Venezuela's PDVSA said on Monday that it will pay Exxon Mobil Corp. $255-million (U.S.) in compensation for nationalized assets - less than a third of what the U.S. oil giant said it was awarded by an arbitration panel.
The South American OPEC member's state oil company issued a defiant statement saying it was deducting debts owed by Exxon, including PDVSA's repurchase of bonds linked to the nationalized project.

Maybe I am mistaken, but I think you are jumping the gun. Exxon did not agree to accept 255 million. The article only states that Vz would pay that amount. This is the same as if you were awarded $100,000 in court for breach of contract or persoanl injury and the defendant issued a News Release stating it would pay only $25,000. I am assuming that Exxon may very well have enforcement privileges in awards made by the Int'l Chamber of Commerce's Int'l Court of Arbitration similar to those it has in a case before the ICSID or it would not have wasted its time filing an action there. But whether it does or does not, the article only says that 255 mil is the amount that Vz said it would pay. In a case before the ICSID, as may also be the case before the ICA, it matters not what the defendant says it will pay because the party awarded the damages has enforcement rights in any of the 157 member nations where the losing party has assets. Thus, Vz could say it will pay only 100 million of a 4 billion award made by the ICSID tribunal but so what. When their assets are levied upon, they will be singing a different tune.