View of Anelo, the nearest town to the drilling wells of Vaca Muerta Shale oil reservoir, in the Patagonian province of Neuquen some 1180 Km south-west of Buenos Aires, Argentina on December 4, 2014. YPF has an agreement with US Chevron to exploit Vaca Muerta, the world's second largest reserve of shale gas and fourth largest reserve of oil, estimated to contain the equivalent of 27 billion barrels. AFP PHOTO / JUAN MABROMATA (Photo credit should read JUAN MABROMATA/AFP/Getty Images)
