RIO DE JANEIRO (Reuters) - Drilling by U.S. oil major Chevron off Brazil's coast led to an oil spill near the company's Frade project, an official with Brazil's energy regulator ANP told Reuters on Monday.
Chevron says oil seeps have created a "sheen" with a volume of 400 to 650 barrels of oil in the vicinity of the project, which is located 370 kilometers (230 miles) northeast of Rio de Janeiro.
President Dilma Rousseff on Friday urged a thorough investigation of the incident, which may increase the scrutiny on safety in Brazil's offshore operations as it seeks to tap huge newly-found reserves and become a major oil exporter.
"What was detected is that with the drilling, there was an increase in pressure and there was a crack in the rock which caused the oil to leak to the surface," ANP Director Floriano Carvalho told Reuters.
A Chevron spokeswoman said in an e-mailed message that the causes of the incident are still being investigated.
Carvalho said that the leak is continuing and that the ANP had authorized Chevron to cap the well. Chevron had previously said it suspended drilling the well, but said that production was continuing. The company maintains that production activities are unrelated to the oil seeps. The spokeswoman did not immediately respond to request for comment on the closure of the well.
"Chevron Brazil is deploying experts from Chevron Corporation's global response team and continues to inform and work with government agencies and industry partners in response to the matter," the firm said in a statement on Sunday.
The Frade project is in the Campos Basin, which provides the vast majority of Brazil's oil production.
Chevron holds stakes in the Papa-Terra and Maromba projects in the Campos Basin. In the neighboring Santos Basin, Chevron holds a 20 percent stake in Block BS-4.
State oil company Petrobras expects output in Brazil to more than double to nearly 5 million barrels per day as its ramps up production from fields in the deep-water region known as the subsalt.
Petrobras has said that government-mandated platform shutdowns in Brazil have increased since the massive offshore BP spill in 2010 in the Gulf of Mexico.
(Reporting by Sabrina Lorenzi, writing by Brian Ellsworth;editing by Sofina Mirza-Reid)