Thermal conductivity and diffusivity of fine-grained sedimentary rocks

Małgorzata Labus,Krzysztof Labus

doi:10.1007/s10973-018-7090-5

Abstract

Thermal conductivity is an important thermophysical rock property, needed for heat flow determination, deep thermal regime determination, and reconstruction of thermal history of sedimentary basin. It is generally accepted that the thermal conductivity of rocks decreases with increasing temperature and increases with increasing pressure, and the effects of temperature and pressure counteract each other. Although many measurements of thermal conductivity of the igneous and metamorphic rocks have been taken, little attention has been paid to sedimentary rocks and heat flow in sedimentary basins. Samples selected for the investigation, representing sedimentary rocks of aleuritic structure, were collected from boreholes (from deep formation, approx. 3000 m) and outcrops. The mineral composition was determined with the use of TG/DSC analysis, under inert and oxidizing atmosphere. Thermal conductivity measurements were taken with the use of C-Therm analyser, in directions parallel and perpendicular to the bedding in rock. Thermal conductivity of the examined rocks ranges from 0.96 to 6.06 W m−1 K−1 and is strongly dependent on mineral content and bedding direction.

Highlights

Thermal conductivity and diffusivity are important thermophysical rock properties, needed for heat flow determination, deep thermal regime assessment, and reconstruction of thermal history of sedimentary basins [1, 2]
Thermal conductivity and effusivity values allow for the calculation of the thermal diffusivity—a property—that describes how quickly a material reacts to a change in temperature
It is a measure of the temperature change in unit volume of a material caused by the heat that flows in unit time through a body of unit area and unit thickness, under unit & Małgorzata Labus malgorzata.labus@polsl.pl

Summary

Introduction

Thermal conductivity and diffusivity are important thermophysical rock properties, needed for heat flow determination, deep thermal regime assessment, and reconstruction of thermal history of sedimentary basins [1, 2]. The property—thermal effusivity—is required in the analysis of time-dependent conditions. It reflects the ability of a material to exchange heat with the environment, i.e. to store or dissipate the heat. Thermal conductivity and effusivity values allow for the calculation of the thermal diffusivity—a property—that describes how quickly a material reacts to a change in temperature. It is a measure of the temperature change in unit volume of a material caused by the heat that flows in unit time through a body of unit area and unit thickness, under unit

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