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.

[21][22] 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.

[1][25]: slide 4  In 1974 the State of 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.

[1] The site of the field's discovery was listed on the National Register of Historic Places in 2000, and has a commemorative marker.

[25]: slide 4 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.

As of August 2006, BP estimated that 2 billion barrels (320×10^6 m3) of recoverable oil remain and can be recovered with current technology.

[40] Gold prospectors Smith and Berry also discovered these seeps and formed an investment group in San Francisco led by R.D.

[43] 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.

[44] 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.

The continuity of this fan delta was shown to extend seven miles away when the ARCO-Humble Sag River State No.

[51] This initial oil was burned "because there wasn't ample storage", the flames of which were spotted by a passing airline.

In October 2007, BP was found guilty of a misdemeanor violation of the Clean Water Act to resolve criminal liability relating to pipeline leaks of crude oil.

[58] 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 thickness of the pipe walls.

[60] This caused increases in world oil prices,[62] and BP revised the estimated operational date to January 2007.

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.

[64] No part of the Alaska Pipeline was affected, although Alyeska said that lower crude oil volumes could slow pumping during the BP shutdown.