(Adds quote from Schlumberger executive)
BUENOS AIRES, April 12 (Reuters) - Argentina's state-run oil company YPF SA and Schlumberger AG, the world's top oil services provider, have reached a deal to invest $390 million in the Vaca Muerta shale formation, the companies said on Wednesday.
In a letter to the Buenos Aires stock exchange, YPF said a division of Schlumberger would invest the full amount and obtain a 49 percent stake in the 228.5 square kilometer (88.22 square miles) Bandurria Sur concession, where the two companies would develop a two-phase shale oil pilot project.
President Mauricio Macri was elected in late 2015 promising to drop the trade and currency controls that had scared off foreign investment during the previous administration.
Over the past 16 months he has moved to improve the business environment in part by cutting labor costs in the vast but barely tapped Vaca Muerta shale formation in Patagonia.
"We are very pleased with what the administration is doing and clearly we have confidence that Argentina as a country has a very rich resource base," Schlumberger's president of operations, Patrick Schorn, told Reuters in a telephone interview.
"Today, with the combination of a progressive-thinking administration that allows an environment that makes it very conducive for foreign investment, we have benefited from that together with our partners at YPF," he said. "So yes, we are very pleased about where Argentina is heading." (Reporting by Luc Cohen and Hugh Bronstein; Editing by Bill Trott)