The Emerging Neuquén Vaca Muerta Shale Resource Plays: Highlights and Challenges

Fernando Sanchez-Ferrer
Principal Regional Geologist, Latin America, Shell International

The Vaca Muerta of the Neuquén Basin of Argentina has the potential to rejuvenate exploration activity in a region with a century of prior oil and gas production. The shale characteristics compare favorably with those from established North American resource plays, including the Barnett, Woodford, Utica, Duvernay and the Eagle Ford. Yet, in contrast to the cited examples, this unconventional opportunity is still in its infancy, with few longer term production tests available across the basin to calibrate the play.

The Vaca Muerta straddles the Jurassic-Cretaceous boundary in age and is preserved over much of the basins 139,000 square kilometers. The shale organic content is high, with a great majority of measurements attaining 4-6%. Its effective thickness (TOC>2%) outstrips even the best-endowed North American Unconventional opportunities. Similarly to the prolific Eagle Ford, which is generally accepted as a close analogue, Vaca Muerta exhibits a wide range of thermal maturities, associated with resource fluid transitions (dry gas, wet gas, light oil) that can be ascribed different values. Mineralogically, Vaca Muerta’s low clay percentages and high proportions of quartz and carbonates anticipate favorable fracability characteristics.

In this early phase of exploration, understanding of the Vaca Muerta opportunity requires sound application of geological first principles and appropriate use of play analogues. As new data becomes rapidly available, close work between the different disciplines is paramount. Technological integration, as well as understanding of local variability within an area of interest, will play a key role in the identification of the final sweet spots and the cost-efficient de-risking of the play.

AAPG Search and Discovery Article #90165©AAPG 2012 GEOSCIENCE TECHNOLOGY WORKSHOP, 2-4 December 2012, Buenos Aires, Argentina