* Exchange-rate losses wipe out operational gains
* Currency helps total debt rise 44 percent (Adds company comment, financial information)
By Jeb Blount and Rodrigo Viga Gaier
RIO DE JANEIRO, Nov 12 (Reuters) - Brazilian state-led oil company Petrobras posted a loss of 3.76 billion reais ($1.01 billion) in the third quarter as lower oil prices, a weaker Brazilian currency against the dollar and the country's worst recession in decades crimped revenue.
It was the third loss in five quarters at Petroleo Brasileiro SA, as Petrobras is formally known, and widely missed market expectations for a loss of about 800 million reais. A year earlier, Petrobras recorded a 5.34-billion-real loss.
"Our strong operational result was consumed by a decline in the exchange rate," Chief Financial Officer Ivan Monteiro told reporters in Rio de Janeiro.
He said Petrobras is "working every day to cut costs and improve our operations" and find ways to raise new cash and restructure its debt profile.
Monteiro and the company's chief executive, Aldemir Bendine, who joined earlier this year from Banco do Brasil SA, are struggling to cut costs and sell assets as they seek to maintain key investments in giant offshore oilfields and cut the company's debt, the largest in the oil industry.
Petrobras' total debt expanded 44 percent to 506.6 billion reais since the end of 2014, largely as a weaker real drove up the local currency value of its mostly dollar debts. In dollars, its debt shrank 4 percent to $127.5 billion, still among the biggest of any industrial company on the planet.
The company hopes to end 2015 with $22 billion in cash and has about $25 billion of credit offers from lenders to try and cover its spending needs, Monteiro said.
Despite little progress on a plan to sell $15.1 billion of assets by the end of 2015, Monteiro said investor interest is strong and he's confident planned trips to Mexico, the United States, the United Kingdom, Canada and China will find buyers to help meet the target. Without asset sales, Bendine has said it will be hard to finance the company's debt.
Efforts to boost revenue and control debt have been complicated by falling oil prices, lower demand for fuel in a weak Brazilian economy and the fallout from Petrobras' central role in the largest corruption scandal in Brazil's history.
Net sales, or total sales minus sales taxes, fell 6.9 percent to 82.2 billion reais compared with 88.4 billion a year earlier. The price of Benchmark Brent crude was 50 percent lower in the third quarter than a year earlier.
Earnings before interest, taxes, depreciation and amortization, a key measure of cash generation known as EBITDA, rose 82 percent to 15.5 billion reais from 8.49 billion reais.
But output was flat. Production in the quarter rose 1.9 percent to 2.80 million barrels a day of oil and equivalent natural gas in Brazil and abroad from 2.77 million barrels a day a year earlier. Production was 1.2 percent higher than in the second quarter.
The operating profit rose to 5.81 billion reais, reversing a year-ago loss, when the company had one-time write-downs resulting from the corruption scandal.
The operating result was bolstered by lower sales costs. General and administrative expenses were marginally higher, exploration costs were slightly lower and tax costs were nearly six times higher than a year earlier.
Financial costs, though, wiped out operating gains.
The 36 percent year-on-year decline in the value of Brazil's real against the U.S. dollar resulted in 6.40 billion reais of non-cash exchange rate losses. The real was 13 percent weaker than in the second quarter.
$1 = 3.77 reais Reporting by Jeb Blount and Rodrigo Viga Gaier; Additional reporting by Caroline Stauffer in Sao Paulo; Editing by Chizu Nomiyama and Leslie Adler