A new government assessment of the Bakken and Three Forks formations found that they contain an estimated mean of 7.4 billion barrels of undiscovered, technically recoverable oil, twice as high as the previous estimate.
The assessment released Tuesday also found an estimated 6.7 trillion cubic feet of natural gas, three times the previous estimate.
The Bakken Formation was last assessed by the U.S. Geological Survey in 2008. It is located in the Williston Basin and spreads across parts of Montana, North Dakota and South Dakota.
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Brenda Pierce, energy resources program coordinator for the U.S. Geological Survey, said the higher estimates are almost entirely due to the inclusion of the Three Forks Formation. It wasn’t assessed in 2008 because it was generally considered to be non-productive then, she said.
“The Three Forks was the big unknown,” Pierce said during a conference call to announce the latest assessment. “Since then, there’s been an explosion (of interest). The Bakken is still big, but the Three Forks is the up and coming.”
The U.S. Geological Survey periodically assesses all U.S. petroleum basins, information that Interior Secretary Sally Jewell said is made available to both state and federal land managers and other government employees as well as industry.
The economy and national security depend on reliable estimates, she said during the conference call, noting that increasing domestic energy production, coupled with recent declines in energy demand, have dropped foreign oil imports to less than 40 percent of U.S. use, the lowest level since 1988.
According to the new assessment, the Bakken Formation has an estimated mean oil resource of 3.65 billion barrels of oil, and the Three Forks Formation has an estimated mean resource of 3.73 billion barrels of oil.
Suzette Kimball, acting director of the U.S. Geological Survey, said that does not include known fields or fields currently in production.
U.S. Sen. John Hoeven, R-N.D., had asked for the updated assessment in 2011. His office said he wanted the updated assessment in order to spur investment in infrastructure including housing, hotels and retail services to serve the rapidly growing population.
The estimated resource for the Bakken remained unchanged from 2008, but Pierce said that doesn’t include all the reserves booked in the past five years, making the total amount of available oil larger.
Still, she said, “I don’t want people to think this is immediately consumable, and all this will be immediately recoverable.”
The assessment counted oil considered recoverable using current technology. That doesn’t mean it’s necessarily economical to do so.
“It’s more expensive to drill. It takes more technology,” Pierce said. “But it’s definitely the largest conventional resource assessment in the United States.”
The impact has shown up in the U.S. Census count — Williston, N.D. and Dickinson, N.D. were No. 1 and No. 3 respectively among the fastest-growing cities with populations between 10,000 and 49,999 from 2011 to mid-2012 — and sparked an infrastructure gold rush as company hurried to provide everything from pipelines and railyards to hotels and laundromats for oilfield workers.