Bakken Shale oil extraction status

Bakken, a formation of shale source rock areas, covering North Dakota, Montana and Saskatchewan 200,000 square miles, is the largest known North American light crude oil storage area. In 1951 the first oil discovery in this area, but due to technical limitations, until recently more oil to be found. Although Bergen shale zone may have one hundred billion barrels of oil reserves, but due to the oil shale itself is trapped, it is difficult extraction.
In 2008, the U.S. Geological Survey released a report estimating that the Bakken region, technically recoverable oil volume nearly 3,000,000,000 to 43 billion barrels. This is obviously a rather large oil reserves, but far less than the rock formations of the amount of oil contained. In recent years, oil extraction technologies have made the Bakken region's oil production increased significantly, the most critical technology,  Hydraulic fracturing , or " hydraulic fracturing ," played an important role.
To the end of 2010, shale oil production has increased structural 458,000 barrels per day, which gives the local infrastructure, and even oil output capacity causing serious burden. Increasing oil production has prompted some industry experts are beginning to conclude that the original USGS estimate 3000000000-43 barrels too little, perhaps these experts inference is correct, the latest estimation techniques have come to the oil production can be up to 240 billion barrels. Of course, the decision depends on oil production is the key to the percentage of technically recoverable. Estimated that the range is from 1% to 50%, this is obviously a very wide amplitude.