The Bakken and Three Forks formations contain twice as much oil as initially thought, according to a recent Interior Department study.

The U.S. Geological Survey (USGS) said an assessment found the formation contains about 7.4 billion bbl. of “undiscovered, technically recoverable oil.” The Bakken has about 3.65 billion bbl. of oil resources, while Three Forks contains an additional 3.73 bbl. in resources, says the USGS. Those figures are well above the 3.65 billion bbl. of estimated undiscovered Bakken oil from the survey’s 2008 assessment. Little data previously existed in the Three Forks, which was initially considered to be unproductive. New drilling technologies changed this.

“These world-class formations contain even more energy resource potential than previously understood, which is important information as we continue to reduce our nation’s dependence on foreign sources of oil,” Secretary of the Interior Sally Jewell said in a public statement.

“We must develop our domestic energy resources armed with the best available science, and this unbiased, objective information will help private, nonprofit and government decision makers at all levels make informed decisions about the responsible development of these resources.”

As well, the Bakken and Three Forks formations are estimated to contain about 6.7 trillion cubic feet (Tcf) of undiscovered, technically recoverable natural gas, as well as 0.5 billion bbl. of undiscovered, technically recoverable NGLs. These figures are three times higher than the 2008 estimate, again thanks to the new possibilities for Three Forks.

The new data will help the Obama administration make science-based decisions when developing the country’s energy resources, the USGS said.

“The USGS undertook this assessment of the Bakken and Three Forks formations as part of a nationwide project assessing U.S. petroleum basins using standardized methodology and protocol,” said Suzette Kimball, acting director of the USGS.

“Through this improved understanding of our energy resources, government, industry and citizens are able to understand our domestic energy mix and make wiser decisions for the future.”