Buried deep in Siberia's frozen vastness is a vast trove of what the Russians call "blue gold," a quantity of natural gas that is yet to be fully measured but already assures the Soviet Union a place in the future as one of the world's biggest energy producers, perhaps even the largest of all.

Over the past decade, important gas deposits have been surveyed for the first time in a number of regions around the country - the eastern Ukraine, Soviet Central Asia and the Orenburg region, among others. Probably the most substantial reserves, though, are located in the Tyumen Province of western Siberia and here in Yakutia, where detailed geological work is just beginning.

The Soviet Union's enormous wealth in gas and oil looms as a major coming factor on the international economic scene, particularly in view of the West's serious shortages and the difficulties in securing guaranteed supplies from Arab countries and Third World producers. Ironically, if the West is to tap Soviet energy reserves, it will have to supply the technology. Energy is a major hard-currency earner for Mosco and becomes more profitable every year.Overall, the Soviets are thought to have made about $6 billion last year on sales of oil to the West - rouhgly half of Moscow's total exports to those countries - and the price for all customers, including other Communists, is steadily rising.

Until recently, however, the Soviets were net importers of natural gas, supplementing their own resources with purchases from Iran and Afghanistan. Soviet output is now-soaring and is expected to be nearly 10 times as much in 1980 as it was in early 1960s. Exports are to more than triple before the end of the decade, with West Germany, Italy, Austria and France buying significant amoutns.

Moscow appears to have finally solved the problem of extracting and transporting gas from the rich Orenburg fields in the southern Urals on the edge of Siberia. A 2,000-mile pipeline under construction by the Kremlin and its Eastern European allies will effectively double Soviet supplies to those countries - a vital element in their economies and, equally important, a symbol of political interdependence.

The rest of Siberia represents the great remaining challenge. The far northern reaches of Tyumen, straddling the Arctic Circle, are thought to have as much as three-fourths of the country's potential gas reserves, a figure so colossal that about 85 per cent of increased production in the next few years is scheduled to come from those as yet little-cultivated fields.

The problem is that nature provided a formidable defense for its resources in the isolation and permafrost of the territory. To succeed in pumping out and delivering the gas - indeed to find out just how much there really is - Moscow has been looking for help from technologically advanced Western countries, including the United States.

What the Soviets want and have thus far managed by and large to get is equipment such as wide-diameter steel pipes, compressors and drilling apparatus from Western companies, to be repaid over the long term, stretching even beyond the end of the century, in natural gas output.Some pipelines already exist, accounting for deliveries measured in billions of cubic feet to France and West Germany.

One of the biggest projects, code-named North Star, involves several large American companies - Tenneco, Brown and Root and Texas Eastern - that would build a pipeline from northern Tyumen to Murmansk. Although the port is above the Arctic Circle, it is usable all year round because it is at the tail end of the Gulf Stream.

Special tankers there would ferry the liquefied gas to the United States and possibly other Western buyers. The deal, if it ever comes off, would be worth about $8 billion.

Negotiations began in the first flush of Soviet-American detente, now nearly five years ago, but floundered in 1974 when Congress blocked the use of any U.S. government-backed loans for Soviet energy projects. Without that assured official financial backing, real headway seemed impossible, but the American companies are once again talking to the Russians, and business sources in Moscow say there is a good chance of getting startup funds from commercial banks in the United States and Europe.

A precedent for progress has been set here in Yakutia. Preliminary exploration in the remote Vilyuy basin has shown substantial fields, and American companies - Occidental Petroleum and El Paso Gas - joined by Japanese companies were prepared to go ahead with a major extraction and shipping plan when the congressional ban on government energy credits upset the deal.

Then last spring, with $50 million from a consortium of American banks and the Japanese Export-Import Bank, matched by $50 million in hard currency from the Soviets, a contract for essential further exploration was signed, the first step in fulfilling the ambitious early plan. That work is now getting under way.

Specialists at the Permafrost Institute in Yakutsk, which is the administrative center for this area, say that once the "quantitative and qualitative analyses" are completed, a pipeline stretching about 2,000 miles to the Vladivostok area of the Soviet Far East could be built in five years. The project also calls for a gas liquefaction plant at the port and a fleet of special tankers to transport the fuel.

Eventually 2 billion cubic feet a day of the gas would be sent to the U.S. West Coast and Japan over a 25-year period in repayment for what would be an outlay of about $4 billion by American and Japanese companies. Financing of so huge an investment is clearly a major undertaking, but Western specialists in Moscow are optimistic.

American involvement in developing Soviet energy resources is a tricky business with considerable political significance. Although the amount of gas involved in the Yakutia project represents less than 1 per cent of the total consumed in the United States, the idea of any dependence on the Soviet Union for so sensitive a commodity is bound to be controversial.

But as the great natural gas shortage of the past winner in the United States showed, coming to terms with the Soviets on the Siberian reserves may some day be a necessity.