Current secretary-general Abdalla Salem el-Badri was set to retire since 2013, but had stayed on because the cartel was not able able to agree on a new leader. Earlier this week, the 13-nation group announced it may choose a new secretary-general at its meeting next week in Vienna.
"There is a pile of candidates for this post, including African and Middle Eastern ministers. It is believed that the best chance belongs to the Indonesian Minister," the source said in Vienna.
Indonesia, Southeast Asia's largest economy, had been an OPEC member for almost 50 years until it suspended its membership in 2009 shortly after it turned into a net oil importer as its output dropped due to a lack of investment from foreign companies. Indonesia rejoined OPEC in December, which was highly welcomed by the OPEC member states.