Oil prices slumped more than 5 percent on Monday after an influential Wall Street bank cut its forecasts and Gulf producers showed no sign of being willing to curb output.
Brent was down $2.36 to $47.75 a barrel by 1:44 p.m. EST (1644 GMT), after dropping to $47.16, its lowest since April 2009.
U.S. crude was down $2.07 at $46.30 after earlier hitting $45.90, also near a six-year low.
Three days of relative price stability ended abruptly after Goldman Sachs slashed its outlook, saying oil could tumble to the low $40s.
“I figured we’d see $40 in the near term, but everything seems to be happening quicker than expected,” Tariq Zahir of Tyche Capital Advisors.
Goldman said that despite declining investments in U.S. shale oil, production will take longer to fall. The bank cut its three-month forecasts for Brent to $42 a barrel from $80 and for the U.S. futures contract to $41 from $70.
The unrelenting rout that has wiped nearly 60 percent off prices since June shows no sign of letting up, with many traders giving up attempts to predict a bottom even amid growing signs that U.S. shale drillers are hitting the brakes.
The number of rigs drilling for oil in North Dakota fell by eight to their lowest since 2010.
An unusual spate of major refinery glitches across the U.S. East and Midwest added to the concerns, threatening to accelerate a build-up of surplus crude supplies.
Four U.S. refineries with a combined refining capacity of more than a million barrels per day were recovering from disruptions at the weekend caused by either cold weather or unexplained fires. Three were restarting on Monday, while the fourth in Lima, Ohio, was expected to be offline for a week.
“So not only do you have the macro influences on world crude prices, but now you have some refinery outages, so that will put some pressure on U.S. crude,” said Richard Hastings, macro strategist at Global Hunter Securities.
“We do now believe that there are risks of deeper breakdowns,” possibly below $40, he said.
As OPEC’s November decision not to curtail production in the face of falling prices piles pressure on some group members, Venezuelan President Nicolas Maduro met Saudi Arabia’s Crown Prince Salman in Riyadh on Sunday as part of a diplomatic tour in the Gulf to discuss falling oil prices.
However, Saudi Arabia, the world’s biggest oil exporter, has said it will not support prices by cutting production and ignored calls from smaller OPEC members, including Venezuela, to react to falling oil prices at the cartel’s November meeting.
On Saturday, Iran vowed to help Venezuela stem the oil price fall.