The Organization of the Petroleum Exporting Countries (OPEC;, )'s a cartel of twelve countries made up of Algeria, Angola, Ecuador, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, the United Arab Emirates, and Venezuela. The cartel has maintained its headquarters in Vienna since 1965, and hosts regular meetings among the oil ministers of its Member Countries. Indonesia withdrew its membership in OPEC in 2008 after it became a net importer of oil, but stated it'd likely return if it bec… (More on Opec)