Prudhoe Bay Oil Field is a large oil field on Alaska's North Slope. It is the largest oil field in North America, covering and originally contained approximately of oil.Prudhoe Bay Fact Sheet . 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), while the largest by reserves is the Permian Basin (North America). The field was operated by BP; partners were ExxonMobil and ConocoPhillips until August 2019; when BP sold all its Alaska assets to Hilcorp.

Location The field is located north of Fairbanks and north of Anchorage, north of the Arctic Circle, and south of the North Pole. It is on the North Slope and lies between the National Petroleum Reserve–Alaska to the west and the Arctic National Wildlife Refuge to the east. It is accessible by road from Fairbanks, Alaska via the Elliott Highway and Dalton Highway.

Leasing

The State of Alaska owns the land and leases the area as the Prudhoe Bay Unit.Staff, Alaska Oil and Gas Conservation Commission. 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.

Pool name Operator Discovery well driller Discovery well start date AuroraStaff, Alaska Oil and Gas Conservation Commission. AOGCC Pool Statistics, Prudhoe Bay Unit, Aurora Oil Pool BP Exploration Mobil August 24, 1969 Borealis PoolStaff, Alaska Oil and Gas Conservation Commission. AOGCC Pool Statistics, Prudhoe Bay Unit, Borealis Oil Pool BP Exploration Mobil August 8, 1969 LisburneStaff, Alaska Oil and Gas Conservation Commission. AOGCC Pool Statistics, Prudhoe Bay Unit, Lisburne Oil Pool BP Exploration Arco December 16, 1967 Midnight SunStaff, Alaska Oil and Gas Conservation Commission. AOGCC Pool Statistics, Prudhoe Bay Unit, Midnight Sun Oil Pool BP Exploration BP Exploration December 20, 1997 Russell Drilling UndefStaff, Alaska Oil and Gas Conservation Commission. AOGCC Pool Statistics, Prudhoe Bay Unit, Niakuk Ivsh-SR Undef Oil Pool BP Exploration BP Exploration March 10, 2001 NiakukStaff, Alaska Oil and Gas Conservation Commission. AOGCC Pool Statistics, Prudhoe Bay Unit, Niakuk Oil Pool BP Exploration Sohio April 18, 1985 N Prudhoe BayStaff, Alaska Oil and Gas Conservation Commission. AOGCC Pool Statistics, Prudhoe Bay Unit, N Prudhoe Bay Oil Pool BP Exploration Arco April 4, 1970 OrionStaff, Alaska Oil and Gas Conservation Commission. AOGCC Pool Statistics, Prudhoe Bay Unit, Orion Oil Pool BP Exploration Mobil April 7, 1969 PolarisStaff, Alaska Oil and Gas Conservation Commission. AOGCC Pool Statistics, Prudhoe Bay Unit, Polaris Oil Pool BP Exploration BP Exploration August 24, 1969 Pt. McIntyreStaff, Alaska Oil and Gas Conservation Commission. AOGCC Pool Statistics, Prudhoe Bay Unit, Pt. McIntyre Oil Pool BP Exploration Arco / Exxon March 22, 1988 PrudhoeStaff, Alaska Oil and Gas Conservation Commission. AOGCC Pool Statistics, Prudhoe Bay Unit, Prudhoe Oil Pool BP Exploration Arco December 19, 1967 PM Stump IslandStaff, Alaska Oil and Gas Conservation Commission. AOGCC Pool Statistics, Prudhoe Bay Unit, PM Stump Island BP Exploration Arco / Exxon March 22, 1988 PM UndefinedStaff, Alaska Oil and Gas Conservation Commission. AOGCC Pool Statistics, Prudhoe Bay Unit, PM Undefined BP Exploration BP Exploration January 25, 1997 Ugnu Undefined WTRSPStaff, Alaska Oil and Gas Conservation Commission. AOGCC Pool Statistics, Prudhoe Bay Unit, Ugnu Undefined WTRSP BP Exploration BP Exploration May 20, 2004 West BeachStaff, Alaska Oil and Gas Conservation Commission. Pool Statistics, Prudhoe Bay Unit, West Beach Oil Pool BP Exploration Arco July 26, 1976 W Beach Tertiary Undef WTR PoolStaff, Alaska Oil and Gas Conservation Commission. Pool Statistics, Prudhoe Bay Unit, W Beach Tertiary Undef WTR Pooll BP Exploration Arco / Exxon July 22, 1976

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 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 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 (which later became part of Exxon) and Atlantic Richfield Company (ARCO), with the well Prudhoe Bay State #1.Arthur C. Banet, Jr. U.S Department of the Interior, Bureau of Land Management Alaska State Office. March 1991. Oil and Gas Development on Alaska's North Slope: Past Results and Future Prospects. BLM-Alaska Open File Report 31. ARCO was the operating partner.Steve Quinn for Petroleum News. Vol. 16, No. 14 Week of April 03, 2011 ExxonMobil in Alaska: Exxon selects Prudhoe discovery well site: Humble Oil assumed an unusually active role as Atlantic Richfield’s 50-50 partner on Alaska’s North Slope in the 1960s Drilling sites for the discovery and confirmation wells were staked by geologist Marvin Mangus. 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.Estimated Speculative Recoverable Resources of Oil and Natural Gas in Alaska . Division of Geological & Geophysical Surveys. Department of Natural Resources. State of Alaska. January 1974. (Adobe Acrobat *.PDF document) Production did not begin until June 20, 1977 when the Alaska Pipeline was completed.

The site of the field's discovery was listed on the National Register of Historic Places 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 the acquisition of ARCO by BP and the 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 a BP representative, to replace the "huge volume of material" BP removes from beneath the ground, seawater is injected that is collected from Prudhoe Bay.

Production North Slope oil production peaked in 1988 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. BP Plans to Pull Another 2B Barrels of Oil from Alaska's Prudhoe Bay. Rigzone. February 22, 2008.

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. AOGCC Pool Statistics, Milne Point Unit, Sag River Oil Pool and the Schrader Bluff Oil Pool.Staff, Alaska Oil and Gas Conservation Commission. AOGCC Pool Statistics, Milne Point Unit, Schrader Bluff Oil Pool

The source rock for the Prudhoe Bay Oil Field and neighboring reserves is a potential source for tight oil and shale gas. 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. Paul Basinski, who has been called "one of the fathers of fracking", drove the exploration of fracking of the highly radioactive zone shale (HRZ shale) at Prudhoe Bay Oil Field; he died in 2018 of complications following a heart transplant.

Geology

The field is an anticline structure located on the Barrow Arch, with faulting on the north side of the arch and a Lower Cretaceous unconformity on the east.Sweet, J.M., 2008, Discovery at Prudhoe Bay Oil, Blaine: Hancock House, , p. 183

Claims on petroleum seeps 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.Sweet, J.M., 2008, Discovery at Prudhoe Bay Oil, Blaine: Hancock House, , p. 63 Gold 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.Sweet, J.M., 2008, Discovery at Prudhoe Bay Oil, Blaine: Hancock House, , pp. 64–65 His report noted disputing claims by Standard Oil Company.Sweet, J.M., 2008, Discovery at Prudhoe Bay Oil, Blaine: Hancock House, , p. 65 This led to the establishment of the Naval Petroleum Reserve No. 4 in 1923, after which the Navy engaged the United States Geological Survey to survey the area from 1923 until 1926, who concluded the best objectives were Cretaceous rocks.Sweet, J.M., 2008, Discovery at Prudhoe Bay Oil, Blaine: Hancock House, , pp. 68 and 86 From 1943 until 1953, the Navy drilled eighty wells, including the area at Cape Simpson and Umiat but none flowed more than 250 barrels per day.Sweet, J.M., 2008, Discovery at Prudhoe Bay Oil, Blaine: Hancock House, , pp. 94–95

The discovery of the Swanson River Oil Field on the Kenai Peninsula in 1957 by the Richfield Oil Corporation 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.Sweet, J.M., 2008, Discovery at Prudhoe Bay Oil, Blaine: Hancock House, , pp. 111, 129 and 133 In 1965, during the state lease sale, Richfield partnered with Humble Oil and acquired leases over what was later identified as the gas cap while BP was awarded leases over the "oil ring".Sweet, J.M., 2008, Discovery at Prudhoe Bay Oil, Blaine: Hancock House, , p. 170