There is no evidence that the NSA is giving information from Petrobas to US oil companies to give them a competitive advantage.
What you posted is just the advocacy center's stated purpose--to help facilitate bids by US companies for foreign contracts.
I know the US government gets directly involved when dealing with companies like Lockheed Martin exporting military equipment. And I'm sure the NSA would share military secrets with defense contractors, but that is directly in their scope of mission to protect national security.
Stealing trade secrets to pad the bottom line of US companies is not part of their mission, and so far you've posted nothing to prove they are violating their mission in this way.