The National Petroleum 

Reserve in Alaska 

Earth-Science Considerations 

By George Gryc 

U.S. Geological Survey Professional Paper 1240-C 

A story of the building of a geologic data base, 

the interaction of industry and Government, 

and the rote of the US Geological Survey 

U.S. Government Printing Office, Washington, D.C., 1985 
/ 

Acknowledgments 

United States Department of the Interior 

DONALD PAUL HODEL, Secretary 

Geological Survey 

Dallas L. Peck, Director 

This book is the product of many contributors who have provided text, graphic 

material, and ideas. They are, in alphabetic order, Kenneth J. Bird, Mary M. 

Brosge, Catherine C. Campbell, Sarah B. Griscom, George Gryc, Paul Y. W. Ho, 

Charles E. Kirschner, Robert J. Lantz, Leslie B. Magoon III, Linda OlsonGonzales, and Norman Scott III. To these and the many other members of the U.S. 

Geological Survey who supported, reviewed, and provided technical assistance, I 

express my appreciation. 

Library of Congress Catalog-Card 1\'o. 85-600533 

COVER: Landsat photograph of the National Petroleum Reserve in Alaska 

area. GEOPIC image mosaic © Earth Satellite Corp., Chevy Chase, Md.; 

used with permission. 
The National Petroleum 

Reserve in Alaska 

Earth-Science Considerations 

By George Gryc 

U.S. Geological Survey Professional Paper 1240-C 

A story of the building of a geologic data base, 

the interaction of industry and Government, 

and the rote of the US Geological Survey 

U.S. Government Printing Office, Washington, D.C., 1985 

The Colville River, frozen solid 8 to 9 months out of the year, 

~ meanders across the Arctic Coastal Plain from the Brooks Range. 

Photograph by j eep johnson. 

Foreword 

The long history of petroleum exploration in Arctic Alaska by 

Government and industry began in earnest in 1923 with the 

establishment of Naval Petroleum Reserve No. 4 and climaxed in 

1968 with the discovery of the largest oil field in North America 

at Prudhoe Bay. Geologists and topographers of the U.S. Geological Survey played a vital role in this exploration. 

The administrative programs of and ~ctions by the Federal 

Government in the development of this region have been driven 

by the Nation's needs for energy fuels, predictions of coming 

shortages, and actual short-term crises, such as the Arab oil 

embargo of 1974. The Nation's concerns for the environment 

and the well-being ofthe Native population in this remote Arctic 

wilderness have added to the complexities of such policy decisions. 

This book provides a graphic overview of the gradual 

accumulation of information on the geology and geography of 

northern Alaska, exemplifying the leadtime required for 

resource exploitation and the difficult environmental considerations involved. It should serve to illustrate how interagency 

cooperation and a good working relationship between Government and industry have functioned during a crucial period of 

resource expansion and ecologic awareness, in successfully 

dealing with the challenges that still face us for an uncertain 

energy future. 

Dallas L. Peck 

Director 

Alfred H. Brooks writing in hisfield notebook. In 1903, the Division 

of Alaskan Mineral Resources was established within the USGS. 

Brooks was its first Geologist in Charge and continued in this caparity 

until his death in 1924. He was instrumental in planning some of the 

first geologic explorations, and the topographic-mapping progmm of 

the newly established Naval Petroleum Reserve No. 4 and the Brooks 

Range were named in his honor. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA Ill 
Scientists visiting Barrow seek refuge from the foul weather beneath a 

handmade umiak. Photograph courtesy of George Gryc. 

IV THE NATIONAL PETROLEUM RESERVE IN ALASKA 
The National Petroleum Reserve 

in Alaska 

Introduction C 1 

What and where is the NPRA-and how was it 

established? C4 

NPRA established C4 

Geographic setting C6 

Who and what live on the North Slope? C8 

When, by whom, and how was the NPRA 

explored? C 10 

Early exploration ClO 

Geologic and topographic surveys, 1923-26 ClO 

The Pet-4 exploration program, 1943-53 C 14 

The 1974-82 exploration ofNPR-4/NPRA C15 

Summary of significant events in the history 

of petroleum exploration in Alaska C 17 

What are the geological, geophysical, and 

geochemical factors considered in 

petroleum exploration and resource 

assessment? C19 

Geologic history C20 

Structural elements and stratigraphic 

sequences C22 

Subsurface geology C24 

Geophysical surveys C24 

Exploratory wells C28 

Subsurface stratigraphy C32 

Source rocks C34 

Reservoir rocks C 36 

What were some of the geotechnical, 

engineering, and environmental 

considerations in the exploration and 

development of the NPRA? C44 

Surficial materials C44 

Permafrost C48 

Environmental stipulations and monitoring 

'frafficability and movement of supplies and 

materials C56 

Logistics C57 

Airstrips C59 

Ice roads C62 

Drillsite construction C65 

One-season drill pads C65 

Year-round drill pads C71 

How were cleanup and rehabilitation 

accomplished? C72 

What is the story of the Barrow gas fields? 

The role of the USGS at Barrow C79 

Gas consumption C80 

Gas production C 81 

C52 

C76 

Prospects for supplying future demands 

The USGS' accomplishments at Barrow 

C85 

C87 

What is happening with the leasing of NPRA 

lands? C89 

What is the leasing program? C89 

Summary of the USGS' accomplishments in 

How were oil and gas resources estimated? C40 the NPR-4/NPRA program C90 

Exploration program and hydrocarbon 

assessment C90 

Cleanup, rehabilitation, and environmental 

considerations C 91 

Operation and maintenance of the Barrow 

gas fields C92 

Termination of the NPRA program C92 

References cited C93 

THE NATIONAL PETROLEUM RESE~YE" IN ALASKA v 
166° 162° 160° 158° 154° 152" 

0 
148° 146° 144° 142° 140° 

""\ 

) E A N 

I 

B A u 0 R T s E 

134" 

Introduction 

On February 27, 1923, President Warren G. Harding issued an Executive Order establishing the 

Nation 's fourth Naval Petroleum Reserve 

(NPR-4 )-an area of about 3 7,000 square miles-

, in the west half of what was to become one of the 

most productive petroleum basins in the United 

States. Exploratory expeditions and commercial 

enterprises, whaling, shipping, and trading in the 

1800's had provided some sketchy information 

about the geography and resources of Arctic Alaska. 

However, the first systematic studies of the geology 

and geography of the region began with the traverse in 1901 by E C. Schrader and W J. Peters of the 

U.S. Geological Survey (USGS); their report was 

published in 1904. A brief note on the oil seepages 

at Cape Simpson was published by the USGS in 

1 

) 1909, and in 1919 E. de K Leffingwell published a , • . •• 

M more complete description in USGS Professional . ll' ~'il \ " 

Paper 109; his descriptions were based in part on ~ "' C> ~ work done by "Sandy" Smith in 1917. In 1921, ~~ ~·. ' 

several applications for prospecting permits were ·. · 

filed under the old mining laws. Thus began the ·~. · . delineation and exploration of the northern Alaska 0 • #S' • I petroleum province-exploration that was to have 11<e ~ 

a profound effect on the indigenous population, on , . : · / 

the State of Alaska, and, indeed, on the whole ~·· · (,.::~ 

Nation. .mP'pell '.' ~' Jo- J'='D ~ 

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C2 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

Recognizing the need for more complete information on the new Reserve, the U.S. Navy requested 

the USGS to map the area covered by NPR-4 and 

the assess the petroleum resources. The fieldwork 

was done from 1923 to 1926, and the results were 

published in 1930. From 1944 through 1953, the 

U.S. Navy undertook the first modern oil-exploration program in the Arctic. The USGS again worked 

with the Navy and, beginning in 1958, compiled 

and published all the available technical data in 

Professional Papers 301 through 305. Several noncommercial hydrocarbon accumulations were discovered by the Navy, and the feasibility of using 

modern petroleum exploration and production 

methods in the Arctic was established and documen ted. 

In 1976, NPR-4 was renamed the National 

Petroleum Reserve in Alaska (NPRA), and the USGS 

was assigned the lead responsibility for further 

exploration. Additional gas accumulations were discovered in the NPRA but were of insufficient size to 

be developed for export. However, the knowledge 

of the geology of Arctic Alaska and its potential 

resources was expanded significantly. 

The early USGS expeditionary surveys 

(1901-26), as well as the more recent exploration 

activities (1944-82), in the NPRA have been in 

keeping with the Survey's charter to survey and map 

the topography, hydrology, and geology of the 

Nation and to assess its water and mineral 

resources. To fulfill these responsibilities, the USGS 

is continually increasing its capabilities not only by 

collecting additional data but also by research in 

the basic principles of the earth sciences. Ongoing 

studies include the source of hydrocarbons (oil, 

gas, and coal); hydrocarbon maturation, migration, 

and accumulation over geologic time; and the 

structural and stratigraphic geologic factors that 

lead to accumulations of these vital commodities. 

"Sandy" Smith holds a mammoth tusk found in gravel beds of the 

Colville River, 1924. Photograph courtesy of PhillipS. Smith. 
The basic knowledge gained from these studies 

has been, and continues to be, made available to the 

public through written reports and maps. Building 

on this information base, oil companies have 

explored and discovered the largest hydrocarbon 

accumulation in North America at Prudhoe Bay on 

the Arctic coast, just east of the NPRA. In addition, 

new interpretations of the geology of the Arctic and 

its relation to that of the rest of the world have 

added to our understanding of Earth processes. The 

resource discovery and development at Prudhoe 

Bay have quickened exploration throughout the 

Arctic and focused worldwide attention on this 

frontier region. 

The fascinating story of the NPRA and the role of 

the USGS from 1901 to 1984 is outlined in the pages 

that follow. This story serves as a case history of ( 1) 

the building of a geologic data base that preceded 

discovery, ( 2) a good working relationship 

between Government and industry, and ( 3) interagency cooperation. 

Some of the first exploratory wells inN P R -4 were drilled at the Umiat 

oil field, about 194 5. Photograph by George Gryc. 

Robert Detterman and George Gryc discuss Alaskan petroleum 

resources. Tilted oil-rich shale beds are visible in the background. 

Photograph courtesy of George Gryc. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C3 
What and where is the 

NPRA-and how was it 

established? 

Oil seeps, such as this one near Simpson, provided clear evidence to 

early explorers that petroleum-rich rocks were present beneath the 

Arctic tundra. Photograph by George Gryc. 

NPRA established 

In 1923, President Warren G. Harding set aside, 

by Executive Order, a Naval Petroleum Reserve, 

later designated No. 4, in Arctic Alaska. His 

Executive Order reads, in part: 

"Whereas there are large seepages of petroleum 

along the Arctic Coast of Alaska and conditions 

favorable to the occurrence of valuable petroleum 

fields on the Arctic Coast and, 

WHEREAS the present laws designed to promote 

development seem imperfectly applicable in the 

region because of its distance, difficulties, and large 

expense of development and, 

WHEREAS the future supply of oil for the Navy is 

at all times a matter of national concern, 

Now, THEREFORE, I, WARREN G. HARDING, 

President of the United States of America, by virtue 

of the power in me vested by the laws of the United 

States, do hereby set apart as a Naval Petroleum 

Reserve all of the public lands within the following 

described area not now covered by valid entry, 

lease or application: * * *" 

C4 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

WARREN G. HARDING 

The White House, 

Feb. 27, 1923. 

No. 3797-A. 

The first description of oil seepages at Cape Simpson by A. H. Brooks was published in 1909 in USGS 

Bulletin 3 79. Eskimos had known of these seepages, 

as well as of oil shales that burned like wood; they 

had used both for fuel long before recorded history. 

Although these leads were in a remote and isolated 

region of the then Territory of Alaska, oil prospectors were already following up on them. Crude oil 

had been discovered and produced in the conterminous United States, but experts, including 

some prominent geologists, were predicting that 

resources were limited and soon could be in short 

supply. Oil was rapidly replacing other sources of 

energy (coal and whale oil} and oil for ships was 

considered critical to the Nation's welfare and 

defense. Thus, the establishment of a Naval 

Petroleum Reserve in Arctic Alaska was fitting. 
Eskimo canoe outfitted with a whale-darting gun, ready for the hunt, 

about 1924. Photograph by Charles Brower. 

Drill rig at Prudhoe Bay. Man)' wells produce mon• tha11 5,111111 

barrels of oil per day. PhotografJh by Robat La11tz. 

Eskimos (about 1924) used whale oil as wl'll as oil shal!'furfiu•llollg 

before recorded histmy . PhotografJh by Chades Browa. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA CS 
Geograp~cse«ing 

The entire NPRA is north of the Arctic Circle. It 

occupies an area about the size of the State of 

Indiana-some 37,000 square miles. Its north 

boundary is the Arctic Ocean, and about half of its 

south boundary follows the watershed divide of the 

western Brooks Range, thence northward to the 

Colville River, and along that river to the Arctic 

coast. 

Northern Alaska and the NPRA are divided into 

three major physiographic provinces: the Arctic 

Coastal Plain, the foothills, and the east-west-trending Brooks Range that cuts off this Arctic region 

from the rest of Alaska. The Brooks Range forms a 

major watershed, the north slope of which drains 

into the Arctic Ocean-thus the terms '1\.rctic 

Slope" and "North Slope" of Alaska. The mountains 

form an arc, concave northward, of complexly 

folded and faulted rocks. Peaks range in elevation 

from 3,000-4,000 feet in the west to more than 

9,000 feet in the east. The foothills immediately to 

the north consist of low synclinal mountains separated by broad anticlinal lowlands that give way to 

long, continuous, east-west-trending ridges covered by a green tundra mat. These ridges gradually 

blend into the vast, nearly treeless coastal plain 

dotted with literally thousands of shallow northwest-oriented lakes. 

C6 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

Typical scenes in the three physiographic provinces of northern ~ 

Alaska. 

From north to south, the NPRA conszsts of (1) the Arctic Coastal 

Plain, a broad,flat expanse dotted with lakes; (2) the foothills, an area 

of rolling hills; and (3) the Brooks Range, a rugged mountain range 

with elevations as high as 5,020 feet within the NPRA and peaks of 

8,000 to 9,000 feet near the United States-Canadian border. 
168 166' 

Folded rocks of the foothills region. Photograph by Irvin Tailleur. 

156 150 148' 1 .... 

0 c E A 

B A Uif" 

The lkpikpuk River winds across the Arctic Coastal Plain. Photograph by George Gryc. 

0 

N 

I s E 

R T ~ 

jagged, snow-capped mountains provide a backdrop for Chandler 

Lake, a glacial lake in the Brooks Range. Photograph by George 

Gryc. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C7 
Who and what live on 

the North Slope? 

Eskimos gather to celebrate a good whale catch near Barrow, about 

1924. Photograph by Charles Brower. 

Fewer than 4,000 Eskimos live within the NPRA. 

They are now concentrated in two coastal villages-Barrow and Wainwright-and two inland 

villages-Atqasuk and Nuiqsut-on the banks of 

the Meade and Colville Rivers. The NPRA lies 

entirely within the boundaries of the North Slope 

Borough. In Alaska, a borough is the political subdivision below State and replaces the county or 

parish subdivisions of other States. As such, the 

North Slope Borough is the largest "county" in the 

United States and actually is larger than most States. 

Other Eskimo communities in the borough are 

Anaktuvuk Pass, Kaktovik, Point Hope, and Point 

Lay. Some 2,000 oil-field employees and service 

personnel live and work in the Prudhoe Bay area. 

The total population of the borough is about 6 ,000. 

The borough headquarters are in Barrow, the 

largest community on the North Slope. 

Archeologic evidence from northern Alaska documents the presence of early inhabitants, possibly 

the Eskimo's ancestors, for at least the past 8,000 

years. They were nomadic hunting people, following sea mammals along the coast and caribou and 

other wildlife inland. 

C8 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

The most abundant member of the present animal population is the brown lemming of migratory 

fame. The NPRA is also the home of the Arctic 

caribou, musk ox, moose, wol( wolverine, fox, and 

barren-ground grizzly. Dall mountain sheep live in 

the bordering Brooks Range and nearby hills. 

Numerous birds visit the area during the short 

summer months, and thousands of waterfowl, 

ducks, geese, swans, and loons nest in the many 

lakes and ponds. No list of wildlife would be complete without the ubiquitous mosquito, swarming 

in unbelievable numbers from early June to August! 

Although the North Slope is commonly 

described as a flat treeless plain, small trees (willow, 

birch, alder, and poplar) grow in some of the river 

valleys, generally only a few feet high but, in favorable places, as high as 15 feet. Flowering plants are 

abundant, blooming and fading quickly in the continuous summer sunlight. The tundra, a thick 

spongy matlike growth, is made up predominantly 

of grasses, sedges, mosses, lichens, and prostrate 

shrubs or bushes. Walking on this spongy tundra 

mat can be very tiring for humans. 
Flowers cling to the rocky slopes of the Brooks Range. Photograph by 

jeep johnson. 

Caribou grazing in Arctic cottongrass, Eriophorum vaginatum. 

Each year, caribou migrate from south of the Brooks Range across the 

tundra to their calving grounds in the foothills and Arctic plaim. 

Photograph by john Haugh. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C9 
When, by whom, and 

how was the NPRA 

explored? 

Early exploration 

Between 1800 and 1900, several hardy explorers 

sailed along the Arctic coast and described and 

named the major geographic features. Much of the 

sealane traffic, however, was by enterprising traders 

and whalers. It is interesting to note that the oil 

business, in one form or another, has had the greatest impact on the North Slope and its inhabitants. 

The first big push to the Arctic was in search of 

whale oil, which, in the years before the Civil War, 

was the principal fuel for lamps and a common 

lubricant. The premium grade of fuel came from 

sperm whales, and the regular grade from bowhead 

and other species of whales. The rising industrialization of the United States and the heightened 

emphasis on education (requiring better light for 

evening study) created a rapid increase in demand. 

In 1823, sperm oil sold for 45 cents a gallon, but by 

1866 the price rose to $2.55 a gallon-the first "oil 

shortage." The relieffor this shortage came through 

the discovery and development of a more abundant 

and cheaper source of fuel, petroleum. Ironically, 

the next several waves of exploration and development in Arctic Alaska focused on a search for "rock 

oil." 

In winter 1885-86, Lt. George M. Stoney participated in expeditions sponsored by the U.S. Naval 

Institute that explored the Brooks Range from the 

south. Ens. W L. Howard of the U.S. Navy crossed 

the Brooks Range in 1886, and continued overland 

across the Colville River valley and thence down 

the Chipp River by skin boat to Point Barrow. He 

described what were undoubtedly lumps and pebbles of oil shale along the Etivluk River. His report, 

published in 1900, may have been the first recorded 

suggestion of the oil potential of northern Alaska. 

However, this material and seepage tars had been 

known and used by the Eskimos before recorded 

history. 

Frank C. Schrader, 1910. The first systematic survey of the North 

Slope was made in 1901 with Schrader as geologist and W .J. Peters, 

an experienced topographer and explorer, in charge. The geography 

and geology of an entirely new section of northern Alaska were studied 

by Peters and Schrader, much of it in the NPRA area. 

C10 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

Geologic and topographic 

surveys, 1923-26 

The first systematic topographic and geologic 

survey across the Brooks Range and the North 

Slope was by F. C. Schrader and W ]. Peters of the 

USGS in 1901; the results were published in 1904 in 

Professional Paper 20. Schrader described thick 

marine sequences and noted broad anticlinal structures-both of prime importance in the search for 

oil. Thus, by 1923, when the lands were set apart, 

three of the prerequisites for the occurrence of 

petroleum were already known to be present: 

source rocks, such as organic marine deposits, 

including oil shale; potential reservoir rocks, 

including limestone and sandstone; and favorable 

structures, such as anticlines. In addition, oil 
seepages were found along the Arctic coast. The 

region had already attracted the attention of the 

new oil industry, and several applications for prospecting permits were filed under the old mining 

laws on claims near Cape Simpson, Peard Bay, and 

along the Meade, Kukpowruk, and Kokolik Rivers. 

About ISO miles east of NPR-4, E. de K Leffingwell completed his classic work in the Canning 

River region. From 1906 to 1914, Leffingwell mapped the Arctic coast from Barrow to the United 

States-Canadian border. He named and described 

the now-famous Sadlerochit Group, which includes 

the primary oil reservoir of the Prudhoe Bay field. 

His report, published in 1919 as USGS Professional 

Paper 109, is now a collector's item. The region 

mapped by Leffingwell from the Canning River to 

the border was set aside in 1960 as the Arctic 

National Wildlife Refuge (ANWR). 

ErnPst de K. LP!Jinpoell. Betwem I 906 and I 9 I 4 LP[fingwell mappnl in the Canning River region from Ba 1-row to the United StatesCanadian border. His expedition was privately fiuuled, half by his 

father. Toward the close of his fieldwork, tlu USGS provided him with 

offte(' space to write and compile his maps, and eventually Jmb/ish.ed 

his work in I 919. PlwtograjJh by George Gryc. 

Sketch map showing the progress of mapping, seismic sun1eying, and 

drillingfrom 1944 to 1953 (modified from Reed, 1958). 

• ••• U.S. Geological Survey 

•••• Shrader 

•••• Foran 

••• I Stoney 

Bt1LIZI'IN IU PLATS I 

THE NATIONAL PETROLEUM RESERVE IN ALASKA Cll 
The International Boundary Commission completed locating and marking the border between 

the United States and Canada in 1912, and additional geologic information was collected along it 

by USGS geologists attached to the mapping party. 

Thus, the geology and geography of the east edge 

of this potential petroleum province were known 

and mapped in a general way before the establishment of the Reserve. However, there remained a 

virtually unknown gap, 130 miles wide, between 

the Canning and Colville Rivers. That area included 

the Prudhoe Bay oil and gas fields. 

NPR-4 was defined, and its boundaries 

described, on the basis of explorations carried out 

before 1923. In delineating the Reserve, account 

was taken of the observations of oil seepages at 

Cape Simpson, the early explorations by the U.S. 

Navy (particularly Howard's traverses in the western area), and the traverse by Schrader and Peters 

along the Colville River-the east boundary of the 

Reserve. Although some detailed surveys had been 

made by Leffingwell and the United States-Canadian-boundary survey teams, their information was 

not considered to warrant a change in delineation 

of the boundary. Furthermore, the northwest coast 

of Arctic Alaska was more accessible by sea than the 

northeast coast. 

Smith and Mertie party resting with dog teams along the Colville 

River, 1924. The first expedition started from Tanana on February 

17, but it was not until April 2 that all supplies, including four 

specially built canoes, were saf e in the first camp on the Arctic 

drainage, and it was May 30 before the streams were open enough to 

allow travel by canoe. Photograph by W. R. Smith. 

USGS surveying camp on the banks of the Canning River where 

Leffingwell worked. Photograph by George Gryc. 

Cl2 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
In 1923, little was known of the interior of the 

new Reserve. The U.S. Navy recognized that more 

geologic and geographic information would be 

required for proper management, and so the USGS 

was asked to survey the region. From 1923 through 

1926, USGS parties traversed the Reserve along the 

major rivers and crossed the Brooks Range through 

Howard Pass and at the head of the Colville River. In 

1930, the results of these field studies and surveys 

by P. S. Smith, ). B. Mertie, Jr., and others were 

published in USGS Bulletin 815. This classic report 

includes the first topographic and geologic maps of 

the Reserve, as well as descriptions of the rock 

sequences and structures, and an analysis of the 

mineral potential of the region , including 

petroleum and coal. Although the authors could 

not ide ntify the precise age or distribution of the oil 

shales, they concluded that these rocks were the 

most likely source of crude oil. They felt that 

sources in Paleozoic rocks were "extremely problematic" and that, because the Cretaceous rocks 

were of shallow marine and terrestrial origin, oil 

deposits de rived from them were "like ly to be small 

and of extremely sparse distribution." Smith and 

Me rtie noted the numerous anticlinal structures in 

the Cretaceous sequences, as we ll as the faulted and 

overthrust structures in the Paleozoic rocks of the 

Brooks Range, and concluded that the regional dip 

of the older rocks was monoclinal to the north. 

Thus, pre-Cretaceous rocks at Cape Simpson and 

along the Arctic coast would be be low practical 

drilling depth. They recommended that the next 

steps in evaluating the petroleum possibilities 

should be drilling for stratigraphic and structural 

information in the vic inity of Cape Simpson, followed by geologic field studies, and then drilling in 

other areas that these studies might indicate to be 

favorabl e . 

PhilipS. Smith, about 1915. Smith was Chief Alaskan geologist from 

1925 until he retired in 1946. At the request of the Department ofthe 

Navy , the USGS was incfuded in thrfirst explorations of the newly 

established NPR-4. 

W. T. Foranfil'ld party in Noatak, about / 924. From left to right, F. 

W. Edgard, W. T. Foran, 0. L W1~>:, and H. G. Hughes. In 1943 , 

U . Fom n railed allention to the fJ elmlewn fJotential of N PR-4 as 

World Wa r II brought an incrmsingdn nandfor pt•troleu m. Sparked 

bv hi1 tnrou ragemenl, the first modern systematic oil-txfJiomtion 

progmm began in NPR-4 (1944 until/953). 

.John Beaver M ertie, 1915 . Mertie began his long geologic career 

with the USGS in 1908 and finished his last publication, a professional paper, in 1979. Along with Philip S. Smith , Mertie led the 

expedition into N PR-4. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA Cl3 
The Pet-4 exploration 

progrann, 1943-53 

From 1926 to 1943, little interest was shown in 

the petroleum potential of NPR-4. There was then 

no shortage of petroleum either for the U.S. Navy or 

for industry, and the remote and frigid Arctic was 

not an attractive target for commercial exploration. 

However, World War II brought a new perspective 

and an increasing demand for petroleum products 

to fight a highly mechanized war. In 1943, Lt. W T 

Foran, a former USGS geologist and a Naval Reserve 

officer, prepared a memorandum to the U.S. Bureau 

of the Budget, calling attention to the petroleum 

potential ofNPR-4. Consequently, in 1943 the Secretary of the Interior issued Public Land Order 82, 

which withdrew from further entry all the possible 

petroleum areas of Alaska, including lands north of 

the drainage divide of the Brooks Range. Later in 

1943, the U.S. Bureau of Mines fielded a party to 

investigate and sample the known oil seepages and 

to check on reported seepages elsewhere in northern Alaska, including those on the Colville River at 

the base of Umiat Mountain. In early spring 1944, Lt. 

Foran made a quick reconnaissance of the Reserve, 

including the Umiat anticline, and reported that in 

his opinion a petroleum potential of major importance existed in NPR-4. On the basis of Foran's 

enthusiastic report and the perceived need for 

additional domestic oil supplies, a major exploration program, commonly called Pet-4, was started. 

This program had a tremendous impact on not only 

the future of petroleum exploration but also many 

aspects of life in the North American Arctic. 

The Pet-4 program established the feasibility 

and practicality of carrying out large-scale modern 

oil-exploration operations in the Arctic, and 

developed many new techniques for such operations. During the period 1945 through 1952, 45 

shallow core tests and 36 test wells were drilled in 

and adjacent to NPR-4. Public Land Order 82 and 

the addition of enabling appropriation language 

permitted exploration in adjacent areas. This drilling resulted in the discovery of oil deposits at 

k :'::':f 1944- 46 c::::::::J1947- 48 1949 50 1951 53 

Progress of geologic investigations in northwestern Alaska (modified 

from Smith and Mertie, 1930). 

Umiat, Cape Simpson, and Fish Creek, gas deposits 

at Umiat, Barrow, and Gubik, and prospective gas 

deposits at Meade, Square Lake, and Wolf Creek. 

Operating bases were established (and still exist) at 

Barrow and Umiat; the gas deposit at Barrow was 

developed, and gas was produced for use originally 

by the U.S. Navy base and other Government 

installations and, in 1964, by the entire Barrow 

community. The Pet-4 Barrow camp facility 

evolved into the Naval Arctic Research Laboratory, 

which was the hub of U.S. Arctic scientific investigations until it was decommissioned in 1981. 

The USGS contribution to this program included 

surface geologic mapping of the Reserve and 

adjoining areas, study of subsurface samples and 

geophysical data, an airborne magnetic survey, 

interpretation of the geologic framework, assessment of potential resources, and production of the 

first complete set of planimetric maps of all of 

northern Alaska. 

A series of reports on the Pet -4 program were 

prepared and published by the USGS as Professional 

Papers 301 through 305. They include a historical 

account, description of logistics and operations, 

well histories and descriptions, a geophysical 

report, and geologic maps and descriptions of the 

extensive surface mapping. Thus, a general geologic framework for all of northern Alaska became 

available for the first time. 

C14 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
The 1974-82 exploration of 

NPR-4/NPRA 

The discovery of oil and gas at Prudhoe Bay in 

1968, in combination with the Arab oil embargo of 

1974, stimulated the U.S. Navy to propose, and the 

Congress to approve, the next exploration program 

in the Reserve. Between 1974 and 1977, the Navy 

drilled seven test wells in the northeast corner of 

the Reserve, following the Prudhoe trend and hoping for similar results. The Navy also drilled four 

wells in the Barrow area and discovered the East 

Barrow gas field, thus providing an additional supply of gas for local use. 

In 1975, the U.S. Navy signed a 5-year contract 

with Husky Oil NPR Operations, Inc., to manage 

and supervise all aspects of the exploration program. 

In 1976, the Naval Petroleum Reserves Production Act (Public Law 94-258) authorized further 

development and actual production for sale of 

crude oil from NPR Nos. 1, 2, and 3 in California and 

Wyoming, and redesignated NPR-4 as the NPRA. 

Thus, the purpose of these Reserves was redirected 

to augment domestic supplies of crude oil. The act 

also required studies of other resources and alternative management systems for NPRA. Responsibility for these studies and for continuation of the 

NPRA exploration program was transferred to the 

Secretary of the Interior, who, in turn, assigned to 

the USGS three duties: ( 1) furthering of the exploration program; ( 2) continuation of the operation, 

maintenance, and production of the gas fields at 

Barrow; and ( 3) cleanup of debris left from previous activities in and adjacent to the NPRA. 

The USGS took over management of the program, 

including all contracts and facilities, on June 1, 

1977. The primary objective of the exploration 

program was defined as an assessment of the oil and 

gas potential of the entire Reserve. A secondary 

objective was the discovery of commercially producible deposits. Thus, all tests were drilled "on 

structure," to the extent that this could be determined. A total of 28 test wells were drilled in the 

period 1974 to 1982, of which 7 were under U.S. 

Navy management. One, the W T Foran test well, 

and a followup, the J. W Dalton test well, penetrated 

a section of favorable rock similar to that at Prudhoe 

Bay, but only shows (indications) of oil were found. 

Apparently, oil had accumulated in quantity at these 

localities but had subsequently migrated 

elsewhere. 

1 \ c ~ c 

0 C £A 

IV EXPLORATION WELLS 1975-1981 

p.. 

50 MILES 

I I I I 

I I I I 

50 KILOMETERS 

Exploration wells in the NPRA drilled from 1975 to 1981 (from 

Mitchell, 1983). 

N 

1 

1. Cape Halkett 

2. S. Harrison 

3. E. T eshekpuk 

4. Atigaru 

5. W. Fis~ Creek 

6. W. T. Foran 

7. S. Simpson 

8. Drew Point 

9. S. Meade 

10. Kugrua 

1 1. N. Kalikpik 

12. lnigok 

13. Tunalik 

1 4. lkpikpuk 

15. Peard 

16. E. Simpson No.1 

17. J. W. Dalton 

18. Lisburne 

19. Seabee 

20. Walakpa No. 1 

21. E. Simpson No. 2 

22. W. Dease 

23. Awuna 

24. Walakpa No. 2 

25. N. lnigok 

26. Kuyanak 

2 7. T ulageak 

28. Koluktak 

THE NATIONAL PETROLEUM RESERVE IN ALASKA ClS 
Several test wells were drilled on the flank of the 

Barrow structure, and a new gas field was discovered at Walakpa, 14 miles southwest of Barrow_ 

This deposit may be useful to the Barrow community but probably is of insufficient size to warrant development for export to the "South 48." 

Farther south on the downslope of the PrudhoeBarrow trend, test wells were drilled to explore the 

wedge edge of potential reservoir rocks, and two 

deep test wells were drilled near the center of the 

northern Alaska depositional trough. Additional 

test wells were drilled on anticlinal structures in 

the foothills, an area that had been drilled extensively in the Pet-4 program, but only for shallow 

horizons. One test well was drilled in the overthrust 

belt near the front of the Brooks Range. Nearly all 

these test wells produced shows of oil or gas, but no 

commercial deposits were discovered. 

The congressional mandate to continue supplying gas to the Barrow community required drilling 

additional production wells in that area. Six wells 

were drilled, and four were completed for production. 

The third duty of the USGS was to complete 

cleanup of the debris from earlier work within or 

adjacent to the Reserve. In addition, all the sites or 

"areas of operations" of the current program, as 

defined in a memorandum of understanding 

(MOU) with the U.S. Bureau of Land Management 

(BLM), had to be rehabilitated and revegetated. A 

cleanup program was started by the U.S. Navy in 

1971 and was completed by the USGS in 1984. 

These sites have recently been returned to management by the BLM. 

The Lisburne No. 1 test well, located in the southern part of the 

N PRA, was spudded in j une I 979 and completed in j une I 980 at a 

total depth of 17,000 feet. 

Cl6 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
Summary of significant 

events in the history of 

petroleum exploration in 

Alaska 

The history of petroleum exploration, development, and production in Alaska reflects an odd mix 

of Government exploration and assessment, Government regulation and land management, oilindustry interest, and market fluctuations. Federal 

exploration in the NPRA was concentrated largely 

in the three periods 1923-26, 1944-53, and 

1974-82. In between, other events and publications influenced the course of petroleum development. The USGS had, and continues to have, a major 

role in this story. Some of the more significant 

events are: 

1901 - Industry began petroleum 

exploration in Alaska. 

1902-33- Oil discovered near seepages at 

Katalla; 154,000 barrels of crude oil 

produced. 

1910-20- Industrial activities slowed by 

Federal land withdrawals. 

1923 - NPR-4 established by Executive 

Order 

1923-26- First exploration ofNPR-4 by the 

U.S. Navy and USGS. 

(/) 30 I 

1-- 6 20 

~ 

3 10 w 

a: 

GEOLOGIC SURVEYS 

- Government activity 

D Industry activity u O c__ ____ _ 

1 

Geologic reconnaissance 

of NPR-4 

Creation of NPR-4 

1920-40 - Industrial exploration intensified in 

southern Alaska; no major 

discoveries. 

194 1 - USGS report on possible oil 

provinces in Alaska by P S. Smith, 

American Association of Petroleum 

Geologists ( AAPG) Bulletin. 

1951 - USGS report on possible future 

petroleum provinces by George 

Gryc, D. ]. Miller, and T G. Payne, 

2nd AAPG Symposium. 

1944-53- Pet-4 program. 

1953 - All Pet-4 data released in USGS open 

1957 

1958 

1959 

1960 

1963 

1964 

files. 

- Swanson River, Cook Inlet field 

discovered by the Richfield Oil Corp. 

- Alaska Statehood Act and Public Land 

Order 82 rescinded; USGS begins 

publication of series of professional 

papers on NPR-4. 

- USGS Bulletin by D. J Miller, T G. 

Payne, and George Gryc on possible 

petroleum provinces in Alaska. 

- ANWR established. 

- Industrial explo~;atory drilling begins 

on the North Slope near NPR-4. 

- USGS report on mineral and water 

resources of Alaska by W. W. Patton, 

Jr., and others suggests possible 

'friassic-Permian sandstone reservoirs 

under coastal plain. 

1968 Prudhoe Bay oil field discovered by 

the Atlantic Richfield Corp. 

1970 National Environmental Policy Act; 

USGS report on thermal effects of 

heated pipeline on permafrost by A. 

H. Lachenbruch has major alkct on 

design of the Trans-Alaska Pipeline. 

1971 - Alaska Native Claims Settlement Act. 

1974 - Arab oil embargo; U.S. Navy renews 

exploration in NPR-4. 

1976 - Naval Petroleum Reserves Production 

Act of 1976 (Public Law 94-258) 

transfers responsibility for the NPRA 

(formerly NPR-4 ) to the 

Department of the Interior; 

exploration program assigned to the 

USGS. 

1977 - Trans-Alaska Pipeline completed, and 

oil delivered to Valdez at the rate of 

1.2 million barrels per day. 

Exploratory drilling near Prudhoe 

Bay continues; additional discoveries 

made. 

1982 NPRA program terminated. 

1982-83 - Lease sales in the NPRA; industry 

begins geophysical surveys. 

1983-84 - Geophysical surveys permitted and 

begun in the ANWR. 

Su nmW1)' of fJetrolt'u 111 exploration on th e North Slojll'.fi·o/11 I 921! to 

1979 (modifiedfi"om Bird, 1981). 

Exploration of NPRA 

Creation of ANWR 

"Land freeze" on federal acreage 

"Land freeze" (P.L.O. 82) Alaska Statehood (native claims pending) 

THE NATIONAL PETROLEUM RESERVE IN ALASKA Cl7 

What are the 

geological, 

geophysical, and 

geochemical factors 

considered in 

petroleum 

exploration and 

resource assessment? 

Tilted sedimentary rocks of the Torok Formation form the backbone of 

east- west-trending ridges in the Arctic foothills. These sedimentary 

~ rocks are part of a thick deposit of sandstone and shale derived from 

the uplifted Brooks Range durzng Cretaceous ttme. Photograph by 

Darwin S. Braden. 

In the late 1800's, during the early days of 

petroleum exploration, test wells were drilled only 

near obvious surface oil seepages. However, as the 

demand for oil grew and the difficulty of finding it 

increased, it became evident that a better understanding of the origin and location of petroleum 

deposits was essential. This quest for knowledge 

led to many investigations, ranging from the 

molecular structure of oil, through computer analyses of sound waves in the Earth, to how far a sand 

grain must travel to become well rounded. The 

results of such studies form the foundation of our 

present knowledge of petroleum and dictate modern exploration strategy. 

We have learned that oil and gas are formed from 

the remains of microscopic plants and animals buried in sediment. Pressure and heat subsequently 

turn this organic material into oil and gas. For a 

valuable deposit to accumulate, porous rocks must 

be available to hold the newly formed oil and gas; a 

permeable layer must be sealed above by an impermeable layer to prevent escape, and a trap, such as a 

fold or fault, must be present to concentrate large 

amounts of oil and gas. 

Thus, an exploration program must include a 

search for: ( 1 ) rocks containing organic source 

materials, ( 2) porous rocks to form a reservoir, ( 3) 

impermeable rocks to serve as a seal, and ( 4) oil or 

gas traps or stratigraphic trapping features. Before a 

drilling program is undertaken, the geologist must 

study the geologic history of the area and evaluate 

whether conditions are right for an accumulation of 

oil or gas. Such studies include geophysical and 

geochemical surveys, and evaluation of source 

rocks, reservoir rocks, and structural or stratigraphic traps. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C19 
Geologic history 

In general, the geologic history of the NPRA 

corresponds to that of the North Slope. From Mississippian through lhassic time, most of the region 

was below sea level and consisted of a broad stable 

shelf The north border of this shelf ~as a large 

landmass, which supplied great volumes of sediment to the submerged continental shelf 

Theories abound concerning the origin of northern Alaska, but probably during Jurassic or Early 

Cretaceous time the Alaskan landmass rifted and 

pivoted around a point near the Mackenzie River 

delta. This rift created the Canadian Basin of the 

Arctic Ocean and caused the uplift of the Brooks 

Range mountain system. The northern source of 

sediment was thus eliminated, and a new sediment 

source was created-the Brooks Range to the 

south. 

About the same time as or shortly after the 

Brooks Range uplift, there was a broad subsidence 

of the lands immediately to the north that formed 

the submerged Colville Trough. This sedimentary 

trough was partly closed to the north by a relatively 

stable border called the Barrow arch. This elongate 

bowl, the Colville li'ough, rapidly filled with more 

than 6 miles of sediment derived from the newly 

formed and rapidly eroding Brooks Range. The 

trough was then uplifted, folded, and faulted during 

Cretaceous and early Tertiary time. 

Since the early Tertiary, basin filling and deformation of that fill have shifted northeastward, so that 

the thickest Tertiary sedimentary deposits are in 

the northeastern part of the North Slope and offshore. Earthquake epicenters just offshore from the 

ANWR and tilted Pleistocene terraces onshore indicate that deformation continues even today. 

SOUTH NORTH 

Arctic Aleske Basin CANADA 

CRATON 

LATE JURASSIC -EARLY CRETACEOUS 

BROOKS RANGE Sediments from 

Brooks Range _T ___ _ Sagging of continental 

MID-CRETACEOUS 

BROOKS RANGE 

The geologic evolution of northern Alaska is depicted in these four 

cross sections. They depict a widely held theory that a sea-floorspreading center split the stable Canadian craton and that the northern Alaska plate rotated southward and westward to create the Brooks 

Range, the Colville Trough, and the Barrow arch (modified from 

Rickwood, 1970). 

- Fra nklinian Paleozoic sediments 

- Ellesmerian Paleozoic and sediments 

Brookia n Mesozoic sediments 

Brook ian Cenozoic sediments 

. Oil and Gas 

The Canada Basin probably f ormed by rifting of the once-stable 

continental shelf of the Canadian craton, and then by pivoting 

approximately 67° about a point near the McKenzie River delta. 

What controls rift-zone locations is not fully understood. Possibly, 

molten magma deep within the Earth creates zones of weakness 

beneath the continents and oceans (modified f rom Tailleur, 1983 ). 

C20 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
Eras Periods 

QUATERNARY 

TERTIARY 

p~~~==- 40 __ _ 

r-------jt--- 60 ---

Dominant life forms 

Mammals h 

Grasses become abundant 

Horses first appear 

{---------+-~~~~+--68 70 __ -+----~----------~----~~ -4 Extinction of 

CRETACEOUS Dinosaurs 

JURASSIC Birds first appaar 

Reptiles 

TRIASSIC Many 

Dinosaurs first 1-------j,_ subdivisions-+--·""" ----1-----t------j----+.;..;..-';;;:;=.~=--i 

but not 

t--------1-differentiatedCAMBRIAN 

here 

PRECAMBRIAN 

CJ Brookian sequence 

CJ Ellesmerian sequence 

CJ Franklinian sequence 

--- Amphibia 

Marine 

Coal forming swamps 

Fish~ ~ First vanebrates 

appaar lfiahl 

invartebrates .-Jr Finot abundant fossil record 

• (marine invartebrates) 

' Primitive 

' A geologic column shows the divisions of time throughout the Earth ·s 

history. These divisions, based on the evolution and extinction of 

different life forms, also tend to reflect ma;or tectonic events around 

the world. Three North Slope sedimentary sequences, the Franklinian, Ellesmerian, and Brookian, correspond, respectively, to preMississippian metamorphic basement, sediment derived from the 

north, and sediment derived from the south. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C21 
Structural elements and 

stratigraphic sequences 

The present geologic framework of the NPRA is 

composed of three distinct major physiographic 

and structural provinces and comprises three stratigraphic sequences (related packages of sediment) 

From north to south, these physiographic 

provinces are: the Arctic Coastal Plain, the foothills, 

and the Brooks Range mountain system. These 

provinces generally reflect the structural elements 

from north to south: the Barrow arch and the Arctic 

platform, the Colville Basin, and the Brooks Range 

thrust belt. The stratigraphic sequences within the 

NPRA subsurface are separated into the Franklinian 

rocks of pre-Mississippian age, the Ellesmerian 

rocks of Mississippian to Early Cretaceous age, and 

the Brookian rocks of Early Cretaceous to Holocene age. 

The Franklinian rocks form the uneven basement 

of the Barrow arch and the Arctic platform. This 

platform dips regionally south from the Barrow 

arch and reaches its greatest depth beneath the 

Brooks Range front, where the overlying sedimentary pile is thickened by imbricate thrust faulting. 

The platform also dips gently east and west from 

the north-south-trending Meade arch, which 

bisects the NPRA. The diversity of structural trends 

in the basement suggests a complex deformational 

history. North of the Barrow arch, the Franklinian 

rocks of the Arctic platform dip beneath the Beaufort Sea shelf and form a series of block-faulted steps 

that descend into the Canada Basin. 

Uplift of the Barrow arch and the Fish Creek 

platform (a complementary structural high south of 

the Barrow arch) during mid-Cretaceous time created three unusual catastrophic structures. West of 

the Fish Creek platform, a deep submarine landslide 

of about I ,200-square-mile area was formed. Across 

the central segment of the Barrow arch, a submarine canyon, about 40 miles long and as much as 

5,000 feet deep-slightly smaller than the Grand 

Canyon-was eroded in Lower Cretaceous sandstone and shale and later backfilled with Upper 

Cretaceous shale. On the crest of the Barrow arch, 

near Point Barrow, is an unusual circular, faulted and 

uplifted feature called the Avak structure that probably also formed during mid-Cretaceous time. The 

core of this structure contains chaotic (strongly 

disrupted) rocks of Jurassic and Early Cretaceous 

age. The origin of the structure is unknown. 

Although it has the structural form commonly 

attributed to meteorite-impact craters, there is no 

evidence for high temperature and pressure, and no 

evidence of meteoritic material. The Avak structure 

is surrounded by small dome-shaped features. To 

the east and west, these features are sealed by the 

faulted and uplifted rim, trapping and forming the 

Barrow gas fields. 

In the subsurface, beneath the foothills and above 

the Arctic platform, is a southward-thickening 

wedge of sediment -the Brookian and Ellesmerian 

sequences. The younger Brookian rocks are 

deformed in a wrinkled-carpet pattern of east-westtrending thrust-faulted folds, whereas the older 

sequence below is relatively undeformed. 

The southernmost margin of the NPRA includes 

the north edge of the Brooks Range thrust belt. This 

area contains sedimentary rocks that are folded and 

faulted into imbricately stacked thrust sheets. 

These thrust sheets are believed to represent largescale tectonic transport and crustal shortening by 

the underthrusting that formed the Brooks Range. 

The oldest stratigraphic sequence, the Franklinian sequence, consists mostly of metamorphosed sedimentary rocks that are complexly 

deformed and, in some places, intruded by granite 

and other types of igneous rock. These rocks form 

the Arctic platform and the basement beneath the 

Colville 'frough (as far as we know) 

The Ellesmerian sequence in the NPRA and Prudhoe Bay area includes sedimentary rocks of both 

marine and nonmarine origin that were derived 

from a northern continental source. This sequence 

is thickest to the north of the center ofthe Colville 

'frough. The early Ellesmerian rocks consist of a 

wide array of nonmarine coal-bearing sandstone, 

shale, and conglomerate of the Endicott Group, 

overlain by a blanket of marine-shelf limestone, 

C22 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

dolomite, and shale of the Lisburne Group. MidEllesmerian strata include a sheetlike package of 

mostly silty and sandy marine-shelf sedimentary 

rocks andl some limestone of the Sadlerochit Group, 

the Shublik Formation, and the Sag River Sandstone. 

Late Ellesmerian strata are mainly deeper water 

marine shale and mudstone of the Kingak Shale and 

the pebble shale unit. Although these shale units 

and their associated sandstone and siltstone beds 

are generally believed to have been deposited in a 

shallow marine-shelf setting, they have some of the 

characteristics oflarge fans deposited in a relatively 

deep basin. 

The Brookian sequence, of Early Cretaceous to 

Holocene age, consists mainly of deposits derived 

from the rising Brooks Range and dumped into the 

Colville 'frough. Each successive sedimentary unit 

prograded northward and eastward across the 

Arctic platform and eventually overtopped the Barrow arch. The upper Brookian rocks of the 

Nanushuk and Colville Groups are delta-plain sandstone and shale-marine in the east and nonmarine 

and coal bearing in the west. 
,,.. 

,,. 

70' 

68' 

\ 

Geologtc and structural nmp of the NPRA, showing the physiographic provinces, the Arctic Coastal Plain, the Foothills fold belt, 

the Brooks Range, and the surface distribution of Ellesmerian and 

Brookian rocks. The older Franklinian rocks do not crop out in the 

N PRA but are f ound farther south in the Brooks Range. The degree 

and complexity of folding increases from north to south. Large gentle 

f olds beneath the Arctic Coastal Plain and part of the northern 

foothills form broad basins and wide arches where oil and gas may be 

trapped and held. 

0, 

I 

\ 1 

152' 

- ......., --

Ellesmerian 

O arookian 

• Catastrophic structures 

• T est w ell locations 

--+-- Plunging anticline 

--+-- Synclinal basin 

Smaller fold features 

40 MlES 

t-r'l' ,,-,c,-, ---'---' 

.eo n o.:TERS 

, ... 

Synclinal basin 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C23 
Subsurface geology 

Geophysical surveys 

Geophysical prospecting supplies important 

data about the subsurface without drilling a well. 

Three geophysical methods or surveys were used 

during the study of the NPRA-gravity, magnetic, 

and seismic reflection. Gravity surveys measure the 

Earth's gravitational field, which is modified by the 

thickness, variation, and distribution of rock types 

in the Earth's crust. Very slight variations in the 

gravitational field are commonly related to changing subsurface conditions and may indicate a 

deeply buried fault or anomalous body of rock. 

Magnetic surveys measure the Earth's magnetic 

field. Variations in this field indicate the presence of 

rocks in the subsurface that have high or low magnetic properties. Because most sediment is nonmagnetic, this survey provides information mainly 

on the composition of the underlying basement 

rocks. Seismic-reflection surveys are based on an 

analysis of sound waves artificially generated in the 

Earth and then reflected from various rock layers 

back to the surface. All three methods gather 

remotely sensed data; that is, geologic interpretations about the subsurface are based on indirect 

evidence-the actual rocks have not been seen. 

Of these three methods used in the NPRA, the 

data from seismic-reflection surveys are the most 

specific, are quantifiable, can be corroborated with 

drilled wells, and generally (or if structure is not 

too complex) provide a clear visual representation 

of the subsurface in the form of a cross section. This 

method, however, is also by far the most expensive 

of the three. Gravity data, in contrast, were collected by the seismic surveying crews for only a 

small additional cost. Magnetic data were collected 

by towing a magnetometer behind a low-flying airplane. This method was used mostly during the late 

1940's and has not been a major part of the recent 

USGS NPRA project, although in selected areas very 

low level aeromagnetic surveys were flown. Their 

purpose was to detect near-surface magnetic anomalies related to leaking oil or gas. 

Seismic profiles are produced by setting off a 

small charge of explosives in a shallow drill hole 

(rarely more than 100 feet ~eep) or by large 

vibrators that send shock waves or "acoustic signals" deep into the subsurface. These shock waves 

travel through sedimentary-rock layers and gradually lose energy with depth. At certain boundaries 

where these rock layers have different acoustic 

properties, some of the energy of the shock waves is 

reflected back to the surface. This returning acoustic signal, or echo, is received at the surface by a 

series of geophones-sensitive detectors spaced 

along a straight line-and electronically transferred into a printed seismic record. 

Seismic "trains'' work during the winter months and gather data 

about the subsurface rock layers. Photograph by john Schindler. 

Inside the seismic-recording trailers are rows of computer monitors, 

magnetic tapes, and recorders that plot the actual profile. Photograph 

by jeep Johnson. 

C24 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
Explosives are placed into drill holes ... . .. . then detonated in sequence. The sonic shock waves from the explosion travel through the subsurface and are reflected back to the 

surface. Photographs by J ohn Schindler. 

Cartoon cross section of a seismic survey. Sensitive "geophones" 

receive the reflected sonic shock waves and transmit data to the 

recording machines. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C25 
The density and lithology of the subsurface rocks 

affect the velocity of the seismic shock waves and 

must be considered when correlating the seismic 

records with the drilled-well data. In general, these 

shock waves travel faster in dense rock. Velocities in 

homogenous rock layers generally increase with 

depth because of increasing compaction of the sediment. For example, in the Colville Group, the 

Nanushuk Group, and the Torok Formation, the 

average shock-wave velocity regularly increases 

from 8,000 feet per second at a subsurface depth of 

1,000 feet to about 13,000 feet per second at a 

depth of 8,000 feet. Layers of rock with large 

velocity differences will cause a strong echo, 

which, in turn, will produce a strong signal on the 

seismic record. For example, the low-velocity pebble shale unit and the relatively high velocity Sag 

River sandstone and Shublik Formation produce 

strongly reflecting events, many of which can be 

traced over large distances in the NPRA. 

INIGOK NO . 1 

(/) 

0 

2 

0 .0 

1.0 

8 2 .0 w 

(/) 

~ 

4 .0 

5 .0 

VELOCITY, IN FEET PER 

SECOND X 1000 

'" 5 

C26 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

Seismic-reflection profile showing rock structures nearly 5 miles into 

the Earth. This profile tran.sected the lnigok well. Different reflections 

in the seismic record are correlated with rock layers from the well. The 

inset is a log of the shock-wave velocity f or the different rock layers 

penetrated by the well. 

Colville Group -nonmarine and marine 

shale with coal and sandstone beds 

Nanushuk Group -marine sandstone 

with shale beds 

Torok Formation -prodelta shale with 

turbidite sandstone of base 

Kingak Shale -distal prodelta organic 

shale and siltstone 

Sag River sandstone, Shublik Forma -

tion, and Sadlerochit Group 

Lisburne Group -shelf limestone and 

dolomite 

Endicott Group -nonmarine conglom -

erate sandstone, and shale. Coal 

bearing 

Argillite 

3 MILES 
The seismic surveys were made along a series of 

straight lines that intersected at approximately 

right angles, forming a grid. Each seismic crew was 

supported by a train-a series of tracked vehicles 

on which were mounted the seismic recording 

equipment, drills, hole-loading equipment, and so 

on. The train also had a series of trailers mounted 

on sleds, which contained kitchen, mess hall, 

bathroom, sleeping facilities, supplies, and an office 

12', 

70' 

68' 

160' 

\ . ' 't :. \ 

"'Si:l.ASKA: \ J \.~ - ._r ·, 

25 G"'"''"' ,.J>" LOCATION MAP \t 

sEA 

c.._, 

/ 

( 

in which the field records were inspected and crew 

records were maintained. The crews operated 

about 5 to 6 months out of each year, from 

December until late April or early May, and were off 

the tundra before spring thaw in mid-May. 

During the 10-year period of the Pet-4 program, 

the U.S. Navy acquired about 3,300 line-miles of 

seismic-reflection data; and from 1974 to 1982, the 

Navy and the USGS together acquired about 13,200 

_____ 1974- 80 Seismic lines 

50 MILES 

l-o-1 -',1 1-+.,.l.l.l r-1 -'--'1 

50 KILOMETERS 

line-miles of data. The total 16,500 miles of seismic 

information and the resulting interpretations have 

been released to the public, have enlarged the 

· exploration data base, and have contributed greatly 

to our general knowledge of northern Alaska. 

Laying cable with attached geophones. Photograph by j eep j ohnson. 

Securing geophones into the snow. Photograph by j eep J ohnson. 

Nearly 15,000miles of seismic data was collected from JcJ74 to 1982. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C27 
Exploratory wells 

The modern exploratory well is the ultimate 

device for gathering detailed information about 

subsurface rock layers. Its main purpose, of course, 

is to discover oil and gas; but, in addition, factual 

information gathered on the deeply buried rocks is 

extremely valuable, and analysis of such information may suggest future prospects. 

The main components of a drill rig are the mast, 

engines, drawworks, drill pipe, and mud system. 

Within the mud system, specially formulated drilling mud is continuously pumped down the interior 

of the drill pipe; the mud leaves the bit in the form 

of a jet and returns to the surface. A properly controlled mud system is of critical importance; it is 

designed to cool and lubricate the drill bit, support 

the sides of the hole, keep the well under control, 

reduce friction on the drill string, and remove rock 

particles. These rock particles, known as "cuttings," 

range from sand to fingernail size and are sampled 

periodically at the surface during drilling. Automated instruments continuously monitor the mud 

system for evidence of oil and gas shows. 

Drill rig allhe lnigok No. I test well. This well was the second deepest 

drilled in the Reserve. Photograph by J eep j ohnson. 

C28 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
When significant shows of oil or gas are found, or 

whenever special rock layers are discovered, drilling may be stopped, and a core of rock taken, 

usually as a 10- to 30-foot-long section. Rock cores 

provide a large enough sample to measure two 

important reservoir properties-porosity and permeability. Cores also are used for geochemical analyses and commonly reveal sedimentary structures 

that provide important information for unraveling 

the ancient depositional history. 

Before the borehole is cased, the well is surveyed 

with wireline logging devices that are encased in 

long metal tubes and lowered into the well. These 

devices measure the electrical, radioactive, and 

acoustic properties of the rocks to determine rock 

types, porosity, and fluid content. The logs of these 

measurements are then correlated and compared 

with lithologic data from the cuttings and core 

samples, and with seismic data, and are analyzed to 

determine the productive potential of oil and gas 

horizons. 

Geologist examining fresh core samples. If a petroleum-rich layer is 

detected, a core of the rock is generally taken. Study of a core is the best 

way the geologist can detennine the sedimentary textures. Photograph 

by j eep j ohnson. 

Computers monitor the drilling process and store the data. Photograph by j eep J ohnson. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C29 
Kelly 

In all wells, a detailed casing and cementing program is preplanned for specific depths and specific 

purposes. Casing is used to prevent cave-ins, migration of fluids from one rock formation to the other, 

and contamination of any oil and gas that are produced. The casing also serves the important function of preventing downhole sloughing of pieces of 

shallower rock formations that could contaminate 

the mud system and produce an inaccurate picture 

of the subsurface rock types. 

If good oil or gas shows are identified, a drill-stem 

test is run to determine how much petroleum will 

flow from a specific depth. All fluids and gases 

trapped in the subsurface are naturally pressurized, 

and the drill-stem test isolates a specific rock layer 

C30 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

and measures the flow rate and pressure of these 

fluids and gases as they are released into the drill 

pipe and up to the surface. These tests help locate 

the potential petroleum-bearing layers. 

The cost of drilling exploratory (wildcat) wells 

in the Arctic is 5 to 10 times greater than in the 

"Lower 48"; a single test well may cost more than 

$100 million. The anticipated return must be considerably greater to attract investment capital. 

Thus, discovered deposits must be much larger in 

the Arctic than elsewhere to warrant development. 

An oil reserve of a few tens of millions or even a few 

hundreds of millions of barrels may not be 

developable profitably in the Arctic. 

Diagram of a mud system. Mud is an essential component used in 

drilling wells. For the exploratory wells in the NPRA, automated 

analysers continu ously monitored the mud for the presence of oil and 

gas. 

Soft-rock drill bit. The type of drill bit used depends on the type of rocks 

being drilled. For rocks of the Brookian and part of the Ellesmerian 

sequences, soft-rock drills without embedded industrial diamonds 

were generally used. Photograph by j ohn Schindler. 
lnigok drill mast shows the mwi hose (center), drill pipes (right), and 

the swivel (yellow )---11 type of universal joint that allows the drill 

string lo turn while mud is passing through it. Photograph by j eep 

J ohnson. 

Wireline logging devices lowered into the lest hole or borehole providt 

additional data for determining the porosity , fluid types, rock typts, 

grain sizes, and seismic velocities of the rocks in the subsurface. 

2000 

4000 

6000 

8000 

~ 

.. 10.000 x 

1;: 

:!: 

12.000 

14.000 

16.000 

18,000 

20,000 

20 in . at 2594 ft K.B. 

20 in ., 133 lb casing 

13 3 /8 in. at 8286 It K.B 

9 5/8 in . and 9 3 /4 in 

at 12,283 It K.B. 

9 5 /8 in., 53.5 lb casing and 

9 3/4 in ., 59.2 lb casing 

Down sQueezed liner lap w / 

Plug No.3. 16,600 ft to 1 5, 

7 5/8 in . liner 11 ,818 ft to 

17.432 ft K.B 7 5/8 in ., 39 lb 

casing 

6 1/4 in . hole to 20, 1 02 It K.B 

T .M .D. (20,004 .76 It T .V .D .I 

Abandonment marker 

EXPLANATION 

~ Cement holding casing to 

• well hole 

- Plug to prevent vertical 

fluid contamination 

- Mud seal to prevent the 

f low of fluids in the for -

mation into the well hole 

INIGOK TEST WELL NO. 1 

2713 ft FSL and 1843 ft FWL 

Section 34, T . 18 N ., R. 5 W ., U .M 

HUSKY OIL N .P.R. OPERATIONS 

NATIONAL PETROLEUM RESERV E IN ALASKA 

WELLBORE SCHEMATIC 

Detailed rasing mul cnne 11 ling progm mjl"llm a 11 offir ia! I' ngi neeri ng 

report of the abandoned l nigok les/we/1. The casing pipe is remellll'rl 

lo the sides of tlu' borelwle. The pipe is also su.<finidnl a/the !ofJ oft he 

well in case the cement should ./(1il to hold (morlijinl Fmn H usky, 

1983) 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C3l 
Subsurfuce stratigraphy 

The sedimentary rocks in the NPRA subsurface 

constitute a 6- to 7-mile-thick wedge of sandstone, 

shale, and limestone-debris that was deposited on 

ancient flood plains and in marine basins during the 

past 350 million years. These rocks form the 

Brookian and Ellesmerian sequences; beneath them 

lie older basement rocks of the Franklinian 

sequence. South of the coastline and the subsurface 

Barrow arch, few exploratory wells were drilled to 

depths that penetrated the Franklinian rocks 

because of the low economic potential of these 

older rocks and the cost and difficulty of drilling 

deep test wells. 

To complete the basic stratigraphic study at a 

wellsite, the different rock layers are distinguished 

by using the cores, cuttings, and wireline-Iog 

response. Paleontologists determine the rock's age 

by identifying the contained microscopic fossils, 

the remains of plants and animals. Most common 

are pollen, spores, foraminifers (one-celled animals), and algae. Large fossils, like seashells, are 

generally destroyed during drilling, and so microfossils are most commonly used. After the ages and 

rock types are determined, a "stratigraphic column" is drawn up for each wellsite. With this information in hand, stratigraphic relations and changes, 

such as thinning or thickening and lithologic variations of a certain layer, can be compared and correlated from well to well. Geologists then use the 

seismic records to predict the configuration and 

composition of the subsurface rocks between the 

wells. 

C32 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

Ancient marine plank tons (dinoflagellates) and plant sfJores{rolll the 

pebble shale unit. From left to right: Oligosphae ridium complex , 

X 450; Deltoidospora sp., X 500; and Lycopodium sporitcs 

sp. , X 800. These extinct f orms of plant spores and planktons, 

preserved in the pebble shale, helped to determine that the age of the 

sediment is Early Cretaceous. Photograph courlesv of Rugrr Witmn. 
Small rock "cuttings" brought to the surface by the circulating drilling 

mud are periodically sampled and analysed. Photograph by J eep 

j ohnson. 

SEQ. 

z 

c( 

:;;;: 

0 

0 

85 

AGE 

If) 

:::> 

0 

w 

u 

c( 

1-

w 

cr 

u 

UNIT 

AND 

General stratigraphic column of N PRA rocks. 

DESCRIPTION 

Sand, silt, gravel. and clay , shallow marine and rine 

Sediment derived from the Brooks Range terranes prograded northerly and easterly to fill the Colville Basin . 

When the basin was filled with four miles or more of 

sediment the ancient delta system overtopped the 

Barrow arch and prograded northerly onto the Beaufor-t 

shelf . 

Sediment derived from a northerly source . Generally the 

sediments coarsen and the layers thin from bottom to 

top. 

Basal part of the Endicott Group consists of non-marine 

coal-bearing sandstones and shales deposited in down -

faulted basins on the Arctic platform. 

Low - grade metamorphic rocks 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C33 
Source rocks 

Field and laboratory studies indicate that naturally occurring oil and gas are the products of 

heated organic matter, except for biogenic gas, 

which is formed by bacterial action. These studies 

show that certain types of organic matter are necessary, that these types must occur in certain minimum concentrations, and that they must be heated 

to a certain threshold but not too far beyond, or the 

oil and gas will be destroyed or "burned up." A 

source rock is a body of rock from which oil and gas 

can be derived. Petroleum geologists can improve 

the chance of finding oil and gas by studying possible source rocks before an exploration program is 

begun. If no organic-rich source rocks are 

observed, then the prospects of finding oil or gas in 

that area are diminished. However, oil and gas can 

migrate great distances, and so that criterion must 

be used with care, and the regional geology must 

also be considered. 

Assessment of source-rock potential requires 

that four major questions be answered: ( 1) Is there 

a sufficient amount of organic matter in the rocks? 

( 2) What kind of organic matter is present? ( 3) Has 

the thermal history of the area been appropriate for 

generating oil and gas and subsequently appropriate for preserving it? and ( 4) Have oil and gas 

actually been generated? These four questions are 

answered by observations and by carrying out several types of geochemical analyses in the laboratory 

that evaluate the overall petroleum potential of the 

rocks. 

Organic material must be heated to a certain degree to generate 

hydrocarbons. This cross section shows the depth and structural 

conditions under which organic material might be transformed into 

oil or gas (modified from Bird, 1981). 

The amount of organic matter in the rocks is 

determined by an analysis of their organic-carbon 

content ( OCC); organic material, which originated 

from either terrestrial or marine organisms, is measured in weight percent. The OCC by itself indicates the organic richness of the rocks but gives no 

clue as to the presence or generation of oil and gas. 

OCC's ofO.S to 2.0 weight percent indicate a possibly fair source rock, and of greater than 2.0 weight 

percent a possibly good to excellent source rock 

The kind of organic material present is determined by studying samples under a microscope 

and by chemical analysis. Marine organic materials 

produce mostly oil, whereas terrestrial materials 

produce mostly gas. Thus, from knowledge of the 

kind of organic material present in an area, the type 

of petroleum most apt to be found can be predicted. This determination may be of critical importance to the economics of production and 

marketing. For example, there is no gas pipeline out 

of the North Slope and thus no way of economically 

transporting gas to market. 

The thermal history of the basin determines 

whether the rock has been heated to the appropriate degree and for the right length of time-not too 

long and not too short-for the generation of oil 

and gas. The thermal history is disclosed by several 

methods. One type of qualitative analysis is the 

SOUTH 

A 

NORTH 

A ' 

0 

2 

10 

t:;:; 

~ 4 

~ 

:r: ,_ 

fb 

CJ 

20 6 

8 

30 

10 

EXPLANATION 

• Under mature for oil (Biogenic gas) 

• Thermally mature for source rock 

• Over mature for oil, mature for gas 

South to north cross section : Potential oil source rocks shown in red 

C34 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

Cl) 

cr 

w 

,_ 

w 

:::;: 

g 

;;;:: 

~ 

:r: ,_ 

c.. 

w 

CJ 
" thermal-alteration index," based on the progressive color change, or darkening, of specific fossil types with increasing temperature. 

The most recent studies show that four marine 

shale units have the appropriate complement of 

parameters to be considered as a source for oil: the 

Torok Formation, the pebble shale unit, the Kingak 

Shale, and the Shublik Formation. These rocks are 

thermally immature along a relatively narrow zone 

parallel to the northeast coastline of the NPRA (the 

Barrow arch), but as they thicken toward the south 

and become more deeply buried, the rocks become 

more mature and have produced oil and gas. The 

richest but thinnest source rock, on the basis of all 

these analyses, is the 120-million-year-old pebble 

shale unit. 

Whether oil and gas have actually been generated 

can be answered by observation. During drilling, 

many oil and gas shows were penetrated in each of 

these formations and related reservoir rocks. These 

shows lead to the conclusion that oil and gas were 

generated. However, they may not be present in 

sufficient amounts to form economic deposits for 

some reason, such as the absence of traps or migration of the oil and gas to other areas. 

Photomicrographs of thin sections of the Torok Formation, the pebble 

shale unit, the Kingak Shale, and the Shublik Formations-{lll possible source rocks in the NPRA. Organic material shows up as black 

splotches. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C35 
Reservoir rocks 

Any porous rock layer with interconnecting 

open spaces or holes is a potential petroleum reservoir. The proportion of open space is called porosity, measured in volume percent. Thus, 25 percent 

porosity means tha one-fourth of the rock consists 

of pore space. The interconnectedness of pore 

spaces, which provide the paths for circulating fluids, is referred to as permeability, the ability to 

transmit fluids. The degree of porosity and permeability is the result of the depositional environment, the history of burial and consolidation, and 

secondary effects, such as fracturing and etching. 

Examples of sediment that may form good reservoirs are well-sorted beach or channel sand and 

72' 

70' 

167• 

EXPLANATION 

'* Oil fields 

• Gas fields 

ARcTIC 

158' 

limy sand derived from broken fragments of coral 68• 

reefs. Hard and brittle rocks may become porous by 

fracturing or etching by circulating fluids, so that 

open spaces are created. 

Predicting which rock layers may be good reservoirs is one of the most important factors in 

petroleum exploration. Petroleum geologists spend 

considerable time and effort studying modern sedimentary or depositional environments as a key to 

understanding ancient environments as represented by the rock sequence. Models and criteria 

are organized to identify paleoenvironments and 

thus to predict the reservoir properties of the rocks 

that have been formed. The position and configuration of ancient sedimentary-transport systems are 

also important in prediction. Coarse, well-sorted 

sandy and cobbly sediment derived from an ancient 

river system or shoreline may grade laterally into 

finer sand from an offshore bar, through muddy 

marine-shelf deposits, eventually to an organic-rich 

deep-water clay. As the shorelines and rivers move 

and change, different kinds of sediment are deposited, one on the other, to form a sequence with a 

complex sedimentary history. A specialist, a sedimentologist, may spend an entire career studying 

these sequences to predict where good reservoir 

rocks may be found. 

Locations of known petroleum reservoirs in the N P RA (modified from 

Bird, 1981). 

STRATIGRAPHIC TRAP 

C36 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

149' 140' 

0 C E A N 

STRUCTURAL TRAP 
Large chevron folds in the Torok Formation exposed along a riverbank in the foothills. These folds are associated with a much larger 

scale folding event that included broad anticlines and synclines 

several miles across. The large- scale anticlines were targets for many 

of the exploratory wells. Photograph by Irvin Tailleur. 

To form an oil or gas deposit, the reservoir rock 

must be situated in some form of trap, commonly a 

fold or anticline. Oil and (or) gas migrate into this 

structure and are trapped, provided the reservoir is 

sealed by enclosing rocks or structures. The sealing 

rock may be an impermeable clay or shale, or a fault 

may seal off the deposit. Because most reservoir 

rocks are naturally water saturated, the oil and gas 

rise or float to the top of the trapped accumulation 

to form the classic configuration of a layer of water, 

then of oil, and finally a gas cap. The determination 

of these layers, their extent and location, are important in estimating the size of the deposit and its 

potential production. 

The uneven packing of sedimentary grains forms natural pore spaces. 

Migrating oil may fill these spaces and, if sealed above by an impermeable layer of rock, may remain in place for millions of years. 

Preserved current ripples in the Fortress Mountain Formation that 

formed on an ancient ocean floor near the newly uplifted Brooks 

Range. Current ripples reveal the flow direction of ancient oceanbottom currents, which can indicate the direction to possible reservoirs. Photograph by Irvin Tailleur. 

Dolomite sample from the Lisburne Group reveals tar trapped in pore 

spaces. The pore spaces, or "vugs," were once fossilized fragments of 

seashells that have since been dissolved, creating a seconda.ry porosity. 

Photograph by William W. Chamberlain. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C37 
Within the NPRA, good reservoir rocks are relatively scarce in comparison with the adjacent Prudhoe Bay area. However, reservoir rocks containing 

small or residual accumulations have been found in 

rocks ranging in age from Mississippian to Cretaceous. Significant oil accumulations have been 

found within the Nanushuk Group of Cretaceous 

age at Umiat, Simpson, Fish Creek, and Umiat, and 

gas accumulations at Umiat, Gubik, Meade, Simpson, Wolf Creek, and East Umiat. The Barrow gas 

deposits are in reservoirs in the Kingak Shale of 

Jurassic age. At the W T. Foran and J. W Dalton test 

wells along the Arctic coast, residual hydrocarbons 

were found in rocks of Mississippian and Permian 

age, coeval with the reservoir rocks in the Prudhoe 

Bay area. 

Peard e 

e Kugrua 

South MeadeO 

e Tunalik 

Kaolak e 

o Meade 

Awuna e 

0 Topagoruk e 

e East Topagoruk 

lkpikpuk• West Fish Creek• 

•North lnigok 

Oumalik 

• e East Oumalik 

e Square Lake 

Titaluk e 

Knifeblade e 

Lisburne e 

C38 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

Gubik 

Rock Formation 

Nanushuk 

Colville 

Nanushuk 

Torok 

Lisburne 

Nanushuk 

Nanushuk 

Nanushuk 

Nanushuk 

Nanushuk 

Pebble Shale unit 

Nanushuk 

Maximum flow rate during 

drill stem test 

Small oil recovery 

Up to 8 MMCF/day 

1.1 MMCF/day 

.08 MMCF/day 

.7 MMCF/day 

6. 7 MMCF/day 

3.0 MMCF/day 

Up to 1 20 bbls/day 

Up to 450 bbls /day 

6.0 MMCF/day 

2.3 MMCF/day 

1 .1 MMCF/day 

Barrow No. 19, No. 14 Kingak 7 MMCF/day (production rate) 

The most productive oil well in Prudhoe Bay is listed as producing 16,000 bbls/day 

- however most wells produce between 3 ,000 and 5 .000 bbls/day. 

MMCF/day = million cubic feet per day. 

bbls /day=barrels per day. 

Drill-stem tests were made at several wells in the N P RA. If oil and gas 

shows were detected, a test was made at a specific depth to measure the 

possible flow rate and pressure of the oil or gas. These tests verify the 

presence of oil or gas reservoirs but do not detennine the total amount 

of petroleum that might be trapped. Map shows locations of 28 wells 

drilled during the most recent program. 
C1·ude-oil seepltges nrar Cape Simj).\011. Some of the jint exjJ!orn., 

described thes!' serfis, and the Na/h1es used !Ill' tor asji1rl. l'holo[!;lil ph 

by George Gryc. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C39 
How were oil and gas 

resources estimated? 

Example of a play-analysis data form, annotated to show the two 

fundamental questions asked in any petroleum-resource assessment. 

Although estimates of oil and gas resources were 

regarded as probably the most important economic 

contribution to studies of the NPRA, the Naval 

Petroleum Reserves Production Act of 1976 (Public 

Law 94-258) required much more. To satisfy all 

the requirements of the act, an interactive computer-based economic model was constructed. 

Estimates of the amounts of yet-to-be-discovered oil 

and gas in the NPRA were basic to this economic 

model. The model simulated the economic consequences of various development plans to satisfy 

the act, which specifically required a study to determine the best overall procedures for the development, production, transportation, and distribution 

of any petroleum resources in the Reserve, and the 

economic and environmental consequences of the 

various procedures. The following paragraphs 

briefly describe the method of arriving at the estimates that were provided to the economic model. 

The reader interested in more details should consult the report by the U.S. Department of the Interior, Office of Minerals Policy and Research Analysis 

(1979) 

OIL AND GAS APPRAISAL OAT A FORM 

EVALUATOR: U.S. Geological Survey 

DATE EVALUATED:-------------

PLAY NAME: ---------

REVISED: -----------------

C40 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
The traditional USGS method of estimating oil 

and gas resources, though successfully applied to 

two assessments of the Nation's resources within 

the past decade, did not supply the input required 

by the economic model constructed for the NPRA. 

A survey of other established methods turned up 

the play-analysis technique. The method employed 

in the NPRA was a modified version of this technique, developed by the Geological Survey of Canada to assess Canada's oil and gas resources. "Play" 

is an oil industry term describing an area where the 

prospective oil or gas deposits have similar characteristics, such as the same reservoir rock or a similar 

type of trapping mechanism. 

In the play-analysis method, geologists make 

judgments on the geologic factors necessary to 

form an oH or gas deposit, and a computer gener- -

ates the estimates. This arrangement utilizes the 

geologist's expertise with geologic factors and the 

computer's expertise with manipulation of numbers. 

The geologist's judgments are recorded on a data 

form. An example of this form is annotated here to 

show how it answers the two fundamental questions asked in any assessment: ( 1) are there any oil 

or gas fields in the area and, if so, ( 2) how much oil 

and gas is present? 

To answer the first question, geologists enter on 

the form probability judgments as to the 

favorability of the several factors necessary for an 

oil or gas deposit. These judgments are recorded on 

the upper half of the form (play attributes and 

prospect attributes) By multiplying all the probabilities together, an answer is obtained-the probability that oil and gas deposits are present. Oil 

companies use the term "risk"-the chance of 

failure-which is simply this probability minus 

one. 

The lower half of the form addresses the second 

question. Here, geologists estimate a range of values 

for each of the five geologic factors needed to calculate the volume of oil or gas in a deposit. 

In the NPRA assessment, a committee of 7 

geologists established and assessed 17 separate 

plays. In assessing each play, the committee 

METHOD OF REPORTING ASSESSMENT RESULTS 

~ 100 ------~~r:~----~~--~----~~~~~==~~ w 

u 

a: 

w 

a.. 

~ 

w 

u 

z 

w 

a: 

a: G SO r-----------i-~~------~~--~--~~----~~~-1 

u 

0 

u. 

0 

~ 25 r-----------i-----------~--~~~~~------~--~ ::; 

iii 

<i 

0 "' 

a: 

a.. L------J-----------~---------- ~--~~~~ 0 10 100 

VOLUME OF UNDISCOVERED RESOURCES 

Probability curve showing the decreasing probability of petroleum 

occurrences with increasing volume of undiscovered oil or gas. 

reviewed extensive data summaries, representing 

many months of work by a team of geologists. A 

typical data summary for a play consists of several 

types of maps, cross sections, charts, and graphs. 

Such comprehensive data summaries are essential 

for an efficient and reliable assessment. 

The computer, running a program called RASP, 

generates the resource estimates by selecting and 

combining one possible value for each hydrocarbon volume factor (from the lower part of the 

form) to give one estimate for the oil and gas 

resources of the play. This process is repeated 3,000 

times for each play in the assessment. The result is 

3,000 different answers reflecting various combinations of values randomly selected from the form-a 

procedure known as a Monte Carlo simulation. For 

each play, these answers are lined up from smallest 

to largest, and statistical values, such as the average, 

are calculated. From these calculations, the range of 

answers can be summarized on a single probability 

curve, such as the one shown here. By now, it 

should be clear that no single answer is possible to 

the question of how much oil and gas are present; 

instead, an infinite number of answers are possible, 

each with its own confidence level. For example, 

from the curve illustrated above, one may expect a 

50 percent chance that at least 1 million barrels of 

oil are present. Larger amounts of oil correspond to 

lower probabilities-that is, less confidence that 

those amounts are present-and smaller amounts 

of oil to higher probabilities, or more confidence 

that at least those amounts are present. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C4 l 
For all 17 plays in the NPRA, the amount of 

undiscovered inplace oil is estimated at 0.82 billion 

barrels at a 95-percent probability and 15.4 billion 

barrels at a 5-percent probabilty, for an average 

value of 5.97 billion barrels. The total amount of 

undiscovered inplace natural gas is estimated at 2.4 

trillion cubic feet at a 95-percent probability and 

27.2 trillion cubic feet at a 5-percent probability, for 

an average value of 11.3 trillion cubic feet. The 

contribution of each play to the average values for 

oil and gas is shown graphically here. 

Although use of a computer and a complex data 

form give the illusion of better or more accurate 

estimates, they may, in fact, be no better than estimates by much simpler methods. Only time and 

continued exploration will tell the "correctness" of 

the estimates. What this method does, however, 

which many others don't, is to guarantee a systematic consideration of each of the factors necessary for an oil or gas deposit, to record these 

considerations, and to report the estimates of volumes and pool sizes in terms of probabilities. 

C42 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

i 

i 

i L.-.. ___ -............_ 

ESTIMATED AVERAGE AMOUNT OF NATURAL GAS 

IN PLACE FOR ALL OF NPRA 

11.3 TRILLION CUBIC FEET 

'" ' ~-"j 

The proportion of the average amount of natural gas contributed by 

each of the 17 plays assessed (shaded area). 
'-..r -~ -- , 

""- ' '--"--.___1 

ESTIMATED AVERAGE AMOUNT OF OIL 

IN PLACE FOR ALL OF NPRA 

5.97 BILLION BARRELS 

The proportion of the average amount of oil contributed by each of the 

17 plays assessed (shaded area). 

/ r __ / 

"-,_, i ., _~ 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C43 
What were some of the 

geotechnical, 

engineering, and 

environmental 

considerations in the 

exploration and 

development of the 

NPRA? 

Petroleum exploration in a remote wilderness 

area, such as the NPRA, requires not only consideration of the geologic factors but also special attention to climatic, geographic, and environmental 

aspects. The congressional mandate specifically 

called attention to environmental and cultural considerations and required studies (Public Law 

94-258, sees. IOS(a), IOS(b)) of other resources, as 

well as of alternative management procedures and 

their economic and environmental consequences. 

These studies were completed by the U.S. Department of the Interior and submitted to the Congress 

as scheduled. 

In the light of these special mandates and the 

Arctic wilderness setting, the USGS and the BIM 

agreed on procedures to be followed to accomplish 

the exploration with minimal impact on the 

environment. These procedures required careful 

and thorough advance planning and monitoring in 

accordance with prescribed environmental stipulations. The final reports by the operating contractors describe these actions in detail, and only a 

few highlights are included here. 

Surficial materials 

Surficial deposits in the NPRA consist mostly of 

fine-grained deposits-day, silt, and sand. Gravel, 

the material required for constructing all-season 

drill pads, airstrips, and roads, is scarce and is confined to riverbeds along the slopes of the Brooks 

Range, the Colville River bed, and a few areas along 

the Arctic coast. In some places, long hauls were 

required to bring in satisfactory construction material; the same gravel may have been used repeatedly 

for drill pads in the Barrow gas fields, by moving it 

from one drill pad to the next. 

Sand dunes are common in an area of the North 

Slope between the Meade and Colville Rivers. 

Although most of these dunes are no longer active 

and have been stabilized by a cover of vegetation, 

their shapes reflect the present wind direction, and 

they are thought to be of relatively recent age. 

C44 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

USGS scientist mapping in the Kelly River area, Brooks Range. 

Photograph by J eep J ohnson. 

Quaternary surficial deposits and their distribution across the N P RA ... 

(modified from Williams and others, 1977). ,.. 
72' 

70' 

68' 

0 5 10 15 20 MILES 

L_j___J___j_J 

0 5 10 15 20 KILOMETERS 

LLLLJ 

152' 148' 

SURFICIAL DEPOSITS 

EXPLANATION : Deposits not subdivided by age nor arrenged in colu mnar fashion by relative age. 

Unconsolidated deposits are Quaternary {possibly late Tertiary7l age as show n 

by letter 0 : Bed r~k is probably of Cretaceous age and older. 

- Marine silt 

-Marine sand 

- Upland silt 

- Eolian sand 

- Silt and muck 

I Qog t Outwash gravel and terrace 

deposit s 

[:§] High- level gravel (ancestral Colville I 

- Younger glac·ial till 

Older glacial till 

IT] Undifferentiated bedrock 

____ Contact between units, dashed 

where contact line is not certain 

..J..J....~.... Wave-cut eMf , substantially 

ified by Solifluction wocessed ha~ 

chures downslope. May 

with contact 

Modified from USGS l'!ellmlrery Suf1ialj [)epos~1s . Map ot K!ltl(lfllj l'ttrole\lm ReseM!-Aiaska 19 77. 

bv Jol'wl R W~Ums. Warren F. Yeend. L David Caner, a,.! Thomas D Ham 1on 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C45 
Although several episodes of widespread glacial 

activity occurred during the Quaternary, most 

authorities agree that the area north of the Brooks 

Range has not been glaciated. Localized alpine 

glaciers were present in the Brooks Range, and 

material eroded from the mountains by glacial processes was transported northward to the lower 

parts of the NPRA, where it was redistributed and 

deposited by streams and wind. 

The extreme climate that has existed in northern 

Alaska throughout most of the Quaternary has 

resulted in intense frost action in the fine-grained 

sediment and the formation of perennially frozen 

ground (permafrost} The relatively young frozen 

sediment has preserved a rich and varied fossil 

record of plants and animals. Most of the fossils are 

found in deposits of Wisconsinan age ( 70,000 to 

10,000 years ago} The most common vertebrate 

fossils are of mammoth, bison, horse, and mastodon. They are most abundant in river drainages 

and on valley floors, where the surficial deposits are 

thickest. 

The Quaternary rocks also contain a record of 

human presence in northern Alaska. Although it is 

widely believed that the first humans came to North 

America by way of Alaska, no solid proof exists. 

Archeologic sites in Alaska have been radiocarbondated at about 8,000 or 8 ,500 years old. Ages of 

12,000 to 15,000 years have also been suggested 

because the artifacts are similar to those found at 

older sites in Asia. Estimated deposition rates of 

stratigraphic layers between dated material and 

undated material some distance below corroborate 

the older ages. 

Archeologists study prehistoric remains in their search to understand 

the culture of the humans who migrated into northern Alaska. This 

NPRA archeologic site has been dated at 8,000 to 8,500 years old. 

These excavations were part of a larger archeologic study in the 

N PRA. Photograph lry J eep J ohnson. 

Quaternary river sand and gravel are commonly exposed lry relatively 

recent erosion. Photograph lry J ohn Schindler. 

C46 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
Kiana borrow pit. Gravel, the material required for the construction 

of roads, drill pads, and airstrips, is very scarce in the NPRA. 

Photograph by Irvin Tailleur. 

Quaternary life on the North Slope once included bison, mammoth, 

horse, mastodon, lynx, and many other animals and plants now 

extinct, or gone from the North Slope. It has been suggested that the 

increasing numbers of early humans living here after the last major 

ice age led to the demise of many of these species. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C47 
Permafrost 

Because the NPRA lies north of the Arctic Circle, 

the extreme Arctic climate causes the formation of 

permafrost. Permafrost is present wherever ground 

temperature remains continuously below 0°C for 

years. It can cover an entire region, such as the 

North Slope, or be discontinuous, as in southern 

Alaska. Nearly all of the NPRA is underlain by permafrost, above which is the "active layer"-all the 

material that thaws in the summer and refreezes in 

the winter. The thickness of this active layer varies 

with local conditions but in the NPRA ranges from 

2 to 4 feet. The active layer forms a boggy, swampy 

surface during the summer thaw. The extreme 

Arctic climate of northern Alaska dates back to the 

pre-Quaternary ( 3 million to 2. 5 million years ago), 

and so permafrost has been present for a long 

period. 

There is little or no mineral cement or binding in 

the fine-grained surficial sediment. The individual 

grains may be surrounded by ice, resulting in icerich permafrost. Permafrost is said to be ice rich 

when it contains more water in the form of ice than 

the ground could possibly hold if the water were 

liquid. In general, the Arctic Coastal Plain is underlain by ice-rich permafrost. If the ice melts, settling 

problems can be extreme and thus present a great 

engineering challenge. 

Permafrost is the dominant factor that influences 

Hill 

C48 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

the design, engineering, construction, and transportation phases of any operation in the Arctic. 

Because ice is impermeable, there is no vertical 

drainage below the thin active layer. The base of the 

active layer is an irregular surface that ponds water 

during the thaw, and so in areas of steeper slopes, 

the water-saturated sediment is ready to start sliding downhill at the least disturbance, and mudslides 

are common. During the warm months, the wet, 

soggy tundra is difficult to walk on and impassable 

for most ground vehicles. In the past, heavy tractors 

with "caterpillar" belt treads have been used in the 

summer, sometimes with the bulldozing blade 

down to remove soft tundra. Some tractor scars are 

still visible and still eroding after 40 years, and so 

All of the NPRA is underlain by a nearly continuous zone ofpermafrost. This diagram shows the ef!ect of surface f eatures on the 

distribution of permafrost. Only the area beneath Lake Teshekpuk, the 

largest lake in the NPRA, lacks a permafrost zone (adapted from 

Ferrians and others, 1969). 
alternative means have been developed for summer 

ground transport. Large ground vehicles now use 

wide balloon tires that increase the area of the 

"footprint" and thus decrease the pressure exerted 

on the tundra. 

Most activity in the NPRA involving heavy equipment takes place after the tundra has frozen and is 

protected by a snow cover. The surface can then be 

used for transportation, and little or no damage is 

caused. Ice roads can be built for the use of surface 

vehicles. Large or permanent structures are placed 

Tracks made by a tracked vehicle in the tundra during the Pet--4 

program. 

on pilings well above the tundra surface, so that 

they do not form a "thaw bulb" in the upper surface 

of the permafrost and create engineering problems 

or unsightly reminders of human activities. 

However, drill pads and roads must be carefully 

located, so that natural drainage is disturbed as little 

as possible, or else erosion will occur. Aircraft runways are located on frozen lakes wherever feasible. 

Permafrost affects all facets of Arctic operations, 

but, as demonstrated by this program, the problems 

can be solved. 

Colder temperature 

-

Layer of annual 

temperature 

fluctuation 

Freezing point 

oo 

+ Warmer temperature 

-

Generalizrdgraph of ground tnnperal11 1"1' 11f'nllsdtpth. In tht Arrtir, 

annual temperalurf l'arialiow may be ddntl'!l to a drpth o(70 to I()() 

f eel. The Iowa bounda ry f or prnnruzmJl,, ji"ozrn gm111 11 / is a!JOu t 

1,000 fret at Barrow and 2,000 fret at f'nulh or Ua 1· (modijirdji11m 

Haugen and Brown, 1971). 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C49 
Permafrost contributes to the development of 

certain ground phenomena that are immediately 

apparent even to the most casual observer-such 

as polygonally patterned ground and oriented 

lakes. Patterned ground is the surface manifestation 

of vertical ice wedges. The ice wedges are thought 

to form in contraction cracks in the tundra that fill 

with water during the summer thaw and refreeze 

and expand during the next winter. Thus, over time, 

"Resurfacing'' an ice road at South Simpson . Using ice roads for 

transporting heavy equipment during the winter months prevented 

lasting damage to the tundra. Photograph by j ohn Schindler. 

the vertical ice body is enlarged until a condition of 

relative equilibrium is reached. The cracks intersect in irregular patterns, but the most common are 

five-sided polygons. 

Oriented lakes, strikingly evident on maps of the 

coastal plain, are believed to result from the interaction of prevailing northeasterly winds and ice. 

The long axes of these lakes are at right angles to the 

prevailing wind direction. During the spring thaw, 

Polygonal or patterned ground results from ground contraction during extremely low winter temperatures. Water and snow that collect in 

the contraction cracks eventually turn to ice and create intersecting ice 

wedges that surround each polygon. Photograph by J eep j ohnson. 

CSO THE NATIONAL PETROLEUM RESERVE IN ALASKA 

the lake ice melts along the shore first, leaving a 

moat of water surrounding an ice island. As the 

wind velocity fluctuates, this ice island moves back 

and forth in response to the windforce and wind 

direction. The water is forced around the ends of 

the ice and erodes the ends of the lake, and thus 

elongates the lake basin at right angles to the direction of the prevailing wind. 
Rounded hills with ice cores, called pingos, commonly form in the 

centers of drained lakes as the water -saturated soil freezes inward 

from the basin sides. When the center finally freezes, the ice can only 

expand upward and forms a low hill. Photograph by George Gryc. 

Oriented lakes result from interaction of the prevailing northeasterly 

winds with the lake ice. Photograph by George Gryc. 

Sampling a small ice wedge beneath the tundra cover. Photograph by 

Jeep Johnson. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C51 
Environmental stipulations 

and monitoring 

The Naval Petroleum Reserve Production Act of 

1976 (Public Law 94-2 58) made specific reference 

to protecting the environment. Recognizing that 

the NPRA is underlain by permafrost and thus is 

most sensitive to any actions that alter the surface, 

the USGS and the BLM met together and drafted an 

MOU that defined the responsibilities of each 

agency. 

Because knowledge about the characteristics of 

permafrost is not widespread, it was decided that 

the USGS would draft a set of stipulations governing 

surface activities and movements which would be 

rigidly followed during the exploration program. 

Monitors representing both the USGS and the BLM 

were to continuously observe all activities. Under 

the provisions of the MOU, the USGS prepared each 

year an Annual Plan of Operations that specified the 

locations of all wells proposed for the year, their 

estimated total depth, construction designs, timetables for all operations, and, possibly most important, the exact routes to be used by the 

construction crews. 

When the annual plan was completed, site-specific environmental assessments and engineering 

surveys took place concurrently. Thus, the construction and drilling designs incorporated specific 

environmental considerations tailored to the conditions at each site. Environmental surveys were 

conducted during the summer and included 

gathering soil and surface information, as well as 

locating water sources and borrow sites. The areas 

were also checked for potential conflicts about 

archeologic, fishery, and wildlife problems. For 

example, borrow sites were relocated if a suspected 

archeologic site was involved, or the site was thoroughly examined and recorded by archeologists 

before being disturbed. Furthermore, the operational schedules were adjusted to cause minimal 

effect on wildlife-sensitive areas, such as waterfowl 

habitats, caribou-calving grounds, and falcon-nesting places. Such environmental factors were considered at every site. 

ENVIRONMENTAL STIPULATIONS 

1. Heavy equipment may be transported on winter roads only after the tundra is 

seasonally irozen to a 12-inch depth, and must cease when daytime spring melt 

of snow begins. 

2. No bulldozing of tundra areas for roads or trails. 

3. Camps may be located on solidly frozen ponds or lakes, provided that no toxic 

or hazardous materials are allowed to be dumped onto the ice. 

4. Exploration activities will employ low-ground-pressure vehicles. 

5. No historic site, archeologic site, or camp, either active or abandoned, shall be 

disturbed in any manner. 

Some of the basic environmental stipulations governing surface 

activities in the NPRA, taken from the MOU. 

Colville Delta 

• Important fish spawnrng habrtat 

• H1gh concentration of foxes. polar bear, ground 

squrrrels and bird l1fe 

Colville River, bluffs and high shrub zone 

• Crrtrcal nesting srtes for peregrine falcon and other 

brrds of prey 

• Hrgh concentratron of moose 

• F1sh resources greatest of all North Slope 

Icy Cape 

• Hrgh densrty of water fowl 

• Important to mrgrat1ng shorebrrds 

Point Barrow 

• Area exhibits a number of physrcal and biological 

extremes of interest to researchers 

• Protectron of representative research sites 

Teshekpuk 

• High concentratron of molting geese 

• Carrbou summenng, wrntering, and calv1ng area 

• Waterfowl and shorebird feeding area 

Utukok Uplands 

• MaJor canbou calvmg area 

• Supports large numbers of grrzzly bear and wolverrne 

Unique ecologic areas in the NPRA (modified from National IIIIo.. 

Petroleum Reserve in Alaska Task Force, 1978). ,. 

C52 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
160' 

71' 

70' 

68' 

158' 

' "'-' 0 5 10 15 20 MlES L..J._j_j_J 

0 5 10 15 20 KlOMETERS 

L...L.LLl 

151' 

I 

_) 

D 

Areas tentatively identified: 

Colville Delta 

Colville River 

Icy Cape 

Point Barrow 

Teshekpuk 

Utukok Uplands 

148' 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C53 
The 1977-82 exploration program was designed 

so that most action took place during the winter 

months, to minimize environmental disruptions. 

Because tundra, when frozen and protected with 

snow cover, makes a good working surface, seismic 

operations and road and trail construction were 

largely restricted to the winter season and were 

rigidly controlled. 

A few environmental problems arose, but 

promptly corrected, at the 28 exploratory wells 

drilled during the 1977-82 program: minor fuel 

leaks and spills at the drillsites and from the mobile 

trains, a few instances of improper waste-water 

treatment, and insufficient protection for the 

tundra during the burning off of small amounts of 

waste oil. Only two problems were significant: one 

was the difficulty of reestablishing the vegetative 

cover in the coastal marine environment, and the 

other the seepage of fluids through the berm surrounding the reservoir pit at the Inigok site. This 

seepage resulted in some damage to the tundra 

vegetation, but it is recovering. It was found that 

planting tundra bluegrass, with plenty of fertilizer 

added, speeded the recovery. 

The environmental impact of the program was 

minimal to both the land surface and the wildlife. 

Only about 250 acres was affected by drill pads and 

reserve pits, and another 168 acres by borrow sites. 

In addition, about 105 acres was covered over with 

permanent runways, 15 acres was used as burial 

sites for old debris, and about 3 acres was occupied 

by all-season roads. The total acreage disturbed was 

about 540 acres-only 0 .00227 percent of the 

23,680,000 acres of the NPRA. About 95 percent of 

this 540 acres will be difficult to identify within 3 to 

5 years. Only the permanent runways and roads will 

remain in 20 to 25 years as a result of the 1974-82 

exploration activities in the NPRA. 

Grazing caribou near the Lisburne wellsite. Photograph by J eep 

johnson. 

C54 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
Cushion pink (Silene acoulis) with its long, strong mots anchors 

itself finnly on rocky mountain summits. 

Botanist collects samples of willow growing along a riverbank as part 

of ecologic-profile studies. Photograph by J eep J ohnson. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C55 
Trafficability and movement 

of supplies and materials 

In the NPRA and elsewhere on the North Slope 

where no permanent roads exist, winter is the best 

time for overland movement. During the earlier 

petroleum-exploration program of 1944-53, caterpillar-type tractors were the principle pieces of 

equipment used to transport large items. Today, 

they are supplemented by rolligons and other vehicles with rubber tires. Aircraft were used occasionally during the earlier U.S. Navy exploration but 

became the principle means of transportation during the exploration program described here. 

Land traffic was carefully restricted. Overland 

travel was allowed only after the ground was frozen 

and snow covered, and before the beginning of the 

spring thaw. Bulldozing was allowed to level snowdrifts, but the dozer blade was always kept above 

the tundra surface. Vehicles were selected for their 

low-ground-pressure qualities. The tundra was further protected by using only selected trails, and 

repeat runs were required to offset previous tracks, 

to avoid rutting. Frozen lake surfaces were used as 

much as possible, and banks were crossed at low 

angles to minimize damage. The challenge was to 

transport thousands of tons of machinery, drilling 

mud, pipe, fuel, and other supplies to remote drillsites; to construct all the needed facilities; to drill a 

wildcat well; and then to move off the site, leaving a 

minimum imprint on the area. 

Aerial view of Lonely, the "hub" of the exploration effort. Photograph 

by J ohn Schiruiler. 

C56 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
lncineratoT used for burning sludge and solid wastes at Camp Lonely. 

Photograph by j eep johnson. 

Some nonburnable wastes that were not removed by barge were bw·ied 

in landfill sites similar to this one. Photograph by j ohn Schindler. 

Logistics 

The logistic problems attached to an exploration 

program of this size in the harsh, remote area of the 

NPRA were great and were complicated by the 

pervasive presence of permafrost on the environmentally sensitive Arctic Coastal Plain. An idea of 

the size of the task is illustrated by the volume of 

material that was moved each year. Every year that 

the USGS was in charge of the active exploration 

program ( 1977 through 1982 ), more than 50,000 

tons of fuel, equipment, and supplies was transported to Camp Lonely, the "hub" of the exploration effort. 

The distant-early-warning (DEW)-Iine site at Pitt 

Point, known as "Lonely," was chosen as the location for the central camp by the U.S. Navy before 

transfer of the exploration effort to the USGS. This 

location was picked because it had a 5,000-foot allseason gravel runway, some fuel tanks already in 

place, a good beach for unloading barges, and a 

large unoccupied gravel pad, and it was centrally 

located for the Navy's exploration plan. 

Lonely was a large camp. It was home for about 

100 men and women during the busy winter drilling seasons. They lived comfortably, with heat, 

light, and powe r supplied by generators. They had 

hot meals, warm beds, hot showers, flush toilets, 

and good recreation and exercise facilities. Camp 

Lonely was equipped with water- and sewage-treatment plants, and an incinerator for burning sludge 

and solid wastes. The camp was operated with the 

supervision and approval of the State. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C5 7 
The drilling camps were smaller versions of 

Camp Lonely. Locating a water source was the first 

job of the drillsite-construction crews. Then, smallscale waste-treatment systems were set up. Burn 

baskets were used to burn wood and paper products. Metals and nonburnables were hauled from 

the drillsite to Camp Lonely or to one of several 

approved burial sites in the NPRA. Drilling muds 

was contained in reserve pits. 

Construction and seismic camps were mobile 

facilities, and their utilities differed slightly. Drinking water came from melting snow when lakes were 

unavailable. Wastes were either incinerated or 

hauled to Camp Lonely or a drillsite. The State 

permitted these small mobile camps to dispose of 

small volumes of oil and other burnables by open 

burning. 

Welder at Camp Lonely. Photograph by J eep j ohnson. 

Camp Lonely was also needed to stockpile drilling supplies. Almost all the wells drilled were far 

from any previous drilling, and little was known 

about the subsurface conditions. Detailed drilling 

plans were made before drilling each well-plans 

based on the best geologic knowledge obtainable. 

However, subsurface conditions seldom were precisely as predicted, and the amounts of casing, 

cement, mud, bits, fuel, and myriad other necessities were either overestimated or underestimated, 

thus, a local stockpiling area was required. Unpredictable drilling conditions, such as overpressured 

zones and lost-circulation zones, could require 

extra amounts of drilling mud and additives, or even 

an unplanned string of casing. This unpredictability 

of wildcat exploration requires a nearby source of 

all kinds of drilling supplies. 

Landing barges on the coast near Camp Lonely. Shipping by barge is 

the most inexpensive method of transporting large amounts of material to the Arctic coast but is generally restricted to a short period in 

August when the ice retreats from the shorelines. Photograph by S. 

Krogstad. 

C58 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

Most of the annual 50,000 tons of cargo went to 

Camp Lonely, where it was inventoried and 

assigned to a well; then, it had to be transported to 

the well location and, if surplus, transported back to 

Camp Lonely and put into the inventory again. 

During the exploration program, more than 

250,000 tons of materials was transported by aircraft alone! 

The bulk of the material transported from the 

"Lower 48" to the NPRA came by barge once a year. 

The ice generally opens and retreats from the 

beaches long enough in early August to allow 

barges to land and unload along the Alaska shore of 

the Arctic Ocean. If barges can get in, they are by far 

the cheapest method of shipping bulk cargo. 

Some rigs drilled as many as three wells during 

the drilling season-a situation that required close 
CA TCO Rolligon. Huge balloonlike tires exert only 4 to 5 pounds per 

square inch when carrying as much as 80,000 pounds across the 

frozen tundra. Photograph by J eep J ohnson. 

scheduling and precise planning. Rigs were not 

moved during the summer, when the tundra was 

soft. Most rigs were moved with a combination of 

large C-130 Hercules aircraft with all-terrain vehicle (A1V) support. The primary vehicles used were 

CATCO Rolligons-a very large tractor-trailer combination mounted on huge, low-pressure, balloonlike tires. These vehicles could carry an 

80,000-pound load while exerting only 4 to 5 

pounds per square inch on the frozen tundra-less 

than the average human foot pressure. Each well 

drilled required that the drill rig, along with the 

proper amounts of casing, cement, mud, fuel, bits, 

and so on, be moved to the location. It has been 

estimated that about 10,000 tons was transported 

to the average location and that the typical rig move 

was about 50 miles. These figures translate into 

approximately half a million ton-miles per location. 

This huge logistic task was coordinated through 

Camp Lonely, where the all-season airstrip was 

expanded, full communication networks were 

installed, and a large-capacity fuel-storage facility 

was constructed. 

Airstrips 

Both ice and gravel airstrips were used in the 

1977-82 NPRA program. The advantage of airstrips 

and roads made of ice is that they are not permanent 

and thus more acceptable environmentally, and are 

less expensive. Lakes can also be used to an advantage for airstrips for aircraft up to C-130 Hercules 

and Boeing 73 7 size. For lake or sea-ice airstrips, 

snow is cleared from the ice surfac e and then 

grooved to increase traction. Lake ice must be 4 

feet thick for full-load operations ( 4 1/z feet for 

brackish water) In contrast, airstrips on tundra 

require 1 foot of ice above the frozen ground. 

Hercules C-130's (Heres) provided contractors with the high-volurne, high-tonnage capability necessary to transpm·t drilling and 

construction equipment to the reserve. Photograph by Edmund 

Grant. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C59 
The construction and drilling season normally 

was limited to the time between winter freeze and 

spring thaw. Overland travel was not allowed until 

the surface was frozen to a depth of 12 inches and 

the average snow cover was 6 inches thick. These 

regulations restricted the winter working season to 

about 170 days. Most ontundra ice airstrips could 

be operational more quickly than lake strips; the 

time saved might allow a well to be completed in 

one season instead of two. The necessary requirements for building such an airstrip are a water 

source nearby and a large flat open area, as much as 

6,000 feet long, on which not less than 12 inches of 

water can be layered and frozen . Vehicles carrying 

insulated water containers are used to spread the 

water in thin sheets. The water is spread at a rate 

that allows complete saturation ofthe surficial snow 

and tundra before freezing. Pumping systems using 

insulated pipes were used to flood some airstrips to 

hasten thickening of the ice. Using either method, 

the average ontundra ice airstrip required 7.4 million gallons of water (excluding any required maintenance of the strip) and was built in a few days. An 

airstrip of this type causes little damage to the 

tundra but has only a one-season lifespan. 

f--- ----150 ft. runway ------j~ 

Runway lights _' ''.. Tundra surface 

Winter aintrips were constructed on lakes, sea ia, and tundra. Lake 

ice rnust be 48 inches thick, and bracki1h ice 54 inches thirk . In 

addition, to prevent tundra damage, a rninirnum of 12 inches of ice 

was required on top of the frozen tundra (modified [1-om Mitchell, 

1983). 

C60 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
Workers test the thickness of lake ice. Photograph by J eep j ohnson. 

Unloading drill pipe from a Hercules at the Camp Lonely airport. 

Photograph by J eep j ohnson. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C6l 
Ice roads 

Ice roads were used at most locations for routes 

between the drillsites and airstrips, borrow pits, 

and water sources. Snow is compacted over the 

frozen ground and repeatedly flooded with water to 

build up ice layers. Roads carrying heavy traffic and 

heavy loads required thicker ice and more maintenance than those made for less traffic and lighter 

loads. A 3 7 -mile-long road, the longest in the NPRA, 

from the Kikiakrorak River delta to the Inigok allseason airstrip, was used to transport 90,000 cubic 

yards (about 6,000 truckloads) of gravel to build 

the Inigok drill pad and airstrip. The route took 

advantage of every lake, pond, and river along the 

way. A total of 3 5 million gallons of water was 

required to form the ice road. 

At the Inigok and a few other drillsites, it was 

essential that the airstrips remain operational 

throughout the summer, so that the drilling could 

continue without interruption. The Inigok well 

needed an estimated 3 30 drilling days to reach a 

total depth of20,000 feet. If drilling had taken place 

only during the winters, three seasons would have 

been required-involving twice breaking camp, 

three times setting up camp, costly idle time for the 

drill rig between winters, and added risk associated 

with reentering the drill hole each new drilling 

season. Despite the environmental and economic 

drawbacks to gravel-road construction, the lower 

price and lower risk associated with year-round 

drilling made it worth the cost. 

Aerial view of an ice road. Photograph by j eep Johnson. 

Crushed aggregate surfacing , 1 in . minus , 0.5 ft thick 

r- ProtE!cti•ve membrane , joints sealed with silicone sealant 

l-------+-+-+-------155tt.----------------11 

2 y, in. H.l. 60 polystyrene insulation (2 layers with staggered joints) 

C62 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

Runway lighting I 

Cross section of a typical all-season airstrip. Gravel airstrips were 

more expensive to construct but could be used year-round (from 

Mitchell, 1983 ). 
Gravel hauled along the ice road at South Simpson. Photograph by 

john Schindler. 

Large trailers used wide balloon tires f or transporting heavy equipment across the tundra. Photograph by J eep johnson. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C63 
71'03'44" N 

2MILES 

2 KILOMETERS 

1 ~ , \ I 

Example of a carefully planned, environmentally sensitive transportation route at the Walakpa No.2 lest well. Instead of a straight road 

connecting the well to the airstrip, the chosen route avoided the tundra 

surface as much as possible by taking advantage of every lake, pond, 

and river along the way. 

C64 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
Scouting the Lisburne wellsite. Drill-pad location is "staked out" in 

background. Photograph fry j eep Johnson. 

Two-season drillsite layout for the Awuna No. 1 test well (from 

Mitchell, 1983). 

Drillsite construction 

Design of drill pads evolved during the period 

when the USGS conducted the exploration program. While the U.S. Navy was in charge of the 

program and shortly after the USGS took over, a 

design was used that had been developed at the 

Prudhoe Bay oil field. The pad was constructed of 

thaw-stable gravel, not less than 5 feet thick. This 

design became known as the "thick pad" and was 

used by the USGS for only its first drilling season. 

Most of the wells drilled by the USGS to help 

evaluate the petroleum potential of the NPRA were 

to depths that could be reached in one winter 

season. The Naval Petroleum Reserves Production 

Act of 1976 (Public Law 94-258) specifically prohibited development and production of hydrocarbons, and an all-season work surface was not 

needed for exploration and testing. As mentioned 

above, gravel, plentiful in the Prudhoe Bay area, is 

extremely scarce in the NPRA. Therefore, a "thin 

pad" concept was developed. 

A few wells were too deep to complete in one 

winter season. For these wells, all-season pads and 

airstrips were designed that allowed year-round 

operation of the drill rig and provided the required 

facilities and support to keep the operation running 

throughout the summer thaw. All wells drilled on 

the NPRA during the more recent program used 

one or another of these three designs. 

One-season drill pads 

The design of the pad was selected after the well 

location, target depth, and type and size of drill rig 

had been agreed upon. The site was surveyed, and 

lakes were examined and sounded for water supplies, as well as for suitability of use as an ice 

airstrip. In addition, environmental studies were 

conducted, including fisheries and wildlife. The 

areas were also checked to ensure that no archcologie sites would be disturbed. The route of the 

construction train to the site was carefully chosen 

and marked, so that it could be followed easily even 

when visibility was severely reduced. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C65 
Drilling the Seabee No. 1 test well near Urniat on the Colville River. 

Photograph by john Haugh. 

C66 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
N 

1 

PLAN VIEW 

SECTION A-A' 

Reserve pit 

188ft. 

Plan view of a one-season, thin-pad design. For safety 1WLsom, the 

wellbore, the flare pit, the pad used for bulk fuel storage, and the 

drilling camp on one-season drill pads were separated by atleast300 

feet (modified frorn Mitchell, I 983 ). 

Cross section of the thin-pad design. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C67 
H the thick-pad design was selected, the drill rig 

was located adjacent to the reserve pit, and the fuelstorage and camp areas were set back from the rig 

for safety. The pad area around the rig was used for 

storing drill pipe, chemicals, and mud. The reserve 

pit was large enough to hold all the spent drilling 

fluids. A flare pit was used when well fluids 

recovered during testing needed to be burned off 

The pad was elevated about 5 feet above the ground 

surface and consisted of sufficient fill to prevent the 

summer thaw from reaching the original tundra. 

Thus, the subsurface beneath the drilling operation 

remained frozen. 

As the exploration program continued, the thickpad design was modified to suit the conditions in 

the NPRA. Because most of the drilling was planned 

for the winter season, this design was modified to a 

two-layer pad to conserve the scarce gravel. The 

lower layer contained ice-rich material excavated 

from the reserve pit, and the upper layer was of 

relatively thaw stable material from a borrow site. 

Settling of the pad was expected when the ice-rich 

lower layer thawed. Such thawing was caused both 

by heat resulting from the drilling operation and by 

the summer melt. The drilling operation generates 

heat, and warm fluids are circulated in the hole, so 

that thawing occurs beneath the drill rig even in 

winter. 

To avoid settling of the drill structure, NPRA rigs 

were supported by pilings extending into the 

ground well below the expected thaw level. From 

50 to 210 pilings were required, depending on the 

size of the rig. These pilings were set between 14 

and 25 feet below the surface, the deeper pilings 

were placed under the subbase and derrick areas. 

To set the pile, a 2-foot-diameter hole was augered, 

the pile put in place, and the hole filled with a slurry 

of water and soil that froze the piling in place. Thus, 

the drill rig was supported by pilings and not by the 

pad. 

C68 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

.t' 

~ 

"' 

Original 

ground 

.--+------500 ft.-------1 

A ~ Reserve pit Camp area ... 

[ 

4:' 

N 

., 

203ft. 362ft. 220ft. 

PLAN VIEW 

Reserve pit material 

SECTION A-A' 

Plan view and cross section of a year -round or all-season drill pad. 

These pads were modified from the old design by adding a layer of 

synthetic insulation between the lower, ice-rich layer and the thawstable gravel surface (from Mitchell, /983 ). 

J 0 

0 

... 

J 

.t' 

0 

~ 
- Borrow gravel 

- Original ground 

- Ice rich material from reserve pit 

- Insulation pad 

Protective membrane 

Dike 

/ /. 

Y:z in. insulation 

/ 

( 

/ 

/ 

Borrow 

4000 FEET 

2 Y2 in. insulation 

50 

VERTICAL SCALE EXAGGERATED 1.5:1 

100 FEET 

---- --

Cross section of the Lisburne drill pad, an all-season thick pad 

(from Mitchell, 1983). 

Layout of the Lisburne drillsite (from Hewitt, 1983). 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C69 
Soil conditions varied considerably in the NPRA, 

but, in general, they were unfavorable for drill-pad 

construction. Most drill pads were located on icerich mud or silt. These materials were excavated 

from the reserve pit and used as the lower layer of 

the pad. The upper layer was constructed of fine 

sand that was found in dune areas or in banks along 

the rivers or lakes. 

The normal time to construct a thick drill pad 

was about 30 days. Construction usually started in 

November or December, to allow enough time for 

the drill rig to be moved to the location, the well to 

be drilled, and the rig removed before the thaw in 

mid-May. The drilling camp, fuel, and equipment 

were usually stacked on timbers and left until the 

following winter's ice road and ice airstrip were 

again usable. 

The thick-pad design was abandoned after the 

1977-78 season because of experience gained at the 

South Meade site. This test well was located in a 

Construction of one-season thick pad at the Seabee wellsite. Photograph by j eep j ohnson. 

swampy area, and the original design called for a 

borrow site about half a mile away. To save costs and 

with the geologist's approval, the drillsite was 

moved to the borrow site. The reserve-pit excavation produced sufficient material for a thin ice-rich 

pad, assuming a one-winter operation. This procedure eliminated hauling from a borrow site and 

building an ice road between the pad and borrow 

site, and thus reduced costs. It also reduced the 

environmental impact. The experiment was a success, and the South Meade site was used for a second season with only minor repairs. 

The thin-pad design provided a pad thickness of 

about 2 feet and allowed the pilings to be cut off 

above the original surface. The elevated pad also 

kept the drill rig relatively free of snow. The 12 thin 

pads constructed were totally satisfactory. 

The thin-pad concept had several advantages. 

The pads were less costly to construct than the 

thick or all-season pads. The need for borrow material, its removal, and hauling was not required. 

Fewer men, less time, and less equipment were 

needed to complete the preparation of a drillsite. 

Construction and maintenance of an ice road 

between the site and borrow pit were also unnecessary. Furthermore, shortened construction time 

meant that more days were available to drill the 

well. 

The thin pads were also environmentally preferable. Thin pads reduced the area of disturbance by 

eliminating a borrow site and made rehabilitation 

and revegetation easier. Use of the thin-pad design 

eliminated the need to break up and spread the fill, 

because it was not thaw stable. During the summer 

after the drilling, the thickness of the pad was 

reduced about 50 percent or more by ice melt and 

settling. In addition, the fine-grained soils used in 

the thin pads were more suitable for revegetation 

than the gravel surfaces of the thick pads. 

The Lisburne No. 1 test well was completed in summer 1979. Photograph by J eep j ohnson. 

C70 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
Year-round drill pads 

The exploration program called for a few 20,000-

foot-deep wells, requiring an estimated 350 days of 

drilling, testing, and plugging. This work would 

have required three winter-drilling st;asons, two 

pad reconstructions, and about 500 standby days 

when the drill rig was idle. A total of 900 days was 

estimated to be required. In contrast, an all-season 

program could be completed in only 520 days. 

Another advantage of all-season drilling is the 

reduced risk. Risk is always associated with suspending and reentering a well. In permafrost areas, 

casing can collapse in inactive wells because of 

ground settling or freezing in the permafrost zone 

that blocks reentry. 

Six-inch-thick insulation protects the .permafrost layer beneath the 

Lisburne drill pad. Photograph by J eep j ohnson. 

To prevent heat from penetrating the permafrost 

below an all-season drill pad, a very thick fill or an 

insulating layer within the pad was required. The 

NPRA all-season pads used Styrofoam for this 

insulation because gravel cost more, added to the 

environmental disturbance, and was scarce. The 

Inigok well is a good example of an all-season pad. 

The drill rig was supported by 218 timber piles 

slurried in place at depths of 25 to 4 5 feet, depending on the distance from the well. The piles closest 

to the wellbore needed to be set the deepest to 

withstand the most force from drilling and the heat 

generated by the drilling process. 

Several other measures were taken to ensure that 

the drill rig would be adequate for a year-round 

period. Heavy steel beams spanned the deep-set 

center pilings, and 12- by 12-inch timber beams 

over the outlying pilings were used to distribute the 

load. A 6-inch-thick layer of insulation was applied 

to the outside of the conductor pipe to prevent heat 

flow from the well. Other heat sources were contained by a 6-inch-thick layer of Styrofoam under 

the drill rig, which was placed at an angle and 

covered with a plastic liner to direct the flow of 

liquids into the reserve pit. The upper layer of fill 

was gravel from a borrow site. 

The NPRA exploration pad designs proved to be 

entirely satisfactory. The thin-pad design was the 

best choice for wells that could be completed 

within one winter season, and the all-season design 

was satisfactory for wells requiring several seasons 

to complete. 

A gravel access road leads f rom the wellsite to the bon-ow site and allseason Here airstrip. Photograph by j eep J ohnson. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C71 
How were cleanup 

and rehabilitation 

accomplished? 

Human concern with the deteriorating environment has reached even to the remote areas of 

Alaska. Pre-1960 construction and engineering 

activities in Arctic Alaska including the Pet-4 program of 1943-53, the construction of DEW-line 

stations, and other military and industrial activities, 

were all conducted without much consideration 

for possible environmental impacts. The main concern was getting the job done. Although the 

amount of debris and the extent of damage to the 

North Slope environment were small and localized, 

they were starkly visible on the fiat and otherwise 

featureless Arctic plain. Sites along the coast, 

including Barrow, had large accumulations of abandoned or surplus materials. 

Fish Creek drillsite,from the 1949 season, as it appeared in 1977 

before cleanup. Photograph by John Schindler. 

C72 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

Responding to growing criticism, the U.S. Navy, 

as NPR-4 managers, began a cleanup program in 

1971 that was continued by the USGS. The cleanup 

of old sites and the rehabilitation and revegetation 

of new drillsites were combined into one large 

program. 

The litter consisted mostly of empty 55-gallon 

fuel drums. During the Pet-4 program and the 

ensuing operations, fuel of all kinds was supplied in 

drums that were abandoned once the contents had 

been used. Metal deteriorates very slowly in the 

Arctic. Tens of thousands of these drums were scattered throughout the Reserve, especially in coastal 

areas, at drillsites, construction sites, and along the 

trails followed by old tractor trains and geophysical 
and geologic survey crews. In 1976, the Navy 

picked up 9,019 barrels, and this was only a beginning. 

In 1977, under USGS management, cleanup of 

old sites was continued, together with rehabilitation and revegetation of the latest drillsites. A barrel 

crusher was obtained to reduce the bulk, and in 

1977, 16,743 barrels were crushed, and 485 tons of 

debris collected, burned, or stockpiled. In 1978, 

1,235 tons of debris was burned or stockpiled. In 

1979, the summer cleanup crews worked out of 

tent camps near the sites, thus cutting the cost of 

daily commuting from a base camp. During that 

summer, more than 10,000 tons of debris was handled, burned, or stockpiled for later disposal. 

The U.S. Navy hauled much of the debris at Barrow to Seattle for final disposal-a difficult and 

expensive process--because it was thought that 

burial in permafrost ground would be difficult and 

Part of the cleanup operation at old drillsites consisted of cutting off 

pilings "below grade" of the drill pad. Photograph by J ohn Schindler. 

environmentally unacceptable. However, hauling 

to the "South 48" was very expensive and simply 

moved the problem to another region. Thus, in 

1980, burial at carefully selected sites was begun. 

The burial plan included stripping away the organic 

overburden and stockpiling it to one side, then 

excavating a pit of sufficient size to hold the debris, 

placing the debris in the pit, compacting it, and 

carefully backfilling with the original material so as 

to cover it at least 2 feet deep. Because the overburden was generally exposed to the winds and 

cold for less than 2 days and then protected by 

blown snow after replacement, many plants survived. This meant that the area recovered far more 

quickly than an area seeded with grass. 

The first step at rehabilitation of a drillsite was 

routine cleanup. All the debris was picked up and 

burned or returned to a disposal site when the 

drilling was completed. Pilings were cut off below 

ground surface, if possible, and pile caps and sills 

were burned. Final cleanup took place after the 

ground had thawed. 

After the cleanup stage, the work required 

depended on the drill-pad design. For thick pads, 

the pad elevation was lowered, and the excess pad 

material dumped into the reserve pit. Thinner pads 

required no rehabilitation, and the five insulated 

pads required only precautionary rehabilitation. It 

was important that the Styrofoam remained buried 

because otherwise it could become a source of 

litter. 

After cleanup, the site was ready for seeding. 

Active seeding was done before the end of June; 

dormant seeding was done after the first freezing 

temperatures of the fall. About 50 pounds per acre 

of seed mixture was sowed, and 600 pounds per 

acre of nitrogen-phosphorus-potassium fertilizer 

was applied. Seed was worked in with tractor tracks 

Barrel crusher. Photograph by John Schindler. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C73 
liurn ing dt hris at lht' Oumalik r!t'OIIII/J site. PlwlografJh b_y John 

Srhiudler. 

Sn/111' i11 romh11.1tihlt materia/ 1m ., di.,Jm.,nl o/ in lallllfdl.' aJ!Jmll'i'd hv 

t/11' Stall• of ;\/aslw. 1'/wtogmJih h\•.fohn Srhi1111/er. 

A I"I'Ffgttation Rototillrr prrparrs thr soil atthr Wa/akpa No. /test 

wdl. l'h otograJih bv.John Srhindlrr. 

C74 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

Helicopters were used during the cleanup program for transporting 

debris to the burial site at Grandstand. Photograph by j ohn 

Schindler. 
Before and after vzews of the Oumalik wellsite. View on the right was 

taken less than a year after the cleanup. Photographs by j ohn 

Schindler. 

to ensure soiVseed contact and prevent wind erosion. This method proved to be moderately successful in the inland locations but failed along the 

coast. After considerable experimentation, it was 

determined that tundra bluegrass was best for the 

coastal locations. This bluegrass is native to the 

North Slope and allows for other native mosses, 

lichens, and grasses to reappear. The fertilizer was 

spread by a helicopter with a special hopper, then 

worked in to a depth of 4 inches below the surface 

with a cultivator. 

Damage by traffic over winter trails was slight and 

mostly was confined to the heavily traveled trails 

near Camp Lonely and Barrow. A "cropduster" airplane was used to distribute fertilizer in these disturbed areas. Both the ontundra ice roads and the 

runways disappeared with the thawing of the active 

layer in spring, but in some places the tundra would 

turn brown or dark green. The brown color was 

caused by freeze-burn of the vegetation through the 

ice, which did not insulate as well as the snow cover. 

The green color resulted from a depression in the 

surface caused by excess weight, creating wetter 

conditions and more plant growth. Only a small 

percentage of the 15,000 line-miles of seismic work 

became green or brown trails. In any case, these 

colors were short lived and disappeared within 5 

years. 

Borrow sites were judiciously chosen and carefully mined, and thus required little rehabilitation. 

Most borrows were in areas flooded by the spring 

runotl; and so after a year the sites were indistinguishable from the surrounding areas. In selecting a borrow site, a source was chosen where 

mining would have no effects that could not be 

corrected by natural processes within a couple of 

years. The site was excavated only to the normal 

water level to avoid excess erosion. 

The cleanup and rehabilitation program restored 

the appearance of the NPRA. By the removal or 

burial of debris, followed by an intensive revegetation program, disturbance to the environment has 

been minimal. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C75 
What is the story of 

the Barrow gas fields? 

Gas was discovered at Barrow in April 1949, and 

the fields hold two records: the South Barrow gas 

field is the oldest producing field in Alaska, and the 

South and East Barrow fields are the farthest north 

in North America. Barrow No. 2, the discovery well 

for the South Barrow field, was drilled during the 

U.S. Navy's Pet-4 program. 

The base camp for the Pet-4 exploration program was located about 4 miles along the beach 

from the village of Barrow. This camp evolved into 

the Naval Arctic Research Laboratory (NARL) It 

was decommissioned in 1981 and was used only as 

a base for the gas-field operations, but it is still 

generally called "the NARL." The discovery well 

was located about 4 miles southeast of the village 

and approximately 5 miles south of the base camp. 

The camp was fueled by oil brought in by barge 

once a year, until gas was piped from the well into 

the camp. The camp was completely converted to 

natural gas by winter 1949-50. 

C76 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

When the Pet-4 exploration program began, 

there were about 400 inhabitants at Barrow, a community that consisted of a cluster of some SO houses 

and buildings. The program provided opportunities for the Eskimos to work for cash wages, 

many for the first time. Employment opportunities 

attracted additional inhabitants, and the population 

of Barrow increased rapidly. Good airport facilities 

and improved communications, byproducts of the 

exploration program, made Barrow easily accessible and a rather desirable place to live, so far as 

amenities were concerned. 

The relative conveniences of Barrow, together 

with its burgeoning Native population, prompted 

several Federal agencies to establish offices in the 

village, generally in the form of compounds. These 

agencies requested the use of natural gas, and so, in 

1958, gas was piped into the village and connected 

to the various compounds, so that they, too, had the 

use of this superior fuel. The Native inhabitants 
quickly saw the advantages of natural gas and petitioned the Congress for permission to use it. The 

Congress passed favor ably on their petition, and by 

1965 Barrow had completely converted to natural 

gas. The abundant cheap fuel attracted additional 

people, and the U.S. Navy slowly developed the 

South Barrow gas field to its present size (six producing wells) in response to the growing demand. 

The gas produced from the Barrow fields is about 

95 percent methane. 

Panoramic view of the Barrow settlement, late summer 1924. Photograph by Phillip S. Smith. 

In 1974, dwindling reserves of gas in the South 

Barrow field caused the Navy to drill Barrow No. 12, 

an exploratory well located about 6 miles east of the 

original field. The location of this well was based on 

a seismic survey of the area in 1973. The well 

penetrated the reservoir sand but did not produce 

at commercial rates. In early spring 1977, Barrow 

No. 14 was completed and proved to be a good gas 

well. It is about half a mile east of Barrow No. 12 in 

what is now called the East Barrow gas field. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C77 
Aerial photograph of Barrow, probably taken in 1963 before completion of the gas-distribution system. Larger buildings are part of 

Federal compounds: the U.S. Weather Service (right foreground), the 

Bureau of Indian Affairs (background), and the Public Health 

Service (background). View northeastward. Photograph by john 

Schindler. 

Thousands of oil-filled barrels were delivered to Barrow by barge 

during the Pet--4 program in 1944-53. 

C78 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

Barrow, 1983. The most recent census counted about 3,500 people as 

year-round residents. Photograph by Robert Lantz. 
The role of the USGS at 

Barrow 

Gas from the South Barrow field was supplied to 

the townspeople at a subsidized price, and no limits 

were imposed on its use. Over the years, the entire 

Barrow community has become completely dependent on Barrow gas as the source of heat and 

power-necessities in this cold, harsh climate. 

The Naval Petroleum Reserves Production Act of 

1976 (Public Law 94-258) transferred jurisdiction 

of NPR-4 from the Secretary of the Navy to the 

Secretary of the Interior, effective June 1, 1977. That 

law directed the Secretary of the Interior to 

"develop and continue to produce the South Barrow gas field or other such fields as may be necesOld gas-distribution system on barrels. Photograph by Carroll 

Livingston. 

sary to supply gas at reasonable and equitable rates 

to the Native village of Barrow and other communities and Federal installations at or near Point Barrow, Alaska." The Secretary of the Interior delegated 

that responsibility to the USGS. The USGS supplied 

natural gas to the Barrow community from June 1, 

1977, until October 1, 1984. 

The Congress passed Public Law 98-366, the 

Barrow Gas Field Transfer Act of 1984, on July 17, 

1984. This law relieved the Secretary of the Interior 

of his responsibility for supplying Barrow and the 

nearby Government installations with natural gas. 

That responsibility was assumed by the North Slope 

Borough on October 1, 1984, in return for $30 

million and title to the gas fields. The USGS is to 

furnish technical assistance to the borough on 

request until October 1, 1989. 

Old gas-di1tribution systrm swpnulfdjiom stawhions. 1'/wlogmph 

by Robrrt Lantz. 

When the Congress approved the sale of gas to the village, a tnnporary 

distribution system was built above ground from material left over 

from the Pet-4 program. Supported on barrel halves or by stanchions, 

it was subject to leaks and accidental breaks. This p!wtograjJh of 

Barrow was taken in 1963 or 1964 during construction of thr 

distribution system. What appear to be fine dotted lines in the foreground are barrel halves awaiting the gasline. This "temporary" 

system was replaced in 1982 ajier some 18 ymrs of service. Photograph by Robert Lantz. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C79 
Gas consumption 

All of the gas produced from the Barrow fields 

was consumed by Federal installations until 1964, 

when gas was also provided to the village. The 

volume of gas used by the village that first year 

(1965) was about 140,000 thousand cubic feet 

(MCF), or about 36 percent of the 388,846 MCF 

that was produced; the other 64 percent was used 

by Federal consumers. The U.S. Navy originally 

charged Barrow $0.50 per MCF but reduced that 

price to $0.324 per MCF in 1976, which is the 

current price. 

When the responsibility for the gas fields passed 

to the USGS in 1977, the village was using a little 

more than half of the gas produced and was just 

beginning a civic improvement program designed 

to elevate the standard of living in Barrow to that of 

a typical small town in the "South 48." The goals--

running water, flush toilets, modern houses with 

Present-day whale hunting at Barrow. Much ritual and ceremony 

are involved. Photograph lry J ohn Schindler. 

modern conveniences--is near reality, powered by 

subsidized natural gas. More than 300 new homes 

have been built in the past 5 years. Floorspace in 

Barrow is estimated to have increased more than a 

hundred fold since 1965 to a present 1.5 million 

square feet. In 1982, the town of Barrow consumed 

925,000MCFofgas, which amounted to 74percent 

of the total volume of gas produced during that year. 

Gas consumption in Barrow increased by 23 percent in 1982 over 1981 and has increased a total of 

660 percent since 1965. 

Federal gas usage, which has remained relatively 

stable over the past 5 years, is divided among several installations; the NARL, the DEW-line radar 

station at Barrow, the Public Health Service Hospital, the Federal Aviation Administration, the 

National Oceanic and Atmospheric Administration 

(NOAA) Observatory, the Post Office, and the 

National Guard Armory. Of these installations, the 

NARL is by far the largest consumer. 

Winter view of Barrow, before the advent of the Pet-4 program. 

Houses shown are probably typical of the time. lJ you look closely, you 

will see 17 dogs hooked to the sled. Dog teams have now been almost 

completely replaced lry snowmobiles. Photograph lry Charles Brower. 

Eskimo house at Barrow in the 1920's. In the old Eskimo culture ,fuel 

in the Barrow area consisted mostly of driftwood, animal oil, and 

moss, although coal, oil shale, and oil from the seeps were used at 

times. Fuel was crucial to survival. Homes were small. The sources of 

heat and light--the cook stove and oil lamp--were the centers of 

indoor activities and family social life. Photograph lry Charles 

Brower. 

CSO THE NATIONAL PETROLEUM RESERVE IN ALASKA 
Gas production 

On October 1, 1984, operation of the gas fields at 

Barrow was taken over by the North Slope Borough. Before that date, the gas fields were operated 

and maintained by a contractor under USGS supervision. This contractor was based at the old NARL 

camp that the U.S. Navy decommissioned in 1981. 

The NARL is a large installation and requires 

considerable maintenance in the harsh climate. The 

camp is by necessity a standalone operation. There 

are no public utilities to furnish water supply, 

sewage treatment, or electricity; all such services 

must be handled within the camp. The gas-field 

road network also requires the almost constant use 

of several pieces of heavy equipment. 

When the USGS supervised the operation, the gas 

fields themselves were constantly watched by gasfield operators aided by a remote monitoring system installed in 1982. Every effort was made to 

ensure an uninterrupted flow of gas. It was a sizable 

task, requiring a workforce of about 35 people and 

costing about $6 million a year. 

Aerial views of Banow taken frmn nearly the same position about 20 

years apm t (upper, 1963; lower, 1983). Growth in the number and 

size of homes is readily apparent and explains Banow's soaring 

demandf or gas. The cluster of buildings in the U.S. Weather Service 

compound (right f oreground) remains about the same. Photographs 

by Robert Lantz and j ohn Schindler. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA CSl 
The Barrow gas fields themselves are rather typical except for their location and the pervasiveness 

of permafrost. Permafrost in the area of the producing fields extends from the surface down to about 

1,000 feet. The annual mean temperature at Barrow 

is about l0°F, and ice is a constant hazard. Water 

produced with the gas could accumulate in the 

wells, flowlines, or transmission lines, freeze, and 

cut off the flow of gas. The wells are not deep; the 

reservoir sand is above 2,500 feet, and the reservoir 

temperature is approximately a cooi60°F. The wells 

are produced in a peculiar manner to utilize the 

cold permafrost that surrounds the upper part of 

the well bore, so as to minimize the amount of water 

produced with the gas. Barrow gas flows through 

the annular space between the 7 -inch-diameter casing and the 27

/s-inch-diameter tubing. In most wells, 

gas flows through the tubing, but because the crosssectional area of the annulus greatly exceeds that of 

the tubing, a given volume of gas will travel much 

slower through the annulus. Thus, as Barrow gas 

flows slowly up through the freezing temperature 

of the permafrost, much of the water freezes out of 

the gas and falls to the 'bottom of the well. The 

tubing is only used to clean the accumulated water 

out of the wells. Alcohol is also injected into the gas 

stream to reduce still further the chances of ice 

blocking the flow of gas. 

"Blowing" a well. Water vapor produced with the gas freezes out of 

the slow-moving gas and accumulates in the bottom of the well. To 

clean out the water, the flow of gas is diverted to the tubing, and the 

well is opened to the atmosphere. The gas flowing against only 

atmospheric pressure through the small-diameter tubing ttain~ a 

high velocity and carries the water to the surface. The water is 

discharged into the air as vapor, forming a plume. Photograph by 

Robert Lantz. 

fw 1000 w 

u.. 

~ 

£ 1200 

fa.. 

w 

0 

1600 

1800 

2200 

2400 b-----------------------------------~ 

Detailed d1·illing, cementing, and casing program/(1r t1 tV/Jim / t~

row gas well. A 13 %-inrh-diamPin ronductor pipe is .11'/ t1/ dt/Jih o/ 

about 80 Jet! and cnnmted to the s111[t1a. A 12 111-inriHiifiJJII'Itr hole 

is drilled to approximately I ,500 fn'l; 9'/x-inch-diametn m1i11g is .\1'/ 

in the hole and cemmted to the .11nj{Jce. A11 8 1/2-inrh-diwlleln holt' is 

drilled through the reservoir, in which 7-inrh -dirulltln rflsill!; is ru u 

and cemented to the tojJ o/ the cn11 mt left a/ alum/ I ,200:/i't'l dt/Jtli, 

which is below the jJrnnafi·ost. Abuw 1,200fttl, tht wt/1 is tlrclir 

packed (arctic f)(lck is a nonfreezing Ct'!l!t'n / substilule). Tht' 2 '/s-iurhdiameter tubing is hung inside the 7-inch-diru//e/er wsing, which is 

perforated into the reservoir rock and thus allows !ht' gt~s /o tnln !Itt' 

well. The gas is produad through the annu /m· spaa be!wten tht 7-

inch-diameter casing and the 27/s-inrh-diaml'lt'r tubiug. 

H eaters at the East Barrow gas-production facility, where cold gas 

from the well is heated before the pressure is reduced. Pt1ssage of highpressure gas through a restrictive orifice ("choke" in gas-field language) to reduce the pressure results in a large temperature drop that 

could freeze water associated with the gas and cause blockage of the 

line. Heating the gas before choking prevents freezeujJs. Photogmph 

by Robert Lantz. 

C82 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
Gas from the individual wells goes through 

flowlines to a central producing facility located in 

each of the fields, where the gas pressure is reduced 

and regulated at a transmission pressure of about 

225 pounds per square inch. The gas is also 

metered before entering the transmission lines that 

carry it to Barrow or the NARL. 

Interior" of a wellhouse in the East Barrow gas field, showing a typical 

wellhead or "Christmas tree" through which the gas is produced. The 

wellhouses are heated and provide a relatively comfortable environment for the workers. Photograph by Robert Lantz. 

Flowlines at the East Barrow gas-productionfaci/ity. Photograph by 

David Fears. 

Manifold where the flowlines enter the East Barrow metering and 

regulation (M&R) building. Photograph by Robert Lantz. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C83 
View of the piping inside the M & R building at South Barrow. 

Photograph by Robert Lantz. 

C84 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

Flowlines into the central production facility in the older South 

Barrow gas field . Note the confusing, interconnected piping, threaded 

connections, and valving exposed to the weather. The South Barrow 

production facility and gathering system were largely built on site 

from surplus materials. As the number of gas wells increased, valves 

and pipes were aclded to accommodate them. The operators said "it 

just grew like Topsy." Photograph by David Fears. 
Prospects for supplying 

future demands 

The South Barrow gas field originally contained 

about 27 billion cubic feet (BCF) of recoverable 

reserves, and the East Barrow field about 8 BCF. The 

gas accumulations in the South and East Barrow 

fields are on the rim of an approximately circular 

area containing chaotic structures, which the U.S. 

Navy called the "disturbed zone." Seismic surveys 

in the area of the disturbed zone indicate the presence of an additional untested rim structure, about 

the same size as the one at East Barrow, which, if 

filled with gas, might contain as much as 10 BCF of 

gas. Another structure is about 7 miles south of the 

South Barrow field, near old Barrow No. 3-a dry 

hole completed by the Navy in late August 1949. 

This small structure, if filled with gas, might also 

contain as much as 10 BCF. 

About 15 miles south of Barrow, a gas accumulation of unknown dimensions was discovered by the 

Walakpa No. 1 well, drilled by the USGS in February 

1980. A confirmation well, Walakpa No. 2, about 5 

miles southwest of No. 1, was completed in February 1981. Both wells were tested extensively The 

Known gas fields in the Barrow area (shown in red). The areal extent 

of the Walakpa field is unknown. Contours show configuration of the 

Barrow gas sand in reference to a level plane (sea level). Heavy lines 

denote faults; D (down) and U (up) show relative positions of rocks on 

each side of the faults. Schenwtic cross sections through the gas fields 

are drawn along green lines A-B (Barrow fields) and C-D (Walakpa 

field). 

gas is contained in a stratigraphic trap formed by 

updip pinchout of the reservoir sand to the north, 

but additional drilling will be necessary to establish 

the lateral (east-west) boundaries of the field. The 

downdip (south) producing limit is also unknown; 

although the Walakpa No. 2 well is more than 500 

feet deeper than the discovery well, it did not reach 

the lower limit of the gas field. The Walakpa gas field 

could contain a significant volume of gas if the trap 

is of large dimensions, as is presently believed. 

As can be gathered from this discussion, the total 

volume of producible gas in the sparsely drilled 

Barrow district is not known with any accuracy. 

Basement rocks are closer to the surface at Barrow 

than anywhere else on the North Slope, and the 

rocks slope away from the Barrow high in all direc 

tions. All the wells drilled in the area to date have 

had some shows of gas, but reservoir rocks are 

scarce, and without an adequate reservoir, commercial production is impossible. 

1 2 3 MILES 

I 1 1 I I 

0 1 2 3 KILOMETERS 

THE NATIONAL PETROLEUM RESERVE IN ALASKA CBS 
The A three known gas accumulations are all less 

than 3,000 feet deep. The South and East Barrow 

fields, though not connected, produce from the 

same stratigraphic horizon-the Barrow sand. The 

Walakpa field produces from the Walakpa sand, 

slightly younger and a little above the Barrow sand 

in the stratigraphic section. Both sands have limited 

distribution, are of Mesozoic age, and have similar 

reservoir properties. 

f--- -South Barrow - --+---------Oi,sturbed zone ---------1------East Barrow-----1 

Cretaceous rocks Mesozoic rocks undifferentiated 

Possibly because it occupies the highest structural position in the area, the Barrow district 

appears to be gas prone. Oil in commercial quantities has not been found, although some was 

recovered from thin sand of Cretaceous age in the 

Barrow No. 20 well. 

Schematic cross section through the South and East Barrow gasfu•lds 

along line A-B. This cross section illustrates what petroit'l/111 

geologists call a "trap. " Oil and gas are lighter thau water and thw 

will migrate upward until they are "trapped" in a place from whirh 

they cannot escape. The South and East Barrowfields are st,·uctural 

traps-ihe rocks slope away in all directions, and thr hydrorarbon' 

are trapped in the highest part of the arch, or structw·e. In contrast, 

the Walakpafield, shown in cross section below, is an example !if· a 

stratigraphic trap. Disappearance of the Walakpa sand (reservoir) 

updip traps the hydrocarbons when they have migrated as far up thr 

reservoir as possible. 

c Walakpa No. 2 

Mesozoic rocks undifferentiated 

Schematic cross section through the Walakpa gas field along line 

C-D. The Barrow sand, reservoir rock of the Barrow gas fields, is 

present in the Walakpa area but does not form a trap and contains 

only water. The Walakpa gas field has not been developed and luu 

produced no gas except for a small amount during testing of the two 

wells. 

C86 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

Jurassic rocks 

Cretaceous rocks 

Jurassic rocks 

Walakpa No. 1 D 

Triassic rocks 
The USGS' accomplishments 

at Barrow 

When the USGS was assigned the responsibility 

of providing gas to the Barrow community, only the 

South Barrow field was equipped with the facilities 

necessary to produce gas and with the pipeline 

connections required to transport the gas to consumers. The East Barrow field consisted of one well 

but was without producing facilities or pipeline 

connections. There were no roads to the fields, and 

the environmental degradation resulting from 28 

years of operating the South Barrow field without 

roads was deplorable. The ratio of remaining producible gas to gas consumption was below normal 

standards, and gas consumption was increasing 

rapidly. 

The first priority was to find out whether the East 

Barrow field contained sufficient gas to justify construction of a pipeline and production facilities. 

Two wells were drilled during the first winter of 

operation (1977- 78 ) Barrow No. 17 was drilled 

more than a mile west of the existing well (Barrow 

No. 14 ); it penetrated the gas-water contact and 

established the field-producing limit. Barrow No. 

19 was drilled northeast near the crest of the structure, to determine the reservoir characteristics. 

The wells were extensively cored and tested to 

obtain the maximum data. Calculations based on 

this new information indicated that sufficient gas 

was present to justify construction of production 

facilities and pipelines, because operation of the 

new field would nearly double existing reserves. 

Construction of the road between the Barrow gas fields. What appear 

to be large boulders along the shoulder are frozen blocks of gravel. The 

equipment is operating on an ice road alongside the gravel road. This 

ice road was built to speed construction; it disappeared with the spring 

thaw. To conserve gravel the road is one lane wide, with wider spots 

every quarter-mile to allow vehicles to pass; even so, about half a 

million cubic yards of gravel was required for the gas-field roads. 

Photograph by Robert Lantz. 

Part of the 6-inch-diameter pipeline from the East Barrow gas field. 

Expansion loop (center) allows the steel pipe to expand and contract 

without breaking. The pipe is anchored midway between the expansion loops, which are spaced at regular intervals to avoid any large 

accumulated movement. The pipeline is supported above ground on 

wood piling. The taller supports now carry electricity to the East 

Barrow fie ld. Photograph by Robert Lantz. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C87 
With this positive information in hand, work 

began at once. Three additional wells were drilled, 

although one (Barrow No. 20) was damaged during 

cementing operations and could not be completed 

as a gas well. An all-weather gravel road was constructed to the gas fields to end the environmental 

damage associated with gas-field operations. A 

pipeline was built to carry the gas from the East 

field to the South field. The old South Barrow producing facility was inspected, and some needed 

safety features were added. A remote monitoring 

system was installed. Larger well houses and 

flowlines were installed at East Barrow than had 

been used at the South Barrow field, for added 

safety and reliability. Emergency electrical generating equipment was installed in the gas field as an 

additional safeguard against interruption of the flow 

of gas. The East Barrow gas field was brought into 

production in 1981. 

While the gas fields were assigned to the USGS, 

the producible reserves of gas were increased several times over. A road network was built to minimize environmental damage. Automatic valving 

and electrical generating equipment, as well as a 

state-of-the-art producing facility at the East field, 

were installed. Installation of a system that permits 

remote monitoring of all key points in the entire 

producing system and all well houses resulted in a 

much safer operation and a more reliable supply of 

gas. The Walakpa gas field was discovered-a field 

that could contain sufficient gas to supply the 

energy needs of the Barrow community well into 

the 21st century. 

The current status of all important functions at 

each well and at each M & R station is checked several times each 

minute by electronic devices (left) and displayed on a computer terminal located in the office (right). The system automatically sounds an 

alarm, accompanied by a flashing light that indicates what is wrong, 

as soon as it senses f altering well or production-system performance. 

The monitoring system normally operates over telephone lines, but it 

has a radio backup should the telephone lines fail. Automatic shutoff 

valves have been installed on the transmission lines, and on wells 

where possible, to make operating the gas fields much safer. Photograph by David Fears. 

C88 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

A remote monitoring system was recently installed to assure an uninterrupted flow of gas. 
What is happening 

with the leasing of 

NPRAlands? 

What is the leasing 

program? 

Leasing of lands in the NPRA commenced shortly 

after the Congress authorized private oil and gas 

exploration and development of the Reserve in the 

Supplemental Appropriations Act (Public Law 

96-514) ending fiscal year 1981. The provisions of 

that act have shaped the BLM's leasing policy. Five of 

these provisions are: 

( 1) activities in the NPRA will be environmentally sound; 

( 2) bidding is to be based on the bidding systems used for large offshore tracts; 

( 3) the size of a tract may not exceed 60,000 

acres; 

( 4) primary leasing term will be 10 years and 

will be extended so long as paying quantities 

of oil and gas are produced, and 

( 5) half of the leasing receipts are to go back to 

the State of Alaska. 

Some of these provisions were unusual in comparison with the regular leasing procedures set for 

other onland areas of the United States. Because of 

the vast size of the Reserve (the second lease sale of 

3.5 million acres was the largest Federal offering in 

history), the BLM was required to use the same 

leasing technique that is used for large offshore 

Generally, the leadup to an NPRA lease sale is a 

four-part process. First, there is a period of exploration and information gathering; then, private companies are asked to submit nominations and 

comments about interest areas. The BLM then 

selects the location and size of the tracts, and identitracts. For offshore lease sales, private companies 

submit sealed bids; for onland sales, the BIM determines a fixed price for each tract, and the names of 

private companies are drawn from a lottery. Also, 

owing to the large tract size, the Congress determined that the environmental-impact statement 

completed in 1977 for the entire NPRA satisfied the 

Environmental Protection Agency's requirements 

for the first two sales of as much as 2 million acres. 

In most cases, the private company is to provide the 

1

environmental-impact statement for each leased 

tract. 

The NPRA is an ecologically sensitive area, and 

the subsistence of many Native people is intimately 

tied to its ecology. In addition to developing regulations protecting the NPRA, the BIM staff gathered 

new information by visiting North Slope villages. 

Through public meetings and questionnaires, the 

BIM hoped to identify additional criteria of concern to the Native people. A list of possible leasing 

strategies, covering a broad range of environmental 

ideas, was presented for public comment. The BLM 

hoped that by working with the public, a management strategy could be devised that would "best 

mitigate impacts on the values of the reserve." 

fies any special environmental regulations for each 

area. Finally, on a certain scheduled day, the actual 

lease sale is held. 

Four lease sales have been offered to date: 

December 1981, May 1982, July 1983, and July 

1984. A fifth sale is scheduled for July 1985. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C89 
Summary of the USGS' 

accomplishments in 

the NPR-4/NPRA 

program 

NPR-4 was set aside in 1923 by Presidential 

order as a potential source of oil for the U.S. Navy. 

The petroleum potential of northern Alaska and the 

outline of the Reserve were based largely on early 

explorations by the U.S. Navy and the USGS, and on 

information collected by other explorers (primarily E. de K Leffingwell) but published by the 

USGS. 

Between 1923 and 1976, the USGS worked cooperatively with the U.S. Navy to further define the 

geologic framework, assess the petroleum and 

other mineral resources, and provide base maps of 

the Reserve. In 1976, the U.S. Congress transferred 

responsibility, renamed the Reserve, and redefined 

the role of the Federal Government. The USGS was 

assigned the responsibility of continuing the exploration program begun by the Navy, maintaining and 

operating the Barrow gas fields, and completing the 

cleanup and rehabilitation of the Reserve and 

adjoining areas. The Federal exploration program 

has now been terminated, and a leasing program has 

begun. 11-ansfer of the Barrow gas fields to the North 

Slope Borough took place October 1, 1984. The last 

stage of the cleanup program was completed in 

summer 1984. 

Throughout the history of NPR-4/NPRA, the 

USGS has carefully documented and made available 

to the public, largely through its own publications, 

all the geotechnical information gained through 

Federal programs. In addition, it has integrated this 

information with private-exploration results outside the NPRA and periodically reassessed the 

petroleum potential and the geologic framework of 

the entire northern Alaska petroleum province and 

the adjacent Continental Shelf These are the only 

Arctic regions within the sovereign domain of the 

United States, and they are among the last frontier 

regions for mineral-resource exploration and 

development. Because of the Arctic climatic and 

geographic setting, the wilderness aspects, and the 

indigenous population, these studies present many 

problems that are unique. The mineral-resource 

and geotechnical-engineering information has been 

utilized by Federal agencies in the management of 

C90 THE NATIONAL PETROLEUM RESERVE IN ALASKA 

these public lands and by industry to explore and 

develop the resources. 

A vast amount of geotechnical information on 

which to base further exploration has been collected and is available in publications and in contractor reports released by the USGS. A few 

examples are listed in the bibliography that follows 

to illustrate some results of the program and the 

kind of information that is available. 

Exploration program and 

hydrocarbon assessment 

• The USGS completed the systematic exploration program as mandated by the Naval Petroleum 

Reserves Production Act of 1976 (Public Law 

94-258) A total of 28 test wells were drilled, 7 

under U.S. Navy and 21 under USGS supervision; 6 

test and development wells were drilled in the 

Barrow gas fields. Nearly 15,000 line-miles of seismic surveys were completed and interpreted, in 

addition to the more than 3,000 line-miles completed in the Pet-4 program from 1943 to 1953, 

which were reinterpreted and integrated into the 

new surveys. 

• Subsurface samples, cores, and cuttings were 

collected systematically in both the 1943-53 and 

197 4-82 programs. Because of the frontier nature 

of the region and the emphasis on a regional evaluation, a larger than usual number of samples were 

collected, curated, and made available for study in 

Anchorage, Alaska. 

• These subsurface samples were studied by specialists in geochemistry, paleontology, petrology, 

and core analysis. The basic data and interpretations resulting from these studies are all available. 

• An original program for an interactive computer-based data and graphics system was designed 

with the aid of contractors and is available to the 

public. This system includes files for base maps, 

daily drilling reports, digitized subsurface logs, seismic shotpoints, outcrop data, geochemical data and 

interpretation, and paleontologic information. 
• Models of the depositional paleoenvironment 

have been developed for sandstones of)urassic and 

Cretaceous age that are the main prospective reservoirs in the NPRA. 

• The first test well in the Foothills thrust belt of 

the NPRA, the Lisburne No. 1 test well, was drilled 

to a depth of 17,000 feet. It penetrated five distinct 

thrust plates, confirming the structural interpretations of the prospect, but no hydrocarbon deposit 

was discovered. 

• Two deep exploratory wells (at the time of 

drilling, the deepest anywhere in Alaska) were 

drilled at Tunalik and Inigok. The Tunalik well 

reached a depth of 20,335 feet and penetrated 

strong blows of gas in a thick section of CretaceousJurassic rocks. The Inigok well, which was drilled to 

20,102 feet to test a deep basement structure, penetrated an unusual and unexpected flow of sulfur and 

hydrogen sulfide. 

• About 15 miles southwest of the Barrow gas 

fields and downslope from the Barrow structural 

high, the Walakpa test well penetrated a new gas 

deposit. A second well extended this discovery, but 

no additional wells were drilled. Thus, the size of 

this field has yet to be determined, although it is 

probably larger than the Barrow fields by a factor of 

10 or more. It could provide gas to the local communities well into the 21st century. 

• Inasmuch as the exploration program was 

aimed at an assessment of the oil and gas potential of 

the entire NPRA, a new approach was developed. A 

total of 17 petroleum plays-areas of geologically 

similar prospects-were delimited, and a program 

to test each was planned and largely completed. 

• For all of these plays, the amount of 

undiscovered crude oil in place is estimated at 0.82 

billion barrels at a 95-percent probability and 15.4 

billion barrels at a 5-percent probability, for an 

average of 5.97 billion barrels. 

• The total amount of undiscovered natural gas in 

place is estimated at 2.4 trillion cubic feet (TCF) at a 

95-percent probability and 27.2 TCF at a 5-percent 

probability, for an average of 11.3 TCF 

• The exploration program has extended and 

refined our knowledge of the geologic framework 

of Arctic Alaska and the adjoining Continental Shelf 

The geologic structural framework is described as 

consisting of three distinct structural provincesthe Arctic platform, the Foothills fold belt, and the 

Brooks Range thrust belt. The stratigraphic section 

is described as consisting of three sequences-the 

Franklinian rocks of pre-Mississippian age, the 

Ellesmerian rocks of Mississippian to early Early 

Cretaceous age, and the Brookian rocks oflate Early 

Cretaceous to Holocene age. 

• Interpretations based on plate tectonics suggest that the Canada Basin of the Arctic Ocean 

formed by rotational rifting of the Arctic platform 

away from the Canadian Arctic Islands during 

Jurassic to Early Cretaceous time, and that the 

southwestward drift of this platform created the 

Foothills fold belt and the Brooks Range thrust belt 

by underthrusting. 

Cleanup, rehabilitation, and 

environmental 

considerations 

• Cleanup of debris left by earlier workers in the 

NPRA and adjoining areas was begun by the U.S. 

Navy in 1971 mainly in and near the Barrow and 

Umiat base facilities. The USGS extended this program, reaching out· to the remote corners of the 

NPRA, and completed the cleanup in 1984. 

Although no precise records exist of the amount of 

debris collected, it totals tens of thousands of tons 

of noncombustible materials and hundreds of thousands of 55-gallon drums-the ubiquitous containers for fuel throughout the remote areas of 

Alaska. 

• For efficiency of operation, cleanup and 

rehabilitation of the earlier sites were combined 

with work on the sites of the 1974-82 exploration 

program. This program involved about 540 of the 

23,680,000 acres of the Reserve, and seismic surveys traversed nearly 15,000 line-miles. Except for 

permanent runways, these areas will return to a 

near-natural state within a few years. 

• To maintain minimum environmental impact, 

the USGS agreed with the land managers-the 

BLM--on a system for advance planning, stipulations, and monitoring that set a standard for such 

cooperation on Federal lands in northern Alaska. 

• Environmental stipulations mutually agreed 

upon by the BLM and the USGS have been carefully 

monitored by both agencies and by their contractor personnel, and impacts were maintained at 

an acceptable level. 

• A thin-pad design for one-season winter drilling proved to be environmentally preferable and 

more cost effective than a thick-pad design. Thin 

pads are more quickly assimilated into the natural 

surroundings than are thick pads. 

• Ice roads, properly constructed, proved to be 

practical and cost effective, and had little or no 

visible effect on the tundra. 

• Ice airstrips on lakes or constructed by flooding on shallow ponds or marshes proved to be 

practical and cost effective, and had no adverse 

environmental impacts. 

• Preclearance for environmental, cultural, and 

archeologic reasons was required and was carried 

out for all active sites. These surveys and studies 

contributed much valuable information on archcologie sites. 

THE NATIONAL PETROLEUM RESERVE IN ALASKA C91 
Operation and maintenance 

of the Barrow gas fields 

• The USGS operated and maintained the Barrow 

gas fields for the benefit of the Barrow communities 

and Federal Government installations until 

October 1, 1984. 

• The East Barrow gas field was discovered by the 

U.S. Navy in 1974, but it remained for the USGS to 

prove the development potential, complete the 

facilities, and bring the field into production. Both 

reserves and delivery are expected to meet anticipated demand at least through 1989. 

• The USGS discovery of a new gas field at Walakpa provides the possibility for extended use of gas 

as the main energy source for the Barrow communities beyond the year 2000. 

• The USGS completed a thorough testing program-the first in the history of the fields--to establish reserve limits, individual well capabilities and 

characteristics, and maximum safe-delivery rates. 

• A modernization program was begun to help 

reduce costs and to increase safety and efficiency 

All-season gravel roads were constructed to vital 

facilities, not only to increase effective operation 

and safety, but also to reduce environmental 

impacts caused by repeated vehicular traffic over 

the surrounding tundra. 

• Public Law 98-366, the Barrow Gas Field Transfer Act of 1984, relieved the Secretary of the Interior (and, thus, the USGS) of the responsibility for 

supplying natural gas to the Barrow community, 

effective October 1, 1984. The entire gas system is 

now operated by the North Slope Borough. The 

USGS is to furnish technical assistance to the borough until October 1, 1989. 

Termination of the NPRA 

program 

• In 1982, the NPRA program of the USGS was 

terminated. The BLM now has the overall responsibility for management and protection of the land 

within the Reserve. In accordance with the MOU, 

the USGS has completed its responsibilities, and the 

area has been returned to the BLM. The project has 

exemplified how a good working relationship 

between Government and industry, as well as cooperation of two larger government agencies--the 

BLM and the USGs---<:an serve to safeguard the best 

interests of all concerned. 

C92 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
References cited 

Bird, K. ]., 1981, Petroleum exploration of the North Slope in 

Alaska, U.S.A.: U.S. Geological Survey Open-File Report 

81-227, 43 p. 

Bowsher, A. L., and Dutro,]. T,Jr., 1957, The Paleozoic section in 

the Shainin Lake area, central Brooks Range, Alaska: U.S. 

Geological Survey Professional Paper 303-A, p. 1-39. 

Brooks, A. H., 1909, Petroleum in the mining industry in 1908: 

U.S. Geological Survey Bulletin 379-A, p. 21-62. 

Chapman, R. M., and Sable, E. G., 1960, Geology of the 

Utukok-Corwin region, northwestern Alaska: U.S. Geological Survey Professional Paper 303-C, p. 47-167. 

Collins, F. R., 1958, Test wells, Meade and Kaolak areas, Alaska, 

with a section on Micropaleontology of Meade test well 1 

and Kaolak test well 1, northern Alaska, by H. R. Bergquist: 

U.S. Geological Survey Professional Paper 305-F, p. 

341-376. 

--- 1958, Test wells, Topagoruk area, Alaska, with a section 

on Micropaleontologic study of the Topagoruk test wells, 

northern Alaska, by H. R. Bergquist: U.S. Geological Survey 

Professional Paper 305-D, p. 265- 316. 

--- 1958, Test wells, Umiat area, Alaska, with a section on 

Micropaleontologic study of the Umiat field, northern 

Alaska, by H. R. Bergquist, and sections on Temperature 

measurement studies, by M. C. Brewer, and Core analyses, 

Umiat test well 9, by G. L. Gates: U.S. Geological Survey 

Professional Paper 305-B, p. 71-206. 

--- 1959, Test wells, Square Lake and Wolf Creek areas, 

Alaska, with a section on Micropaleontology of Square 

Lake test well No. 1 and the Wolf Creek test wells, northern 

Alaska, by H. R. Bergquist: U.S. Geological Survey Professional Paper 305-H, p. 423-484. 

---1961, Core tests and test wells, Barrow area, Alaska, with 

a section on Temperature measurement studies, by M. C. 

Brewer: U.S. Geological Survey Professional Paper 305-K, 

p. 569-644. 

Drilling Department, 1983, Design and construction of the Walakpa Test Well No. 2: Anchorage, Alaska, Husky Oil NPR 

Operations, Inc., 52 p. 

Ferrians, 0. ]., Jr., Kachadoorian, Reuben, and Greene, G. W., 

1969, Permafrost and related engineering problems in 

Alaska: U.S. Geological Survey Professional Paper, 678 p. 

Gryc, George, Miller, D.J., and Payne, T G., 1951, Alaska, in Ball, 

M. W., ed., Possible future petroleum provinces of North 

America: American Association of Petroleum Geologists 

Bulletin, v. 35, no. 2, p. 151-168. 

Haugen, R. K., and Brown, Jerry, 1971, Nature and man-induced 

disturbances of permafrost terrain, in Environmental geomorphology: Binghamton, State University of New York, p. 

139-149. 

Hewitt, S. L., 1983, Design and construction of the Lisburne Test 

Well No. 1: Anchorage, Alaska, Husky Oil NPR Operations, 

Inc., 26 p. 

Keller, A. S., Morris, R. H., and Detterman, R. L., 1961, Geology of 

the Shaviovik and Sagavanirktok Rivers region, Alaska: U.S. 

Geological Survey Professional Paper 303-D, p. 169-222. 

Lachenbruch, A. H., 1970, Some estimates of the thermal effects 

of a heated pipeline in permafrost: U.S. Geological Survey 

Circular 632, 23 p. 

Leffingwell, E. de K., 1919, The Canning River region, northern 

Alaska: U.S. Geological Survey Professional Paper 109,251 

p. 

Mertie, ]. B., Jr., 1979, Monazite in the granitic rocks of the 

Southeastern Atlantic States--an example of the use of 

heavy minerals in geologic exploration: U.S. Geological 

Survey Professional Paper 1094, 79 p. 

Miller, D.]., Payne, T. G., and Gryc, George, 1959, Geology of 

possible petroleum provinces in Alaska, with an Annotated bibliography, by E. H. Cobb: U.S. Geological Survey 

Bulletin 1094, 131 p. 

Mitchell, D. W., 1983, On-tundra ice airstrips in NPRA: 

Anchorage, Alaska, Husky Oil NPR Operations, Inc., 22 p. 

--- 1983, Design ofNPRA winter drilling pads, 1976-1978: 

Anchorage, Alaska, Husky Oil NPR Operations, Inc., 9 p. 

---1983, Design ofNPRA winter drilling pads, 1979-1981: 

Anchorage, Alaska, Husky Oil NPR Operations, Inc., 9 p. 

National Petroleum Reserve in Alaska Task Force, 1978, Ecological profile: Anchorage, U.S. Department of the Interior 

(National Petroleum Reserve in Alaska Task Force Study 

Report 4), 118 p. 

Patton, W. W.,Jr., 1957, A new upper Paleozoic formation, central 

Brooks Range, Alaska: U.S. Geological Survey Professional 

Paper 303-B, p. 41-45. 

---1964, Petroleum and natural gas in Northern and Interior 

Alaska, in Mineral and water resources of Alaska: Washington, U.S. Geological Survey report to U.S. Senate Committee on Interior and Insular Affairs, p. 62-77. 

Patton, W. W., Jr., and Matzko,].]., 1959, Phosphate deposits in 

northern Alaska: U.S. Geological Survey Professional Paper 

302-A, p. 1-17. 

Reed, J. C., 1958, Exploration of Naval Petroleum Reserve No. 4 

and adjacent areas, northern Alaska, 1944-53; part 1, History of the exploration: U.S. Geological Survey Professional 

Paper 301, 192 p. 

Rickwood, F. K., 1970, The Prudhoe Bay field, in Proceedings of 

the Geologic Seminar on the North Slope of Alaska: Los 

Angeles, American Association of Petroleum Geologists, p. 

Ll-Lll. 

Robinson, F. M., 1956, Core tests and test wells, Oumalik area, 

Alaska, with a section on Paleontology of test wells and 

core tests in the Oumalik area, Alaska by H. R. Bergquist: 

U.S. Geological Survey Professional Paper 305- A, p. 1-70. 

--- 1958, Test well; Grandstand area, Alaska, with a section 

on Micropaleontologic study of Grandstand test well 1, 

northern Alaska, by H. R. Bergquist: U.S. Geological Survey 

Professional Paper 305"-E, p. 317- 339. 

--- 1958, Test wells, Gubik area, Alaska, with a section on 

Micropaleontologic study of the Gubik test wells, northern Alaska, by H. R. Bergquist: U.S. Geological Survey Professional Paper 305-C, p. 207- 264. 

--- 1959, Test wells, Simpson area, Alaska, with a section on 

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--- 1959, Test wells, Titaluk and Knifeblade areas, Alaska, 

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U.S. Geological Survey Professional Paper 302-B, p. 

19-58. 

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thesis of the western Brooks Range, northwestern Alaska: 

U.S. Geological Survey Open-File Report 83-779, 57 p. 

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THE NATIONAL PETROLEUM RESERVE IN ALASKA C93 
Dusk over East Barrow. Photograph by Robert Lantz. 

C94 THE NATIONAL PETROLEUM RESERVE IN ALASKA 
This report is the third in a series of Earth-Science Special Reports 

being prepared by the U.S. Geological Survey to provide the public 

with timely and useful information on earth-science considerations relative to critical land, mineral, and water-resource issues 

that currently face the Nation.