Crude oil prices rose again yesterday, and prices for gasoline, heating oil and other fuels surged along with them to peaks that apparently guarantee a very expensive winter for consumers.

The Energy Department reported that inventories of oil and fuels increased last week, despite the cutoff of shipments from Iraq and Kuwait, but traders and analysts said the rising prices reflect a widespread belief that shortages are likely by October, when current stocks have been used.

"The stuff that's coming in now was purchased in July or earlier," said John Redpath, an oil expert at Energy Security Analysis Inc. in Washington. "But the market is trading on contracts for October, and it reflects what people believe will be the supply and demand situation that month."

On the New York Mercantile Exchange, crude oil for October delivery closed yesterday at $31.93 a barrel, up 71 cents. The price continued to rise in private trades after the closing bell, according to Platt's Oilgram News.

The November price rose $1.50 -- the maximum permitted by the exchange -- to $30.64. Prices for delivery in every month through April also rose the maximum $1.50.

Gasoline prices are rising even faster. The closing price yesterday was $1.08.55 a gallon, up 4.44 cents from Wednesday. Before this week, unleaded gasoline had never traded for more than $1 a gallon on the New York exchange.

As retail prices continued upward, a senior Justice Department official said yesterday that the department was intensifying its investigation into possible price collusion by the oil companies.

Assistant U.S. Attorney General James Rill said he is calling in top executives of the major oil companies and independent oil marketers "on a one-by-one basis" to explain the reasons for the sharp increases in gasoline prices that followed the Aug. 2 Iraqi invasion of Kuwait.

Heating oil, which has drawn relatively little attention because the start of the heating season is still two months away, closed at just over 96 cents a gallon. A year ago, it was about 51 cents; a month ago, it was 55 cents. Fuel oil dealers acquiring supplies now for the winter season are certain to pass these prices on to their customers, industry analysts said.

The apparent anomaly of rising inventories and simultaneously rising prices is easily explained by the time lag between order and delivery, industry analysts said. The oil and refined products that filled U.S. storage tanks last week were shipped weeks ago, before the Iraqi invasion of Kuwait removed 4.45 million barrels of oil and about 600,000 barrels of gasoline a day from world markets. The prices being paid for oil and gasoline ordered today reflect expectations about the supply situation in the fall.

"The stocks arriving today are ancient history," said Peter Beutel, a trader at Merrill Lynch Energy Futures. Privately held crude oil stocks rose last week to 379.5 million barrels, about 42 million above the level of a year ago, according to the Energy Department, but Beutel said these numbers "have to be kept in perspective." He said the United States refines about 14 million barrels of oil a day, "so if you take all the stocks that they have at the refineries and the crude in the pipelines, that's only about 27 days."

"The refined product situation is actually worse than the crude situation," said Adam Sieminski of Washington Analysis Group. Despite last week's small increase, gasoline stocks are dangerously low, he said, and cannot be made up domestically because U.S. refineries are operating at full capacity.

Saudi Arabia, the world's biggest oil exporter, has pledged to increase its crude oil production by as much as 2 million barrels a day to make up some of the shortfall from Iraq and Kuwait, but apparently it has not yet done so.

Industry experts said that once the Saudi government gives the order to increase production, there still will be a time lag while sales contracts are negotiated, storage facilities are prepared and tankers are ordered.

Atlantic Richfield Co. said yesterday that the surge in spot-market gasoline prices had forced it to scrap the retail price freeze it imposed two weeks ago when all other major oil companies were raising prices in step with the market.

Arco said its sales had increased 19 percent because its prices were lower than its competitors' by as much as 13 cents a gallon. As a result, company officials said, Arco was selling more gasoline than it can refine, so the company was forced to buy gasoline on the wholesale spot market at prices higher than it was getting at the retail pump. George Babikian, president of Arco's refining and marketing division, said the company would increase prices about 2.5 cents a gallon in areas "where Arco prices are well below their competitors."

The American Petroleum Institute, which represents the major oil companies, said last night that "the pump price for gasoline has increased by a considerably smaller amount than have the costs oil companies must pay to replenish those supplies." It said the oil companies "appreciate the patience the public is demonstrating" in the face of the price increases.

Assistant Attorney General Rill said the meetings with oil company executives, which are being held at the Justice Department, are part of an unusually wide-ranging inquiry into allegations of oil industry collusion and other anti-competitive pricing practices that was launched by the antitrust division on Aug. 6.

"We are aggressively pursuing the possibility that that kind of {anti-competitive} conduct might occur," Rill said during a briefing with reporters. Among the areas the antitrust division is "looking at," Rill said, are allegations by independent petroleum marketers that refiners were providing gasoline to company-owned filling stations at prices substantially lower than what they were charging the independents.

He said that the oil companies so far have cooperated with the inquiry.

Staff writer Michael Isikoff contributed to this report.