Análisis Sedimentológico y Petrográfico de las Formaciones Rayoso y Diamante en el Norte de la Cuenca Neuquina, sur de Mendoza

LOTHARI, LUCAS; GÓMEZ, RICARDO; TUNIK,MAISA; TOFFANI, MAURICIO

Mendoza

Congreso; 10 Congreso de Exploración y Desarrollo de Hidrocarburos; 2018

The Neuquén basin is one of the main basins generating hydrocarbons in Argentina. This, along with a large sedimentary record, has made it the subject of numerous geological studies. Most of these studies focus on the center of the basin, with very little background in the area of the high Mendoza mountain range, where this paper is developed. The rocks studied belong to the Bajada del Agrio Group, composed of the Huitrín and Rayoso Formations, and the Diamante Formation, equivalent to the Neuquén Group. These units correspond to the transition between the postrift and foreland stages (Early Cretaceous-Late Cretaceous).The objectives of this work are to determine the sedimentary paleoenvironment, in order to generate a depositional model that allows prediction of the distribution of facies and analysis of the petrography of red bed, emphasizing the characterization of porosity and diagenesis. The latter is very important for the exploration and exploitation of hydrocarbons.With these objectives, a Selley-type sedimentological profile was built in the Vega de Los Patos locations, approximately 70 km N of Malargüe, in which 16 facies, five facies associations and two depositional sequences were determined. The paleoenvironmental interpretations of the facies associations allow us to infer that the analyzed section fits the depositary model of mega fluvial fans or mega abanicos fluviales. This model allows relating the vertical variations of the facies with the progressive migration of the system, which could be related to pulses of tectonic uplift. For the petrographic analysis, eight samples of average sandstones were taken. These were classified as feldspathic lithoarenites and lithoarenites, which showed visual porosity values of 6% on average. They are affected mainly by the precipitation of carbonate, zeolithic cements and to a lesser extent by ferruginous cements.Recent studies on fluvial fans highlight the importance of this type of deposits both in the sedimentary record and in current basins, being of particular interest for their characteristics as potential hydrocarbon reservoirs.