Are the oil reserves in Montana and North Dakota for real?

The Bakken Shale formation underlies large areas of Montana, North Dakota, South Dakota, and Saskatchewan, Canada. It is a known prolific oil and gas source. The oil resources in the Bakken Shale are estimated to be among the largest in the world. The U.S. Geological Survey (USGS) estimated that the Bakken contains 7.3 billion barrels of oil, 6.3 billion barrels of natural gas liquids, and 1.3 trillion cubic feet of natural gas. The development of the Bakken Shale has led to a significant increase in oil production in the United States.