional value from 0 to 1.0.

32. Access: accessibility probability, the probability for 

adequate location for necessary petroleum-related 

activities to discover at least one untested cell equal to 

or larger than the minimum total recovery, somewhere in 

the assessment unit, having the potential to be added to 

reserves. Accessibility probability is given as a fractional 

value from 0 to 1.0.

33. AU Area-minimum: the estimated minimum (F100) area 

of the assessment unit. The area is given in acres.

34. AU Area-median: the estimated median (F50) area of the 

assessment unit, as written on the input form. The area is 

given in acres.

35. AU Area-calculated median: the estimated median (F50) 

area of the assessment unit, as calculated from the parameters on the input form. The area is given in acres.

36. AU Area-mode: the estimated mode (most likely value) 

of the area of the assessment unit, as written on the input 

form. The area is given in acres.

37. AU Area-calculated mode: the estimated mode (most 

likely value) of the area of the assessment unit, as calculated from the parameters on the input form. The area is 

given in acres.

38. AU Area-maximum: the estimated maximum (F0) area of 

the assessment unit. The area is given in acres.

39. AU Area-mean: the estimated mean area of the assessment 

unit, as written on the input form. The area is given in acres.

40. AU Area-calculated mean: the estimated mean area of the 

assessment unit, as calculated from the parameters on the 

input form. The area is given in acres.

41. Cell Area-minimum: minimum area per cell of untested 

cells with potential, the estimated minimum (F100) area 

per cell of untested cells having the potential for additions 

to reserves in the assessment unit. This area is equivalent 

to the drainage area of wells. This area is given in acres.

42. Cell Area-median: the estimated median (F50) area per 

cell of untested cells having the potential for additions to 

reserves in the assessment unit, as written on the input 

form. This area is equivalent to the drainage area of wells. 

This area is given in acres.

43. Cell Area-calculated median: the estimated median (F50) 

area per cell of untested cells having the potential for additions to reserves in the assessment unit, as calculated from 

the parameters on the input form. This area is equivalent to 

the drainage area of wells. This area is given in acres.

44. Cell Area-mode: the estimated mode (most likely value) 

of the area per cell of untested cells with potential for 

additions to reserves in the assessment unit, as written on 

the input form. This area is equivalent to the drainage area 

of wells. This area is given in acres.

45. Cell Area-calculated mode: the estimated mode (most 

likely value) of the area per cell of untested cells with 

potential for additions to reserves in the assessment unit, 

as calculated from the parameters on the input form. This 

area is equivalent to the drainage area of wells. This area 

is given in acres.

46. Cell Area-maximum: maximum area per cell of untested 

cells with potential; the estimated maximum (F0) area per 

cell of untested cells having the potential for additions to 

reserves in the assessment unit. This area is equivalent to 

the drainage area of wells. This area is given in acres.

47. Cell Area-mean: the estimated mean area per cell of 

untested cells having the potential for additions to 

reserves in the assessment unit, as written on the input 

form. This area is equivalent to the drainage area of wells. 

This area is given in acres.
Appendix 2 33

48. Cell Area-calculated mean: the estimated mean area per 

cell of untested cells having the potential for additions 

to reserves in the assessment unit, as calculated from the 

parameters on the input form. This area is equivalent to 

the drainage area of wells. This area is given in acres.

49. Cell Area-minimum of mean: the estimated minimum 

value of the distribution of uncertainty of the mean area 

per cell of untested cells having the potential for additions 

to reserves in the assessment unit. This area is equivalent 

to the drainage area of wells. This area is given in acres.

50. Cell Area-maximum of mean: the estimated maximum 

value of the distribution of uncertainty of the mean area 

per cell of untested cells having the potential for additions 

to reserves in the assessment unit. This area is equivalent 

to the drainage area of wells. This area is given in acres.

51. Untested %-minimum: estimated minimum (F100) percentage of the total assessment-unit area that is untested.

52. Untested %-median: estimated median (F50) percentage 

of the total assessment-unit area that is untested, as written on the input form.

53. Untested %-calculated median: estimated median (F50) 

percentage of the total assessment-unit area that is 

untested, as calculated from the parameters on the input 

form.

54. Untested %-mode: estimated mode (most likely value) 

of the percentage of the total assessment-unit area that is 

untested, as written on the input form.

55. Untested %-calculated mode: estimated mode (most likely 

value) of the percentage of the total assessment-unit area 

that is untested, as calculated from the parameters on the 

input form.

56. Untested %-maximum: estimated maximum (F0) percentage of the total assessment-unit area that is untested.

57. Untested %-mean: estimated mean percentage of the total 

assessment-unit area that is untested, as written on the 

input form.

58. Untested %-calculated mean: estimated mean percentage 

of the total assessment-unit area that is untested, as calculated from the parameters on the input form.

59. Sweet Spot %-minimum: estimated minimum (F100) percentage of the untested area in the assessment unit having 

the potential for additions to reserves.

60. Sweet Spot %-median: estimated median (F50) percentage of the untested area in the assessment unit having the 

potential for additions to reserves, as written on the input 

form.

61. Sweet Spot %-calculated median: estimated median (F50) 

percentage of the untested area in the assessment unit having the potential for additions to reserves, as calculated 

from the parameters on the input form.

62. Sweet Spot %-mode: estimated mode (most likely value) 

of the percentage of the untested area in the assessment 

unit having the potential for additions to reserves, as written on the input form.

63. Sweet Spot %-calculated mode: estimated mode (most 

likely value) of the percentage of the untested area in 

the assessment unit having the potential for additions to 

reserves, as calculated from the parameters on the input 

form.

64. Sweet Spot %-maximum: estimated maximum (F0) percentage of the untested area in the assessment unit having 

the potential for additions to reserves.

65. Sweet Spot %-mean: estimated mean percentage of the 

untested area in the assessment unit having the potential 

for additions to reserves, as written on the input form.

66. Sweet Spot %-calculated mean: estimated mean percentage of the untested area in the assessment unit having the 

potential for additions to reserves, as calculated from the 

parameters on the input form.

67. Geologic Evidence: geologic rationale for distribution 

estimated for sweet spot percent.

68. Total Recovery per Cell-minimum: estimated minimum 

(F100) total recovery per cell for untested cells in the 

assessment unit having the potential for additions to 

reserves. This volume is given as million barrels of oil 

(MMBO) for oil assessment units and billion cubic feet of 

gas (BCFG) for gas assessment units.

69. Total Recovery per Cell-median: estimated median (F50) 

total recovery per cell for untested cells in the assessment 

unit having the potential for additions to reserves. This 

volume is given as million barrels of oil (MMBO) for oil 

assessment units and billion cubic feet of gas (BCFG) for 

gas assessment units.

70. Total Recovery per Cell-maximum: estimated maximum 

(F0) total recovery per cell for untested cells in the assessment unit having the potential for additions to reserves. 

This volume is given as million barrels of oil (MMBO) 

for oil assessment units and billion cubic feet of gas 

(BCFG) for gas assessment units.

71. Total Recovery per Cell-mean: estimated mean total 

recovery per cell for untested cells in the assessment unit 

having the potential for additions to reserves. This volume 

is given as million barrels of oil (MMBO) for oil assessment units and billion cubic feet of gas (BCFG) for gas 

assessment units.
34 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

72. GOR-minimum: estimated minimum (F100) gas to 

oil ratio (GOR), in cubic feet of gas per barrel of oil 

(CFG/BO), of untested cells equal to or larger than the 

minimum total recovery in oil assessment units.

73. GOR-median: estimated median (F50) gas to oil ratio 

(GOR), in cubic feet of gas per barrel of oil (CFG/BO), 

of untested cells equal to or larger than the minimum total 

recovery in oil assessment units, as written on the input form.

74. GOR-calculated median: estimated median (F50) gas 

to oil ratio (GOR), in cubic feet of gas per barrel of oil 

(CFG/BO), of untested cells equal to or larger than the 

minimum total recovery in oil assessment units, as calculated from the parameters on the input form.

75. GOR-mode: estimated mode (most likely value) of the 

gas to oil ratio (GOR), in cubic feet of gas per barrel of 

oil (CFG/BO), of untested cells equal to or larger than the 

minimum total recovery in oil assessment units, as written 

on the input form.

76. GOR-calculated mode: estimated mode (most likely 

value) of the gas to oil ratio (GOR), in cubic feet of gas 

per barrel of oil (CFG/BO), of untested cells equal to or 

larger than the minimum total recovery in oil assessment 

units, as calculated from the parameters on the input form.

77. GOR-maximum: estimated maximum (F0) gas to oil ratio 

(GOR), in cubic feet of gas per barrel of oil (CFG/BO), 

of untested cells equal to or larger than the minimum total 

recovery in oil assessment units.

78. NGLGR-minimum: estimated minimum (F100) natural 

gas liquids (NGL) to gas ratio (NGLGR), in barrels of 

natural gas liquids per million cubic feet of gas (BNGL/

MMCFG), of untested cells equal to or larger than the 

minimum total recovery in oil assessment units.

79. NGLGR-median: estimated median (F50) natural 

gas liquids (NGL) to gas ratio (NGLGR), in barrels 

of natural gas liquids per million cubic feet of gas 

(BNGL/MMCFG), of untested cells equal to or larger 

than the minimum total recovery in oil assessment units, 

as written on the input form.

80. NGLGR-calculated median: estimated median (F50) 

natural gas liquids (NGL) to gas ratio (NGLGR), in barrels of natural gas liquids per million cubic feet of gas 

(BNGL/MMCFG), of untested cells equal to or larger 

than the minimum total recovery in oil assessment units, 

as calculated from the parameters on the input form.

81. NGLGR-mode: estimated mode (most likely value) of 

the natural gas liquids (NGL) to gas ratio (NGLGR), in 

barrels of natural gas liquids per million cubic feet of gas 

(BNGL/MMCFG), of untested cells equal to or larger 

than the minimum total recovery in oil assessment units, 

as written on the input form.

82. NGLGR-calculated mode: estimated mode (most likely 

value) of the natural gas liquids (NGL) to gas ratio 

(NGLGR), in barrels of natural gas liquids per million 

cubic feet of gas (BNGL/MMCFG), of untested cells 

equal to or larger than the minimum total recovery in oil 

assessment units, as calculated from the parameters on the 

input form.

83. NGLGR-maximum: estimated maximum (F0) natural 

gas liquids (NGL) to gas ratio (NGLGR), in barrels 

of natural gas liquids per million cubic feet of gas 

(BNGL/MMCFG), of untested cells equal to or larger 

than the minimum total recovery in oil assessment units.

84. LGR-minimum: estimated minimum (F100) liquids (oil 

plus natural gas liquids) to gas ratio (LGR), in barrels of 

liquids per million cubic feet of gas (BNGL/MMCFG), of 

untested cells equal to or larger than the minimum total 

recovery in gas assessment units.

85. LGR-median: estimated median (F50) liquids (oil plus 

natural gas liquids) to gas ratio (LGR), in barrels of liquids 

per million cubic feet of gas (BNGL/MMCFG), of untested 

cells equal to or larger than the minimum total recovery in 

gas assessment units, as written on the input form.

86. LGR-calculated median: estimated median (F50) liquids 

(oil plus natural gas liquids) to gas ratio (LGR), in barrels 

of liquids per million cubic feet of gas (BNGL/MMCFG), 

of untested cells equal to or larger than the minimum total 

recovery in gas assessment units, as calculated from the 

parameters on the input form.

87. LGR-mode: estimated mode (most likely value) of 

the liquids (oil plus natural gas liquids) to gas ratio 

(LGR), in barrels of liquids per million cubic feet of gas 

(BNGL/MMCFG), of untested cells equal to or larger 

than the minimum total recovery in gas assessment units, 

as written on the input form.

88. LGR-calculated mode: estimated mode (most likely 

value) of the liquids (oil plus natural gas liquids) to gas 

ratio (LGR), in barrels of liquids per million cubic feet of 

gas (BNGL/MMCFG), of untested cells equal to or larger 

than the minimum total recovery in gas assessment units, 

as calculated from the parameters on the input form.

89. LGR-maximum: estimated maximum (F0) liquids (oil 

plus natural gas liquids) to gas ratio (LGR), in barrels of 

liquids per million cubic feet of gas (BNGL/MMCFG), of 

untested cells equal to or larger than the minimum total 

recovery in gas assessment units.

90. API-minimum: estimated minimum (F100) API (American 

Petroleum Institute) gravity, in degrees, of oil in untested 

cells in oil assessment units.

91. API-median: estimated median (F50) API (American 

Petroleum Institute) gravity, in degrees, of oil in untested 

cells in oil assessment units.
Appendix 2 35

92. API-mode: estimated mode (most likely value) of the 

API (American Petroleum Institute) gravity, in degrees, 

of oil in untested cells in oil assessment units.

93. API-maximum: estimated maximum (F0) API (American 

Petroleum Institute) gravity, in degrees, of oil in untested 

cells in oil assessment units.

94. Sulfur %-minimum: estimated minimum (F100) sulfur 

content, in percent, of oil in untested cells in oil assessment units.

95. Sulfur %-median: estimated median (F50) sulfur content, 

in percent, of oil in untested cells in oil assessment units.

96. Sulfur %-mode: estimated mode (most likely value) of 

the sulfur content, in percent, of oil in untested cells in 

oil assessment units.

97. Sulfur %-maximum: estimated maximum (F0) sulfur 

content, in percent, of oil in untested cells in oil assessment units.

98. (Oil) Water Depth-minimum: estimated minimum (F100) 

water depth, in meters, of oil in untested cells in oil 

assessment units (ocean, bays, or lakes; if applicable).

99. (Oil) Water Depth-median: estimated median (F50) water 

depth, in meters, of oil in untested cells in oil assessment 

units (ocean, bays, or lakes; if applicable).

100. (Oil) Water Depth-mode: estimated mode (most likely 

value) of the water depth, in meters, of oil in untested 

cells in oil assessment units (ocean, bays, or lakes; if 

applicable).

101. (Oil) Water Depth-maximum: estimated maximum (F0) 

water depth, in meters, of oil in untested cells in oil 

assessment units (ocean, bays, or lakes; if applicable).

102. (Oil) Drilling Depth-minimum: estimated minimum 

(F100) drilling depth, in meters, of oil in untested cells 

in oil assessment units.

103. (Oil) Drilling Depth-F75: estimated F75 drilling depth, 

in meters, of oil in untested cells in oil assessment units. 

An estimated 75 percent of the wells will be deeper than 

this value.

104. (Oil) Drilling Depth-median: estimated median (F50) 

drilling depth, in meters, of oil in untested cells in oil 

assessment units.

105. (Oil) Drilling Depth-mode: estimated mode (most likely 

value) of the drilling depth, in meters, of oil in untested 

cells in oil assessment units.

106. (Oil) Drilling Depth-F25: estimated F25 drilling depth, 

in meters, of oil in untested cells in oil assessment units. 

An estimated 25 percent of the wells will be deeper than 

this value.

107. (Oil) Drilling Depth-maximum: estimated maximum 

(F0) drilling depth, in meters, of oil in untested cells in 

oil assessment units.

108. Inert Gas %-minimum: estimated minimum (F100) inert 

gas content, in percent, of gas in untested cells in gas 

assessment units (nitrogen and helium, and so forth).

109. Inert Gas %-median: estimated median (F50) inert gas 

content, in percent, of gas in untested cells in gas assessment units (nitrogen and helium, and so forth).

110. Inert Gas %-mode: estimated mode (most likely value) 

of the inert gas content, in percent, of gas in untested 

cells in gas assessment units (nitrogen and helium, and 

so forth).

111. Inert Gas %-maximum: estimated maximum (F0) inert 

gas content, in percent, of gas in untested cells in gas 

assessment units (nitrogen and helium, and so forth).

112. CO2 %-minimum: estimated minimum (F100) carbon 

dioxide content, in percent, of gas in untested cells in gas 

assessment units.

113. CO2 %-median: estimated median (F50) carbon dioxide 

content, in percent, of gas in untested cells in gas assessment units.

114. CO2 %-mode: estimated mode (most likely value) of 

the carbon dioxide content, in percent, of gas in untested 

cells in gas assessment units.

115. CO2 %-maximum: estimated maximum (F0) carbon 

dioxide content, in percent, of gas in untested cells in gas 

assessment units.

116. H2S %-minimum: estimated minimum (F100) hydrogen 

sulfide content, in percent, of gas in untested cells in gas 

assessment units.

117. H2S %-median: estimated median (F50) hydrogen 

sulfide content, in percent, of gas in untested cells in gas 

assessment units.

118. H2S %-mode: estimated mode (most likely value) of the 

hydrogen sulfide content, in percent, of gas in untested 

cells in gas assessment units.

119. H2S %-maximum: estimated maximum (F0) hydrogen 

sulfide content, in percent, of gas in untested cells in gas 

assessment units.

120. BTU-minimum: estimated minimum (F100) heating 

value of gas, in BTU, of gas in untested cells in gas 

assessment units.

121. BTU-median: estimated median (F50) heating value of 

gas, in BTU, of gas in untested cells in gas assessment 

units.
36 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

122. BTU-mode: estimated mode (most likely value) of the 

heating value of gas, in BTU, of gas in untested cells in 

gas assessment units.

123. BTU-maximum: estimated maximum (F0) heating value 

of gas, in BTU, of gas in untested cells in gas assessment 

units.

124. (Gas) Water Depth-minimum: estimated minimum 

(F100) water depth, in meters, of gas in untested cells in 

gas assessment units (ocean, bays, or lakes; if applicable)

125. (Gas) Water Depth-median: estimated median (F50) 

water depth, in meters, of gas in untested cells in gas 

assessment units (ocean, bays, or lakes; if applicable).

126. (Gas) Water Depth-mode: estimated mode (most likely 

value) of the water depth, in meters, of gas in untested 

cells in gas assessment units (ocean, bays, or lakes; if 

applicable).

127. (Gas) Water Depth-maximum: estimated maximum (F0) 

water depth, in meters, of gas in untested cells in gas 

assessment units (ocean, bays, or lakes; if applicable).

128. (Gas) Drilling Depth-minimum: estimated minimum 

(F100) drilling depth, in meters, of gas in untested cells 

in gas assessment units.

129. (Gas) Drilling Depth-F75: estimated F75 drilling depth, 

in meters, of gas in untested cells in gas assessment 

units. An estimated 75 percent of the wells will be deeper 

than this value.

130. (Gas) Drilling Depth-median: estimated median (F50) 

drilling depth, in meters, of gas in untested cells in gas 

assessment units.

131. (Gas) Drilling Depth-mode: estimated mode (most likely 

value) of the drilling depth, in meters, of gas in untested 

cells in gas assessment units.

132. (Gas) Drilling Depth-F25: estimated F25 drilling depth, 

in meters, of gas in untested cells in gas assessment 

units. An estimated 25 percent of the wells will be deeper 

than this value.

133. (Gas) Drilling Depth-maximum: estimated maximum 

(F0) drilling depth, in meters, of gas in untested cells in 

gas assessment units.

134. Future Success Ratio-minimum: estimated minimum 

(F100) future success ratio, as percent.

135. Future Success Ratio-median: estimated median (F50) 

future success ratio, as percent, as written on the input form.

136. Future Success Ratio-calculated median: estimated 

median (F50) future success ratio, as percent, as calculated from the parameters on the input form.

137. Future Success Ratio-mode: estimated mode (most likely 

value) of the future success ratio, as percent, as written 

on the input form.

138. Future Success Ratio-calculated mode: estimated mode 

(most likely value) of the future success ratio, as percent, 

as calculated from the parameters on the input form.

139. Future Success Ratio-maximum: estimated maximum 

(F100) future success ratio, as percent.

140. Future Success Ratio-mean: estimated mean future success ratio, as percent, as written on the input form.

141. Future Success Ratio-calculated mean: estimated mean 

future success ratio, as percent, as calculated from the 

parameters on the input form.

142. Historic Success Ratio: historical success ratio, as percent.

143. Completion 1: typical well-completion practices (conventional, open hole, open cavity, other).

144. Completion 2: fraction of wells drilled that are typically 

stimulated.

145. Completion 3: predominant type of stimulation (none, 

frac, acid, other).

146. Completion 4: fraction of wells drilled that are horizontal.

147. Program Version: which version of the ACCESS 

program (version 1, 2, or 3) was used to perform the 

calculations.

The Ecosystem Allocations, Federal Land Allocations, 

Land Ownership Allocations, and State Allocations files contain 

volume-percent data of undiscovered petroleum allocated to 

ecosystem regions, Federal lands, general land-ownership 

parcels, and States. Cells are left blank if data are unavailable. 

Ecosystem allocation is based on the Bailey ecosystems 

(http://www.fs.fed.us/rm/ecoregions/products/map-ecoregionsunited-states/). The land ownership (including Federal ownership) information has come from several sources over the period 

in which these assessments were conducted. Currently the 

U.S. Geological Survey (USGS) Protected Areas Database of 

the United States (PADUS) is used (http://gis1.usgs.gov/arcgis/

rest/services/gap/PADUS_Owner/MapServer), but previously 

land-ownership data came primarily from Bureau of Land 

Management state offices.

The Ecosystem Allocations file contains 65 columns. 

There are records for 186 AUs, 139 of which were quantitatively assessed. In the Microsoft Excel version of this file, 

AUs that were not quantitatively assessed are colored purple; 

green cells mark major changes from previously published 

versions, as noted in the main text of this report. The sum of 

the percentages should equal those for the total area (excluding offshore) in the Land Ownership Allocations file. Data 

columns for these files are as follows:
Appendix 2 37

1. AU Number: assessment-unit code number.

2. AU: assessment-unit name.

3. Province Number: province code number.

4. Province: province name.

5. Area: area of the assessment unit in square kilometers.

6. Ecosystem 1 Name: name of first ecosystem that occupies 

all or part of the assessment-unit area.

7. Ecosystem 1 Area %: percentage of assessment-unit area 

that is occupied by ecosystem 1.

8. Ecosystem 1 Oil Volume %: estimated percentage of 

undiscovered oil volume allocated to ecosystem 1.

9. Ecosystem 1 Gas Volume %: estimated percentage of 

undiscovered gas volume allocated to ecosystem 1.

10. Ecosystem 2 Name: name of second ecosystem that occupies part of the assessment-unit area.

11. Ecosystem 2 Area %: percentage of assessment-unit area 

that is occupied by ecosystem 2.

12. Ecosystem 2 Oil Volume %: estimated percentage of 

undiscovered oil volume allocated to ecosystem 2.

13. Ecosystem 2 Gas Volume %: estimated percentage of 

undiscovered gas volume allocated to ecosystem 2.

14. Ecosystem 3 Name: name of third ecosystem that occupies part of the assessment-unit area.

15. Ecosystem 3 Area %: percentage of assessment-unit area 

that is occupied by ecosystem 3.

16. Ecosystem 3 Oil Volume %: estimated percentage of 

undiscovered oil volume allocated to ecosystem 3.

17. Ecosystem 3 Gas Volume %: estimated percentage of 

undiscovered gas volume allocated to ecosystem 3.

18. Ecosystem 4 Name: name of fourth ecosystem that occupies part of the assessment-unit area.

19. Ecosystem 4 Area %: percentage of assessment-unit area 

that is occupied by ecosystem 4.

20. Ecosystem 4 Oil Volume %: estimated percentage of 

undiscovered oil volume allocated to ecosystem 4.

21. Ecosystem 4 Gas Volume %: estimated percentage of 

undiscovered gas volume allocated to ecosystem 4.

22. Ecosystem 5 Name: name of fifth ecosystem that occupies 

part of the assessment-unit area.

23. Ecosystem 5 Area %: percentage of assessment-unit area 

that is occupied by ecosystem 5.

24. Ecosystem 5 Oil Volume %: estimated percentage of 

undiscovered oil volume allocated to ecosystem 5.

25. Ecosystem 5 Gas Volume %: estimated percentage of 

undiscovered gas volume allocated to ecosystem 5.

26. Ecosystem 6 Name: name of sixth ecosystem that occupies part of the assessment-unit area.

27. Ecosystem 6 Area %: percentage of assessment-unit area 

that is occupied by ecosystem 6.

28. Ecosystem 6 Oil Volume %: estimated percentage of 

undiscovered oil volume allocated to ecosystem 6.

29. Ecosystem 6 Gas Volume %: estimated percentage of 

undiscovered gas volume allocated to ecosystem 6.

30. Ecosystem 7 Name: name of seventh ecosystem that 

occupies part of the assessment-unit area.

31. Ecosystem 7 Area %: percentage of assessment-unit area 

that is occupied by ecosystem 7.

32. Ecosystem 7 Oil Volume %: estimated percentage of 

undiscovered oil volume allocated to ecosystem 7.

33. Ecosystem 7 Gas Volume %: estimated percentage of 

undiscovered gas volume allocated to ecosystem 7.

34. Ecosystem 8 Name: name of eighth ecosystem that occupies part of the assessment-unit area.

35. Ecosystem 8 Area %: percentage of assessment-unit area 

that is occupied by ecosystem 8.

36. Ecosystem 8 Oil Volume %: estimated percentage of 

undiscovered oil volume allocated to ecosystem 8.

37. Ecosystem 8 Gas Volume %: estimated percentage of 

undiscovered gas volume allocated to ecosystem 8.

38. Ecosystem 9 Name: name of ninth ecosystem that occupies part of the assessment-unit area.

39. Ecosystem 9 Area %: percentage of assessment-unit area 

that is occupied by ecosystem 9.

40. Ecosystem 9 Oil Volume %: estimated percentage of 

undiscovered oil volume allocated to ecosystem 9.

41. Ecosystem 9 Gas Volume %: estimated percentage of 

undiscovered gas volume allocated to ecosystem 9.

42. Ecosystem 10 Name: name of tenth ecosystem that occupies part of the assessment-unit area.

43. Ecosystem 10 Area %: percentage of assessment-unit area 

that is occupied by ecosystem 10.

44. Ecosystem 10 Oil Volume %: estimated percentage of 

undiscovered oil volume allocated to ecosystem 10.
38 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

45. Ecosystem 10 Gas Volume %: estimated percentage of 

undiscovered gas volume allocated to ecosystem 10.

46. Ecosystem 11 Name: name of eleventh ecosystem that 

occupies part of the assessment-unit area.

47. Ecosystem 11 Area %: percentage of assessment-unit area 

that is occupied by ecosystem 11.

48. Ecosystem 11 Oil Volume %: estimated percentage of 

undiscovered oil volume allocated to ecosystem 11.

49. Ecosystem 11 Gas Volume %: estimated percentage of 

undiscovered gas volume allocated to ecosystem 11.

50. Ecosystem 12 Name: name of twelfth ecosystem that 

occupies part of the assessment-unit area.

51. Ecosystem 12 Area %: percentage of assessment-unit area 

that is occupied by ecosystem 12.

52. Ecosystem 12 Oil Volume %: estimated percentage of 

undiscovered oil volume allocated to ecosystem 12.

53. Ecosystem 12 Gas Volume %: estimated percentage of 

undiscovered gas volume allocated to ecosystem 12.

54. Ecosystem 13 Name: name of thirteenth ecosystem that 

occupies part of the assessment-unit area.

55. Ecosystem 13 Area %: percentage of assessment-unit area 

that is occupied by ecosystem 13.

56. Ecosystem 13 Oil Volume %: estimated percentage of 

undiscovered oil volume allocated to ecosystem 13.

57. Ecosystem 13 Gas Volume %: estimated percentage of 

undiscovered gas volume allocated to ecosystem 13.

58. Ecosystem 14 Name: name of fourteenth ecosystem that 

occupies part of the assessment-unit area.

59. Ecosystem 14 Area %: percentage of assessment-unit area 

that is occupied by ecosystem 14.

60. Ecosystem 14 Oil Volume %: estimated percentage of 

undiscovered oil volume allocated to ecosystem 14.

61. Ecosystem 14 Gas Volume %: estimated percentage of 

undiscovered gas volume allocated to ecosystem 14.

62. Ecosystem 15 Name: name of fifteenth ecosystem that 

occupies part of the assessment-unit area.

63. Ecosystem 15 Area %: percentage of assessment-unit area 

that is occupied by ecosystem 15.

64. Ecosystem 15 Oil Volume %: estimated percentage of 

undiscovered oil volume allocated to ecosystem 15.

65. Ecosystem 15 Gas Volume %: estimated percentage of 

undiscovered gas volume allocated to ecosystem 15.

The Federal Land Allocations file contains 85 columns. 

There are records for 186 AUs, 139 of which were quantitatively assessed. In the Microsoft Excel version of this file, AUs 

that were not quantitatively assessed are colored purple; green 

cells mark major changes from previously published versions, as noted in the main text of this report. The sum of the 

percentages should equal those for Federal lands in the Land 

Ownership Allocations file. Data columns for these files are:

1. AU Number: assessment-unit code number.

2. AU: assessment-unit name.

3. Province Number: province code number.

4. Province: province name.

5. Area: area of the assessment unit in square kilometers.

6. BLM: “Bureau of Land Management (BLM),” name of 

Federal land that occupies all or part of the assessmentunit area.

7. BLM Area %: percentage of assessment-unit area that is 

occupied by Bureau of Land Management lands.

8. BLM Oil Volume %: estimated percentage of undiscovered oil volume allocated to Bureau of Land Management 

lands.

9. BLM Gas Volume %: estimated percentage of undiscovered gas volume allocated to Bureau of Land Management lands.

10. BLMW: “BLM Wilderness Areas (BLMW),” name of 

Federal land that occupies all or part of the assessmentunit area.

11. BLMW Area %: percentage of assessment-unit area that 

is occupied by Bureau of Land Management Wilderness 

Areas.

12. BLMW Oil Volume %: estimated percentage of undiscovered oil volume allocated to Bureau of Land Management 

Wilderness Areas.

13. BLMW Gas Volume %: estimated percentage of undiscovered gas volume allocated to Bureau of Land Management Wilderness Areas.

14. BLMR: “BLM Roadless Areas (BLMR),” name of Federal land that occupies all or part of the assessment-unit 

area.

15. BLMR Area %: percentage of assessment-unit area that 

is occupied by Bureau of Land Management Roadless 

Areas.

16. BLMR Oil Volume %: estimated percentage of undiscovered oil volume allocated to Bureau of Land Management 

Roadless Areas.
Appendix 2 39

17. BLMR Gas Volume %: estimated percentage of undiscovered gas volume allocated to Bureau of Land Management Roadless Areas.

18. NPS: “National Park Service (NPS),” name of Federal 

land that occupies all or part of the assessment-unit area.

19. NPS Area %: percentage of assessment-unit area that is 

occupied by National Park Service lands.

20. NPS Oil Volume %: estimated percentage of undiscovered 

oil volume allocated to National Park Service lands.

21. NPS Gas Volume %: estimated percentage of undiscovered gas volume allocated to National Park Service lands.

22. NPSW: “NPS Wilderness Areas (NPSW),” name of Federal land that occupies all or part of the assessment-unit 

area.

23. NPSW Area %: percentage of assessment-unit area that is 

occupied by National Park Service Wilderness Areas.

24. NPSW Oil Volume %: estimated percentage of undiscovered oil volume allocated to National Park Service 

Wilderness Areas.

25. NPSW Gas Volume %: estimated percentage of undiscovered gas volume allocated to National Park Service 

Wilderness Areas.

26. NPSP: “NPS Withdrawals (NPSP),” name of Federal land 

that occupies all or part of the assessment-unit area.

27. NPSP Area %: percentage of assessment-unit area that is 

occupied by National Park Service Withdrawals.

28. NPSP Oil Volume %: estimated percentage of undiscovered oil volume allocated to National Park Service 

Withdrawals.

29. NPSP Gas Volume %: estimated percentage of undiscovered gas volume allocated to National Park Service 

Withdrawals.

30. FS: “Forest Service (FS),” name of Federal land that 

occupies all or part of the assessment-unit area.

31. FS Area %: percentage of assessment-unit area that is 

occupied by USDA Forest Service lands.

32. FS Oil Volume %: estimated percentage of undiscovered 

oil volume allocated to USDA Forest Service lands.

33. FS Gas Volume %: estimated percentage of undiscovered 

gas volume allocated to USDA Forest Service lands.

34. FSW: “FS Wilderness Areas (FSW),” name of Federal 

land that occupies all or part of the assessment-unit area.

35. FSW Area %: percentage of assessment-unit area that is 

occupied by USDA Forest Service Wilderness Areas.

36. FSW Oil Volume %: estimated percentage of undiscovered oil volume allocated to USDA Forest Service Wilderness Areas.

37. FSW Gas Volume %: estimated percentage of undiscovered gas volume allocated to USDA Forest Service 

Wilderness Areas.

38. FSR: “FS Roadless Areas (FSR),” name of Federal land 

that occupies all or part of the assessment-unit area.

39. FSR Area %: percentage of assessment-unit area that is 

occupied by USDA Forest Service Roadless Areas.

40. FSR Oil Volume %: estimated percentage of undiscovered 

oil volume allocated to USDA Forest Service Roadless 

Areas.

41. FSR Gas Volume %: estimated percentage of undiscovered gas volume allocated to USDA Forest Service Roadless Areas.

42. FSP: “FS Protected Withdrawals (FSP),” name of Federal 

land that occupies all or part of the assessment-unit area.

43. FSP Area %: percentage of assessment-unit area that is 

occupied by USDA Forest Service Protected Withdrawals.

44. FSP Oil Volume %: estimated percentage of undiscovered 

oil volume allocated to USDA Forest Service Protected 

Withdrawals.

45. FSP Gas Volume %: estimated percentage of undiscovered gas volume allocated to USDA Forest Service 

Protected Withdrawals.

46. FWS: “U.S. Fish and Wildlife Service (USFWS),” name 

of Federal land that occupies all or part of the assessmentunit area.

47. FWS Area %: percentage of assessment-unit area that is 

occupied by U.S. Fish and Wildlife Service lands.

48. FWS Oil Volume %: estimated percentage of undiscovered oil volume allocated to U.S. Fish and Wildlife 

Service lands.

49. FWS Gas Volume %: estimated percentage of undiscovered gas volume allocated to U.S. Fish and Wildlife 

Service lands.

50. FWSW: “USFWS Wilderness Areas (USFWSW),” name 

of Federal land that occupies all or part of the assessmentunit area.

51. FWSW Area %: percentage of assessment-unit area that 

is occupied by U.S. Fish and Wildlife Service Wilderness 

Areas.
40 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

52. FWSW Oil Volume %: estimated percentage of undiscovered oil volume allocated to U.S. Fish and Wildlife 

Service Wilderness Areas.

53. FWSW Gas Volume %: estimated percentage of undiscovered gas volume allocated to U.S. Fish and Wildlife 

Service Wilderness Areas.

54. FWSP: “USFWS Protected Withdrawals (USFWSP),” 

name of Federal land that occupies all or part of the 

assessment-unit area.

55. FWSP Area %: percentage of assessment-unit area that 

is occupied by U.S. Fish and Wildlife Service Protected 

Withdrawals.

56. FWSP Oil Volume %: estimated percentage of undiscovered oil volume allocated to U.S. Fish and Wildlife 

Service Protected Withdrawals.

57. FWSP Gas Volume %: estimated percentage of undiscovered gas volume allocated to U.S. Fish and Wildlife 

Service Protected Withdrawals.

58. WS: “Wilderness Study Areas (WS),” name of Federal 

land that occupies all or part of the assessment-unit area.

59. WS Area %: percentage of assessment-unit area that is 

occupied by Wilderness Study Areas.

60. WS Oil Volume %: estimated percentage of undiscovered 

oil volume allocated to Wilderness Study Areas.

61. WS Gas Volume %: estimated percentage of undiscovered 

gas volume allocated to Wilderness Study Areas.

62. DOE: “Department of Energy (DOE),” name of Federal 

land that occupies all or part of the assessment-unit area.

63. DOE Area %: percentage of assessment-unit area that is 

occupied by Department of Energy lands.

64. DOE Oil Volume %: estimated percentage of undiscovered oil volume allocated to Department of Energy lands.

65. DOE Gas Volume %: estimated percentage of undiscovered gas volume allocated to Department of Energy lands.

66. DOD: “Department of Defense (DOD),” name of Federal 

land that occupies all or part of the assessment-unit area.

67. DOD Area %: percentage of assessment-unit area that is 

occupied by Department of Defense lands.

68. DOD Oil Volume %: estimated percentage of undiscovered oil volume allocated to Department of Defense lands.

69. DOD Gas Volume %: estimated percentage of undiscovered gas volume allocated to Department of Defense 

lands.

70. BOR: “Bureau of Reclamation (BOR),” name of Federal 

land that occupies all or part of the assessment-unit area.

71. BOR Area %: percentage of assessment-unit area that is 

occupied by Bureau of Reclamation lands.

72. BOR Oil Volume %: estimated percentage of undiscovered oil volume allocated to Bureau of Reclamation lands.

73. BOR Gas Volume %: estimated percentage of undiscovered gas volume allocated to Bureau of Reclamation 

lands.

74. TVA: “Tennessee Valley Authority (TVA),” name of Federal 

land that occupies all or part of the assessment-unit area.

75. TVA Area %: percentage of assessment-unit area that is 

occupied by Tennessee Valley Authority lands.

76. TVA Oil Volume %: estimated percentage of undiscovered 

oil volume allocated to Tennessee Valley Authority lands.

77. TVA Gas Volume %: estimated percentage of undiscovered gas volume allocated to Tennessee Valley Authority 

lands.

78. Other: “Other Federal,” other unspecified Federal lands 

that occupy all part of the assessment-unit area.

79. Other Area %: percentage of assessment-unit area that is 

occupied by other unspecified Federal lands.

80. Other Oil Volume %: estimated percentage of undiscovered oil volume allocated to other unspecified Federal 

lands.

81. Other Gas Volume %: estimated percentage of undiscovered gas volume allocated to other unspecified Federal 

lands.

82. Fed 20: name of additional specified Federal lands that 

occupy all or part of the assessment-unit area.

83. Fed 20 Area %: percentage of assessment-unit area that is 

occupied by additional specified Federal lands.

84. Fed 20 Oil Volume %: estimated percentage of undiscovered oil volume allocated to additional specified Federal 

lands.

85. Fed 20 Gas Volume %: estimated percentage of undiscovered gas volume allocated to additional specified Federal 

lands.

The Land Ownership Allocations file contains 57 

columns. There are records for 186 AUs, 139 of which were 

quantitatively assessed. In the Microsoft Excel version of this 

file, AUs that were not quantitatively assessed are colored 

purple; green cells mark major changes from previously published versions, as noted in the main text of this report. The 

sum of the percentages should equal 100. Data columns for 

these files are as follows:
Appendix 2 41

1. AU Number: assessment-unit code number.

2. AU: assessment-unit name.

3. Province Number: province code number.

4. Province: province name.

5. Area: area of the assessment unit in square kilometers.

6. Federal: “Federal Lands,” all Federal lands that occupy all 

or part of the assessment-unit area.

7. Federal Area %: percentage of assessment-unit area that is 

occupied by Federal lands.

8. Federal Oil Volume %: estimated percentage of undiscovered oil volume allocated to Federal lands.

9. Federal Gas Volume %: estimated percentage of undiscovered gas volume allocated to Federal lands.

10. Private: “Private Lands,” all private lands that occupy all 

or part of the assessment-unit area.

11. Private Area %: percentage of assessment-unit area that is 

occupied by private lands.

12. Private Oil Volume %: estimated percentage of undiscovered oil volume allocated to private lands.

13. Private Gas Volume %: estimated percentage of undiscovered gas volume allocated to private lands.

14. Tribal: “Tribal Lands,” all tribal lands that occupy all or 

part of the assessment-unit area.

15. Tribal Area %: percentage of assessment-unit area that is 

occupied by tribal lands.

16. Tribal Oil Volume %: estimated percentage of undiscovered oil volume allocated to tribal lands.

17. Tribal Gas Volume %: estimated percentage of undiscovered gas volume allocated to tribal lands.

18. Other: name of other unspecified lands or offshore areas 

that occupy all or part of the assessment-unit area.

19. Other Area %: percentage of assessment-unit area that is 

occupied by other unspecified lands or offshore areas.

20. Other Oil Volume %: estimated percentage of undiscovered oil volume allocated to other unspecified lands or 

offshore areas.

21. Other Gas Volume %: estimated percentage of undiscovered gas volume allocated to other unspecified lands or 

offshore areas.

22. State 1: name of first State category which State-owned 

lands or waters occupy all or part of the assessment-unit 

area.

23. State 1 Area %: percentage of assessment-unit area that is 

occupied by State 1-owned lands or waters.

24. State 1 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 1-owned lands or 

waters.

25. State 1 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 1-owned lands or 

waters.

26. State 2: name of second State category which Stateowned lands or waters occupy all or part of the assessment-unit area.

27. State 2 Area %: percentage of assessment-unit area that is 

occupied by State 2-owned lands or waters.

28. State 2 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 2-owned lands or 

waters.

29. State 2 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 2-owned lands or 

waters.

30. State 3: name of third State category which State-owned 

lands or waters occupy all or part of the assessment-unit 

area.

31. State 3 Area %: percentage of assessment-unit area that is 

occupied by State 3-owned lands or waters.

32. State 3 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 3-owned lands or 

waters.

33. State 3 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 3-owned lands or 

waters.

34. State 4: name of fourth State category which State-owned 

lands or waters occupy all or part of the assessment-unit 

area.

35. State 4 Area %: percentage of assessment-unit area that is 

occupied by State 4-owned lands or waters.

36. State 4 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 4-owned lands or 

waters.

37. State 4 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 4-owned lands or 

waters.

38. State 5: name of fifth State category which State-owned 

lands or waters occupy all or part of the assessment-unit 

area.
42 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

39. State 5 Area %: percentage of assessment-unit area that is 

occupied by State 5-owned lands or waters.

40. State 5 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 5-owned lands or 

waters.

41. State 5 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 5-owned lands or 

waters.

42. State 6: name of sixth State category which State-owned 

lands or waters occupy all or part of the assessment-unit 

area.

43. State 6 Area %: percentage of assessment-unit area that is 

occupied by State 6-owned lands or waters.

44. State 6 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 6-owned lands or 

waters.

45. State 6 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 6-owned lands or 

waters.

46. State 7: name of seventh State category which Stateowned lands or waters occupy all or part of the assessment-unit area.

47. State 7 Area %: percentage of assessment-unit area that is 

occupied by State 7-owned lands or waters.

48. State 7 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 7-owned lands or 

waters.

49. State 7 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 7-owned lands or 

waters.

50. State 8: name of eighth State category which State-owned 

lands or waters occupy all or part of the assessment-unit 

area.

51. State 8 Area %: percentage of assessment-unit area that is 

occupied by State 8-owned lands or waters.

52. State 8 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 8-owned lands or 

waters.

53. State 8 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 8-owned lands or 

waters.

54. State 9: name of ninth State category which State-owned 

lands or waters occupy all or part of the assessment-unit 

area.

55. State 9 Area %: percentage of assessment-unit area that is 

occupied by State 9-owned lands or waters.

56. State 9 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 9-owned lands or 

waters.

57. State 9 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 9-owned lands or 

waters.

The State Allocations file contains 53 columns. There 

are records for 186 AUs, 139 of which were quantitatively 

assessed. In the Microsoft Excel version of this file, AUs that 

were not quantitatively assessed are colored purple; green 

cells mark major changes from previously published versions, as noted in the main text of this report. The sum of the 

percentages should equal 100. Data columns for these files are 

as follows:

1. AU Number: assessment-unit code number.

2. AU: assessment-unit name.

3. Province Number: province code number.

4. Province: province name.

5. Area: area of the assessment unit in square kilometers.

6. State 1 Name: name of first State (onshore and offshore) 

that occupies all or part of the assessment-unit area.

7. State 1 Area %: percentage of assessment-unit area that is 

occupied by State 1.

8. State 1 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 1.

9. State 1 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 1.

10. State 2 Name: name of second State (onshore and offshore) that occupies part of the assessment-unit area.

11. State 2 Area %: percentage of assessment-unit area that is 

occupied by State 2.

12. State 2 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 2.

13. State 2 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 2.

14. State 3 Name: name of third State (onshore and offshore) 

that occupies part of the assessment-unit area.

15. State 3 Area %: percentage of assessment-unit area that is 

occupied by State 3.

16. State 3 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 3.

17. State 3 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 3.
Appendix 2 43

18. State 4 Name: name of fourth State (onshore and offshore) that occupies part of the assessment-unit area.

19. State 4 Area %: percentage of assessment-unit area that is 

occupied by State 4.

20. State 4 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 4.

21. State 4 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 4.

22. State 5 Name: name of fifth State (onshore and offshore) 

that occupies part of the assessment-unit area.

23. State 5 Area %: percentage of assessment-unit area that is 

occupied by State 5.

24. State 5 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 5.

25. State 5 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 5.

26. State 6 Name: name of sixth State (onshore and offshore) 

that occupies part of the assessment-unit area.

27. State 6 Area %: percentage of assessment-unit area that is 

occupied by State 6.

28. State 6 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 6.

29. State 6 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 6.

30. State 7 Name: name of seventh State (onshore and offshore) that occupies part of the assessment-unit area.

31. State 7 Area %: percentage of assessment-unit area that is 

occupied by State 7.

32. State 7 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 7.

33. State 7 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 7.

34. State 8 Name: name of eighth State (onshore and offshore) that occupies part of the assessment-unit area.

35. State 8 Area %: percentage of assessment-unit area that is 

occupied by State 8.

36. State 8 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 8.

37. State 8 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 8.

38. State 9 Name: name of ninth State (onshore and offshore) 

that occupies part of the assessment-unit area.

39. State 9 Area %: percentage of assessment-unit area that is 

occupied by State 9.

40. State 9 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 9.

41. State 9 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 9.

42. State 10 Name: name of tenth State (onshore and offshore) that occupies part of the assessment-unit area.

43. State 10 Area %: percentage of assessment-unit area that 

is occupied by State 10.

44. State 10 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 10.

45. State 10 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 10.

46. State 11 Name: name of eleventh State (onshore and offshore) that occupies part of the assessment-unit area.

47. State 11 Area %: percentage of assessment-unit area that 

is occupied by State 11.

48. State 11 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 11.

49. State 11 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 11.

50. State 12 Name: name of twelfth State (onshore and offshore) that occupies part of the assessment-unit area.

51. State 12 Area %: percentage of assessment-unit area that 

is occupied by State 12.

52. State 12 Oil Volume %: estimated percentage of undiscovered oil volume allocated to State 12.

53. State 12 Gas Volume %: estimated percentage of undiscovered gas volume allocated to State 12.

The Continuous Results file contains 49 columns. There 

are records for the 139 AUs that were quantitatively assessed. 

Data columns for these files are as follows:

1. AU Number: USGS assessment-unit code number.

2. AU: USGS assessment unit name

3. Province Number: province code number.

4. Province: province name.

5. AU Type: assessment unit type, the primary commodity 

type in the assessment unit, based on the gas-to-oil ratio 

(GOR) of the petroleum endowment, which includes both 

the discovered and undiscovered petroleum. An assessment unit is characterized as being oil prone if the gas-tooil ratio (GOR) is less than 20,000 cubic feet of gas per 

barrel of oil; otherwise, it is gas prone.
44 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

6. Date: date of assessment.

7. AU Probability: the probability that there exists the 

potential for at least one well equal to or larger than the 

minimum well size somewhere in the assessment unit. 

Assessment unit probability is given as a fractional value 

from 0 to 1.0.

8. Oil in Oil Deposit (MMBO), Mean: the estimated 

mean (average) value of undrilled oil in the assessment 

unit. The volume is given in millions of barrels of oil 

(MMBO).

9. Oil in Oil Deposit (MMBO), Std. Dev.: the estimated 

standard deviation of the distribution of undrilled oil in 

the assessment unit. The volume is given in millions of 

barrels of oil (MMBO).

10. Oil in Oil Deposit (MMBO), F95: the estimated value of 

undrilled oil such that there is a 95 percent probability 

that this amount or more exists in the assessment unit. The 

volume is given in millions of barrels of oil (MMBO).

11. Oil in Oil Deposit (MMBO), F75: the estimated value of 

undrilled oil such that there is a 75 percent probability 

that this amount or more exists in the assessment unit. The 

volume is given in millions of barrels of oil (MMBO).

12. Oil in Oil Deposit (MMBO), F50: the estimated value of 

undrilled oil such that there is a 50 percent probability 

that this amount or more exists in the assessment unit. 

This is the median value. The volume is given in millions 

of barrels of oil (MMBO).

13. Oil in Oil Deposit (MMBO), F25: the estimated value of 

undrilled oil such that there is a 25 percent probability 

that this amount or more exists in the assessment unit. The 

volume is given in millions of barrels of oil (MMBO).

14. Oil in Oil Deposit (MMBO), F5: the estimated value of 

undrilled oil such that there is a 5 percent probability that 

this amount or more exists in the assessment unit. The 

volume is given in millions of barrels of oil (MMBO).

15. Gas in Oil Deposit (BCFG), Mean: the estimated mean 

(average) value of undrilled associated/dissolved gas in 

the assessment unit. The volume is given in billions of 

cubic feet of gas (BCFG).

16. Gas in Oil Deposit (BCFG), Std. Dev.: the estimated standard deviation of the distribution of undrilled associated/

dissolved gas in the assessment unit. The volume is given 

in billions of cubic feet of gas (BCFG).

17. Gas in Oil Deposit (BCFG), F95: the estimated value of 

undrilled associated/dissolved gas such that there is a 95 

percent probability that this amount or more exists in the 

assessment unit. The volume is given in billions of cubic 

feet of gas (BCFG).

18. Gas in Oil Deposit (BCFG), F75: the estimated value of 

undrilled associated/dissolved gas such that there is a 75 

percent probability that this amount or more exists in the 

assessment unit. The volume is given in billions of cubic 

feet of gas (BCFG).

19. Gas in Oil Deposit (BCFG), F50: the estimated value of 

undrilled associated/dissolved gas such that there is a 50 

percent probability that this amount or more exists in the 

assessment unit. This is the median value. The volume is 

given in billions of cubic feet of gas (BCFG).

20. Gas in Oil Deposit (BCFG), F25: the estimated value of 

undrilled associated/dissolved gas such that there is a 25 

percent probability that this amount or more exists in the 

assessment unit. The volume is given in billions of cubic 

feet of gas (BCFG).

21. Gas in Oil Deposit (BCFG), F5: the estimated value of 

undrilled associated/dissolved gas such that there is a 5 

percent probability that this amount or more exists in the 

assessment unit. The volume is given in billions of cubic 

feet of gas (BCFG).

22. NGL in Oil Deposit (MMBNGL), Mean: the estimated 

mean (average) value of undrilled NGL in the assessment 

unit. The volume is given in millions of barrels of NGL 

(MMBNGL).

23. NGL in Oil Deposit (MMBNGL), Std. Dev.: the estimated 

standard deviation of the distribution of undrilled NGL in 

the assessment unit. The volume is given in millions of 

barrels of NGL (MMBNGL).

24. NGL in Oil Deposit (MMBNGL), F95: the estimated 

value of undrilled NGL such that there is a 95 percent 

probability that this amount or more exists in the assessment unit. The volume is given in millions of barrels of 

NGL (MMBNGL).

25. NGL in Oil Deposit (MMBNGL), F75: the estimated 

value of undrilled NGL such that there is a 75 percent 

probability that this amount or more exists in the assessment unit. The volume is given in millions of barrels of 

NGL (MMBNGL).

26. NGL in Oil Deposit (MMBNGL), F50: the estimated 

value of undrilled NGL such that there is a 50 percent 

probability that this amount or more exists in the assessment unit. This is the median value. The volume is given 

in millions of barrels of NGL (MMBNGL).

27. NGL in Oil Deposit (MMBNGL), F25: the estimated 

value of undrilled NGL such that there is a 25 percent 

probability that this amount or more exists in the assessment unit. The volume is given in millions of barrels of 

NGL (MMBNGL).
Appendix 2 45

28. NGL in Oil Deposit (MMBNGL), F5: the estimated value 

of undrilled NGL such that there is a 5 percent probability that this amount or more exists in the assessment 

unit. The volume is given in millions of barrels of NGL 

(MMBNGL).

29. Gas in Gas Deposit (BCFG), Mean: the estimated mean 

(average) value of undrilled nonassociated gas in the 

assessment unit. The volume is given in billions of cubic 

feet of gas (BCFG).

30. Gas in Gas Deposit (BCFG), Std. Dev.: the estimated 

standard deviation of the distribution of undrilled nonassociated gas in the assessment unit. The volume is given 

in billions of cubic feet of gas (BCFG).

31. Gas in Gas Deposit (BCFG), F95: the estimated value of 

undrilled nonassociated gas such that there is a 95 percent 

probability that this amount or more exists in the assessment unit. The volume is given in billions of cubic feet of 

gas (BCFG).

32. Gas in Gas Deposit (BCFG), F75: the estimated value of 

undrilled nonassociated gas such that there is a 75 percent 

probability that this amount or more exists in the assessment unit. The volume is given in billions of cubic feet of 

gas (BCFG).

33. Gas in Gas Deposit (BCFG), F50: the estimated value of 

undrilled nonassociated gas such that there is a 50 percent 

probability that this amount or more exists in the assessment unit. This is the median value. The volume is given 

in billions of cubic feet of gas (BCFG).

34. Gas in Gas Deposit (BCFG), F25: the estimated value of 

undrilled nonassociated gas such that there is a 25 percent 

probability that this amount or more exists in the assessment unit. The volume is given in billions of cubic feet of 

gas (BCFG).

35. Gas in Gas Deposit (BCFG), F5: the estimated value of 

undrilled nonassociated gas such that there is a 5 percent 

probability that this amount or more exists in the assessment unit. The volume is given in billions of cubic feet of 

gas (BCFG).

36. Liquids in Gas Deposit (MMBL), Mean: the estimated 

mean (average) value of undrilled liquids in the assessment unit. The volume is given in millions of barrels of 

liquids (MMBL).

37. Liquids in Gas Deposit (MMBL), Std. Dev.: the estimated 

standard deviation of the distribution of undrilled liquids 

in the assessment unit. The volume is given in millions of 

barrels of liquids (MMBL).

38. Liquids in Gas Deposit (MMBL), F95: the estimated 

value of undrilled liquids such that there is a 95 percent 

probability that this amount or more exists in the assessment unit. The volume is given in millions of barrels of 

liquids (MMBL).

39. Liquids in Gas Deposit (MMBL), F75: the estimated 

value of undrilled liquids such that there is a 75 percent 

probability that this amount or more exists in the assessment unit. The volume is given in millions of barrels of 

liquids (MMBL).

40. Liquids in Gas Deposit (MMBL), F50: the estimated 

value of undrilled liquids such that there is a 50 percent 

probability that this amount or more exists in the assessment unit. This is the median value. The volume is given 

in millions of barrels of liquids (MMBL).

41. Liquids in Gas Deposit (MMBL), F25: the estimated 

value of undrilled liquids such that there is a 25 percent 

probability that this amount or more exists in the assessment unit. The volume is given in millions of barrels of 

liquids (MMBL).

42. Liquids in Gas Deposit (MMBL), F5: the estimated value 

of undrilled liquids such that there is a 5 percent probability that this amount or more exists in the assessment 

unit. The volume is given in millions of barrels of liquids 

(MMBL).

43. Number of Cells, Mean: the estimated mean (average) 

value of number of untested cells with resource potential 

in the assessment unit.

44. Number of Cells, Std. Dev.: the estimated standard deviation of the distribution of number of untested cells with 

resource potential in the assessment unit.

45. Number of Cells, F95: the estimated value of number of 

untested cells with resource potential such that there is a 

95 percent probability that this amount or more exists in 

the assessment unit.

46. Number of Cells, F75: the estimated value of number of 

untested cells with resource potential such that there is a 

75 percent probability that this amount or more exists in 

the assessment unit.

47. Number of Cells, F50: the estimated value of number of 

untested cells with resource potential such that there is a 

50 percent probability that this amount or more exists in 

the assessment unit. This is the median value.

48. Number of Cells, F25: the estimated value of number of 

untested cells with resource potential such that there is a 

25 percent probability that this amount or more exists in 

the assessment unit.

49. Number of Cells, F5: the estimated value of number of 

untested cells with resource potential such that there is a 5 

percent probability that this amount or more exists in the 

assessment unit.
46 U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011

The Code List file contains the USGS numeric codes for 

provinces (4 digits), total petroleum systems (6 digits), and 

assessment units (8 digits). Codes for ecosystem names are in 

the Ecosystem Codes file. This table contains 3 columns. Data 

columns are as follows:

1. Code: USGS code number

2. Name: USGS area name

3. Name, Unit, and Code: the USGS area name, comma, 

space, the hierarchical unit name (province, total petroleum system, or assessment unit), and the USGS code 

number

The Ecosystem Codes file contains the USGS codes 

for ecosystem names. This table contains 3 columns. Data 

columns are as follows:

1. Ecosystem Code: USGS four-letter code

2. Ecosystem Name: ecosystem name

3. Ecosystem Name and Code: the ecosystem name followed 

by the USGS code in parentheses

The Cloud Plots file contains 110 columns. There are 

three records for each of the 139 AUs that were quantitatively 

assessed (one record for each of three variables: cell size, 

estimated ultimate recovery, and sweet spot percent). The .tab 

file includes the data variables described below. The Microsoft 

Excel version includes not only a worksheet with the variables 

described below but also separate worksheets and plots for the 

12 combinations of reservoir type and variable. In the plots, 

each blue line represents the distribution for a single assessment unit and the black diamond represents the mean of the 

distribution. Data columns for these files are as follows:

1. AU Number: USGS assessment-unit code number.

2. AU: USGS assessment unit name

3. Province Number: province code number.

4. Province: province name.

5. Reservoir Type: shale gas, coalbed gas, tight gas, or 

continuous oil.

6. Date: date of assessment.

7. Variable: cell size, EUR (estimated ultimate recovery), or sweet spot percent.

8. Fractile for Mean: the fractile that corresponds to the 

mean value of the distribution.

9. Mean: the mean value of the distribution.

10–110. F100 to F0: fractiles of the distribution. F95 represents a 95 percent chance of at least the amount 

tabulated. Other fractiles are defined similarly.

Central Energy Resources Science Center

Publishing support provided by: 

Denver Publishing Service Center

For more information concerning this publication, contact:

Center Director, USGS Central Energy Resources Science Center

Box 25046, Mail Stop 939

Denver, CO 80225

(303) 236-1647

Or visit the Central Energy Resources Science Center Web site at:

http://energy.usgs.gov/

This publication is available online at: 

http://dx.doi.org/10.3133/ds69MM
U.S. Continuous Resources Assessment Team—U.S. Geological Survey Assessments of Continuous (Unconventional) Oil and Gas Resources, 2000 to 2011—Digital Data Series 69–MM

ISSN 2327-638X (online)

ISSN 2333-0481 (CD/DVD)

http://dx.doi.org/10.3133/ds69MM