The San Ramon-based company's lockup in the Niger Delta came just a few days after gunmen seized four of its American subcontractors from an offshore vessel amid an outbreak of militant attacks that have disrupted Africa's biggest oil-producing country.
"We are working with all appropriate government agencies and community leaders to try and restore peace and stability ... in the area and will resume normal business operations when this occurs," Chevron said in a statement Friday.
Chevron's U.S. workers are particularly vulnerable. Nearly 100 foreigners have been kidnapped in Nigeria since the beginning of the year. Most were released after a ransom was paid.
The company didn't specify how many workers were affected by its decision, let alone their nationalities.
The temporary suspension of some drilling, logistical support and maintenance work won't immediately affect Chevron's production in the Niger Delta, according to today's statement.
Chevron produced an average of 137,000 crude oil barrels per day from 30 fields in the region during 2006. That accounted for about 5 percent of Chevron's total production last year.
Nigeria's recent turmoil, which included the bombing of key pipelines, already has curtailed production in the oil-rich region by nearly 100,000 barrels per day and contributed to this week's increase in crude prices.
That doesn't bode well for the United States, which relies on Nigeria as one of its major sources for oil. The $3-per-gallon price for gasoline in many parts of the United States already appears to be straining the nation's economy as consumers tighten their purse strings so they can afford to fuel their cars.
In contrast to the United States, much of Nigeria lives in poverty, without electricity or even clean drinking water. Those decrepit conditions, combined with a backlash to perceived government corruption, triggered the latest eruption of violence.
The militant groups orchestrating the havoc say they are fighting for a larger slice of Nigeria's oil revenue, as well as the release of two leaders imprisoned on treason and corruption charges.
Chevron shares climbed $1.85, or 2.4 percent, to $80.04 today.
