Definitely Alaska.
Which doesn't make sense because building the infrastructure to produce oil is one of the most expensive parts of production. One reason Mexico's petrol resources remain untapped is because of the debt they would have to accumulate to just build the structure to get to and transport, not even refine, oil.

What a lot of our politicians miss is that there are alternatives to oil, the most unpopular being, everyone cut back and the government give everyone incentive to change... such as, giving drivers & corporations, credits to convert to NGV or other alternative fuels/transportation methods. Providing those who use oil for heat with credits to add photovoltaic tile, solar heating, tankless water heaters, better insulation, switch to energy efficient appliance... there are so many ways to reduce consumption. Perhaps any are better options than attempting to find a way to further rely on a finite resource.