The first well in the Carabobo field of Venezuela's oil-rich Orinoco Belt began pumping extra-heavy crude after a launch ceremony attended by the country's energy minister and the CEO of Spain's Repsol, a partner in the project.

Energy Minister Rafael Ramirez, who is also head of state oil giant PDVSA, and Repsol chief Antonio Brufau inaugurated production at Carabobo, the Spanish company said.

The well is projected to reach a maximum output of 400,000 barrels per day and plans call for the construction of a refinery nearby.

Operational control rests with Petrocarabobo, which is 60-percent held by PDVSA. Repsol, with a stake of 11 percent, is one of five partners.

"Part of the heavy crude from this project will be destined for Repsol's Spanish refineries," the company said.

Brufau and Ramirez also reviewed plans for the development of the massive Perla gas field in northwestern Venezuela, a reserve of roughly 3 billion barrels of oil equivalent, Repsol said.

The Spanish company discovered the gas in 2009 and development work began in late 2011.

President Hugo Chavez took the opportunity of a visit to Caracas by Brufau in August to stress the friendship between Venezuela and Repsol.

PDVSA calculates that only around 20 percent - some 300 billion barrels - of the estimated reserves in the Orinoco Belt can be extracted on commercially viable terms, but energy experts in the U.S. government suggest an extraction rate of 40 percent is possible. EFE