Far-infrared investigation of kaolinite and halloysite intercalates using terahertz time-domain spectroscopy

Simultaneous Determination of Organic Distribution and Content in Oil Shale by Terahertz Imaging

“…Changes in the component relate to changes in n , therefore allowing us to determine the dielectric properties of the oil shale. At the submillimeter length scale, mineral components are typically homogeneous in the direction of the bedding plane; however, organics with a softer texture always exhibit an amorphous appearance in the reservoir pores, and as a result, the organic distribution on the oil shale surface is always heterogeneous. , Since organics have a much smaller dielectric constant compared to the sedimentary matrix itself, the diversity of the THz amplitude can be related to the organic content-dependent n . , Therefore, the organic contained areas can be easily recognized by THz imaging. For example, the black and purple areas in Figure a represent a lower THz reflectivity compared with the red areas, indicating a higher local concentration of organic matter.…”

“…Fourier-transform infrared spectroscopy, Raman spectroscopy, mass spectrometry, and nuclear magnetic resonance were used to characterize the properties of oil shale. − Owing to the location between far-infrared and millimeter-wave spectrum bands, terahertz (THz) spectroscopy has recently emerged as an efficient tool in various aspects because of its unique advantages. − The response of a THz wave is strongly related with the materials’ dielectric properties . To date, THz technology has been utilized to evaluate the dielectric properties of various minerals and rocks, including kaolinite, montmorillonite, halloysite, sandstone, limestone, marble, etc., showing different quantitative relations between the mineral’s content and THz parameters. − In the study of oil shale, relations were built between THz absorption and the oil content in semicoke, which could be a significant indicator of pyrolysis process optimization. − The anisotropic optical responses of oil shales were measured by THz spectroscopy, revealing a refractive index ( n ) anisotropy associated with the bedding planes. Increasing organic content has promoted the anisotropic degree of oil shale, and a linear correlation can be built between the n anisotropy and the oil yield, providing an alternative parameter for oil yield characterization .…”

Layer Caused an Anisotropic Terahertz Response of a 3D-printed Simulative Shale Core

“…17 At present, THz-TDS has been applied to investigating the optical properties of marble, sandstone, and limestone. 18 The dielectric properties of montmorillonite clay, 19 micaceous clay, 20 kaolinite, halloysite, 21 and clay-based polyamide nanocomposite films were measured at the THz region. 22 Meanwhile, the THz technique has also been employed to study the anisotropic response of materials.…”

Discriminating the Mineralogical Composition in Drill Cuttings Based on Absorption Spectra in the Terahertz Range

“…To date, THz spectroscopy has been applied for the investigation of the optical properties of marble, sandstone, and limestone. 30 The optical constants and dielectric properties of montmorillonite clay, 31 micaceous clay, 32 kaolinite, halloysite, 33 and clay-based polyamide nanocomposite films 34 were measured in the THz region. Nevertheless, those studies were focused on the optical characteristics of rocks and minerals, and the relationship between rock properties and THz parameters has not been analyzed.…”