Shell "resumed production at Bonga yesterday after completing the scheduled statutory inspection and maintenance works," it said in a statement.
"The maintenance works, which commenced on February 28 this year, were executed safely and within schedule. Production will be gradually ramped up over the coming weeks."
Production at Bonga, which lies 120 kilometres (75 miles) offshore, started in November 2005. It can also produce 150 million cubic feet of gas per day.
Nigeria is an OPEC member and Africa's largest oil producer, currently producing around 2.4 million barrels per day.
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