Guwahati: It was a pilgrimage for the Organisation of the Petroleum Exporting Countries (OPEC) secretary general Mohammad Sanusi Barkindo and his team when they visited Digboi Refinery, which is the oldest operating refinery in the world, for two days from April 13.

Indian Oil Corporation on Tuesday said a four-member OPEC delegation led by secretary general Mohammad Sanusi Barkindo visited the refinery.

OPEC is an inter-governmental organisation, created at the Baghdad Conference on September 10-14, 1960, by Iran, Iraq, Kuwait, Saudi Arabia and Venezuela. It is based in Vienna.

Barkindo and the delegation met Union minister for petroleum and natural gas Dharmendra Pradhan in New Delhi on April 10. The delegation was given a guided tour of the Digboi Centenary Museum and told of incredible facts that led to the discovery of oil in the late 19th century.