Prudhoe Bay Oil Field is a large
oil field
A petroleum reservoir or oil and gas reservoir is a subsurface accumulation of hydrocarbons contained in porous or fractured rock formations.
Such reservoirs form when kerogen (ancient plant matter) is created in surrounding rock by the presence ...
on
Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
's
North Slope. It is the largest oil field in North America, covering and originally containing approximately of oil.
[Prudhoe Bay Fact Sheet](_blank)
. BP. August 2006. (Adobe Acrobat *.PDF document) The amount of recoverable oil in the field is more than double that of the next largest field in the United States by acreage (the
East Texas oil field
The East Texas Oil Field is a large oil and gas field in east Texas. Covering and parts of five counties, and having 30,340 historic and active oil wells, it is the second-largest oil field in the United States outside Alaska, and first in tot ...
), while the largest by reserves is the
Permian Basin (North America)
The Permian Basin is a large sedimentary basin in the southwestern part of the United States. The basin contains the Mid-Continent oil province, Mid-continent oil field province. This sedimentary basin is located in western Texas and southeast ...
. The field was operated by
BP; partners were
ExxonMobil
ExxonMobil Corporation (commonly shortened to Exxon) is an American multinational oil and gas corporation headquartered in Irving, Texas. It is the largest direct descendant of John D. Rockefeller's Standard Oil, and was formed on November 30, ...
and
ConocoPhillips
ConocoPhillips Company is an American multinational corporation engaged in hydrocarbon exploration and production. It is based in the Energy Corridor district of Houston, Texas.
The company has operations in 15 countries and has production in ...
until August 2019; when BP sold all its Alaska assets to Hilcorp.
Location
The field is located north of
Fairbanks and north of
Anchorage
Anchorage () is the largest city in the U.S. state of Alaska by population. With a population of 291,247 in 2020, it contains nearly 40% of the state's population. The Anchorage metropolitan area, which includes Anchorage and the neighboring Ma ...
, north of the
Arctic Circle
The Arctic Circle is one of the two polar circles, and the most northerly of the five major circles of latitude as shown on maps of Earth. Its southern equivalent is the Antarctic Circle.
The Arctic Circle marks the southernmost latitude at w ...
, and south of the
North Pole
The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is the point in the Northern Hemisphere where the Earth's axis of rotation meets its surface. It is called the True North Pole to distinguish from the Mag ...
.
It is on the
North Slope and lies between the
National Petroleum Reserve–Alaska
The National Petroleum Reserve in Alaska (NPRA) is an area of land on the Alaska North Slope owned by the United States federal government and managed by the Department of the Interior, Bureau of Land Management (BLM). It lies to the west of the ...
to the west and the
Arctic National Wildlife Refuge
The Arctic National Wildlife Refuge (ANWR or Arctic Refuge) is a national wildlife refuge in northeastern Alaska, United States on traditional Gwich'in lands. It consists of in the Alaska North Slope region. It is the largest national wildli ...
to the east.
Leasing
The State of Alaska owns the land and leases the area as the Prudhoe Bay Unit.
[Staff, ]Alaska Oil and Gas Conservation Commission The Alaska Oil and Gas Conservation Commission (AOGCC) is a quasi-judicial agency in the U.S. state of Alaska, within Alaska's Department of Administration. It was originally established in 1955, was subsequently abolished, but was eventually reesta ...
.
Oil and Gas Pools – Statistics Pages
Accessed April 14, 2013 In the terminology that the State of Alaska uses in its leasing program, the "Prudhoe Bay Oil Field" is called the Prudhoe Bay Oil Pool.
[ Oil pools within the Prudhoe Bay Unit include the following – maps showing the location of each pool are in the associated reference.
]
History
The area was originally identified as a potential oil field and selected in the early 1960s as part of the 100 million acres the federal government allotted to the new state of Alaska under the Alaska Statehood Act
The Alaska Statehood Act () was a statehood admission law, introduced by Delegate E.L. Bob Bartlett and signed by President Dwight D. Eisenhower on July 7, 1958, allowing Alaska to become the 49th U.S. state on January 3, 1959. The law was the ...
as a form of economic support. Tom Marshall, a key state employee tasked with selecting the 100 million acres, said the geology reminded him of big oil basins he'd seen in Wyoming. Commercial oil exploration started in Prudhoe Bay
Prudhoe Bay is a census-designated place (CDP) located in North Slope Borough in the U.S. state of Alaska. As of the 2010 census, the population of the CDP was 2,174 people, up from just five residents in the 2000 census; however, at any give ...
area in the 1960s and, after a number of fruitless years, a rig produced a natural gas flare in December 1967. The oil field was confirmed on March 12, 1968, by Humble Oil
Humble Oil and Refining Co. is a defunct American oil company founded in 1911 in Humble, Texas. In 1919, a 50% interest in Humble was acquired by the Standard Oil of New Jersey which acquired the rest of the company in September 1959. The Humbl ...
(which later became part of Exxon) and Atlantic Richfield Company
ARCO ( ) is a brand of gasoline stations currently owned by Marathon Petroleum after BP sold its rights. BP commercializes the brand in Northern California, Oregon and Washington, while Marathon has rights for the rest of the United States an ...
(ARCO), with the well Prudhoe Bay State #1.[ ARCO was the operating partner. Drilling sites for the discovery and confirmation wells were staked by geologist ]Marvin Mangus
Marvin Dale Mangus (1924–2009) was an American geologist and landscape painter. He was giving the honor of driving a purely symbolic wood stake prior to start of drilling the actual oil well by the Atlantic Richfield Corporation, his employer. ...
. BP was among the companies that had been active in the region, and BP was able to establish itself as a major player in the western part of the Prudhoe field. The field was initially operated as two separate developments, the BP Western Operating Area and the ARCO Eastern Operating Area. Upon acquisition of ARCO by BP and sale of ARCO Alaska assets to Phillips Petroleum in 2000, the two operating areas were consolidated and BP became the sole operator of the field.[International Mapping on behalf of BP]
BP in Alaska, animated map
In 1974 the State of Alaska's Division of Geological & Geophysical Surveys estimated that the field held of oil and of natural gas. Production did not begin until June 20, 1977 when the Alaska Pipeline
The Trans-Alaska Pipeline System (TAPS) is an oil transportation system spanning Alaska, including the trans-Alaska crude-oil pipeline, 11 pump stations, several hundred miles of feeder pipelines, and the Valdez Marine Terminal. TAPS is one of ...
was completed.
The site of the field's discovery was listed on the National Register of Historic Places
The National Register of Historic Places (NRHP) is the United States federal government's official list of districts, sites, buildings, structures and objects deemed worthy of preservation for their historical significance or "great artistic v ...
in 2000, and has a commemorative marker. A well was operated at that site until 1985.
Operations
The field was initially operated as two separate developments, the BP Western Operating Area (WOA: Oil Rim) and the ARCO Eastern Operating Area (EOA: Gas Cap). Upon acquisition of ARCO by BP and sale of ARCO Alaska assets to Phillips Petroleum in 2000, the two operating areas were consolidated and BP became the sole operator of the field.[
In the field, oil is moved through pipelines from about 1000 wells to a pumping station at the head of the Trans-Alaska Pipeline; "flow lines" carry oil from the wells to local processing centers, then through "transit lines" to the pumping station.][ According to a 2007 recording of BP representative, to replace the "huge volume of material" BP removes from beneath the ground, sea water is injected that is collected from ]Prudhoe Bay, Alaska
Prudhoe Bay is a census-designated place (CDP) located in North Slope Borough in the U.S. state of Alaska. As of the 2010 census, the population of the CDP was 2,174 people, up from just five residents in the 2000 census; however, at any give ...
.
Production
North Slope oil production peaked in 1989 at (Greater Prudhoe Bay: , but had fallen to in 2005, while Greater Prudhoe averaged in December, 2006 and Prudhoe itself averaged . Total production from 1977 through 2005 was .
As of August 2006, BP estimated that of recoverable oil remain and can be recovered with current technology.
Hilcorp energy is the field operator at Prudhoe Bay and has engaged in an aggressive redevelopment of the aging field since taking over as operator in mid-2019 from BP.
Prudhoe Bay production was in February compared with barrels per day in January and barrels per day year-over-year in February, 2021.
Associated oil fields
The Milne Point oil field is west of Prudhoe Bay and the leased area, called the Milne Point Unit by the State of Alaska, includes the Kuparuk River Oil Pool,[Staff, Alaska Oil and Gas Conservation Commission.]
AOGCC Pool Statistics, Milne Point Unit, Kuparuk River Oil Pool
Sag River Oil Pool,[Staff, Alaska Oil and Gas Conservation Commission.]
and the Schrader Bluff Oil Pool.[Staff, Alaska Oil and Gas Conservation Commission.]
The source rock
In petroleum geology, source rock is rock which has generated hydrocarbons or which could generate hydrocarbons. Source rocks are one of the necessary elements of a working petroleum system. They are organic-rich sediments that may have been depos ...
for the Prudhoe Bay Oil Field and neighboring reserves is a potential source for tight oil
Tight oil (also known as shale oil, shale-hosted oil or light tight oil, abbreviated LTO) is light crude oil contained in unconventional petroleum-bearing formations of low permeability, often shale or tight sandstone.
Economic production from ...
and shale gas
Shale gas is an unconventional natural gas that is found trapped within shale formations. Since the 1990s a combination of horizontal drilling and hydraulic fracturing has made large volumes of shale gas more economical to produce, and some ...
. As of 2013 mineral rights to 500,000 acres overlying the North Slope oil shale had been leased by Great Bear Petroleum whose principal is the petroleum geologist Ed Duncan.
Geology
The field is an anticline
In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex up in which the hinge or crest is the ...
structure located on the Barrow Arch, with faulting
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...
on the north side of the arch and a Lower Cretaceous
Lower may refer to:
*Lower (surname)
*Lower Township, New Jersey
*Lower Receiver (firearms)
*Lower Wick
Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is situated about five miles south west of Dursley, eig ...
unconformity
An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval o ...
on the east.
Claims on petroleum seep
A petroleum seep is a place where natural liquid or gaseous hydrocarbons escape to the earth's atmosphere and surface, normally under low pressure or flow. Seeps generally occur above either terrestrial or offshore petroleum accumulation stru ...
s in the Cape Simpson area were first made in 1915 by a group consisting of T.L. Richardson, W.B. Van Valen, O. Hansen, B. Panigeo and Egowa after these last two, Eskimos, pointed out two large mounds fifty feet high and 200 feet in diameter. Gold
Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...
prospectors Smith and Berry also discovered these seeps and formed an investment group in San Francisco led by R.D. Adams, who funded an investigation led by the geologist H.A. Campbell. His report noted disputing claims by Standard Oil Company
Standard Oil Company, Inc., was an American oil production, transportation, refining, and marketing company that operated from 1870 to 1911. At its height, Standard Oil was the largest petroleum company in the world, and its success made its co-f ...
. This led to the establishment of the Naval Petroleum Reserve No. 4
A navy, naval force, or maritime force is the branch of a nation's armed forces principally designated for naval and amphibious warfare; namely, lake-borne, riverine, littoral, or ocean-borne combat operations and related functions. It inc ...
in 1923, after which the Navy engaged the United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...
to survey the area from 1923 until 1926, who concluded the best objectives were Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
rocks. From 1943 until 1953, the Navy drilled eighty wells, including the area at Cape Simpson and Umiat
Umiat (OO-mee-yat) is an unincorporated community in North Slope Borough, Alaska, United States. It is located on the Colville River, 140 miles southwest of Deadhorse in the Arctic Circle. The town is not accessible by road or rail, only by ai ...
but none flowed more than 250 barrels per day.
The discovery of the Swanson River Oil Field on the Kenai Peninsula
The Kenai Peninsula ( Dena'ina: ''Yaghenen'') is a large peninsula jutting from the coast of Southcentral Alaska. The name Kenai (, ) is derived from the word "Kenaitze" or "Kenaitze Indian Tribe", the name of the Native Athabascan Alaskan trib ...
in 1957 by the Richfield Oil Corporation
Richfield Oil Corporation was an American petroleum company based in California from 1905 to 1966. In 1966 it merged with Atlantic Refining Company to form the Atlantic Richfield Company (later renamed ARCO).
History
The Richfield Oil Corporat ...
prompted the company to send geologists to the Arctic starting in 1959 and seismic survey crews in 1963, which recorded a reconnaissance line across what was identified as the Prudhoe structure in 1964. In 1965, during the state lease sale, Richfield partnered with Humble Oil
Humble Oil and Refining Co. is a defunct American oil company founded in 1911 in Humble, Texas. In 1919, a 50% interest in Humble was acquired by the Standard Oil of New Jersey which acquired the rest of the company in September 1959. The Humbl ...
and acquired leases over what was later identified as the gas cap while British Petroleum was awarded leases over the "oil ring".
In 1968, Prudhoe Bay State No. 1 encountered the Permian
The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...
-Triassic
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...
Sadlerochit formation at 8200 feet which flowed gas at 1.25 million cubic feet per day with 20–27 per cent porosity
Porosity or void fraction is a measure of the void (i.e. "empty") spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0% and 100%. Strictly speaking, some tests measure ...
and "tens of millidarcies" permeability. Oil, condensate and gas are produced from the Triassic, Ivishak sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks.
Most sandstone is composed of quartz or feldspar (both silicates) ...
. This reservoir was deposited as a complex amalgamation of fan deltas and alluvial fans. The continuity of this fan delta was shown to extend seven miles away when the ARCO-Humble Sag River State No. 1 well was drilled. During the field's early life the oil-bearing sandstone in some locations was thick. Today, the oil bearing zone's average thickness is about and the initial estimate of Oil in place
Oil in place (OIP) (not to be confused with original oil-in-place (OOIP)) is a specialist term in petroleum geology that refers to the total oil content of an oil reservoir. As this quantity cannot be measured directly, it has to be estimated fr ...
was 2.3 billion barrels.
The original target of the Prudhoe Bay State No. 1 was the Mississippian Lisburne limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...
, encountered at 8,800 feet and flowed 1,152 barrels of oil per day in the 9,505 to 9,825 foot interval along with 1.3 million cubic feet of gas. This initial oil was burned "because there wasn't ample storage", the flames of which were spotted by a passing airline. The Department of Energy in 1991 estimated oil in place for this formation at 3.1 billion barrels.
Statistics
Statistics for the Greater Prudhoe Bay Field:
* Discovery well: Prudhoe Bay State #1
* Discovery date: December 26, 1967["The Prize" Daniel Yergin]
* Step-out well March 1968 confirmed
* Production start: June 20, 1977
* Total field area:
* Oil production wells: 1114
* Total capacity:
** Produced: as of March 28, 2013
** Total recoverable:
** Remaining recoverable:
* Peak production: 1.97 million barrels per day (1988)
* Natural gas:
** Total: (estimated)
** Recoverable:
* Greater Prudhoe Bay satellite fields:
** East Operating Area (formerly ARCO)(production start date: 1977)
** West Operating Area (BP Exploration)(production start date: 1977)
** Midnight Sun (production start date: 1998)
** Aurora (production start date: 2000)
** Orion (production start date: 2002)
** Polaris (production start date: 1999)
** Borealis (production start date: 2001)
* Ownership:
** BP Exploration (Operator): 26%
** ConocoPhillips.: 36%
** ExxonMobil: 36%
** Others: 2%
*On 27 August 2019 BP announces the agreement to sell all its Alaska operations and interests to Hilcorp for $5.6 billion. The transaction includes interests in giant Prudhoe Bay field and Trans Alaska Pipeline.
March 2006 oil spill
On March 2, 2006, a worker for BP Exploration (Alaska) discovered an oil spill in western Prudhoe Bay. Up to were spilled, making it the largest oil spill on Alaska's north slope to date. The spill was attributed to a pipeline rupture.
In October 2007, BP was found guilty to a misdemeanor violation of the Clean Water Act to resolve criminal liability relating to pipeline leaks of crude oil. As a result of the guilty plea, BP Alaska agreed to pay $20 million which included the criminal fine, community service payments and criminal restitution.
August 2006 shutdown
The March 2006 oil spill led the United States Department of Transportation
The United States Department of Transportation (USDOT or DOT) is one of the executive departments of the U.S. federal government. It is headed by the secretary of transportation, who reports directly to the President of the United States and ...
to mandate that the transit lines be inspected for corrosion. As a result, BP announced on 6 August 2006 they had discovered severe corrosion, with losses of 70 to 81 percent in the 3/8-inch thickness of the pipe walls. Oil leaking was reported in one area, with the equivalent of four to five barrels of oil spilled. The damage required replacement of 16 of of pipeline at the Prudhoe Bay. BP said it was surprised to find such severe corrosion and that it had been 14 years since they had used a pipeline inspection gauge
In pipeline transportation, pigging is the practice of using pipeline inspection gauges or gadgets, devices generally referred to as pigs or scrapers, to perform various maintenance operations. This is done without stopping the flow of the pr ...
("pig") to clean out its lines because the company believed the use of the pigging equipment might damage pipe integrity.[ ] BP Exploration announced that they were shutting down the oil field indefinitely, due to the severe corrosion and a minor leak in the oil transit lines. This led to an 8% reduction in the amount of oil produced by the United States, as Prudhoe Bay was the country's largest oil producer, producing over .
BP initially estimated up to 2 to 3 months before the pipelines would be fully operational. This caused increases in world oil prices, and BP revised the estimated operational date to January 2007. London brent crude
Brent Crude may refer to any or all of the components of the Brent Complex, a physically and financially traded oil market based around the North Sea of Northwest Europe; colloquially, Brent Crude usually refers to the price of the ICE (Intercon ...
hit an intra-day high of $77.73/barrel, the all-time high, at that time, being $78.18/barrel. United States crude oil
Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crude ...
peaked at $76.67/barrel. The state of Alaska, which gets most of its revenue from taxing the oil industry, lost as much as $6.4 million each day until production restarted.
No part of the Alaska Pipeline
The Trans-Alaska Pipeline System (TAPS) is an oil transportation system spanning Alaska, including the trans-Alaska crude-oil pipeline, 11 pump stations, several hundred miles of feeder pipelines, and the Valdez Marine Terminal. TAPS is one of ...
was affected, although Alyeska said that lower crude oil volumes could slow pumping during the BP shutdown.
The field has since reopened. In mid-June 2007, however, a small leak occurred in one of the pipelines that connect the field to the Trans-Alaska Pipeline
The Trans-Alaska Pipeline System (TAPS) is an oil transportation system spanning Alaska, including the trans-Alaska crude-oil pipeline, 11 pump stations, several hundred miles of feeder pipelines, and the Valdez Marine Terminal. TAPS is one o ...
, shutting down the field for a week.
In March 2009 the State of Alaska sued BP in matter number 3AN-09-06181-CI alleging that BP was negligent in its management of rigging operations and corrosion control in the transit lines leading from the field into pumping station one of the Trans Alaska Pipeline. The state is seeking damages for lost royalty and tax revenues. The case seems to have been dismissed in 2010.
See also
* Mount Elbert Gas Hydrate Site
References
Further reading
* Jamison, H.C., Brockett, L.D., and McIntosh, R.A., 1980, Prudhoe Bay – A 10-Year Perspective, in Giant Oil and Gas Fields of the Decade: 1968–1978, AAPG Memoir 30, Tulsa: American Association of Petroleum Geologists, .
*
External links
Oil and Gas Resources of the Arctic Alaska Petroleum Province
NPRA
Milne Point goes mainstream. Inc. oilfield
('' Alaska Business Monthly'', April 1995.)
Prudhoe Bay, Alaska
Aerial photos from the Prudhoe Bay area, July 2010
{{Petroleum industry
1968 establishments in Alaska
ARCO
BP oil and gas fields
ConocoPhillips oil and gas fields
ExxonMobil oil and gas fields
Geography of North Slope Borough, Alaska
Industry in the Arctic
Oil fields in Alaska