Scientific Inventory of Onshore Federal 

Lands’ Oil and Gas Resources and Reserves 

and the Extent and Nature of Restrictions or 

Impediments to Their Development 

THE PARADOX/SAN JUAN, UINTA/PICEANCE, GREATER 

GREEN RIVER, AND POWDER RIVER BASINS AND THE 

MONTANA THRUST BELT 

IN COMPLIANCE WITH THE ENERGY POLICY AND CONSERVATION ACT 

AMENDMENTS OF 2000, P.L. 106-469 §604 

Prepared by the 

U.S. Departments of the Interior, Agriculture and Energy 

January 2003 
BLM/WO/GI-03/002+3100 

JANUARY 2003 

The mention of trade names or commercial products does not constitute endorsement or 

recommendation for use by the Federal Government. 

THIS DOCUMENT AND SUPPORTING DATA CAN BE FOUND AT 

WWW.DOI.GOV 

AND 

WWW.BLM.GOV 

Compact disks (CDs) are available from the Bureau of Land 

Management 
AUTHORS AND CONTRIBUTORS 

Childs Cantey, Advanced Resources International, Inc. 

Ronald R. Charpentier, DOI-U.S. Geological Survey 

Christie M. Chester, Gonzales Consulting Services, Inc. 

W. Dean Crandell,* USDA, Forest Service

Melissa Dover, Premier Data Services, Inc.

Jeffrey Eppink, Advanced Resources International, Inc.

William Gewecke, DOI-Bureau of Land Management

Veronica Guandique, Advanced Resources International, Inc

H. William Hochheiser,* DOE

Brian Keightley, Advanced Resources International, Inc.

Timothy R. Klett, DOI-U.S. Geological Survey

Bob Johnson, Premier Data Services, Inc.

Keith Lewis, Premier Data Services, Inc.

Sam Limerick, Z, Inc.

Gary R. Long, DOE-Energy Information Administration

Xin (Lucy) Luo, Z, Inc.

Roy Lynch, Advanced Resources International, Inc.

Michael Marquis, Advanced Resources International, Inc.

David F. Morehouse,* DOE-Energy Information Administration

Jack Perrin, Z, Inc.

Brenda Pierce,* DOI-U.S. Geological Survey

Frances Pierce,* DOI-U.S. Geological Survey

Dan Rabinowitz, DOI-Bureau of Land Management

Christopher J. Schenk, DOI-U.S. Geological Survey 

Richard L. Watson,** DOI-Bureau of Land Management 

Suzanne Weedman,* DOI-U.S.Geological Survey 

Ron White, Premier Data Services, Inc. 

Robert Woerner, DOI-Bureau of Land Management 

John H. Wood, DOE-Energy Information Administration 

*Interagency Steering Committee Member 

**Interagency Steering Committee Chairman 
TABLE OF CONTENTS 

EXECUTIVE SUMMARY ....................................................................................x

THE MANDATE FROM CONGRESS ....................................................................................... x

THE PRESIDENT’S NATIONAL ENERGY POLICY DIRECTIVES ....................................... xi

METHODOLOGY ...................................................................................................................... xi

CONCLUSIONS ........................................................................................................................xii

COMPLIANCE WITH THE LAW ............................................................................................ xiii

1.0 INTRODUCTION.......................................................................................1-1

1.1 BACKGROUND....................................................................................................................1-1

1.2 ENERGY POLICY AND CONSERVATION ACT LEGISLATION...................................................1-4

1.3 THE NATIONAL ENERGY POLICY, MAY 2001 ......................................................................1-5

1.4 APPROACH.........................................................................................................................1-5

1.5 ROLES OF THE AGENCIES...................................................................................................1-6

1.6 INTENDED USE ...................................................................................................................1-6

1.7 PRODUCTS/FUTURE DIRECTION..........................................................................................1-7

2.0 METHODOLOGY......................................................................................2-1

2.1 PROCEDURES FOR COLLECTING AND ANALYZING LAND STATUS AND LEASE

STIPULATIONS....................................................................................................................2-2

2.1.1 LAND STATUS ..........................................................................................................2-2

2.1.2 LEASE STIPULATIONS...............................................................................................2-8

2.2 PROCEDURES FOR COLLECTING AND ANALYZING OIL AND GAS RESOURCE DATA............... 2-10

2.2.1 SOURCES OF OIL AND GAS RESOURCE DATA ......................................................... 2-10

2.2.2 OIL AND GAS RESOURCE DATA PREPARATION........................................................ 2-13

2.2.3 OIL AND GAS RESOURCE DATA-RELATED CAVEATS................................................. 2-25

2.3 PROCEDURES FOR COLLECTING AND ANALYZING PROVED OIL AND GAS RESERVES

DATA ............................................................................................................................... 2-25

2.3.1 SOURCES AND DATA-RELATED CAVEATS OF PROVED OIL AND GAS RESERVES

 DATA...................................................................................................................... 2-26

2.4 DATA INTEGRATION AND SPATIAL ANALYSIS.................................................................... 2-28

2.4.1 CATEGORIZATION FOR FEDERAL LAND STATUS AND LEASE STIPULATIONS.............. 2-28

2.4.2 ANALYTICAL MODELING OF FEDERAL LANDS AND RESOURCES ............................... 2-29

3.0 RESULTS..................................................................................................3-1

3.1 STUDY AREA FEATURES ....................................................................................................3-1

3.1.1 PARADOX/SAN JUAN BASIN ........................................................................................3-1

3.1.2 UINTA/PICEANCE BASIN .............................................................................................3-2

3.1.3 GREATER GREEN RIVER BASIN...................................................................................3-3

3.1.4 POWDER RIVER BASIN ...............................................................................................3-3

3.1.5 MONTANA THRUST BELT ............................................................................................3-4
APPENDICES 

APPENDIX 1 – ACRONYMS AND ABBREVIATIONS ...................................................................... A1-1

APPENDIX 2 – GLOSSARY OF TERMS........................................................................................ A2-1

APPENDIX 3 – LAND STATUS METHODOLOGY........................................................................... A3-1

APPENDIX 4 – LEASE STIPULATION DATA PREPARATION .......................................................... A4-1

APPENDIX 5 – U.S. GEOLOGICAL SURVEY METHODOLOGY FOR THE ASSESSMENT OF ..............

UNDISCOVERED OIL AND GAS RESOURCES ........................................................................ A5-1 

APPENDIX 6 – ENERGY INFORMATION ADMINISTRATION PROVED RESERVES ESTIMATION AND FIELD 

BOUNDARY CONSTRUCTION............................................................................................... A6-1 

APPENDIX 7 – GIS METHODOLOGY.......................................................................................... A7-1 

APPENDIX 8 – LAND MANAGEMENT AND RESOURCE DOCUMENTS USED IN THE EPCA INVENTORY 

......................................................................................................................................... A8-1 

APPENDIX 9 – EPCA INVENTORY STIPULATIONS - AVAILABLE ON THE CD-ROM AND THE WEBSITE 
FIGURES 

EXECUTIVE SUMMARY 

FIGURE ES-1 OUTLINE OF STUDY AREAS SHOWING FEDERAL LAND STATUS.....................................xiv

FIGURE ES-2 SUMMARY OF ALL EPCA INVENTORY AREAS – OIL AND NATURAL GAS RESOURCES 

AFFECTED BY ACCESS CATEGORIES.............................................................................................xvi

SECTION 1.0 – INTRODUCTION 

FIGURE 1A OUTLINE OF STUDY AREAS SHOWING FEDERAL LANDS....................................................1-3

SECTION 2.0 – METHODOLOGY 

FIGURE 2A FEDERAL LAND STATUS MAP – PARADOX/SAN JUAN STUDY AREA ..................................2-3

FIGURE 2B FEDERAL LAND STATUS MAP – UINTA/PICEANCE STUDY AREA ........................................2-4

FIGURE 2C FEDERAL LAND STATUS MAP – GREATER GREEN RIVER STUDY AREA.............................2-5

FIGURE 2D FEDERAL LAND STATUS MAP – POWDER RIVER STUDY AREA ..........................................2-6

FIGURE 2E FEDERAL LAND STATUS MAP – MONTANA THRUST BELT STUDY AREA .............................2-7

FIGURE 2F MAP VIEW OF RESOURCE PLAYS .....................................................................................2-11

FIGURE 2G CROSS-SECTION OF RESOURCE PLAYS...........................................................................2-12

FIGURE 2H CONVENTIONAL VS. CONTINUOUS ACCUMULATIONS........................................................2-13

FIGURE 2I TOTAL LIQUIDS MAP – PARADOX/SAN JUAN STUDY AREA...............................................2-15

FIGURE 2J TOTAL LIQUIDS MAP – UINTA/PICEANCE STUDY AREA .....................................................2-16

FIGURE 2K TOTAL LIQUIDS MAP – GREATER GREEN RIVER STUDY AREA .........................................2-17

FIGURE 2L TOTAL LIQUIDS MAP – POWDER RIVER STUDY AREA .......................................................2-18

FIGURE 2M TOTAL LIQUIDS MAP – MONTANA THRUST BELT STUDY AREA.........................................2-19

FIGURE 2N TOTAL GAS MAP – PARADOX/SAN JUAN STUDY AREA – CATEGORIES ...........................2-20

FIGURE 2O TOTAL GAS MAP – UINTA/PICEANCE STUDY AREA..........................................................2-21

FIGURE 2P TOTAL GAS MAP – GREATER GREEN RIVER STUDY AREA ...............................................2-22

FIGURE 2Q TOTAL GAS MAP – POWDER RIVER STUDY AREA ............................................................2-23
FIGURE 2R TOTAL GAS MAP – MONTANA THRUST BELT STUDY AREA ..............................................2-24

SECTION 3.0 – RESULTS 

FIGURE 3A SUMMARY OF ALL EPCA INVENTORY AREAS – OIL AND GAS RESOURCES AFFECTED BY 

ACCESS CATEGORIES ...................................................................................................................3-6

FIGURE 3B CHART OF RESULTS – LAND AND RESOURCES CATEGORIZATION, PARADOX/SAN JUAN 

STUDY AREA.................................................................................................................................3-8

FIGURE 3C CHART OF RESULTS – LAND AND RESOURCES CATEGORIZATION, UINTA/PICEANCE STUDY 

AREA ..........................................................................................................................................3-10

FIGURE 3D CHART OF RESULTS – LAND AND RESOURCES CATEGORIZATION, GREATER GREEN RIVER 

STUDY AREA...............................................................................................................................3-12

FIGURE 3E CHART OF RESULTS – LAND AND RESOURCES CATEGORIZATION, POWDER RIVER STUDY 

AREA ..........................................................................................................................................3-14

FIGURE 3F CHART OF RESULTS – LAND AND RESOURCES CATEGORIZATION, MONTANA THRUST BELT 

STUDY AREA...............................................................................................................................3-16

FIGURE 3G LAND ACCESS CATEGORIZATION MAP – PARADOX/SAN JUAN STUDY AREAS.................3-17

FIGURE 3H LAND ACCESS CATEGORIZATION MAP – UINTA/PICEANCE STUDY AREAS .......................3-18

FIGURE 3I LAND ACCESS CATEGORIZATION MAP – GREATER GREEN RIVER STUDY AREA ..............3-19

FIGURE 3J LAND ACCESS CATEGORIZATION MAP – POWDER RIVER STUDY AREA............................3-20

FIGURE 3K LAND ACCESS CATEGORIZATION MAP – MONTANA THRUST BELT STUDY AREA ..............3-21

FIGURE 3L ACCESS MAP, TOTAL LIQUIDS – PARADOX/SAN JUAN STUDY AREAS – 

CATEGORIES 1-10.......................................................................................................................3-22

FIGURE 3M ACCESS MAP, TOTAL LIQUIDS – UINTA/PICEANCE STUDY AREAS – 

CATEGORIES 1-10.......................................................................................................................3-23

FIGURE 3N ACCESS MAP, TOTAL LIQUIDS – GREATER GREEN RIVER STUDY AREA – 

CATEGORIES 1-10.......................................................................................................................3-24

FIGURE 3O ACCESS MAP, TOTAL LIQUIDS – POWDER RIVER STUDY AREA – CATEGORIES 1-10......3-25

FIGURE 3P ACCESS MAP, TOTAL LIQUIDS – MONTANA THRUST BELT STUDY AREA – 

CATEGORIES 1-10.......................................................................................................................3-26

FIGURE 3Q ACCESS MAP, TOTAL GAS – PARADOX/SAN JUAN STUDY AREAS – 

CATEGORIES 1-10.......................................................................................................................3-27

FIGURE 3R ACCESS MAP, TOTAL GAS – UINTA/PICEANCE STUDY AREAS – CATEGORIES 1-10 .......3-28
FIGURE 3S ACCESS MAP, TOTAL GAS – GREATER GREEN RIVER STUDY AREA – 

CATEGORIES 1-10.......................................................................................................................3-29

FIGURE 3T ACCESS MAP, TOTAL GAS – GREATER GREEN RIVER STUDY AREA – 

CATEGORIES 2-10.......................................................................................................................3-30

FIGURE 3U ACCESS MAP, TOTAL GAS – GREATER GREEN RIVER STUDY AREA – 

CATEGORIES 3-10.......................................................................................................................3-31

FIGURE 3V ACCESS MAP, TOTAL GAS – GREATER GREEN RIVER STUDY AREA – 

CATEGORIES 4-10.......................................................................................................................3-32

FIGURE 3W ACCESS MAP, TOTAL GAS – GREATER GREEN RIVER STUDY AREA – 

CATEGORIES 5-10.......................................................................................................................3-33

FIGURE 3X ACCESS MAP, TOTAL GAS – GREATER GREEN RIVER STUDY AREA – 

CATEGORIES 6-10.......................................................................................................................3-34

FIGURE 3Y ACCESS MAP, TOTAL GAS – GREATER GREEN RIVER STUDY AREA – 

CATEGORIES 7-10.......................................................................................................................3-35

FIGURE 3Z ACCESS MAP, TOTAL GAS – GREATER GREEN RIVER STUDY AREA – 

CATEGORIES 8-10.......................................................................................................................3-36

FIGURE 3AA ACCESS MAP, TOTAL GAS – GREATER GREEN RIVER STUDY AREA – 

CATEGORIES 9-10.......................................................................................................................3-37

FIGURE 3AB ACCESS MAP, TOTAL GAS – GREATER GREEN RIVER STUDY AREA – CATEGORY 10 ...3-38

FIGURE 3AC ACCESS MAP, TOTAL GAS – POWDER RIVER STUDY AREA – CATEGORIES 1-10 ..........3-39

FIGURE 3AD ACCESS MAP, TOTAL GAS – MONTANA THRUST BELT STUDY AREA – 

CATEGORIES 1-10.......................................................................................................................3-40
TABLES

TABLE ES-1 SUMMARY OF ALL EPCA INVENTORY AREAS – OIL AND NATURAL GAS RESOURCES 

AFFECTED BY ACCESS CATEGORIES ............................................................................... xv

TABLE 1A BLM AND FOREST SERVICE OFFICES CONTACTED FOR THE INVENTORY......................... 1-8

TABLE 2A UNDISCOVERED TECHNICALLY RECOVERABLE RESOURCES BY PLAY...............................2-14

TABLE 2B PROVED RESERVES SUMMARY STATISTICS.......................................................................2-28

TABLE 2C CATEGORIZATION HIERARCHY ..........................................................................................2-28

TABLE 3A SUMMARY OF ALL EPCA INVENTORY AREAS – OIL AND NATURAL GAS RESOURCES

AFFECTED BY ACCESS CATEGORIES .................................................................................3-5

TABLE 3B RESULTS – LAND AND RESOURCES CATEGORIZATION, PARADOX/SAN JUAN STUDY

AREAS...............................................................................................................................3-7

TABLE 3C RESULTS – LAND AND RESOURCES CATEGORIZATION, UINTA/PICEANCE STUDY AREA.....3-9

TABLE 3D RESULTS – LAND AND RESOURCES CATEGORIZATION, GREATER GREEN RIVER STUDY

AREA ..............................................................................................................................3-11

TABLE 3E RESULTS – LAND AND RESOURCES CATEGORIZATION, POWDER RIVER STUDY AREA

TABLE 3F RESULTS – LAND AND RESOURCES CATEGORIZATION, MONTANA THRUST BELT STUDY

.....3-13

AREA ..............................................................................................................................3-15
Executive Summary 

EXECUTIVE SUMMARY 

THE MANDATE FROM CONGRESS 

In November 2000, Congress passed and President Clinton signed the Energy Policy and 

Conservation Act Amendments of 2000 (EPCA) which directed the Secretary of the Interior, in 

consultation with the Secretaries of Agriculture and Energy, to conduct an inventory of oil and 

natural gas resources beneath Federal lands. 

“The inventory shall identify: 1) the United States Geological Survey reserve estimates of 

oil and gas resources underlying these lands; and 2) the extent and nature of any 

restrictions or impediments to the development of such resources.” 

This act marks the first time that Congress asked the Department to conduct a study of 

restrictions. 

On October 11, 2001, Congress provided its sense of priority for this study: 

“...In light of recent attacks on the United States that have underscored the potential for 

disruptions to America’s energy supply, the managers believe this project should be 

considered a top priority for the Department.” 

This report is a portion of the inventory of public oil and gas resources requested by Congress. 

This inventory is a comprehensive review of federal oil and gas resources and constraints on their 

development in five basins in the Interior West (Figure ES-1). These basins contain most of the 

onshore natural gas and much of the oil under Federal ownership within the 48 contiguous states. 

The EPCA requires that all onshore Federal lands be inventoried. The inventory will be 

expanded to include additional Federal lands and resources in the future. 

For the federal public-land managing agencies, principally the Department of the Interior’s 

Bureau of Land Management (BLM) and the Department of Agriculture’s Forest Service (USFS) 

and the citizens they serve, this inventory will serve primarily as a planning tool. It provides 

public-land managers with additional information to help them develop management plans for the 

lands under their jurisdiction. It allows them to identify areas of high oil or gas potential and to 

evaluate the effectiveness of available stipulations in balancing the responsible development of 

those resources with the protection of other valuable resources in the area. Conversely, it also 

allows resource managers to identify areas of low oil and gas potential but high potential for other 

resources (e.g. wildlife) or uses (e.g. recreation). In these situations, resource managers and the 

public can consider applying land management strategies that may promote increased protection 

of valuable resources or promotion of uses that might ordinarily conflict with oil or gas 

development. This report is a critical step in evaluating whether existing rules are appropriate, or 

need to be changed, either to provide greater protection to the environment or to promote 

appropriate resource development. 

x 
Executive Summary 

THE PRESIDENT’S NATIONAL ENERGY POLICY DIRECTIVES 

In May 2001, President Bush’s National Energy Policy directed that the EPCA inventory be 

expedited and that constraints to federal oil and gas leasing be reassessed and modified “where 

opportunities exist (consistent with the law, good environmental practice, and balanced use of 

other resources).” The National Energy Policy further directed that any reassessment of 

constraints be conducted “with full public consultation, especially with people in the region.” 

This inventory provides information regarding the geographical relationship between oil and gas 

resources and reserves and the constraints that govern their development. It is not a reassessment 

of any stipulations on the development of oil and gas resources. The public’s opportunity to 

participate in any reassessment of restrictions on oil and gas activities will occur in public-land 

planning or legislative processes. This inventory provides some basic information for any such 

processes. Additional information may be available from monitoring and scientific studies 

incorporated into adaptive management processes. 

The National Energy Policy provides an overview of the U.S. energy situation and alternatives 

available to increase energy efficiency and conservation, increase energy supplies, and protect the 

environment. At the direction of Congress, the present study focuses on the traditional energy 

resources of oil and natural gas beneath Federal lands*

. 

This inventory was prepared by staff of the Department of the Interior’s BLM and United States 

Geological Survey (USGS); the USFS; the Department of Energy (DOE); and the Energy 

Information Agency (EIA). The USGS provided the assessment of undiscovered, technically 

recoverable oil and natural gas resources beneath Federal lands based on commercially available 

data. The EIA contributed the analysis of proved reserves for Federal lands. The EIA data 

incorporates economic considerations not included in the USGS resource assessment. The DOE 

provided technical expertise to guide the design and analysis process for the inventory. The BLM 

and the USFS contributed their land-use planning information regarding oil and natural gas 

availability and leasing stipulations for the lands under their respective jurisdictions. 

METHODOLOGY 

This inventory is based on information that has been previously developed through both the 

scientific and planning processes of the contributing federal agencies. This information has often 

been provided to the public for its review and use. The information used in the present study is 

the best commercial and scientific information available. It has been compiled and analyzed by 

experts from the contributing agencies. The analytical methods and protocols used in the 

supporting studies have been subjected to rigorous review. The present study necessarily 

incorporates the assumptions, conditions, and limitations of the supporting scientific information 

as discussed in this report. This inventory is significant because for the first time information 

about oil and gas resources and reserves is overlain in a comprehensive manner with information 

about constraints on their recovery. 

* In recognition of the increased emphasis on the development of alternative energy resources in the 

National Energy Policy, the Department of Energy, in coordination with the Department of the Interior, is 

releasing a report, analogous to the present report, on the potential of particular federal lands to support 

alternative energy technologies such as wind, solar and biomass. 

xi 
Executive Summary 

A steering committee of the participating agencies identified five major geologic basins within 

the Interior West as priority geographic areas to inventory. The five basins are the Paradox/San 

Juan Basins in Colorado, Utah and New Mexico; the Uinta/Piceance Basins in Colorado and 

Utah; the Greater Green River Basin in Wyoming, Colorado and Utah; the Powder River Basin in 

Montana and Wyoming; and the Montana Thrust Belt in Montana. 

These basins were selected for the inventory for several reasons. First, these basins encompass 

nearly 104 million acres. About 59 million acres in this area are under federal management. This 

acreage includes split estate lands in which private surface lands are underlain by federal 

subsurface mineral rights. Second, these basins contain most of the onshore natural gas and much 

of the oil under public ownership within the 48 contiguous states. Third, the population of the 

Interior West is growing rapidly. Public lands in this region face increased demands for their use 

as sites for recreation, livestock grazing, forestry, open space, wildlife habitat, mining, and oil and 

gas production. 

The analysis of constraints to development centered on two factors that affect access to oil and 

gas resources on Federal lands. Those factors are (1) whether the lands are “open” or “closed” to 

leasing, and (2) the degree of access afforded by lease stipulations on “open” lands. All oil and 

gas leases have statutory and regulatory requirements. These stipulations can have many 

purposes ranging from the protection of environmental, social, historical, or cultural resources or 

values to the payment of rentals and royalties. 

Approximately 1,000 different lease stipulations are being applied by the land managing agencies 

in the five basins studied. To focus the analysis of constraints on oil and gas development, the 

inventory evaluated the extent of public lands (1) in which leasing is permitted under standard 

stipulations, and (2) in which leasing is permitted with increasing limitations on access, 

principally seasonal occupancy restrictions, and (3) in which oil and gas leasing is prohibited. 

The analysis also included consideration of exceptions to stipulations granted after a review of 

on-the-ground conditions and the use of modern technologies such as directional drilling. The ten 

categories of restrictions analyzed in this report include the complete range of access restrictions 

associated with oil and gas leasing in the five basins. 

CONCLUSIONS 

While the results of this analysis are different for each of the five basins studied, the cumulative 

results for all of the basins (Figure ES-2) can be summarized as follows (Federal lands, including 

split estate, in the five basins total 59,416,000 acres). 

1. Approximately 39 percent (23,091,000 acres) of the Federal land in these basins is 

available for oil and gas leasing with standard stipulations (Figure ES-2, “Leasing, 

Standard Lease Terms”). Based on resource estimates, these lands contain 57 percent of 

the technically recoverable oil and 63 percent of the technically recoverable gas in the 

basins. 

2. Approximately 25 percent (15,152,000 acres) of the Federal land is available for 

leasing with restrictions on oil and gas operations beyond standard stipulations (Figure 

ES-2, All other “Leasing” categories except “Leasing, Standard Lease Terms”). Based 

xii 
Executive Summary 

on resource estimates, these lands contain 28 percent of the technically recoverable oil 

and 25 percent of the technically recoverable gas in the basins. 

3. Approximately 36 percent (21,173,000 acres) of the Federal land in the five basins is 

not available for leasing (Figure ES-2, 3 “No Leasing” categories). Based on resource 

estimates, these lands contain about 15 percent of the technically recoverable oil and 12 

percent of the technically recoverable natural gas in the basins. 

COMPLIANCE WITH THE LAW 

All oil and gas leases on Federal land, even those with the least restrictive stipulations, are subject 

to full compliance with all substantive and procedural environmental laws and regulations. These 

laws include the National Environmental Policy Act, Clean Water Act, Clean Air Act, 

Endangered Species Act, and the National Historic Preservation Act. While compliance with 

these laws may delay, modify, or prohibit oil and gas activities, these laws represent the values 

and bounds Congress believed appropriate to place on Federal land managers for their 

stewardship of Federal lands. The present study was conducted at the request of Congress to 

provide information for it to consider in forthcoming deliberations on the role of Federal lands in 

the U.S. energy situation. 

It is important to emphasize that this inventory was prepared at the direction of Congress. It is 

not a decisionmaking document. The inventory identifies areas of high and low oil and gas 

potential and the nature of constraints to the development of those resources in five basins in the 

Interior West. Any reassessment of these restrictions on oil and gas activities will occur in 

public-land use planning or the legislative process, both of which are fully open to public 

participation and debate over the appropriate balance between resource protection and resource 

development. 

xiii 
Executive Summary 

Figure ES-1 Outline of Study Areas Showing Federal Land Status 

xiv 
Area Resources 

Total Liquids* Total Natural Gas** 

More Percent of Percent of Percent of 

Constrained Access Category (acres x1000) Federal (MMBbl)*** Federal (Bcf)**** Federal 

1. No Leasing (Statutory/Executive Order), (NLS) 10,068 16.9% 298 7.7% 9,035 6.5% 

2. No Leasing (Administrative), (NLA/LUP) 6,007 10.1% 116 3.0% 3,690 2.7% 

3. No Leasing (Administrative), (NLA) 5,098 8.6% 182 4.7% 3,185 2.3% 

4. Leasing, No Surface Occupancy (NSO) 2,714 4.6% 50 1.3% 3,120 2.3% 

5. Leasing, Cumulative Timing Limitations on Drilling >9 Months (TLs >9) 25 0.0% 3 0.1% 114 0.1% 

6. Leasing, Cumulative Timing Limitations on Drilling 6-9 Months (TLs 6-9) 2,521 4.2% 250 6.5% 5,549 4.0% 

7. Leasing, Cumulative Timing Limitations on Drilling 3-6 Months (TLs 3-6) 5,442 9.2% 528 13.7% 20,401 14.7% 

8. Leasing, Cumulative Timing Limitations on Drilling <3 Months (TLs <3) 697 1.2% 8 0.2% 733 0.5% 

9. Leasing, Controlled Surface Use (CSU) 3,753 6.3% 221 5.7% 6,080 4.4% Less 10. Leasing, Standard Lease Terms (SLTs) 23,091 38.9% 2,198 57.0% 86,566 62.5% Constrained Total, Federal Lands Including Split Estate 59,416 100.0% 3,854 100.0% 138,472 100.0% 

Total Non-Federal 44,256 2,455 87,668 

Total Study Area 103,672 6,309 226,141 

* Comprising oil, NGLs and liquids associated with natural gas reservoirs ***MMBbl -- Millions of Barrels Small rounding errors 

** Comprising associated dissolved and nonassociated natural gas ****Bcf -- Billion cubic feet may be present 

Table ES-1 Summary of All EPCA Inventory Areas – Oil and Natural Gas Resources Affected by Access Categories 

Executive Summary 

xv 
Percent of Federal and Split Estate Lands 

1% 

<1% 

4% 

5% 

9% 

10% 

17% 

39% 

6% 

9% 

No Leasing (Statutory/Executive Order) 

No Leasing (Administrative, Pending Land Use Plan) 

No Leasing (Administrative) 

Leasing, No Surface Occupancy 

Leasing, Cumulative Timing Limitations on Drilling >9 Months 

Leasing, Cumulative Timing Limitations on Drilling 6-9 Months 

Leasing, Cumulative Timing Limitations on Drilling 3-6 Months 

Leasing, Cumulative Timing Limitations on Drilling <3 Months 

Leasing, Controlled Surface Use 

Leasing, Standard Lease Terms 

Percent of Natural Gas Resources 

Percent of Oil Resources 3% 

2% 

3% 

8% 

5% 

6% 

14% 

6% 

57% 

2% 

<1% 1%

<1%

4% 

7% 

4% 

15% 

62% 

1% 

<1% 

Executive Summary

 Figure ES-2 Summary of All EPCA Inventory Areas – Oil and Natural Gas Resources Affected by Access Categories