Bakken formation
The Bakken Formation (/ˈbɑːkən/ BAH-kən) is a rock unit from the Late Devonian to Early Mississippian age occupying about 200,000 square miles (520,000 km2) of the subsurface of the Williston Basin, underlying parts of Montana, North Dakota, Saskatchewan and Manitoba. The formation was initially described by geologist J. W. Nordquist in 1953. The formation is entirely in the subsurface, and has no surface outcrop. It is named after Henry O. Bakken (1901–1982), a farmer in Tioga, North Dakota, who owned the land where the formation was initially discovered while drilling for oil.
| Bakken Formation | |
|---|---|
| Stratigraphic range: Late Devonian-Early Mississippian ~ | |
Cut Bakken core samples | |
| Type | Geological formation |
| Unit of | Three Forks Group |
| Underlies | Madison Limestone |
| Overlies | Wabamun, Big Valley & Torquay Formations |
| Area | 200,000 square miles (520,000 km2) |
| Thickness | up to 40 metres (130 ft) |
| Lithology | |
| Primary | Shale, dolomite |
| Other | Sandstone, siltstone |
| Location | |
| Coordinates | 48.3929°N 102.9399°W |
| Region | Central North America |
| Country | Canada United States |
| Extent | Williston Basin |
| Type section | |
| Named for | Henry O. Bakken (1901-1982) |
| Named by | J.W. Nordquist |
| Year defined | 1953 |
Map of the Bakken Formation reservoirs in the US portion of the Williston Basin (Saskatchewan is north border). Prior to 2007, most oil came from the Elm Coulee Oil Field | |
Besides the Bakken Formation being a widespread prolific source rock for oil when thermally mature, significant producible oil reserves exist within the rock unit itself. Oil was first discovered within the Bakken in 1951, but past efforts to produce it have faced technical difficulties.
In April 2008, a USGS report estimated the amount of recoverable oil using technology readily available at the end of 2007 within the Bakken Formation at 3.0 to 4.3 billion barrels (680,000,000 m3), with a mean of 3.65 billion. Simultaneously the state of North Dakota released a report with a lower estimate of 2.1 billion barrels (330,000,000 m3) of technically recoverable oil in the Bakken. Various other estimates place the total reserves, recoverable and non-recoverable with today's technology, at up to 24 billion barrels. A recent estimate places the figure at 18 billion barrels. In April 2013, the U.S. Geological Survey released a new figure for expected ultimate recovery of 7.4 billion barrels of oil.
The application of hydraulic fracturing and directional drilling technologies has caused a boom in Bakken oil production since 2000. By the end of 2010, oil production rates had reached 458,000 barrels (72,800 m3) per day, thereby outstripping the pipeline capacity to ship oil out of the Bakken. There is some controversy over the safety of shipping this crude oil by rail due to its volatility.
This was illustrated by the 2013 Lac-Mégantic rail disaster, in which a unit train carrying 77 tank cars full of highly volatile Bakken oil through Quebec from North Dakota to the Irving Oil Refinery in New Brunswick derailed and exploded in the town centre of Lac-Mégantic. It destroyed 30 buildings (half the downtown core) and killed 47 people. The explosion was estimated to have a one-kilometre (0.62 mi) blast radius.
As of January 2015, estimates varied on the break-even oil price for drilling Bakken wells. The North Dakota Department of Natural Resources estimated overall break-even to be just below US$40 per barrel. An analyst for Wood Mackenzie said that the overall break-even price was US$62/barrel, but in high-productivity areas such as Sanish Field and Parshall Oil Field, the break-even price was US$38–US$40 per barrel.