* Force majeure took effect on Friday
* Shell says investigating incident
* Bonny stream was due to export 316,000 bpd in November
(Adds details, trader comments)
By Alex Lawler and Nick Tattersall
LONDON/LAGOS, Nov 19 Royal Dutch Shell Plc's (RDSa.L) Nigerian venture on Friday declared force majeure on Bonny Light oil exports after a pipeline was damaged, the latest disruption to supply in Africa's top exporter.
A Shell spokesman in Nigeria said the force majeure, which frees the Anglo-Dutch company from contractual deliveries due to actions beyond its control, took effect from Friday. He gave no details on any production impact.
"Repair work will commence as soon as the cause is determined," the spokesman said. "Investigations are ongoing."
The disruption boosted oil prices, oil traders said, because Nigerian oil is priced in relation to global benchmark Brent crude [LCOc1>. Brent traded as high as $86.15 a barrel on Friday before easing by 1517 GMT to $84.33.
Bonny Light is one of Nigeria's larger crude oil streams and is popular with oil refiners in Europe and the United States.
It was scheduled to export as many as 10 cargoes in November, equal to about 316,000 barrels per day (bpd) and about 15 percent of Nigeria's expected daily oil exports this month of 2.1 million bpd.
An oil trader who buys Bonny Light said he was waiting for information about the amount of production affected. "I do expect some delays to cargoes," the trader said.
There was no immediate evidence of a link to resurgent militant activity in the oil-producing Niger Delta, where security forces rescued 19 hostages from a camp on Wednesday. [ID:nLDE6AI0H0]
A raid on an Exxon Mobil (XOM.N) Nigerian offshore oil platform on Nov. 14 had knocked out 45,000 bpd of condensate production. (Editing by Alison Birrane)
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