RIO DE JANEIRO, Dec 13 (Reuters) - Brazilian state-run oil company Petroleo Brasileiro SA (PETR4.SA) expects to sign a deal to sell its TBG natural gas pipeline unit next year, Chief Strategy Officer Rafael Chaves said during a presentation to a Rio de Janeiro industry group on Monday. In August, Reuters reported U.S. private equity firm EIG Global Energy Partners made a binding offer worth several hundred million dollars for the asset. read more