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.”
More Gas than Oil in NPRA
December 1, 2010