By Dan Molinski
Of DOW JONES NEWSWIRES

CARACAS (Dow Jones)--Final registration has ended for Venezuela's Carabobo oil-drilling auction, bringing the long-delayed bidding that's set for next week a crucial step closer.

The Carabobo auction is for the most-touted oil drilling project in this petroleum-rich South American nation since the 1990s, when Venezuela invited global oil majors to take part in its hydrocarbon sector under the Apertura, or "Opening" program.

President Hugo Chavez vowed to bring an end to that "Opening" during his victorious election campaign in 1998, claiming the deals signed with foreign oil firms "ran counter to the national interest."

Fast-forward to 2010, and the Chavez government now needs new foreign investment in its oil sector. The plan seems to fly in the face of Chavez' continuous nationalizations of other parts of his economy, from the cement and coffee industries to mining and even some areas of the oil sector.

But Chavez has little choice when it comes to oil production, the country's main source of revenue. Western fields around Lake Maracaibo that for decades gave Venezuela the bulk of its production are now maturing, meaning they produce less than they used to.

And the new, untapped fields in the eastern Orinoco region where the Carabobo blocks are located mostly contain extra-heavy, tar-like crude that requires experience, know-how and deep pockets to extract. Only foreign firms can provide all those needs.

The Monday registration deadline for consortiums or individual companies planning to make a bid on Jan. 28 has closed, a high-level official in the Oil Ministry confirmed Tuesday. "All the interested consortiums completed the registration, with one exception that was lacking a certain requirement," said the official, who asked not to be named. The official didn't provide details.

A source familiar with the process said one of the consortiums that registered includes Chevron (CVX), Mitsubishi and other Japanese firms. A Mitsubishi official who asked not to be identified would not confirm any consortium plan with Chevron or others, but did say Tuesday that the company "is very interested in Carabobo."

Chevron officials were unavailable to comment.

The results of the Carabobo auction are expected to be announced Feb. 10.

The bidding is for seven oil blocks where vast reserves have been discovered and verified. The government hopes drilling in the Carabobo fields will lift Venezuelan oil production by 1.2 million barrels a day by 2014, which could put the country's total production well above 4 million barrels a day, according to government estimates.

Venezuela says it currently produces around 3 million barrels a day, though independent estimates dispute that, and calculate output of as low as 2.2 million barrels a day.

Total investments in the Carabobo project, which could include the building of upgraders to improve the quality of the tar-like crude, would reach into the tens of billions of dollars.

Winning bidders would form a joint-venture partnership with state oil firm Petroleos de Venezuela SA, or PDVSA. The bidding firms would get a 40% stake to PDVSA's 60% stake.

If the auction is successful, it could help rescue the country's flagging oil-production levels and lead to much-needed growth for an economy mired in recession amid lower global oil prices.

Oil accounts for more than one-third of Venezuela's gross domestic product, more than half of government revenue and about nine-tenths of the country's exports.

The Carabobo auction was supposed to take place nearly a year ago, but lower oil prices sapped some interest in the project, leading the government and oil companies to seek new common ground on issues such as taxes and royalties.

It wasn't immediately clear what other companies may have registered and whether all would be consortiums, or if some firms would bid solo.

Companies that in recent months have shown interest in making a bid include China National Petroleum Corp., or CNPC, France's Total SA (TOT, FP.FR) Spain's Repsol YPF SA (REP, REP.MC), Royal Dutch Shell PLC (RDSA, RDSA.LN) and India's Oil & Natural Gas Corp., or ONGC (500312.BY).

Analysts say many foreign oil firms are willing to overlook the many political or operational risks related to dealing with Chavez' socialist government because the geological risk in the country is virtually nil.

-By Dan Molinski, Dow Jones Newswires; (58) 414-120-5738; dan.molinski@dowjones.com

-Jeanne Liendo contributed to this article.