Rhetoric is becoming reality in Venezuela, and the world oil market could change as a result.

Two oil giants, ExxonMobil and ConocoPhillips, did not reach agreements with Venezuela on ceding their majority stakes in projects in the country before a government deadline of Tuesday.  The government will take over control of their projects in the prized Orinoco Belt, south of Caracas

Four other oil companies, BP, Chevron, Total of France and Statoil of Norway agreed to the reduced terms of doing business in Venezuela.

For ConocoPhillips in particular, a forced exit from Venezuela would be a severe blow: the country accounted for 4 percent of its worldwide production.

The company said on Tuesday that negotiations with the government were continuing, but that it would take an impairment charge of $4.5 billion on its projects in Venezuela.

A member of OPEC, Venezuela is one of the biggest oil exporters to the United States. The country has proven reserves of at least 80 billion barrels, but some experts say that the Orinoco Belt fields could give it the largest reserves of any nation in the world.

The question is whether the state-run Venezuelan oil company has the expertise and resources to develop those fields to their full potential.

Venezuela's president, Hugo Chavez, has portrayed his campaign against foreign energy companies as one of closing an inequality gap and promoting the national interest.

"Everything that was privatized will be nationalized," he declared in January, a pledge that has rattled foreign investors.

More important, the new rules that Chavez is handing down could serve as a template by other countries in their negotiations with American and European oil giants.

 "What happens in Venezuela is something the Russians will look at, and may have bearing on places like Iran, Nigeria and other countries," Amy Myers Jaffe, an oil analyst at Rice University told the New York Times.