Benchmark crude for October delivery was up 48 cents to $97.65 a barrel at late afternoon Bangkok time in electronic trading on the New York Mercantile Exchange. The contract rose 63 cents to $97.17 on the Nymex on Tuesday.
Brent crude was up 82 cents at $115.58 on the ICE futures exchange in London.
Oil prices have been caught between the push-pull of two events: the so-called shoulder period for fuel demand, and the start of a two-day meeting of the Federal Reserve's Open Market Committee.
Oil prices trend lower during shoulder periods — the time of year between summer, when gasoline is in high demand as Americans take to the road for vacation, and the winter when there is strong demand for heating oil.
But Fed action to help the U.S. economy might mean more demand for oil and other energy products — and higher fuel prices.
Another impetus for oil prices to rise came out of Germany on Wednesday, when the country's high court gave the government the go-ahead to participate in a European bailout fund.
In other trading on Nymex, heating oil rose 2 cents to $3.205 per gallon. Wholesale gasoline gained 2.4 cents to $3.068 per gallon. Natural gas increased 2 cents to $3.011 per 1,000 cubic feet.