Updated from 2:50 p.m. EDT

Another day, another record high and another new cause for concern in the energy markets.

The relentless rally in oil prices continued Thursday, with the benchmark crude surpassing both Wednesday's intraday and closing highs as traders shifted their focus to low heating oil supplies ahead of the winter season.

The November futures contract closed 65 cents higher at $52.57 in floor trading on the New York Mercantile Exchange. Prices touched $53 at one point.

In the past five sessions, short-term supply worries have driven crude through $50, $51 and $52 a barrel, the latest record highs in a monthlong surge that had added more than 15% to the price of a barrel of oil. Market watchers now say $60 a barrel is possible, if any new factors disrupt supply and the coming winter season proves to be colder than normal.

Weekly inventory data from the Department of Energy Wednesday showed a smaller-than-expected increase in crude oil and gasoline stockpiles and a decline in distillates, which include such products as home heating oil.

U.S. production is still far from returning to normal after Hurricane Ivan disrupted operations in the Gulf of Mexico three weeks ago. Production is still some 27% below normal and the government has now allowed five companies to borrow from the nation's strategic reserves.

In addition, traders are concerned about exports from Nigeria after a week of civil unrest there and now the possibility of a strike by oil workers.

The developments in the Gulf and Nigeria are just the latest catalysts for a market that's marched steadily higher since late April. Worries about exports from Iraq and Russia have been a major cause of concern. Traders also have built in a so-called terror premium after a series of attacks on oil industry facilities and personnel in Saudi Arabia in the late spring.

A world of worry and unusually strong global demand has kept market sentiment bullish despite efforts by OPEC to keep a lid on prices. Saudi Arabia last Tuesday said it would boost its official production capacity by 1.5 million barrels to 11 million barrels a day.