QUITO: Ecuador has signed contracts for oil production in three Amazon fields with consortia including US and Colombian companies, officials said.

The 20-year contracts signed Monday will provide for $130 million in new investment and $496 million in new revenues for the country, according to Non-Renewable Resources Minister Wilson Pastor.

The three relatively small fields have probable reserves of 18 million barrels of crude, with total production of 15,000 barrels a day.

Ecuador, the smallest producer in the Organization of the Petroleum Exporting Countries (OPEC), currently produces 504,000 barrels per day, of which 285,000 is exported.

President Rafael Correa's leftist government in 2010 began renegotiating 33 foreign oil contracts following a law reforming the sector to give Ecuador 100-percent ownership of its crude oil production.

Under previous contracts oil companies kept 18 percent of production regardless of the cost of petroleum, which Correa said was unfair.

In November 2010 Ecuador canceled five existing foreign oil contracts, including with US, South Korean and Chinese firms.

But other big firms successfully renegotiated their contracts, including Repsol-YPF, Chile's ENAP, China's Andes Petroleum and PetroOriental, and Italy's ENI.