Caracterização faciológica de rochas carbonáticas e suas classes texturais em imagens de tomografia computadorizada associadas ao sistema permoporoso: uma abordagem aplicada às rochas do Pré-sal da Bacia de Santos

Abstract

The Santos Basin holds significant economic potential due to the extensive carbonate reservoirs of lacustrine origin in the Pre-salt. However, uncertainties persist regarding the lacustrine carbonate rocks of the Brazilian Pre-salt, due to the lack of analogous outcrops and the variability caused by diagenetic processes. Identifying the main lithological deposits, recognizing textural attributes in X-ray computed tomography (CT) images, and understanding the permoporous system of these rocks are geologically intriguing challenges. This research aims to define the main textures through CT images of lacustrine carbonate rock cores from the Barra Velha Formation in an oil field in the Santos Basin, and to understand the permoporosity behavior of each textural class to identify potential reservoirs. The methodology involved four stages: detailed geological characterization, permoporosity characterization, definition of the main textures in CT images, and analysis of the relationship between textures, lithofacies, and permo-porous systems. Six lithofacies and a textural classification with four classes were identified: laminated, bushy, nodular, and recrystallized, with a direct influence of advanced diagenetic processes on two textures and their permo-porous systems. This textural classification of lacustrine carbonate rocks from the Barra Velha Formation is effective in identifying features of interest for reservoirs and can be used by a specialist technician as a basis for training machine learning algorithms.