Estratigrafia de fraturas aplicada a rochas carbonáticas com base em dados de GPR e testemunhos de sondagem

Abstract

Fracture stratigraphy is essential to understand the structural segmentation of carbonate reservoirs and its implications for fluid circulation. This study analyzed fracture stratigraphy using Ground Penetrating Radar (GPR) data and drill cores in an outcrop of the Jandaíra Formation. This formation is composed of intensely fractured and karstified carbonate rocks, which allows a detailed analysis of the structural connectivity and segmentation of the layers. Four inlines of a GPR cube were interpreted, and one of them was correlated with a drill core to corroborate the interpretation. From the GPR images, it was possible to interpret the fractures and fracture units, in addition to estimating the geometric parameters of the fractures, such as frequency (P10), coefficient of variation (CV) and fracture spacing ratio and index (FSR/FSI). The analysis of the geometric parameters and the correlation with the well data demonstrated that the stylolites played a fundamental role in the compartmentalization of the fracture units identified in the GPR images. These stylolites fragmented the fracture units previously interpreted in the GPR images into subunits, acting as mechanical barriers and preventing the propagation of the fractures through them. The results obtained highlight the potential of the GPR method in the identification of the fracture units. However, the incorporation of complementary data, such as the drill core, was essential to highlight the presence of the stylolites, which are directly related to the spatial distribution of the fractures.