鬼首（おにこうべ）地熱地帯における調査井コアの熱伝導率の温度依存性ならびに原位置伝導熱流量

Oil and geothermal fluids development technologies require detailed information on the dependence of the thermal properties of formations on temperature, pressure, moisture and mineralogy up to the depth of the order of several kilometers. Temperature dependence of the thermal conductivity of 18 dried core samples from U-1 Well having 1100m in depth at the typical hydrothermal reservoir site in Onikobe geothermal area in Miyagi prefecture were studied in the temperature range from 20 to 500°C.The thermal conductivity was measured by the needle prove method at atmospheric pressure under the controlled temperature conditions. The thermal conductivity of the dry core samples, λea, exhibited aθ+b, b and ce-dθ dependence on temperature, θ, macroscopically (where, a, b, c and d>0 are constants). In situ conduction heat flows at the depths from 150 to 1100m were estimated by the above thermal conductivity data and the temperature logging data. The estimated results offered useful information on the geothermal fluid reservoirs through the U-1 Well.