New York's main contract, light sweet crude for delivery in October, shed 51 cents to $94.98 a barrel and Brent North Sea crude for October was 11 cents higher at $112.65.
Fears about disruption to supply in the US Gulf from Hurricane Isaac had depressed prices but in the end proved unfounded, said Sanjeev Gupta, who heads the Asia-Pacific oil and gas practice at Ernst and Young.
"Most of the production facilities were shut down in advance of the storm, but early reports indicated fairly limited supply disruptions, thus taking some of the pressure off prices," he told AFP.
The Gulf of Mexico is the hub of US offshore energy production, accounting for 23 percent of crude oil output and 7.0 percent for natural gas.
The Gulf coast's facilities also have more than 40 percent of total US petroleum refining capacity and 30 percent of natural gas processing plant capacity.