The effects of particle sorting and compaction pressure on spatial distribution of porosity of synthetic quartz cores were investigated. A high-resolution X- ray computed tomography (CT) system with a microfocus X-ray source was used to acquire CT scans of 12 cores. The cores consist of a mixture of quartz powder and different proportions of quartz granulates ( with a particle size range of 0.126 to 0.210 mm) that were compacted at 20.68MPa (3,000 psi), 27.58MPa ( 4,000 psi), and 34.47MPa ( 5,000 psi) pressures. Calibration of core density was carried out according to the ASTM standard procedure. Computer algorithms were developed to calculate local porosity (phi) values, producing about 15 million phi values per core. The results of the analysis were represented by histograms and qualitatively compared with capillary pressure versus brine saturation measurements. As a result of changing the particle sorting (i.e., using a wider range of particle sizes), the standard deviation of the porosity distribution increases for the cores compacted under the same pressure. There were mixed trends of the effects of compaction pressure on porosity. However, they are qualitatively consistent with the capillary pressure measurements.