| dc.description.abstract | Rock thermal conductivities are one of the essential parameters for determining crustal heat flows. If drill cores are not retrieved from boreholes, no direct laboratory measurements of thermal conductivity can be made for subsurface rocks and sediments. In this case, petrophysical properties obtained from well logging can be used to determine thermal conductivities. In this study, I firstly establish empirical relations between thermal conductivities and three petrophysical properties: matrix density, porosity, and sonic slowness, from well-log measurements at the same depth of dry rock samples. We then apply these empirical equations to borehole well-log data to obtain a continuous thermal conductivity profile for some desired rock formations. Rock samples from 6 boreholes of Cretaceous to Miocene sandstones and shales in the Tainan Basin, offshore SW Taiwan, and Pleistocene sandstones at the Hushan Reservoir, Yunlin County, are measured for determining thermal conductivity (λ), matrix density (ρma), porosity (φt) and sonic slowness (Sp). A regression analysis of the measurements yields a best fit (e.g., rms of 0.08W(mK)-1) of a linear trend line, and this trend is then applied to well-log data with continuous measurements of matrix density, porosity and sonic slowness to obtain a continuous thermal conductivity profile for rocks drilled in a particular borehole. The proposed empirical linear relations between thermal conductivity and matrix density, porosity, and sonic slowness can be readily used to obtain thermal conductivities from well-log data. | en_US |