Iraqi workers are seen at the Rumaila oil refinery, near the city of Basra, in 2009.

Surging U.S. oil production was expected to drive oil prices lower this year, but a confluence of geopolitical events—particularly a Sunni militant uprising in Iraq—could now drive already high prices even higher and keep them there.

The situation in Iraq has become increasingly tense and violent with Al Qaeda-linked groups seizing control of two key cities, Mosul and Tikrit, in the past two days. The group, the Islamic State of Iraq and Syria, so far has targeted a northern pipeline—the Kirkuk-Ceyhan oil pipeline, but the activity has so far not spread to other energy infrastructure.