Petrobras March output falls on repairs, shutdown

* Company began maintenance at main offshore oil fields

* Petrobras lost output when Chevron shut Frade field

RIO DE JANEIRO May 4 (Reuters) - Brazil's state-led oil company Petrobras said on Friday that output fell in March, the result of maintenance on key offshore platforms and the suspension of production at a field it owns with Chevron .

In March Petrobras produced an average of 2.60 million barrels of oil and natural gas equivalent per day (boepd) from fields in Brazil and abroad. The figure was 0.7 percent less than a year earlier and 3.7 percent lower than in February, according to a Petrobras statement and data on the company's Web site.

Petrobras said it lost an average of 105,000 boepd of output from shutdowns at Frade, the field it owns in conjunction with Chevron, the majority partner, and Japanese investors. The field was the site of a November spill and a small leak earlier this year that led to its suspension by regulators.

The amount is equivalent to 4 percent of Brazilian output and about 5 percent of Petrobras output in Brazil, according to Brazil's oil regulator, the ANP, and Petrobras.

Rio de Janeiro-based Petrobras stopped output from the P-51 floating production, storage and offloading (FPSO) ship in the Marlim sul field, and the P-57 FPSO in Jubarte field and the FPSO Brasil in the Roncador field for maintenance, the statement said.

Marlim Sul, Roncador and Jubarte were the No. 1, No. 2 and No. 4 producing fields in Brazil in February according the ANP.

The three fields produced 29 percent of Brazil's 2.63 million boepd in February, the ANP said.

Petrobras also lost output when Chevron decided to temporarily shut the Frade offshore field adjacent to Roncador to explore the causes of oil spills and leaks in the area that began in November.