As economic growth slows across the industrial world, the future price of oil becomes a fierce tug of war between nations that export and import the precious fuel.
A dip in world economic activity, experts say, could reduce global demand for oil by a million barrels a day or more.
Theoretically, at least, this should exert downward pressure on the price of oil -- unless producers, centered in the 13-member Organization of Petroleum Exporting Countries (OPEC), reduce output to match.
This year, the Organization for Economic Cooperation and Development (OECD) reports, economic growth among 24 industrial powers of the noncommunist world may average only 1 percent, down from 3.25 percent in 1979.
OECD experts predict an actual recession in the United States and Britain, plus slower growth rates for Japan, West Germany, France, Italy, and some other powers.
Such predictions do not seem to trouble OPEC oil exporters, almost all of whom in the last month have sharply raised the official price of their oil, with several -- including Libya, Nigeria, Algeria, and Mexico -- now topping $30 a barrel or more.
Nor are price hikes confined to OPEC members. British officials indicate that the cost of their north Sea oil -- comparable in quality to the prized North African crudes -- may jump above $30 a barrel, including surcharges.
Britain, norway, Canada, and other non- OPEC producers usually align the price of their oil, depending on quality and distance from markets, on OPEC standards.
Nonetheless, spot-market prices for oil are softening, from$45 a barrel a few weeks ago to the high $30s now, as demand lessens in relation to supply.
As late as 1978, according to the US Department of Energy (DOE), only 5 percent of OPEC oil was sold in the spot market -- that is , above contract, or official, prices.
By September 1979, this spot-market share had moved up to 15 percent and, during the last frenzied quarter of the year, to 20 or 25 percent.
Now, according to Gary Ross of the Petroleum Industry Research Foundation Inc., the spot-market share has begun to decline, as oil-importing nations top off their storage tanks at brimful.
In two ways, Dr. Ross says, OPEC producers are trying to keep the price jacked up:
* Many OPEC producers now sell less oil to their longtime oil company contractors, reserving more crude for straight government- to-government deals.
* Some OPEC members require their oil company customers to buy a percentage of their oil at what are called "market premiums" or "bonus or access to contract crude," Dr. Ross says.
To obtain contracts for future deliveries of crude, in other words, firms may be required to pay for some of their oil in the "gray area" above contract prices.
Because the world economy is slowing, experts say, Western nations could absorb without hardship a drop in OPEC oil production from last year's 31 million barrels a day to 30 million, or possibly even 29 million barrels.
Still untested is whether the carterl as a whole will shrink output below that figure, in an effort to maintain high prices. Here the balance wheel is Saudi Arabia, OPEC's largest producer, now pumping 9.5 million barrels a day. Saudi officials want to keep world oil output high enough to prevent the Western industrial powers from slipping into a deep recession.