Washington — Oil prices may decline somewhat - or at least remain stable - if energy conservation efforts continue and if the stability of the Persian Gulf does not further erode.
Oil prices in the future, in other words, depends on a variety of factors, some of which extend beyond the current crisis within OPEC, the oil-producing cartel.
First, a good deal of permanent conservation has been built into the US economic system since the oil price explosion of the 1970s.
''Today, we are burning 15 to 20 percent less oil than we did in 1979, when the level of economic activity was about the same as it is now,'' says Charles J. DiBona, president of the American Petroleum Institute.
Early in 1979, he says, Americans burned 21 million barrels per day (b.p.d.) of oil. Consumption today, according to the Department of Energy is just over 15 million b.p.d.
''When the oil crisis began in 1973, the estimate was that by 1990 US oil consumption would push 40 million b.p.d. With hindsight, that looks ridiculous. The US now uses about as much oil as it did in 1970,'' says Mr. DiBona.
But what happens when the recession ends and American factories, currently operating at 68 percent capacity, need more fuel? Suppose oil prices drop to $25 a barrel?
Gasoline prices, in that event would drop. So would the cost of home heating oil. This would not necessarily erase conservation gains.
''Three quarters of the conservation we have achieved,'' DiBona says, ''is price-induced. About one quarter is income induced,'' or due to recession.
Does that imply that if oil prices plummet and prosperity returns, Americans might forget lessons so painfully learned, push up their thermostats, and gun new gas guzzlers down the road? Experts doubt it.
''There will be some increase in consumption,'' say DiBona, ''but not anywhere near the old level.''
Neither homeowners nor plant managers will tear out heat pumps, insulation, and a myriad other energy saving measures simply because oil becomes cheaper. Millions of homes and many factories switched from burning oil to natural gas.
Nor will most Americans rush back to big cars. United States automakers are spending billions of dollars to develop small cars, says Ford Motor Company chaiman Philip Caldwell. They will not and cannot easily reverse that trend.
Western Europe and Japan also have become more efficient in their use of energy. All told, the noncommunist world's demand for oil dropped from 52 million b.p.d. in 1979 to 46 milllion b.p.d. in 1982. Consumption this year is expected to be about the same.
The 13 members of the Organization of Petroleum Exporting Countries, meanwhile - which produced 31 million b.p.d. in 1979 - now are down to 18 million barrels daily or less.
OPEC's share of world oil production has dropped partly because of lower demand, but also because non-OPEC producers - notably Mexico, Britain, and Norway in the North Sea as well as Alaska, have boosted their output. The Soviet Union also continues to be a net exporter of oil to noncommunist nations - a bit more than 2 million b.p.d.
All these factors result in what is called the oil glut. The noncommunist world now has an unused production capacity equal to 10 million b.p.d. Saudi Arabia alone has reduced its output from 10 million b.p.d. in 1981 to little more than 4 million b.p.d. now.
Almost all of this surplus capacity, experts stress, lies in the Middle East, mainly in the Persian Gulf area - Saudi Arabia, Kuwait, and other Gulf sheikdoms , Iran, and Iraq.
Stability in the Middle East is critical. Any crisis that closed the Persian Gulf to oil exports - for example, a war between Iran and Saudi Arabia - would transform the world oil picture overnight. Even a partial shutdown could cause oil prices to climb.
In several ways the United States has done much to reduce American vulnerability to Middle East cutoffs.
The US now imports only 32 percent of the oil it burns, compared with more than 45 percent in 1979.
The share of imports from Arab wells has declined sharply from 40 percent of all imported oil late in 1981 to 18 percent now. Saudi Arabia, long the No. 1 foreign oil supplier to the US, now ranks behind Mexico, Britain, and Venezuela.
Finally, the US has 280 million barrels of oil stored in salt domes in Texas and Louisiana - the Strategic Petroleum Reserve - and more is added daily.