The bidding process was first conceived last year when oil prices were higher but Petróleos de Venezuela’s production decline was getting impossible to overlook. Still, the process is moving into high gear only this month, with the authorities here expected to start reviewing the companies’ bidding plans on new areas of the Orinoco Belt, an area in southern Venezuela with an estimated 235 billion barrels of recoverable oil. Altogether, more than $20 billion in investment could be required to assemble devilishly complex projects capable of producing a combined 1.2 million barrels of oil a day.

Mr. Chávez’s olive branch to Western oil companies comes after he nationalized their oil fields in 2007. Two companies, Exxon Mobil and ConocoPhillips, left Venezuela and are still waging legal battles over lost projects.

But Venezuela may have little choice but to form new ventures with foreign oil companies. Nationalizations in other sectors, like agriculture and steel manufacturing, are fueling capital flight, leaving Venezuela reliant on oil for about 93 percent of its export revenue in 2008, up from 69 percent in 1998 when Mr. Chávez was first elected.

In the past year, with higher oil prices paving the way, Mr. Chávez also vastly expanded Petróleos de Venezuela’s power, inextricably linking it to his political program. He directed the oil company to build roads, import and distribute food, build docks and shipyards and set up a light-bulb factory. He even expanded it into areas like milk production, soybean farming and the training of athletes after a weak performance at the Beijing Olympics.

One of the oil company’s ventures sells subsidized food and extols Mr. Chávez’s leadership at its stores across Venezuela. At one frenzied store in eastern Caracas, posters hung from the ceiling last Saturday showing Mr. Chávez arm in arm with children beneath the heading, “fortifying agrarian socialism.”

Petróleos de Venezuela has also carried out nationalizations in other industries, absorbing companies like Electricidad de Caracas, the utility serving this city of five million. Top executives like Eulogio del Pino, the Stanford-educated vice president for exploration and production, spent much of 2008 negotiating unfinished deals like the takeover of a cement company.