The U.S. Energy Information Administration said stockpiles of crude oil rose during the week by 3.8 million barrels to 364.5 million.
Finance ministers from the Group of Seven nations this week said they would keep markets amply supplied.
Supply worries increased during the week with Hurricane Isaac threatening Gulf Coast delivery and refining, a strike by Norwegian oil industry service workers and an international embargo against Iran meant to pressure the government to shut down an alleged nuclear weapons program.
On the New York Mercantile Exchange Friday, West Texas Intermediate crude oil for October delivery added $1.92 to settle at $96.47. Natural gas added 4.6 cents to $2.965 per million British thermal units.
Home heating oil added 0.451 cents to $3.1696 per gallon. Reformulated blendstock gasoline gained 0.648 cents to $3.1056 per gallon.
At the pump, the average price for a gallon of regular unleaded gasoline was $3.829 per gallon Friday, up from Thursday's $3.826, AAA reported.