Thermal conductivity of Cambrian siliciclastic rocks from the Baltic basin

The thermal conductivity of Cambrian siliciclastic rocks, mainly sandstones and siltstones, was studied together with their chemical composition and other petrophysical properties in Estonia, Latvia, and Lithuania. The thermal conductivity is mainly controlled by porosity and rock composition. It was found that the Wiener and layered mixing and geometric mean models approximated best the thermal conductivity vs. porosity relationship of quartz-rich rocks within the measured porosity range (0-30%). The matrix thermal conductivity is positively correlated only with the silica content which reflects the content of quartz, whereas other rock-forming minerals decrease the matrix thermal conductivity. The thermal conductivity of siliciclastic rocks correlates well with porosity-dependent parameters (wet density, apparent resistivity, elastic properties), but has no relation to magnetic properties.