BANGKOK -- Ample oil supplies helped send oil prices below $86 per barrel on Friday.
Benchmark oil for December delivery was down 86 cents to $85.18 a barrel at midday Bangkok time in electronic trading on the New York Mercantile Exchange.
The contract rose 32 cents to finish at $86.05 a barrel in New York on Thursday, the only day this week that oil prices have risen.
Brent crude fell $1.04 cents to $107.45 a barrel in London.
Analysts said the recent fall in oil prices can be partly attributed to ample supplies. Oil has dropped more than 7 percent in the past week.
The Energy Department said Thursday that U.S. oil supplies grew last week by 5.9 million barrels, or 1.6 percent. At 375.1 million barrels, the nation's oil inventory is 11.1 percent above year-ago levels.
"I think that's all about a scenario of more than adequate supply for the current demand level," said Ric Spooner, chief market analyst at CMC Markets in Sydney.
Traders were looking ahead to Friday's report on U.S. gross domestic product for the third quarter. Analysts are estimating that the U.S economy grew 1.8 percent. A level significantly lower than that would be negative for oil consumption prospects.
"If it is significantly weaker than that, and there is a chance of that ... that would be a little bit disappointing in terms of people's demand outlook," Spooner said.
In other energy futures trading in New York:
_ Natural gas rose 0.1 cent to $3.44 per 1,000 cubic feet.
_ Wholesale gasoline rose 1.2 cents to $2.62 a gallon.
_ Heating oil fell 1.3 cents to $3.03 a gallon.