In order to assess the exact mineralogy of rock samples, we offer X-ray diffraction (XRD) analyses (bulk rock and clay mineralogy), which are performed in-house. XRD analyses can be done on so-called whole rock samples, or on the clay fraction (<2 µm) only. The data is interpreted and presented both in table format as well as annotated XRD diffractograms. This analysis often proves to be extremely useful for detailed reservoir characterisation, for instance if possible reservoir impairment by swelling clay minerals is suspected.