UPDATE 1-Petrobras secures $1.8 bln Bradesco loan for refinery -source

SAO PAULO, April 8 (Reuters) - Petroleo Brasileiro SA borrowed 4 billion reais ($1.8 billion) in a 17-year loan from Banco Bradesco SA to help pay for work on the Abreu e Lima refinery in northeastern Brazil, a source with direct knowledge of the deal said on Tuesday.