Updated from 2:35 p.m.

Crude oil prices closed lower Thursday, falling below the $47-a-barrel level again, amid a deep November slump.

The December futures contract shed 62 cents to $46.22 in Nymex floor trading, near a new two-month low. The benchmark U.S. crude remains some 17% below its October record high of $55.17.

Prices got a rare boost Wednesday, after weekly inventory data showed another decline in heating oil, reviving market worries about supply ahead of the winter season.

Prices first hit a two-month low earlier this week. U.S. production has been steadily returning to normal, following widespread disruptions to operations in the Gulf of Mexico because of Hurricane Ivan in September.

Until the recent correction, prices touched records on a regular basis as traders worried about a variety of factors affecting short-term supply.

Attacks on Iraq's oil infrastructure -- including the most recent one Sunday -- have caused periodic production problems of varying consequence there. Threats to production in Norway, Russia, Venezuela and Nigeria also have been a factor.