Oil prices steadied on Wednesday, with supply disruptions in Libya and Nigeria offsetting expectations of a rise in US crude inventories, analysts said.
New York's main contract, West Texas Intermediate for delivery in May edged up eight cents to $99.27 a barrel.
Brent crude for May rose four cents to stand at $107.03 a barrel in London deals.
"Oil prices are continuing to tread water," said Commerzbank analyst Carsten Fritsch.
"Prices are finding support on the one hand from the interruptions and risks to production. On top of the continued decline in Libyan production there is now the latest escalation of violence and suspension of delivery... due to a pipeline leak in Nigeria."
He added: "At the same time, the still ample supply situation and poor economic development in the emerging economies argue against any sustained price rise. Meanwhile, crude oil stocks are being built up in the US."
Rebels pressing for autonomy for Libya's eastern Cyrenaica region have been blockading oil terminals since July.
That has led to a decline in exports from 1.5 million barrels a day to just 250,000.
Elsewhere, Anglo-Dutch oil giant Shell on Wednesday said it had declared a "force majeure" on crude oil exports from Nigeria as it struggles to repair a sabotaged pipeline.
"Force majeure" is a legal term releasing a company from contractual obligations when faced with circumstances beyond its control.
Nigeria is Africa's biggest oil producer, accounting for more than two million barrels per day.
The market is keeping an eye also on a closely-watched US energy stockpiles report to be released later Wednesday, with analysts expecting a build-up that could put downward pressure on oil prices.
Slow traffic movement at a key petroleum waterway in the United States after a ship collision that resulted in an oil spill could help push the inventories higher.
Shailaja Nair, senior managing editor of energy market information provider Platts, said that although the Houston Ship Channel was reopened, vessel movement is still not back to normal, slowing down supplies to refineries in the US Gulf Coast.
"If the refineries do not take the usual amount of crude oil, the crude stockpiles will go up," Nair told AFP.