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.
The region contains 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. Under the North Slope is an ancient seabed – the source of the oil. Within the North Slope, there is 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 Barrow to a point just west of the Arctic National Wildlife Refuge. 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.
The source rock for the Prudhoe Bay Oil Field and neighboring reserves is also a potential source for tight oil and shale gas – it could contain "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."