X-ray computed tomography (CT) scanning is a non-destructive technique that reveals details of 3-dimensional (3-D) structures that cannot be identified by visualization or 2-D X-ray radiography. Industrial CT systems offer great versatility and advantages in analyzing large or dense materials with high X-ray attenuation while providing significantly higher spatial and contrast resolution than common medical CT scanners. Geomaterials, particularly petroleum reservoir rocks and mining ores, have become one of the many applications of industrial CT systems.
Because the CT imagery represented by grey-level values is closely related to density of scanned objects, it is possible to distinguish different minerals with enough density contrast, e.g., quartz/feldspar from carbonate. With advanced image analysis of the CT scanning imagery, much compositional, structural and textural information is quantitatively extracted. Such CT volume imagery is a rich dataset, further processed in dedicated image analysis software.
At spatial resolution of 30 microns for common 1.5-inch-diameter core plugs, features such as small sedimentary structures, natural/induced fractures and bioturbations can be easily identified. This high-resolution digital core is a valuable input for subsequent studies in geoscience and petroleum engineering.