Numerical Simulation of Internal Factors that Influence the Thermal Conductivity of Rock

Rock thermophysical properties are the basic parameters that constrain the temperature field, thermal evolution, and thermal regime of the lithosphere. The petrofabric is the internal factor that most directly affects the thermal conductivities of rocks. In this study, we used the finite-element method to simulate the influence of major petrofabric characteristics such as pore size, fracture angle, and composition arrangement on the thermal conductivity. The results show that at the 1 % porosity there is no obvious relationship between pore size and thermal conductivity. However, the contact thermal resistance between grains is different in rocks with different pore sizes or grain sizes. Further, the angle between a fracture and the direction of heat flow has an obvious effect on the thermal conductivity of a rock, and the thermal conductivity decreases as this angle increases. It is thus necessary to pay attention to this angular relationship when modelling the effective thermal conductivity of rock with cracks developed. In addition, the arrangement of components in rocks affects both the thermal conductivity and the response of the thermal conductivity to temperature. We expect the present results to be helpful in understanding quantitatively the influence of these factors on the thermal conductivity of rock and to provide a valuable reference for experimental studies of rock thermal conductivity and strata thermal conductivity modelling.