Iran is a member of the Organization of the Petroleum Exporting Countries (OPEC), and 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 is the fourth-largest exporter of crude oil globally after Saudi Arabia, Russia, and Norway. 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.