Hyperspectral imaging (HI) is a method of observing and enhancing geological rock properties that are not readily apparent visually. Originally developed for the mining industry, HI uses a combination of short-wave infrared light (SWIR) and long-wave infrared light (LWIR) to create a visual ‘map’ of the minerals on the surface of a core that respond to reflectance principles. HI, which requires no special preparation other than that the core be slabbed, clean, and dry, can be rapidly obtained and provides mineralogical and chemical results related to various energy emitted in wavelength spectrum by either halogen bulb reflectance (short-wave quantification) or heat reflectance spectra (long-wavelength quantification).
We collected hyperspectral core imaging data of the Marathon 1 Austin Chalk Robert Todd core in central Louisiana to obtain detailed, high-resolution mineralogical and textural information and investigate the application of hyperspectral imaging as an integrative tool.
Digital HI-derived single mineral curves calibrated to X-ray diffraction (XRD) were imported as curves to display mineralogical variations with depth alongside overlays showing the textural relationships of the mineralogical assemblages, rock typing models, X-ray fluorescence (XRF) data, TOC data and rockmechanics data. The integration of the hyperspectral data with core description, SEM, thin-section, XRF, XRD, rock mechanics and TOC data illustrates relative differences in carbonate volumes that identify Milankovitch cycles, delineates fabric via variations in mineralogical composition of fine laminae, identifies relatively Sr-rich intervals that cannot be distinguished visually, reveals a relationship between total organic content and mineralogy, and facilitates upscaling of SEM and thin-section date to the core scale.