WASHINGTON — Amid surging demand for oil, a severe bottleneck has developed in production of high-quality West African crude, alarming world leaders and demonstrating a new vulnerability in fragile oil markets.
With production declining elsewhere, consumer nations had been looking hopefully toward Nigeria. But rebels who have waged an increasingly bold campaign in the oil-rich Niger Delta have slashed the country's output in their most recent attacks.
The deepening disruptions in Nigeria represent a "huge hole in world oil markets," said Daniel Yergin, a top oil expert and chairman of the Cambridge Energy Research Associates consulting firm, who warns of an increasingly crisis-prone oil economy.
A nighttime raid by Nigerian militiamen in speedboats in mid-June forced the shutdown of a Shell offshore platform and shocked the industry, demonstrating that even production facilities far from land are no longer safe.
That attack, among others, has cast doubt on whether oil companies will continue investing billions of dollars in a region plagued by violence and corruption. And it has raised questions about whether the Bush administration has done enough to pressure Nigeria's government to find a political solution to the unrest.
The disruptions also signaled the sensitivity of the oil markets to political and security pressures at a time of tight supplies, when the smallest fluctuations can quickly drive up prices.
Violence regularly disrupts oil flows from Nigeria, Iraq and Colombia; the threat of conflict also hangs over the output of Venezuela, and Iran, Saudi Arabia and other Persian Gulf states, boosting prices.
Nigeria's petroleum infrastructure is threatened by militias motivated by anger that the country's leadership and international oil companies were not sharing the oil wealth with the impoverished residents of the Niger Delta.
But though the movement has its origins in political grievances, many experts regard the militias as youthful crime gangs that steal oil, carry out kidnappings and buy weapons in a sophisticated scheme that benefits Nigerian military and civilian leaders as well as warlord commandants.
The gangs, whose arms include surface-to-air missiles and bazookas, have learned how to siphon thousands of gallons of crude into barges and send it to the high seas for sale on world spot oil markets.
