BUENOS AIRES, July 24 (Reuters) - Argentina's giant Vaca Muerta shale oil and gas field has 661 billion barrels of oil and 1,181 trillion cubic feet of natural gas resources, according to estimates by state-run energy firm YPF YPFD.BA in a presentation seen by Reuters. YPF operates in 3 million net acres in the formation, an area with 316 billion barrels of shale oil and 353 trillion shale natural gas resources, according to the presentation. (Reporting by Karina Grazina; Editing by Gary Hill) ((caroline.stauffer@thomsonreuters.com)(+55 11 5644 7726)(Reuters Messaging: caroline.stauffer.thomsonreuters.com@reuters.net)) Keywords: ARGENTINA YPF/VACAMUERTA