A judge barred 17 Chevron executives from around the world from leaving Brazil in an oil spill investigation as prosecutors readied new charges over a second spill involving the US energy giant, local media reported Saturday. The Chevron brass -- five US nationals, five Brazilians, three Australians, two French nationals, a Canadian and a Briton -- can only leave Brazil with court approval, Judge Vlamir Costa of Rio de Janeiro state ruled. In November, Chevron was blamed for a major spill in the Frade Field area off Rio de Janeiro state, with Brazil's National Petroleum Agency (ANP) calculating that some 3,000 barrels of crude were spilled. Brazilian authorities as a result suspended all of Chevron's drilling operations and denied it access to huge new offshore fields, which ANP says have reserves that could surpass 100 billion barrels of high-quality recoverable oil. Thursday, Chevron reported a minor spill in the same area that caused it to stop production in Brazil. The company has not said if the two spills are related but authorities suspect the second was caused by the first. Chevron said it would conduct a comprehensive technical study and prepare a complementary study to better understand the geological features of the area, working with its partners and seeking necessary approvals from ANP. So far the US firm has been fined 30 million dollars and kept from new exploration operations. Prosecutors also have announced legal action against Chevron, its Brazilian unit and oil drilling contractor Transocean, seeking $11 billion over the November spill.