RIO DE JANEIRO, Oct 7 (Reuters) - Brazil's government

has set a minimum total payment of 10.2 billion reais ($1.91

billion) for an upcoming auction offering stakes in three

pre-salt oil fields already in production but not yet

contracted, state-run firm Pre-Sal Petroleo (PPSA) said.

The auction, scheduled for December 4 at the Sao Paulo-based

B3 stock exchange, will offer stakes of 3.5% in the Mero shared

reservoir, 0.551% in Tupi, and 0.950% in Atapu. All are

currently owned by the federal government.

The highest minimum bid was set for Mero at 7.65 billion

reais, followed by Tupi at 1.69 billion reais and Atapu at

863.32 million reais, PPSA said in a statement on Tuesday.

Petrobras, which operates the fields, is seen as

a likely participant. Its chief executive Magda Chambriard has

previously said the company evaluates all oil and gas area

auctions.

($1 = 5.3285 reais)