LONDON — For decades the world's major oil companies and their engineering experts have been eyeing the Arctic region and wondering how to get at the oil and gas deposits that are said to lie, in almost legendary quantities, beneath the vast expanses of ice. With the price of crude oil now well above $100, has their moment at last arrived?

Two factors suggest that this may be the case. First, as long as world oil markets were dominated by cheap Mideast oil that could be easily extracted from the open deserts, there was almost no chance of competition from other regions.

But that era that passed. No one believes that oil will ever again be the cheap and plentiful commodity it once was. Even if the largest reserves remain in the Middle East, the whole region is now a caldron of turbulence.