At the same time, oil consumption keeps expanding. Global consumption is forecast to increase by 1.2 million barrels a day this year, to 87.2 million barrels a day, with much of the growth in demand coming from China, India and the Middle East, according to the International Energy Agency, a group that advises industrialized countries.

In the United States and through much of the developed world, the higher fuel prices have led drivers to reduce their consumption, and gasoline demand is expected to drop this year. But that drop will be more than offset by the rise in energy demand from developing countries. In the next two decades, demand is projected to jump by 35 percent, and developing countries will consume more oil than industrialized countries.

Higher oil prices mean record profits for oil companies that have, to some extent, masked the supply problems. Exxon Mobil and Chevron are both expected to deliver knockout performances when reporting quarterly earnings this week, even as they struggle to increase production.

“What is disturbing here is that things seem to get worse, not better,” said David Greely, an analyst at Goldman Sachs. “These high prices are not attracting meaningful new supplies.”

The outlook for oil supplies “signals a period of unprecedented scarcity,” Jeff Rubin, an analyst at CIBC World Markets, said last week. Oil prices might exceed $200 a barrel by 2012, he said, a level that would very likely mean $7-a-gallon gasoline in the United States.

Some regions are simply running out of reserves. Norway’s production has slumped by 25 percent since its peak in 2001, and in Britain, output has dropped 43 percent in eight years. Production from the giant Prudhoe Bay field in Alaska has dropped by 65 percent from its peak two decades ago.

In many other places, the problems are not below ground, as energy executives like to put it, but above ground. Higher petroleum taxes and more costly licensing agreements, a scarcity of workers and swelling costs, as well as political wrangling and violence, are making it harder to raise production.