Exxon is exiting the Vaca Muerta to focus efforts elsewhere, including Guyana. : Exxon Mobil Corp. has agreed to sell most of its assets in Argentina’s Vaca Muerta shale patch to Pluspetrol SA, according to people familiar with the matter. The province of Neuquen, where the assets are located, has yet to sign off on the deal, said one of the people, who asked not to be identified because the discussions are private. Spokespeople for Exxon and Neuquen didn’t immediately respond to requests for comment. EconoJournal first reported Exxon’s agreement to sell to Pluspetrol.