The Bakken Formation is one of the largest contiguous deposits of oil and natural gas in the United States. It is an interbedded sequence of black shale, siltstone and sandstone that underlies large areas of northwestern North Dakota, northeastern Montana, southern Saskatchewan and southwestern Manitoba. The formation consists of a lower shale member, a middle sandstone member and an upper shale member. The shales are organic-rich and of marine origin. They are rich source rocks for oil and natural gas. All three members of the Bakken Formation have been known to yield oil and natural gas.
Just a few years ago in 2007, the Bakken was considered a marginal to submarginal resource because the oil and natural gas are locked in a rock formation with a low permeability. However, advances in drilling and recovery technology such as horizontal drilling and hydrofracturing have transformed the Bakken into a prolific oil and natural gas producer.
Since then the Bakken has propelled North Dakota oil production to record levels, moving the state to the position of #2 oil producer in the United States. The only state that produces more crude oil is Texas.
The Bakken Formation has also given a major boost to the North Dakota economy and reduced unemployment in the state to very low levels. The Bakken resource is expected to be productive for decades and make a major contribution to the energy independence of the United States.