|Alaska State: 400 miles north of Fairbanks, 650 miles north of Anchorage, 250 miles north of the Arctic Circle, 1200 miles from the North Pole - US
|Prudhoe Bay oil field is a large oil field covering an area of 213,543 acres (864.18 km2) and containing approximately 25 billion barrels (4.0 × 109 m3) of oil from 1114 production wells.
The main reservoir in the Field is the 450-foot thick Permo-Triassic Ivishak formation, with the much thinner Sag River formation forming a second reservoir above the Ivishak. The rock formations have been bent into a broad arch, with a discontinuity called the lower Cretaceous unconformity cutting out the crest of the arch.
Oil and gas in the reservoir rock became trapped in the Sadlerochit formation, which is a gravel and sandstone structure nearly 9,000 feet (2,700 m) under the surface, against the unconformity to form the oilfield.
BP drilled 62 new wells in the field in 2009. Those wells primarily involved sidetracking, a technique involving the drilling of a new well bore out from the side of an existing, poorly performing well BP anticipates.
|The field was discovered with the well Prudhoe Bay State #1.
|Alaska's Division of Geological & Geophysical Surveys estimated that the field held 10 billion barrels (1.6×109 m3) of oil and 26 trillion cubic feet (740×10^9 m3) of natural gas.
|Production began on the field as Alaska Pipeline was completed.
|Sohio, which was an American oil company that was acquired by British Petroleum, now called BP, drilled A-22 as a producing well.
The Well design includes 20” conductor casing, 13-3/8” surface casing, 9-5/8” production casing, 7” production liner, and 3-1/2” production tubing. Surface and production casing strings were successfully tested to 3,000 PSI at installation. The well is configured for artificial lift, provided by inecting gas down the IA under controlled conditions.
|A non-rig Coiled Tubing Unit (CTU) cement squeeze technique was developed and proven in the Prudhoe Bay field. This new technique does not require that the well be killed.
|The first CT packer repair was completed, using a rig workover to pull tubing and replace the first failed packer in 1978.
|The production of the field reached to 2 million barrels per day (320×10^3 m3/d).
|Gas lift of A-22 was suspended as reservoir pressure had increased due to pressure support from the ongoing enhanced oil recovery (EOR), allowing the well to produce without gas lift.
|The Trans-Alaska Pipeline System (TAPS) shut down resulted in the shut in of A-22. Efforts to freeze protect A-22 for a short duration shut in included pressuring up the tubing with lift gas.
|A rapid release of gas from below the pad surface of A-22 led to an explosion and fire that was for five hours.
|Well A-22 was restarted following repairs to surface production equipment.
|The Prudhoe Bay field was undergoing EOR. Alternating volumes of water and enriched gas are injected via selected wells into the reservoir to raise pressure and sweep the producing zone of residual oil, increasing ultimate recovery.
|The production had fallen to 943,000 barrels per day (149,900 m3/d).
|A large oil spill has been discovered in western Prudhoe Bay. Up to one million litres (267,000 gallons) of crude were spilled from a corroded transit pipeline at the state's northern tip.
|BP had discovered severe corrosion, with losses of 70 to 81 percent in the 3/8-inch of the wall thickness of the pipe.
Because of BP's quick response and containment of oil leak, as well as the company's cooperation with the government investigation, no criminal charge was lodged against BP for the second spill.
|BP Exploration Alaska, Inc. has begun an orderly and phased shutdown of the Prudhoe Bay oil field following the discovery of unexpectedly severe corrosion and a small spill from a Prudhoe Bay oil transit line.
|The oil production at Prudhoe Bay field was still shut and BP had restored most of it.
|Another oil spill emanated from the Prudhoe Bay pipeline and covered nearly five acres of frozen tundra. The company closed down 245 wells that resulted in a 100,000 barrel per day decrease in oil production.
|Exxon Mobil Corporation
|BP Plc is the operator of the Prudhoe Bay Field.
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