Benchmark oil for November delivery was down 38 cents to $103.69 per barrel at late afternoon Bangkok time in electronic trading on the New York Mercantile Exchange.
A report from the American Petroleum Institute showed an increase in oil supplies for the week ending Sept. 27. Stocks rose by 356,000 barrels to 363.7 million barrels from the prior week, suggesting a weakening in demand.
The price of oil rose the most in two weeks Wednesday, on the prospect of more oil shipping between a key U.S. Midwest hub and the Gulf Coast. The contract jumped $2.06, or 2 percent, to close at $104.10 on the Nymex on Wednesday.
Reports said that Transcanada is close to completing work on the southern portion of its Keystone pipeline expansion. That could mean as much as 700,000 barrels a day moving out of Cushing, Oklahoma, the pricing point for U.S. benchmark oil. The additional demand is likely to boost oil prices all else held equal.
Brent crude, a benchmark used to price imported crude used by many U.S. refineries, fell 14 cents to $109.05 in London.
In other energy futures trading on Nymex:
_ Wholesale gasoline rose 1 cent to $2.638 per gallon.
_ Natural gas rose 1.7 cent to $3.559 per 1,000 cubic feet.
_ Heating oil rose 0.5 cent to $2.998 per gallon.
Information from the Associated Press was used in this report.