Thermal conductivity from core and well log data

The relationships between thermal conductivity and other petrophysical properties have been analysed for a borehole drilled in a Tertiary Flysch sequence. We establish equations that permit us to predict rock thermal conductivity from logging data. A regression analysis of thermal conductivity, bulk density, and sonic velocity yields thermal conductivity with an average accuracy of better than 0.2W(mK)-1. As a second step, logging data are used to compute a lithological depth profile, which in turn is used to calculate a thermal conductivity profile. From a comparison of the conductivity-depth profile and the laboratory data, it can be concluded that thermal conductivity can be computed with an accuracy of less than 0.3W(mK)-1 from conventional wireline data. The comparison of two different models shows that this approach can be practical even if old and incomplete logging data are used. The results can be used to infer thermal conductivity for boreholes without appropriate core data that are drilled in a similar geological setting.