State officials say an oil formation in southwestern North Dakota believed to be similar to the Bakken shale formation is drawing interest.
Department of Mineral Resources geologist Stephan Nordeng says the Tyler Formation above the Bakken encompasses nearly all of western and southwestern North Dakota and extends into South Dakota.
State Mineral Resources Director Lynn Helms says the Tyler Formation is most likely one-third to one-half the size of the Bakken in terms of coverage area and oil reserves.
The Bakken covers some 25,000 square miles in North Dakota, Montana, Saskatchewan and Manitoba. Officials believe more than 4 billion barrels of oil can be recovered using current technology.