In the KTB field laboratory, thermal conductivity was measured on cuttings material in depth intervals of 10 m and on available drill core material. The results on drill cores give anisotropy information. In general, the maximum thermal conductivity is measured parallel to the strike of foliation and the minimum thermal conductivity perpendicular to that direction. Approximately 250 g of cuttings of the fraction < 2 mm grain are mixed with water. This mixture of cuttings and water is measured (for more details see Pribnow et al. 1992 or Pribnow 1994). This measurement yields the geometric mean of the thermal conductivities in a two-phase mixture model. By measuring the weights of the dry cuttings and the mixture of cuttings and water, PHI is determined knowing the density of the cuttings and water (PHI = 32 %). Usually, the arithmetic mean value from 7 repeating measurements is used.