Anglo-Dutch oil group Shell said Tuesday it may not meet contractual obligations on certain exports from Nigeria because of theft and damage to key pipelines in the country's oil region.

"Effective 1400 hours Friday 19th October 2012, SPDC JV declared force majeure on Bonny and Forcados loadings," the company said in a statement.

SPDC is Shell's Nigerian joint venture.

Force majeure is a legal term releasing a company from contractual obligations due to circumstances beyond its control.

"Bonny loadings are affected as a result of production deferment caused by the fire incident on a bunkering ship on the Bomu-Bonny Trunkline and production deferment from a third party producer because of flooding," Shell said.

It said exports from Forcados were affected by damage caused by suspected bunkering - the term for oil theft - on the Trans Forcados pipeline and the Brass Creek trunkline.

Although Shell did not disclose the volume of crude exports affected, industry sources said both Bonny and Forcados account for substantial percentage of Nigeria's total oil production.

Shell said it was working to repair the pipelines as soon as possible.

Nigeria is Africa's largest oil producer, exporting between 2.0 and 2.4 million barrels per day in recent months.

Pipeline damage and associated spills are common in the Niger Delta region as a result of oil theft to feed the lucrative black market.

Militants claiming to be fighting for a fairer distribution of oil revenue have also regularly blown up pipelines, though such attacks have decreased since a 2009 amnesty deal.