BRASILIA, July 7 (Reuters) - Brazil's Senate may vote on Wednesday on a bill ending state-run oil company Petrobras' leadership and mandatory minimum stake in a giant offshore oil district known as the subsalt, a key leader in the Brazilian upper house of Congress said on Tuesday.
The Senate will likely put the bill up for a vote in the morning, said Delcídio Amaral, the leader of the government's ruling Workers' Party in the Senate.
A vote could be delayed or put off if the Senate fails to complete votes on two presidential provisional decrees, Amaral added. Under Brazilian congressional rules, provisional decrees must be approved or rejected before any ordinary bill can be put to a vote.
The bill aims to attract new investment to the subsalt, spark higher resource output and boost the flow of royalties to Brazil's Treasury. The subsalt is an offshore region near Rio de Janeiro and Sao Paulo where 50 billion to 100 billion barrels of oil and natural gas are trapped deep beneath the seabed by a layer of mineral salts. That is enough oil to supply all needs in the United States for seven to 14 years.
Petroleo Brasileiro SA, as Petrobras is formally known, has said its precarious finances and more than $120 billion of debt, the largest of any oil company, make it impossible for it meet a legal requirement that it finance at least 30 percent of any subsalt development.
The bill also ends a requirement that Petrobras serve as sole operator of any subsalt investment group.
As operators have final say over many contracting and timing decisions, few oil companies would want to pay the huge costs needed to develop the resources without a greater say over operations, bill supporters say.
Despite opposition to the bill from many in Rousseff's Workers' Party who see the Petrobras subsalt requirements as a patriotic defense of national oil sovereignty, the government has accepted that it will likely lose a battle to prevent the changes, Reuters reported last week.
If passed by the Senate, it will also require passage by the Chamber of Deputies, Brazil's lower house and the signature of Rousseff. (Reporting by Maria Carolina Marcello and Eduardo Simoes.; Additional reporting by Jeb Blount in Rio de Janeiro.; Writing by Jeb Blount; Editing by Bernard Orr)