BP is selling its substantial stake in one of 14 oil interests in Brazil as part of a global portfolio optimization program, the company said.

BP said it agreed to sell its 60 percent interest in the Polvo oil field in shallow waters offshore from Rio de Janeiro to Brazilian HRT Oil & Gas Ltda, a subsidiary of HRT Participacoes em Petroleo S.A., for $135 million cash.

HRT will be making the purchase from BP Energy do Brasil, BP said. The other 40 percent stake in the field is owned by Danish energy major Maersk.

Commercial production at the field began in 2007 and is run by BP since it bought the field from Devon Energy.

The field produces about 13,000 barrels of oil daily with BP taking a 60 percent share.

BP said the deal was part of its global optimization program and expects to close it in the second half of 2013, subject to Brazilian regulatory approval.

"Over the past two years BP has built a significant portfolio of upstream interests in Brazil which offer long-term growth potential," BP Brazil President Guillermo Quintero said.

"We are now actively engaged in exploring this new acreage."

Quintero said the sale "is part of our ongoing global portfolio optimization as we reposition the company for long-term growth."

The energy giant has interests in 14 exploration and production blocks in Brazil. It purchased interests in 10 exploration and production blocks, including the shallow-water Polvo field, from Devon Energy in 2011 and farmed into four deep-water blocks operated by Brazilian energy multinational Petrobras a year later.

Earlier in 2013 BP announced a successful flow test at its operated Itaipu discovery in the Campos basin, one of the blocks it acquired earlier from Devon.

The Polvo field lies in the southern part of the Campos basin, about 60 miles off the coast of Rio de Janeiro, in water depths of around 330 feet.

Despite the sale BP retains significant interests in Brazilian energy sector, where began operations in 1957. BP Energy do Brasil is one of four BP businesses in the country, Biocombustive is dealing in biofuels, Air BP trades in aviation fuel and Castrol handles lubricants.

BP says it has plans to enter Brazil's marine fuels business. Earlier this year BP and Brazilian group EBX signed an agreement to form a joint venture for the distribution of marine fuels in the country.