An oil platform in the Norwegian sea. Marcel Mochet/AFP/Getty Images hide caption

itoggle caption Marcel Mochet/AFP/Getty Images

An oil drilling rig is seen near Ray, N.D., last September. The well is being drilled into the Bakken Formation, one of the largest contiguous deposits of oil and natural gas in the United States. Karen Bleier/AFP/Getty Images hide caption

itoggle caption Karen Bleier/AFP/Getty Images