The Umiat oil field is in Naval Petroleum Reserve No. 4 between the Brooks Range and Arctic Ocean in far northern Alaska. The Umiat anticline has been tested by 11 wells, six of which produced oil: however, the productive capacity and recoverable reserves of the field are subjects to considerable speculation because of unusual reservoir conditions and because several wells appear to have seriously damaged during drilling and completion. Oil is produced at depths of 273 to 1,100 feet: the depth to the bottom of the permanently frozen zone varies form about 800 to 1,100 feet, so that most of the oil reserves are in the permafrost. Reservoir pressures are estimated to range from 50 to 350 psi, increasing with depth and the small amount of gas dissolved in the oil is the major source of energy for production. Laboratory tests were made on cores under simulated permafrost conditions to estimate oil recoverable by solution gas expansion from low saturation pressures. The cores were also tested for clay content and susceptibility to productivity impairment by swelling clays and increased water content if exposed to fresh water. The results indicate that oil can be produced from reservoir rocks in the permafrost and that substantial amounts of oil can be produced from depletion-drive reservoirs by a pressure drop of as little as 100psi below the saturation pressure. Freezing of formation water reduces oil productivity much more than that due to increased oil viscosity. Failure of wells drilled with water-base mud to produce is attributed to freezing of water in the area immediately surrounding the wellbore. Swelling clays apparently contributed very little to the plugging of the wells.