Alaska North Slope

North Slope Borough, Alaska Juneau, Alaska List of boroughs and census areas in Alaska
A map of northern Alaska; the dotted line shows the southern boundary of the North Slope. The National Petroleum Reserve -Alaska is to the West, the Arctic National Wildlife Refuge to the east, and Prudhoe Bay is between them.

The Alaska North Slope is the region of the U.S. state of Alaska located on the northern slope of the Brooks Range along the coast of two marginal seas of the Arctic Ocean, the Chukchi Sea being on the western side of Point Barrow, and the Beaufort Sea on the eastern.

Petroleum resources

Map from the US Bureau of Land Management showing structures that create the oil fields in Alaska
Geophysical Service Inc. seismic exploration crew, Deadhorse, Alaska, 1981

The Alaska North Slope region includes the National Petroleum Reserve–Alaska, with the bulk of Alaska's known petroleum until the Prudhoe Bay Oil Field was discovered in 1968, followed by the Kuparuk River oil field in 1969. The region also includes the Arctic National Wildlife Refuge, which itself has been the subject of controversy surrounding the possibility of petroleum drilling within its boundaries. The petroleum extracted from the region is transferred south by means of the Trans-Alaska Pipeline System to Valdez on the Pacific Ocean.[1] Under the North Slope is an ancient seabed, which is the source of the oil. Within the North Slope, there is a geological feature called the Barrow Arch – a belt of the kind of rock known to be able to serve as a trap for oil. It runs from the city of Utqiagvik to a point just west of the Arctic National Wildlife Refuge.[1][2] The Arctic Alaska Petroleum Province, encompassing all the lands and adjacent Continental Shelf areas north of the Brooks Range-Herald arch (see map) were estimated by the USGS in 2005 to hold more than 50 billion bbl of oil and natural-gas liquids and 227 trillion cubic feet of gas.[2]

The source rock for the Prudhoe Bay Oil Field and neighboring reserves is also a potential source for tight oil and shale gas – possibly containing "up to 2 billion barrels of technically recoverable oil and up to 80 trillion cubic feet of natural gas, according to a 2012 U.S. Geological Survey report."[3]

Ira Harkey quotes Noel Wien as stating that in the 1920s, "To keep warm and to cook with, the Eskimo was burning hunks of dark stuff he just picked up on the ground all around his tent. This was oil from seepage under the tundra. The Eskimos had always known about the oil, long before there was any drilling for it."[4]

Alaska North Slope (ANS) crude production

Alaska North Slope (ANS) is a more expensive waterborne crude.[5] Since 1987, Alaska North Slope (ANS) crude production has been in decline.[6]


Landsat 7 false-color image of the North Slope. Along the coast, fast ice still clings to the shore in a solid, frozen sheet. At the top of the scene is the drifting sea ice. A dark blue strip of open water, known as a flaw lead, separates the fast ice from the drifting sea ice. The Brooks Range is visible at the bottom. (June 2001)

Within the North Slope, only a surface "active layer" of the tundra thaws each season; most of the soil is permanently frozen year-round. On top of this permafrost, water flows to sea via shallow, braided streams or settles into pools and ponds.[1] Along the bottom of the Landsat 7 image on the right, the rugged terrain of the Brooks Range mountains is snow-covered in places (blue areas) and exposed (pink areas) in others.

Much of the region is located in North Slope Borough.

On August 12, 2018, a 6.3 magnitude earthquake hit the region, the most powerful recorded for the Alaskan North Slope.[7]

See also


  1. ^ a b c Canby, Peter (November 17, 2005). "The Specter Haunting Alaska". New York Review of Books. Archived from the original on 2005-10-31.
  2. ^ a b Houseknecht, David W.; Bird, Kenneth J. "Studies by the U.S. Geological Survey in Alaska, 2005" (PDF). Professional Paper 1732–A Oil and Gas Resources of the Arctic Alaska Petroleum Province
  3. ^ Margaret Kriz Hobson (April 3, 2013). "SHALE OIL: Geologist's Alaska gamble could turn into America's next big shale play". EnergyWire, E & E Publishing. Retrieved April 4, 2013.
  4. ^ Harkey, Ira (1991). Pioneer Bush Pilot. Bantam Books. p. 239–240. ISBN 0553289195.
  5. ^ Auers, John R.; Mayes, John (5 June 2013), "North American production boom pushes crude blending", Oil & Gas Journal, Dallas, Texas, 111 (5), retrieved December 28, 2013
  6. ^ Fielden, Sandy (February 1, 2013), After the Oil Rush – ANS Decline and the West Coast Crude Market, RBN Energy, retrieved 27 December 2013
  7. ^ Missing or empty |title= (help)