|What Is The Bakken Formation And How Big Is It?
Map Of The Bakken shale In The Williston Basin
What Is The Bakken Shale?
The Bakken shale (pronounced "bokken") is an oil and natural gas bearing layer of rock (shale) located in the Williston Basin of the North Central part of the United States and Canada.
The Bakken shale is the largest oil find in U.S. history according to the U.S. Geological Survey Administration.
How large is the Bakken shale? It lies beneath much of North Dakota, eastern Montana, northwestern South Dakota, as well as the lower part of Manitoba and Saskatchewan.
It covers over 24,000 square miles or about the size of the state of West Virginia. It holds the promise to becoming an integral part of America's domestic energy supply.
News Story About the Bakken Shale
The Bakken shale formation is named after Henry Bakken, the landowner of the property where the first well was drilled penetrating the Bakken in Williams County, North Dakota in 1953. It was given the name by geologist J.W. Nordquist.
The Bakken shale is over 11,000 feet at the center of the formation and rises to only 3100 feet across the Canadian border in Manitoba and Saskatchwan. It was formed during the upper Devonian and lower Mississippian period approximately 350 to 417 million years ago when the area was part of a vast inland sea.
Throughout most of the Bakken formation it is composed of three distinct members. The first is a layer approximately twenty three foot deep layer of blackish marine shale, the second layer which is approximately eighty five foot thick and composed of interbedded limestone, siltstone, sandstone and dolomite and the bottom layer which is a dark black marine shale approximately fifty feet thick. While this is a generalization of the formation this is found very commonly.
The two shales are rich in an organic material called Kerogen. Kerogen, when heated (thermogenic) or broken down by organic means (biogenic) gives off oil and natural gas.
The Bakken shale is capped by a very thick limestone called the Lodgpole limestone. It is because of this capping effect that there is so much gas trapped in the shale. The Bakken shale is what geologists consider "thermally mature." The oil found throughout most of the Bakken is 41 gravity
Horizontal drilling and hydraulic fracturing utilizing a proppant or frac sand to prop up and keep fissures open are the primary methods being utilized in the Bakken shale. Currently over 63% of the oil being produced in North Dakota is from horizontal wells that have utilized hydraulic fracturing.
How Much Oil Does The Bakken Shale Formation Hold?
How much oil does the Bakken Formation contain? In early 2008 the USGS, as part of a study requested by the state of North Dakota, released findings that from 3.0 to 4.3 billion barrels of oil could be recovered from approximately 167 billion barrels total in the shale. Later the state of North Dakota released it's own findings of a study they conducted and declared that 2.1 billion barrels of oil could possibly be recovered with existing technology.
The USGS stated in April, 2008 that the Bakken shale is the largest contiguous reservoir of oil it has ever assessed in the United States.
There are many promising new technologies that could extract much more of the total 167 billion barrels that the Bakken shale contains, if the cost of oil is high enough to justify employing them. Steam flooding, CO2 injection and other methods could one day be used in the Bakken shale.
At the current price of oil these methods are cost prohibitive but one day that will change. For the meantime, even with current technology the Bakken shale is proving to be a very rich oil play.
Among the major players in the Bakken shale are Continental Resources which holds leases of nearly a half - million acres in Montana and North Dakota, making the company the biggest leaseholder in the Bakken shale play thus far.
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In July of 2008 Continental Resources reported that it's first well was producing at a rate of 693 barrels of crude oil equivalent per day. A second well, the Mathistad 1-35-H is currently producing 1095 barrel of oil equivalent per day. The barrels of oil equivalent factored in ten percent natural gas counted as equivalent oil production. Most wells are producing ninety percent oil and ten percent natural gas.
Economic Impact of The Bakken Shale Formation
There are currently over 4000 producing oil wells in North Dakota alone, producing over 135,000 barrels per day. Each well being drilled employs more than one hundred and twenty direct and indirect workers to complete.
Oilfield jobs pay, on average, twice the normal wage in the area. The cost of drilling a well was reported by the American Petroleum Institute to be 4.1 million in 2006. Much of that money flows into the local economy in the Bakken shale play area.
Revenue from oil and gas production is taxable and this helps fund municipal works, hospitals and schools in North Dakota, Montana and Canada.
Large Is The Bakken Shale? The Upper red zone indicated the possibly productive
area. There are several shale formations in the United States similar
to the Bakken shale. Most of these are primarily natural gas producers. Among
these analog formations are the Marcellus shale, Barnett shale, Eagle Ford shale
(which produces both oil and gas), the New Albany Shale and the Haynesville
shale. For more information on other shale oil formations such as the
Eagle Ford shale and the New Albany shale see the following articles:
How Large Is The Bakken Shale? The Upper red zone indicated the possibly productive area.
There are several shale formations in the United States similar to the Bakken shale. Most of these are primarily natural gas producers.
Among these analog formations are the Marcellus shale, Barnett shale, Eagle Ford shale (which produces both oil and gas), the New Albany Shale and the Haynesville shale.
For more information on other shale oil formations such as the Eagle Ford shale and the New Albany shale see the following articles: