WASHINGTON, May 20 (UPI) -- New information about oil and gas reserves in the Bakken formation in North Dakota and Montana warrants a new federal assessment, an official said.
The U.S. Geological Survey announced it would review its 2008 estimate of undiscovered, technically recoverable oil and natural gas in the Bakken formation.
The USGS in 2008 estimated there were 3 billion to 4.3 billion barrels of oil in the U.S. part of the formation, making it larger than all other oil assessments in the Lower 48 and the largest continuous oil accumulation ever assessed by the federal government.
The 2008 estimate was 25 times greater than the 1991 estimate. New geological models, drilling and discoveries yielded greater reserve predictions for the formation.
The USGS will start its review in October. It should take about two years to complete the study depending on funding. Drilling and production activity in the region will continue during the assessment period.
"The new scientific information presented to us from technical experts clearly warrants a new resource assessment of the Bakken," USGS Energy Resources Program Coordinator Brenda Pierce said in a statement.
