Production from the Prudhoe Bay field, which contains the largest single accumulation of oil ever discovered in North America, is expected to commence in 1977. Recent approval of the construction of an oil pipeline from Prudhoe Bay to Valdez has resulted in a marked increase in both drilling and construction activity in the field area. Already over 100 wells have been drilled as a result of almost 7 years of operation, and considerable subsurface data on the Permo-Triassic formations are now available. On the basis of these data, this paper describes geological and petro-physical aspects of the main Prudhoe Bay reservoirs.

Three reservoirs are contained within the Permo-Triassic. These are, in descending order, the Sag River Formation, the Shublik Formation, and the Ivishak Sandstone. The Ivishak Sandstone reservoir of the Sadlerochit Group contains most of the field's hydrocarbons.

Observations of the distribution of gas, oil, and water in the field have led to hypotheses regarding the origin and distribution of the hydrocarbons.