Investigation of image segmentation effect on the accuracy of reconstructed digital core models of coquina carbonate
| Autor: | Lai Fu-Qiang, Wang Hai-Tao, Zhang Jin-yan, Wang Li |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Materials science
010504 meteorology & atmospheric sciences Computer simulation Petrophysics Geometry Image segmentation 010502 geochemistry & geophysics 01 natural sciences Grayscale Physics::Geophysics Geophysics Computer Science::Computer Vision and Pattern Recognition Percolation Segmentation Porous medium Porosity 0105 earth and related environmental sciences |
| Zdroj: | Applied Geophysics. 17:501-512 |
| ISSN: | 1993-0658 1672-7975 |
| DOI: | 10.1007/s11770-020-0846-2 |
| Popis: | Digital core models reconstructed using X-ray tomography (X-CT) enable the quantitative characterization of the pore structure in three dimensions (3D) and the numerical simulation of petrophysics. When the X-CT images accurately reflect the micro structures of core samples, the greyscale threshold in the image segmentation determines the accuracy of digital cores and the simulated petrophysical properties. Therefore, it is vital to investigate the comparison parameter for determining the key greyscale threshold and the criterion to describe the accuracy of the segmentation. Representative coquina digital core models from X-CT are used in this work to study the impact of grayscale threshold on the porosity, pore percolation, connectivity and electrical resistivity of the pore scale model and these simulations are calculated by Minkowski functions, component labeling and finite element method, respectively, to quantify the pore structure and simulate electrical resistivity. Results showed that the simulated physical properties of the digital cores, varied with the gradual increase of the greyscale threshold. Among the four parameters related to the threshold, the porosity was most sensitive and chose as the comparison parameter to judge the accuracy of the greyscale threshold. The variations of the threshold change the micro pore structures, and then the electrical resistivity. When the porosity of the digital core model is close to the experimental porosity, the simulated porosity exponent matches the experimental porosity exponents well. The good agreement proved that the porosity is the critical comparison parameter to describe the accuracy of image segmentation. The criterion is that the porosity of the digital core after segmentation should be close to the experimental porosity. |
| Databáze: | OpenAIRE |
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