ExclusivePetrobras launches huge tender for up to eight deep-water rigs in BrazilState-controlled company's fleet set to grow again as it starts hunt for more high-spec rigBig tender: the Constellation Oil Services drillship Brava Star is one of many rigs operating for Petrobras offshore BrazilPhoto: ALEXANDRE GENTIL/PETROBRASFabio PalmigianiRio de Janeiro