Jorge A. Orrego-Ruiz

Finding a relationship between the composition and the emulsifying character of asphaltenes through FTICR-MS

espanolRESUMEN Los estudios mediante petrografia, catodoluminiscencia, SEM, inclusiones fluidas y geoquimicos de tierras raras (REE) en muestras de nucleo de la Formacion Rosablanca en el sector de la Mesa de Los Santos, determinaron dos tipos de material: la roca caja clasificada como Packstones y Grainstones, y venas que texturalmente exponen tres tipos de relleno (agregados granulares, agregados granulares de cristales elongados, agregados fibrosos). La diagenesis esta caracterizada por procesos de disolucion, cementacion, compactacion, fracturamiento y circulacion de fluidos por fracturas durante al menos tres episodios; estos procesos en el area de estudio fueron coetaneos con los regimenes tectonicos distensivos y compresivos dominantes regionalmente durante el Cretacico, el Paleogeno y el Neogeno. Los fluidos que generaron los distintos tipos de relleno en las venas fueron salmueras que pertenecieron al sistema H2O-NaCl-CaCl2 con salinidades comprendidas entre 0,03-12,96 % wt eq NaCl, derivadas de la Formacion Rosablanca que fue depositada bajo condiciones oxicas reteniendo su caracter marino e implicando una procedencia autoctona de los REE presentes en las venas. Las condiciones de atrapamiento de las inclusiones fluidas durante el primer evento fueron heterogeneas a partir de una mezcla inmiscible de salmueras e hidrocarburos, mientras que, en el segundo, fueron homogeneas con procesos post-atrape posteriores. EnglishABSTRACT Studies conducted by means of petrography, cathodoluminescence, SEM, fluid inclusion and REE geochemistry in core samples from the Rosablanca Formation in the Mesa de Los Santos sector, identified two types of material: the host rock classified as Packstones and Grainstones, and veins that texturally expose three types of filling (blocky texture, blocky elongate texture, fibrous texture). Diagenesis is characterized by dissolution, carbonate cement precipitation, compaction, fracturing and fluid circulation through fractures during at least three episodes; these diagenetic processes were contemporaneous with the distensive and compressive tectonic regimes regionally dominant during the Cretaceous, Paleogene and Neogene in the study area. The fluids that generated the different types of texture inside the veins were brines that belonged to the H2O - NaCl - CaCl2 system, with salinities between 0.03 - 12.96 % wt eq NaCl, derived from the Rosablanca Formation that was deposited under oxic conditions, retaining their marine character and implying an autochthonous origin for the REE present in the veins. The conditions of entrapment for fluid inclusions during the early event were heterogeneous, arising from an immiscible mixture of brines and hydrocarbons, while in the second, they were homogeneous with later post-entrapment processes.