Integração de métodos petrofísicos para caracterização multiescala de sistemas porosos em rochas carbonáticas da Bacia Potiguar

Abstract

This dissertation presents a comparative analysis of petrophysical techniques applied to the characterization of porous systems in carbonate rocks, focusing on a set of 101 samples from the Potiguar Basin, of which 9 were exclusively allocated for digital analyses. The study integrated traditional methodologies, such as gas porosimetry and water saturation porosity, with advanced digital imaging techniques, including X-ray microtomography (Micro-CT), synchrotron radiation tomography (SR-CT), and Nuclear Magnetic Resonance (NMR) measurements. The research highlighted the complementary nature of these methods, demonstrating how each technique accesses specific fractions of the porous system: gas porosimetry proved highly efficient in determining interconnected volumes; water saturation revealed the fraction effectively occupied by mobile fluids; NMR stood out for its sensitivity to micropores; while microtomography enabled detailed characterization of structural connectivity and three-dimensional morphometry of the porous medium. The results indicate that variations between techniques are explained by factors such as the presence of unsaturated pores, trapped air, wettability limitations, and differences in image resolution. From a statistical standpoint, the integration of scatter plot analyses with ANOVA and Tukey HSD tests confirmed significant differences between lithofacies and among the applied methods, reinforcing the importance of multitechnique approaches in the petrophysical characterization of carbonate reservoirs.