North Dakota oil won't be easy to get, U.S. concludes

North Dakota and eastern Montana can now boast of having the largest known oil accumulation in the lower 48 states, but the petroleum industry will have to drill deep and spend lavishly to get to it.

The U.S. Geological Survey reported Thursday that an estimated 3 billion to 4.3 billion barrels of undiscovered crude oil could be tapped from an expanse of underground shale called the Bakken Formation. The findings represent a 25-fold increase in the potential supply of “technically recoverable” oil since the agency last studied the region in 1995. Advancements in drilling and the spiraling price of crude have generated a heightened interest in squeezing oil out of the formidable Bakken.

But with the oil trapped between layers of shale 10,000 feet deep, it could take decades to develop the field, which encompasses 25,000 square miles in North Dakota, Montana, Saskatchewan and Manitoba. "It is very tough oil,” said geologist Julie LeFever of the North Dakota Geological Survey.

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