Research on the anisotropy of thermal conductivity of rocks in Songliao basin, China

Abstract

Understanding the thermal conductivity of rocks is crucial for the development and utilization of geothermal reservoirs. In order to study the anisotropy of thermal conductivity of rocks, the thermal conductivities of granite, rhyolite, sandstone and mudstone in Songliao basin were tested, and the microstructure, mineral composition and content of the samples were analyzed by means of polarizing microscope and X-ray diffraction. The thermal conductivities of different rock types parallel to and perpendicular to the structural plane were obtained, and the anisotropic factors of the thermal conductivity of rocks in the songliao basin were calculated. The thermal conductivity of rocks with a high proportion of layered minerals is generally anisotropic. The thermal conductivity anisotropy of syenogranite, rhyolite and mudstone in Songliao basin is not obvious, and the variation range of anisotropic factors were 1.01–1.30, 1.02–1.10, and 0.87–1.11 respectively. The average anisotropy factor of thermal conductivity of granodiorite and sandstone is 1.12 and 0.89 respectively, indicating that these two kinds of rocks have anisotropy. Finally, according to the relationship between rock type, microstructure, mineral composition and anisotropy of thermal conductivity, the modified equation of anisotropy of rock thermal conductivity of Songliao basin was proposed.