Chevron and YPF on Friday signed a new exploration deal that will include resources in the Vaca Muerta shale play, the companies said.

YPF chief executive Miguel Galuccio and Chevron executive Ali Moshiri met at the company’s headquarters in Buenos Aires Friday and signed the deal.

The accord with the US supermajor intends to apprise an area in Vaca Muerta, Neuquen as well as mature fields, the recently renationalised Argentine firm said in a statement.

The memorandum of understanding will “explore and evaluate certain areas of mutual interest on conventional and non-conventional opportunities,” Chevron said in a statement.

Chevron added that it had been working with the company consistently since the early 1990s. It did not elaborate on the details of the agreement.

Spanish giant Repsol, still seething following the expropriation of the bulk of its stake in the company earlier this year, immediately said it planned to take legal action.

“We do not plan to let third parties benefit from illegally confiscated assets,” a spokeman said.