SEISMIC VELOCITY, DENSITY, THERMAL-CONDUCTIVITY AND HEAT-PRODUCTION OF CORES FROM THE KTB PILOT HOLE

This paper presents a compilation of about 50000 petrophysical data me asured on core samples from the Continental Deep Drilling Project (KTB ) of the Federal Republic of Germany. The pilot hole provided a quasi- continuous core profile, 4000 m in length, for measurement of several petrophysical parameters and analysis of quantitative mineral composit ions, with sampling rates between 0.5 and 5 m. The variances of the da ta within the lithological units, which at KTB are mainly gneisses and metabasites, are greater than the experimental errors and are influen ced by rock fabric, possible insitu variations, e.g., pressure and wat er content, or the small-scale mineral composition. High space resolut ion measurements of velocity and density provide an example how relaxa tion effects, heterogeneity, and anisotropy can influence the petrophy sical data. Density, thermal conductivity and the content of uranium, thorium and potassium are related to the contents of quartz and amphib ole. Porosity and sound velocity, measured under normal conditions, do not match those expected from consideration of the mineral compositio n. Petrophysical properties measured in the field are normally represe ntative of larger volumes than those measured in the laboratory. The e xtensive petrophysical investigations on KTB-cores provide variances t hat are related to the representative rock units and could thus help a ddress this scaling problem. The variances could, for example, be used for constructing velocity profiles or input parameters for modelling.