The oil price rallied towards its highest level this year on Wednesday, after a drop in U.S. crude inventories and as the prospect of the loss of Iranian supply added to concerns over the delicate balance between consumption and production.
The Energy Information Administration said Wednesday that U.S. crude oil inventories dropped by 5.3 million barrels last week.
"We think oil market fundamentals are increasingly supportive of crude prices, at least at current levels," said Gordon Gray, HSBC's global head of oil and gas equity research.
"While we aren't explicitly forecasting Brent to rise to $100 a barrel, we see real risks of this happening. The fact that much higher supply is already needed from the likes of Saudi Arabia - and the low levels of spare capacity remaining - leave the global system highly vulnerable to any further significant outage."
Outside the United States, traders have been focusing on the impact of U.S. sanctions against Iran that will target oil exports from November.
"Iran is increasingly becoming the preoccupation of the crude market. The last couple of weeks have seen the expected squeeze on Iranian crude flows taking shape, with overall outflows down markedly," consultant JBC Energy said.