Orientational mapping of minerals in Pierre shale using X-ray diffraction tensor tomography

Area of Science:

• Geoscience
• Materials Science
• Physics

Background:

• Shales possess complex mineralogy and multi-scale structural features, challenging conventional analysis.
• Conventional X-ray computed tomography (CT) relies on density differences, proving insufficient for heterogeneous shale interpretation due to sub-resolution features.

Purpose of the Study:

• To apply orientational imaging using X-ray diffraction computed tomography (XRD-CT) for detailed 3D structural analysis of shale.
• To investigate crystallite-orientation distributions and mineral heterogeneity in Pierre shale.

Main Methods:

• Utilized X-ray diffraction computed tomography (XRD-CT) for non-destructive 3D imaging of shale samples.
• Analyzed diffraction-contrast CT data to determine spatial density and orientation of clay minerals.
• Studied scattering properties of highly attenuating inclusions, identifying pyrite and clinochlore.

Main Results:

• Successfully mapped crystallite-orientation distributions within the Pierre shale sample.
• Described the spatial density and orientation of clay minerals, highlighting shale's complex internal structure.
• Identified and characterized highly attenuating inclusions, such as pyrite and clinochlore.

Conclusions:

• XRD-CT is a powerful technique for characterizing complex, heterogeneous materials like shale.
• The study provides a foundation for improved structural descriptions of shales using advanced imaging methods.