X-Ray Diffraction (XRD) – Whole Rock and Clay Mineralogy


Weatherford Laboratories’ X-ray diffraction (XRD) service is the industry standard for providing direct measurement of formation mineralogy through an analysis of core and drill cuttings. These high-quality data sets identify the relative amounts of bulk (whole rock) and clay minerals within the formation.

XRD analysis is used to identify crystalline compounds (mineral) based on their crystal structure. Each compound gives a unique pattern of diffraction peaks. A pattern from an unknown sample can be compared to standard patterns for qualitative and quantitative identification.

Employing the spray drying technique for bulk sample preparation eliminates preferred orientation. XRD patterns from spray-dried samples are extremely reproducible.

  • Provides bulk mineral composition and relative abundance of clay species, accurate to 3 weight %

  • Provides the percentage of smectite interlayers in the mixed-layer illite/smectite clays

  • Kubler Index: calculation of illite crystallinity to determine thermal maturity

  • Weight % XRD data can be converted to volume % by using average mineral densities and integrating with TOC weight % values

  • Identifies crystalline composition of various unknown minerals, such as scale, produced material, or filter samples


  • Increase accuracy of lithological assessments and more informed stratigraphic correlations

  • Direct knowledge of variations in sample mineralogy, which may facilitate optimal choice of drilling, completion, and stimulation fluids

  • Screens for the most brittle zones for vertical completions or lateral drilling targets

  • Improved log calibration by allowing grain density and illite crystallinity calculation (for thermal maturity assessment)

In addition to innovative technology, Weatherford Laboratories has industry leading experience in mineralogical interpretation.