Stephen Moore: What North Dakota Could Teach California - WSJ.com

In 1995, the U.S. Geological Survey estimated 150 million "technically recoverable barrels of oil" from the Bakken Shale. In April 2008 that number was up to about four billion barrels, and in 2010 geologists at Continental Resources (the major drilling operation in North Dakota) put it at eight billion. This week, given the discovery of a lower shelf of oil, they announced 24 billion barrels. Current technology allows for the extraction of only about 6% of the oil trapped one to two miles beneath the earth's surface, so as the technology advances recoverable oil could eventually exceed 500 billion barrels.