Sichuan Basin Xujiahe Formation Shale Rock 3D Microstructures

Full description

The data is related to a sample from a Triassic shale oil reservoir, the fifth member of the Xujiahe Formation from the Sichuan Basin in southern China. The data set include the following:
X-ray projection images, plus flate-field and dark-field images
Reconstructed CT slices
DCM characterized and threshold segmentated composition and porosity images
Lineage: Data acquired at Shanghai Synchrotron Radiation Facility (SSRF) BL13W beamline by Yudan Wang of SSRF. Sensor was PCO-2000 CCD optically coupled to a scintillator with an Optique Peter camera, with an effective pixel size of 0.74 microns. Tomographic datasets were acquired at 20keV and 30keV. 1080 views were acquired for each dataset over a 180 degree rotation with 3s exposure per view. Flat-field images were obtained with X-ray beam turned on with the sample not in the FOV for every ten degrees during the sample scanning. The dark-field images were acquired after the sample scan with the X-ray beam turned off. Sample to detector distance was 23cm to enhance phase-contrast to improve signal to noise ratio. Data were processed and reconstructed using the X-TRACT software. Data was pre-processed with background correction, and phase-retrieval was used to eliminate the phase-contrast effect on reconstructed linear absorption coefficients. Parallel beam reconstruction was carried out using a filtered-back-projection algorithm.
The Trim-CT slices have been analysed using the DCM software. The CT slices are analysed using the DCM linear optimisation module. The input density of quartz and calcite are 2.65g/cm3 and 2.71g/cm3, respectively. By averaging over the 600 slices, the calculated void volume fraction (porosity) is 6.4%, the volume fraction for the calcite phase is 76.9%, and for the quartz phase it is 16.7%.
The Trim-CT slices of 30keV have been analysed using conventional segmentation method. For purpose of comparison with the DCM method, a threshold value is selected so that it is producing a similar overall porosity as from DCM. By averaging over the 600 slices, the calculated void volume fraction (porosity) is 6.3%.