Unrest in the Niger Delta oil fields this year, has cut about a quarter of the country's oil production. Most of the attacks on oil facilities are by locals, angry at the government for mucking up their neighborhood, then stealing all the oil revenue. The unrest is too widespread to deal with using police and troops (who are not very efficient in the best of times.) But paying off each violent group of tribesmen, while expensive, works.
October 25, 2006: Local tribesmen seized three oil facilities in the Niger Delta, forcing a shutdown. The oil company now has to negotiate a payment, to get the tribesmen out.
October 22, 2006: Seven foreign oil engineers, kidnapped 19 days ago in the Niger Delta, were released. No mention was made of ransom, but it is usually paid in these cases. The men were taken from a guarded residential compound, when a gang of 18 armed men invaded. This has not happened before, and the kidnappers appear to have been common criminals.