Brazil judge nixes union lawsuit against Chevron Mon May 7, 2012 3:46pm EDT (Reuters) - A Brazilian judge threw out a civil lawsuit seeking to ban U.S. oil company Chevron (CVX.N) and oil drill-rig operator Transocean (RIGN.VX) (RIG.N) from operating in Brazil because of a November oil spill, court officials said on Monday. Mauro Souza Marques da Costa Braga of the Second Federal Regional Tribunal in Rio de Janeiro rejected the case, launched by FUP, Brazil's largest oil-workers' union federation, because its main aims are already part of an existing lawsuit. The judge said his rejection of the case has no bearing on its merit. Chevron and Transocean remain the subject of a 20 billion real ($10.5 billion) civil lawsuit over the November spill in the Frade field northeast of Rio de Janeiro operated by Chevron. Chevron and Transocean and 17 of their Brazilian and foreign employees are also the subject of a criminal case that carries penalties of up to 31 years in jail over the spill. Transocean, based in Switzerland, is the world's largest drill-ship operator. San Ramon, California-based Chevron is the No. 2 U.S. oil company. The 3,000-barrel spill was less than one-thousandth the size of the 2010 BP oil disaster in the Gulf of Mexico. Transocean, the drilling contractor in Frade, welcomed the judge's decision. "The judge has dismissed FUP's civil action in Rio de Janeiro," the company said in a statement. Since its filing, we questioned the legitimacy of the union's lawsuit, like the other two cases brought forward by prosecutor Eduardo Santos Oliveira. The cases are filled with errors about Transocean and its role. Chevron officials and FUP officials were not immediately available for comment. The Frade field is operated by Chevron, which owns 52 percent of the field. Petrobras, which owns 30 percent and a Japanese group, which own 18 percent, do not face legal action over the spill. Reporting by Jeb Blount; Editing by Phil Berlowitz