U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2016–3085

November 2016 Printed on recycled paper

National and Global Petroleum Assessment

Assessment of Undiscovered Oil and Gas Resources of the 

Mississippian Sunbury Shale and Devonian–Mississippian 

Chattanooga Shale in the Appalachian Basin Province, 2016

Using a geology-based assessment methodology, the U.S. Geological Survey estimated mean undiscovered, technically recoverable 

continuous resources that total 464 million barrels of oil and 4.08 trillion cubic feet of gas in the Lower Mississippian Sunbury Shale 

and Middle Devonian–Lower Mississippian Chattanooga Shale of the Appalachian Basin Province.

Introduction

In 2016, the U.S. Geological Survey (USGS) completed a geology-based assessment of the undiscovered 

oil, gas, and natural gas liquids (NGL) resources of the 

Sunbury Shale and Chattanooga Shale in the Appalachian 

Basin Province. The assessed area comprises parts of 

Alabama, Georgia, Kentucky, Maryland, Mississippi, 

New York, Ohio, Pennsylvania, Tennessee, Virginia, 

andxWest Virginia (fig. 1). The assessment is based on 

the geologic elements of the Devonian Shale–Middle and 

Upper Paleozoic Total Petroleum System (TPS), including (1) hydrocarbon source rocks (source-rock richness 

and levels of thermal maturation, and associated oil and 

gas generation, adsorption, and migration); (2) reservoir 

rock type (continuous or conventional), distribution, and 

properties (composition, porosity, permeability, brittle/

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

and seals, including timing relative to petroleum generation 

and migration. The Sunbury and Chattanooga primarily 

consist of organic-rich marine shales, and the contained 

hydrocarbon resources are considered self-sourced based 

partly on levels of thermal maturation compared to hydrocarbon productive areas. Milici and Swezey (2006) include 

background information on the Sunbury and Chattanooga. 

Assessment unit (AU) boundaries and resource potential 

also were determined using reservoir/source strata thickness, depth, composition, and distribution. Input data 

applied to assess these continuous assessment units are 

listed in table 1. Using this geologic framework, the USGS 

defined one TPS, with five continuous AUs, and quantitatively estimated undiscovered, technically recoverable oil, 

gas, and NGL resources for four of the five AUs (tables 1 

and 2). The unassessed Chattanooga Plateau Shale Oil AU 

is categorized as hypothetical because data were insufficient for quantitative resource assessment.

Undiscovered Resources Summary

The USGS quantitatively assessed undiscovered continuous (unconventional) oil and gas resources in four AUs 

within the Devonian Shale–Middle and Upper Paleozoic 

TPS (table 2). For total undiscovered resources, the 

Figure 1. Map showing the boundaries for five assessment units (AUs) 

in the Lower Mississippian Sunbury Shale and the Middle Devonian to 

Lower Mississippian Chattanooga Shale in the Devonian Shale–Middle 

and Upper Paleozoic Total Petroleum System (boundary not shown) in the 

Appalachian Basin Province.

estimated means are 464 million barrels of oil (MMBO) with an F95–F5 

range from 104 to 1,012 MMBO; 4,084 billion cubic feet of gas (BCFG), 

or 4.08 trillion cubic feet of gas liquids, with an F95–F5 range from 730 

to 9,792 BCFG; and 76 million barrels of natural gas liquids (MMBNGL) 

with an F95–F5 range from 13 to 189 MMBNGL.

Cincinnati Arch

Black

Warrior

Basin

MICHIGAN

INDIANA

KENTUCKY

OHIO

PENNSYLVANIA

ILLINOIS

VIRGINIA

NORTH CAROLINA

SOUTH CAROLINA

GEORGIA

ATLANTIC

OCEAN

Lake

Michigan

ALABAMA

MISSISSIPPI

TENNESSEE

MISSOURI

WEST

VIRGINIA

42°

90° 88° 86° 84° 82° 80°

40°

38°

36°

34°

32°

Lake

Erie

Area of

study

IL IA

WI

MO

FL

MI

AL GA

PA IN

AR

NY

MD

LA

NC

VA TN

KY

MS

OH

SC

WV

ATLANTIC

OCEAN

GULF OF

MEXICO

Sunbury Shale Oil AU

Sunbury Shale Gas AU

Chattanooga Plateau Shale Oil AU

Chattanooga Plateau Shale Gas AU

Devonian Foldbelt Shale Gas AU

Appalachian Basin Province boundary

EXPLANATION

Source: U.S. Department of the Interior National Park Service 0 100 200 MILES

0 100 200 KILOMETERS
ISSN 2327-6916 (print) ISSN 2327-6932 (online) http://dx.doi.org/10.3133/fs20163085

For shale-oil resources, the estimated 

means for the Sunbury Shale Oil AU are 

464 MMBO with an F95–F5 range from 

104 to 1,012 MMBO, 1,237 BCFG with an 

F95–F5 range from 259 to 2,800 BCFG, 

and 37 MMBNGL with an F95–F5 range 

from 7 to 88. For shale-gas resources, 

Table 1. Key assessment input data for four continuous assessment units (AUs) in the Appalachian Basin Province. A fifth continuous AU, 

the Chattanooga Plateau Shale Oil, was not quantitatively assessed because of insufficient data.

[AU, assessment unit; %, percent; EUR, estimated ultimate recovery per well; MMBO, million barrels of oil; BCFG, billion cubic feet of gas. The average EUR input 

is the minimum, median, maximum, and calculated mean. Shading indicates not applicable]

Table 2. Assessment results for four continuous assessment units (AUs) in the Appalachian Basin Province. A fifth continuous AU, 

the Chattanooga Plateau Shale Oil, was not quantitatively assessed because of insufficient data.

[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 under the NGL (natural gas liquids) category. 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. Shading indicates not applicable]

Assessment input data—Continuous AUs

Sunbury Shale Oil AU Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 3,000 4,000,000 9,300,000 4,434,333

Average drainage area of wells (acres) 80 120 240 147

Success ratio (%) 5 30 50 28

Average EUR (MMBO) 0.03 0.05 0.1 0.052

AU probability 1.0

Sunbury Shale Gas AU Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 5,000 6,000,000 12,000,000 6,001,667

Average drainage area of wells (acres) 80 120 200 133

Success ratio (%) 5 30 50 28

Average EUR (BCFG) 0.04 0.08 0.2 0.086

AU probability 1.0

Chattanooga Plateau Shale Gas AU Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 2,000 785,000 4,325,000 1,704,000

Average drainage area of wells (acres) 80 120 180 127

Success ratio (%) 10 50 90 50

Average EUR (BCFG) 0.04 0.08 0.3 0.092

AU probability 1.0

Devonian Foldbelt Shale Gas AU Minimum Mode Maximum Calculated mean

Potential production area of AU (acres) 1,000 220,000 5,300,000 1,840,323

Average drainage area of wells (acres) 60 80 120 87

Success ratio (%) 10 50 90 50

Average EUR (BCFG) 0.04 0.1 0.25 0.107

AU probability 1.0

Total petroleum system 

and assessment units (AUs)

AU

probability

Accumulation

type

Total undiscovered resources

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

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

Devonian Shale–Middle and Upper Paleozoic Total Petroleum System

Sunbury Shale Oil AU 1.0 Oil 104 410 1,012 464 259 1,065 2,800 1,237 7 31 88 37

Sunbury Shale Gas AU 1.0 Gas 250 968 2,386 1,098 3 11 30 13

Chattanooga Plateau Shale Oil AU Oil Not quantitatively assessed

Chattanooga Plateau Shale Gas AU 1.0 Gas 102 479 1,552 610 2 11 39 15

Devonian Foldbelt Shale Gas AU 1.0 Gas 119 873 3,054 1,139 1 9 32 11

Total undiscovered 

continuous resources 104 410 1,012 464 730 3,385 9,792 4,084 13 62 189 76

Reference Cited

Milici, R.C., and Swezey, C.S., 2006, 

Assessment of Appalachian Basin oil 

and gas resources—Devonian Shale–

Middle and Upper Paleozoic Total 

Petroleum System: U.S. Geological 

Survey Open-File Report 2006–1237, 

70 p., accessed October 6, 2016, at 

http://pubs.usgs.gov/of/2006/1237/

of2006-1237.pdf.

the estimated means for the Sunbury 

Shale Gas AU are 1,098 BCFG with an 

F95–F5 range from 250 to 2,386 BCFG 

and 13 MMBNGL with an F95–F5 range 

from 3 to 30. Estimated means for the 

Chattanooga Plateau Shale Gas AU are 

610 BCFG with an F95–F5 range from 

102 to 1,552 BCFG and 15 MMBNGL 

with an F95–F5 range from 2 to 39. For 

the Devonian Foldbelt Shale Gas AU, the 

estimated means are 1,139 BCFG with an 

F95–F5 range from 119 to 3,054 BCFG 

and 11 MMBNGL with an F95–F5 range 

from 1 to 32 MMBNGL.

Appalachian Basin Province Assessment Team

Debra K. Higley, William A. Rouse, Catherine B. Enomoto, Michael H. Trippi, 

Timothy R. Klett, Tracey J. Mercier, Michael E. Brownfield, Marilyn E. Tennyson, 

Ronald M. Drake II, Thomas M. Finn, Nicholas J. Gianoutsos, Ofori N. Pearson, 

Colin Doolan, Phuong A. Le, and Christopher J. Schenk

For More Information

Assessment results are available at the USGS Energy Resources Program 

Web site at http://energy.usgs.gov.