Nuevos aportes al conocimiento del Ciclo Precuyano en el subsuelo del sur de Mendoza: Yacimiento Cajón de los Caballos, Cuenca Neuquina, Argentina

DE LA CAL, H.; LAJOINE, F.; PAEZ, G.N.; FEINSTEIN, E.

Mendoza

Congreso; IX Congreso de Exploración y Desarrollo de Hidrocarburos; 2014

Instituto Argentino del Petróleo y del Gas

New contributinos to the knowledge of the Precuyano Cycle in the South of Mendoza subsurface:Cajón de los Caballos oil field, Neuquina Basin, Argentina The Cajón de los Caballos oil field is located in the Northern Neuquén Basin, in the Mendoza Province (Argentina). Wells drilled on this field show a thick sequence of volcanic and volcaniclastic rocks with interbedded sandstones, conglomerates and limestones, which can be correlated to the Precuyano Cycle, and that represents part of the syn-rift sequence of the Neuquina Basin. Based on electricallogs and cutting samples, the Precuyano Cycle was divided into four electrical facies, named "Lower Sequence", "Upper Sequence", "Andesite" and "Tordillo". Petrographic studies performed over a drill-core from the CC.a-5 well, show that the "Andesite" electrofacies is composed of two, highly altered lava flows with a high concentration of calcite veinlets with hydrocarbon impregnations. These two lava flows are separated by a thin layer of fluvio-lacustrine sandstones made of reworked pyroclastic material, evidencing the episodic nature of the volcanism. Major and trace elements geochemistry allowed the classification of these rocks as basaltic andesites to andesites, of calcalkaline signature. Finally, REE spidergrams, showed a clear correlation between these rocks and other Precuyano Cycle volcanic rocks, and allowing further discrimination from other andesitic units of the basin.