A Shell spokesman said in a statement that its Nigerian subsidiary has declared “force majeure” on its Forcados crude shipment from October until December.

The term is used when it is impossible for an oil company to cover the promised supply from the field.

Tony Okonedo says the Trans Forcados pipeline recorded a leak Thursday which had been caused by explosives.

Okonedo said that at the same time Shell was lifting a Bonny Light force majeure declared on Aug. 23.

Shell’s pipelines run across Nigeria’s oil-rich region of swamps, mangroves and creeks.

Nigeria is a top supplier of crude to the US