Tony Machacek, an oil trader at Jefferies in London, said that many traders were buying options to insure against prices falling to $80, reflecting uncertainty in the markets.
The overall trend for demand has been weak this year.
London-based consultancy Energy Aspects forecasts demand growth for 2014 at around 1 million barrels per day below supply growth, oil analyst Virendra Chauhan told the Reuters Global Oil Forum.
Libyan output has increased rapidly since the summer, while conflict in northern Iraq has failed to dent supply. Islamic State militants have so far failed to make an impression in the country's southern oil-producing provinces.
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The Organization of the Petroleum Exporting Countries (OPEC) has not given any formal indication that it will cut supply at or before its Nov. 27 meeting.
Many analysts expect OPEC to cut production if the oil price approaches $90.
"The market is discounting any supply disruptions that we've seen in Libya and Nigeria. I think we could have continued weakness in the market as the longs continue to bail on their positions,'' said Andrew Lipow, president of Lipow Oil Associates in Houston, Texas.