Goldman Sachs cut its 2012 Brent crude forecast to $120 a barrel from $130 a barrel, joining a growing chorus of increasingly bearish analysts.
Stock markets, the euro and base metals have tumbled this week on mounting worries the debt crisis in Greece will unleash a global recession. Brent may come under further pressure as Libyan output may get restored faster than expected.
"The market continues to focus on the risk of a new economic recession, triggered by the stress on the European financial and banking system," Goldman Sachs analysts said, noting that the financial stress in Europe will continue to present headwinds to economic and oil demand growth next year.
Concern about Greece's ability to avert a default as negotiations about a second bailout inched ahead spooked equity markets after the country admitted it would miss its deficit targets.
"I think more people are getting more afraid," said Tony Nunan, a Tokyo-based risk manager at Mitsubishi Corp.
"There's a concern that there will be a mini-financial crisis. If they don't do it properly, it will cause some banks in Europe to fail, and there will be a domino effect," he said, referring to European leaders' efforts to resolve Greece's financial crisis.
The deepening crisis has forced investors to seek safe havens such as gold and Treasuries, which has helped push the US dollar to its highest in more than eight months against a basket of major currencies.
A stronger dollar can pressure dollar-denominated commodities prices by making them more expensive to consumers using other currencies.
Brent crude for November delivery fell by 73 cents to $100.98 by 0925 GMT, after hitting an intraday low of $100.42 a barrel, which was within striking distance of an eight-week low.
US crude fell $1.22 cents to $76.39 a barrel after reaching an intraday low of $75.92.
OPEC EYES PRICES, LIBYA TURNING TAP ON
Qatar did not see a need for oil cartel OPEC to meet before its next scheduled gathering in December, although it is closely watching the impact on oil demand of slowing economic growth and the debt crisis in Europe, Energy Minister Mohammed al-Sada told reporters in Tokyo.
Libya will start pumping crude at two major oilfields in about two weeks, doubling production to 700,000 barrels a day by year-end, the country's head of National Oil Corp Nouri Berouin said in an interview with Reuters.
While the resumption in operations at Repsol-operated Sharara field and Eni part-owned Elephant will help boost output, Berouin said Libya's biggest oil terminal at Es-Sider may take more than a year to be fully repaired.
US commercial crude stockpiles are expected to have risen for a second week as imports continued to increase, a preliminary Reuters poll of analysts found on Monday.
Industry group the American Petroleum Institute will release its weekly inventory report at 2030 GMT. The Energy Information Administration will issue its own stocks data on Wednesday.
Copyright Reuters, 2011