The Vaca Muerta Formation, commonly known as Vaca Muerta (Spanish for dead cow), is a geologic formation of Late Jurassic to Early Cretaceous age, located in the Neuquén Basin in northern Patagonia, Argentina. It is well known as the host rock for major deposits of shale oil and shale gas.
The large oil discovery in the Vaca Muerta Formation was made in 2010 by the former Repsol-YPF. The total proven reserves are around 927 million barrels (147.4×10 m), and as of 2014 YPF's production alone was nearly 45,000 barrels per day (7,200 m/d). In February 2012, Repsol YPF SA raised its estimate of oil reserves to 22.5 billion barrels (3.58×10 m). The US EIA estimates total recoverable hydrocarbons from this Vaca Muerta Formation to be 16.2 billion barrels (2.58×10 m) of oil and 308 trillion cubic feet (8.7×10 m) of natural gas, more than even the Neuquén Basin's hydrocarbon-rich Middle Jurassic Los Molles Formation holds.As of 2017, there were almost 500 fracking wells, one of the most fracked sites outside North America, and as of October 2024, there were over 1500 fracking wells.
