Petrobras, the Brazilian oil giant, announced at the end of last week, the discovery of light oil in the Santos Basin. The company concluded on March 10 tests in the well 3-RJS-621, located in the part of the basin that belongs to the southeastern Brazilian state of Rio de Janeiro, 160 kilometers away from the coast, which revealed the presence of oil at 33 API degrees, measurement used by the American Petroleum Institute.
The API scale qualifies the density of the product. According to Petrobras, when the reading is above 28 degrees the oil is considered to be light and, the higher the graduation, the greater the possibility of “light” derivatives, such as gasoline, liquefied petroleum gas (GLP) and naphtha, a raw material for the petrochemical industry.
The commercial viability of the field is yet to be evaluated by the company, after sending an “evaluation plan” to the Brazilian National Petroleum Agency (ANP).
At the moment, according to a statement released by the company, the tests that have already been carried out “confirm the good quality of the oil and a high production potential.” The tests to verify the volume in the reserves should take a few months.
The well was perforated at a depth of 1,323 meters below the sea level and is part of the block BS-500. According to Petrobras, “about 40 meters of sandy reservoirs containing light oil” were found. In this case, the “sandy reservoirs” are porous rocks containing oil.
In the Santos Basin an enormous natural gas reserve had already been discovered, in 2003, evaluated in approximately 420 billion cubic meters, but that is not yet being exploited.
In the last two years, the government-owned company found light oil with commercial potential also in the Golfinho fields, in the state of Espírito Santo, in the Southeast of Brazil as well, and in Piranema, in Sergipe, state in the Northeast region of the country, which are due to start producing next year. Currently, about 70% of the Brazilian production is of heavy oil.