Bakken Formation

by Matt Williams on September 17, 2010

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Bakken Formation

Bakken Formation Map

There has certainly been a lot of news lately about this thing called the “energy crisis”. In essence, we’re being told that fossil fuels are running low, that we need to start thinking green and thinking about alternative fuels. However, there’s also a lot of talk about the Alberta Tar Sands and how these might meet our energy needs for the foreseeable future. But would it surprise you to know that there is another major oil deposit, one that sits beneath the unlikely place known as The Prairies?

It’s called the Bakken Formation, and it is a rock unit occupying about 520,000 km2 of the subsurface of the Williston Basin, underlying parts of Saskatchewan, Manitoba, Montana, and North Dakota. On the geologic timescale, the rock formation is believed to date from the late Devonian to Early Mississippian age, from roughly 416 to 360 million years ago. It was discovered in 1953 by a geologist named J.W. Nordquist and named after Henry Bakken, owner of the Montana farm where Nordquist first drilled. This rock formation consists of three members or strata: the lower shale, middle dolomite, and upper shale.

Oil was first discovered there in 1951, but pumping it met with difficulties. This is due to the fact that the oil itself is trapped in layers of non-porous shale, making the process both difficult and expensive. While it was postulated as early as 1974 that the Bakken could contain vast amounts of petroleum, it wasn’t until Denver-based geologist Leigh Price did a field assessment for the U.S. Geological Survey (USGS) in 1995 that official estimates were made. Price estimated in 1999 that the Bakken contained between 271 and 503 billion barrels of petroleum.

Impressive? Keep in mind that the percentage of oil that might be extracted is debatable. In 1994, estimates ranged from as low as 1% to Price’s estimate of 50%. A more recent report filed in 2008 by the USGS places the amount at between 3.0 to 4.3 billion barrels (680,000,000 m3), with a mean of 3.65 billion. This represents a twenty-five fold increase from the estimates made in 1995. Horizontal well and hydraulic fracturing technology helped, adding about 70 million barrels of production in 7 years in Montana and North Dakota. By 2007, Saskatchewan was also experiencing a boom, producing five million barrels in that year, which was up 278,540 barrels in 2004.

Will this solve the “energy crisis”? Hard to say. Because of the highly variable nature of shale reservoirs and shale drilling, and the fact that per-well rates seem to have peaked, it seems unlikely that total Bakken production will grow much further or affect the imports of foreign oil.

We have written many articles about the Bakken Formation for Universe Today. Here’s an article about Alternative Energy Sources, and here’s an article about harvesting solar power from space.

If you’d like more info on the Bakken Formation, check out the U.S. Geological Survey Homepage. And here’s a link to NASA’s Earth Observatory.

We’ve also recorded an episode of Astronomy Cast all about planet Earth. Listen here, Episode 51: Earth.

Sources:
http://en.wikipedia.org/wiki/Bakken_Formation – cite_note-usgs.gov-3
http://www.cbc.ca/money/story/2008/05/23/f-langton-bakken.html
http://www.theoildrum.com/node/3868
http://www.thestar.com/Business/article/414164

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