O uso de afloramentos digitais para modelagem de uma rede de fraturas discreta determinística: exemplo da Caverna Cristal (Cráton do São Francisco, NE - Brasil)

Abstract

MDAs demonstrate great potential for generating high-precision, georeferenced qualitative and quantitative data that can be incorporated into predictive models. This study investigated the fracturing process in an outcrop analogous to pre-salt reservoirs using its Digital Outcrop Model (DAM). The study area encompasses Access 1 of Caverna Cristal, located in Morro do Chapéu, Bahia, in the São Francisco Craton. Caverna Cristal developed in a 50-meter carbonate sequence in the Caboclo Formation. The main objective of this project was to evaluate the potential of MDAs in the structural and morphometric analysis of Caverna Cristal. The steps included subdivision of the cave's DAM, reprocessing of point clouds, structural interpretation, and morphometric analysis. The filters and algorithms applied to the mapping of fractures and fracture planes highlighted surface orientations, chromatic and morphological variations, and highlighted zones of hydrothermal alteration. Morphometric analysis yielded geometric and spatial data, including area, volume, maximum width, length, and height of the cave: 68.69 m2; 2,330.94 m; 46,66 m; 87.91 m; and 35.67 m. From the roof of the MDA, 64 fractures were mapped, with preferential directions of NE-SW, NW-SE, and NNE-SSW, and approximately vertical dip intensity, with decreasing lengths ranging from 44 m to 2 m, respectively. Structural analysis highlighted the role of corridor connectivity between these fractures, thus allowing them to be associated with alteration zones. The results demonstrate the potential of MDAs for identifying structural and morphometric patterns in Crystal Cave. However, the use of digital tools, such as color scales and automatic mapping algorithms, requires careful consideration to ensure that the features of interest are mapped correctly.