Abstract: The Cretaceous Petroleum System in the Northwest of Argentina

Carlos Mombru, Ricardo Gomez Omil, Marshall Patricio

The Cretaceous Petroleum System is characterized by: Lacustrine - Marine source-rocks (Kerogen type II-III) concentrated in the Upper Cretaceous (Yacoraite Formation, post-rift or sag stage) and distributed in 3 different depocenters.The main fluid found is oil, and not gas because of the low degree of maturity. Short and long migrations could be expected because of the existence of good carrier sandstones. The reservoirs may be sandstones, oolitic limestones and also volcanics. Very good seals can be found in the Yacoraite shales and limestones. The traps can be found in different tectonic environments: inner folded thrust belt, outer folded thrust belt (involving tectonic inversion), and foreland (mainly tensional faulting related with rifting and afterwards inverted movement). All the dicovered traps are in anticlines and in many cases have a stratigraphic component. Some traps have been conformed during the Andean Orogeny, and in other cases during the Lower Tertiary.

AAPG Search and Discovery Article #90951©1996 AAPG International Conference and Exhibition, Caracas, Venezuela