This short article is an interesting discussion of oil prices. It also has a chart showing what other countries need per barrel to make money on oil.

Our shale oil plays make money from $60 (maybe) to around $80 per barrel. Even the lowest OPEC country needs $80 minimum, and it goes up quickly from there.

Our ability to drill for cheap oil gives us the most political leverage of any country in the world.

http://www.businessweek.com/articles/2014-10-30/it-looks-like-80-oil-is-here-to-stay#r=read