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RIO DE JANEIRO, Nov 10 (Reuters) - Brazilian energy company OGX (OGXP3.SA: Quote, Profile, Research) on Tuesday said it boosted estimated hydrocarbon resources to 6.7 billion barrels from 4.8 billion barrels.

It said the volumes were certified by consulting company DeGolyer and MacNaughton, which reviewed seismic data from five blocks in the offshore Campos basin and in the Espirito Santo basin and recently acquired blocks of the Parnaiba basin.

"We're very, very proud of the result," said Paulo Mendonca, OGX exploration and production director in a conference call with analysts.

The DeGolyer and MacNaughton study concluded the company had resources of 6.7 billion barrels of oil equivalent and 212 million barrels of "net contingent resources," without elaborating on the terminology.

Oil resources estimates are based on less geological information than reserves, which publicly listed oil companies report so that investors know how much crude they have access to.

Reserves estimates generally require oil field drilling rather than simply using seismic data.

The company's shares were down 3.09 percent to 1,473 reais on the Sao Paulo stock exchange in late morning trade, compared with a 0.1 percent slump for the broader index.

"OGX is reviewing its business plan to reflect the scope of the additional activities to support the process of transforming resources into proven reserves," the company said in a statement.