Petroleum industry in Nigeria to transport the crude oil. Also because of the lack of highly productive fields, money from the jointly operated (with the federal government) companies is constantly directed towards petroleum exploration and production. Nigeria's petroleum is classified mostly as "light" and "sweet", as the oil is largely free of sulphur. Nigeria is the largest producer of sweet oil in OPEC. This sweet oil is similar in composition to petroleum extracted from the North Sea. This crude oil is known as "Bonny light". Names of other Nigerian crudes, all of which are named according to export terminal, are Qua Ibo, Escravos blend,
Nigerian Civil War of 250,000 pounds. The news of this payment reached the Federal government, which immediately extended the shipping embargo to oil tankers The Nigerian government also made it clear to Shell-BP that it expected the company to pay all outstanding oil royalty immediately. With the stalling on the payment for Biafra government ask Shell-BP to stop operations in Biafra and took over from the company. Towards the end of July 1967, Nigerian federal troops and marines captured Bonny Island in the Niger Delta, thereby taking control of vital Shell-BP facilities. Operations began again in May 1968, when Nigeria captured Port Harcourt.