FACTBOX-Major oil companies working in Ecuador

Oct 5 (Reuters) - President Rafael Correa of Ecuador has issued a surprise decree ordering foreign oil companies to hand over 99 percent of the extra crude revenues they earn over a benchmark price set in their contracts.

The law previously obliged them to hand over half of the extra windfall revenue, and the companies could lose a total of $830 million a year from the change.

The average benchmark price in the contracts is about $23 a barrel, while Ecuador's Napo and Oriente crudes traded at an average of around $60 a barrel in August.

Left-winger Correa wants to renegotiate foreign oil contracts to bolster the state's share in production and take advantage of soaring world crude prices -- as his ally, President Hugo Chavez of Venezuela, has done in his OPEC nation.

Here is a list of the major companies affected by the measure and some reactions:

* Spain's Repsol YPF (REP.MC) produces around 65,000 barrels per day. Repsol's three contracts in Ecuador are scheduled to expire in 2012. The company said the impact would be minor because Ecuador is a small part of its output.

* Private French company Perenco produces about 30,000 bpd. Perenco's two contracts are due to expire in 2010 and it has another contract that ends in 2021. The company has not commented on the decree.

* Petrobras PETR4.SA produces 35,000 bpd. Its main contract for the Palo Azul oil field, which produces most of its output, expires in 2022. Foreign Minister Celso Amorim, visiting Quito, said the company wanted to stay in Ecuador and saw flexibility in the government's negotiating position.

* Andes Petroleum, a consortium led by PetroChina (0857.HK), produces around 60,000 bpd. The company has not commented.

* CitiOriente, a small U.S. private operator, produces around 3,000 bpd and its contract is up in 2021.

* Local hydrocarbons association chief Rene Ortiz, who represents private oil companies working in Ecuador, said the move by the government was equivalent to "nationalization."

(Sources: Reuters, company Web pages, hydrocarbon association data and government figures.)