U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2011–3003

January 2011

National Assessment of Oil and Gas Fact Sheet

Printed on recycled paper

Introduction

The U.S. Geological Survey (USGS) in 2010 completed 

an assessment of the undiscovered oil and gas potential of 

the Anadarko Basin Province of western Oklahoma, western 

Kansas, northern Texas, and southeastern Colorado (fig. 1). The 

assessment is based on the geologic elements of each defined 

total petroleum system (TPS), including (1) hydrocarbon source 

rocks (source-rock richness and thermal maturation, hydrocarbon generation, adsorption, and migration); (2) reservoir 

rock type (conventional or continuous), distribution, and 

quality; and (3) types and distribution of reservoir traps and 

seals, including timing relative to petroleum generation and 

migration. Using this geologic framework, the USGS defined 

two TPSs, with 12 included assessment units (AU), and quantitatively estimated undiscovered oil, gas, and natural gas liquids 

resources in each AU (table 1).

The Anadarko Basin Province is in a mature state of exploration and development for conventional resources. Much of 

the production is reported as being commingled from numerous formations that were deposited over broad age ranges; this 

commingling influenced grouping of formations into the AUs. 

The Woodford Composite and Pennsylvanian Composite TPSs 

represent source rock input from numerous Ordovician through 

Pennsylvanian formations. The Woodford Composite TPS 

source rocks primarily contribute to Cambrian through Mississippian reservoirs, and those of the Pennsylvanian Composite 

TPS to Pennsylvanian and Permian reservoirs. Migration and 

accumulation of hydrocarbons from variable sources can occur 

along fault systems and updip from the extent of the Woodford 

Shale and other source rocks. Biogenic gas from the Cretaceous 

Niobrara Formation is produced from western Kansas and 

eastern Colorado; however, that resource was evaluated in the 

Denver Basin Province assessment (USGS Fact Sheet 002–03).

OKLAHOMA

COLORADO KANSAS

TEXAS

NEW

MEXICO

Pennsylvanian 

Composite TPS

Woodford 

Composite TPS

104° W 103° W 102° W 101° W 100° W 99° W 98° W 97° W

39° N

38° N

37° N

36° N

35° N

34° N 0 50 100 Miles

Gulf 

of 

Mexico

TX

NM

CO KS

OK

Anadarko 

Basin 

Province

Anadarko_Fig_1.ai

ANADARKO BASIN

Figure 1. Map showing boundaries of the Anadarko Basin Province (red line), the Woodford Composite total petroleum system (TPS), and the Pennsylvanian Composite TPS.

Assessment of Undiscovered Oil and Gas Resources of the 

Anadarko Basin Province of Oklahoma, Kansas, Texas, and 

Colorado, 2010

The U.S. Geological Survey, using a 

geoscience-based assessment methodology, estimated mean technicallyrecoverable undiscovered continuous 

and conventional resources that total 

495 million barrels of oil, 27.5 trillion 

cubic feet of natural gas, and 410 

million barrels of natural gas liquids 

in the Anadarko Basin Province; this 

assessment includes the Las Animas 

arch area of southeastern Colorado. 

The province is at a mature stage 

of exploration and development 

for conventional resources. Mean 

undiscovered continuous resources 

are estimated at 79 percent of oil, 90 

percent of natural gas, and 81 percent 

of natural gas liquids in the province.
Resource Summary

 The USGS assessment of undiscovered conventional and 

continuous (unconventional) resources within the province 

resulted in mean estimates of 495 million barrels of oil 

(MMBO), 27 trillion cubic feet of natural gas (TCFG), and 

410 million barrels of natural gas liquids (MMBNGL) within 

twelve AUs in the two TPSs (table 1). Much of the remaining 

conventional resources are from field growth in this mature 

province. Continuous resources are focused in the deep part of 

the Anadarko Basin in Oklahoma and Texas. Boundaries of the 

Woodford Shale Oil and Woodford Shale Gas AUs and locations of sweet spots within them were based mainly on (1) extent 

and thickness of the formation, (2) filling of underlying Hunton 

Formation eroded channels, (3) historical and estimated ultimate 

production from existing wells, and (4) levels of thermal 

maturation based on 1D, 2D, and 3D petroleum system models 

and on vitrinite reflectance maps and data. The Thirteen Finger 

Limestone-Atoka Shale Gas continuous AU does not have 

documented production and has limited published information. 

Boundaries for this AU were based largely on characteristics 

such as thickness and lateral extent of included formations from 

Table 1. Anadarko Basin Province assessment results listed by total petroleum system (TPS) and assessment unit (AU). Included are estimated 

volumes of undiscovered technically recoverable oil, gas, and natural gas liquids.

[MMBO, million barrels of oil; BCFG, billion cubic feet of gas; MMBNGL, million barrels of natural gas liquids; gray shading, not applicable. Type refers to 

mainly oil or gas accumulations in the assessment unit. Fractiles (F95, F50, F5) are fully risked estimates. F95 denotes a 95-percent chance of at least the amount 

tabulated. Other fractiles are defined similarly. Fractiles are additive only under the assumption of perfect positive correlation]

well-log examination, and it is within the boundary of wet and 

dry gas generation based on 1D and 3D petroleum system models. This uncertainty is reflected in a fairly broad range of F5 to 

F95 resource estimates (table 1); mean undiscovered resources 

are 6.85 TCFG and 82 MMBNGL.

For Further Information

 Supporting geologic studies of total petroleum systems 

and assessment units and reports on the methodology used in 

the Anadarko Basin Province assessment are in preparation. 

Assessment results and geologic reports will be available as 

completed at the USGS Web site http://energy.cr.usgs.gov/

oilgas/noga/.

Anadarko Basin Province Assessment Team:

 Debra K. Higley (Task Leader; higley@usgs.gov), Stephanie 

B. Gaswirth, Marvin M. Abbott, Ronald R. Charpentier, Troy 

A. Cook, Geoffrey S. Ellis, Nicholas J. Gianoutsos, Joseph R. 

Hatch, Timothy R. Klett, Philip Nelson, Mark J. Pawlewicz, 

Ofori N. Pearson, Richard M. Pollastro, and Christopher J. 

Schenk (National Assessment of Oil and Gas Project Chief).

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

Woodford Composite TPS

Arbuckle-Ellenburger AU Oil 2 5 12 6 7 24 61 28 0 1 2 1

Gas 43 164 371 181 0 1 2 1

Simpson Group AU Oil 2 4 9 5 6 17 39 19 0 0 1 1

Gas 33 114 252 125 2 9 21 10

Viola Group AU Oil 2 5 10 5 3 9 20 10 0 1 2 1

Gas 10 27 58 30 0 0 0 0

Hunton Group AU Oil 2 8 21 9 8 32 87 38 0 1 3 1

Gas 71 281 641 310 0 2 4 2

Mississippian AU Oil 5 16 31 17 15 46 99 50 0 2 4 2

Gas 125 350 663 367 3 8 17 9

Pennsylvanian Composite TPS

Morrowan-Atokan AU Oil 6 14 29 15 21 55 121 61 1 2 5 2

Gas 101 261 469 271 2 5 10 5

Desmoinesian AU Oil 2 6 12 6 8 23 52 26 0 1 2 1

Gas 29 87 167 92 1 3 5 3

Missourian-Permian AU Oil 10 22 38 23 49 114 223 122 2 4 8 4

Gas 61 130 231 136 2 4 7 4

Greater Granite Wash 

Composite AU

Oil 4 14 34 16 22 78 198 90 1 2 7 3

Gas 192 646 1,496 719 7 24 60 27

Total Conventional Resources 35 94 196 102 804 2,458 5,248 2,675 21 70 160 77

Woodford Composite TPS

Woodford Shale Oil AU

Woodford Shale Gas AU

Oil 175 357 730 393 795 1,750 3,851 1,963 22 51 121 59

Gas 8,806 15,131 25,998 15,973 94 178 336 192

Pennsylvanian Composite TPS

Thirteen Finger LimestoneAtoka Shale Gas AU

Oil 

Gas 3,040 6,229 12,763 6,850 33 73 161 82

Total Continuous Resources 175 357 730 393 12,641 23,110 42,612 24,786 149 302 618 333

Total Resources 210 451 926 495 13,445 25,568 47,860 27,461 170 372 778 410