MSN:Oil advances as Isaac approaches US Gulf Coast
Brent North Sea crude for delivery in October gained 32 cents to $112.58 a barrel in late morning London deals.
New York's main contract, light sweet crude for October won 69 cents to $96.16 a barrel.
"Crude oil prices corrected higher on Tuesday, supported by a weaker US dollar and a rebound in the global equity markets," said Sucden analyst Myrto Sokou.
A weaker greenback makes dollar-priced crude cheaper for buyers using stronger currencies, which tends to stimulate demand and spark higher prices.
"All eyes remain on the Tropical Storm Isaac that might cause further issues with a potential serious disruption (for) oil refineries on the US Gulf Coast," added Sokou.
Six of 12 refineries in the path of Isaac had shut down or were shutting down operations, affecting roughly 17 percent of total Gulf coast refining capacity, the US Department of Energy said late Monday.
About 78 percent of crude oil production and about 48 percent of natural gas production in the heart of the US refining and offshore energy industry had been shut in by 1900 GMT, it added.
New Orleans on Tuesday braced for another hurricane as a strengthening Tropical Storm Isaac drew near, seven years after Hurricane Katrina left 1,800 dead.
The US National Hurricane Center said in its 0900 GMT advisory that Isaac was "on the verge" of becoming a hurricane, warning of a "significant storm surge and freshwater flood threat to the northern Gulf coast."
The Miami-based NHC predicted the centre of the storm would be over the Louisiana coast by late Tuesday or early Wednesday.