The U.S. Geological Survey (USGS) estimates 896 million barrels of conventional, undiscovered oil and 53 trillion cubic feet of conventional, undiscovered non-associated gas within the National Petroleum Reserve in Alaska (NPRA) and adjacent state waters.  The estimated volume of undiscovered oil is significantly lower than in 2002, when the USGS estimated there was 10.6 billion barrels of oil. The new result, roughly 10 percent of the 2002 estimate, is due primarily to recent exploration drilling indicating gas occurrence rather than oil in much of NPRA.

Recent activity in NPRA, including 3-D seismic surveys, federal lease sales administered by the Bureau of Land Management, and drilling of more than 30 exploration wells in the area, provides geologic indicators that are more indicative of gas than oil.  Many of the newly drilled wells show an abrupt transition from oil to gas just 15 miles to 20 miles west of the giant Alpine field, located just outside the northeastern boundary of NPRA. “These new findings underscore the challenge of predicting whether oil or gas will be found in frontier areas, and the importance of analyzing the geologic characteristics and history of an area in order to understand the oil and gas resources,” explains USGS director Marcia McNutt. “As new data become available, it is important to re-evaluate the petroleum potential of an area in light of the new information.”