U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2011–3020

March 2011

National Assessment of Oil and Gas Fact Sheet

Printed on recycled paper

Introduction

The U.S. Geological Survey (USGS) recently completed 

an assessment of the undiscovered oil and gas resources in 

Jurassic and Cretaceous strata of the onshore areas and State 

waters of the Gulf Coast (fig. 1). The assessment is based on 

geologic elements of a total petroleum system (TPS), including 

characterization of hydrocarbon source rocks (source-rock 

maturation, hydrocarbon generation and migration), reservoir 

rocks (sequence stratigraphy and petrophysical properties), 

and hydrocarbon traps (trap formation, timing, and seals). 

Using these criteria, the USGS defined an Upper JurassicCretaceous-Tertiary Composite TPS for conventional oil and 

gas resources that extends around the entire Gulf of Mexico, 

including portions of both the United States and Mexico. 

The present assessment of undiscovered conventional oil and 

gas resources includes only that portion of the TPS that lies 

onshore and in State waters of the United States (fig. 1). This 

area extends geographically from the southwest boundary of 

the Western Gulf Province (47) on the Texas-Mexico border 

Assessment of Undiscovered Oil and Gas Resources in 

Jurassic and Cretaceous Strata of the Gulf Coast, 2010

Figure 1.  Map of the Gulf Coast region showing the part of the Upper Jurassic-Cretaceous-Tertiary Composite

Total Petroleum System that is onshore and in State waters of the Gulf Coast of the United States (blue line indicates

onshore boundary in the United States). Province boundaries defined by the U.S. Geological Survey are indicated by

red outlines.

Using a geology-based assessment methodology, the 

U.S. Geological Survey estimated means of 147.4 trillion cubic 

feet of undiscovered natural gas, 2.4 billion barrels of undiscovered oil, and 2.96 billion barrels of undiscovered natural 

gas liquids in Jurassic and Cretaceous strata in onshore lands 

and State waters of the Gulf Coast.

Western Gulf (47)

East 

Texas 

Basin 

(48) Louisiana-Mississippi 

Salt Basins (49)

Florida 

Peninsula

(50) 

Miami

Tampa

Austin

Dallas

Houston

Atlanta

Memphis

Wichita

Nashville Raleigh

Charlotte

Fort Worth Birmingham

Louisville

San Antonio

New Orleans

Saint Louis

Oklahoma City

Corpus Christi

TEXAS

FLORIDA

GEORGIA

OKLAHOMA

KANSAS

ALABAMA

LOUISIANA

SOUTH CAROLINA

COLORADO

MISSISSIPPI

ARKANSAS

MISSOURI

ILLINOIS

TENNESSEE

KENTUCKY

NORTH CAROLINA

VIRGINIA

MEXICO

UNITED

STATES

GULF OF MEXICO

ATLANTIC

OCEAN

 104° 102° 100° 98° 96° 94° 92° 90° 88° 86° 84° 82° 80° 78°

24°

26°

28°

30°

32°

34°

36°

38°

0 200 MILES

100 200 KILOMETERS

50 100
[MMBO, million barrels of oil; BCFG, billion cubic feet of gas; MMBNGL, million barrels of natural gas liquids. Results shown are fully risked estimates. For gas accumulations, all liquids are included as NGL (natural gas liquids). F95 represents a 95 percent chance of at least the amount tabulated; other fractiles are defined similarly. 

Fractiles are additive under the assumption of perfect positive correlation. TPS, total petroleum system; AU, assessment unit. Gray shading indicates not applicable]

Table 1.  Gulf Coast assessment results.

Total Petroleum Systems 

(TPS) 

and Assessment Units (AU)

Field

Type

Total Undiscovered Resources

Oil (MMBO) Gas (BCFG) NGL (MMBNGL)

F95 F50 F5 Mean F95 F50 F5 Mean F95 F50 F5 Mean

Upper Jurassic-Creataceous-Tertiary Composite TPS (50490100)

Norphlet Salt Basins 

and Updip AU (50490102)

Oil 13 48 106 53 8 31 73 34 1 2 6 3

Gas 371 1,579 3,709 1,758 12 53 135 61

Norphlet Mobile Bay 

Deep Gas AU (50490103)

Oil 0 0 0 0 0 0 0 0 0 0 0 0

Gas 208 1,175 4,029 1,514 0 2 7 3

Norphlet South Texas Gas AU 

(50490104)

Oil 0 0 0 0 0 0 0 0 0 0 0 0

Gas 0 153 748 233 0 5 27 8

Smackover Updip and Peripheral Fault Zone AU (50490105)

Oil 27 76 136 78 29 85 169 90 2 7 15 7

Gas 46 151 304 160 4 15 32 16

Smackover Salt Basin AU 

(50490106)

Oil 21 75 149 79 25 90 199 98 2 7 17 8

Gas 265 889 1,693 926 32 112 235 120

Smackover South Texas AU 

(50490107)

Oil 6 22 51 25 7 25 62 28 1 2 5 2

Gas 203 699 1,419 744 19 68 151 74

Haynesville Western ShelfSabine Platform Carbonate 

Gas AU (50490116)

Oil 0 0 0 0 0 0 0 0 0 0 0 0

Gas 143 541 1,180 587 2 8 19 9

Haynesville Shelf Carbonate 

and Sandstone Oil and Gas 

AU (50490117)

Oil 7 27 64 30 9 37 95 43 1 3 9 4

Gas 9 27 75 32 0 1 3 1

Bossier East Texas Basin 

Sandstone Gas AU (50490118)

Oil 0 0 0 0 0 0 0 0 0 0 0 0

Gas 590 2,512 5,806 2,765 8 34 86 39

Bossier Louisiana-Mississippi 

Shelf Edge Sandstone Gas 

AU (50490119)

Oil 0 0 0 0 0 0 0 0 0 0 0 0

Gas 211 945 2,368 1,072 3 13 35 15

Knowles-Calvin Gas AU 

(50490120)

Oil 0 0 0 0 0 0 0 0 0 0 0 0

Gas 621 3,069 7,382 3,423 6 30 78 34

Sligo-James Carbonate Platform 

Gas and Oil AU (50490121)

Oil 11 45 106 50 31 132 336 151 1 6 16 7

Gas 167 587 1,279 640 5 17 41 19

Lower Cretaceous Basinal 

Gas AU (50490122) Gas Not quantitatively assessed 

Sligo Sandstone Gas and Oil 

AU (50490123)

Oil 3 9 19 10 1 4 9 4 0 0 0 0

Gas 140 440 803 453 1 4 9 5

Greater Glen Rose Carbonate 

Shelf and Reef Gas and Oil 

AU (50490124)

Oil 23 71 153 78 78 260 602 290 4 13 32 15

Gas 252 720 1,480 778 7 22 50 25

Albian Clastic AU (50490125)

Oil 11 35 69 37 9 31 67 33 0 1 3 1

Gas 39 116 207 119 1 3 6 3

Updip Albian Clastic AU 

(50490126)

Oil 0 1 3 1 0 0 3 1 0 0 0 0

Gas 0 3 15 4 0 0 0 0

Fredericksburg-Buda Carbonate 

Platform-Reef Gas and Oil 

AU (50490127)

Oil 10 37 83 40 26 100 246 113 1 5 12 5

Gas 120 466 1,041 509 2 8 20 9

Eagle Ford Updip Sandstone Oil 

and Gas AU (50490128)

Oil 41 136 253 141 53 184 381 197 1 4 8 4

Gas 86 289 571 305 3 11 24 12

Conventional Oil and Gas Resources
Table 1.  Gulf Coast assessment results.—Continued

Continuous Oil and Gas Resources

Total Petroleum Systems 

(TPS) 

and Assessment Units (AU)

Field

Type

Total Undiscovered Resources

Oil (MMBO) Gas (BCFG) NGL (MMBNGL)

F95 F50 F5 Mean F95 F50 F5 Mean F95 F50 F5 Mean

Upper Jurassic-Creataceous-Tertiary Composite TPS (50490100), continued

Austin-Tokio-Eutaw Updip Oil 

and Gas AU (50490130)

Oil 6 19 34 20 1 3 6 3 0 0 0 0

Gas 17 47 92 50 0 1 2 1

Austin-Eutaw Middip Oil and 

Gas AU (50490131)

Oil 10 41 95 45 28 118 300 135 2 10 27 12

Gas 109 477 1,192 542 10 46 124 54

Austin Downdip Gas AU 

(50490132)

Oil 3 11 32 13 10 43 130 53 1 4 14 5

Gas 406 1,429 3,013 1,542 46 167 385 185

Post-Ouachita Successor Basin 

AU (50490201) Gas Not quantitatively assessed

Triassic Basins AU (50490202) Gas Not quantitatively assessed

Total Conventional

 Resources 192 653 1,353 700 4,318 17,457 41,084 19,429 178 684 1,633 766

Haynesville Sabine Platform 

Shale Gas AU (50490161) Gas 44,268 59,735 80,604 60,734 22 35 55 36

Haynesville Greater Gulf Basin 

Shale Gas AU (50490162) Gas Not quantitatively assessed

Mid-Bossier Sabine Platform 

Shale Gas AU (50490163) Gas 2,879 4,870 8,240 5,126 5 10 18 10

Bossier Greater Gulf Basin 

Shale Gas AU (50490164) Gas Not quantitatively assessed

Maverick Basin Pearsall Shale 

Gas AU (50490165) Gas 3,386 7,764 17,801 8,817 0 0 0 0

Greater Gulf Basin Lower

Cretaceous Shale Gas AU

(50490166)

Gas Not quantitatively assessed

Eagle Ford Shale Oil AU

(50490170) Oil 341 758 1,687 853 625 1,486 3,533 1,707 12 29 74 34

Eagle Ford Shale Gas AU 

(50490167) Gas 23,470 46,150 90,747 50,219 851 1,809 3,842 2,009

Austin Pearsall-Giddings Area 

Oil AU (50490168) Oil 507 839 1,389 879 674 1,233 2,255 1,319 49 97 193 106

Smackover Downdip 

Continuous Gas AU (50490169) Gas Not quantitatively assessed

Total Continuous

 Resources 848 1,597 3,076 1,732 75,302 121,238 203,180 127,922 939 1,980 4,182 2,195

Total Undiscovered

Oil and Gas Resources 1,040 2,250 4,429 2,432 79,620 138,695 244,264 147,351 1,117 2,664 5,815 2,961

Conventional Oil and Gas Resources

[MMBO, million barrels of oil; BCFG, billion cubic feet of gas; MMBNGL, million barrels of natural gas liquids. Results shown are fully risked estimates. For gas accumulations, all liquids are included as NGL (natural gas liquids). F95 represents a 95 percent chance of at least the amount tabulated; other fractiles are defined similarly. 

Fractiles are additive under the assumption of perfect positive correlation. TPS, total petroleum system; AU, assessment unit. Gray shading indicates not applicable]
eastward into Texas and Louisiana, including the East Texas 

Basin Province (48), and continues to State waters and onshore 

lands primarily in Louisiana, Mississippi, Arkansas, and Alabama in the Louisiana-Mississippi Salt Basins Province (49). 

The TPS also includes Florida and small parts of Oklahoma, 

Missouri, Illinois, Kentucky, Tennessee, and Georgia (fig. 1). 

The Florida Peninsula Province (50) was not assessed as part of 

this study. The Upper Jurassic-Cretaceous-Tertiary Composite 

TPS contains 34 defined assessment units (AUs) for undiscovered conventional and continuous oil and (or) gas resources 

(table 1) within Jurassic and Cretaceous strata (fig. 2) that lie 

predominantly on the coastal plain and in State waters of Texas, 

Louisiana, Mississippi, Alabama, and a small part of the Florida 

panhandle.

Resource Summary

The USGS assessment of undiscovered conventional oil 

and gas resulted in estimated means of 19,429 billion cubic 

feet of gas (BCFG), 700 million barrels of oil (MMBO), and 

766 million barrels of natural gas liquids (MMBNGL) in the 

AUs that were assessed (table 1). For undiscovered continuous 

oil and gas resources, the estimated means are 127,922 billion 

cubic feet of gas (BCFG), 1,732 million barrels of oil (MMBO), 

and 2,195 million barrels of natural gas liquids (MMBNGL) in 

the AUs that were assessed (table 1).

For Additional Information

Supporting geologic studies of Gulf Coast region total 

petroleum systems and assessment units are in progress, as 

well as studies of the methodology used in the assessment of 

both conventional and unconventional resources in Jurassic 

and Cretaceous strata of the Gulf Coast. Assessment results are 

available at the USGS Central Energy Resources Science Center 

Web site: http://energy.cr.usgs.gov/oilgas/noga.

Gulf Coast Assessment Team

Russell F. Dubiel (rdubiel@usgs.gov), Peter D. Warwick 

(pwarwick@usgs.gov), Sharon Swanson (sswanson@usgs.gov), 

Lauri Burke, Laura R.H. Biewick, Ronald R. Charpentier, 

James L. Coleman, Troy A. Cook, Kris Dennen, Colin Doolan, 

Catherine Enomoto, Paul C. Hackley, Alexander W. Karlsen, 

Timothy R. Klett, Scott A. Kinney, Michael D. Lewan, Matt 

Merrill, Krystal Pearson, Ofori N. Pearson, Janet K. Pitman, 

Richard M. Pollastro, Elizabeth L. Rowan, Christopher J. 

Schenk, and Brett Valentine.

Figure 2.  Generalized stratigraphic section showing

geologic units for which petroleum resources were

assessed in the Gulf Coast region. Nomenclature is a

combination of formal and informal groups and formation

and member names that are based on physical or

biostratigraphic correlations in outcrop and subsurface

studies. The nomenclature reflects the common

designation and usage in the region by State, industry,

U.S. Geological Survey, and academic geologists. (TRI.,

Triassic; E., Early; MID., Middle; Ma, million years ago;

Fm., Formation; Gp., Group; Ls., Limestone). EPOCH

AGE

Ma

65.5

CRETACEOUS

LATE EARLY

JURASSIC

 TRI.(part)

Maastrichtian

Campanian

Santonian

Coniacian

Turonian

Cenomanian

Albian

Aptian

Barremian

Hauterivian

Valanginian

Berriasian

Tithonian

Kimmeridgian

Oxfordian

Callovian

Bathonian

Hettangian

Rhaetian

Norian

Carnian

 GROUP OR

FORMATION

 Navarro Gp.

(Escondido Fm.-Olmos Fm.)

 Taylor Gp.

 (San Miguel Fm./

 Anacacho Ls./

Ozan Fm./Annona Chalk)

Austin Gp./Tokio Fm./

 Eutaw Fm.

 Eagle Ford Fm.

Woodbine Fm./Tuscaloosa Gp.

Washita Gp.

 (Buda Ls.)

 Fredricksburg Gp.

(Edwards Ls./Paluxy Fm.)

Glen Rose Fm.

(Rodessa Fm.)

Pearsall Fm.

Sligo Fm.

(Pettet Fm.)

 Hosston Fm.

(Travis Peak Fm.)

Cotton Valley Fm.

Bossier Fm.

Haynesville Fm./

 Gilmer Ls.

Smackover Fm.

 Norphlet Fm.

Louann Salt

 Werner Fm.

Eagle Mills Fm.

70.6

83.5

88.6

99.6

112

125

134

145.5

151

156

161

197

200

LATE MID.E.LATE

PERIOD