焼岳地熱地帯における調査井コアの熱伝導率の温度依存性について

抄録

Hot Dry Rock technology requires a thorough knowledge of the variation of the thermal properties of rocks up to depth of the order of five kilometers. Temperature dependences of the thermal conductivity of 42 core samples from three test wells having 300 m depth at the field test site for the HDR technology in Yakedake geothermal area are presented in the temperature range 20-500°C. They are measured by a needle probe method. The thermal conductivity of the core sample exhibits θ¹, θ⁰ and θ^-1 dependences on temperature, θ, macroscopically. However, they are more complicatedly classified into θ¹+θ⁰, θ^-1+θ⁰and θ^-1+θ¹ dependences on θ in addition to above the three dependences, microscopically. In situ thermal conductivities of the rocks and terrestrial conduction heat flows at depths 110, 200 and 300 m in one of the test wells, HY well, are estimated by the obtained data.