At midnight Dec. 31, a deadline expired for all private companies with contracts to independently pump oil to agree to joint ventures that will give Venezuela's state oil company majority control.

The 32 operating agreements were signed between 1990 and 1997, when Venezuela's petroleum industry was open to private and foreign capital. The objective at the time - when the price of crude was below $10 US a barrel - was to increase production at low-priority oil fields that had been closed because of their location or lack of resources and which Petroleos de Venezuela S.A., or PDVSA, had no plans to reactivate.

As oil prices crept back up in recent years, President Hugo Chavez's government sought to boost its control and share of profits from the industry. In 2001, it passed a hydrocarbons law that made the operating agreements illegal by requiring oil production to be carried out by companies majority-owned by the government.

As of Sunday, Venezuela had successfully completed "the recovery" of the 32 fields, Venezuelan oil minister Rafael Ramirez said in a statement.

The government threatened to reclaim oil fields from companies that refused to sign the so-called transitional joint-venture agreements, which will later be converted into permanent agreements with PDVSA.

Chevron Corp., BP PLC, Royal Dutch Shell PLC and Brazil's state oil company Petrobras S.A. were among those that signed earlier.

Spanish-Argentine firm Repsol YPF was the last to sign earlier this week after buying out Exxon Mobil Corp.'s stake in the Quiamare-La Ceiba oil field. Irving, Texas-based Exxon Mobil had resisted the contract changes, which will significantly reduce the oil companies' share of profits and control over operations and could also undermine the value of their Venezuelan assets.

The state could take as much as a 90-per-cent stake in the new ventures. The amount the private companies have invested in the fields will determine the amount of control they have, Ramirez has said.

The 32 oil fields have been responsible for about 500,000 of Venezuela's officially declared production of 3.2 million barrels a day.

Venezuela is the world's fifth-largest oil exporter and has the largest proven reserves outside of the Mideast.