The six-week surge in crude oil prices halted abruptly yesterday after President Bush dispatched U.S. troops to protect the oil fields of Saudi Arabia, but analysts cautioned that uncertainties about supply could push prices up throughout next winter.

Oil supplies are plentiful throughout the world, they said, and several countries are expected to increase their output to make up for the halt in exports from Iraq and Kuwait. But the gap between supply and demand could still exceed 1 million barrels a day when today's bulging inventories have been used, industry experts agreed.

In his televised address to the nation yesterday morning, Bush said U.S. troops would defend "Saudi Arabia and other friends in the Persian Gulf," presumably including the United Arab Emirates, another key Arab producer facing threats from Iraq. The president said he will "ask producing nations to do what they can to increase production in order to minimize any impact" on the world economy caused by the embargo. In addition, Bush urged domestic refiners to exercise restraint in raising gasoline prices. {Details on Page E1.}

Crude oil prices on the London spot market had already begun to fall in anticipation of Bush's announcement. In New York, the price of a benchmark barrel for September delivery fell $2.35, to $25.96. On June 20, it was below $18. Some wholesale prices of refined products also declined.

The stock market rallied after six straight days of losses since Iraq invaded Kuwait. The Dow Jones industrial average, which flirted with the 3000 level last month, rose 24.26 points to close at 2734.90. {Details on Page E2.}

Oil traders and industry analysts said there are so many variables in the world oil supply picture that projections beyond a very short horizon have little value.

One of the unknowns is the effectiveness of the United Nations-ordered boycott of crude oil and refined products from Iraq and Kuwait. Some analysts assume that opportunistic traders and consuming countries willing to defy the embargo will find discounts on that oil attractive enough to risk bringing it to market, as happened in previous boycotts of oil from Iran and Libya.

Worldwide oil production outside communist countries is about 54 million barrels a day. Each barrel contains 42 gallons. A complete loss of Iraqi and Kuwaiti production would take 4 million to 5 million barrels a day off the market. Other producing countries have the capacity to deliver about 2.5 million barrels a day beyond their current output, analysts said. By accelerating maintenance schedules in Alaska and the North Sea, producers might increase daily output by 500,000 barrels.

That would leave a gap of at least 1 million barrels a day to be made up from national stockpiles such as the U.S. Strategic Petroleum Reserve, or through conservation, new discoveries, conversion of major industries to natural gas and additions to capacity in countries with extensive reserves, such as Saudi Arabia.

The Saudis are believed to be able to increase their daily output by as much as 2 million barrels a day, or more than 40 percent. They have made no public commitment to do so, but it is widely assumed in the industry that they will.

Energy Department officials and sources within Aramco, a state-owned Saudi oil company, said they could not confirm published reports of a Saudi promise to deliver an additional 2 million barrels a day. But oil industry analysts said the reports were widely believed and partly caused yesterday's price drop.

"I told my clients it's a done deal," said Vahan Zanoyan, a Washington-based OPEC-watcher at Petroleum Finance Co. "By inviting the United States to send troops, Saudi Arabia has taken clear, unambiguous sides against Iraq. Raising output to stabilize the market is their share."

"There's no doubt there's an agreement, but don't look for any formal announcement," an Aramco official said. "There's no sense waving a red flag at the bull in the neighborhood," he said, referring to Iraqi President Saddam Hussein.

But others were less sure of Saudi Arabia's intentions.

Lawrence J. Goldstein, vice president of the Petroleum Industry Research Foundation, said there was only "a much higher probability today ... than 48 hours ago." Philip K. Verleger, an oil expert at the Institute for International Economics, said that "everybody thinks the Saudis are going to produce another 2 million a day, but a source I trust says it isn't certain at all."

Mexican Foreign Minister Fernando Solana said in Washington that his country would increase its output by 100,000 barrels a day. Venezuela said it would add 500,000. No other country can match the capacity of Saudi Arabia and Venezuela, but analysts said Indonesia, Gabon, Qatar, Ecuador and Norway could contribute.

A report by Cambridge Energy Research Associates said some temporary market disruptions are inevitable even if crude supply and demand are in balance because new tanker routes must be devised and refineries that rely on Iraqi or Kuwaiti oil may have to be modified.

One element that was virtually absent from yesterday's analyses was the role of the Organization of Petroleum Exporting Countries. Only two weeks ago, under Iraqi pressure, OPEC members -- including Saudi Arabia, Kuwait and Venezuela -- accepted new production limits in an effort to drive up prices. Now, as a result of Saddam's escalation from threats to force, OPEC discipline has been eliminated from the price equation.

OPEC President Sadek Boussena, the Algerian oil minister, urged members to "preserve OPEC unity." Iranian Petroleum Minister Gholamreza Aghazadeh, in a statement released by the OPEC news agency, said members should "exercise self-control," but he also said that "if ever a shortage was imminent in the international market, the OPEC states should take the necessary decisions."