NEW YORK - The economies of many big oil-exporting countries are growing so fast that their need for energy within their borders is crimping how much they can sell abroad, adding new strains to the global oil market.
Analysts say the sharp growth, if it continues, means several of the world's most important suppliers may need to start importing oil within a decade to power all the new cars, houses, and businesses they are buying and creating with their oil wealth.
Indonesia has already made this flip. By some projections, the same thing could happen within five years to Mexico, the number two source of foreign oil for the United States, and soon after that to Iran, the world's fourth-largest exporter.
In some cases, the governments of these countries subsidize gasoline heavily for their citizens, selling it for as little as 7 cents a gallon, a practice that industry analysts say fosters wasteful habits.
"It is a very serious threat that a lot of major exporters that we count on today for international oil supply are no longer going to be net exporters any more in five to 10 years," said Amy Myers Jaffe, an oil analyst at Rice University.
The trend, though increasingly important, does not necessarily mean there will be oil shortages.
More likely, analysts say, it will mean big market shifts, with the number of exporting countries shrinking and unconventional sources like Canadian tar sands becoming more important, especially for the United States.
And there is likely to be more pressure to open areas now closed to oil production.
Greater political stability and increased drilling in some important oil states, notably Iraq, Iran, and Venezuela, could help offset the rising demand from other oil exporters.
"Ten years from now, world capacity to produce oil could be 20 percent higher than today," said Daniel Yergin, chairman of Cambridge Energy Research Associates. "But a lot will depend on how the geopolitics work out."
Rising internal demand may offset 40 percent of the increase in Saudi oil production between now and 2010, while more than half the projected decline in Iranian exports will be caused by internal consumption, said a recent report by CIBC World Markets.
The report said "soaring internal rates of oil consumption" in Russia, in Mexico, and in member states of the Organization of the Petroleum Exporting Countries would reduce crude exports as much as 2.5 million barrels a day by the end of the decade.
That is about 3 percent of global oil demand.
It may not sound high, but analysts say demand for oil is so inflexible, and the world has so little spare production capacity, that even small shortfalls can raise prices.
In 2002, when a labor strike in Venezuela took 3 percent of global production off line, oil prices spiked 26 percent within weeks.
Growth in demand among oil exporters is one aspect of a larger issue, breakneck economic growth in parts of the developing world.
China and India are expected to account for much of the increase in global oil demand in the next 20 years.
But Fatih Birol, chief economist at the International Energy Agency in Paris, rated consumption growth among oil exporters as the second-biggest threat to meeting the world's oil needs.
"It's a big problem, and growing all the time," Birol said.
