Your link shows Baaken oil production of 660,000 barrels per day in late 2012, versus U.S. consumption of 20 million barrels per day.
The US does not consume 20 MMBPD of oil.
US Petroleum Product Supplied
http://www.eia.gov/dnav/pet/pet_cons_psup_dc_nus_mbblpd_m.htm
While the total liquids is 18~19 MMBPD, that includes natural gas liquids, ethanol and the like. The products refined from oil are around 16 MMBPD.
Texas and other locations are also increasing in production. We are not dependent only on one or two fields. Texas has increased by a million barrels per day in about 2 1/2 years.
Texas Field Production of Crude Oil
http://www.eia.gov/dnav/pet/hist/LeafHandler.ashx?n=PET&s=MCRFPTX2&f=M