GEOLOGICAL SURVEY CIRCULAR 860 

Estimates of Undiscovered Recoverable 

Conventional Resources of Oil and Gas 

in the United States 

Estimates of Undiscovered Recoverable 

Conventional Resources of Oil and Gas 

in the United States 

By G. l. Dolton, K. H. Carlson, R. R. Charpentier, 

A. B. Coury, R. A. Crovelli, 5. E. Frezon, 

A. 5. Khan, J. H. lister, R. H. McMullin, 

R. 5. Pike, R. B. Powers, E. W. Scott, and K. l. Varnes 

GEOLOGICAL SURVEY CIRCULAR 860 

1981 
United States Department of the Interior 

JAMES G. WATT, Secretary 

Geological Survey 

Dallas l. Peck, Director 

Library of Congress catalog-card No. 82-600010 

Free on application to Branch of Distribution, U.S. Geological Survey, 604 South Pickett Street, Alexandria, VA 22304 
CONTENTS 

Page 

Summary. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 1 

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

Acknowledgments............................. 4 

Sources of data............................. 5 

Commodities assessed........................ 5 

Definitions................................. 6 

Role of technology and economics in 

appraisal of recoverable resources........ 7 

Region and province locations and 

boundaries................................ 8 

Geologic framework.......................... 8 

Areas and volumes of sedimentary rocks •••••• 11 

Methodology of resource appraisal ••••••••••• 12 

Review of general methods ••••••••••••••••• 12 

Appraisal procedures for this report •••••• 14 

Methodology for processing probabilistic 

assessments of undiscovered hydrocarbon resources •••••••••••••••••••••••• 16 

Summary of methodology •••••••••••••••••••• 20 

Calculation of resources of natural gas 

liquids................................... 20 

Calculation of inferred reserves •••••••••••• 22 

Page 

Estimates of petroleum resources •••••••••••• 26 

Results of study •••••••••••••••••••••••••• 26 

Comparison of recent hydrocarbon 

resource estimates •••••••••••••••••••••• 29 

Conclusions ••••••••••••••••••••••••••••••••• 35 

Selected references ••••••••••••••••••••••••• 36 

Appendixes 

A. Aggregate probability 

distributions ••••••••••••••••••• 41 

B. Province index maps ••••••••••••••• 74 

C. Estimates of undiscovered 

recoverable oil and gas for 

onshore provinces ••••••••••••••• 76 

D. Estimates of undiscovered 

recoverable oil and gas for 

offshore provinces •••••••••••••• 78 

E. Estimated Federal ownership of 

oil and gas resources........... 80 

F. Estimation of inferred plus 

indicated reserves for the 

United States, by D. H. Root.... 81 

ILLUSTRATIONS 

Page 

Figure 1. Diagrammatic representation of Figures Page 

discovered and undiscovered 6-12. Graphs showing: 

recoverable quantities of 6. Age range of principal 

crude oil and natural gas producing and pro specin the United States ••••••••••• 3 tive reservoir rock 

2. Diagrammatic representation of units by petroleum 

petroleum resource Regions •••••••••••••••• 12 

classification ••••••••••••••••• 6 7. Example of finding-rate 

3. Maps showing petroleum Regions curves showing 

of the United States ••••••••••• 9 extrapolation of 

4. Generalized tectonic map of exponential and hyperNorth America •••••••••••••••••• 10 bolic curves ••••••••••• 15 

5. Map showing general areal 8. Typical conditional 

distribution of the oil probability distribuand gas fields of the tion of an undiscovered 

United States •••••••••••••••••• 11 recoverable resource ••• 17 

m 
Figure 9. 

10. 

11. 

12. 

Conditional probability 

distribution of undiscovered recoverable oil 

for the North Atlantic 

Shelf province ••••••••• 

Probability distribution of undiscovered 

recoverable oil for the 

North Atlantic Shelf 

province ••••••••••••••• 

Probability distribution of undiscovered 

recoverable oil for 

Xid-Atlantic Shelf 

province ••••••••••••••• 

Aggregate probability 

distribution of 

undiscovered recoverable oil for the 

combined North Atlantic 

and Mid-Atlantic 

Shelf area ••••••••••••• 

13-14. Maps showing estimated ranges 

and means of undiscovered 

Page 

18 

19 

21 

21 

recoverable resource by Region for: 

13. Crude oil................ 26 

Figure 

15-16. 

17-18. 

19-20. 

21-22. 

14. Natural gas •••••••••••••• 

Charts showing undiscovered 

recoverable resources by 

Region as percentage of the 

total estimate for 

the United States for: 

15. Crude oil •••••••••••••••• 

16. Natural gas •••••••••••••• 

Graphs showing estimates of 

discovered and undiscovered 

amounts of recoverable resources by Region for: 

17. Crude oil •••••••••••••••• 

18. Natural gas •••••••••••••• 

Graphs showing probability 

distributions of undiscovered 

recoverable resources for the 

United States for: 

19. Crude oil •••••••••••••••• 

20. Natural gas •••••••••••••• 

Graphs showing selected estimates 

of undiscovered recoverable 

resources for the United States 

for: 

21. Crude oil •••••••••••••••• 

22. Natural gas •••••••••••••• 

Page 

27 

28 

29 

30 

31 

32 

32 

33 

34 

TABLES 

Table 1. Production, reserves, and estimates of undiscovered recoverable resources of crude oil, 

natural gas, and natural gas 

liquids for the United States ••• 

2. Estimates of minimum economic 

field sizes offshore •••••••••••• 

3. Estimated areas and volumes of 

sedimentary rocks by Region ••••• 

Page 

2 

8 

13 

Tables4-7. Production, reserves, and estimates of undiscovered 

recoverable resources of 

the United States for: 

Page 

4. Crude oil •••••••••••••••••• 22 

5. Associated-dissolved gas ••• 23 

6. Non-associated gas ••••••••• 24 

7. Total gas •••••••••••••••••• 25 

8. Mean estimates of undiscovered 

recoverable resources of 

natural gas liquids in the 

United States ••••••••••••••••••• 35 
Estimates of Undiscovered Recoverable Conventional 

Resources of Oil and Gas in the United States 

By G. L. Dolton, K. H. Carlson, R. R. Charpentier, A. B. Coury, 

R. A. Crovelli, S. E. Frezon, A. S. Khan, J. H. Lister, R. H. McMullin, 

R. S. Pike, R. B. Powers, E. W. Scott, and K. L. Varnes 

SUMMARY 

In 1980, the U.S. Geological Survey (USGS) 

reappraised the undiscovered recoverable 

conventional resources of crude oil and natural 

gas in the United States. This investigation 

was in response to a national need for such 

estimates and took into account new geologic 

information and technology, economic changes, 

and new or refined methods of resource 

appraisal. The assessed resources were defined 

as those that could be extracted economical Zy 

under price-cost relationships and technological 

trends prevailing at the time of the 

assessment. UndiscoVePed PecoVePable PesouPces 

do not include quantities that may yet be found 

in new pay zones or extensions of existing 

fields. Also excluded from this assessement 

were resources from heavy oil deposits, tar 

deposits, oil shales, as well as gas in lowpermeablity "tight" reservoirs, gas occluded in 

coal, gas in geopressured shales and brines, and 

gas in natural gas hydrates (clathrates). 

For this study, the United States was 

divided into 15 Regions--11 onshore and 4 

offshore. These Regions correspond in general 

to those assessed in the USGS 1975 appraisal 

(Miller and others, 1975); however, the 

continental slopes were included in the present 

report, thereby increasing the offshore area 

assessed. The 15 Regions were further 

subdivided into 137 provinces that were the 

actual assessment units. Hawaii was not 

included because its volcanic terrane was not 

considered prospective for hydrocarbons. 

The assessments of undiscovered recoverable 

oil and gas were based fundamentally upon 

analysis and review of the province petroleum 

geology, exploration history, volumetric-yield 

determinations, finding-rate studies, and 

structural analyses. Because of the uncertainty 

in estimating undiscovered resources, the 

reported quantities include a range of values 

that correspond to different probability 

levels. Subjective probability procedures were 

used in their derivation. 

The undiscovered recoverable conventional 

oil resources for the United States are 

estimated to range from 64.3 to 105.1 billion 

barrels with a mean estimate of 82.6 billion 

barrels (table 1). Assessed gas resources range 

from 474.6 to 739.3 trillion cubic feet with a 

mean estimate of 593.8 trillion cubic feet 

(table 1). Each range corresponds to 95 percent 

and 5 percent probabilities of moPe than the 

respective amounts. 

When compared with the USGS estimates of 

1975, the mean estimate of oil for the entire 

United States has changed little, whereas the 

mean estimate of natural gas has increased. In 

making such a comparison, however, the reader 

should recognize that resources of the 

continental slopes are included in the current 

assessment, but were not included in the 197 5 

report. 

Figure shows the relationship between 

undiscovered recoverable quantities and those 

quantities that already have been found. For 

oil, the mean estimate of undiscovered resources 

is about 47 percent of what has been found. For 

natural gas, the mean estimate of undiscovered 

resources is 63 percent of what has been found. 

INTRODUCTION 

This report vresents a new appraisal of the 

undiscovered recoverable conventional resources 

of oil and gas in the United States. The 

appraisal, which was made in mid-1980 following 

an intensive period of study, incorporated data 

that were not available at the time of the 

previous USGS estimates (Miller and others, 

197 5). The new appraisals were based on new 

geologic information, results of continuing 

petroleum exploration, advances in petroleum 
Table 1.--P~oduction, pesePVes, and estimates of undiscovePed pecovePable ~esou~ces of c~ude oil, 

natuPal gas, and natuPal gas liquids fop the United States 

[All tabulated values are rounded numbers; therefore, values for production and reserves and for means 

of undiscovered resources, all of which are additive, may not be precisely so. Negl., negligible, 

less than or equal to 0.05 billion barrels of oil or 0.05 trillion cubic feet of gas; NA, not applicable; 

NE, not estimated] 

Identified resources 1 Undiscovered recoverable resources 

Cumulative 

production1 ~:::~~=:2 Indicated Inferred ~ow High 

Area 3F reserves reserves Fgs 5 Mean 

Crude oil (billion barrels) 

Onshore 

Alaska ••••••••••••••••• 1.2 8.7 0 5.0 2.5 14.6 6.9 

Lower 48 States •••••••• 111.4 15.9 3.6 16.8 36.1 62.0 47.7 

Entire onshore ••••••••• 112.6 24.7 3.6 21.8 41.7 71.0 54.6 

Offshore

4 Alaska •••••••••••••••• 0.7 0.2 0 0.1 4.6 24.2 12.2 

Lower 48 States •••••••• 7.5 3.0 Negl. 1.4 8.7 25.1 15.8 

Entire offshore •••••••• 8.2 3.1 Negl. 1.5 16.9 43.5 28.0 

Entire United States ••••• 120.7 27.8 3.6 23.4 64.3 105.1 82.6 

Natural gas (trillion cubic feet) 

Onshore 

Alaska ••••••••••••••••• 1.2 30.0 NA 4.4 19.8 62.3 36.6 

Lower 48 States •••••••• 519.3 123.3 NA 132.1 288.6 525.9 390.2 

Entire onshore ••••••••• 520.6 153.3 NA 136.5 322.5 567.9 426.8 

Offshore

4 Alaska •••••••••••••••• 0.6 2.0 NA 1.2 33.3 109.6 64.6 

Lower 48 States •••••••• 56.8 36.3 NA 39.8 66.1 148.2 102.4 

Entire offshore •••••••• 57.5 38.2 NA 41.0 117.4 230.6 167.0 

Entire United States ••••• 578.0 191.5 NA 177.5 474.6 739.3 593.8 

Natural gas liquids (billion barrels) 

Entire United States ••••• 19.1 5.7 NA 4.8 NE NE 17.7 

1cumulative production and reserves are as of December 31, 1979. Production and reserve figures 

were derived from API and AGA data (American Petroleum Institute, American Gas Association, and Canadian 

Petroleum Association, 1980), except for California where production and reserve data were taken from the 

California Division of Oil and Gas (1980) and the U.S. Geological Survey (Kalil, 1980). 

2Does not include gas in storage. 

3F95 denotes the 95th fractile; the probability of mo~e than the amount F95 is 95 percent. 

F5 is defined similarly. Fractile values are not additive. 

4rncludes quantities considered recoverable only if technology permits their exploitation beneath 

Arctic pack ice--a condition not yet met. 

technology, changes· in economic conditions, and 

refined methods of resource appraisal. 

The primary purpose of this report is to 

present estimates of the quantities of oil and 

gas that may be available for discovery and 

recovery. Secondary objectives are to describe 

briefly the geologic and mathematical 

methodologies used in the analyses and to 

provide an historical context for review of the 

results. Preliminary results of this study were 

released in USGS Open-File Report 81-192 (Dolton 

and others, 1981). 

The United States was divided into 137 

provinces, which included 80 onshore provinces 

and 57 offshore provinces on the continental 

2 

shelves and slopes. Estimates of undiscovered 

recoverable oil and gas resources were made for 

each province. Each evaluation involved the 

determination, from a geologic viewpoint, of the 

likelihood of the province having recoverable 

oil and gas, and the estimation of possible 

quantities of undiscovered recoverable oil and 

gas. Subjective probability methods were used. 

Both English and metric units are used in 

this report. For resource quantities English 

units are used exclusively. For most other 

quantities (such as drilling depths, areas, 

volumes) the traditionally used English units 

are given with metric equivalents in 

parentheses. For water depths, metric units are 
DISCOVERED UNDISCOVERED 

CRUDE OIL, IN BILLON BARRELS 

DISCOVERED UNDISCOVERED 

NATURAL GAS, IN TRILLION CUBIC FEET 

Fi gur e 1.--Discovered and undiscovered recoverabl e quantities of crude oi l and na t u r al ga s in 

the United States. Undiscovered values are mean estima t es. Crude oil in billion 

barrels; total natura l gas in t rillion cubic fee t. 

3 
more traditional and are used singly or with 

English equivalents. 

ACKNOWLEDGMENTS 

Integration of a vast quantity of 

information into this assessment of the Nation's 

petroleum resources required the involvement of 

many USGS scientists. State Geologists were 

invited through W. L. Fisher, Chairman, Liaison 

Committee of the Association of State 

Geologists, to participate. In addition to the 

authors, fifty USGS geologists aided in the data 

gathering and appraisal process. They were 

responsible for assembling data from 91 of the 

137 provinces assessed. We wish to thank the 

following people for their contributions: 

U.S. GEOLOGICAL SURVEY 

Geologic Division 

BPanch of Alaskan Geology, 

Menlo PaPk, CalifoPnia 

w. P. Brosge 

M. Churkin, Jr. 

R. L. Detterman 

A. A. Grantz 

G. Plafker 

AnchoPage, Alaska 

C. G. Mull 

BPanch of Pacific-APctic MaPine Geology, 

Menlo PaPk, CalifoPnia 

S. H. Clark, Jr. 

A. K. Cooper 

J. K. Crouch 

M. S. Marlow 

S. D. May 

D. W. Scholl 

P. D. Snavely, Jr. 

J. G. Vedder 

R. E. von Huene 

Seattle, Washington 

T. H. McCulloh 

BPanch of Atlantic-Gulf Coast MaPine Geology, 

CoPpus ChPisti, Texas 

R. G. Martin 

Woods Hole, Massachusetts 

W. P. Dillon 

J. A. Grow 

J. S. Schlee 

BPanch of Oil and Gas Resoupces, 

Cincinnati, Ohio 

R. C. Kepferle 

CoPpus ChPisti, Texas 

R. Q. Foote 

4 

DenVeP, ColoPado 

w. c. Butler 

M. c. Dalziel 

T. D. Fouch 

R. B. Halley 

J. D. Hendricks 

B. E. Law 

E. K. Maughan 

c. M. Molenaar 

w. J. Perry, Jr. 

D. D. Rice 

K. Robinson 

R. T. Ryder 

c. A. Sandberg 

c. w. Spencer 

Flagstaff, APizona 

T. J. Donovan 

Little Rock, APkansas 

B. R. Haley 

Menlo PaPk, CalifoPnia 

L. A. Beyer 

K. J. Bird 

T. R. Bruns 

M. A. Fisher 

D. G. Howell 

L. B. Magoon 

H. McLean 

J. A. Rykken 

Missoula, Montana 

J. A. Peterson 

Rapid City, South Dakota 

J. E. Fox 

Reston, ViPginia 

K. C. Bayer 

W. deWitt, Jr. 

L. D. Harris 

Woods Hole, Massachusetts 

M. M. Ball 

BPanch of SedimentaPy MinePals, 

DenVeP, ColoPado 

R. J. Rite 

The following individuals also contributed 

as advisors, consultants, or participants in the 

appraisal process: 

U.S. GEOLOGICAL SURVEY 

Geologic Division 

BPanch of Pacific-Apctic MaPine Geology, 

Menlo PaPk, CalifoPnia 

D. S. McCulloch 
BPanch of Paleontology and StPatigPaphy, 

Woods Hole, Massachusetts 

c. W. Poag 

BPanch of Oil and Gas ResouPces, 

Reston, ViPginia 

R. E. Mattick 

ConsePvation Division 

AnchoPage, Alaska 

I. F. Palmer, Jr. 

Los Angeles, Califopnia 

D. G. Griggs 

F. L. Webster 

MetaiPie, Louisiana 

F. T. Bryan 

J. Hewitt 

J. R. Pearcy 

Reston, ViPginia 

R. A. Kahler 

Washington, D.C. 

R. V. Amato 

R. D. Higgens 

S. S. Jacobson 

F. W. Lishman 

E. K. Simonis 

STATE OF CALIFORNIA, DEPARTMENT OF CONSERVATION 

SacPamento, Califopnia 

W. F. Guerard 

U.S. DEPARTMENT OF ENERGY, OFFICE OF APPLIED 

ANALYSIS 

Dallas, Texas 

T. M. Garland 

STATE OF LOUISIANA, OFFICE OF CONSERVATION 

Baton Rouge, Louisiana 

R. T. Sutton, 

Commissioner of Conservation 

OKLAHO~ GEOLOGICAL SURVEY 

NoPman, Oklahoma \~. E. Harrison 

Our technical support staff helped in the 

preparation of this report. J. H. Yenowine, Q. 

A. Wright, and B. L. Lane, provided valuable 

assistance in computing production statistics, 

planimetry, computer processing, the development 

of finding-rate curves, and other tasks 

necessary for the completion of this report. J. 

S. Wesley made literature searches and obtained 

references. D. D. Fox and D. K. Hobbs typed the 

manuscript. Tom Kostick provided drafting 

expertise in preparation of illustrations. In 

addition, we are indebted to J. D. Megeath and 

N. E. Pence for writing several computer 

programs, including graphics routines, and for 

revising a program originally based on the ideas 

5 

of G. M. Kaufman, Massachusetts Institute of 

Technology. We also wish to thank T. S. Dyman 

for his assistance in data retrieval. 

We particularly wish to thank the 

Conservation Division, U.S. Geological Survey, 

which made available unpublished material, 

including proprietary data, for many offshore 

areas. 

SOURCES OF DATA 

Primary sources of data for this study were 

direct contributions of U.S. Geological Survey 

geologists; published geologic information; 

published statistical data on petroleum 

exploration, reserves, and production; and 

unpublished U.S. Geological Survey material. 

The "Selected References" section lists the 

major published sources used for the nation as a 

whole; however, many significant reports and 

maps pertaining to specific regions are not 

included in this listing. Statistical data on 

production, reserves, and exploratory drilling 

were obtained primarily from the annual volumes 

on reserves and production of the American 

Petroleum Institute (API), American Gas 

Association (AGA), and Canadian Petroleum 

Association (CPA) (1967-1980), and from annual 

State statistical publications. Also used 

extensively were the oil and gas development 

yearbooks of the International Oil Scouts 

Association (1945-1978). 

Maps used on a national scale were the 

Geologic Map of the United States (King and 

Beikman, 1974), the Tectonic Map of North 

America (King, 1969), the Geothermal Gradient 

Map of North America (Geothermal Survey of North 

America Subcommittee of the American Association 

of Petroleum Geologists Research Committee, 

1976), the Basement Rock Map of the United 

States exclusive of Alaska and Hawaii (Bayley 

and Muehlberger, 1968), the Oil and Gas Fields 

of the United States exclusive of Alaska and 

Hawaii (Vlissides and Quirin, 1964), and the 

Terra Graphics' Oil and Gas Production Map of 

the United States (Smith, 1977). The National 

Atlas (U.S. Geological Survey, 1970) and land 

status and mineral status maps from the Bureau 

of Land Management were useful in the estimation 

of Federal and other ownership of oil and gas. 

Computer data bases included the Petroleum 

Information Corporation's Well History Control 

System and the Petroleum Data System. Some 

field and pool data were supplied by the Office 

of Applied Analysis, U.S. Department of Energy, 

Dallas, Texas. 

COMMODITIES ASSESSED 

Commodities included in this appraisal are 

crude oil, natural gas, and natural gas liquids 

that exist in conventional reservoirs. CPude 

oil is a mixture of hydrocarbons present in a 

liquid state in underground reservoir rocks and 

remaining in a liquid state as it is produced 
from wells. Natur>al gas is a mixture of gaseous 

hydrocarbons classified by occurrence into the 

following categories: 

Associated gas--free natural gas, occurring 

as a gas cap, in contact with and above an 

oil accumulation within the reservoir; 

Dissolved gas--natural gas dissolved in 

crude oil within the reservoir; and 

Non-associated gas--natural gas that is not 

associated with or not in contact with 

crude oil within a reservoir. 

Natur>al gas liquids (NGL) are "those portions of 

reservoir gas which are liquefied at the surface 

in lease separators, field facilities, or gas 

processing plants. Natural gas liquids include 

but are not limited to ethane, propane, butanes, 

pentanes, natural gasoline, and condensate" 

(American Petroleum Institute, 1976, p. 6). 

Both oil and natural gas normally include small 

quantities of various nonhydrocarbon impurities. 

Amounts of oil and gas are reported as 

standard stack tank barrels of crude oil (4 2 

gallons per barrel) and standard cubic feet of 

gas (14.73 pounds per square inch atmosphere and 

60°F), respectively. 

We have excluded unconventional resources 

from this assessment. Eliminated, therefore, 

were resources from heavy oil deposits, tar 

deposits, and oil shales; as well as gas in lowpermeability C'tight") reservoirs, gas occluded 

in coal, gas in geopressured shales and brines, 

and gas in natural gas hydrates (clathrates). 

However, small quantities of gas in lowpermeability reservoirs and limited quanti ties 

of heavy oil were incorporated as r>eser>Ves and 

pr>oduction in this report because they were not 

separated in the published production and 

IDENTIFIED RESOURCES 

Demonstrated 

Inferred 

Measured ·Indicated 

ECONOMIC Reserves 

1-------11-----'----

MARGINALLY 

ECONOMIC 

1------11------------------

SUBECONOMIC 

reserve data sources. 

Estimates of undiscovered crude oil and 

natural gas are as of mid-1980. 

DEFINITIONS 

Resource definitions published by the U.S. 

Bureau of Mines and the U.S. Geological Survey 

(McKelvey, 1973; U.S. Bure'au of Mines and U.S. 

Geological Survey, 1976, 1980) have been 

modified to apply specifically to crude oil, 

natural gas, and natural gas liquids. In some 

instances, definitions published by API ( 1976) 

were used with modification. The principal 

terms used in the present study are defined as 

follows, and, where appropriate, are identified 

in figure 2: 

Resour>ces.--Concentrations of naturally 

occurring liquid or gaseous hydrocarbons in the 

Earth's crust, some part of which is currently 

or potentially economically extractable. 

Economic (commer>cial) r>esouY'ces.--Those 

resources, both identified and undiscovered, 

that are economically extractable. In this 

study, price-cost relationships and technological trends prevailing at the time of 

assessment (1980) were assumed. Specifically 

excluded are quantities that may be technically 

extractable but not economically so. Therefore, 

excluded are deposits that are too small, too 

dispersed or too remote to be presently 

economic, and those portions of economic 

deposits that are non-extractable in a 

technologic sense. 

RecoveY'able Y'esouY'ces .--Identical to economic Y'esouY'ces. 

UNDISCOVERED RESOURCES 

u 

i 

0 

z 

0 

u 

w 

(!) 

z 

UJ 

c( 

w 

It 

u 

z 

> 

1-

..J 

m 

UJ 

c( 

w 

IL 

~---INCAEASING GEOLOGIC ASSURANCe:---------

Figure 2.--Petroleum resource classification (modified from U.S. Bureau of Mines and U.S. 

Geological Survey, 1976, 1980). Shaded area indicates the undiscovered recoverable 

resources estimated in the present study. 

6 
Ma~ginally economic ~esou~ces.--Resources 

not presently recoverable because of technologic 

and (or) economic factors, but that may become 

recoverable in the future. They are that part 

of the resources intermediate between the 

economic and subeconomic categories (fig. 2). 

Subeconomic ~esou~ces.--Resources that have 

an even more remote likelihood of extraction 

than do ma~ginally economic ~esou~ces. They are 

considered to be the largely unextractable 

portion of the original oil and gas in-place. 

Some part eventually may become recoverable as a 

result of major changes in technology and 

economic conditions; however, significant 

portions may never be recoverable. 

Identified ~esou~ces.--Resources whose 

location and quantity are known or are estimated 

from specific geologic evidence ~nd that include 

economic, marginally economic, and subeconomic 

components. Identified resources also can be 

subdivided (fig. 2) into measu~ed, indicated, 

and infe~~ed ~esou~ces, expressing varying 

degrees of geologic certainty. 

Measu~ed ~ese~ves.--That part of the 

economic identified resource that is estimated 

from geologic evidence supported directly by 

engineering measurements. Measured reserves 

here are equivalent to p~oved pesePves as 

defined by API (1976, p. 1). 

Indicated Pese~ves.--Reserves equivalent to 

API indicated additional ~esePves, that are 

defined as economic reserves in "known 

productive reservoirs in existing fields 

expected to respond to improved recovery 

techniques such as fluid injection where (a) an 

improved recovery technique has been installed 

but its effect cannot yet be fully evaluated; or 

(b) an improved technique has not been installed 

but knowledge of reservoir characteristics and 

the results of a known technique installed in a 

smiliar situation are available for use in the 

estimating procedure." (API, 1976, p. 1, 2.) 

Infe~~ed ~ese~ves.--That part of the 

identified economic resource that will be added 

to known fields through extensions, revisions, 

and new pay zones. (See p. 22 and Appendix F 

for derivation of inferred reserves used in this 

study.) 

UndiscoVePed ~esou~ces.--Resources, outside 

of known fields, estimated from broad geologic 

knowledge and theory. Also included are 

resources from undiscovered pools that occur as 

unrelated accumulations controlled by distinctly 

separate structural features and (or) 

stratigraphic conditions within areas of known 

fields. 

Oil o~ gas in-place.--The total oil or 

natural gas that is in underground reservoir 

rock without qualification as to what portion 

may be considered either currently or 

potentially extractable. Oil or gas in-place is 

essentially equivalent to total resources. 

PooZ.--A discrete natural accumulation of 

oil or gas in an underground reservoir, confined 

by barriers of water or impermeable rock, and 

characterized by a single pressure. system. Some 

7 

reporting agencies may define each pool as a 

separate field, as is done in Texas. 

Field.--A single pool or multiple pools all 

grouped on, or related to, a single structural 

and (or) stratigraphic feature. Individual 

pools in a single field may be separated 

vertically by impervious strata or laterally by 

local geologic barriers. 

ROLE OF TECHNOLOGY AND ECONOMICS IN 

APPRAISAL OF RECOVERABLE RESOURCES 

This study, which assesses the undiscovered recoverable hydrocarbon potential of the 

United States, considers only conventional 

accumulations of oil and gas. In production 

from conventional reservoirs, there are certain 

technologic and economic limitations to the 

amount of oil or gas in-place that can be 

recovered. Recovery of oil from a pool 

generally is limited to less than 60 percent of 

what is in place, and recovery of gas to less 

than 90 percent. On a national scale, recovery 

factors for oil and gas average about 32 percent 

and 80 percent, respectively. 

Additional technologic and economic 

constraints apply to the conditions under which 

exploration and production can take place. 

These conditions include the depth of drilling 

into the Earth's crust, the water depth 

offshore, availability of transportation and 

proximity to markets, and ice and other harsh 

physical environmental conditions. In addition, 

production rate and life expectancy of the 

reservoir are important factors. Drilling 

onshore now has reached depths in excess of 

30,000 ft (9,144 m), and deepest reported 

production is at 26,518 ft (8,083 m) (World Oil, 

1981a, b). Industry exploratory wells have been 

drilled in water depths approaching 5,000 ft 

(1,524 m); a drilling vessel is expected to be 

available soon to drill in water depths to 

13,000 ft (3,962 m) and to depths of 20,000 ft 

(6,096 m) below the sea floor. To date, the 

deepest water where production has been 

established is slightly more than 1,000 ft (305 

m). Continued extension of deep-water drilling 

and production technology can be expected as a 

result of current design and research programs. 

In estimating amounts of undiscovered 

~ecovePable (economic) oil and gas resources, 

certain assumptions must be made about economics 

and technology. We assumed that undiscovered 

resources of oil and gas will be Pecove~able 

under conditions represented by a continuation 

of price-cost relationships and technological 

trends that prevailed at the time of the 

assessment (1980). However, significant changes 

in price-cost relationships or fundamental 

changes in technology would affect estimates of 

Pecove~able resources. 

Onshore, the economic and technologic 

conditions assumed permitted the appraisal of 

recoverable resources on the basis of the size 

and type of fields that historically have been 

found, developed, and produced. Offshore, 
Table 2.--Estimates of minimum economic field sizes offshoPe 

[Gas-field sizes for the Gulf of Mexico and all oil-field sizes were provided by D. E. Kash, Conservation 

Division, U.S. Geological Survey, 1980, in a written communication. Non-associated gas-field sizes other 

than for the Gulf of Mexico were derived from the oil-field sizes by using a British thermal unit (BTU) 

equivalent of 6000 cubic feet of gas to one barrel of oil] 

Offshore areas 

Water Alaskan waters 

depth Gulf of Atlantic Ocean Pacific Southern Bering Chukchi Beaufort 

(meters) Mexico South Middle North Ocean Alaska 1 Sea Sea Sea 

Oil (million barrels) 

3-30 0.6-1.0 3-15 10-30 20-50 6-20 40-70 40-100 75-150 100-200 

30-100 1.0-2.0 5-25 20-80 30-100 10-45 50-100 50-125 100-200 150-300 

100-200 2.0-5.0 20-80 40-100 75-125 20-65 75-150 75-200 150-400 200-450 

)200 5-50 80-200 60-500 100-600 )30 125-250 125-300 )300 )400 

Non-associated gas (billion cubic feet) 

3-30 2-5 18-90 60-180 120-300 36-120 240-420 240-600 450-900 600-1200 

30-100 5-15 30-150 120-480 180-600 60-270 300-600 300-750 600-1200 900-1800 

100-200 15-30 120-480 240-600 450-750 120-390 450-900 450-1200 900-2400 1200-2700 

)200 30-200 480-1200" 360-3000 600-3600 )180 750-1500 750-1800 )1800 )2400 

1Gulf of Alaska, Kodiak, lower Cook Inlet, Shelikof Strait. 

recoverability often is uncertain due to the 

severe technologic and economic constraints 

imposed by the operating conditions. For 

guidelines, minimum field sizes for undiscovered 

recoverable resources offshore were arbitrarily 

assumed to be those summarized in table 2. In 

offshore northern Alaska, although economic 

field-size thresholds are indicated on table 2, 

even large accumulations beneath Arctic pack ice 

do not appear to be currently exploitable, 

although technologic advance may permit their 

development in the future. 

REGION AND PROVINCE LOCATIONS AND BOUNDARIES 

Regions and provinces were established to 

provide a basis for systematic appraisal. The 

15 Regions in this report (fig. 3), 11 onshore 

and 4 offshore, coincide in part with major 

geographic elements and are similar to those 

Regions used by Cram (1971) and by Miller and 

others (1975). The Regions in the present 

report were divided into 137 individual 

provinces that were the actual appraisal units. 

Province boundaries were based on natural 

geologic entities and may include a single 

dominant structural element or a number of 

contiguous elements. These boundaries follow 

State and county lines where possible, thus 

facilitating the use of production, reserve, and 

other data reported for political units by 

various State and Federal agencies and private 

compilers. Provinces were named for a 

structural, physiographic, or geographic feature 

within the province. 

8 

Offshore, province boundaries were drawn 

between shelf and slope at 200 m (656 ft) of 

water depth. Provinces of the continental slope 

extend seaward from a water depth of 200 m (656 

ft) to a depth of 2,400 m (7,874 ft) off Alaska 

and 2,500 m (8,202 ft) off the conterminous 

United States, unless the base of slope is at a 

shallower water depth. 

With reference to the international 

boundaries of the offshore regions, the United 

States has not yet resolved its offshore 

boundaries with its neighboring States. For 

purposes of this report, certain arbitrary 

assumptions had to be made about the extent of 

areas potentially subject to United States 

jurisdiction. The lines used in preparing this 

report are for purposes of illustration only, 

and do not necessarily reflect the position or 

views of the United States with respect to the 

location of the offshore boundaries between the 

United States and other States concerned. The 

United States expressly reserves its rights, and 

those of its nationals, in all areas in which 

the offshore boundary has not been resolved, and 

these illustrative lines are used without 

prejudice to such rights. 

GEOLOGIC FRAMEWORK 

The distribution of oil and gas resources 

in the United States is best understood within 

the framework of the geology of the North 

American continent. In essence, the continent 

consists of a relatively stable interior 

surrounded by zones of more highly deformed 
rocks (fig. 4). The Canadian Shield is an 

outcrop of the old, tectonically stable rocks 

that form the core of the continent. These 

igneous and metamorphic rocks are not 

prospective for hydrocarbons. In the Central 

Stable Interior, similar crystalline rocks are 

overlain by a relatively thin cover of 

sedimentary rock that fills a mnnber of 

structurally uncomplicated basins separated by 

broad arches. Regional deformation of the 

platform formed by these sedimentary rocks 

occurs in the Colorado Plateau and in parts of 

the Rocky Mountain System. Marginal basins of 

the Central Stable Interior tend to be deeper 

and structurally more complex than are those of 

the interior. 

The United States has not resolved its 

offshore boundaries with other States concerned. The lines on this chart are for purposes of illustration only, and do not necessarily reflect the position or views of the 

United States with respect to the boundary 

involved. 

0 

I 

0 

I 

500 MILES 

I 

500 KILOMETERS 

1 

Belts of rock deformed by intense folding 

and thrusting ring the central platform. These 

are the Cordilleran thrust belt that stretches 

from Alaska to Mexico, the Appalachian thrust 

belt, the Ouachita thrust belt, and the Marathon 

thrust belt (fig. 4). 

East of the Appalachian thrust belt are the 

crystalline rocks of the Piedmont. Mesozoic and 

Cenozoic sedimentary rocks of the Atlantic 

coastal plain lap onto the Piedmont forming a 

wedge of sedimentary rocks that thickens seaward 

along most of the Atlantic margin from a few 

hundred feet to more than 40,000 ft (12,192 

m). Mesozoic and Cenozoic sedimentary rocks 

also lap onto the Marathon and Ouachita thrust 

belts and form the Gulf Coastal Plain. These 

REGION 

NO. NAME 

1 Alaska 

1 A Alaska offshore 

2 Pacific Coast 

2A Pacific Coast offshore 

3 Colorado Plateau and Basin and Range 

4 Rocky Mountains and Northern Great Plains 

5 West Texas and Eastern New Mexico 

6 GulfCoast 

6A Gulf of Mexico 

7 Mid-continent 

8 Michigan Basin 

9 Eastern Interior 

10 Appalachians 

11 Atlantic Coast 

11A Atlantic Coast offshore 

Figure 3.--Petroleum Regions of the United States. 

9 
younger rocks thicken southward into the Gulf of 

1exico. 

\~est of the Cordilleran thrust belt, the 

major structural or physiographic elemen ts are 

the Basin and Range, parts of the Rocky Mountain 

System, and the Pacific Ma r gin System. The 

complex structures of this part of the continent 

indicate that it has been tectonically active 

through much of geologic time. 

Alaska is divided into two major structural 

and stratigraphic elements. The northern 

element consists of the Brooks Range, which is 

part of the Cordilleran thrust belt, and all 

areas north to the Arctic Ocean. The southern 

EXPLANATION 

Thrust belts 

LLLLJ Approximate base of continental slope 

element includes all of Alaska south of the 

Brooks Range and has a different and more 

complex geologic history than does the northern 

element. 

Areas of the United States that have 

produced oil and gas are shown in figure 5. 

Ages of productive and prospective rocks in each 

Region are shown in figure 6. The Central 

Stable Interior (Regions 5, 7-9, and parts of 4 

and 10) produces mainly from relatively old 

rocks of Paleozoic age. However, toward the 

western part of the Interior (parts of Regions 3 

and 4) petroleum from some of the intermontane 

basins is produced both from the older rocks of 

Figure 4.--Generalized tectonic map of North America. (Modified from King and Edmonston, 1972; 

and Hayes, 1976.) 

10 
Paleozoic age and from younger rocks of Mesozoic 

and Cenozoic age. 

Intense exploration for hydrocarbons in the 

thrust belts is relatively recent, but since 

1975 substantial discoveries in Paleozoic and 

Mesozoic rocks have been made in the WyomingUtah-Idaho area. The Appalachian, Marathon, and 

Ouachita thrust belts are being actively 

explored. 

A thick sequence of Mesozoic and Cenozoic 

sedimentary rocks characterizes both the Gulf 

and Atlantic margins. In the Gulf Coastal Plain 

(Region 6) and the adjoining Gulf of Mexico, 

these rocks have produced large quantities of 

hydrocarbons. Other than peninsular Florida, 

the Atlantic margin (Regions 11 and 11A) has not 

produced commercial amounts of petroleum to 

date; however, recent discoveries of gas and 

some oil have been made in Mesozoic rocks in the 

offshore mid-Atlantic Baltimore Canyon area. 

A series of productive sedimentary basins 

extends from New Mexico to Montana within the 

Rocky Mountain System and the Colorado Plateau 

(parts of Regions 3 and 4). Hydrocarbon 

production in this area is from rocks of 

Paleozoic through Cenozoic age. Except for the 

rich Cenozoic basins in California, there is 

The United States has not resolved its offshore 

boundaries with other States concerned. The lines 

on this chart are for purposes of illustration 

only, and do not necessarily reflect the position 

or views of the United States with respect to the 

boundary involved. 

.:r .. ~ 

+-----~-·-----·--· 

I 

little production through much of the far 

western United States. 

Alaska's production is from two major 

areas. Cook Inlet, in southern Alaska, produces 

from rocks of Cenozoic age, and the Arctic 

coastal plain of the North Slope, which includes 

the supergiant Prudhoe Bay Field, produces from 

rocks of Paleozoic, Mesozoic, and Cenozoic age. 

AREAS AND VOLUMES OF SEDIMENTARY ROCKS 

Areas and volumes of sedimentary rocks were 

determined for each province because the 

character, amount, and distribution of 

sedimentary fill in basins are fundamental 

factors relating to hydrocarbon potential. Some 

analytical procedures also are dependent upon 

such rock areas and volumes. Rocks that are 

deformed or altered to the point of being 

nonproductive for oil or gas were considered 

"basement" and were excluded. Igneous rocks 

were excluded except where they occur as 

incidental interlayers and intrusions. Areas 

and volumes of sedimentary rocks for the Regions 

of the United States are shown on table 3. 

Rocks deeper than 30,000 ft (9,144 m) were 

excluded from these tabulations on the basis of 

0 

I 

•- Oil and gas fields 

-- Regional boundaries 

I 

200 

200 

I 

I 

400 I 

400MILES 

I 

600 KILOMETERS 

Figure 5.--General areal distribution of oil and gas fields in the United States. (Modified 

from Vlissides and Quirin, 1964.) Names of numbered Regions are given in figure 3. 

11 
limiting factors of economics and drilling 

technology and the general degradation of 

reservoirs at depth. All calcula,ted volumes of 

sedimentary rocks were regarded as having 

petroleum potential, qualified by such geologic 

factors as reservoir quality, ability to 

generate hydrocarbons, and trapping potential. 

METHODOLOGY OF RESOURCE APPRAISAL 

Review of general methods 

Many methods have been developed for 

estimating undiscovered petroleum resources. 

The methods differ greatly with respect to 

strengths, weaknesses, amount of information 

needed, and applicability of results. There are 

various amounts of overlap between the methods 

and sometimes several methods are used in 

conjunction. The five major categories of 

resource appraisal methods are as follows: 

Time-ltratigraphic divisions 

Era System, series Age (million years) 1, 1A 

~ Holocene !~ ~~ c§t: Pleistocene 

2 

(.) Pliocene I 

"(5 

N 

0 Miocene c: 

CD ~ u ~ 

"€ Oligocene CD 

~ 

Eocene 

Paleocene 

63 I Cretaceous (.) 

·o 138---- N 

0 Jurassic Cl) 

CD 205 ~ Triassic 

,.._, 240 

Permian 

C: !II 

290 

Pennsylvanian 0 ::J ..co -330- ... ... ~CD Mississippian (.) u:t "(5 360- N 

0 Devonian 1-

~ 

~ 410- Q.. Silurian 

435 

Ordovician 

500-

Cambrian 

570 

Precambrian f------3,600~ 

I. ExtPapolation of HistoPical TPends 

These methods use statistical procedures to 

predict future discoveries by extrapolation 

of past performances. The most commonly 

used historical statistics are finding 

rates, that relate the discovered volume of 

hydrocarbons to the exploratory footage 

drilled, or the number of exploratory wells, 

or time. Hubbert (1974) and Moore (1966) 

used techniques of this category. 

II. APeal- OP VolumetPic-Yield Methods 

These methods involve the calculation of 

amounts of discovered hydrocarbon per unit 

area or volume of rock in well-explored 

districts and application of these ratios to 

areas or volumes of rock in less-explored 

districts. Variation among these approaches 

is due primarily to different assumptions 

Age range of principal producing and 

prospective rock units by Region (seefig.3) 

2,2A 3 4 5 6,6A 7 8 9 10 11, 

11A 

1-

.. 

. 

.. 

1-----

r-------

I 

.. 

~ 

J...-- .· I .··· 

f...----'- •. 

J...-- ~ 

1---------f------ r----,------,--

I · .. .. 

.. ·. 

! 

. 

. •· .. 

.. .... 

~ ••••••• .. 

.· ...... 

~ 

1-

r...--...---~ \--....-::.. 

Oldest known rocks in United States 

Figure 6. --Age range of principal producing and prospective reservoir rock units by petroleum 

Regions in the United States. 

12 
...... 

w 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

Table 3.--Estimated a~eas and volumes of sedimenta~y ~oeks by Region 

[Area is in thousands of s~are miles (mi 2) and square kilometers (km2). Volume is in thousands of cubic miles (mi 3) 

and cubic kilometers (km ). All tabulated values are rounded and may not be precisely additive due to rounding] 

Area Volume Area 

Region mi 2 km2 mi 3 km3 Region mi 2 km2 

Onshore Offshore 

Alaska 1 •••••••••••••••••••••••••••••• 163 421 481 2,006 1A Alaska: Shelf ••••••••••••• 527 1,364 

Pacific Coast •••••••••••••••••••••••• 142 367 228 949 Slope ••••••••••••• 170 441 

Colorado Plateau-Basin and Range ••••• 414 1,072 958 3,994 2A Pacific Coast: Shelf ••••••. • •••••• 19 49 

Rocky Mountains-Northern Slope ••••••••••••• 64 165 

Great Plains ••••••••••••••••••••••• 415 1,074 591 2,463 6A Gulf of Mexico: Shelf ••••••••••••• 124 322 

West Texas and Eastern New Mexico •••• 172 446 294 1,225 Slope ••••••••••••• 95 246 

Gulf Coast ••••••••••••••••••••••••••• 237 614 783 3,263 llA Atlantic Coast: Shelf ••••••••••••• 106 274 

Mid-continent •••••••••••••••••••••••• 401 1,039 332 1,382 Slope' ••••••••••••• 83 216 

Michigan Basin .•..••••••••••••.••••.. 122 316 109 455 Total shelf ••••••• 776 2,010 

Eastern Interior ..••••••••••••••••••• 193 501 240 1' 001 Total slope ••••••• 412 1,067 

Appalachians ••••••••••••••••••••••••• 193 500 493 2,054 

Atlantic Coast ••••••••••••••••••••••• 154 399 141 586 Total offshore •••• 1,188 3,077 

Total onshore ••••••••••••••••••••• 2,606 6,749 4,649 19,377 Onshore and offshore 

Total United States ••••••••••••••••••••• 3,794 9,826 

1Areas and volumes of sedimentary rocks in parts of interior Alaska were excluded because distribution of such rocks is too 

poorly known to estimate at this time. 

Volume 

. 3 km3 m~ 

657 2,740 

277 1,154 

35 145 

78 327 

635 2,647 

485 2,022 

245 1,020 

367 1,531 

1,572 6,552 

1,208 5,034 

2,780 11' 586 

7,429 30,963 
concerning the analogies between 

districts. Weeks (1950), Hendricks (1965), 

and Klemme (1980) discuss these procedures. 

III. Geochemical ~fatePial Balance Equations 

This is a special type of volumetric method 

in which estimates are made of the amounts 

of hydrocarbon generated, migrated, and 

trapped. This approach has been utilized 

mainly by Soviet geologists (for example, 

Neruchev, 1964). 

IV. Play Analysis Methods 

In these methods the amount of hydrocarbon 

in a play or prospect is determined by use 

of a reservoir engineering equation, taking 

into account geologic risk factors. Often 

the input for each variable (such as 

thickness of reservoir rocks and porosity) 

of this equation is in the form of a 

probability distribution that is known or 

estimated. Monte Carlo methods commonly are 

used to generate a probability distribution 

for the amount of hydrocarbon. The study of 

the National Petroleum Reserve in Alaska by 

the U.S. Department of the Interior (1979) 

used a play analysis. 

v. DiPect Subjective Assessment Methods 

In these methods, the quantity of resource 

is estimated directly on a subjective basis 

by an expert or team of experts. Geological 

information, and, generally, results of 

analyses by one or more of the other four 

methods, are reviewed and weighed. Delphi 

techniques commonly are employed. A direct 

subjective assessment method was used in the 

present report, as well as in Miller and 

others (1975). 

Appraisal Procedures for this Report 

In order to assess the total undiscovered 

recoverable crude oil and natural gas for the 

United States, the Nation was divid.ed into 

geologic provinces, both onshore and offshore, 

and each province was individually assessed. 

The estimates of resources were based 

fundamentally upon analysis and review of 

available geological, geophysical, drilling and 

production data. The estimates represent direct 

judgements of the petroleum potential of each 

province made by a team of geologists using 

subjective probability techniques to address the 

problem of uncertainty. 

Data Compilation 

Assembly of petroleum geology data was 

essential to the analysis and assessment. 

Available information concerning the petroleum 

geology, exploration status, and, where 

14 

applicable, the petroleum history of each 

province was compiled by the province geologist 

on a standard form. The compilation was 

reviewed by a regional coordinator who gave 

particular attention to the determination of 

area, thickness, and volume of sedimentary rock; 

and to the selection of analog basins. After 

review, the regional coordinator added field and 

reservoir data, production and reserve 

statistics, and other supplementary 

information. A short form was prepared that 

summarized the compiled data for each province. 

Data Analysis 

A number of geological and statistical 

analyses were applied to the assessed provinces, 

dependent upon the type and availability of 

data. The main categories of analysis used were 

volumetric-yield analysis and finding-rate 

studies. 

Volumetric-yield procedures were used to 

determine a range of hydrocarbon values useful 

as scaling factors. Yields from geologic 

analogs were used wherever possible. These 

analogs included internal analogs where known 

producibility was extrapolated into untested 

portions of a province, basin analogs using 

known yields of geologically similar basins, and 

structural or stratigraphic analogs using yields 

from structurally or stratigraphically similar 

basins. Potential yield categories as described 

by Klemme (1975) were applied selectively. 

Average, high, and low yields from the 

population of United States basins were also 

used as scaling factors without necessarily 

assuming geologic analogy. 

Finding-rate studies provided an analytical 

tool when adequate drilling and discovery 

information was available (fig. 7). Findingrate studies were used to describe the 

relationship between discovered amounts of 

hydrocarbons and exploratory footage drilled. 

Curves fit to these historic data allow for 

extrapolation from which undiscovered resources 

may be determined, assuming a continuation of 

existing exploration trends and successes. 

Resource values determined by projection of 

exponential and hyperbolic decline curves are 

illustrated in figure 7. 

Structures were counted and measured in 

those few· areas offshore where such data were 

available. These data, usually proprietary, 

were used for rough estimation of structural 

areas and closures, from which potential 

hydrocarbon volumes were calculated. Where 

available, detailed Outer Continental Shelf 

(OCS) prospect analyses completed by the 

Conservation Division, USGS, were used. 

ResouPce estimation 

A resource appraisal team of 6-12 

geologists met to make estimates of undiscovered 

resources for each of the provinces. The 
province geologist and the regional coordinator 

presented a summary of the geology and 

information pertinent to the evaluation. The 

data presented included an analysis and review 

of the province petroleum geology, exploration 

history, volumetric-yield procedures, findingrate studies, and structural analyses. Each 

member of the team then made an individual 

resource assessment for the province. Because 

of the uncertainty involved in appraising 

undiscovered resources, estimates of their 

quantities incorporated a range of values, and 

subjective probability procedures were used in 

their derivation. 

Oil and non-associated gas were separately 

assessed for each province. The assessment of 

each resource involved probabilistic estimation 

of two uncertain events: ( 1) the presence of 

the assessed hydrocarbon, and (2) its quantity, 

if present. 

As an example, in assessing undiscovered 

recoverable oil, an assessment must be made as 

to its presence within the province. Although 

the assumption of its presence may be made with 

confidence in producing provinces, this 

assumption cannot be made with certainty in 

areas where no economically recoverable 

0 

~ 

-

d 

Ul 

d~ ~-~ . a:O 

m 

:zO ol:J 

~ . _]0 

_J 

-U'1 

I:Dt'1 

-o 

_Jd 

-o o8 

d 

0 15 30 60 

petroleum has been discovered. In frontier 

areas where there has been little or no 

drilling, there is a risk that no recoverable 

petroleum exists. Therefore, the likelihood of 

any recoverable resource being present was 

estimated and was called the maPginal 

pPobability. A marginal probability was 

estimated for the event "recoverable oil 

present" and for the event "recoverable nonassociated gas present." Associated-dissolved 

gas has the same marginal probability as does 

the oil with which it occurs. 

Conditional upon recoverable resource being 

present, initial assessments were made for each 

of the assessed provinces as follows: 

1. 

2. 

3. 

A low resource estimate corresponding to a 

9 5-percent probability of moPe than that 

amount--this estimate is the 95th fractile 

CFg5). 

A high resource estimate corresponding to a 

5-percent probability of moPe than that 

amount--this estimate is the 

fractile (F5 ). 

A modal· ("most likely") estimate of 

quantity of resource associated with 

greatest likelihood of occurrence. 

5th 

the 

the 

A B 

~--L _____ _ 7S 90 105 120 135 150 

EXPLORATORY FOOTAGE (MILLION FEET) 

YEAR 

Figure 7. --Example of finding-rate curves showing extrapolation of exponential and hyperbolic 

curves. Historical data (data from Illinois basin) is from 1944 to 1976. The areas 

under the projected curves represent estimates of undiscovered recoverable oil to be 

found with the next 60 million feet of exploratory drilling. For the exponential 

curve A, the estimated amount of undiscovered recoverable oil is 0.038 billion 

barrels, and for the hyperbolic curve B, it is 0.115 billion barrels. 

15 
Two, and in some cases three, separate 

iterations of the procedures were made, 

following the introduction of new or recast 

data. Each repetition included a subjective 

probability assessment by each assessor. The 

estimates from the final iteration consisted of 

four sets corresponding to the marginal 

probability and the low, high, and modal 

values. The estimates were averaged across 

assessors for each set, and the resulting 

average marginal probablity and low, high, and 

modal values are the values that were processed 

using probabilistic methodology. 

Non-associated gas and associated-dissolved 

gas were individually assessed. Non-associated 

gas was estimated directly by the subjective 

probability methods described. In contrast, the 

associated-dissolved gas was calculated through 

use of gas-oil ratios that had been separately 

determined for each province. The gas-oil ratio 

used represents a consensus estimate of the 

appraisal team and was based, when possible, on 

extrapolation of historic gas-oil ratios. The 

gas-oil ratio was applied to the estimated 

quantities of undiscovered oil in order to 

derive a corresponding distribution of 

quantities of undiscovered associated-dissolved 

ga~D. 

Methodology for Processing Probabilistic 

Assessments of Undiscovered Hydrocarbon 

Resources 1 

The procedures described for estimating the 

undiscovered recoverable resources for each 

province involved subjective probabilities. For 

each province the resource appraisal team 

expressed judgments as estimates of a marginal 

probability, two fractiles (F95 and F5 ), and a 

modal value. These procedures were followed for 

all provinces, assuming independence among the 

provinces. The resources considered were oil, 

associated-dissolved gas, and non-associated 

gas. An assumption of independence was made 

between the two types of gas, whereas oil 

and associated-dissolved gas are completely 

dependent. 

MaPginal FPobability 

In the initial resource appraisal for a 

particular province, a condition was made that 

the resource was present in commercial 

quantities. Therefore, an estimate had to be 

made of the marginal probability--a subjective 

probability of the condition that the resource 

is actually present in recoverable quanti ties. 

These marginal probabilities were determined by 

the re~Dource appraisal team as described in the 

previous section. 

1

For a more detailed discussion of the 

probabilistic methodology for oil and gas 

resource apraisal, see Crovelli (1981). 

16 

For an example, consider the North Atlantic 

Shelf province. At the present time there has 

been no commercial oil found in the province. 

The chance of oil being present in commercial 

quantities was estimated to be 42 percent, that 

is, a marginal probability of 0.42. 

Conditional FPobability DistPibution 

The conditional low, high, and modal 

estimates of undiscovered recoverable resource 

described on p. 15 were used to determine a 

conditional probability distribution of the 

quantity of undiscovered recoverable resource 

for a province. The conditional probability 

distribution represents the judgmental 

probability distribution of the quantity of 

undiscovered recoverable resource conditioned on 

the recoverable resource being present. (This 

distribution is also referred to as the 

"unrisked" distribution.) A lognormal 

distribution was used as a probability model for 

the conditional probability distribution in a 

province. Because each pair of values among the 

three conditional estimates determines a 

lognormal distribution, there are three possible 

lognormal distributions. The fitted lognormal 

distribution with the largest standard deviation 

was chosen. 

A conditional probability distribution can 

be described in several ways. One standard 

approach, which was used in this study, is the 

conditional "more-than" cumulative distribution 

function (fig. 8 A) that gives the probability 

of mope than a specific amount. From this 

function, all the fractiles can be obtained 

easily. Another approach is the conditional 

probability density function ·(fig. 8 B) in which 

an area under its curve represents 

probability. The shape of the curve of this 

function helps to visualize where the 

probability is located. 

The conditional probability distribution of 

the undiscovered recoverable oil for the North 

Atlantic Shelf province is used for illustrative 

purposes in figure 9. The curve of the conditional moPe-than cumulative distribution 

function is shown in figure 9 A; the curve of 

the probability density function is given in 

figure 9 B. Some numerical characteristics (in 

billion barrels) of the lognormal distribution 

in figure 9 are the following: 95th fractile 

F 9 5=0. 18, 5th fractile F 5=3. 14, mean f-1-=1. 08, 

and standard deviation ~ =1.19. 

PPobability DistPibution 

The marginal probability of a resource for 

a province was applied to its corresponding 

conditional probability distribution to produce 

the judgmental probability distribution of the 

quantity of undiscovered recoverable resource. 

(This distribution also is referred to as the 

"unconditional" or "risked" distribution.) From 

the probability distribution, the final low 
z 

<t: 

::r:: 

1-

w 

a: 

0 

:2: 

LL 

0 

~ :::i 

iii 

<t: 

CD 

0 

a: 

0-

1.00~----------------------------------------------------------------------------------~ 0.95 

A 

B 

Fs 

QUANTITY OF RECOVERABLE RESOURCE 

QUANTITY OF RECOVERABLE RESOURCE 

Figure 8.--Typical conditional probability distribution of an 

shown as A, conditional moPe-than cumulative 

conditional probability density function. F95 probability of moPe than the amount is 95 percent. 

probability of moPe than the amount is 5 percent. 

undiscovered recoverable resource 

distribution function, and B, 

denotes the 95th fractile; the 

F5 denotes the 5th fractile; the 

17 
0 . ESTIMATES 

., MEAN - 1. 08 0 MEDIAN 0.73 z 95% 0. 18 <( 

:I: 

I- 75/. - 0.40 w UJ a: 50% 0.73 

0 d 

::iE 251. - 1. 32 LL 

0 5/. - 3. 14 ~ ~ MODE 0.33 

::J 

en d S.D. 1. 19 11:11 

<( 

Ill 

0 

a: 

Q. 

"' . 

0 

0 

d 

0 12.0 

Fss Fs 

BILLION BARRELS RECOVERABLE OIL A 

ESTIMATES 

MEAN - 1. 08 

MEDIAN 0.73 

95% - 0. 18 

75/. ~ 0.40 

SO% 0.73 

25% - 1. 32 

5/. 3. 14 

MODE 0.33 

s. o. - 1. 19 

BILLION BARRELS RECOVERABLE OIL 

Figure 9.--Conditional probability distribution of the undiscovered recoverable oil for the 

North Atlantic Shelf province expressed as A, conditional mor>e-than cumulative 

distribution function, and B, conditional probability density function. Estimates 

are mean, median, mode, standard deviation (S.D.), and fractiles that correspond to 

the percentages listed. 

18 
w 

Q:: 

QN 

:2:::~ 

u_ci 

C) 

~CD 

~~ ....... . ...lo 

-

m.,.. 

a:m 

(DO 

0 . Q::o 

Q..§ 

ci 

58% 

1\ 

\ 

\ 

\ 

~ 

. 

0.0 1.2 

0.0 I. 2 

"" 1'----,__ 

2.4 3.6 4.8 6.0 7.2 

BILLION BARRELS RECOVERABLE OIL 

2.1 3.6 1.8 6.0 7.2 

BILLION BARRELS RECOVERABLE OIL 

ESTIMATES 

MEAN - 0.45 

MEDIAN - 0.00 

95/: - 0.00 

75/: - 0.00 

sox - 0.00 

25/: - 0.59 

sx - 2.07 

MODE - 0.33 

S.D. - 0.94 

8.4 9.6 10.8 12.0 

E:STIMATES 

MEAN 0.45 

MEDIAN 0.00 

95/. 0.00 

75% 0.00 

50/. 0.00 

251. 0.59 

5% 2.07 

MODE 0.33 

s.o. 0.94 

8.1 9.6 10.8 12.0 

Figure 10.--Probability distribution of the undiscovered recoverable oil for the North Atlantic 

Shelf province expressed as A, moPe-than cumulative distribution function, and B, 

probability density function. A has the value of the marginal probability (0.42) 

at zero resource. B has a spike at zero resource of probability weight 1-0.42=0.58 

which represents the chance of no recoverable oil being present. Estimates are 

mean, median, mode, standard deviation (S.D.), and fractiles that correspond to 

percentages listed. 

19 
(F95 ), high (F5 ), and mean (~) estimates of the 

quantity of undiscovered recoverable resource 

were obtained for the province. The mean 

estimate is the mean of the probability 

distribution. 

Referring once again to the North Atlantic 

Shelf province, the probability distribution of 

the undiscovered recoverable oil is given in 

figure 10. Some numerical characteristics (in 

billion barrels) of this distribution are the 

following: 95th fractile F 95=0, 5th fractile 

F5=2.07, mean ~ 0.45, and standard deviation 

cr =0.94. Note that the curve of the mor>ethan cumulative distribution function (fig. 10 

A) has the value of the marginal probability 

(0.42) at zero. The probability density 

function (fig. 10 B) has a spike at zero of 

probability weight 1-0. 42=0. 58 which represents 

the chance of no oil being present in commercial 

quantities; this function helps to visualize 

where the probability is located. 

Aggr>egate Pr>obability Distr>ibution 

An aggregate probability distribution is 

the judgmental probability distribution of the 

total quantity of undiscovered recoverable 

resource in an area consisting of two or more 

provinces. Hence, an aggregate probability 

distribution is the convolution of two or more 

probability distributions; so that we have the 

distribution of the sum of two or more 

independent random variables. In which case, 

the mean value for an area equals the sum of the 

mean values for the provinces making up the 

area. Similarly, the variance (square of the 

standard deviation) for an area equals the sum 

of the variances. The aggregate marginal 

probability is the subjective probability of the 

resource being present in commercial quantities 

within the area (one or more provinces) 

considered. 

A Monte Carlo technique was used to 

aggregate the probability distributions of the 

provinces of an area to derive its aggregate 

probability distribution. From this 

distribution, the low (F95 ), high (F5 ), and mean 

( ~ ) estimates of the quantity of undiscovered 

recoverable resource were obtained for the 

area. An aggregate probability distribution of 

each resource was determined for each of several 

areas of the United States. Areas whose 

provinces were aggregated included the 15 

Regions, the onshore area, the offshore area, 

and the entire United States. Each area 

considered has four corresponding aggregations: oil, associated-dissolved gas, nonassociated gas, and total gas. 

For an illustrative example of an aggregation, a second province will be introduced and 

aggregated with the North Atlantic Shelf 

province discussed earlier. The probability 

distribution of the undiscovered recoverable oil 

for the Mid-Atlantic Shelf province is given in 

figure 11. Some numerical characteristics (in 

20 

billion barrels) of this distribution are the 

following: 95th fractile F95=0, 5th fractile 

F5=2.63, mean ~ =0.78, and standard deviation 

cr =1.03. Note that the marginal probability 

is equal to 69 percent. 

Let the combined North Atlantic and MidAtlantic Shelf area consist of the two 

provinces: North Atlantic Shelf (fig. 10) and 

Mid-Atlantic Shelf (fig. 11). The aggregate 

probability distribution represents the 

judgmental probability distribution of the total 

quantity of undiscovered recoverable oil for the 

combined area and is given in figure 12. Some 

numerical characteristics (in billion barrels) 

of this distribution are the following: 95th 

fractile F95=0, 5th fractile F5=3.76, mean 

~ =1.23, and standard deviation cr =1.39. 

There are important relationships between the 

provinces and the area as follows: 

Aggregate marginal probability: 

1-(1-0.42)(1-0.69)=0.82 

Aggregate mean: 

0. 45+0. 78=1. 23 

Aggregate standard deviation: 

Summary of Methodology 

Individual appraisals were made for each of 

the provinces using province petroleum geology, 

volumetric-yield procedures, exploration 

histories, and, in some provinces, finding-rate 

studies and structural analyses as a basis for 

subjective assessments of oil and gas. A 

lognormal distribution was fitted using low, 

high, and modal estimates to determine the 

conditional probability distribution for each 

province. By applying the marginal probability 

to the conditional probability distribution, the 

probability distribution of the quantity of 

undiscovered resource was established. To 

obtain total resource estimates for an area, the 

probability distributions for the provinces 

composing the area were aggregated by a Monte 

Carlo technique. From aggregate probability 

distributions, final estimates were obtained for 

areas including the 15 Regions, the onshore 

area, the offshore area, and the entire United 

States. 

CALCULATION OF RESOURCES OF NATURAL GAS LIQUIDS 

Natural gas liquids (NGL) are produced with 

both associated-dissolved and non-associated 

gas. The cumulative production of the two gas 

types and their corresponding NGL have been 

published by the AGA (API and others, 1967-

1980). From these stat is tics, historical 

production ratios of NGL to natural gas (barrels 
m . 

0 

-

~~ m- e· 

~0 

0...§ 

d 

. 

. 

\ 

\ 

\ 

~ 

\ 

0.0 0.9 

ESTIMATES 

MEAN - 0.78 

MEDIAN - 0.52 

95:.! - 0.00 

75:.! - 0.00 

SOY. - 0.52 

25:.! - 1. 09 

SZ - 2.63 

MODE - 0.44 

S.D. - 1. 03 

" 

~ i----

1.8 2.7 3.6 4.5 5.4 6.3 7.2 8.1 9.0 

BILLION BARRELS RECOVERABLE OIL 

Figure 11.--Probability distribution of the undiscovered recoverable oil for the Mid-Atlantic 

Shelf province. Estimates are mean, median, mode, standard deviation (S.D.), and 

fractiles that correspond to the percentages listed. 

z 

a: co :I:"' 

~"! 0 

w 

a=: 

0"~ 

1:::~ 

la....d 

0 

>-eCD 

~~ - . _)0 

-

m~ 

a: co 

m- o . ~0 

Q...§ 

d 

. 

~ 

\ . 

\ 

1\ 

. \ 

o.o 1.2 

ESTIMATES 

MEAN - 1. 23 

MEDIAN - 0.87 

95/. - 0.00 

75/. - 0.31 

50/. - 0.87 

25/. - 1. 71 

5/. - 3.76 

MODE - 0.37 

S.D. - 1. 39 

~~ r---._ 

2.4 3.6 4.8 6.0 7.2 8.4 9.6 10.8 12.0 

BILLION BARRELS RECOVERABLE OIL 

Figure 12.--Aggregate probability distribution of the undiscovered recoverable oil for the 

combined North Atlantic and Mid-Atlantic Shelf area. Estimates are mean, median, 

mode, standard deviation (S.D.), and fractiles that correspond to the percentages 

listed. 

21 
Table 4.-;Cpude oiZ--PPoduation, PesePves, and estimates of undisaovePed 

Peaovepable pesouPaes of the United States 

[All tabulated values are rounded numbers; therefore, values for production and reserves and for means of undiscovered 

resources, all of which are additive, may not be precisely so. Values shown are in billions of barrels. Negl., 

negligible, less than or equal to 0.05 billion barrels of oil] 

Identified resources 1 Undiscovered recoverable resources 

Petroleum Region 

1 Alaska ••••••••••••••••••• 2 Pacific Coast •••••••••••• 

3 Colorado Plateau and 

Basin and Range •••••••• 

4 Rocky Mountains and 

northern Great Plains •• 

5 West Texas and eastern 

New Mexico ••••••••••••• 

6 Gulf Coast ••••••••••••••• 

7 Mid-continent •••••••••••• 

8 Michigan Basin ••••••••••• 

9 Eastern Interior ••••••••• 

10 Appalachians ••••••••••••• 

11 Atlantic Coast •• ••••. •••• Entire onshore ••••••••••••••• 

lA Alaska3 ••••••••••••••••• 

2A Pacific Coast ••••••••••• 

6A Gulf of Mexico •••••••••• 

llA Atlantic Coast •••••••••• 

Entire shelf ••••••••••••••••• 

lA Alaska3 ••••••••••••••••• 

2A Pacific Coast ••••••••••• 

6A Gulf of Mexico •••••••••• 

llA Atlantic Coast •••••••••• 

Entire slope ••••••••••••••••• 

lA Alaska3 ••••••••••••••••• 

2A Pacific Coast ••••••••••• 

6A Gulf of Mexico •••••••••• 

llA Atlantic Coast •••••••••• 

Entire offshore •••••••••••••• 

Cumulative 

production1 

1.2 

16 .s 

1.7 

6.9 

25.2 

34.9 

18.2 

0.8 

4.3 

2.8 

0.1 

112.6 

0.7 

1.9 

5.6 

0 

8.2 

0 

0 

Negl. 

0 

0 

0.7 

1.9 

5.6 

0 

8.2 

Entire United States......... 120.7 

Measured Indicated Inferred 

reserves 

8.7 

3.2 

0.3 

1.1 

5.4 

3.8 

1.5 

0.2 

0.2 

0.2 

Negl. 

24.7 

0.2 

41.2 

1.7 

0 

3.1 

0 

0 

No data4 

0 

0 

reserves reserves 

Onshore 

0 

1.6 

Negl. 

0.2 

1. 3 

0.2 

0.2 

Negl. 

Negl. 

Negl. 

0 

3.6 

s.o 

1.2 

1.0 

2.9 

4.0 

5.3 

1.4 

0.8 

0.1 

0.1 

0.1 

21.8 

Offshore--shelf 

0 

0 

Negl. 4 

0 

Negl. 

0.1 

o.s 

41.0 

0 

1.5 

Offshore--slope 

0 

40 

0 

0 

0 

0 

0 

No data4 

0 

0 

2.5 

2.1 

6.9 

6.0 

2.7 

3.6 

2.3 

0.3 

0.3 

0.1 

0.1 

41.7 

3.8 

0.6 

1.3 

0 

9.2 

0 

0.6 

0.9 

0 

4.2 

Offshore--combined shelf and slope 

0.2 

1.2 

1.7 

0 

3.1 

27.8 

0 

0 

Negl. 

0 

Negl. 

0.1 

o.s 

1.0 

0 

1.5 

Combined onshore and offshore 

3.6 23.4 

4.6 

1.7 

3.1 

1. 1 

16.9 

64.3 

14.6 

7.9 

25.9 

14.0 

9.4 

12.6 

7.7 

2.7 

1.9 

1.5 

0.8 

71.0 

22.0 

3.0 

7.9 

3.9 

30.2 

5.2 

6.0 

5.2 

10.7 

19.2 

24.2 

7.9 

11.1 

12.9 

43.5 

105.1 

6.9 

4.4 

14.2 

9.4 

5.4 

7.1 

4.4 

1.1 

0.9 

0.6 

0.3 

54.6 

10.8 

1.5 

4.0 

1.3 

17.6 

1.4 

2.4 

2.5 

4.1 

10.4 

12.2 

3.8 

6.5 

5.4 

28.0 

82.6 

1cumulative production and reserves are as of December 31, 1979. Production and reserve figures were derived 

from API and AGA data (American Petroleum Institute, American Gas Association, and Canadian Petroleum Association, 

1980) except for California for which production and reserve data were taken from California Division of Oil and Gas 

(1980) and the U.S. Geological Survey (Kalil, 1980). 

2F95 denotes the 95th fractile; the probability of mope than the amount F95 is 95 percent. F5 is defined 

similarly. Fractile values are not additive. 

3Includes quantities considered recoverable only if technology permits their exploitation beneath Arctic pack 

ice--a condition not yet met. 

4.3 

2.0 

8.0 

2.6 

2.2 

2.8 

1.8 

0.8 

0.6 

o.s 

0.3 

10.5 

6.4 

0.8 

2.1 

1.4 

6.9 

2.3 

2.0 

1.4 

3.6 

4.9 

6.8 

2.2 

2.5 

3.9 

8.5 

13.4 

4API and AGA reserve data for the Gulf of Mexico are not available within separate shelf and slope classifications. 

However, the declared reserves probably represent only the shelf and are so treated. 

ratios were used; 

associated-dissolved 

associated gas. 

these 

gas and 

are 52.21:1 

25.23: 1 for 

CALCULATION OF INFERRED RESERVES 

for 

nonNGL/million cubic feet gas) were calculated for 

each of the two gas types for various areas of 

the country. The estimates of undiscovered 

recoverable NGL were obtained by multiplying 

these ratios by the corresponding mean estimates 

of undiscovered recoverable natural gas of each 

type. Where historical data were not available, 

or where future development might substantially 

alter the current ratio, the national average 

Estimates of the amounts of oil and gas 

credited to the year of discovery by the API and 

others (1967-1980) tend to increase through time 

22 
Table 5.--Assoeiated-dissoZved gas--PPoduetion, PesePVes, and estimates of undiseovePed 

PeeovepabZe PesouPees of the United States 

[All tabulated values are rounded numbers; therefore, values for production and reserves and for means of undiscovered 

resources, all of which are additive, may not be precisely so. Values shown are in trillion cubic feet. Negl., 

negligible, less than or equal to 0.05 trillion cubic feet of gas] 

Identified resources 1•2 

Measured Inferred 

Undiscovered recoverable resources 

Petroleum Region 

Cumulative 

production1 reserves reserves ~ow H~gh Standard F95 F5 Mean deviation 

Onshore 

1 Alaska ••••••••••••••••••••••• 0.1 26.5 2.1 5.3 36.4 15.8 

2 Pacific Coast •••••••••••••••• 19.4 2.6 0.5 2.3 9.3 5.0 

3 Colorado Plateau and 

Basin and Range •••••••••••• 1.7 0.4 0.1 14.1 51.1 28.5 

4 Rocky Mountains and 

northern Great Plains •••••• 5.1 1.7 0.3 6.7 17.3 11.2 

s West Texas and eastern 

New Mexico ••••••••••••••••• 43.9 7.2 3.4 4.8 18.0 10.0 

6 Gulf Coast ••••••••••••••••••• S2.0 9.6 4.8 S.2 22.S 11.8 

7 Mid-continent •••••••••••••.•• 32.6 2.6 1.0 4.2 16.4 8.8 

8 Michigan Basin ••••••••••••••• 0.6 0.5 0.2 0.4 3.2 1.4 

9 Eastern Interior ••••••••••••• 1.6 Negl. 0.1 0.2 1.2 0.6 

10 Appalachians ••••••••••••••••• 1.7 0.2 Neg!. 0.1 1. 2 o.s 

11 Atlantic Coast ••••••••••••••• Negl. Neg!. Negl. Negl. 0.1 Negl. 

Entire onshore ••••••••••••••••••• 1S8. 7 S1.2 12.4 68.2 126.3 93.6 

Offshore--shelf 

lA Alaska4 •••••••••••••••••••••• 0.1 S0.2 Negl. 5. 7 3S.l 16.7 

2A Pacific Coast •••••••••••••••• 1.1 61.9 5o.4 o.s 2.8 1.4 

6A Gulf of Mexico ••••••••••••••• 8.1 4.2 6o.3 2.2 11.0 S.7 

11A Atlantic Coast •••••••••••••• • 0 0 0 0 4.6 1.6 

Entire shelf •••••••••••••••••••••• 9.3 6.3 0.7 12.8 44.6 2S.3 

Offshore--slope 

lA Alaska4 •••••••••••••••••••••• 0 0 0 0 7.9 2.2 

2A Pacific Coast •••••••••••••••• 0 so so 0.6 7.6 2.7 

6A Gulf of Mexico ••••••••••••••• Neg!. No data6 No data6 1.6 8.9 4.4 

11A Atlantic Coast ••••••••••••••• 0 0 0 0 13.0 4.8 

Entire slope •••••••••••••••••••••• 0 0 0 S.9 26.2 14.2 

Offshore--combined shelf and slope 

1A Alaska4 •••••••••••••••••••••• 0.1 S0.2 ~egl. 6.7 37.6 18.9 

2A Pacific Coast •••••••••••••••• 1.1 1.9 0.4 1. 7 8.9 4.1 

6A Gulf of Mexico ••••••••••••••• 8.1 4.2 0.3 S.3 16.9 10.1 

11A Atlantic Coast ••••••••••••••• 0 0 0 1.2 15.0 6.4 

Entire offshore ••••••••••••••••••• 9.3 6.3 0.7 23.3 60.8 39.4 

Combined onshore and offshore 

Entire United States •••••••••••••• 167.9 S7.5 13.1 101.0 171.8 133.0 

1cumulative production and reserves are as of December 31, 1979. Production and reserve figures were derived 

from API and AGA data (American Petroleum Institute, American Gas Association, and Canadian Petroleum Association, 

1980) except for California for which production and reserve data were taken from California Division of Oil and Gas 

(1980) and the U.S. Geological Survey (Kalil, 1980). 

2noes not include gas in storage. 

3F9s denotes the 95th fractile; the probability of moPe than the amount Fgs is 9S percent. Fs is defined 

similarly. Fractile values are not additive. 

4Includes quantities considered recoverable only if technology permits their exploitation beneath Arctic pack 

ice--a condition not yet met. 

10.9 

2.4 

13.9 

3.S 

4.2 

S.9 

4.0 

1.0 

0.4 

0.4 

Neg!. 

20.0 

10.0 

0.8 

2.8 

1.7 

10.S 

3.7 

2.4 

2.4 

4.2 

6.6 

10.6 

2.6 

3.7 

4.6 

12.4 

23.5 

SEstimates of non-associated and associated-dissolved gas reserves in California Federal offshore ateas are not recorded 

separately. All gas in these areas is treated here as associated-dissolved. 

6API and AGA reserve data for the Gulf of Mexico are not available within separate shelf and slope 

classifications. However, the declared reserves probably represent only the shelf and are so treated. 

as a consequence of revisions, extensions, and 

additions of new reservoirs to old fields. That 

part of the economic resources that will be 

added as a result of this growth in the future 

23 

is infePPed PesePves. 

Estimates of ultimate production from known 

fields, including growth, as of the end of 1978 

were calculated by D. H. Root (Appendix F). We 
Table A. --Non-associLltc?d gas--P-roduction, -reser-ves, cmd estimates of w1cH scoL'eN:,_i 

r-ecover-abl2 Pesour-ces of the United Statec" 

[All tabulated values are rounded n~bers; therefore, values for production and reserves and for means of undiscovered 

resources, all of which are additive, may not be precisely so. Values shown are in trill ion cubic feet. Negl., 

negligible, less than or equal to 0.05 trillion cubic feet of gas] 

Pet role~ Region 

Alaska ••••••••••••••••••••••• 

Pacific Coast •••••••••••••••• 

Colorado Plateau and 

Basin and Range •••••••••••• 

Rocky Mountains and 

northern Great Plains •••••• 

West Texas and eastern 

Cumulative 

production 1 

l.l 

7.6 

13. 3 

8.1 

New Mexico................ 26.8 

Gulf Coast ••••••••••••••••••• 176.4 

~lid-continent................ 95.2 

}1ichigan Basin............... 0. 7 

Eastern Interior............. U. :2 

10 Appalachians................. 3:2.5 

ll Atlantic Coast............... 0 

Entire onshore................... 361.9 

1A 

2A 

6A 

l1A 

l\laska 4 ••••••••••• , ••• , ••.•• 

Pacific Coast ••••••••••••••• 

Gulf of ~lexico •••••••••••••• 

Atlantic Coast •••••••••••••• 

Entire shelf ••••••••••••••••••••• 

L\ Alaska 4 ••••••••••••••••••••• 

2A Pacific Coast ••••••••••••••• 

6A Gulf of rlexico •••••••••••••• 

l1A Atlantic Coast •••••••••••••• 

Entire slope ••••••••••••••••••.•• 

0.5 

0.4 

47.2 

0 

48.2 

l A Alaska 4 • • • • • • • • • • • • • • • • • • • • • 0. 5 

2A Pacific Coast............... 0.4 

6A Gulf of Hexico •••••••••••••• 47.2 

lL\ Atlantic Coast.............. 0 

Entire offshore.................. 48.2 

Entire United States............. 410.1 

Identified 

>leasured 

reserves 

3. 5 

1.7 

ll.O 

5.4 

8.8 

35.7 

:29.4 

11.6 

Negl. 

6.0 

1112.1) 

l ? resources ,._ 

Inferred 

reserves 

Onshore 

:2.3 

3. 3 

4.~ 

5.:2 

14. 7 

69.5 

17. 9 

11.8 

Negl. 

5.8 

() 

124 .l 

Offshore--shelf 

1.7 

_ Negl. 5 

6 30:2 

0 

31.9 

N~~t. 5 639.1 

u 

40.3 

Offshore--slope 

II 

\I 

:\o data 6 

II 

IJ 

511 

No~data 6 

I) 

111. n 

4.4 

30. 2 

19.8 

13.9 

45.7 

15.8 

0.9 

0.8 

6.0 

235.6 

16.U 

1).2 

17.4 

1.1 

SO.h 

C1. 8 

7.6 

II 

17.2 

Offshore--combined shelf and slope 

1.7 1.1 19.1 

Negl. 5 :-Jegl. 5 l ') 

30.2 39. 1 32. 5 

0 6.5 

31.9 40.3 80.3 

Combined onshore and offshor" 

134.0 164 • .4 3 511.11 

Undiscovered recoverable resources 

High Standard 3F5 ;lean deviation 

37.0 20.7 il.9 

19.5 9.6 4.9 

lll. l 61.6 2h. 3 

56.2 34.5 12. l 

67.3 3:2.8 17. 3 

228.3 112.6 113.3 

b8.9 35. 7 lil.O 

9.3 3.8 3.0 

4.4 :2. l 1.2 

43.9 19.7 13.2 

u. 3 1]. l 0. 3 

468.4 3 31.2 75.9 

78.4 40.7 21.4 

3. 5 1.:2 1.2 

74.1 39.6 18.3 

15. 6 h.7 4.8 

139 .l 88.2 28.6 

15.2 5.1 I 11.7 

4.9 l.h 1.7 

47.7 ) ~ ? 13. b 

27.0 111. b 8.6 

7l.b 39.4 :21}.11 

89.1 4 5. 7 24.4 

7 .II 2.8 2.1 

1113.4 61.8 22.8 

lh.4 17.3 9.8 

1'38. ,11 12 7. h 34.8 

n11:-:. 7 4611. 8 8 3. s 

1cumulative production and reserves are as of December 31, 1979. Production and reserv" figures weree deerived frum .\PI 

and AGA data (American Petroleum Institute, American Gas Association, and Canadian Petroleum ,\ssuciatinn, 19fill) except fur 

California for which production and reserve data were taken from the California Division ,,f (lil and Gas (19811) and the U.S. 

Geological Survey (Kalil, 1981)). 

~ 

-Does not include gas in storage. 

3Fg 5 denotes the 95th fractile; the probability of mOP2 than the amount F95 is 95 percent. F5 is defined similarly. 

Fractile values are not additive. 

4 Includes quantities considered recoverable onlv if technology permits tlteeir exploitation heenc>ath Arctic pack ice--a 

condition not yet met. 

5Estimates of non-associated and associated-dissolved gas reserves in California Federal offshore areas are not recorded 

separately. All gas in these areas is here treated ,;s associated-dissolved c;as. 

6API and AGA reserve data for the Gulf of clexicu are not available within separat~· shelf and slope classifications. 

However, the declared reserves probably represent only the shelf and are so treated. 

adjusted these estimates for discoveries made in 

1979. API cumulative production, proved 

reserves, and indicated additional reserves as 

24 

of the end of 1979 were subtracted from these 

adjusted estimates to obtain our inferred 

reserves. The inferred reserves were allocated 
Table 7.--Total gas--PPoduction, PesePVes, and estimates of undiscoVePed 

PecovePable PesouPces of the United States 

[All tabulated values are rounded numbers; therefore values for production and reserves and for means of 

undiscovered resources, all of which are additive, may not be precisely so. Values shown are in trillion 

cubic feet. Negl., negligible, less than or equal to 0,05 trillion cubic feet of gas] 

Cumulative Identified resources 1•2 Undiscovered recoverable resources 

Petroleum Region production1 Measured Inferred ~OW ~igh Standard 

reserves reserves F95 F5 Mean deviation 

Onshore 

1 Alaska •••••••••••••••••••••• 1.2 30.0 4.4 19.8 62.3 36.6 14.0 

2 Pacific Coast ••••••••••••••• 27.0 4.2 3.8 8.2 24.9 14.7 5.5 

Colorado Plateau and 

Basin and Range,,,,,,,,,,, 15.0 11.4 4.5 53.5 142.4 90.1 29.7 

4 Rocky Mountains and 

northern Great Plains ••••• 13.2 7.1 5.5 29.6 69.0 45.7 12.6 

5 West Texas and eastern 

New Mexico •••••••••••••••• 70.7 15.9 18.1 22.4 75.2 42.8 17.8 

6 Gulf Coast •••••••••••••••••• 228.5 45.3 74.3 56.5 249.1 124.4 63.6 

7 Mid-continent ••• ,.,,,,.,,,,, 127.8 32.0 18.8 22.9 80.8 44.5 18.4 

8 Michigan Basin •••••••••••.•• 1.3 1.1 1.1 1.8 10.9 5.1 3.1 

9 Eastern Interior •••••••••••• 1.8 Negl. 0.1 1. 2 5.0 2. 7 1.3 

10 Appalachians •••••••••••••••• 34.2 6.2 5.9 6.4 45.8 20.1 13.2 

11 Atlantic Coast •••••••••••••• Negl. Negl. Negl. Negl. 0.4 o. 1 0.3 

Entire onshore •••••••••••••••••• 520.6 153.3 136.5 322.5 567.9 426.8 78.5 

Offshore--shelf 

lA Alaska4 •••••••••••••••••••• 0.6 2.0 1.2 28.5 99.0 57.4 23.6 

2A Pacific Coast •••••••••••••• 1.5 1.9 0.4 0.9 5.2 2.5 1.5 

16A Gulf of Mexico ••••••••••••• 55.3 534.4 539.5 22.0 79.2 45.3 18.5 

llA Atlantic Coast ••••••••••••• 0 0 0 2.2 17.9 8.2 5.0 

Entire shelf •••••••••••••••••••• 57.5 38.2 41.0 72.0 166.8 113.4 30.4 

Offshore--slope 

1A Alaska4 •••••••••••••••••••• 0 0 0 0 20.2 7.2 12.3 

2A Pacific Coast •••••••••••••• 0 0 0 1.9 10.2 4.4 3.0 

6A Gulf of Mexico, •••••••••••• Negl. No data 5 No data5 11.1 51.8 26.5 13.8 

llA Atlantic Coast ••••••••••••• 0 0 0 5. 1 34.5 15.4 9.6 

Entire slope •••••••••••••••••••• 0 0 0 28.6 87.1 53.6 21.0 

Offshore--combined shelf and slope 

1A Alaska4 •••••••••••••••••••• 0.6 2.0 1.2 33.3 109.6 64.6 26.6 

2A Pacific Coast •••••••••••••• 1.5 1.9 0.4 3.7 13.6 6.9 3.3 

6A Gulf of Mexico ••••••••••••• 55.3 34.4 39.5 41.7 114.2 71.8 23.1 

11A Atlantic Coast ••••••••••••• 0 0 0 9.2 42.8 23.7 10.8 

Entire offshore ••••••••••••••••• 57.5 38.2 41.0 117.4 230.6 167.0 37.0 

Combined onshore and offshore 

Entire United States •••••••••••• 578.0 191.5 177.5 474.6 739.3 593.8 86.8 

1cumulative production and reserves are as of December 31, 1979. Production and reserve figures 

were derived from API and AGA data (American Petroleum Institute, American Gas Association, and Canadian 

Petroleum Association, 1980) except for California for which production and reserve data were taken from 

California Division of Oil and Gas (1980) and the U.S. Geological Survey (Kalil, 1980). 

2Does not include gas in storage. 

3F95 denotes the 95th fractile; the probability of mope than the amount F95 is 95 percent. 

F5 is defined similarly. Fractile values are not additive, 

4Includes quantities considered recoverable only if technology permits their exploitation beneath 

Arctic pack ice--a condition not yet met, 

5API and AGA reserve data for the Gulf of Mexico are not available within separate shelf and slop~ 

classifications. However, the declared reserves probably represent only the shelf and are so treated, 

to our Regions. 

Inasmuch as oil and gas data do not allow 

the development of separate growth histories for 

25 

Alaska, the 

conterminous 

Alaska. 

pattern of 

States as 

growth 

a whole 

shown for 

was used 

the 

for 
ESTIMATES OF PETROLEUM RESOURCES 

Results of Study 

Tabulations of cumulative production; 

measured, indicated and inferred reserves; and 

estimates of undiscovered recoverable 

hydrocarbon resources are presented in tables 4 

through 7. Statistics for oil (table 4), 

associated-dissolved gas (table 5), nonassociated gas (table 6), and total natural gas 

(table 7) are presented for each of the 15 

Regions as well as for the onshore area, the 

offshore area, the entire United States, and 

other selected areas. Individual province 

6.9-25.9 

14.2 

EXPLANATION 

OIL, IN BILLION BARRELS 

Fgs-Fs 

2.7-9.4 

MEAN 

5.4 

4.6-24.2 

12.2 

6.Q-14.0 

9.4 

2.5-14.6 

6.9 

estimates of undiscovered resources are provided 

in Appendixes C and D. 

The data for cumulative production, 

measured reserves, and indicated reserves in 

tables 4 through 7 were derived from the API and 

AGA (API and others, 1980) except that 

California reserve statistics were based on data 

from the California Division of Oil and Gas 

(1979) and the U.S. Geological Survey (Kalil, 

1980). In some instances, reserves had to be 

allocated between two or more Regions; where 

done, all divisions were made proportional to 

the 1978 annual production. Inferred reserves 

were calculated from these data by the 

procedures discussed on p. 22 • These reserves 

2.3-7.7 

4.4 

64.3-105.1 

82.6 

ENTIRE UNITED STATES 

INCLUDING ALASKA 

AND OFFSHORE 

Figure 13.--Crude oil--Ranges and means of undiscovered recoverable resource by Region. (See 

fig. 3 for No. and name.) 

26 
and produced 

reference for 

resources. 

quantities provide 

the estimates of 

a frame of 

undiscovered 

The undiscovered recoverable oil of the 

United States is estimated to range from 64.3 to 

105.1 billion barrels with a mean estimate of 

82.6 billion barrels. The undiscovered 

recoverable gas is estimated to range from 474.6 

to 739.3 trillion cubic feet with a mean 

estimate of 593.8 trillion cubic feet. Each 

range corresponds to 95 percent and 5 percent 

probabilities of moPe than the respective 

amounts. 

The geographic distribution of estimated 

undiscovered resources is shown graphically in 

EXPLANATION 

GAS, IN TRILLION CUBIC FEET 

Fgs-Fs 

29.6-69.0 

MEAN 

45.7 

33.3-109.6 

64.6 

29.6-69.0 

45.7 

19.8-62.3 

36.6 

figures 13 and 14 and is further compared as 

percentage distributions in figures 15 and 16. 

Resources are not uniformly distributed; a few 

Regions contain most of the estimated 

undiscovered oil and gas. First, 66 percent of 

the mean estimate for undiscovered oil and 72 

percent for gas is onshore. Almost 90 percent 

of the onshore potential is found in 6 of the 11 

Regions (namely 1 and 3 through 7). Similarly, 

of the offshore Regions, the Gulf of Mexico plus 

Alaska contain 67 percent of the oil potential 

and 82 percent of the gas potential. Analysis 

of the detailed tables of province estimates in 

Appendixes C and D indicates that commonly a few 

individual provinces in each of the Regions (for 

22.9-80.8 

44.5 

474.6-739.3 

593.8 

ENTIRE UNITED STATES 

INCLUDING ALASKA 

AND OFFSHORE 

-~igure 14.--Total natural gas--Ranges and means of undiscovered recoverable resource by Region. 

(See fig. 3 for No. and name.) 

27 
example, the Wyoming-Utah-Idaho overthrust belt 

of Region 3) account for most of the potential 

in those Regions. 

Figures 17 and 18 show regional 

distribution of mean estimates of undiscovered 

recoverable resources, as well as the 

distribution of discovered amounts of oil and 

gas. Most mature areas have amounts of 

undiscovered resources that are approximately 

equal to reserves. Frontier provinces are 

characterized by high undiscovered to discovered 

ratios, as in Regions 3 and 4 and in the 

offshore Regions exclusive of the Gulf of 

Mexico. The relatively low proportion of 

undiscovered to discovered quantities in onshore 

frontier Alaska (Region 1) is controlled by the 

presence of a single giant field, Prudhoe Bay, 

making Alaska appear similar to mature provinces 

in this respect. However, large amounts of oil 

and gas also remain undiscovered in some more 

maturely explored Regions, such as the Gulf 

Coast and the Gulf of Mexico. 

Although it is convenient to use a point 

estimate, such as the mean, as a basis for 

comparison, a range of values (or interval 

estimate) more properly expresses the 

uncertainty inherent in estimates of 

11 A Atlantic Coast 

6A Gulf of Mexico 

1AAiaska 

11 Atlantic Coast 

<::1% 

10 Appalachians 1°/o 

9 Eastern Interior 

1% 

8 Michigan Basin 

1% 

6GulfCoast 

undiscovered resources. Point estimates may 

convey an impression of exactness that is highly 

misleading. Aggregate probability distributions 

for undiscovered recoverable oil and gas for the 

United States are presented in figures 19 and 

20, and show the amounts of resources and the 

respective probabilities of moPe than those 

amounts. 

Although the oil ranges from 64.3 billion 

barrels (the 95th fractile) to 105.1 billion 

barrels (the 5th fractile), and gas ranges from 

474.6 trillion cubic ft to 739.3 trillion cubic 

ft; lower or higher amounts (fractiles) may be 

read directly from the curves. Appendix A 

contains the aggregate probability distributions. 

Table 8 presents mean estimates of 

undiscovered recoverable resources of NGL in the 

United States. These amounts were calculated by 

the procedures explained on p. 22 • Natural gas 

liquids are a significant component of the total 

liquid hydrocarbons. They add approximately 

17.7 billion barrels, on a mean estimate basis, 

to the assessed crude oil estimate of 82.6 

billion barrels, and constitute approximately 18 

percent of total liquids. 

2 Pacific Coast 

11% 

/ 

17% 3 Colorado Plateau and 

Basin and Range 

4 Rocky Mountains and 

Northern Great Plains 

5WestTexasand 

Eastern ~Jew Mexico 

EXPLANATION 

D Onshore 

f•' I Offshore 

Figure 15. --Crude oil--Undiscovered recoverable resource by Region as percentage 

of the total estimate for the United States, based on mean estimates. 

28 
Comparison of Recent Hydrocarbon 

Resource Estimates 

Many estimates of United States recoverable 

oil and gas resources have been published since 

1909, and have been compared by McCulloh (1973), 

Miller and others (197 5), Sheldon (197 6), 

Potential Gas Committee (1977a), and Masters 

(1979). Selected estimates appearing since 1970 

are reviewed here (figs. 21 and 22). Direct 

comparison among these estimates is difficult 

for the following resasons: 

1. Inclusion or exclusion of important areas, 

such as Alaska; 

2. Differences in offshore areas as defined by 

different wa ter depths; 

3. Inclusion or exclusion of natural gas 

liquids in the estimates of crude oil; 

4. Inclusion or exclusion of inferred reserves; 

5. Assessment of quantities other than 

recoverable quantities; and 

6. Differences in type of reported statistic 

(mean, mode, range, "expected value", 

etc,), or that the type of statistic is 

not explained . 

11AAtlanticCoast 

6AGulfofMexico 

11 Atlantic Coast onshore < 1% 

9 Eastern Interior < 1% 

8 Michigan Basin 

1% 

7 Mid-continent 

Prior to 1975, there we r e several estimates 

that had values greater than 200 billion barrels 

of oil. Since 1975, however, as shown in figure 

21, there has been a gene ral consensus 

concerning the order of magnitude of 

undiscovered resources. Interval estimates 

generally overlap, and, excluding Nehring's 

(1981) estimates, the point estimates range from 

55 to 113 billion barrels. 

An examination of natural gas estimates 

(fig. 22) suggests a similar tendency toward 

consensus. The interval estimates published 

since 1975 also generally overlap; the point 

estimates, exclusive of Nehring (1981), range 

from 287 to 820 trillion cubic feet. 

Some significant differences exist between 

the estimates presented in our report and those 

published by the USGS in 1975 (Miller and 

others). These differences essentially reflect 

the results of new data and new concepts. For 

example, results of exploratory drilling in some 

relatively unexplored areas, particularly the 

Gulf of Alaska, southern California borderland, 

and south Atlantic shelf have been 

disappointing, and geologic information obtained 

from those provinces indicates reduced 

15% 

8% 

3 Colorado Plateau and 

Basin and Range 

4 Rocky Mountains and 

Northern Great Plains 

5WestTexasand 

Eastern New Mexico 

21% 

6 Gulf Coast 

EXPLANATION 

D Onshore 

I .•.•. i. il Offshore 

Figure 16.--Natural gas--Und iscovered recoverable resource by Region as percentage of the total 

estimate for the United States, based on mean estimates. 

29 
40 

ONSHORE OFFSHORE 

(/) 30 "0 

w c u "' a: ::JQ) 

::J "'O> 

0 !c "0 "' "'"' c c (/) a: a: m ·ro w 

a: o" .~ ~ 0 "OC 0 w 20 "'"' ~ c c "'"' ("u a: .2 ·c;; "' ::J(.? ·;;: """ 0 w oro 0 c -o"' "' u 

> ucn c::;;: "' ·;;: 0 ::;;:~ ~ <( Q) 

u "" >"' "' ;:: "' c 'ii) ::;;: 'ii) _,..<: l(lQ) "' Q) <t (/) "' ut xz 0 c "' 0 0 0 0 0 u c 0 

z u a:z "'c ~ ·~ ·u; 0 "' ~ u ~ 1-~ "' ·~ c ::J 10 u '<t ~Q) ::J "' 0 ~ "'~ (.? "' "' u en 0 ·;::; Q)<ll -6 c E .<: u ~~ "' u 

"' ~ "' " a._ Ol Iii . ., :.c c. c ~ c. "' <t ~ 

0 

z 10 0 

f= 

u 

::J 

0 

0 

a: 

a._ 

w 20 > 

f= 

<t 

_J 

::J 

::;;: EXPLANATION ::J 

u 

0 D 30 Undiscovered recoverable 

z resource (mean estimate) <t 

(/) Inferred reserves w 

> a: Demonstrated reserves w 

(/) 

w 40 Cumulative production a: 

50 ~---------------------------------------------------------L------------------~ 

Figure 17.--Crude oi l--Es timates of discovered amounts (cumulative production and reserves) and 

undiscovered amounts (mean estimates) in billion barrels by Reg ion. 

30 
200 

"tJ ONSHORE OFFSHORE 

c tl "' :::J ., (/) "' "'rn 0 

L1J ! c u u 150 "'"' :!::: a: 0 a: a: "O Vl :::J (.) :J o"O c c (.:J ·x 0 ro· rn 0 .., "tJ c .~ ., (/) "' "' .~~ :2: L1J ~ c a: _9 ·u; "' "' ..... 0"' _., c 0 a 100 U<Il c ~ ., :!::: L1J :::J(,:J :::J a: (") 0 c c (.:J L1J :2:~ ~ Vl 

> <!: ., 0 c > .<: .~ .., 0 tl tt (.) c . u ., ·v; 0 .<: tl -

Vl 

"' o o "' ·~ (.) "' (/) 0 a:z ~ "' "' 0 15 al 0 

50 u ... c c "' u u z (.) 

"' c. :J ;;::: .~ c. ' i) <!: "' .<: 0.. .~ 

:2: 

0 

50 

z 

0 

i= 100 u 

:J 

a 

0 

a: 

0.. 

L1J 

> 150 i= 

<!: 

....J 

:J 

:2: 

:J 

u 

a 200 EXPLANATION 

<!: 

z D Undiscovered recoverable (/) resource (mean estimate) L1J 

> Inferred reserves a: 

L1J 250 (/) 

L1J Demonstrated reserves a: 

Cumu lative production 

300 

350 L_------------------------~~----------------------------J-------------------~ 

Fi gur e 18 . --Na tura l gas--Es t ima t es of discovered 

a nd und iscovered recove r able amo un ts 

Region. 

31 

amounts (cumulative pr oduction and r eserves) 

(mean est ima t es) in trillion cubic feet by 
0 . 

z 

CI:CD 

I 

f--oO . 

w 

0::: 

Oco 

l::ci 

t.... 

a 

>-- ... f--o • ....... o 

__] 

........ 

£D 

CI:N 

£D • Do 

0::: 

a... 

0 . 

0 

0.0 20.0 

1\ ESTIMATES 

ME: AN - 82.59 

MEDIAN - 81.23 \ 95% - 64.29 

75% - 73.59 

SO% - 81.23 

25% - 89.81 

\ 5% - 105.10 

MODE: - 79.96 

\ S.D . - 13.45 

\ ~ 

40.o so.o eo. o 100.0 120.0 t4o.o 1so.o 1eo.o 200.0 

BILLION BARRELS RECOVERABLE OIL 

Fi gur e 19. - - Crude oil--Probabil i t y distribu tion of t he undiscovered recoverable r esour ces fo r 

0 

z 

CI:m I. 

f-oC 

w 

0::: 

Dco l:: . 

0 

>--.,. 

f-o . ....... o _J 

-

£D cr:::N 

£D • oo 

0::: 

a... 0 

ci 

0.0 

the United St a t es . Estima t es are mean , median , mode, s ta nd ard deviation (S.D . ) , 

and fractiles t hat correspond to the percent ages list ed . 

95.0 

........_, 

~ ESTIMATES 

ME: AN - 593.80 

\ MEDIAN - 582.27 

95/. - 474.57 

75% - 535.04 

50/. - 582.27 

25/. - 639.75 \ 5/. - 739.31 

MODE - 577.56 

\ 5. D. - 86.75 

~ ,..__ 

190.0 285.0 380.0 175.0 570.0 665.0 760.0 855.0 950.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

Fi gure 20 .--Natural gas- -Probability dist ribution of the undiscove r ed recove r able r esour ces for 

the Uni ted States. Es t imates a r e mean, median, mode , s t andard devia t ion (S . D. ) , 

and f r actil es tha t correspond to t he percentages listed . 

32 
500 ,-------------------------------------------------------------------------------~ 

U) 

...J 

w 

400 

~ 300 <( 

aJ 

z 

0 

:::i 

...J 

iii 

~ 

...J 

0 

w § 200 

a: 

u 

100 

0 

0 

0 I 

EXPLANATION 

0 Point estimate 

I High estimate 

Average estimate 

Low estimate 

I 

0 L---------------------------------------------------------------------------------~ 

Cil 

Qi N.C. 

....... 0 

"'-c c: 

U)~ (!)Iii 

Ul.o 

:::J 0 

Q) 

..r:. 

!:: 

11ncludes natural gas liq~ids 

t 

Q) '¢ 

.Or-. 

.om 

::::l 

::c 

..r:. 

u 

~ Q) ~ 

:fl ~It) a: c: S; Iii ::::l c: 0 0 u ... 

«< 

z 

z c.o Or-. 

X m X 

w 

Cl 

.§ 00 ..r:.m 

Q) 

z 

Figure 21.--Crude oil--Selected estimates of undiscovered recoverable resources for the 

United States. 

33 
2500 ,----------------------------------------------------------------------------------, 

EXPLANATION 

0 0 Point estimate 

2000 High estimate I Average estimate 

Low estimate 

Iw 

w 

u.. 

u 1500 ii5 

:::> 

u 

z 

0 

::::i 

...J 

a: 

I-

~ 

u) 

<( 

(.!) 

...J 1000 <( 

a: 0 :::> 

I- 0 <( 

z 0 

0 

0 

500 I I 0 0 I I 0 

0 Q) en Q) (/.)~ t Q) Q) ..c ~ z Q) 

(ij Q) Q) Cl Q) .-t a; Q) (.!),.... Q)~ Q) Q) (.) 0 (0 Q) Q) Q) c:.- :t:: :t:: .c,.... :t:: :::::: "'-Ln l.l)Q) ....... :t:: E :t:: :t:: ·;: 00 .E ..c .E CJ)C1l .CC1l .E .E co,... ,......c X ~8. ~ .E .E .E ..CC1l 

~0 :::>.- ::J.- :gC1l C1lo X OO::J Q).- (/.)~ E E ;:tE ::ee Q)\'"" w E ..... o E E z (1)"0 ::c a::= .-"0 (1)-, <.!:J.~ 0 ..... c: 0 

~8<0 ~8<0 -U C/.)c: o.c \'""(/) 0 0 C/.)..C u.- co UM co c: (.!)co u,.... -CO UC1l u.- (/) ....... C/.)"0 (/) ....... =>!::: == ::l~ :t:: ::l~ c: ::J (/.)"'- (/) ....... Qi(.!) (/) ....... !1)00 COC1l (.!)- coC1l oo :::>~ C0(1) ..C-o coC1l coC1l (.!).- (/.)co (.!).- .g~~ ~~~ ·~u (.!).- C/.)c: (.!).- (.!).-

(ij :::>.g ~ ~.!!! ~.!!! z ~ (ij co (ij (ij ·.;:::; Q) ·.;:::; ·.;:::; ·.;:::; c: ..c c: c: c c: Q c: c: 

! !::: Q) Q) Q) Q) Q) Q) 

0 0 0 0 0 0 0 a.. a.. ~ ~ a.. a.. a.. 

Figure 22.--Natural gas--Selected estimates of undiscovered recoverable resources for the United 

States. Estimate for the Potential Gas Committee is their "possible" plus their 

"speculative" estimates. 

34 
hydrocarbon potential. Drilling since 1975 in 

the Cordilleran overthrust belt of the western 

United States (Regions 3 and 4), on the other 

hand, has indicated a large potential for both 

oil and gas in this area, and also has changed 

the concept of the potential of other thrust 

belts. In addition, note that the continental 

slope is included in the area of the current 

assessment, but was excluded from the 1975 

study. 

CONCLUSIONS 

The purpose of this study was to estimate 

the quantities of conventional oil and natural 

gas that may be available for discovery and 

recovery. No attempt was made to predict what 

part of the assessed quantities will be 

discovered or when. Because of uncertainties 

involved in resource estimation, estimates are 

reported as a range of values. The low value 

corresponds to a 95 percent probability of moPe 

than that amount (95th fractile, F95 ) and the 

high value corresponds to a 5 percent 

probability of moPe than that amount (5th 

fractile, F5 ). 

The current appraisal gives a mean estimate 

of undiscovered recoverable crude oil in the 

United States as 82.6 billion barrels and a 

range from 64.3 to 105.1 billion barrels, 

corresponding to the 95th and 5th fractile, 

respectively. The corresponding values for gas 

are a mean estimate of 593.8 trillion cubic feet 

and a range from 474.6 to 739.3 trillion cubic 

feet. The mean value for undiscovered oil is 

about 47 percent of the total oil discovered to 

date and the mean value for gas is about 63 

percent of the total gas discovered to date. 

About 66 percent of the undiscovered oil and 72 

percent of the undiscovered gas is estimated to 

occur onshore. The Region with the greatest 

onshore oil potential is the Colorado Plateau 

and Basin and Range, which includes the WyomingUtah-Idaho thrust belt. Offshore oil potential 

35 

Table 8.--NatuPal gas liquids (NGLJ--Mean esti~tes of 

undiscovePed PecoVePable PesouPces in the United States 

[All tabulated values are rounded from original numbers and 

may not be precisely additive. Values shown are in billions 

of barrels. Negl., negligible, less than or equal to 0.05 

billion barrels of NGL (natural gas liquids)] 

Petroleum Region 

Onshore 

Undiscovered 

recoverable 

NGL 

1 Alaska........................................ 1.3 

2 Pacific Coast................................. 0. 3 

3 Colorado Plateau and Basin and Range 1 . 1

}.. 4 

4 Rocky Mountains and northern Great Pla1ns .O 

5 West Texas and eastern New Mexico............. 1.5 

6 Gulf Coast.................................... 4.0 

7 Mid-continent................................. 1.3 

8 Michigan Basin................................ 0.1 

9 Eastern Interior.............................. 0.1 

10 Appalachians.................................. 0.2 

11 Atlantic Coast •••••••••••••••••••••••••••••••• Negl. 

Entire onshore United States •••••••••••••••••••••• 12.9 

Offshore--shelf and slope 

1A Alaska2 •••••••••••••••••••••••••••••••••••••• 2.1 

2A Pacific Coast •••••••••••••••••••••••••••••••• 0.2 

6A Gulf of Mexico............................... 1.6 

11A Atlantic Coast ••••••••••••••••••••••••• •••••• 0.8 

Entire offshore United States..................... 4.7 

Onshore and offshore 

Entire United States •••••••••••••••••••••••••••••• 17.7 

1Regions 3 and 4 combined because of data availability. 

2rncludes quantities considered recoverable only if 

technology permits their exploitation beneath Arctic pack 

ice--a condition not yet met. 

is greatest for Alaska, followed by the Gulf of 

Mexico and the Atlantic Coast. For gas, the 

mean values indicate that the Gulf Coast has the 

greatest potential onshore and that the Gulf of 

Mexico has the greatest potential offshore. 
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APPENDIX A 

Graphs of aggregate probability distributions for oil, associated-dissolved 

gas, non-associated gas, and total gas for Regions in the United States 

Appendix A 

Aggregate probability distributions 

Graphs showing the aggregate distributions are arranged as listed in the 

index below. Each illustration includes the distributions for oil, 

associated-dissolved gas, non-associated gas, and total gas for the area 

named. Estimates are the mean, median, mode, standard deviation (S.D.), and 

the fractiles that correspond to the percentages listed. 

Page 

Onshore Regions 

1 Alaska. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 44 

2 Pacific Coast................................................... 45 

3 Colorado Plateau and Basin and Range •••••••••••••••••••••••••••• 46 

4 Rocky Mountains and Northern Great Plains....................... 47 

5 West Texas and Eastern New Mexico............................... 48 

6 Gulf Coast • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 4 9 

7 Mid-continent................................................... 50 

8 Michigan Basin.................................................. 51 

9 Eastern Interior................................................ 52 

10 Appalachians.................................................... 53 

11 Atlantic Coast. ••••••••••••••••••• •••••••••••••••••••••••••••••• 54 

Offshore Regions 

lA Alaska: 

Shelf ••••• •••••••••••••••••••••••••••••••••••••••••••••••••••••• 55 

Slope. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 56 

Entire offshore................................................. 57 

2A Pacific Coast: 

Shelf •••••••••••••• •••••••••••••••••••• •••••••••••••• ••••••••••• 58 

Slope........................................................... 59 

Entire offshore ••••••••••••••••••••••••••••••••••••••••••••••••• 60 

6A Gulf of Mexico: 

Shelf........................................................... 61 

Slope........................................................... 62 

Entire offshore................................................. 63 

llA Atlantic Coast: 

Shelf........................................................... 64 

Slope........................................................... 65 

Entire offshore •••••••••••••••••••••• ~.......................... 66 

Entire onshore............................................................ 67 

Entire shelf.............................................................. 68 

Entire slope•••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 69 

Entire offshore••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 70 

Entire United States•••••••••••••••••••••••••••••••••••••••••••••••••••••• 71 

43 
t 

OIL 

a 

z a:Q) 

I. 

f--<0 

w 

cr 

Ow 

Eci 

L... 

0 

>-o..-

!::a 

_J 

(D 

a:"' (D • 

oa 

cr 

CL 

a 

ci 

\ 

\ 

0.0 3.5 

ESTIMATES 

MEAN = 6.87 

MEDIAN - 5.86 

95% = 2.53 

75% = 1.09 

50% - 5.86 

\ 25% = 8.42 

5% = 14.59 

MODE - 5.07 

5.0. = 4.27 

~ "'-, 

~ 

--- - ~-

7.0 10.5 11.0 17.5 21.0 21.5 28.0 31.5. 35.0 

BILLION BARRELS RECOVERABLE OIL 

ASSOCIATED-DISSOLVED GAS 

0 

z 

a: CD I. 

f--<0 

w 

cr 

Ow 

Eci 

L... 

0 

>-- ... !:a 

_J 

(D a:N 

~ci 

cr 

a... 0 

ci 

\ ESTIMATES 

MEAN = 15.83 

MEDIAN - 13.03 \ 95% = 5.29 

75% = 8.88 

50% - 13.03 

\ 25% = 19.59 

5% = 36.45 

MODE - 10.57 

\ S.D. = !0.87 

I 

~ r--- -- '-

0.0 10.0 20.0 30.0 iO.O 50.0 60.0 70.0 80.0 90.0 100.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

TOTAL GAS 

0 

z 

a: CD I. 

f--<0 

w 

cr 

OUJ 

E • 0 

L... 

0 

>-- .... !::ci 

_J 

(D a:N 

~ci 

cr 

a... 0 

ci 

i\ ESTIMATES 

MEAN = 36.57 

MEDIAN - 34.05 \ 95% = 19.77 

75% = 27. 11 

50% - 34.05 

1\ 25% = 43.14 

5% = 62.'30 

MODE - 29.41 

\ S.D. = 14.05 

~ 

----- -

0.0 i5.0 30.0 15.0 60.0 75.0 90.0 105.0 120.0 135.0 150.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

0 

z 

a: CD I. 

f--<0 

w 

cr 

OUJ 

E' 0 

L... 

0 

>-- ... !:a 

_J 

~~ a:lo 0 

cr 

a... 0 

ci 

\ I ESTIMATES 

MEAN = 20.74 1 MEDIAN- 19.06 

~ 95% = 10.05 

75% = 14.46 

50% - 19.06 

\ i 25% = 24.88 

5% = 36.98 

MODE - 14.34 

1\ S.D. = 8.91 

"~ r---- -

0.0 7.0 14.0 21.0 28.0 35.0 12.0 i9.0 56.0 63.0 70.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

Region I.--Alaska 
.p.. 

ln 

OIL 

a 

z 

a:., 

:c . I-' a 

w 

a:: 

010 

~d 

L... 

0 

>--~ 

!:;a 

_J 

~~ a:la 

0 

a:: 

a.. a 

d 

1\ ESTIMATES 

MEAN - 4.35 

MEDIAN - 3.97 \ 95% - 2.10 

\ 75% - 3.03 

SOY. - 3.97 

\ 25% - 5.17 

5% - 7.89 

MODE - 3.21 

\ S.D. - 1.95 

~ "'-. 

1'---

0.0 1.8 

--

1.2 

-

i.B 6.i 8.0 -- 9.6 ll.2 12.8 1i.1 16.0 

BILLION BARRELS RECOVERABLE OIL 

ASSOCIATED-DISSOLVED GAS 

a 

z 

a:., 

:c . ...... Cl 

w 

a:: 

olD 

~. 

L... 

0 

a 

>--~ ...... . .....,a 

__] 

(I) 

a:N 

(I) • 

oa 

a:: 

a.. a 

d 

1\ ESTIMATES 

MEAN - 5.01 

\ MEDIAN - 4.16 

95% - 2.32 

75% - 3.39 

50% - 4.46 

[\ 25% - 5.91 

5% - 9.34 

MODE - 3.76 

\ S.D. - 2.43 

" 

~ 1----t--

0.0 2.0 1.0 6.0 8.0 10.0 12.0 li.O 16.0 18.0 ZJ.O 

TRILLION CUBIC FEET RECOVERABLE GAS 

TOTAL GAS 

a 

z 

a:., 

.:c . f-oCI 

w 

a:: 

olD 

::c • 

L... 

0 

a 

>--~ ...... . .....,a 

__] 

co a:N co • oa 

a:: 

a.. a 

d 

\ ESTIMATES 

MEAN - 14.66 

\ MEDIAN - 13.48 

95% - 8.21 

75% - 10.90 

50% - 13.48 

1\ 25% - 16.88 

5% - 24.92 

MODE - 11.57 

\ S.D. - 5.51 

~ t---

0.0 &_.0 12.0 18.0 21.0 30.0 36.0 12.0 i8.0 Si.O 60.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

a 

z 

a:., 

.:c. 

...... Cl 

w 

a:: 

olD 

~. 

L... 

0 

a 

>--~ !::a 

__] 

co a:N co • oa 

a:: 

a.. a 

d 

1\ ESTIMATES 

MEAN - 9.64 

\ MEDIAN - 8.48 

95% - 4.39 

75% - 6.39 

50% - 8.48 

25% - 11.54 

~ 5% - 19.46 

MODE - 6.19 

\ S.D • - 4.94 

~ 

--- 1'---- L____ 

0.0 i.O 8.0 12.0 16.0 20.0 21.0 28.0 32.0 36.0 40.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

Region 2.--Pacific Coast 
OIL 

a 

z 

a: .:rC 

l--<ci 

w 

0:: 

i?~ L...a 

C) 

i:"': ,_a 

_J 

CD 

O:N 

CD • a a 0:: 

a... a 

ci 

"" ESTIMATES \ MEAN - 14.16 

\ HtDIAN - 12.58 95~ - 6.89 

75Y. - 9.74 

SOY. - 12.58 

\ 25~ - 16.31 

SY. - 25.91 

MOOE: - 11.01 

t\ S.D. - 7.96 

~ 

'--

o.o 7.0 14.0 21.0 28.0 35.0 42.0 49.0 56.0 &3.0 70.0 

BILLION BARRELS RECOVERABLE OIL 

~ ASSOCIATED-DISSOLVED GAS 

a 

z 

a:c .:r. 

l--<0 

w 

0:: 

Oca l:. 

L... 

C) 

a 

i:"': ,_a 

_J 

...... 

CD 

O:N 

CD • a a 0:: 

a... a 

d 

' EST I MATES 'I \ MCAN - 28. 47 

\ 

ME:OI AN • 25. 90 95~ - 11.10 

75% - 20.20 

SO% - 25.901 \ 25% - 33.86 

5% - 51.08. 

MODE - 25.68 1 

S.D. - 13.90 

\ 

"' -

I'--

0.0 lS.O 30.0 45.0 60.0 75.0 90.0 105.0 140.0 JJS.O 150.0 

TRILLION CUBIC FEET RECOVERABLE GAS· 

TOTAL GAS 

a 

z 

a:c .:r. 

(--<a 

w 

0:: 

Oca 2: • 

a L... 

C) 

>-- .. ....... 

,_a 

_J 

CD 

O:N 

CD • a a 0:: 

a... a 

d 

\ ESTIMATES 

ME: AN - 90.07 

\ MEDIAN • 85.23 95~ - 53.49 

75% - 70.22 

\ 50% - 85.23 

\ 25% - 101.33 

51. - 112.40 

MODE - 72.08 

\ S.D. - 29.74 

"' "" c________ I'--- .~ 

o.o 25.0 50.0 75.0 100.0 125.0 150.0 175.0 400.0 225.0 250.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

a 

z 

a:c .:r. 

l--<o 

w 

0:: 

Oca 2:. a L... 

C) 

i:"': ,_a 

_J 

...... 

CD 

O:N 

CD • a a 0:: 

a... a 

d 

\ ESTIMATES I 

ME: AN - 61.60 

\ ME:Diff-4 - 56.72 

95/. - 30.191 

751. - 43.41 

SO% - 56.72 

\ 25~ - 73.41 

51. - Ill. 10 

r\ MOOC - 51.64 

\_ S.D. - 26.30 

~ r---..... 0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0 400.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

Region 3.--Colorado Plateau and Basin and Range 
OIL 

0 

z 

CCCD I. 

f-< ,CJ 

w 

0::: 

0(0 

:t:ci 

~ 

>-- .... t;ci 

..J 

(D 

CCN 

(D • 

ao 

0::: 

Cl.. 

0 

d ~ ' ~ ~ 

0.0 2.5 

1\ ESTIMATES 

MEAN - 9.38 

MEDIAN - 9.02 

\ 95/. - 5.98 

75% - 7.59 

50/. - 9.02 

\ 25/. - 10.65 

5% - 13.95 

MODE - 8.01 

\ S.D. - 2.60 

1\ 

""' "----

5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 

BILLION BARRELS RECOVERABLE OIL 

~ ASSOCIATED-DISSOLVED GAS 

0 

z 

(CCD 

I. 

f--<0 

w 

0::: 

Om 

:E:c:i 

4.. 

Cl 

>-- .... t;a 

....J 

(D 

(CN 

(D • 

00 

0::: 

Cl.. 

0 

0 

0.0 3.0 

1\ ESTIMATES 

ME: AN - 11.21 

MEDIAN - 10.70 \ 95/. - 6.68 

~ 75Y. - 8.78 

50% - 10.70 

~ 25/. - 13.00 

5% - 17.33 

MODE - 9.23 

' S.D. - 3.54 

.~ 

"' ~ - ~~--

6.0 9.0 12.0 15.0 18.0 21.0 2-t.O 27.0 30.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

TOTAL GAS 

0 

z 

CCCD .:c . f--<0 

w 

0::: 

ClfO x:ci 

4.. 

Cl 

>-- .... t;a 

..J 

a:lo 

~~ 

Cl 

0::: 

Cl.. 

0 

d 

""""' ESTIMATES 1\ MEAN - 45.67 

MEDIAN - 43.50 

\ 95/. - 29.62 

75% - 36.84 

50% - 43.50 

\ 25/. - 51.86 

5% - 68.99 

MODE - 38. 16 

\ S.D. - 12.64 

_j 

" I 

"---~ - l ___ __j 

o.o 15.0 30.0 45.0 60.0 75.0 90.0 105.0 120.0 135.0 150.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

0 

z 

(CCD 

.:c . f-<CJ 

w 

0::: 

ClfO 

:t:d 

4.. 

Cl 

>-- .... t;ci 

..J 

....... 

(D 

(CN 

(D • 

00 

0::: 

Cl.. 0 

d 

........... 

ESTIMATES 1\ MEAN - 34.47 

MEDIAN - 32.02 \ 95/. "' 19.83 

75Y. - 26.09 

50% - 32.02 

1\ 25/. .. 39.87 

5% - 56.18 

MODE - 30.81 

\ S.D. - 12. 14 

!"... 

~ 

- -

:----- o.~o 10.0 20.0 30.o -to.o 5o.o so.o 1o.o eo.o 9o.o 100.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

Region 4.-Rocky Mountains and Northern Great Plains 
OIL 

0 

z 

CI:CD :::c . .....,o 

w 

a:: 

oro 

:l:d 

t... 

0 

>-< ... t:ci 

_] 

(D 

<CN 

(D • 

Do 

a:: 

a.. 0 

d 

\ ESTIMATES 

ME: AN - 5.40 

\ MEDIAN - 5.00 

95% - 2.70 

75% - 3.84 

50% - 5.00 

\ 25% - 6.46 

5% - 9.41 

MODE - 4.72 

\ S.D. - 2.23 

~ r--- - ~ 

o.o 1.8 3.6 5.i 7.2 9.0 10.8 12.6 1'1.'1 16.2 18.0 

BILLION BARRELS RECOVERABLE OIL 

~ ASSOCIATED-DISSOLVED GAS 

0 

z 

CI:CD 

:co 

...... 

w 

a:: 

oro 

:l:c) 

L.... 

0 

>-< ... t:a 

_] 

(D 

(CN 

(D • 

Do 

a:: 

a.. 'o 

d 

~ ESTIMATES 

ME: AN - 10.01 

MEDIAN - 9.18 

'I\ 95% - 4.78 

75% - 6.981 

50% - 9.18 

\ 25% - 12.14 

5% - 18.04 

MODE - 8.92 

~ S.D. - 4.22 

I 

"~ I 

1--- --

0.0 3.5 7.0 10.5 11.0 17.5 21.0 21.5 28.0 31.5 35.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

TOTAL GAS 

0 

z 

~«! f-oCI 

w 

a::: 

Dw 

~. 

L... 

0 

0 

>-<.,.. 

....... 

,_a 

_] 

(D 

<CN 

(D • 

Do 

a::: 

a.. 0 

d 

\ ESTIMATES 

MEAN = 42.77 

MEO[RN - 38.61 

\ 95% = 22.42 

75% = 30.77 

50% - 38.61 

\ 25% = 50.41 

5% = 75.24 

MODE - 34.06 

S.D. = 17.78 

I~ ', 

I'~ t-- I 

0.0 15.0 30.0 45.0 60.0 75.0 90.0 105.0 120.0 135.0 150.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

0 

z 

CI:CD 

:::c . .....,o 

w 

a::: 

Oco 

~d 

L.... 

0 

>-< ... 

t:a 

_] 

...... 

(D 

(CN 

(D • 

Do 

a::: 

a.. 0 

d 

\ ESTIMATES 1\ ME: AN = 32.75 

MEDIAN - 28.82 \ 95% - 13.89 

75% = 21.29 

50% - 28.82 

\ 25% - 39.90 

5% - 67.31 

1\ MODE - 22.82 

\ S.D. - 17.27 

~ r---- --

0.0 15.0 30.0 15.0 60.0 75.0 90.0 105.0 120.0 :35.0 150.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

Region 5.-West Texas and Eastern New Mexico 
OIL 

CJ 

z 

~CD 

:r. 

f--<0 

\ ESTIMATES 

ME: AN - 7.12 

MEDIAN - 6.67 

w 

Q::: 

Occ 

:::c • 

L... 

0 

CJ 

>-..,. E-< • ,....o 

_.J 

CD 

~N 

CD • ao 

Q::: 

c.. 

CJ 

d 

0.0 2.5 

\ 95% - 3.65 

75% = 5.21 

50% - 6.67 

\ 25% - 8.67 

5% - 12.57 

MODE - 5.64 

~ S.D. .. 2.82 

"~ -- L_ 

5.0 7.5 10.0 12.5 l5.0 17.5 20.0 22.5 25.0 

BILLION BARRELS RECOVERABLE OIL 

~ 

~ ASSOCIATED-DISSOLVED GAS 

CJ 

z 

~CD 

:r . E--<0 

w 

Q::: 

OlD 

:::Cci 

L... 

0 

>- .... E-<ci 

_.J 

~"! CDc 

0 

Q::: 

a.. CJ 

d 

1\ ESTIMATES 

ME: AN - 11.78 

\ MEDIAN - 10.37 

95% - 5.22 

75% - 7.73 

50% - 10.37 

1\ 25% - 14.25 

5% - 22.53 

MODE - 8.92 

\ S.D. ... 5.89 

~ 

""' !'--. t---

0.0 i.5 9.0 13.5 18.0 22.5 27.0 31.5 36.0 iO.S ¥.).0 

TRILLION CUBIC FEET RECOVERABLE GAS 

TOTAL GAS 

CJ 

:z 

~CD 

:r . E--<0 

w 

Q::: 

OCD 

l:cj 

L... 

0 

>- .... 

~d 

....J 

CD 

~N 

CDci 

0 

Q::: 

a.. CJ 

d 

' 1\ ESTIMATES 

ME: AN - 124.41 

\ MEDIAN - 109.71 

95% .. 56.48 

75% = 82.68 

50% - 109.71 

\ 25% - 150.00 

5% - 249.06 

\ MODE - 91.48 

\ S.D. "' 63.62 

~ 1---- I '---

0.0 55.0 110.0 165.0 220.0 275.0 330.0 385.0 HO.O i95.D 550.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

CJ 

:z 

~CD 

:r . E--<0 

w 

Q::: 

OCD 

l:cj 

L... 

0 

>- .... 

~d 

....J 

CD 

~N 

CDci 

0 

Q::: 

a.. CJ 

d 

........., 

ESTIMATES I 1\ ME:AN - 112.63 

\ MEDIAN- 95.721 

95% - 45.67 

75% - 69.76i 

50% - 95.72 

25% - 135.841 1\ 5% - 228.31 

MODE - 87.27 

\ S.D. - 63.34 

~ 

~ .....____ r-- - '-------

0.0 iS.O 90.0 135.0 180.0 225.0 270.0 315.0 360.0 '\05.0 iSO.O 

TRILLION CUBIC FEET RECOVERABLE GAS 

Region 6.-Gulf Coast 
OIL 

0 

z 

a:: CD ::r: . f-oe 

w 

lr 

Oco 

L:• 0 

~ 

0 

>- ... f-o • _a 

..J 

ID -

a::N 

ID • oo 

lr 

ll.. 

0 

d 

0.0 1.i 

\ ESTIMATES 

MEAN - 4.37 1\ MEDIAN - -4.06 \ 95% - 2.31 

75% '"' 3. 18 

SO% - -4.06 

\ 25% - 5.25 

5% - 7.68 

\ MODE - 3.37 

\_ S.D. - 1. 77 

~ !----

2.8 i.2 5.6 7.0 8.i 9.8 11.2 l2.6 1i.O 

BILLION BARRELS RECOVERABLE OIL 

~ ASSOCIATED-DISSOLVED GAS 

0 

z 

a:: CD ::r:· f-oe 

w 

lr 

oco 

L:d 

~ 

0 

>- .... t:d 

..J 

ID a::N 

ID' oc 

lr 

ll.. 0 

.d 

\ ESTIMATES I 

MEAN - 8.83 

MEDIAN - 8.041 

\ 95% - 4.22 

75% - 6.09 

SO% - 8.04 

\ 25% - 10.66 

5% - 16.371 

MODE - 6.26 

~ S.D. - 4.00 

I 

""-r---.__ 

o.o 3.0 6.0 9.0 12.0 15.0 18.0 21.0 2i.O 27.0 30.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

TOTAL GAS 

0 

z 

a:: CD ::r: . f-oe 

w 

lr 

oco 

rd 

~ 

0 

>- .... t:a 

..J 

ID a::N 

~ci 

lr 

ll.. c 

d 

r\ ESTIMATES 

MEAN .. 44.51 

MEDIAN - 40.88 \ 95% - 22.91 

75% - 31.83 

SO% - 40.88 

' 25% - 52.73 

~ 5% - 80.77 

MODE - 3-4.40 

\ S.D. - 18.39 

~ -- I 

0.0 20.0 iO.O 60.0 80.0 100.0 120.0 liO.O 160.0 18C.O 200.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

c 

z 

a:: CD ::r: . f-oe 

w 

lr 

oco 

rci 

~ 

0 

>- .... t:a 

..J 

..... 

!D a::N 

ID • oo 

lr 

ll.. 

0 

ci 

......, 

1\ ESTIMATES 

MEAN - 35.68 

~ MEDIAN - 31.61 

95% - 15.84 

75% - 23.46 

SO% - 31.61 

' 25% - 44.08 

f\ 5% .. 68.87 

MODE - 21.54 

\ S.D. = 17.95 

"' ...___I'- '--- -

0.0 15.0 30.0 iS.O 60.0 75.0 90.0 105.0 120.0 135.0 150.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

Region 7 .-Mid-continent 
OIL 

0 

z 

a: CD ::c . 1-CJ 

w 

0:::: 

C)UI 

l:d 

1.1... 

C) 

>-- .... ~d 

.....] 

...... 

(I) 

a:N 

~d 

0:::: 

a.. 0 

ci 

\ \ 

\ 

\ 

0.0 0.6 

ESTIMATES 

ME: AN - MEDIAN - 95% 

75% 

SOY. 

25% 

5% 

MODE 

\ S.D. 

"" "" I'---

1.2 1.8 2.4 --3.0 3.6 4.2 

BILLION BARRELS RECOVERABLE OIL 

-

-

-

-

-

-

-

4.8 

1. 12 

0.91 

0. 31 1 

0.59 

0.91 

1. 41 

2.67 

0.59 

0.82 

5.4 6.0 

~ ASSOCIATED-DISSOLVED GAS 0 

z 

a: CD ::c . 1-CJ 

w 

0:::: 

ow 

l:d 

Lo.... 

C) 

>-- .... 

~d 

__] 

(I) 

a:N 

(I) • 

00 

0:::: 

a.. 0 

ci 

\ 

\ 

~ 

\ 

o.o 0.8 

ESTIMATES 

MEAN, - 1. 35 

MEDIAN - 1.09 

9SY. - 0.37 

7SY. - 0.70 

SOY. - 1.09 

2SY. - 1.69 

SY. - 3.20 

MODE: - 0.71 

\ S.D. - 0.98 

~ "'-._ 

1'---t---

1.6 2.4 3.2 4.0 4.8 5.6 6.4 7.2 e.o 

TRILLION CUBIC FEET RECOVERABLE GAS 

TOTAL GAS 

0 

z 

a: CD ::c . 1-CJ 

w 

0:::: 

Ow 

l:d 

1.1... 

C) 

>-- .... ~c:i 

__] 

...... 

(I) 

a:N 

(I) • 

ao 

0:::: 

a.. 0 

d 

\ ESTIMATES 

ME: AN - 5.10 

\ MEDIAN - 4.35 

95% - ·]. 84 

75% - 3.03 

50% - 4.35 

\ 25% - 6.31 

5% ... 10.89 

MODE - 3.04 

\_ S.D. .. 3.12 

--~ 

---- j 

0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

0 

z 

a: CD ::c . 1-CJ 

w 

0:::: 

Ow 

1:• 0 

Lo.... 

C) 

>-- .... 1- . ......o 

__] 

(I) 

a:N 

(I) • 

ao 

0:::: 

a.. 0 

d 

\ ESTIMATES 

MEAN - 3.76 

\ MEDIAN - 2.95 

95% - 0.94 

7SY. - 1.86 

SOY. - 2.95 

1\ 2SY. - 4.72 

SY. - 9.30 

MODE - 1.82 

\ S.D. - 2.96 

~ r---...._ -

0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

Region 8.-Michigan Basin 
OIL 

0 

z 

a:cc I. 

f--40 

w 

0::: 

Oco 

l: . 0 

IL. 

0 

>-- ... t:ci 

_J 

(IJ a:N 

a:Jci 

0 

0::: 

(L 

0 

ci 

\ ESTlMATES 

MEAN - 0.87 

MEDIAN - 0.73 \ 95% - 0.30 

75% = 0.51 

50% - 0.73 

\ 25% = 1. 06 

5% = 1. 87 

MODE - 0.63 

S.D. - 0.56 

~ 

-

""" ~ r---

0.00 O.i5 0.00 1.35 1.80 2.25 2.70 3.15 3.60 1.05 i.SO 

BILLION BARRELS RECOVERABLE OIL 

~ ASSOCIATED-DISSOLVED GAS 

0 

z 

a:cc I. 

f--40 

w 

0::: 

OCD 

l::ci 

L.... 

0 

>-- ... 

t:ci 

_] 

...... 

(IJ a:N 

(D • 

00 

0::: 

(L 

0 ci 

\ 

\ 

1\ 

\ 

0.0 0.4 

ESTIMATES 

MEAN = 0.55 

MEDIAN - 0. 44 

95% - o. 18 

75% - 0.30 

50% - 0. 44 

25% - 0.66 

5% = 1. 23 

MODE - 0.461 S.D. = 0.43 

~ r--

0.8 1.2 1.6 2.0 2.4 2.8 3.2 3.6 i.O 

TRILLION CUBIC fEET RECOVERABLE GAS 

TOTAL GAS 0 

z 

a:cc I. 

1--<CJ 

w 

0::: 

a co l::ci 

IL. 

0 

>-- .... t:ci 

_] 

...... 

(D a:N 

(D' 00 

0::: 

(L 

CJ 

ci 

1\ ESTIMATES 

MEAN = 2.69 

\ MEDIAN - 2.40 

95% = 1. 25 

75% = 1. 81 ~ 50% - 2.40 

\ 25% = 3.23 

5% = 5.00 

MODE - 2.09 

\ S.D. = 1. 32 

~ 

""' I'--r--

o.o 1.0 2.0 3.0 1.0 5.o s.o 7.0 e.c 9.0 10.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

0 

z 

a:cc I. 

1--<CJ 

w 

0::: 

a co :rci 

IL. 

0 

>-- ... t:ci 

_] 

(D 

a:N 

(D • 

00 

0::: 

(L 

0 

ci 

\ ESTIMATES I 

[\ MEAN = 2.14 

MEDIAN - 1. 91 \ 95% = 0.85 

75% .. 1. 38 

50% - 1. 91 

\ 25% = 2.68 

5% = 4.42 

1\ MODE - 1.15 

~ S.D. ~ 1. 25 

~ ...____ L__ 

0.0 1.0 2.0 3.0 1.0 5.0 6.0 7.0 8.0 9.0 10.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

Region 9.--Eastern Interior 
OIL 

CJ 

z 

CCCD I . 1--<0 

w 

0::: aUI 

:Lei 

l... 

0 

>-- .... !:::ei 

_.J 

ID 

CCN 

ID ' ao 

0::: 

a.. CJ 

ei 

\ 

\ 

\ 

I0.0 0.4 

ESTIMATES 

MEAN - 0.59 

MEDIAN - 0.46 

95% - 0. 14 

75% - 0.28 

50% - 0.46 

25% - 0.75 

5% - 1.50 

MODE - 0.27 

\ S.D. - 0.49 

~ t----t--- -------

0.8 1.2 1.6 2.0 2.4 2.8 3.2 3.6 4.0 

BILLION BARRELS RECOVERABLE OIL 

~ ASSOCIATED-DISSOLVED GAS 

CJ 

~~ Ic 

I-< 

w 

@5"! 

E:o 

l... 

a 

>-- .... 1--<ei 

...... 

_.J 

IDN CC, 

IDa 

a 

0::: 

a.. 0 

ei 

\ ESTIMATES l 

MEAN - 0.47, 

\ MEDIAN - 0.36 

95% - o. 11 

75% - 0.221 

\ 50% . 0.36 

25% - 0.59 

\ 5% ..... 1. 21 

MODE: e 0.21 

~ S.D. - 0.39 

~ ~----~ 

0.00 0.35 0.70 1.05 1.40 1.75 2.10 2.45 2.60 3.15 3.50 

TRILLION CUBIC fEET RECOVERABLE GAS 

TOTAL GAS 

0 

z 

CCCD I . 1--<0 

w 

0::: aUJ 

:Lei 

l... 

a 

>-- .... 

!:::ei 

_.J 

ID 

(CN 

ID ' ao 

0::: 

a.. CJ 

ei 

\ ESTIMATES 

MEAN - 20.13 

~ MEDIAN - 16.90 

95% - 6.39 

75% = 11.26 

50% - 16.90 

\ 25% "' 25.34 

5% = 45.80 

MODE - 10.33 

""' 

S.D. - 13. 17 

~ r--

o.o 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.:J 100.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

0 

z 

CCCD I . f-oCI 

w 

0::: aUI 

:Lei 

l... 

a 

>-- .... !:::ci 

_.J 

ID 

CCN ID , ao 

0::: 

0... 

CJ 

ei 

\ ESTIMATES 

MEAN = 19.66 

MEDIAN - 16.49 1\ 95% = 5.95 

75% = 10.95 

50% - 16.49 

\ 25% = 25.07 

5% = 43.91 

MODE - 10.90 

~ S.D. - 13. 17 

~~ 

r--- -- - ......... 

0.0 LO.O 20.0 30.0 40.0 50.0 60.0 70.0 80.C 90.0 100.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

Region 10.--Appalachians 
U'1 

~ 

OIL 

0 

z a:CIO 

iEc::i 

w 

0::: 

oco 

~c::i 

~ 

0 

>--"" !::c:i 

_J 

(IJ 

a:t'l 

(IJ' 00 

0::: 

a... 0 

d 

\ ESTIMATES 

MEAN = 0.32 

\ MEDIAN - 0.25 

95% = 0.08 

75% .. 0.16 

50% - 0.25 

\ 25% = 0.41 

5% = 0.80 

~ MODE - 0.16 

\ S.D. = 0.26 

~ 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 

BILLION BARRELS RECOVERABLE OIL · 

ASSOCIATED-DISSOLVED GAS 0 

~CI:! :Co 

.... 

w 

~co ~d 

~ 

0 

>--"" !::c:i 

_J 

(IJ 

O:t'l 

(IJ • 

00 

0::: 

a... 0 

d 

\ ESTIMATES 

MEAN - 0.03 

MEDIAN - 0.03 

\ 95% .. 0.01 

75% - 0.02 

50% - 0.03 

\ 25% = 0.04 

5% - 0.08 

MODE - 0.02 

\ S.D. - I 0,02 

~~~ 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 O.iO O.iS 0.50 

TRILLION CUBIC FEET RECOVERABLE GAS 

TOTAL GAS 

0 

z 

a: :eta 

ESTIMATES 

MEAN - 1--<c::i MEDrAN - w 

0::: 

0 

~co 

d ~ 

0 

t:": 

..... o _J 

(IJ 

O:N 

ID • oo 

0::: 

a... 0 

d 

95% 

75% 

50% 

25% 

5% 

MODE 

S.D . 

~~ 0.0 O.i 0.8 1.2 1.6 2.0 2.'1 2.8 3.2 

TRILLION CUBIC FEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

~ 

0 

"' 

-

-

= 

-

-

= 

0.09 

0.03 

0.01 

0.02 

0.03 

0.06 

0.35 

0.21 

0.32 

3.6 i.O 

ZCIO a:N 

:::cESTIMATES 

1--<d 

w 

~~ ~. 

~0 

0 

>--i§ 

..... 

..... 0 _J 

!I?f! ID, 

Oo 

~§ d 

MEAN .. MEDIAN - 95% .. 75% - 50% -

\ 25% ... 5% - MODE -

\ S.D. -

" '---

0.0 O.B 1.6 2.1 3.2 i.O '\.8 5.6 6.i 

TRILLION CUBIC FEET RECOVERABLE GAS 

0.06 

0.00 

0.00 

0.00 

0.00 

0.00 

0.30 

0.03 

0.32 

- 7.2 8.0 

Region 11.--Atlantic Coast 
OIL 

0 

z 

CCa:~ :c . f-<0 

w 

0::: 

olD r. 

t.... 

0 

0 

>-<..-

....... 

,_.0 

_) 

...... 

lD 

CCN lD • oo 

0::: 

a... 0 

ci 

\ ESTIMATES 

!\ MEAN - 10.85 

\ MEDIAN - 9.38 

95% - 3.77 

75% - 6.62 

50% - 9.38 

\ 25% - 13.49 

5% - 21.95 (\, MODE - 8.15 

~ S.D. - 6.35 

~-r------ ---··--- 0.0 ~.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 15.0 50.0 

BILLION BARRELS RECOVERABLE OIL 

~ ASSOCIATED-DISSOLVED GAS 

0 

z 

CCa:~ 

:c . f-<0 

w 

0::: 

0(t) 

r. 

0 

t.... 

0 

><..-

!::ci 

_) 

lD 

CCN lD • 00 

If 0 

ci 

\ ESTIMATES 

MEAN - 16.66 

1\ MEDIAN - 14.39 \ 95% - 5.66 

75% - 9.92 

50% - 14.39 

\ 25% - 20.85 

5% - 35.14 

MODE - 13.37 

\ S.D. - 9.95 I 

'~ t--- __ j 

0.0 8.0 16.0 ~1.0 32.0 40.0 18.0 56.0 61.0 72.0 80.0 

TRILLION CUBIC PEET RECOVERABLE GAS 

TOTAL GAS 

0 

z 

CCa:~ :c . f-<0 

w 

0::: 

0(t) 

r. 0 

t.... 

0 

><..-

!::ci 

_) 

lD 

CCN lD • 00 

0::: 

a... 0 

ci 

\ ESTIMATES 

MEAN - 57.37 

MEDIAN - 53.47 

\ 95% - 28.52 

75% - 41.63 

50% - 53.47 

\ 25% - 68.85 

5% - 99.00 

MODE - 42.51 

\ S.D. - 23.58 

--

"" ~ 1---

0.0 20.0 10.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0 200.0 

TRILLION CUBIC PEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

0 

z 

CCa:~ 

:c . f-<0 

w 

0::: 

olD r. 

t.... 

0 

0 

>-<..-

....... 

,_.a 

_) 

lD 

CCN 

lD • oo 

0::: 

a... '0 

'ci 

~ ESTIMATES 

1\ MEAN - 40.70 

\ MEDIAN • 35.71 

95% - 16.01 

75% - 26.13 

50% - 35.71 \ 25% - 49.72 

5% - 78.42 

MODE - 28·.98 

~ S.D. - 21.38 

"' ~ t---

o.o 20.0 10.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0 200.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

Region 1 A.-Alaska shelf 
OIL 

~ !'-.. 

ci 

zw a:!'-.. 

Il/1 

f-<ci 

w 

er~ a..., 

E.,.. 

L...ci 

0 

>--~ f-<~ 

>-<ci 

_J 

m.,.. 

a:..-

m- Oci 

er 

a_o 

8 

ci 

1\ ESTIMATES 

MEAN - 1. 38 

MEDIAN - 0.73 \ 95% - 0.00 

75% - 0.00 

50% - 0.73 \ 25% - 1. 72 

5% - 5.23 

MODE - 0.98 

\ S.D. - 2.33 

~ r-----1-

0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 

BILLION BARRELS RECOVERABLE OIL 

~ ASSOCIATED-DISSOLVED GAS 

~ !'-.. 

ci 

Zw 

a: Ill 

iSci 

w @5a 

E, 

0 t... 

0 (I) 

)-o(l) 

f-<~ 

....... 0 __) 

....... 

m.,.. 

a: ... (D~ 

Oo 

ere 11..8 

ci 

~ 

\ 

\ 

\ 

1\. 

0.0 3.5 

ESTIMATES 

MEAN - 2.22 

MEDIAN - 1. 13 

95% - 0.00 

75% - 0.00 

50% - 1. 13 

25% - 2.80 

5% - 7.90 

MODE - 1. 52 I S.D. - 3.74 

I 

~ I--r-- J 

7.0 10.5 li.O 17.5 21.0 24.5 28.0 31.5 35.0 

TRILLION CUBIC PEET RECOVERABLE GAS 

TOTAL GAS 

~ 01 

ci 

z 

a: .... I"'" 

f-<": 0 

w 

er 

0~ E111 

t...ci 

0 

>--~ f-41:1 

:Jci 

~:B (D~ 

Oo 

ere a...8 

ci 

1\ ESTIMATES 

MEAN - 7.25 

\ MEDIAN - 4.99 

95% - 0.00 

75% - 2.49 

50% - 4.99 

\ 25% - 8.63 

5% - 20.21 

MODE - 5.61 

\ S.D. - 12.28 

~ r--- ---

0.0 10.0 20.0 30.0 iO.O 50.0 60.0 70.0 80.0 90.0 100.0 

TRILLION CUBIC PEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

R !'-.. 

ci 

zw a:_ 

ICD 

F-<ci 

w 

er~ 

Oco E.,.. 

t...ci 

0 

>--~ f-<l"l 

-ci __) 

,_. 

m..,. 

CCI/1 

(D~ 

Oo 

Q::o a...8 

ci 

ESTIMATES 

MEAN - 5.03 

MEDIAN - 2.93 

95% - 0.00 

75% - 0.94 

50% - 2.93 

25% - 5.91 

\ 5% - 15.25 

MODE - 4.13 

\ S.D. - 11.70 

i 

\ r---

0.0 15.0 30.0 45.0 60.0 75.0 90.0 105.0 120.0 135.0 150.0 

TRILLION CUBIC PEET RECOVERABLE GAS 

Region !A.--Alaska slope 
(J1 

--J 

OIL 

c. 

z 

a: .:c<D 'I\ ESTIMATES 

MEAN = 12.23 t-o 

w 

a::: 

~~ \ MEDIAN - 10.88 

95% = 4.65 

75% = 7.69 

L... 

0 

0 

>-<.,.. t- . ...... 0 

_] 

a::J 

a: <'I a::J • oo 

a::: 

a... 0 

0 

0.0 4.5 

50% - 10.88 

\ 25% = l5.24 

5% = 24.23 

MODE - 7.35 

\ S.D . = 6.76 

~ ~ !'---r---

9.0 13.5 18.0 22.5 27.0 31.5 36.0 10.5 'lS.O 

BILLION BARRELS RECOVERABLE OIL 

ASSOCIATED-DISSOLVED GAS 

0 

z 

~~ f-0 

w 

a::: 

Oco 

::E • 

L... 

0 

0 

>-< ... ~ci 

_] 

a::J 

a: <'I a::J • 00 

a::: 

a... 0 

ci 

"'\ 

1\ 

\ 

0.0 8.0 

ESTIMATES 

MEAN = 18.88 

MEDIAN - 16.64 

95% = 6.74 

75% = 11.48 

50% - 16.64 

\ 25% = 23.22 

1\ 5% = 37.60 

MODE - 14.00 

\ S.D. = 10.63 

~ 1--- I 

16.0 2'1.0 32.0 'lO.O '18.0 56.0 6'1.0 72.0 80.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

TOTAL GAS 

0 

z 

a: .:c<D 

t-o 

w 

a::: 

Oco 

::E. 

L... 

0 

0 

>-< f- ... 

.....ci 

_] 

a::J 

a: <'I a::J • oo 

a::: 

a... 0 

ci 

\ ESTIMATES 

MEAN - 6.4. 61 

\ MEDIAN - 59.88 

95% = 33.32 

1\ 75% = 47.09 

50% - 59.88 

\ 25% = 76.57 

5% = 109.65 

MODE - 46.59 

\ S.D. = 26.58 

1\ I 

~ J---_ - -- 0.0 25.0 50.0 75.0 100.0 125.0 150.0 175.0 200.0 225.0 250.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

0 

z 

a: .:c<D 

t-o 

w 

a::: 

~~ 

L... 

0 

0 

~"": _,o 

_] 

a::J 

a: <'I a::J • oo 

a::: 

a... 0 

ci 

"""" ESTIMATES 1\ MEAN = 45.73 

MEDIAN - 41.09 \ 95% = 19. 10 

75% = 30.43 

50% - 41.09 

\ 25% = 55.80 

[\ 5% = 89. 12 

MODE - 39.61 

\ S.D. = 24.37 

I~ 

0.0 20.0 40.0 60.0 80.0 

---

100.0 120.0 HO.O 160.0 180.0 200.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

Region !A.-Alaska entire offshore 
OIL 

0 

z 

a: CD :I: . 1--<c 

w 

a:: 

oco 

::Cci 

lo... 

0 

,......,. 

t:a 

....J 

ID a:N 

ID ' oo 

a:: 

0... 0 

d 

\ ESTIMATES f\ MEAN - 1. 49 

i MEDIAN - 1. 35 

95% - 0.58 

75% - 0.96 

50% - 1. 35 \ 25% - 1.89 

5% - 3.02 

1\ MODE - 1. 21 

\ S.D. - 0.84 

~ r--_ 

0.0 0.7 l.i 2.1 2.8 3.5 i.2 i.S 5.6 6.3 7.C 

BILLION BARRELS RECOVERABLE OIL 

~ ASSOCIATED-DISSOLVED GAS 

0 

z a:Q) 

.:I: • J--<0 

w 

a:: 

OtD 

::cci 

lo... 

0 

,......,. 

t:o 

....J 

...... 

ID a:N ID • oo 

a:: 

0... 0 

c:i 

\ ESTIMATES [\ MEAN - 1. 38 

~ MEDIAN - 1. 23 

95% - 0.48 

75% - 0.84 

50% - 1. 23 \ 25% - 1. 72 

L\ 5% - 2.85 

MODE - 1.00 

\ S.D. - 0.81 

~ t--

0.0 0.6 1.2 1.8 2.4 3.0 3.6 1.2 1.8 5.1 6.0 

TRILLION CUBIC PEET RECOVERABLE GAS 

TOTAL GAS 

0 

z a:Q) 

.:I: • J--<0 

w 

a:: 

\ ~ 

\ 

ESTIMATES 

MEAN - 2.54 

MEDIAN - 2.23 

95% - 0.90 

75% - 1. 53 

50% - 2.23 OtD 

::cc:i 

lo... 

0 \ 25% 

5% 

MODE 

- 3.16 

- 5.16 

1. 53 ,..... .... I-< • _.o 

....J 

ID a:N ID • oo 

a:: 

0... 0 

ci 

0.0 1.2 

-

,\, S.D. - 1. 49 

~-~ ,._____ I 

2.1 3.6 1.8 6.0 7.2 8.1 9.6 10.8 12.0 

TRILLION CUBIC PEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

0 

z 

a: CD .:I: • f--<0 

w 

a:: 

oco 

::Cci 

lo... 

0 

,..... ... t:d 

....J 

ID a:N 

ID ' oo 

a:: 

0... 0 

ci 

\ 

\ 

\ 

~ 

o.o 1.0 

ESTIMATES 

MEAN - 1. 15 

MEDIAN - 0.84 

95% - 0. 16 

75% - 0.38 

50% - 0.84 

25% - 1. 61 

5% - 3.50 

MODE - 0.37 ~.D. - 1. 25 

~ 1----. 

2,0 3.0 i.O 5.0 6.0 7.0 8.0 9.0 10.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

Region 2A.-Pacific Coast shelf 
OIL 

0 

z 

(CCD 

I. 

f-<0 

w 

a::: 

CliO 

:Eci 

lL 

0 

>-< .... 

\ 

\ 

~ 

ESTIMATES ' MEAN - 2.35 

MEDIAN - 2.05 

95% - 0.58 

75% - 1. 20 

50% - 2.05 

25% - 3.27 

5% - 6.05 

MODE - 1. 67 t;ci 

_J 

(I) 

(CC'\1 

(I). 

Do 

a::: 

\ S.D. - 2.02 

l'\, 

""-

1--- '------ ~--·--

Q.. 

0 

d 

o.o 1.6 3.2- 1.8 6.1 8.0 9.6 11.2 12.8 11.i 16.0 

BILLION BARRELS RECOVERABLE OIL 

~ ASSOCIATED-DISSOLVED GAS 

0 

z 

(CCD 

:r· f-<0 

w 

a::: 

C)IO 

:Ed 

lL 

0 

>-< .... t;ci 

_J 

(I) 

(CC'II 

(I). 

Do 

a::: 

n.. 0 

d 

\ 

\ 

\ 

\ 

o.o 2.5 

ESTIMATES I 

;MEAN - 2. 72: 

-MEDIAN - 2.23 

95% - 0.65 

75% - 1. 34 

50% - 2.23 

25% - 3.63 

5% - 7.56 

MODE - 1. 10 

S.D. - 2.42 

" !'---t---

5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

TOTAL GAS 0 

z 

(CCD X. 

f-<0 

w 

a::: 

C)IO 

\ 

~ 

EST I MAT~ MEAN - 4.371 MEDIAN - 4.27 

95% - 1. 90 

75% - 3.04 

50% - 4.27 :Ed 

lL 

0 

>-< .... t;ci \ 25% 

5% 

MODE 

S.D. 

- 6.03 

- 10. 17 

- 3.56 

2.95 _J 

(I) 

(CC'\1 

(I). 

Do 

a::: 

Q.. 0 

d 

0.0 3.0 

\ - [\. I 

~ ..___ I-- I 

6.0 9.0 12.0 15.0 18.0 21.0 21.0 27.::J 30.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

R 

en 

ci 

Zca 

(Cr-. 

X" 

f-<d 

w 

ll:::N 

C) CD :t:111 ci lL 

0 

CD 

>-<~ f-<, 

-o 

_J 

~; m- od 

a::: 

Q..8 

d 

\ 

\ 

~ 

0.0 1.1 

ESTIMATES 

MEAN - 1.65 

MEDIAN - 1.58 

95% - 0.79 

75% - 1. OS 

50% - 1.58 

25% - 2.49 

5% - 4.86 

MODE - 1. 13 

\ S.D. - 1. 70 

I 

J 

I~ I ......__ J 

2.8 1.2 5.6 1.0 8.1 9.8 11.2 12.6 1~.c 

TRILLION CUBIC fEET RECOVERABLE GAS 

Region ZA.-Pacific Coast slope 
0' 

0 

OIL 

0 

z 

CI:CD I 0 

1:--<0 

w 

0::: 

Ota L:: . 0 

I.... 

0 

>-o..,. 

~c:i 

_J 

OJ 

CI:N OJ • 00 

~ 0 

ci 

" 1\ 

\ 

0.0 1.8 

ESTIMATES 

MEAN "' 3.84 

MEDIAN - 3.58 

95% - 1. 72 

75% - 2.60 

50% - 3.58 

\ 25% - 4.89 

5% - 7.94 

\ MODE - 3.24 

\ S.D. = 2. 19 

~ r---

' 3.6 5.4 7.2 9.0 10.8 12.6 14.4 16.2 18.0 

BILLION BARRELS RECOVERABLE OIL 

ASSOCIATED-DISSOLVED GAS 0 

z cr:CD Io 

1:--<0 

w 

0::: 

oco 

L::ci 

L.... 

0 

>-<..,. 

~ci 

..J 

OJ 

CI:"' 

OJ' 00 

0::: 

CL 

0 

ci 

\ 

[1 

\ 

0.0 2.0 

ESTIMATES 

MEAN .. 4.08 

MEDIAN - 3.67 

95% - 1. 69 

75% - 2.65 

50% - 3.67 

\ 25% - 5.24 

5% - 8.87 

MODE - 2.88 

\ S.D. .. 2.55 

~ r---

1.0 6.0 8.0 10.0 12.0 H.D 16.0 18.0 20.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

TOTAL GAS 

0 

z 

CI:CD :c 0 

1:--<0 

w 

0::: 

Oco L:: . 0 

I.... 

0 

>-o..,. 

!::c:i 

..J 

m 

m. CI:N 

00 

0::: 

CL 

0 

ci 

\ ESTIMATES 

MEAN - 6.89 

\ MEDIAN - 6.93 

95% .. 3;73 

75% = 5.36 

50% - 6.93 

\ 25% - 9.05 

5% .. 13.55 

MODE - 5.28 

\ S.D. - 3.31 

~ r--- -

0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

0 

z 

CI:CD I 0 

1:--<0 

w 

0::: 

0 CD 

L::ci 

I.... 

0 

>-< .... 

~c:i 

..J 

OJo 

~~ 

0 

0::: 

CL 

0 

ci 

\ ESTIMATES 

MEAN = 2.81 

MEDIAN- 2.79 

~ 95% - 1. 20· 

75% - 1. 92! 

50% - 2.79 

\ 25% ... 4.02 

5% - 7.05 

MODE - 1. 57 

\ S.D. .. 2. ll: 

\. 

""-. ~ 1--- ---- ~ 

0.0 1.8 3.6 5.4 7.2 9.0 10.8 12.6 14.4 16.2 18.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

Region 2A.-Pacific Coast entire offshore 
0' 

~ 

OIL 

a 

:z 

a: CD "" "" 

ESTIMATES 

MEAN - 3.97 

iSci 

w 

cr. 

Ora 

E • 

\ MEDIAN - 3.59 

9S% - 1. 32 

7S% 2.46 

L._ 

0 

a 

>-· ... ....... 

......,a 

_] 

ID 

<I:N 

ID • oa 

a::: 

Q_ 

a 

ci 

o.o 1.i 

- r\ SO% - 3.59 

\ 25% - S.03 

S% - 7. 88' 

MODE - 3. o8: 

~ S.D. - 2. 081 

~ r---

2.8 i.2 5.6 7.0 8.i 9.8 11.2 12.6 J<t.O 

BILLION BARRELS RECOVERABLE OIL 

ASSOCIATED-DISSOLVED GAS 

0 

:z 

(CCD 

I 0 

f--<0 

w 

a::: 

Ow E. 

L._ 

0 

0 

~ .... ~c::i 

_] 

ID 

<I:N 

ID • oo 

e::: 

Q_ 

0 

d 

--~ 

0.0 2.0 

ESTIMATES 1 

MEAN - S. 70: 

\ MEDIAN - 5.22 

9S% ... 2.22 

1\ 75% - 3. 71! 

SO% - S.221 

\ 25% - 7. 10. 

S% - 10. 97' 

MODE - 3.61 

~ S.D. - 2.80 

~ 1----1--

1.0 6.0 8.0 10.0 12.0 li.O 16.0 18.0 20.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

TOTAL GAS 

0 

:z 

(CCD 

~d 

w 

a::: 

Ow 

E • 

u.. 

0 

0 

~ .... ...... 0 

._.o 

_] 

...... 

ID 

<I:N ID • oo 

a::: 

Q_ 

0 

d 

\ ESTIMATES 

MEAN - 45.31 

\ 

MEDIAN - 41.03 

9S% - 21.97 

7S% - 32.07 

SO% - 41.03 

\ 2S% - S3.86 

5% - 79.20 

MODE - 37.82 

I~ S.D . - 18.50 

~ 

--- ·--L__ 

0.0 15.0 30.0 i5.0 60.0 75.0 90.0 105.0 120.0 135.0 150.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

~ 

:z 

(CCD 

I • f--<0 

w 

a::: 

Ow 

E • 

L._ 

0 

0 

~ ... ...... 0 

........ 0 

_] 

ID 

<I:N 

ID • oo 

a::: 

Q_ 

0 

d 

1\ ESTIMATES l 

MEAN - 39.61 

MEDIAN - 3S.45 

\ 9S% - 17.44 

7S% - 26.45j 50% - 35.45, 

\ 25% - 48. 16 

5% - 74. 12 

MODE - 29.41 

\ S.D. - 18.28 

~ ~ 

~ t---

0.0 15.0 30.0 i5.0 60.0 75.0 90.0 105.0 120.0 135.0 150.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

Region 6A.-Gulf of Mexico shelf 
0'-

N 

OIL 

a 

z 

(CCD 

I. 

f-<C 

w 

0::: 

ow 

~d 

I:... 

0 

>-<-r 

!::ci 

__.J 

....... 

m 

(CN 

ID • 00 

0::: 

Q.. 

0 

d 

"' 1\ 

o.o 1.0 

ESTIMATES 

MEAN - 2.53 

\ MEDIAN - 2.21 

95% - 0.94 

75% - 1. 58 

50% - 2.21 

\ 25% - 3.14 

5% - 5. 19 

MODE - 1. 73 

"\ S.D. - 1. 37 

""' ~ 

2.0 3.0 1.0 --------5.0 6.0 7.0 8.0 9.0 10.0 

BILLION BARRELS RECOVERABLE OIL 

ASSOCIATED-DISSOLVED GAS 

a 

z 

a: CD I. 

f-<C 

w 

0::: 

Ow 

~. 

I:... 

0 

0 

>-<-r f-< • ....,o 

__.J 

..... 

m 

m. CI:N 

oo 

0::: 

Q.. 

0 

d 

""' ESTIMATES f\ MEAN - 4.38 

MEDIAN - 3.85 \ 95% - 1. 64 

75% - 2.69 

50% - 3.85 

\ 25% - 5.47 

1\ 5% - 8.92 

MODE - 3.20 

\ s;D. - 2.38 

~ 

"-......... 1---r0.0 1.8 3.6 5.1 7.2 9.0 10.8 12.6 11.1 16.2 18.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

TOTAL GAS 

a 

z 

CI:CD 

I • f-< c 

w 

0::: 

Ow 

~. 

I:... 

0 

0 

>-<..,. 

f-< • ....,o 

__] 

..... 

m 

m. CI:N 

oo 

0::: 

Q.. 

0 

d 

\ ESTIMATES 

MEAN - 26.53 

MEDIAN - 23.49 I\ 95% - 11. 11 

75% - 17.26 

50% - 23.49 

\ 25% - 32.591 

5% - 51.78 

MODE - 20.22 

\ S.D . - 13.80 

~ 

~ 

- 1--- - 0.0 15.0 30.0 15.0 60.0 75.0 90.0 105.0 120.0 135.0 150.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

a 

z 

CI:CD :I:. 

f-<C 

w 

0::: 

Ow 

~. 

I:... 

0 

0 

>-<..,. f-< • ,__.a 

__.J 

...... 

m 

tt:N m. 

oo 

0::: 

Q.. 

0 

d 

\ ESTIMATES 

MEAN - 22. 16 

\ MEDIAN - 18.92 

95% - 7.62 

75% - 12.85 

50% - 18.92 

\ 25% - 27.911 

5% - 47.731 

MODE - 13.66 

\ S.D. - 13.59 

I~ I--

0.0 15.0 30.0 15.0 60.0 75.0 90.0 105.0 120.0 135.0 150.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

Region 6A.-Gulf of Mexico slope 
ow 

OIL 

0 

z 

a: 

z:CD 

~-<a 

w 

l:r 

~~ 0 

L... 

C) 

>--., 

...... . ...... 0 

~ 

CD 

CCN 

CD • ao 

l:r 

Cl.. 

0 

ci 

0.0 1.8 

~ ESTIMATES 

"" 

MEAN - 6.49 

\ MEDIAN - 6.14 

95% - 3. 13 

75% - 4.72 

50% - 6.14 

\ 25% - 7.84 

5% - 11.06 

MODE - 5.68 

'\ S.D. - 2.49 

""' "-

"'--r--

3.6 S.i 7.2 9.0 10.8 12.6 1i.i 16.2 18.0 

BILLION BARRELS RECOVERABLE OIL 

ASSOCIATED-DISSOLVED GAS 

0 

z 

CI:co 

z: • f-4CI 

w 

l:r 

Oca :::c • 0 

~ 

>--.-

~0 

~ 

~~ CDo 

C) 

l:r 

a.. -o 

ci 

o.o 3.0 

~ ESTIMATES 

1\ MEAN - 10.07 

\ MEDIAN - 9.59 

95% - 5.26 

75/. - 7.44 

50% - 9.59 

1\ 25% - 12. 19 

5% - 16.88 

MODE - 7.85 

\ S.D. ... 3.68 

~ 

~ 1---

6.0 9.0 12.0 15.0 18.0 21.0 2i.O 27.0 30.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

TOTAL GAS 

0 

z 

a: CD ;:r • f-4C1 

w 

l:r 

Ocg 

:::c: • 

L... 

C) 

0 

>-.-

t:o 

~ 

...... 

CD 

O:N Ill • ao 

l:r 

a.. 0 

ci 

'\ ESTIMATES 

MEAN - 71.84 

\ MEDIAN - 68.68 

95% - 41.66 

75% - 55.40 

i\ 50% - 68.68 

\ 25% - 84.31 

5% - 114. 15 

MODE - 65.41 

\ S.D . - 23.08 

1\ 

"" "----i--

0.0 20.0 iO.O 60.0 80.0 100.0 120.0 1i0.0 160.0 180.0 200.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

0 

z: 

a: CD ::c . 1--<0 

w 

l:r 

Oca :::c • 

0 

Lo.... 

C) 

>--.-

...... . ...... o ~ 

Ill 

CCN 

CD • ao 

Q:: 

Cl.. 

0 

ci 

~ ESTIMATES 

MEAN - 61.77 ~ MEDIAN - 58.10 \ 95% - 32.46 

75% - 45.74 

50% - 58. 10 

\ 25% - 73.91 

5% - 103.40 

1\ MODE - 49.52 

~ S.D . - 22.78 

~ --- -

- 0.0 20.0 iO.O 60.0 80.0 100.0 120.0 liO.D 160.0 180.0 200.0 

TRILLION CUBIC FEET RECOVERABLE GAS 

Region 6A.-Gulf of Mexico entire offshore 
OIL 

U'l 

CD 

ci 

~:8 I • 1'--'0 

w 

o:::_ 

a~n l:: • 

0 

(&_ 

a ... >-<n 1'--' • ....... o ...J 

(D" 

a:- (D • ao 

0::: 

11...8 

ci 

~ 

~ 

\ 

~ 

o.o l.i 

ESTIMATES 

MEAN - 1. 29 

MEDIAN - 0.94 

95% - 0.00 

75% - 0.37 

50% - 0.94 

25% - 1. 79 

5% - 3.93 

MODE - 0.45 

S.D. - 1. 41 

J 

'\.., 

"---r--- l -~--

2.8 i.2 5.6 7.0 8.i 9.8 11.2 12.6 1'\.0 

BILLION BARRELS RECOVERABLE OIL 

~ ASSOCIATED-DISSOLVED GAS In 

CD 

ci 

~:8 I• 

('--oO 

w 

0::: 

al::"! 0 

(&_ 

a 

>-< ... 1'--'l'l 

....... ci ...J 

....... 

(D 

a:" m- ao 

0::: 

0....8 

ci 

~ ESTIMATES l 

MEAN - 1.55 

\ MEDIAN - 1.14 

95% - 0.00 

75% - 0.45 

50% - 1. 14 

\ 25% - 2.15 

5% - 4.56 

\ MODE - 0.42 

\_ S.D . - 1. 68 

~ t---1-- - '----- -

0.0 l.i 2.8 i.2 5.6 7.0 8.i 9.8 11.2 12.6 1'\.0 

TRILLION CUBIC PEET RECOVERABLE GAS 

TOTAL GAS 

§! 

0 

z 

(CN 

~f?! 0 

w 

0::: 

a a; l::ltl 

t...ci 

a 

i:~ 

:3ci 

~:§I (D~ 

ao 

0:::0 11...8 

ci 

\ 

\ 

0.0 i.O 

ESTIMATES 

MEAN - 8.22 

MEDIAN - 7.31 

95% - 2.21 

75% - 4.81 

50% - 7.31 

\ 25% - 10.62 

5% - 17.86 

MODE - 5.28 

~ S.D. - 5.05 

~ 1---,..__ 

8.0 12.0 16.0 20.0 21.0 28.0 32.0 36.0 iO.O 

TRILLION CUBIC PEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

i 

0 

z 

(CG:I ICD 

1'--'": 0 

w 

0::: a co l::tl; 

t...ci 

a 

>-< .... l.'-'l51 

:Jd 

(DN 

CC01 

(D~ 

ao 

0:::0 0....8 

ci 

\ ESTIMATES 

MEAN - 6.68 

MEDIAN - 5.78 

t\ 95% - 1. 12 

75% - 3.59 

SO% - 5.78 

\ 25% - 8.87 

5% - 15.61 

MODE - 4.98 

~ S.D. - 4.76 

! 

~r--r-,... 

- o.o 3.5 7.0 10.5 11.0 17.5 21.0 21.5 28.0 31.5 35.0 

TRILLION CUBIC PEET RECOVERABLE GAS 

Region llA.--Atlantic Coast shelf 
0'-

Ul 

OIL 

0 

01 

0 

z 

a:~ i5o 

w 

a::: 

0~ :EU1 0 r..... 

0 

>--~ I-t . ...... o _] 

aJ a: CD aJ .... 

oo 

a::: 

(L8 

0 

\ ESTIMATES 

MEAN - 4.14 

\ MEDIAN - 3.56 

95% - 0.00 

!\ 75% - 1. 72 

50% - 3.56 

\ 25% - 5.96 

5% - 10.68 

MODE - 1. 13 

~ S.D. - 3.59 

~ 

--- -- - . 

0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 

BILLION BARRELS RECOVERABLE OIL 

ASSOCIATED-DISSOLVED GAS 0 

01 

0 

z 

a:~ 

iSo 

w 

a::: 

0~ :EU1 0 r..... 

0 

...... 

~~ o _] 

aJ a: CD aJ .... 

oo 

a::: (L 8 

0 

\ ESTIMATES 

MEAN - 4.84 

\ MEDIAN - 4.21 

95% .. 0.00 

1\ 75% - 2.03 

50% - 4.21 \ 25% - 6.97 

5% - 12.95 

MODE - 1. 30 

S.D. - 4.24 

~ ~!"---

r--

o.o 3.0 6.0 9.0 12.0 15.0 18.0 21.0 2i.O 27.0 30.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

TOTAL GAS ~ 01 

ci ""\ z.., 

CI:OI 

:rr-. 1\ I-to 

w 

:E, ~m 0 u.. 

0 co >-- 01 f-tl"l 

...... 0 _] 

~81 m-

~o (L8 

0 

\ 

\ 

\ ~ 

~ '-----

ESTIMATES 

MEAN - 15.44 

MEDIAN - 15. 16 

95% - 5 .. 09 

75% - 10.27 

50% - 15. 16 

25% - 21.48 

5% - 34.47 

MODE - 14.84 

S.D. - 9.59 

r--

0.0 7.0 H.O 21.0 28.0 35.0 i2.0 i9.0 56.0 63.0 70.ct 

TRILLION CUBIC fEET RECOVERABLE GAS 

NON-ASSOCIATED GAS ~ 01 

0 

z~ 

a: ... :rr-. 

I-to 

w 

~IR :f:Ln 

r.....o 

0 

>--~ f-tl"l 

-o _] 

~18 m- oo 

a::: 

(LO 

8 

0 

\ 

~ \ 

""' ~ r--

ESTIMATES 

MEAN - 10.59 

MEDIAN - 10.09 

95% - 0.00 

75% - 5.82 

50% - 10.09 

25% - 15.56 

5% - 27.02 

MODE - 3.72 

S.D. - 8.61 

I 

0.0 6.0 12.0 18.0 2i.O 30.0 36.0 i2.0 i8.0 54.0 60.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

Region llA.-Atlantic Coast slope 
OIL 

i 

ci 

z .. cc~ :c. 

1---o 

w 

!511 

411! 0 L.... 

0 

N 

>-<~ ...... 

...... 0 ....] 

~I§! m-

~d Q....O 

8 

d 

\ ESTIMATES 

ME: AN - 5.43 

MEDIAN - 4.95 1\ 95% - 1.10 

75% - 2.96 

SO% - 4.95 

\ 25% - 7.62 

5% - 12.88 

~ MODE - 3.86 

~ S.D. - 3.86 

~'.. 

"-... 

'--r--

0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0 

BILLION BARRELS RECOVERABLE OIL 

~ ASSOCIATED-DISSOLVED GAS 

i 

ci 

z .. CCCD 

:c .... 1---d 

w 

::t:. !5~ 

L....o 

0 N 

>-<~ ...... 

...... 0 ...J 

~s m-

~d 

a....§ 

d 

\ ESTIMATES 

ME: AN - 6.39 

L MEDIAN - 5.71 

95% - 1. 15 

75% - 3.36 

soz - 5.71 

\ 25% - 8.77 

5% - 14.95 

r\. MODE - 4.68 

"" 

S.D. - 4.56 

I 

~ 

~ 

----r----

0.0 3.0 6.0 9.0 12.0 15.0 18.0 21.0 2-t.O 27.0 30.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

TOTAL GAS 

0 

z 

CCCD :::c • ..... 0 

w 

0:: 

OCD 

::t:c;; 

L.... 

0 

>-<.-

!::o 

...J 

(D 

CCN 

(D • 

00 

0:: 

0... 0 

d 

-

!"\ ESTIMATES 

ME: AN - 23.66 MEOI~- 22.12 

1\ 95% - 9.17 

75% - 16.05 

soz - 22.12 

\ 25% - 29.58 

5% - 42.82 

MODE - 19.781 

~ S.D. - 10.84 

I 

- --

~ r--- I 

0.0 8.0 16.0 2-t.O 32.0 iO.O 48.0 56.0 6'1.0 72.0 EK>.C 

TRILLION CUBIC fEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 0 

.... 

z ccCD 

:co 

..... 

w 

0:: oca 

::t:d 

L.... 

0 

>-< .. 

t::o 

...J 

(D 

ccN 

m· 00 

0:: 

a.... 0 

d 

""""" ESTIMATES f\ ME: AN - 17.27 

MEDIAN - 17.00 \ 95% .. 6.50 

75% - 11.68 

50% - 17.00 

\ 25% - 23.42 

5% - 36.35 

MODE - 13.27 

\ S.D. - 9.84 

~ 

""" 1'--r---

o.o 7.0 14.0 21.0 28.0 35.0 i2.0 49.0 56.0 63.0 70.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

Region llA.--Atlantic Coast entire offshore 
0'-

-J 

OIL 

0 

z 

(LCD :r. 

f-oCI 

t.J 

0::: 

Ow 2: • 

lL 

0 

0 

>-o.,.. 

.... . _o 

.J 

-m 

<LN m. 

ao 

0::: 

a.. 0 

d 

\ ESTIMATES 

ME: AN - S1.S9 \ MEDIAN - S2.S9 \ 9Si: - 11.72 

7Si: - 17.93 

so;: - S2.99 

\ 2Si: - S9.02 

Si: - 71.02 

MODE: - S0.11 

\ S.D. - 10.16 

~---

I~ - -- __ j -

0.0 15,0 30.0 i5.0 60.0 75.0 90.0 105.0 120.0 135.0 150.0 

BILLION BARRELS RECOVERABLE OIL 

ASSOCIATED-DISSOLVED GAS 

0 

z 

(LCD 

:r . f-oCI 

t.J 

0::: 

Ow 

:::E: • 

lL 

0 

0 

>-o.,.. 

!::c:i 

.J 

-m 

<LN m. 

00 

0::: 

a.. 0 

d 

) 

\ ESTIMATES 

ME: AN - 93.55 

\ MEDIAN - 89.91 

95X - 68.19 

75X - 79.87 

sox - 89.91 

\ 25X - 102.38 

Si: - -126.32 

MODE: - 86.58 

\ S.D. - 19.99 

1\ 

~ r--_ - - -- ·-- 0.0 25.0 50.0 75.0 100.0 125.0 150.0 175.0 200.0 225.0 250.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

TOTAL GAS 

0 

z 

a:: CD :X:· f-oCI 

t.J 

0::: 

o., 

2: • 

lL 

0 

0 

>-o,.. 

..... 

-o 

.J 

-m 

<LN m. 

oo 

0::: 

a.. 0 

d 

~ ESTIMATES I 

1\ MEAN - 126.79 

~ MEDIAN - 111.21 

95i: - 322.531 

7Si: - 372.991 

so;: - 111.21 

\ 2Si: - 166.35 

5i: - 567.91 

MODE - 395.98 

\ S.D. - 78.48 

'\. 

_ ..... o.o as.o 110.0 255.0 31o.o 125,0 51o.o 

""-

595.0 seo.o -7&5.0 eso.o 

TRILLION CUBIC fEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

0 

z 

a:: CD .r. 

f-oCI 

t.J 

0::: 

Ow 

2:d 

lL 

0 

~"': -o 

.J 

-m 

<LN 

~d 

0::: 

0... 

0 

d 

1\ ESTIMATES 

MEAN - 333.21 

MEDIAN - 321.15 

\ 95i: - 235.611 7Si: - 281.59 

so;: - 321.15 

\ 25i: - 371.92 

5i: - 168.15 

MODE: - 309.82 

\ S.D. - 75.89 

1\ 

""' 1'---

0.0 70.0 110.0 210,0 

--

280.0 350.0 i20.0 190.0 - 560.0 630.0 700.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

Entire onshore 
OIL 

0 

z 

a: ::I: CD 

..... c:i 

w 

0::: 

~~ 0 

to... 

0 

:=:--: 

...... o _J 

...... 

m 

m. 

a;:N 

oo 

0::: 

0.... 

0 

d 

\ 

!\ 

\ 

1\ 

" ~ 

ESTIMATES 

MEAN - 17.60 

MEDIAN - 16.28 

95% - 9.15 

75% - 12.95 

50% - 16.28 

25% - 20.66 

5% - 30.18 

MOD£ - 14.381 

S.D. - 6.88 

-- --·-

0.0 6.0 12.0 18.0 21.0 30.0 36.0 12.0 18.0 51.0 60.0 

BILLION BARRELS RECOVERABLE OIL 

~ ASSOCIATED-DISSOLVED GAS 00 

0 

z 

a:: CD ::r::: . ,_.o 

w 

0::: 

oca 

l::d 

~ 

>-- .... ~ci _J 

m a::N m. 

oo 

0:: 

0.... 0 

ci 

~ ESTIMATES 

MEAN - 25.28 

\ MEDIAN - 23.38 

95% - 12.83 

75% - 18.21 

50% - 23.38 \ 25% - 30.31 

5% - 44.61! 

i\ MODE - 18.75 

~ S.D. - 10.50 

I~ 

0.0 8.0 16.0 21.0 32.0 10.0 ----i8.0 56.0 Si.O 72.0 80.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

TOTAL GAS 

0 

z 

a;: CD :I: . ..... CJ 

w 

0::: 

OCD l:: . 

to... 

0 

0 

>-- .... ...... 

......o 

_J 

-m 

a;:N 

m. 

oo 

0::: 

0.... 0 

ci 

.......... 

1\ 

\ 

\ 

\ 

f"'-~ 

ESTIMATES 

MEAN - 113.41 

MEDIAN - 109.27 

95% - 72.04 

75% - 91.28 

50% - 108.27 

25% - 128.86 

5% - 166.84 

MODE - 110.97 

S.D. - 30.42 

~'---~ 0.0 25.0 50.0 75.0 100.0 125.0 150.0 175.0 200.0 225.0 250.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

0 

z 

a;: CD ::r::: • ,_.o 

w 

0:: 

0U) 

l:: . 0 

to... 

0 

>-- .... ~ci 

_J 

...... 

m a::N m. 00 

0:: 

0.... 0 

ci 

........... 

1\ 

\ 

~ \ 

~ 

""' "----

ESTIMATES 

MEAN - 88.15 

MEDIAN - 83.48 

95% - 50.57 

75% - 67.90 

SO% - 83.48 

25% - 103.79 

5% - 139.07 

MODE: - 76.50 

S.D. - 28.56 

~~--- - 0.0 25.0 50.0 75.0 100.0 125.0 150.0 175.0 200.0 225.0 250.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

Entire shelf 
OIL 

0 

z 

(L 

:J:CD f-oo 

w 

0::: 

0 

:~:co 

[&_0 

0 

i:~ ...... 0 

_] 

...... 

aJ 

(LN 

aJ • oo 

0::: 

0.. 

0 

0 

"" ESTIMATES 

MEAN - 10.40 

MEDIAN - 9.6S 

1\ 9SY. - 4.22 

7SY. - 7.09 

SOY. - 9.6S 

\ 2SY. - 12.90 

SY. - 19.17 

MODE - 7.74 

~ S.D. - 4.93 

~ r----

0.0 3.5 7.0 10.5 11.0 17.5 21.0 24.5 28.0 31.5 35.0 

BILLION BARRELS RECOVERABLE OIL 

~ ASSOCIATED-DISSOLVED GAS 

0 

z 

(LCD 

:c. 

(-oo 

w 

0::: 

Occ 

:~::. 

[&_ 

0 

0 

i:~ ...... 0 

_] 

...... 

aJ 

(LN 

aJ . oo 

0::: 

0.. 0 

0 

-

1'\ ESTIMATES 

MEAN - 14. 1S 

\ MEDIAN - 13.20 

9SY. - S.91 1\ 7SY. - 9.72 

SOY. - 13.20 

\ 2SY. - 17.SO 

SY. - 26.17 

MODE - 11. 10 

~ S.D. - 6.S9 

'~ r---

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 15.0 50.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

TOTAL GAS 

0 

z 

(LCD 

:J: • (-oO 

w 

0::: 

Ceo 

%:: • 0 

[&_ 

0 

>-< .... !::a 

_] 

...... 

aJ 

CLN aJ . 00 

0::: 

0.. 0 

0 

\ 

~ 

\ 

\ 

1\ 

~ I'--

ESTIMATES 

MEAN - S3.S8 

MEDIAN - SO.S3 

9SY. - 28.64 

7SY. - 40.06 

SOY. - SO.S3 

2SY. - 62.83 

SY. - 87.09 

MODE: - 47.03 

S.D. - 21.02 

0,0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0 200.0 I 

TRILLION CUBIC fEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

0 

z 

(LCD 

:J: • (-oO 

w 

0::: 

Occ r. 

0 

[&_ 

0 

>-<..,. 

...... . .....,o 

_] 

...... 

aJ 

CLN aJ • oo 

0::: 

0.. 

0 

0 

\ 

Ll 

\ 

\ 

1\ 

""' I'-- --

ESTIMATES 

MEAN - 39.43 

MEDIAN - 3S.72 

9SY. - 17.21 

7SY. - 26.S7 

sox - 3S.72 

25Y. - 47.S3 

SY. - 71.64 

MODE - 26.98 

S.D • - 19.96 

0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0 200.0 

TRILLION CUBIC fE.ET RECOVERABLE GAS 

Entire slope 
OIL 

a 

z 

a: co :X: . ~CI 

w 

a:::: 

0(0 

%:• a t... 

0 

>-<...-

~. 

...... a _] 

-

aJ a:N aJ • oa 

a:::: 

a... a 

d 

~ 01/03/81 

ME: AN - 28.00 

ME:OIAN - 26.80 1\ 95% - 16.86 

75% - 22.37 

50% - 26.80 

\ 25% - 32.45 

5% - 43.48 

MODE - 25.95 

~ S.D. - 8.46 

~ ......_ 0.0 7.0 14.0 21.0 28.0 35.0 '12.0 19.0 56.0 63.0 70.0 

BILLION BARRELS RECOVERABLE OIL 

~ ASSOCIATED-DISSOLVED GAS 

a 

z 

a: co :X:· 

~CI 

w 

a:::: 

Oco r. a 

~ 

>-<...-

~. 

...... a _] 

-

aJ «:N aJ • oa 

a:::: 

a... a 

d 

"\ ESTIMATES 

MEAN - 39.43 

MEDIAN - 37.41 

\ 95% - 23.29 

75% - 30.75 

50% - 37.41 

\ 25% - 45.82 

5% - 60.76 

MODE - 33.05 

~ S.D. - 12.40 

~ r---

o.o 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.01 

TRILLION CUBIC fEET RECOVERABLE GAS 

TOTAL GAS 

Cl 

z 

~~ ~CI 

w 

a:::: 

Oco 

%: • 

t... 

0 

a 

>-<.,. 

~. 

...... a ...J 

...... 

m «:N m. 

oo 

a:::: 

a... a 

d 

f\ ESTIMATES 

MEAN - 167.01 

MEDIAN - 162.22 

1\ 95% - 117.42 

75% - 141.56 

50% - 162.22 

\ 25% - 187.04 

5% - 230.65 

MODE - 146.92 

S.D • - 36.98 

1\ 

'b::: 

0.0 35.0 70.0 105.0 110.0 175.0 210.0 215.0 280.0 315.0 350.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

a 

z 

a: co :X:· 

~CI 

w 

a:::: 

010 

::E:d 

t... 

0 

>-<..-

!::a 

...J 

-m «:N m. 

oa 

a:::: 

a... a 

d 

~ ESTIMATES 

l\ MEAN - 127.58 

\ MEDIAN - 122.79 

95% - 80.28 

75% - 103.37 

sox - 122.79 \ 25% - 145.57 

1\ 5% - 188.79 

MODE - 114.86 

\ S.D . - 34.84 

~ 1----

o.o 30.0 60.0 90.0 120.0 150.0 180.0 210.0 2i0.0 270.0 300.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

Entire offshore 
-.J 

OIL 

0 

z 

cr ::x:m 

1'-<ci 

t..J 

0:: 

i?~ 

l&... 

c 

0 

~"': -o 

_J 

-

co erN co . co 

0:: 

0.... 

0 

ci 

1\ ESTIMATES 

MEAN - 82.59 

MEDIAN - 81.23 \ 95% - 64.29 

75% - 73.59 

50% - 81.23 

25% - 89.81 

\ 5% - 105.10 

MODE - 79.96 

\ S.D. - 13.45 

\ 

I"--

0.0 20.0 "lO.O 60.0 80.0 100.0 120.0 1"l0.0 160.0 180.0 200.0 

BILLION BARRELS RECOVERABLE OIL 

ASSOCIATED-DISSOLVED GAS 

0 

z 

crm 

:X: • .._..o 

t..J 

0:: 

ceo 

E' 0 

l&... 

c 

~~ 

!::ci 

_J 

co 

Ct::N 

co . co 

0:: 

0.... 

0 

ci 

"I\ ESTIMATES I 

MEAN - 132.98 

\ MEDIAN - 129.67 

95% - 100.99 

75% - 116.87 

50% - 129.67 

1\ 25% - 145. 18: 

5% - MODE - 171.811 123.96 

\ S.D. - 23.52 

I 

L"-r-- I '

o.o 25.0 50.0 75.0 100.0 125.0 150.0 175.0 200.0 225.0 250.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

TOTAL GAS 

0 

z 

cr., 

:X: • f--<0 

t..J 

0:: 

Ceo E. 

0 

l&... 

c 

~~ 

....... 

_o 

_J 

a; 

erN co . co 

0:: 

0.... 0 

ci 

........... 

1\ ESTIMATES 

MEAN - 593.80 

\ MEDIAN - 582.27 

95% - 474.57 

75% - 535.04 

50% - 582.27 

\ 25% - 639.76 

5% - 739.31 

MODE - 577.56 

\ S.D. - 86.75 

I 

~ 1--- I 

0.0 95.0 190.0 285.0 380.0 175.0 570.0 665.0 760.0 855.0 950.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

NON-ASSOCIATED GAS 

0 

z 

crm 

.:c. 

1'-<o 

t..J 

0:: 

Ceo 

E' 

l&... 

c 

0 

~~ ....... 

-o 

.J 

-co erN co . co 

0:: 

0.... •O 

oci 

1\ ESTIMATES 

'MEAN - 460.82 

MEDIAN - 450.00 

~ 95% - 349.98 

75% - 404.01 

50% - 450.00 

~ '25% - 506.17 

5% - 608.71 

·MODE - 451.04 

S.D. - 83.51 

~ 

""' ~""- o.o 80.0 160.0 2"l0.0 320.0 100.0 "l80.0 560.0 610.0 720.0 8~_.0 

TRILLION CUBIC fEET RECOVERABLE GAS 

Entire United States 

APPENDIXES B, C, D, AND E 
-...1 

.... 

, 

The United States has not resolved its 

offshore boundaries with other States concerned. The lines on this chart are for purposes of illustration only, and do not necessarily reflect the position or views of the 

United States with respect to the boundary 

involved. 

0' 

. ,c:,s't>-c, c.-~~, \)-:;>' 

\~01 ;_, ,/ ,, 

16 

f'-,, 

~~..c--...>-...~ 71 "" 

"~ 

' I 

Index map of Alaska showing provinces assessed. Shading denotes offshore shelf areas. Names of onshore provinces are 

listed numerically in Appendix C. Names of offshore provinces are listed numerically by shelf and by slope in Appendix D. 
--.J 

1.11 

Index map of lower 48 States showing provinces assessed. Shading denotes offshore shelf areas. Names of onshore 

provinces are listed numerically in Appendix C. Names of offshore provinces are listed numerically by shelf and by slope in 

Appendix D. 
-.1 

aAppendix C 

Estimates of undiscovered recoverable oil and gas for onshore provinces in the entire United States. 

The following estimates are arranged by Region and province number (see fig. 3 and Appendix B for location). All tabulated values are rounded 

numbers. Negl., negligible, is less than or equal to 0.05 billion barrels of oil or 0.05 trillion cubic feet of gas. S.D., is standard deviation. 

F95 denotes the 95th fractile; the probability of mo~e than the amount F95 is 95 percent. F5 is defined similarly. Fractile values are not additive. 

Region and province Low 

F95 

Region 1 Alaska: 

58 Arctic coastal plain •••••••••••••••••••• 0.9 

59 Northern Foothills...................... .3 

60 Southern Foothills and Brooks Range ••••• 0 

61 Yukon-Porcupine basins •••••••••••••••••• 0 

62 Yukon-Koyukuk basins •••••••••••••••••••• 0 

63 Interior Lowlands ••••••••••••••••••••••• 0 

64 Bristol Basin onshore ••••••.•••••••••••• 0 

65 Hope Basin onshore •••••••••••••••••••••• 0 

66 Copper River basin •••••••••••••••••••••• 0 

67 Cook Inlet onshore...................... .1 

68 Alaska Peninsula •••••••••••••••••••••••• 0 

69 Gulf of Alaska onshore.................. 0 

70 Kodiak Island........................... 0 

71 Southeastern Alaska ••••••••••••••••••••• 0 

Region 

72 

73 

74 

75 

76 

77 

78 

79 

80 

81 

81A 

Region 

82 

83 

84 

85 

86 

87 

88 

89 

90 

91 

92 

93 

Pacific Coast: 

Western Oregon-Washington............... 0 

Sacramento basin •••••••••••••••••••••••• 0 

San Joaquin basin....................... .5 

Los Angeles basin....................... .2 

Ventura basin........................... .2 

Santa Haria basin ••••••••••••••••••••••• Negl. 

Central coastal basins •••••••••••••••••• Negl. 

Sonoma-Livermore basins................. 0 

Humboldt basin.......................... 0 

Eastern Oregon-Washington ••••••••••••••• 0 

Eastern California...................... 0 

Colorado Plateau and Basin and Range: 

Eastern Basin and Range................. 0.2 

Western Bas in and Range. • • • • • • • • • • • • • • • • 0 

Idaho-Snake River downwarp.............. 0 

Paradox basin........................... • 2 

Uinta-Piceance-Eagle basins............. .4 

Park basins ••••••••••••••••••••••••••••• Negl. 

San Juan basin •••••••••••••••••••••••••• Negl. 

Albuquerque-Santa Fe-San Luis 

rift basins........................... 0 

Wyoming-Utah-Idaho overthrust belt •••• ;. 2.7 

Northern Arizona •••••••••••••••••••••••• Negl. 

South-central New Hexico................ 0 

Southern Arizona-southwestern 

New Hexico ••••••••• ,.................. 0 

Crude oil 

(billion barrels) 

High 

F 5 Mean S.D. 

11.6 

3.9 

.9 

0 

0 

I) 

.6 

I) 

• 1 

1.5 

.2 

.8 

I) 

0 

.s 

Negl. 

4.4 

1. 5 

1.2 

• 5 

.4 

Negl. 

0 

3.0 

I) 

11.9 

1.9 

I) 

3.2 

3.8 

.2 

• 4 

.2 

13.3 

1.0 

• 2 

1.3 

4.4 

1.4 

I) 

I) 

I) 

• 1 

0 

Negl • 

.6 

Negl. 

.2 

0 

0 

• 1 

Negl. 

1.8 

.7 

.5 

• 2 

• 2 

Negl. 

I) 

.8 

0 

3. 3 

.4 

I) 

1.2 

1. 6 

• 1 

• 1 

Negl. 

6.7 

• 3 

Negl. 

• 3 

3.9 

1.4 

• 5 

0 

I) 

0 

.2 

0 

Negl. 

• 5 

.1 

0 

0 

• 5 

.2 

Negl. 

1.4 

.4 

• 3 

• 2 

• 2 

Negl. 

() 

1.2 

I) 

6.5 

2.0 

0 

1.1 

1.2 

• 1 

.1 

.l 

3.5 

.6 

.2 

.8 

Associated-dissolved gas 

(trillion cubic feet) 

Low 

F95 

2.4 

0.6 

() 

0 

0 

0 

0 

0 

0 

Negl. 

(I 

0 

0 

0 

0 

Negl. 

• 5 

• 2 

• 3 

Negl. 

Negl. 

0 

0 

0 

0 

0.3 

0 

0 

.4 

.8 

Negl. 

. l 

0 

6.7 

Negl. 

0 

0 

High 

F 5 

30. l 

9.3 

2.4 

0 

0 

0 

I) 

0 

0 

.6 

• 1 

.6 

• 2 

.9 

.4 

.1 

4.4 

1.4 

2. l 

.4 

.2 

Negl. 

0 

4.') 

(I 

17.9 

2.8 

(I 

5.5 

6.5 

.6 

.8 

• 3 

33.3 

1.2 

.4 

1.5 

Mean 

11.4 

3.4 

.4 

0 

0 

0 

• 1 

0 

Negl. 

.2 

Negl. 

0 

() 

• 2 

.l 

Negl. 

1.8 

.6 

1.0 

• 2 

.l 

Negl. 

I) 

1.2 

0 

s.o 

• 6 

0 

2.0 

2.7 

.2 

• 3 

.1 

16.8 

• 3 

.l 

• 3 

S.D. 

10.2 

3.3 

1.4 

0 

0 

0 

() 

0 

I) 

.2 

• 1 

• 2 

• 1 

• 5 

• 2 

Negl. 

1.4 

.4 

• 6 

• 1 

• 1 

Negl. 

0 

1.9 

0 

9.9 

3.6 

0 

1.9 

2.0 

• 3 

• 3 

• 2 

8.7 

• 7 

• 2 

• 9 

Non-associated gas 

(trillion cubic feet) 

Low High 

F95 F5 Mean S.D. 

1.4 

2.6 

0 

0 

u 

0 

0 

I) 

0 

1.1 

0 

0 

0 

I) 

• 5 

• 5 

• 1 

0 

Negl. 

0 

I) 

I) 

Negl. 

1.4 

0 

0 

0 

0 

.3 

1. 4 

0 

.8 

0 

15.6 

0 

0 

0 

17.6 

18.5 

6.9 

0 

.6 

n 

1.7 

0 

• 5 

7.2 

• 7 

.8 

0 

0 

4.8 

3.2 

.8 

• 1 

• 3 

I) 

Negl. 

Negl. 

• 2 

14.4 

0 

21.4 

2.6 

0 

5.1 

15.9 

Negl. 

7.1 

1.2 

85.2 

1.0 

1.1 

8.2 

6.7 

8.3 

1.6 

Negl. 

• 1 

Negl. 

.4 

0 

• 1 

3.3 

• 1 

.1 

0 

0 

1.9 

1.5 

• 3 

Negl. 

• 1 

0 

Negl. 

Negl. 

.1 

5.8 

n 

5.6 

.6 

0 

1.8 

6.2 

Negl. 

3.0 

• 3 

41.6 

.2 

• 3 

2.1 

6.0 

5.4 

3.1 

• 1 

.3 

Negl. 

.8 

0 

• 2 

2. 1 

• 3 

.4 

0 

0 

1.fi 

.9 

• 3 

Negl. 

• 1 

0 

Negl. 

Negl. 

• 1 

4.fi 

0 

10. l 

3.0 

0 

1.9 

5.3 

Negl. 

2.2 

• 6 

23.0 

.6 

• 5 

3.6 
-..J 

-..J 

Region 

94 

95 

96 

97 

98 

99 

100 

101 

102 

103 

104 

lOS 

106 

Region 

107 

108 

109 

110 

111 

Region 

112 

113 

114 

Region 

115 

116 

117 

118 

119 

120 

121 

122 

123 

124 

125 

126 

4 Rocky Mountains and Northern Great Plains: 

Williston basin ••••••••••••••••••••••••• 0.4 

Sioux arch.............................. 0 

Sweetgrass arch......................... .1 

Central Nontana ••••••••••••••••••••••••• Negl. 

Hontana overthrust belt ••••••••••••••••. 0 

Southwestern Nontana •••••••••••••••••••• 0 

Wind River basin........................ .2 

Powder River basin...................... .5 

Southwestern Wyoming basins............. .8 

Big Horn basin.......................... .3 

Denver basin............................ • 2 

Las Animas arch ••••••••••••••••••••••••• Negl. 

Raton Basin-Sierra Grande uplift........ 0 

West Texas and ea:;tern New Nexico: 

Permian basin ••••••••••••••••••••••••••• 

Palo Duro basin ••••••••••••••••••••••••• 

Pedernal uplift ••••••••••••••••••••••••• 

Bend Arch-Fort Worth basin •••••••••••••• 

1.0 

Negl. 

II 

• 7 

Marathon fold belt •••••••••••••••••••••• Negl. 

Gulf Coast: 

\~estern Gulf basin •••••••••••••••••••••• 

East Texas basin •••••••••••••••••••••••• 

Louisiana-}!issis:;ippi salt basins ••••••• 

:lid-continent: 

1.2 

• 3 

.8 

Anadarko ba:;in.......................... • 7 

Arkoma basin •••••••••••••••••••••••••••• Negl. 

Cambridge Arch-central Kan:;as uplift. •••• 1 

Cherokee platform ••••••.•••••••••••••••• 

Forest City basin •..••••••••••••.••••••• 

Nemaha ridge •••••••.•••..••••••••••••..• 

Salina basin •••••• ' ••.••.•••.•••••••••••• 

Sedgwick basin ••.••••••••••••••••••.•••• 

Southern Oklahoma ••••••••••••••••••••••• 

Sioux uplift •••••••••••••.••..••••••.••• 

Iowa shelf ••.••••••••••••••••••••••••••• 

Ozark uplift •.•••••••••••••••..•••.••.•• 

Negl. 

Negl. 

Negl. 

() 

.1 

• 2 

() 

0 

II 

Region 8 ~lichigan basin: 

127 Hichigan basin ••••••••••••••••••••••.••• • 3 

Region Eastern Interior: 

128 

129 

130 

Illinois basin.......................... .1 

Cincinnati Arch •••••••.••••••.•••••••••• Negl. 

Black Warrior basin •••••••••••••••.••••• Negl. 

Region 10 Appalachians: 

131 .\ppalachian basin....................... .1 

132 !Hue Ridge overthrust belt.............. I) 

133 Piedmont................................ 0 

134 New England-Adirond:~ck.................. 0 

Region 11 Atlantic Cnast: 

135 Atlantic cnastal plain •••••••••••••••••• II 

136 Florida Peninsul:J........................ .1 

3.2 

() 

1.2 

.4 

2.0 

• 6 

1.4 

2.8 

6.0 

2.3 

1.8 

• 3 

• 6 

6.2 

• 1 

0 

4.2 

1.7 

8.0 

2.7 

5.0 

5. 1 

1.0 

1.0 

1.0 

.1 

• 2 

Negl. 

.6 

1. 8 

() 

u 

I) 

2.7 

1.4 

• 5 

• 5 

l. 5 

I) 

0 

0 

0 

• 8 

1.4 

0 

.4 

• 2 

.6 

.2 

• 6 

1.4 

2.6 

1.0 

.8 

.1 

• 2 

2.9 

Negl. 

I) 

2.0 

.s 

3.6 

1.2 

2.3 

2.2 

• 3 

.4 

• 3 

Negl. 

.1 

Negl. 

.2 

.7 

0 

0 

0 

1.1 

11 

• 6 

.2 

.2 

.6 

• 3 

0.9 

0 

.4 

• 1 

• 9 

• 3 

.4 

.8 

1.8 

• 7 

• 6 

.1 

.4 

1.7 

Negl. 

0 

1.2 

.8 

2.3 

.8 

1.4 

1.5 

.4 

• 3 

.4 

Negl. 

.1 

Negl. 

.2 

.6 

() 

() 

0 

0 

0 

0 

() 

.8 

.4 

• 2 

• 3 

• 5 

• 3 

0.8 

0 

Negl. 

Negl. 

() 

0 

0 

0 

.1 

.8 

.9 

• 2 

• 2 

2.1 

I) 

0 

1.3 

Negl. 

J.O 

• 2 

• 6 

1.6 

• 1 

• 1 

.1 

Negl. 

Negl. 

I) 

Negl. 

• 4 

() 

0 

0 

• 4 

• 1 

Negl. 

Negl. 

• 1 

n 

Negl. 

5.8 

0 

.4 

.2 

4.4 

• 9 

• 7 

4.2 

6.5 

1.6 

1.8 

Negl. 

• 6 

12.9 

Negl. 

() 

7.5 

1.3 

20.0 

1.9 

4.0 

11.9 

2.3 

.7 

2.2 

• 1 

.1 

Negl. 

.4 

4.2 

0 

I) 

I) 

3.2 

.6 

• 2 

.8 

1.2 

() 

I) 

0 

I) 

• 1 

2.6 

0 

• 2 

• 1 

1.3 

• 2 

.3 

2.1 

2.9 

.7 

.8 

Negl. 

• 2 

6.0 

Negl. 

0 

3.6 

.4 

9. 1 

.8 

1.9 

5.2 

• 7 

• 3 

.8 

Negl. 

.1 

Negl. 

• 2 

1.6 

0 

0 

II 

1.4 

• 2 

• 1 

• 2 

• 5 

0 

0 

() 

I) 

Negl • 

1.7 

0 

.1 

Negl. 

1.9 

.4 

• 2 

1.1 

1.9 

.s 

.6 

Negl. 

.4 

3.6 

Negl. 

0 

2. 1 

• 6 

5.8 

.6 

1.1 

3.5 

1.0 

.2 

.8 

Negl. 

Negl. 

Negl. 

• 1 

1.4 

I) 

I) 

0 

1.0 

0 

I) 

0 

• 2 

.1 

.4 

.4 

0 

Negl. 

0.2 

0 

.6 

.1 

1.8 

0 

• 7 

.1 

5.3 

• 6 

• 5 

• 3 

Negl. 

9.0 

Negl. 

0 

1.9 

() 

27.8 

2.2 

3.5 

10.2 

• 5 

• 2 

Negl. 

Negl. 

Negl. 

u 

() 

I) 

0 

.2 

.4 

.9 

Negl. 

.1 

.4 

5.4 

0 

0 

0 

I) 

0 

1.7 

0 

6.5 

1.6 

20.6 

.7 

4.2 

1.2 

33.7 

3.7 

3. 1 

2.3 

1.1 

59.7 

.4 

I) 

9.0 

2.9 

209.3 

13.7 

34.9 

63. 1 

8. 1 

• 9 

1.2 

Negl. 

• 6 

(I 

1.3 

4.6 

0 

0 

0 

9.3 

1.5 

1.7 

2.6 

43.2 

5.0 

0 

0 

• 3 

0 

0.8 

0 

2.6 

• 5 

8.0 

• 2 

2.0 

.4 

15.7 

1.7 

1.4 

1.0 

.4 

27.3 

• 1 

0 

4.6 

• 7 

92.1 

6.4 

14. 1 

29.5 

2.8 

.4 

• 3 

Negl. 

.2 

0 

.6 

1. 8 

0 

0 

() 

3.8 

.4 

• 6 

1.2 

18.6 

1. 1 

0 

0 

• 1 

0 

0.5 

0 

2. 1 

.6 

6.8 

• 3 

1.2 

• 5 

9.6 

1.0 

• 9 

.7 

• 5 

17.0 

• 2 

0 

2.3 

1.5 

62.2 

3.8 

11. 1 

17.6 

3.0 

• 3 

.6 

Negl. 

.4 

0 

.4 

1.5 

0 

0 

(} 

3.0 

• 7 

• 6 

.8 

13.0 

2.1 

0 

II 

• 3 

0 
-.1 

00 

Appendix D 

Estimates of undiscovered recoverable oil and gas for offshore provinces in the entire United States. 

The following estimates are arranged by shelf and slope; within these two categories the Regions and provinces are listed by number (see fig. 3 

and Appendix B for location). All tabulated values are rounded numbers. Negl., negligible, is less than or equal to 0.05 billion barrels of oil or 

0.05 trillion cubic feet of gas. S.D. is standard deviation. F95 denotes the 95th fractile; the probability of moPe than the amount F95 is 95 

percent. F5 is defined similarly. Fractile values are not additive. 

Crude oil Associated-dissolved gas Non-associated gas 

(billion barrels) (trillion cubic feet) (trillion cubic feet) 

Region and province Low High Low High Lqw High 

F95 F5 Mean S.D. F95 F5 Mean S.D. F95 F5 Mean S.D. 

Shelf (0-200 meters water depth) 

Region 1A Alas~a: 

1 Beaufort •••• f ••••••••••••••••••••••• 1.9 16.7 7.0 5.2 3.0 26.8 11. 1 8.4 6.4 58.5 23.9 18.5 

3 North Chukchi ••••••••••••••••••••••• 0 4.2 .8 1.8 0 6.3 1.2 2.6 0 11.4 2.2 4.7 

5 Central Chukchi 1 ••••••••••••••••••••• 0 3.3 .6 1.5 0 4.9 .9 2.2 0 10.4 2. 1 4.2 

6 Hope 1 •••••••••••••••••••••••••••••••• u .1 Negl. • 1 0 .2 Negl. • 2 0 1.6 .3 .9 

8 Norton ••••••••••••••••••••••••••••••• 0 .9 .2 • 5 0 1.4 .2 .8 0 4.1 1.0 1.7 

9 Bristol •••••••••••••••••••••••• • • • • •• Q 1.2 • 2 .6 0 1.9 • 3 1.0 0 3.7 .7 1.9 

10 Navarin basin •••••••••••••••••••••••• 0 3.7 .8 2.2 0 5.5 1.2 3.3 0 16.6 4.0 6.8 

12 St. George basin •••••••••••••••••••• () 2.2 .4 1.1 0 3.3 .6 1.6 0 7.4 1.7 2.8 

13 Zhemchug ••••••••••••••••••••••••••••• 0 • 2 Negl. • 2 0 .3 Negl. • 3 0 .7 • 1 .4 

15 St. Matthew-Hall ••••••••••••••••••••• 0 0 0 0 0 0 0 0 0 0 0 0 

16 Aleutian ••••••••••••••••••••••••••••• 0 0 0 0 0 0 0 0 0 0 0 0 

18 Kodiak ••••••••••••••••••••••••••••••• 0 1.0 .2 .5 0 1.7 • 3 .9 0 5.2 1.0 2.3 

20 Shumagin ••••••••••••••••••••••••••••• 0 .2 Negl. • 2 0 • 3 • 1 .3 0 1.6 .2 • 7 

22 Gulf of Alaska ••••••••••••••••••••••• 0 1. 5 • 3 • 7 0 2.2 .4 1.0 0 5.9 1.3 2.6 

24 Cook Inlet ••••••••••••••••••••••••••• • 1 1.0 .4 .4 Negl. .6 .2 .2 .7 4.6 2.0 1.4 

25 Shelikof Strait shallow •••••••••••••• 0 • 2 Negl. .2 0 • 1 Negl. .1 0 .7 • 1 .4 

Region 2A Pacific Coast: 

27 Inner basins shallow ••••••••••••••••• • 1 .9 .4 .3 • 1 .8 .3 • 3 0 0 0 0 

29 Outer basins and ridges shallow •••••• 0 • 1 Negl. Negl. 0 .1 Negl. • 1 0 0 0 0 

31 Santa Barbara Channel •••••••••••••••• .1 1.6 .6 .6 • 1 1. 4 .5 .5 .1 1.7 .5 .8 

33 Santa Maria •••••••••••••••••••••••••• 0 .8 • 2 • 3 0 • 7 .2 .3 0 0 0 0 

35 Santa Cruz ••••••••••••••••••••••••••• 0 .6 • 1 .2 0 .5 • 1 .2 0 0 0 0 

37 Bodega ••••••••••••••••••••••••••••••• 0 .2 Negl. • 1 0 .2 Negl. .1 0 0 0 0 

39 Point Arena •••••••••••••••••••••••••• 0 .2 Negl. • 1 0 .2 Negl. .1 0 0 0 0 

41 Eel River •••••••••••••••••••••••••••• 0 • 2 Negl. • 1 .0 • 2 Negl. .1 0 .9 • 2 .3 

43 Oregon-Washington •••••••••••••••••••• 0 .6 • 1 .4 0 .7 • 1 .4 0 2. 1 • 5 .9 

Region 6A Gulf of Mexico: 

45 Eastern Gulf ••••••••••••••••••••••••• 0 3.8 1.2 1.4 0 3. 1 .9 1.2 0 5.9 1.5 2.3 

47 Western Gulf •••••••• ••••••••••••••••• 1.1 5.7 2.8 1.5 1.8 9.6 4.8 2.6 16.3 72.6 38.1 18.1 

Region 11A Atlantic Coast: 

49 North Atlantic ••••••••••••••••••••••• 0 2. 1 .4 .9 0 2.5 .6 1.1 0 7.2 1.9 2.9 

51 Mid-Atlantic ••••••••••••••••••••••••• 0 2.6 .8 1.0 0 3.2 .9 1.2 0 11.6 4.7 3.8 

53 South Atlantic ••••••••••••••••••••••• 0 .3 Negl. .2 0 .3 Negl. .2 0 .7 • 1 .3 

56 Southeast Florida •••••••••••••••••••• 0 0 0 0 0 0 0 0 0 0 0 0 
-J 

...0 

Region lA Alasfa: 

2 Beaufort •••• 1 ...................... . 4 North Chukchi ••••••••••••••••••••••• 

7 Umnak Plateau •••••••••••••••••••••••• 

11 Navarin basin •••••••••••••••••••••••• 

14 Zhemchug ••••••••••••••••••••••••••••• 

17 Aleutian ••••••••••••••••••••••••••••• 

19 Kodiak •••••••••• •••••• ••••••••••••••• 

21 Shumagin ••••••••••••••••••••••••••••• 

23 Gulf of Alaska ••••••••••••••••••••••• 

26 Shelikof Strait deep ••••••••••••••••• 

Region 

28 

30 

32 

34 

36 

38 

40 

42 

44 

2A Pacific Coast: 

Inner basins deep •••••••••••••••••••• 

Outer basins and ridges deep ••••••••• 

Santa Barbara Channel deep ••••••••••• 

Santa Maria •••••••••••••••••••••••••• 

Sa.nta Cruz ••••••••••••••••••••••••••• 

Bodega ••••••••••••••••••••••••••••••• 

Point Arena •••••••••••••••••••••••••• 

Eel River •••••••••••••••••••••••••••• 

Oregon-Washington •••••••••••••••••••• 

Region 6A Gulf of Mexico: 

46 Eastern Gulf ••••••••••••••••••••••••• 

48 Western Gulf ••••••••••••••••••••••••• 

Region llA Atlantic Coast: 

50 North Atlantic ••••••••••••••••••••••• 

52 Mid-Atlantic ••••••••••••••••••••••••• 

54 Carolina trough •••••••••••••••••••••• 

55 Blake Plateau •••••••••••••••••••••••• 

57 Florida Straits •••••••••••••••••••••• 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

.1 

0 

0 

0 

0 

0 

0 

0 

.9 

0 

0 

0 

0 

0 

Slope (200-2,500 meters water depth) 

3.6 

1. 1 

0 

.6 

0 

0 

1.0 

.2 

.7 

0 

1.0 

2.5 

2. 1 

2.2 

.5 

.2 

.4 

.2 

1.3 

1.0 

4.8 

3.8 

7.6 

3.0 

1.7 

0 

0.8 

.2 

0 

• 1 

0 

0 

.2 

Negl. 

.1 

Negl. 

.2 

.5 

• 7 

.5 

• 1 

Negl. 

• 1 

Negl. 

.2 

.2 

2.4 

1.0 

2.3 

.6 

.3 

0 

2.0 

.6 

0 

• 3 

0 

0 

.8 

.2 

.4 

Negl. 

• 5 

1.1 

.8 

1.1 

• 3 

• 1 

.2 

.2 

.6 

.4 

1.3 

1.6 

2.8 

1.4 

.7 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

• 1 

0 

0 

0 

0 

0 

0 

0 

1.6 

0 

0 

0 

0 

0 

5.7 

1.7 

0 

1.0 

0 

0 

1.8 

• 3 

1.0 

0 

.9 

3.7 

2.5 

2.0 

.4 

• 1 

.3 

• 3 

1.6 

.8 

8.7 

4.6 

9.1 

3.3 

1.7 

0 

1.2 3.2 

• 3 .9 

0 0 

.1 .4 

0 0 

0 0 

.3 1.4 

.1 .4 .2 • 6 

Negl. Negl. 

.2 

.8 

.8 

.4 

• 1 

Negl. 

Negl. 

Negl. 

• 3 

• 2 

4.2 

1.1 

2.7 

• 7 

• 3 

0 

• 5 

1.7 

1.0 

1.0 

.3 

.1 

• 2 

• 2 

• 7 

• 3 

2.4 

1.9 

3.4 

1.6 

.7 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

7.2 

0 

0 

0 

0 

0 

12. 1 

3.2 

0 

1.8 

0 

0 

2. 1 

1.6 

1.7 

0 

0 

.7 

1.9 

0 

0 

0 

0 

1.2 

3.0 

1.8 

47.6 

7.9 

17.8 

9.6 

2.4 

0 

1Estimated quantities for these provinces can be considered recoverable only if technology permits their exploitation beneath 

Arctic pack ice--a condition not yet met. 

3. 1 

.8 

0 

• 3 

0 

0 

.4 

• 2 

• 3 

Negl. 

0 

• 1 

• 7 

0 

0 

0 

0 

.3 

.6 

• 3 

21.9 

2. 1 

5.9 

2. 1 

.4 

0 

11. 1 

3.3 

0 

.8 

0 

0 

1.2 

.8 

.8 

Negl. 

0 

0 

0 

0 

0 

• 5 

.8 

• 5 

1.4 

.8 

13.6 

3.3 

6.5 

4.5 

1.3 

0 
Appendix E 

Estimated Federal ownership of oil and gas resources 

The percent of undiscovered recoverable oil and gas resources listed 

below are for those resources estimated to occur offshore under Federal 

waters and onshore on non-Indian Federal lands and on patented lands with 

Federally reserved oil and gas rights. Alaska is not included because land 

ownership there has not been completely determined. All values are rounded 

to the nearest 5 percent. Negl., negligible, is less than 2.5 percent. 

Region 

Offshore (0-2500 m): 

2A Pacific Coast ••••••••••••••••••••••••• 

6A Gulf of Mexico •••••••••••••••••••••••• 

llA Atlantic Coast •••••••••••••••••••••••• 

Entire Lower 48 States offshore •••••••••••• 

Onshore: 

2 

3 

4 

5 

6 

Pacific Coast •••••••••••••••••••••••••• 

Colorado Plateau and 

Basin and Range •••••••••••••••••••••• 

Rocky Mountains and 

northern Great Plains •••••••••••••••• 

West Texas and eastern 

New Mexico ••••••••••••••••••••••••••• 

Gulf Coast ••••••••••••••••••••••••••••• 

7 Mid-continent •••••••••••••••••••••••••• 

8 Michigan Basin •••••••••••••••••••••••• 

9 Eastern Interior ••••••••••••••••••••••• 

10 Appalachians ••••••••••••••••••••••••••• 

11 Atlantic Coast •••••••••••••••••••••••• 

Lower 48 States onshore ••••••••••••••••••• 

1Percent of mean resource estimate. 

80 

Percent Federal ownership 1 

Oil Gas 

85 90 

95 95 

100 100 

95 95 

10 25 

70 70 

50 55 

5 5 

Negl. Negl. 

Negl. Negl. 

5 5 

Negl. Negl. 

5 5 

10 5 

30 25 
APPENDIX F 

Estimation of inferred plus indicated reserves for the United States, 

By D. H. Root 
ILLUSTRATIONS 

Figures Fl-F4.--Graphs showing: 

Fl.--Projected total growth of estimates of the amount 

of ultimately recoverable crude oil in fields 

discovered before 1979 in the conterminous 

United States versus the number of years of 

Page 

data used............................................. 83 

F2.--The growth of estimates of the amount of recoverable 

oil discovered in a given year in the conterminous 

United States versus the number of years after the 

year of discovery..................................... 84 

F3.--The growth of estimates of the amount of recoverable 

natural gas discovered in a given year in the 

conterminous United States versus the number of 

years after the year of discovery..................... 84 

F4.--Projected total growth in estimates of the amount 

of ultimately recoverable natural gas in fields 

discovered before 1979 in the conterminous 

United States versus the number of years of 

data used............................................. 87 

TABLES 

Table Fl.--Estimated inferred plus indicated reserves of crude oil 

in fields discovered in the United States exclusive of 

Alaska as of Dec. 31, 1978 ••• ••••••••••• ••••••• ••• •••••• •• • 85 

F2.--Estimated inferred reserves of natural gas in fields 

discovered in the United States exclusive of Alaska as of 

Dec. 31, 1978.............................................. 86 

82 
Estimation of Inferred Plus Indicated Reserves for the United States 

By D. H. Root 

Estimates of the amounts of crude oil and 

natural gas discovered in the United States and 

Canada are published by the American Petroleum 

Institute, the American Gas Association and the 

Canadian Petroleum Association (API, AGA, and 

CPA). These estimates have been updated 

annually since 1967 (API and others, 1967-

1979). Ultimate recovery (defined as past 

production plus proved reserves) of oil or gas 

in fields discovered in a given year usually 

increases from one estimate to the next. 

Increases are proportionately larger for younger 

discoveries than for older discoveries. 

The changes in estimates of the amounts of 

oil and gas discovered in a given year could be 

due to several reasons: (1) drilling could 

prove that some fields were larger or smaller 

than had been thought, (2) production experience 

could indicate that the assumed recovery factors 

were too high or too low, ( 3) application of 

improved recovery techniques could change the 

anticipated crude-oil recovery, (4) a field 

could be reported to the reserves committee for 

the first time several years after its 

discovery, (5) the discovery year assigned to a 

field could be changed which would shift the 

estimate of the field's oil or gas to another 

discovery year, and (6) new producing zones 

could be found in an old field. 

The phenomenon of growth in estimates of 

the amount of oil and gas has been studied by 

many authors (Arrington, 1960; Hubbert, 1974; 

Marsh, 1971; Mast and Dingler, 1975; Pelto, 

1973; and White and others, 1975) in an effort 

to estimate what future increases could be 

expected. Methods and data used by those 

authors to estimate future additions to proved 

reserves from growth of past discoveries are 

similar to those used here. 

The future growth of estimates of ultimate 

recovery from fields discovered before 1979 is 

estimated here under the assumptions that ( 1) 

when a field has been known for 59 years, its 

estimated ultimate recovery will no longer 

change, and (2) estimates of recoverable oil and 

gas in recently discovered fields will show the 

same percentage growth with similar age as do 

estimates for fields that were discovered years 

ago. Annual data (API and others, 1967-1979) go 

back only to 1920; hence, the choice of 59 years 

83 

in assumption "1." Although this petroleum data 

series began in 1967 (API and others, 1967), 

only those books for the years 1971 through 1978 

were used to estimate growth factors for 

recoverable oil. The length of the data series 

used has an effect on the estimated future 

growth. Figure F1 shows how varying the number 

of years of data changes the estimated future 

additions to reserves from pre-1979 fields. Use 

of 1971 through 1978 data gives an average 

amount of growth. 

The growth remaining in the fields 

discovered in a given year is calculated by 

estimating the expected percentage growth for 

each year of aging until the fields become 59 

years old and then accumulating the 1-year 

growth factors. The- calculation of the amount 

of growth from the first to the second estimate 

serves as an example. Several estimates of 

ultimate recovery are available for oil fields 

discovered in the years 1971 through 1977; they 

C/) 40 ....J 

w 

a: 35 a: 

<( 

al 30 z 

0 25 ::::::; 

....J 

iii 20 

"' 

~ 15 

~ 

::i 10 ~ 

~ 5 0 

a: 

(!) 0 

13 12 11 10 9 8 7 6 5 4 3 2 

NUMBER OF YEARS OF DATA 

Figure Fl.--Projected total growth of estimates 

of the amount of ultimately 

recoverable crude oil in fields 

discovered before 1979 in the 

conterminous United States versus 

the number of years of data used. 

Thirteen years of data are from 

1966 to 1978; two years of data are 

from 1977 to 1978 (American 

Petroleum Institute and others 

1967-1979). 
include estimates made at the end of the year of 

their discovery and estimates made 1 year after 

that. From these estimates, the expected 

percentage increase between the first and second 

estimate can be calculated. Let w(i,j) be the 

estimate as of the end of year j of recoverable 

oil in all fields discovered during year i. The 

estimated 1-year growth factor from the first to 

the second estimate is then given by the ratio 

1977 

~ w(i ,i+l) 

i 1971 r(l) (1) 

1977 

~ w( i, i) 

i 1971 

In general, the estimated 1-year growth 

factor from the n-1 year estimate to the nth 

year estimate is given by 

i 

i 

1978-n 

~ w(i, i+n) 

max of 1972-n, 1919 

1978-n 

~ w(i, i+n-1) 

max of 1972-n, 1919 

r(n) (2) 

For the purposes of these calculations, all 

fields discovered before 1920 were credited to 

1919. The amount by which the estimate of the 

recoverable oil discovered in the conterminous 

United States in a given year is expected to 

increase is obtained by multiplying the 1978 

estimated ultimate recovery estimate by all the 

r(n) from equation (2) where n is greater than 

the difference between 1978 and the discovery 

year and is less than 60. The growth factor for 

an estimate as of Dec. 31, 1978 of recoverable 

o~~~~~~~~~~~~~~~~~~~~~ 

0 5 1 0 1 5 20 25 30 35 40 45 

YEARS AFTER DISCOVERY 

50 55 60 

Figure F2.--The growth of estimates of the 

amount of recoverable oil 

discovered in a given year in the 

conterminous United States versus 

the number of years after the year 

of discovery. Data from the 

American Petroleum Institute and 

others (1972-1979, v. 26 through 

33). 

84 

oil in fields discovered n-1 years ago as of 

Dec. 31, 1978 is given by R(n), the product of 

all the 1-year growth factors, r( i) where i is 

greater than n-1. 

59 

R(n) =1Tr(i) (3) 

i=n 

Figure F2 shows how the estimate of recoverable 

oil discovered in a given year in the 

conterminous United States is projected to 

increase from its first estimate to its fiftyninth estimate. Similar growth curves can be 

calculated for individual reporting areas. The 

estimated known ultimate production from known 

oil fields (including growth) was calculated by 

applying the growth factors for each reporting 

area to the corresponding oil-discovery data. 

The estimated inferred and indicated reserves 

are derived from these figures by subtraction of 

API cumulative production and proved reserves. 

The results of the individual State calculations 

are presented in table Fl. Note that the sum of 

the State estimates differs somewhat from the 

estimate calculated for the conterminous United 

States as a whole. 

The American Gas Association estimates of 

the amount of natural gas discovered in the 

United States are divided by geographic 

location, year of discovery, and whether the gas 

is associated with crude oil or not (API and 

others, 1967-1979). Growth factors for natural 

gas were calculated in the same manner as for 

oil. In addition to the growth factors 

calculated for total natural gas (fig. F3), 

individual growth factors for associated and 

non-associated natural gas also were 

calculated. Calculations indicated that most of 

the growth in natural gas is expected to be in 

non-associated gas; not much growth in 

associated gas. Because trends in natural gas 

w 

..... 

<( 

:iE 

i= 

!J) 

w 

...J 

<( 

~ 

(!) 

a: 

0 

u.. 

0 

w 

...J 

a.. 

i= 

...J 

:::::> 

:iE 

3 

2 

0 ~~~~~~~~~~~~~~~~~~~~~~~ 

0 5 1 0 15 20 25 30 35 40 45 50 55 60 

YEARS AFTER DISCOVERY 

Figure F3.--The growth of estimates of the 

amount of recoverable natural gas 

discoverd in a given year in the 

conterminous United States versus 

the number of years after the year 

of discovery. Data from the 

American Petroleum Institute and 

others (1971-1979, v. 25 through 

33). 
Table F-1.--Gstimated infePPed plus indicated pesepves of cPude oil in fields discovePed 

in the United States exclusive of Alaska as of Dec. 31~ 19?8 

[Tabulated values are compiled from American Petroleum Institute data (American Petroleum 

Institute and others, 1967-1979). Values shown are in thousand barrels. Asterisk, 

*, indicates that the offshore is included] 

Estimated ultimate 

production 

from known fields 

Reporting area (including growth) 1 

Alabama.................... 289,977 

Arkansas................... 1,701,211 

California: 

*Coastal •••••••••••••.•• 

*Los Angeles basin •••••• 

*San Joaquin basin •••••• 

Colorado ••••••••••••••••••• 

Illinois ••••••••••••••••.•• 

Indiana •••••••••••••••••••• 

Kansas ••••••••••••••••••••• 

Kentucky, Ohio, 

Pa., W.Va ••••••••••••••• 

Louisiana: 

North ••••••••••••••••••• 

*South ••••••••••••••••••• 

Michigan ••••••••••••••••••• 

Mississippi •••••••••••••••• 

Montana •••••••••••••••••••• 

Nebraska ••••••••••••••••••• 

New Mexico: 

Northwest ••••••••••••.•• 

Southeast ••••••••••••.•• 

North Dakota ••••••••••••••• 

Oklahoma ••••••••••••••••••• 

Texas districts: 

RR1 ••••••••••••••••••••• 

*RR2 ••••••••••••••••••••• 

*RR3 ••••••••••••••••••••• 

*RR4 ••••••.•••••••••••••• 

RRS ••••••••••••••••••••• 

RR6 ••••••••••••••••••.•• 

RR7B •••••••••••••••••••• 

RR7C •••••••••••••••••••• 

RR8 •••••.••••••••••••••• 

RR8A •••••••••••••••••••• 

RR9 and 10 •••••••••••••• 

Utah and Wyoming ••••••••••• 

Miscellaneous 1 ••••••••••••• 

Total United States 

exclusive of Alaska ••••• 

Gulf of Mexico 2 •••••••••••• 

5,678,865 

8,131,261 

11,161,506 

1,704,301 

3,267,886 

548,932 

5,710,048 

3,640,751 

2,482,399 

20,997,900 

1, 782,923 

2,150,088 

1,439,195 

423,121 

266,112 

5,355,099 

905,445 

13,749,133 

1,274,930 

2,554,210 

7,640,943 

3,079,096 

977,621 

8,247,950 

2,229,344 

1,655,041 

13,251,172 

10,093,575 

4,914,207 

9,105,129 

1,377,139 

157,786,510 

8,168,899 

Cumulative 

production 

200,747 

1,446,573 

3,156,060 

7,152,843 

7,789,342 

1,230,506 

3,100,162 

464,690 

4,789,712 

3,305,658 

1,981,695 

13,874,593 

769,008 

1,636,855 

987,950 

370,871 

171,722 

3,223,574 

524,969 

11,598,031 

785,812 

2,172,047 

6,811,104 

2,934,220 

923,298 

6,584,387 

1,665,402 

1,434,728 

9,111,527 

6,196,870 

4,385,534 

5,074,035 

551,344 

116,405,869 

5,299,088 

Proved 

reserves 

33,107 

94,038 

601,756 

879,222 

1,990,323 

198,012 

137,927 

26,515 

350,367 

240,858 

208,742 

2,684,659 

190,164 

187,587 

140,466 

29,291 

16,826 

468,814 

161,213 

1,073,469 

110,258 

382,189 

745,558 

122,586 

54,323 

1,512,934 

188,922 

166,334 

2,389,899 

1,694,063 

322,925 

959,938 

193,119 

18,556,404 

1,749,464 

Estimated inferred 

plus indicated 

reserves 

56,123 

160,600 

1,921,049 

99,196 

1,381,841 

275,783 

29,797 

57,727 

569,969 

94,235 

291,962 

4,438,648 

823,751 

325,646 

310,779 

22,959 

77 '564 

1,662,711 

219,263 

1,077,633 

378,860 

0 

84,281 

22,290 

0 

150,629 

375,020 

53,979 

1,749,746 

2,202,642 

205,748 

3,071,156 

632,676 

22,824,237 

1,120,347 

1Miscellaneous includes: Arizona, Florida, Missouri, Nevada, New York, South Dakota, 

Tennesse, Virginia, and Washington. 

2Gulf of Mexico offshore is included in Texas and Louisiana above, but is also listed 

as separate entry here to be consistent with American Petroleum Institute practice. 

85 
Table F-2.--Estimated infePPed PesePVes of natuPal gas in fields discovePed 

in the United States exclusive of Alaska as of Dec. 31, 19?8 

[Tabulated values are compiled from American Gas Association data (American 

Petroleum Institute and others, 1967-1979). Values shown are in million cubic feet. 

Asterisk, *, indicates that the offshore is included] 

Reporting area 

Alabama ••••••••••••••••••• 

Arkansas •••••••••••••••••• 

California: 

*Coastal ••••••••••••••• 

*Los Angeles basin ••••• 

San Joaquin basin ••••• 

Colorado •••••••••••••••••• 

Kansas •••••••••••••••••••• 

Kentucky •••••••••••••••••• 

Louisiana: 

North ••••••••••••••••• 

*South ••••••••••••••••• 

Michigan •••••••••••••••••• 

Mississippi ••••••••••••••• 

Montana ••••••••••••••••••• 

New Mexico: 

Northwest ••••••••••••• 

Southeast ••••••••••••• 

New York •••••••••••••••••• 

North Dakota •••••••••••••• 

Ohio •••••••••••••••••••••• 

Oklahoma •••••••••••••••••• 

Pennsylvania •••••••••••••• 

Texas districts: 

RR1 ••••••••••••••••••• 

*RR2 ••••••••••••••••••• 

*RR3 ••••••••••••••••••• 

*RR4 ••••••••••••••••••• 

RRS ••••••••••••••••••• 

RR6 ••••••••••••••••••• 

RR7B •••••••••••••••••• 

RR7C •••••••••••••••••• 

RR8 ••••••••••••••••••• 

RR8A •••••••••••••••••• 

RR9 ••••••••••••••••••• 

RR1 0 •••••••••••••••••• 

Utah •••••••••••••••••••••• 

Virginia •••••••••••••••••• 

Wyoming ••••••••••••••••••• 

West Virginia1 •••••••••••• 

Miscellaneous •••••••••••• 

Estimated ultimate 

production 

from known fields 

(including growth) 1 

1,316,002 

6,122,064 

6,379,027 

7,695,404 

23,484,657 

6,405,314 

40,041,628 

4,612,374 

28,098,933 

210,352,586 

3,311,682 

8,183,810 

3,061,443 

23,569,883 

25,633,059 

817,645 

1,656,389 

7,401,222 

70,646,599 

11,941,277 

4, 910,716 

29,145,776 

64,459,134 

59,874,283 

3,924,810 

24,482,339 

6,615,519 

9,338,267 

46,860,926 

7,519,520 

6,360,188 

57,966,492 

2,613,725 

232,347 

15,649,368 

18,803,430 

3,025,407 

Total United States exclusive 

of Alaska •• ~··••••••••• 

Gulf of Mexico ••••••••••• 

852,513,245 

112,074,200 

Cumulative 

production 

204,468 

3,398,326 

4,879,920 

6,992,565 

16,306,916 

3,249,739 

25,089,559 

3,370,691 

22,536,432 

122,196,727 

1,090,611 

5,290,880 

1,713,400 

11,235,671 

17,973,482 

564,978 

832,045 

5,502,148 

49,145,070 

9,203,489 

2,831,532 

20,258,807 

39,286,732 

39,109,643 

2,606,787 

16,617,900 

4,793,943 

5,866,211 

30,194,839 

5,255,155 

4,378,382 

47,713,768 

1,380,774 

99,056 

8,195,597 

15,060,994 

2,321,781 

556,749,018 

49,744,133 

Proved 

reserves 

751,219 

1,601,544 

643,020 

258,729 

3,819,537 

1,930,275 

12,175,595 

583,199 

2,164,930 

47,188,603 

1,169,746 

1,319,244 

834,462 

9,641,299 

3,592,202 

150,213 

411,485 

1,177,511 

11,205,421 

1,511,256 

1,067,071 

4,325,822 

13,178,205 

10,527,441 

658,827 

4,220,103 

836,029 

1,677,331 

8,294,307 

1,075,564 

976,416 

7,510,570 

696,557 

79,064 

4,262,841 

2,301,271 

223,741 

164,040,650 

35,635,006 

Estimated 

inferred 

reserves 

360,315 

1,122,194 

856,087 

444,110 

3,358,204 

1,225,300 

2, 776,474 

658,484 

3,397,571 

40,967,256 

1,051,325 

1,573,686 

513,581 

2,692,913 

4,067,375 

102,454 

412,859 

721,563 

10,296,108 

1,226,532 

1,012,113 

4,561,147 

11,994,197 

10,237,199 

659,196 

3,644,336 

985,547 

1,794,725 

8,371,780 

1,188,801 

1,005,390 

2,742,154 

536,394 

54,227 

3,190,930. 

1,441,165 

479,885 

131,723,577 

26,695,061 

1

Miscellaneous includes: Arizona, Florida, Illinois, Missouri, Nebraska, 

South Dakota, Tennessee, and Washington. 

2

Gulf of Mexico offshore is included in Texas and Louisiana above, but is 

also listed as a separate entry here to be consistent with American Petroleum 

Institute practice. 

86 
1-

w 

w 

LL. 

u 

iii 

::> 

u 

N 

0 

~ 

r.· 

1-

~ 

0 

a: 

(!) 

'160 

140 

120 

100 

80 

60 

40 

20 

0 13 12 11 10 9 8 7 6 5 

NUMBEROFYEARSOFDATA 

4 3 2 

Figure F4.--Projected total growth in estimates 

of the amount of ultimately 

recoverable natural gas in fields 

discovered before 1979 in the 

conterminous United States versus 

the number of years of data used. 

Thirteen years of data are from · 

1966 to 1978; two years of data are 

from 1977 to 1978 (American 

Petroleum Institute and others, 

1967-1979). 

data are too erratic to permit the calculation 

of growth factors on a State by State basis, the 

table of inferred reserves for the States (table 

F2) was calculated by applying the growth 

factors calculated for the conterminous United 

States as a whole to the State natural-gas 

discovery data. The growth curve (fig. F4) for 

recoverable natural gas was calculated by the 

same method that was used for recoverable oil, 

except that for gas, nine years of data--1970-

1978--were used instead of eight. Figure F4 

shows how varying the length of the data series 

changes the estimate of growth of gas 

reserves. Again, the length of the data series 

was chosen to give an average amount of 

growth. Inferred reserves for natural gas were 

calculated in a manner similar to that for oil. 

For both oil and gas, the growth factors 

were calculated for a particular data series, 

and to apply the factors to another data series, 

for example, to individual field data, would be 

87 

inappropriate. Late reporting of discoveries 

probably is responsible for much of the apparent 

growth in the first two or three years after 

discovery. If this is true, then those fields 

that have been reported grow much less than the 

calculated growth curves might at first lead one 

to believe. 

REFERENCES CITED 

American Petroleum Institute, American Gas 

Association, and Canadian Petroleum 

Association, 1967-1979, Reserves of crude 

oil, natural gas liquids, and natural gas 

in the United States and Canada [annual 

volumes for the years 1966-1978]: New 

York, American Petroleum Institute. 

Arrington, J. R., 1960, Size of crude reserves 

is key to evaluating exploration 

programs: Oil and Gas Journal, v. 58, 

no. 9, Feb. 29, p. 130-134. 

Hubbert, M. K., 1974, U.S. energy resources, a 

review as of 197 2, pt. 1, iYt A national 

fuels and energy policy study: U.S. 93rd. 

Congress, 2d session, Senate Committee on 

Interior and Insular Affairs, Committee 

Print, Serial No. 93-40 (92-75), 267 p. 

Marsh, G. R., 1971, How much oil are we really 

finding: ·Oil and Gas Journal, v. 69, no. 

14, April 5, p. 100-104. 

Mast, R. F., and Dingler, Janet, 1975, Estimates 

of inferred + indicated reserves for the 

United States, in Miller, B. M., Thomsen, 

H. L., Dolton, G. L., Coury, A. B., 

Hendricks, T. A., Lennartz, F. E., Powers, 

R. B., Sable, E. G., and Varnes, K. L., 

Geological estimates of undiscovered 

recoverable oil and gas resources in the 

United States: U.S. Geological Survey 

Circular 725, p. 73-78. 

Pelto, C. R., 1973, Forecasting ultimate oil 

recovery, in Symposium on petroleum 

economics and evaluation: Society of 

Petroleum Engineers, American Institute of 

Mining and Metallurgical Engineers, Dallas 

section, SPE 4261, p. 45-52. 

White, D. A., Garrett, R. w., Jr., Marsh, G. R., 

Baker, R. A., and Gehman, H. M., 1975, 

Assessing regional oil and gas potential, 

in Haun, J. D., ed., Methods of estimating 

the volume of undiscovered oil and gas 

resources: American Association of 

Petroleum Geologists, Studies in geology, 

no. 1, p. 143-159. 

U.S. GOVERNMENT PRINTING OFFICE: 576-034/117-1982