North Dakota oil production has more than doubled in the past two years, and the state's sweet crude now feeds refineries on the East, West and Gulf coasts.
State records show North Dakota oil drillers produced an average of about 558,000 barrels daily in February, up from 262,000 barrels in February 2010.
Records show the state had 6,726 producing wells in February, or nearly 2,100 more wells than in February 2010.
North Dakota Pipeline Authority director Justin Kringstad says 25 percent of the state's oil production is moving by rail to coastal refineries. Two years ago, only a small percentage of the state's crude moved by rail.