LOL will never happen only dreams, Petrobras will take it to the Brazilian courts and that will be the end of the dream.
Anyone can agree to arbitrate a disagreement or legal issue, but the key word is "agree". Simply because one of the parties in a dispute desires to enter into arbitration does not take away another party's right to go to court.
So the pdf you posted said Vantage was seeking to arbitrate, does it say anything about Petrobras agreeing to arbitrate in Texas? LOL sure. What happened to references