A geoquímica orgânica aplicada à Formação Irati-Bacia do Paraná, poço SC-20-RS, área de Pinheiro Machado RS

Abstract

This study deals with the chemostratigraphic characterization of the Irati Fm. (Permian Paraná Basin), as well as with the assessment of its oil generating potential. A systematic acquisition of core samples was done from well SC-20-RS, on which analyses were performed for TOC, S, RI, Rock Eval Pyrolysis and Biomarkers. Based on this information, nine chemostratigraphic intervals (designated A - I from the base) were defined in the 57.7 meter thickness. With the biomarker based data obtained by liquid and gas chromatography it was possible to make a more detailed study of environmental variations and organic matter input, and to identify the depositional environment of the interval with the greatest oil generating potential in the well studied. The Member Assistance, characterized as having been deposited in a restricted environment, has the most promising interval (Interval E), which includes a section about 5 meters thick. It was observed that there is a greater preservation of hydrogen-rich organic matter(Type II) and increased TOC% when the environment becomes less restricted, and the salinity of the environment decreases, conditions which were also identified through biomarkers. The Irati Fm. is the source of bituminous shales used by Petrobras to obtain industrial oil, gas, and sulfur byproducts derived from the process of industrialization of these rocks. It is also a major generator of signs of oil found in the Paraná Basin, thus it is always of utmost importance to obtain data that may add to the knowledge about this formation