Ecuador says to take at least 85 pct oil revenues

* Ecuador seeks to increase state revenue from oil sector

* New petroleum contract negotiations to start this month

By Santiago Silva

QUITO, Aug 17 (Reuters) - Ecuador's government will take at least 85 percent of revenue under a new round of oil contracts to be negotiated with private petroleum companies, Ecuador's minister for oil policy Wilson Pastor said on Tuesday.

The state currently receives an average 65 percent of the revenues generated by private firms operating in the Andean country.

"We are going to raise the participation (of the state) to at least 85 percent," Pastor, who holds the rotating presidency of OPEC this year, told reporters.

Profit margins for investment in new oil fields will be 18 percent to 22 percent under the new pacts while profitability will be 15 percent to 18 percent for investments in producing fields, Pastor said.

Last week, he turned over new model contracts to petroleum companies and said he plans to start negotiating the new pacts on Aug. 23.

Firms operating in Ecuador include Spain's Repsol , Brazil's Petrobras and Italy's Eni.

Ecuador has said it wanted to maintain oil production by private companies at around 200,000 barrels per day following the signing of the service contracts.

The government wants state oil production to reach 384,000 barrels per day (bpd) by 2013 from around 264,000 bpd currently.

Companies that do not sign the new deals will be paid for their assets in Ecuador and leave the country, President Rafael Correa has said.

His government has already taken over the local assets of U.S. oil company Occidental Petroleum and France's Perenco. Analysts say it has done so without paying a high political cost.

Correa's main regional allies, Venezuelan President Hugo Chavez and Bolivia's Evo Morales, also have introduced reforms and nationalized the assets of foreign investors in a bid to increase state revenue from energy and mining companies.