Prudhoe Bay Oil Field

Prudhoe Bay oil field
Location of Prudhoe Bay oil field
Country	United States
Region	Alaska North Slope
Offshore/onshore	onshore
Coordinates	70°18′24″N 148°43′57″W{{#coordinates:70|18|24|N|148|43|57|W|type:landmark |primary |name= }}
Operator(s)	BP
Partners	BP, ExxonMobil, ConocoPhillips Alaska
Field history
Discovery	March 12, 1968 by ARCO and Exxon's Prudhoe Bay State #1 well
Start of production	June 20, 1977
Peak of production	1.5 million barrels per day (Bad rounding here{{#invoke:Math|precision_format| 238,480.942392 | 1-5 }} m3/d)
Peak year	1979
Production
Current production of oil	660,000 barrels per day (~×10^ t/a)
Year of current production of oil	2010
Estimated oil in place	25,000 million barrels (~×10^ t)
Estimated gas in place	26,000 billion cubic feet (Bad rounding here{{#invoke:Math|precision_format| 26,000*28,316,846.592/1,000,000,000 | 1-2 }}×10^9 m3)
Producing formations	Sadlerochit

Caribou near Prudhoe Bay, 1973

Prudhoe Bay oil field is a large oil field on Alaska's North Slope. It is the largest oil field in both the United States and in North America, covering 213,543 acres (Bad rounding here{{#invoke:Math|precision_format| 86,417.7860923 | 1-4 }} ha) and originally containing approximately 25 billion barrels (Bad rounding here{{#invoke:Math|precision_format| 3,974,682,373.2 | 1-9 }} m³) of oil. The amount of recoverable oil in the field is more than double that of the next largest field in the United States, the East Texas oil field. The field is operated by BP; partners are ExxonMobil and ConocoPhillips Alaska.

Location

The field is located 400 miles (Bad rounding here{{#invoke:Math|precision_format| 643.7376 | 1-2 }} km) north of Fairbanks and 650 miles (Bad rounding here{{#invoke:Math|precision_format| 1,046.0736 | 1-3 }} km) north of Anchorage, 250 miles (Bad rounding here{{#invoke:Math|precision_format| 402.336 | 1-2 }} km) north of the Arctic Circle, and 1,200 miles (Bad rounding here{{#invoke:Math|precision_format| 1,931.2128 | 1-3 }} km) from the North Pole.

History

Commercial oil exploration started in Prudhoe Bay area in the 1960s and the field was discovered on March 12, 1968, by Atlantic Richfield Company (ARCO) and Exxon, with the well Prudhoe Bay State #1. Drilling sites for the discovery and confirmation wells were staked by geologist Marvin Mangus. In 1974 the State of Alaska's Division of Geological & Geophysical Surveys estimated that the field held 10 billion barrels (Bad rounding here{{#invoke:Math|precision_format| 1,589,872,949.28 | 1-9 }} m³) of oil and 26 trillion cubic feet (Bad rounding here{{#invoke:Math|precision_format| 26*28,316,846,592/1,000,000,000 | 1-2 }}×10^⁹ m³) of natural gas. Production did not begin until June 20, 1977 when the Alaska Pipeline was completed. 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).

Cumulative North Slope oil peaked in 1989 at 2 million barrels per day (Bad rounding here{{#invoke:Math|precision_format| (2)*(5.520392185/3)/(5/432) | 1-2 }}×10^³ m³/d) (Greater Prudhoe Bay: 1.5 million barrels per day (Bad rounding here{{#invoke:Math|precision_format| (1.5)*(5.520392185/3)/(5/432) | 1-2 }}×10^³ m³/d), but had fallen to 943,000 barrels per day (Bad rounding here{{#invoke:Math|precision_format| 149,925.019117 | 1-5 }} m³/d) in 2005, while Greater Prudhoe averaged 411,000 barrels per day (Bad rounding here{{#invoke:Math|precision_format| 65,343.7782154 | 1-4 }} m³/d) in December, 2006 and Prudhoe itself averaged 285,000 barrels per day (Bad rounding here{{#invoke:Math|precision_format| 45,311.3790545 | 1-4 }} m³/d). Total production from 1977 through 2005 was 11 billion barrels (Bad rounding here{{#invoke:Math|precision_format| (11)*158,987,294.928/1,000,000,000 | 1-0 }}×10^⁹ m³).

As of August 2006, BP estimated that 2 billion barrels (Bad rounding here{{#invoke:Math|precision_format| (2)*158,987,294.928/1,000,000 | 1-2 }}×10^⁶ m³) of recoverable oil remain and can be recovered with current technology.

Associated oil fields

The Milne Point oil field is 35 miles (Bad rounding here{{#invoke:Math|precision_format| 56.32704 | 1-1 }} km) west of Prudhoe Bay.

Geology

Oil, condensate and gas are produced from the Triassic, Ivishak sandstone. This reservoir was deposited as a complex amalgamation of fan deltas and alluvial fans. The oil is trapped in the Sadlerochit formation, a gravel and sandstone structure nearly 9,000 feet (Bad rounding here{{#invoke:Math|precision_format| 2,743.2 | 1-3 }} m) under the surface. During the field’s early life the oilbearing sandstone in some locations was 600 feet (Bad rounding here{{#invoke:Math|precision_format| 182.88 | 1-2 }} m) thick. Today, the oil bearing zone's average thickness is about 60 feet (Bad rounding here{{#invoke:Math|precision_format| 18.288 | 1-1 }} m).

Stats

Statistics for the Greater Prudhoe Bay Field:

• Discovery well: Prudhoe Bay State #1
• Discovery date: March 12, 1968
• Production start: June 20, 1977
• Total field area: 213,543 acres (Bad rounding here{{#invoke:Math|precision_format| 864.177860923 | 1-2 }} km²)
• Oil production wells: 1114
• Total capacity: 25 billion barrels (Bad rounding here{{#invoke:Math|precision_format| 3,974,682,373.2 | 1-9 }} m³)
  • Produced: 11 billion barrels (Bad rounding here{{#invoke:Math|precision_format| 1,748,860,244.21 | 1-9 }} m³)
  • Total recoverable: 13 billion barrels (Bad rounding here{{#invoke:Math|precision_format| 2,066,834,834.06 | 1-9 }} m³)
  • Remaining recoverable: 2 billion barrels (Bad rounding here{{#invoke:Math|precision_format| 317,974,589.856 | 1-8 }} m³)
• Peak production: 1.5 million barrels per day (Bad rounding here{{#invoke:Math|precision_format| 238,480.942392 | 1-5 }} m³/d) (1979)
• Natural gas:
  • Total: 46×10^¹² cu ft (Bad rounding here{{#invoke:Math|precision_format| 1,302.57494323 | 1-3 }} km³) (estimated)
  • Recoverable: 26×10^¹² cu ft (Bad rounding here{{#invoke:Math|precision_format| 736.238011392 | 1-2 }} km³)
• 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 Alaska Inc.: 36%
  • ExxonMobil: 36%
  • Others: 2%

March 2006 oil spill

On March 2, 2006, a worker for BP Exploration (Alaska) discovered a large oil spill in western Prudhoe Bay. Up to 267,000 gallons were spilled, making it the largest oil spill on Alaska's north slope to date. The spill was attributed to a pipeline rupture.

According to King 5, BP paid a $20 million fine for the spill. On November 3, 2008, [[BP]] issued a response to [http://www.king5.com/business/stories/NW_110308ENV_epa_alaska_spill_folo_SW.1797aa4f2.html King 5] the report stating that they "had no record that any concerns about corrosion leading to an oil transit line breach in the foreseeable future ever were communicated to BP." ==August 2006 shutdown== The March 2006 oil spill led the [[United States Department of Transportation]] 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 of the wall thickness of the pipe. 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 22 miles ([[Category:Pages with bad rounding precision]]Bad rounding here{{#invoke:Math|precision_format| 35.405568 | 1-1 }} km) 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]] ("pig") to clean out its lines because the company believed the use of the rigging 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 of America]], as Prudhoe Bay is the country's largest oil producer, producing over 400,000 barrels per day ([[Category:Pages with bad rounding precision]]Bad rounding here{{#invoke:Math|precision_format| 63,594.9179712 | 1-4 }} m³/d). 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]] hit an intra-day high of $77.73/barrel, the all-time high, at that time, being $78.18/barrel. [[United States]] [[crude oil]] 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 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, 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 matter is still being disputed.

Further reading

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External links

• Milne Point goes mainstream. Inc. oilfield (Alaska Business Monthly, April, 1995.)
• Prudhoe Bay, Alaska Aerial photos from the Prudhoe Bay area, July 2010

de:Prudhoe-Bay-Ölfeld