North Dakota oil drillers have surpassed a milestone of half a million barrels of oil a day.
State Mineral Resources Director Lynn Helms says North Dakota's oil patch accounts for about 10 percent of total U.S. crude oil production. That's up from just 1 percent less than five years ago.
The state Industrial Commission says crude production in November totaled 510,000 barrels a day, or about 150,000 more barrels than in November 2010.
North Dakota went from the ninth-biggest producer in 2006 to fourth in 2009. Helms says North Dakota could be the nation's No.2 oil producer early next year, surpassing California and Alaska, and trailing only Texas.
Helms says the state's record production could be higher but it has been slowed by the lack of hydraulic fracturing crews.