Iran, a member of the Organization of the Petroleum Exporting Countries (OPEC), ranks among the world’s top three holders of both proven oil and natural gas reserves. Iran is OPEC’s second-largest producer and exporter after Saudi Arabia, and in 2008 was the fourth-largest exporter of crude oil globally after Saudi Arabia, Russia, and the United Arab Emirates. Natural gas accounts for half of Iran’s total domestic energy consumption, while the remaining half is predominately oil consumption. The continued exploration and production of the offshore South Pars natural gas field in the Persian Gulf is a key part of Iran’s energy sector development plan.