(New throughout, adds details from Espírito Santo basin)
RIO DE JANEIRO, Sept 27 (Reuters) - Exxon Mobil Corp vastly expanded its presence in Brazil on Wednesday, winning a total of eight offshore blocks in the country's 14th oil bidding round, helping the cash-strapped nation to fetch a record 3.8 billion reais ($1.19 billion).
Exxon Mobil took six blocks in consortia with state-controlled oil giant Petroleo Brasileiro in the promising offshore Campos basin, after bidding 2.24 billion reais for one area alone. That was Brazil's highest-ever such bid.
The positive results came as a surprise, after Brazil's oil regulator ANP managed to sell just 1 out of 76 blocks on offer in the highly productive Santos basin by late morning.
Analysts had said lackluster oil price performance and dwindling cash for investments might have dented appetite.
But Exxon Mobil, which also made a record bid of 1.2 billion reais with Petrobras for a Campos block on Wednesday, helped Brazil achieve the record bonus take.
"We are anxious to work with the Brazilian government and our partners to develop the exploration of our winning blocks," Exxon Mobil said in a statement.
The U.S. oil major won two other blocks by itself in the same basin. The area abuts Brazil's pre-salt area, where hydrocarbons are trapped under a layer of salt below the ocean floor.
Asked after the auction why he spent so much on the bids, Petrobras CEO Pedro Parente said he had information suggesting the blocks were part of the pre-salt area, one of the world's largest oil discoveries in recent decades.
The auction was seen as a test of whether market-friendly reforms under President Michel Temer could tempt investors back to a sector struggling after years of state meddling and tarnished by a corruption scandal at Petrobras.
In the last round, in December 2015, ANP raised just 121 million reais, as tough local content rules under Temer's predecessor Dilma Rousseff discouraged major foreign companies from investing.
Brazil sold just 37 of the areas on offer. Still, the country raised well over the 1.69 billion reais ($529.85 million) it expected had it placed all 287 onshore and offshore exploration blocks.
Officials had said they expected to sell up to 40 percent of the blocks.
Environmental activists protested the auction and threatened to invade the Rio de Janeiro hotel where the round was taking place. They were removed after scuffling with hotel security staff.
Other winners included China's CNOOC and Spain's Repsol which took offshore blocks in the Espírito Santo basin with signing bonuses for 23.55 million reais ($7.38 million) and 23 million reais respectively.
The auction was Brazil's 14th round for blocks outside of the coveted pre-salt area and should gauge appetite for the country's second and third pre-salt rounds next month.
($1 = 3.1896 reais) (Additional reporting by Pedro Fonseca in Rio, Marcelo Texiera in Sao Paulo and Ernest Scheyder in Houston, Writing by Alexandra Alper and Guillermo Parra-Bernal; Editing by Jeffrey Benkoe, Susan Thomas and David Gregorio)