Exxon Mobil plans to invest $200 million to boost natural gas output in Argentina’s Vaca Muerta Shale, a spokeswoman reported recently. The company has asked the government of Neuquén province for a 35-year unconventional production concession in the Los Toldos I Sur Block, which the company operates. The Vaca Muerta is one of the world’s largest sources of unconventional gas reserves, and attracting investment in the growing play there is a key priority for the Argentine government. ExxonMobil last year said it could invest more than $10 billion in shale projects over the region in the next 20 to 30 years. The company holds an 80% interest in the Los Toldos I Sur block, with Tecpetrol and Gas y Petróleo de Neuquén each holding 10% interests.