Controles estructurales y magmáticos en reservorios de la Formación Mulichinco en el yacimiento Volcán Auca Mahuida, Provincia de Neuquén, Argentina

Abstract

The Auca Mahuida volcano, 37º45'S and 68º56'W, is developed northeast of the Neuquén basin, in the Neuquén Embayment. The sedimentary filling of the basin in this area comprises a petroleum system which was affected for this Pliocene – Pleistocene magmatism. The analysis of well data, satellite images and geological background information has allowed interpretation of structures in an area located northeast of the main crater, and establishes the control they exert together with the magmatism in the reservoir conditions of the Mulichinco Formation. This work shows that borehole imaging and satellite images constitutes an essential tool in areas where seismic acquisition is not applicable due to the topography and the high acoustic impedance of the upper basaltic cover. The identified intrusive bodies have the same strike and dip that the previous structures which indicates that the magmas used these ways to intrude. Because of the structural study focused on the Mulichinco Formation, four blocks that disconnect the fluid in the reservoirs were defined. The petrophysical conditions were not altered by metamorphism but the presence of hydrothermal activity produced a hydrocarbon remigration. Large amounts of gas indicate that the increased heat generated by the intrusion, increased the maturation in source rocks, going to from the oil window to the gas window. The study of the fluids and their interaction with the subsurface structure allows expanding the knowledge of the structural model and to give a greater precision in the development of the oilfield.