| Summary: | 碩士 === 國立成功大學 === 地球科學系 === 104 === Porosity is an important property of sandstone owing to the underground resource storage available in this intergranular space. Recently, X-ray computed tomography (XCT) has been widely used to reconstruct the inner structure of rock samples in a non-destructive way. In this study, we employed XCT to investigate the porosity of Darley Dale and Australian sandstone. The large quantity of sliced images on CT was processed using various algorithms in this study and then the porosity for Darley-Dale sandstone and Australian sandstone was discussed after the image processing. 2D (dimensional) image post-processing is a necessary procedure before the reconstruction of a 3D model. Meanwhile, three image processing methodologies, threshold value segmentation, the region growth method and a neural network, were used to distinguish between the voids and solid part of the 2D images. The results demonstrated that the porosity ratio of Darley Dale sandstone is 13.0% using different computing algorithms, which is well-matched to pervious studies. Furthermore, the porosities of Australian sandstone (using the images with the resolution of 9μm and 0.6μm) were found to be 13.1% and 16.1%, respectively, under various image resolutions. Combining the porosity results and based on the above referenced measurements, we conclude that Australian sandstone demonstrated more porous behavior as compared to Darley Dale sandstone.
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