Petrobras, Brazil's state-controlled oil company, announced this Thursday, November 8, that it has discovered a large oil and gas field containing light oil off he coast of Brazil. The company just concluded the analysis of formation tests conducted in the second well of the area baptized as Tupi.
The findings are in the bloc BM-S-11, located in the Santos Basin, in the pre-salt layer. According to the Agência Petrobras de Notícias, the company's news agency, the volume of light oil (28º API) is estimated between 5 billion and 8 billion barrels of oil and natural gas.
Currently, the country has proven reserves – which have been confirmed and may be extracted – of oil and gas of 12.5 to 13 billion barrels. This means that the volume of oil and gas announced today by Petrobras is the equivalent of nearly half the total volume of Brazilian reserves.
According to the release, the company also made a local assessment of the petroleum potential of the pre-salt layer in the basins located in the Brazilian south and southeast.
"Should the estimated recoverable volumes of oil and gas in the pre-salt reservoirs be confirmed, then they will significantly increase the amount of oil in Brazilian basins, placing Brazil among the countries that have large oil and gas reserves," the agency informed.
Petrobras also announced that so far, the wells that reached the pre-salt layer and have been tested show, up to now, "high productivity of light oil and natural gas."
These wells are located in the basins of Espírito Santo, Campos, and Santos. The Santos Basin ranges from the municipality of Cabo Frio, in the southeastern Brazilian state of Rio de Janeiro, to the upper portion of Florianópolis, capital of the southern state of Santa Catarina.
The pre-salt layer is comprised of reservoir-rocks located underneath a large layer of salt that ranges from the coast of the state of Espírito Santo (in the Southeast) to Santa Catarina, with over 800 kilometers of length and up to 200 kilometers of width, in depths ranging from 1,500 to 3,000 meters under water, and 3,000 to 4,000 meters underground.
Light oil is the best quality oil; the higher the API degree, the finer the oil it produces. The Campos basin contains mostly heavy oil, which needs to be mixed with the light variety during the refinement process.
Petrobras is the operator in charge of the area in which the reserve is located, and owns a 65% share; British company BG owns 25%, and the Portuguese Petrogal – Galp Energia, 10%.