Is Saudi Arabia collecting a vast financial windfall from high oil prices at the expense of consumers in the United States and other countries whose troops are protecting the desert kingdom?

It is, according to House Majority Leader Richard A. Gephardt (D-Mo.), who said last week the Saudis will collect $43 billion in extra revenue over 12 months and "literally could pay for {Operation} Desert Shield themselves."

Not so, respond the Saudis. They say the billions of dollars they have gained through increased oil production at higher prices since Iraq invaded Kuwait Aug. 2 have been offset by additional expenses for weapons, foreign aid and fuel and support services for the military forces deployed to confront Iraq.

In a letter yesterday to House Armed Services Committee Chairman Les Aspin (D-Wis.), Saudi Ambassador Bandar bin Sultan said his country will earn an extra $13 billion in its current fiscal year as a result of higher prices and increased production but "additional Saudi costs as a consequence of the {Persian Gulf} crisis will more than take" the additional revenue.

Independent analysts tend to agree with him.

In the five months since Iraq invaded Kuwait and the United Nations boycotted oil from the two countries, higher oil prices have caused a huge transfer of wealth from consumers to oil producers.

In the second half of 1990, the 11 members of the Organization of Petroleum Exporting Countries (OPEC) other than Iraq and Kuwait took in $31.8 billion more than they would have without the increases, according to calculations by Cambridge Energy Research Associates. Non-OPEC producers such as Mexico, Britain and Norway also have recorded large revenue gains.

The United States, which recently has been importing about 4.5 million barrels daily, has shelled out the most additional cash. According to the World Bank, however, the "most severely affected" countries are 41 poor nations of Eastern Europe, Africa and South Asia. They not only are paying more for their oil but also, when Kuwait and Iraq were shut down, lost export markets and remittances sent home by expatriate nationals who were working in the two countries.

Oil surged from about $20 a barrel before the invasion to more than $40 in early September, but recently has settled at about $27. During that time Saudi Arabia, by far the world's biggest oil exporter, increased its production from about 5.5 million barrels a day to more than 8 million.

Peter Bogin, assistant director for oil markets at the Paris office of Cambridge Energy Research Associates, has calculated that Saudi Arabia took in $9.8 billion more in 1990 than it would have without the price increases.

Assuming Bogin's figure is correct, the $9.8 billion in extra income Saudi Arabia collected in a five-month period when prices peaked and then fell would exceed Bandar's estimates, on an annual basis, but fall far short of the $43 billion projection over 12 months used by Gephardt and Rep. Charles E. Schumer (D-N.Y.) in urging a greater Saudi contribution to Desert Shield.

The $43 billion figure was derived from simple multiplication of Saudi Arabia's export figures by the most commonly quoted price.

But according to Bogin and other analysts, there are several reasons Saudi Arabia is making less of a killing than it might appear.

Much of the oil exported by Saudi Arabia is "heavy" or "sour" crude, which commands a lower price. In September, as the price of light, sweet crude surged toward $40 a barrel in trading on the New York Mercantile Exchange, the average price of Saudi heavy crude on the cash market was $28.30, according to the latest OPEC Bulletin.

Saudi Arabia is paid in U.S. dollars for almost all the oil it exports. With the dollar commanding its lowest value in years against other major currencies, the Saudis in effect are giving a discount to buyers in Europe and Japan -- their biggest customers -- and reducing their own purchasing power.

Some of Saudi Arabia's exports generate little, if any, revenue because the oil is virtually given away to Turkey, Bangladesh, Pakistan and other Moslem countries that cannot afford to buy it.

But the biggest factor, according to J. Robinson West, president of the Washington-based Petroleum Finance Co., is that Saudi Arabia has taken on "enormous offsetting commitments" that soak up most of the money. Fareed Mohamedi, an analyst with West's firm, calculated that the Saudis actually spent more dollars than they took in last year despite the increased oil revenue.

Bandar gave these figures for his country's additional expenses: $3.65 billion in aid to nations such as Egypt and Syria that have participated in the Desert Shield deployment; $3 billion for "U.S. support" in the operation; $12.6 billion for arms purchases from the United States and other countries; and $4 billion for new facilities to increase oil output.