It’s a big win for Chevron. Buying Hess without the Guyana project would have wiped out the biggest upside from the deal.

Chevron closed its $55 billion acquisition of Hess on Friday after winning a landmark legal battle against larger rival Exxon Mobil to gain access to the largest oil discovery in decades.

Chevron Corp. won its arbitration battle with Exxon Mobil Corp. and has closed its $53 billion deal to buy Hess Corp. more than 20 months after the takeover was announced.