A trio of major presalt oil accumulations in the deepwater Santos Basin offshore Brazil have been declared commercial by operator Petrobras, as expected.

The Guara South, Tupi North-east and Florim fields add a combined 1.214 Bboe to the operator’s recoverable reserves, says the company, which submitted the declaration to Brazil’s National Petroleum, Natural Gas and Biofuels Agency (ANP). These areas fall, of course, under the Transfer of Rights Agreement.

The suggested names for the ‘new’ fields are Sul de Sapinhoá (South of Guará), Sépia (Tupi North-east) and Itapu (Florim). The presalt reservoirs contain good quality 26º-29º degrees API oil.

During the Mandatory Exploratory Plan, Petrobras collected 3-D seismic data for all the areas and drilled three mandatory and two additional wells to delimit and characterize the reservoirs. Three formation tests and one extended well test were also carried out to assess reservoir productivity.

Sépia and Itapu are located between 185-260 km offshore Rio de Janeiro State in water depths ranging from 1,850-2,250 m (6,070-7,382 ft). Sul de Sapinhoá is around 320 km off the coast of São Paulo State in water depths ranging from 2,200-2,250 m (7,218-7,382 ft).

Petrobras added that, in line with its 2014-2018 Business and Management Plan, commercial production from Sépia and Itapu is planned to flow in 2018 and 2020 respectively. The company is currently studying alternatives for the development of the Sul de Sapinhoá field and will announce the planned production startup date when its 2015-2019 Business and Management Plan is released.

With the declaration of commerciality for these three fields, the formal process of reviewing the Transfer of Rights agreement will get underway on a block-by-block basis, based on the technical and economic assumptions for each area. The review is expected to be completed next year.

This review process is already under way for the Franco and Sul de Tupi areas, declarations of commerciality for which were submitted in December last year. The only area under the Transfer or Rights agreement not yet declared commercially viable is Entorno de Iara, although Petrobras says that declaration is expected by December this year.