GEOTECNOLOGIAS
URI permanente para esta coleçãohttps://bdc.icmbio.gov.br/handle/cecav/5
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Resultados da Pesquisa
Item An integrated 3D digital model of stratigraphy, petrophysics and karstified fracture network for the Cristal Cave, NE-Brazil(2024-01) Pereira, João Victor F.; Medeiros, Walter E.; Dantas, Renato R.S.; Bezerra, Francisco H.R.; Bruna, Vincenzo La; Xavier Jr., Milton M.; Maia, Rubson P.; Gomes, Daniel D.M.; Silva, Danielle C.C.; Maciel, Ingrid B.Digital Outcrop Models (DOMs) are virtual representations of geological features. Although DOMs are widely used tools in geosciences, their integration with other datasets remains relatively underexplored. We combined a DOM, derived from a photogrammetric survey of a carbonate sequence, with lithostratigraphic, petrophysical (porosity, permeability and uniaxial compressive strength), fracture distribution, and karst dissolution information to compose a single integrated three-dimensional digital model. The study site is one of the entrances of the Cristal Cave (São Francisco Craton, Northeastern Brazil), which has been used as a structural and diagenetic outcrop analog for the Brazilian pre-salt carbonate reservoirs. Data from fracture distributions, measured on the exposed surfaces of the cave, were used to build a Discrete Fracture Network, based on the solution of the stereology inverse problem. Fracture apertures were then modified to generate different scenarios of karstification, thus composing Discrete Fracture and Karst Networks. This integrative approach brought relevant insights into the cave development due to dissolution along fracture clusters. Our methodology offers better geological data handling to build static models to be used in a fluid flow modeling environment, contributing to bridge the gap between geophysics/geology and engineering approaches.- Assessment of a semi-automatic spatial analysis method to identify and map sinkholes in the Carste Lagoa Santa environmental protection unit, Brazil(2021-01-21) de Castro Tayer, Thiaggo; Horta Rodrigues, Paulo CésarSatellite imaging combined with geoprocessing routines is a promising alternative to establish a viable mapping model of specific landscape features and soil use, with high precision, fast results, and low operational costs. The present study examines the employment of a digital elevation model (DEM) combined with geoprocessing techniques for identifying closed depressions in karst landscapes with the objective of mapping potential sinkholes and uvalas within the limits of the Carste Lagoa Santa Environmental Protection Unit, located in the state of Minas Gerais, Brazil. The proposed method consists of using geoprocessing routines combined with DEMs, topographic analysis, individual points of elevation, and mathematical operations between rasters. To accomplish that, SRTM (Shuttle Radar Topographic Mission) data/images were used to extract contour lines and individual elevation points to identify depressions, delimit their edges, and obtain morphometric data referring to the area, perimeter, and their circularity index. The results were satisfactory, allowing the detection of 1076 depressions within the study area. The results were also analyzed for special morphological cases and circularity patterns and compared with a previous study. Field campaigns allowed the partial validation of the method, which proved to be a viable alternative for preliminary and extensive scale mapping of these important karst recharge features.
Item Assessment of a semi-automatic spatial analysis method to identify and map sinkholes in the Carste Lagoa Santa environmental protection unit, Brazil(2021-01-21) Tayer, Thiaggo de Castro; Rodrigues, Paulo César HortaSatellite imaging combined with geoprocessing routines is a promising alternative to establish a viable mapping model of specific landscape features and soil use, with high precision, fast results, and low operational costs. The present study examines the employment of a digital elevation model (DEM) combined with geoprocessing techniques for identifying closed depressions in karst landscapes with the objective of mapping potential sinkholes and uvalas within the limits of the Carste Lagoa Santa Environmental Protection Unit, located in the state of Minas Gerais, Brazil. The proposed method consists of using geoprocessing routines combined with DEMs, topographic analysis, individual points of elevation, and mathematical operations between rasters. To accomplish that, SRTM (Shuttle Radar Topographic Mission) data/images were used to extract contour lines and individual elevation points to identify depressions, delimit their edges, and obtain morphometric data referring to the area, perimeter, and their circularity index. The results were satisfactory, allowing the detection of 1076 depressions within the study area. The results were also analyzed for special morphological cases and circularity patterns and compared with a previous study. Field campaigns allowed the partial validation of the method, which proved to be a viable alternative for preliminary and extensive scale mapping of these important karst recharge features.