Characterization of rock
NGI uses various advanced techniques for characterization and visualisation of rock samples and fractures at various scales, prior to and after geomechanical testing.
- CT scanner for 2D representation (vertical and horizontal cross-sections) and 3D volume representation of cores and plugs
- Photogrammetry to visualize fracture surface topography, employing measurements made in two or more photographic images taken from different positions (based on stereoscopy).
- Optical Microscope for thin section analysis (grain scale)
- Scanning Electron Microscope (SEM) for sub-micro scale visualization (using SEM at University of Oslo)
- CT-scanner: for inspection of core quality or heterogeneities before testing, aperture/roughness distribution, evaluation of failure mechanisms after testing
- Photogrammetry: for visualisation of fracture topography and roughness as 3D surfaces or 2D fracture profile
- Optical Microscope: for mineralogy and texture of matrix framework and shear zones.
- SEM for microstructures and mineralogy of the fracture slickensides and lineations.
Figure: CT 2D cross section (left), visualisation of fracture aperture (middle) and photogrammetry of fracture surface roughness for a 3D surface and along a line (right)