President Hugo Chavez has set a May 1 deadline for an ambitious plan to wrestle control of several major oil projects from American and European companies.

So a showdown seems inevitable, with officials warning that they might sell American refineries meant to process Venezuelan crude oil.

“Chavez is playing a game of chicken with the largest oil companies in the world,” argues Pietro Pitts, an oil analyst who publishes LatinPetroleum, an industry magazine based here. “And for the moment he is winning.”

According to a Rice University study, 77 percent of the world’s 1.148 trillion barrels of proven reserves is in the hands of national companies; 14 of the top 20 oil-producing companies are state-controlled. The implications are potentially stark for the U.S., which imports 60 percent of its oil.

“We are on a collision course with Chavez over oil,” said Michael Economides, an oil consultant in Houston who wrote an influential essay comparing Chavez’s populist appeal in Latin America with the pan-Arabism of Col. Moammar Gadhafi of Libya two decades ago. “Chavez poses a much bigger threat to America’s energy security than Saddam Hussein ever did.”