Executive Summary—National Assessment 

of Oil and Gas Project: Geologic Assessment 

Of Undiscovered Gas Hydrate Resources on 

the North Slope, Alaska

Digital Data Series DDS–69–CC

U.S. Department of the Interior

U.S. Geological Survey

By U.S. Geological Survey Alaska Gas Hydrate Assessment Team

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U.S. Department of the Interior

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2013

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Suggested citation:

U.S. Geological Survey Alaska Gas Hydrate Assessment Team, 2013, National Assessment of Oil and Gas Project—

Executive Summary—Geologic assessment of undiscovered gas hydrate resources on the North Slope, Alaska: 

U.S. Geological Survey Digital Data Series 69–CC, 2 p., http://dx.doi.org/10.3133/ds69cc.

ISSN 2327-0271 (print)

ISSN 2327-132x (online)
iii

Contents

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

Resource Summary .......................................................................................................................................1

U.S. Geological Survey Alaska Gas Hydrate Assessment Team ...........................................................1

Figure

1. The Northern Alaska Gas Hydrate Total Petroleum System (TPS), 

and the limit of the gas hydrate stability zone in northern Alaska .......................................2

Table

1. Alaska North Slope–Gas hydrate assessment results...........................................................2
Executive Summary—National Assessment of Oil and 

Gas Project: Geologic Assessment of Undiscovered Gas 

Hydrate Resources on the North Slope, Alaska

By U.S. Geological Survey Alaska Gas Hydrate Assessment Team

The U.S. Geological Survey (USGS) has completed the 

first assessment of the undiscovered technically recoverable 

gas-hydrate resources on the North Slope of Alaska. Using a 

geology-based assessment methodology, the USGS estimates 

that there are about 85 trillion cubic feet (TCF) of undiscovered, technically recoverable gas resources within gas hydrates 

in northern Alaska.

Introduction

U.S. Geological Survey (USGS) assessment of the 

undiscovered, technically recoverable gas-hydrate resources 

beneath the North Slope of Alaska indicates the existence 

of technically recoverable gas-hydrate resources―that is, 

resources that can be discovered, developed, and produced 

using current technology. The assessment is based on the 

geologic elements used to define a Total Petroleum System 

(TPS), including hydrocarbon source rocks (source-rock 

type and maturation and hydrocarbon generation and migration), reservoir rocks (sequence stratigraphy, petrophysical 

properties, seismic attribute development, and prospecting), 

and hydrocarbon traps (trap formation and timing). The area 

assessed in northern Alaska (fig. 1) extends from the National 

Petroleum Reserve in Alaska (NPRA) on the west through 

the Arctic National Wildlife Refuge (ANWR) on the east 

and from the Brooks Range northward to the State-Federal 

offshore boundary (located three miles north of the coastline). This area consists mostly of Federal, State, and Native 

lands covering about 55,900 mi2

. The Northern Alaska Gas 

Hydrate Total Petroleum System (fig. 1) includes Cretaceous 

and Tertiary reservoir rocks that have been divided into 

three assessment units (AUs)―from oldest to youngest, the 

Nanushuk Formation Gas Hydrate AU, the Tuluvak-Schrader 

Bluff-Prince Creek Formations Gas Hydrate AU, and the 

Sagavanirktok Formation Gas Hydrate AU.

Resource Summary

For the Northern Alaska Gas Hydrate TPS, the USGS 

estimates that the total undiscovered natural gas resources 

in gas hydrate deposits range between 25.2 and 157.8 trillion cubic feet (TCF; 95-percent and 5-percent probabilities 

of greater than these amounts, respectively), with a mean 

estimate of 85.4 TCF (table 1). Of this mean estimate, 

(1) 24 percent (20.6 TCF) is in the Sagavanirktok Formation 

Gas Hydrate AU, (2) 33 percent (28.0 TCF) is in the TuluvakSchrader Bluff-Prince Creek Formations Gas Hydrate AU, and 

(3) 43 percent (36.9 TCF) is in the Nanushuk Formation Gas 

Hydrate AU (table 1).

U.S. Geological Survey Alaska Gas 

Hydrate Assessment Team

Timothy S. Collett, Warren F. Agena, Myung W. Lee, John J. 

Miller, Kristen A. Lewis, Thomas D. Lorenson, Margarita V. 

Zyrianova, Kenneth J. Bird, Ronald R. Charpentier, Troy Cook, 

David W. Houseknecht, Timothy R. Klett, Richard M. Pollastro, 

and Christopher J. Schenk.
2 Executive Summary—Geologic Assessment of Undiscovered Gas Hydrate Resources on the North Slope, Alaska

UNITED STATES

CANADA

Umiat

Barrow

Atqasuk

Nuiqsut Kaktovik Deadhorse

Wainwright

Point 

Hope

Prudhoe

Bay

Cape 

Lisburne

Point 

Lay

Icy 

Cape

Point 

Barrow

Smith

Bay

Harrison

Bay Camden

Bay

Alaska State waters

(outer limit)

Brooks Range

CHUKCHI 

SEA

ARCTIC OCEAN

BEAUFORT SEA

National Petroleum 

Reserve—Alaska (boundary)

Arctic National 

Wildlife Refuge (boundary)

Trans-Alaska Pipeline System

Northern Alaska Gas Hydrate TPS

Northern Alaska Gas Hydrate TPS

EXPLANATION

Limit of gas hydrate stability zone

170° 160° 150° 140°

68°

70°

0 50 100 MILES

0 50 100 KILOMETERS

Area of map

ALASKA

Base from U.S. Geological Survey digital data

Albers Conical Equal area projection

Standard parallels 55°N and 65°N

Central meridian 154°W, latitude of origin 50°N

North American Datum of 1983 (NAD 83)

Figure 1. The Northern Alaska Gas Hydrate Total Petroleum System (TPS) (shaded in tan), and the limit of the gas hydrate stability zone 

in northern Alaska (red outline).

Table 1. Alaska North Slope–Gas hydrate assessment results.

[BCFG, billion cubic feet of gas. MMBNGL, million barrels of natural gas liquids. Results shown are fully risked estimates. F95 represents a 95-percent chance of 

at least the amount tabulated; other fractiles are defined similarly. Fractiles are additive, assuming perfect positive correlations. NGL, natural gas liquids; TPS, total 

petroleum system; AU, assessment unit.]

Total Petroleum System and Assessment Unit Field

type

Total undiscovered resources

Gas (BCFG) NGL (MMBNGL)

F95 F50 F5 Mean F95 F50 F5 Mean

Northern Alaska Gas Hydrate TPS

Sagavanirktok Formation Gas Hydrate AU Gas 6,285 19,490 37,791 20,567 0 0 0 0

Tuluvak-Schrader Bluff-Prince Creek Formations 

Gas Hydrate AU

Gas 8,173 26,532 51,814 28,003 0 0 0 0

Nanushuk Formation Gas Hydrate AU Gas 10,775 35,008 68,226 36,857 0 0 0 0

Total Undiscovered Resources 25,233 81,030 157,831 85,427 0 0 0 0

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