The characteristics of rock thermal conductivity of coal measure strata and their influence on geothermal field in Huainan-Huaibei coalfield

With the increase of coal mining depth, the problem of high temperature in mine becomes more and more obvious. Therefore, it is necessary to study the geothermal field in mining area. Based on the results of thermal conductivity of tested 127 rock samples of coal measure strata in Huainan-Huaibei coalfield and combining the previous measured data in the region, this paper reported the parameters and the characteristics of rock thermal conductivity in Huainan-Huaibei coalfield comprehensively and analyzed the influencing factors of thermal conductivity from different aspects. The results showed that the thermal conductivity of coal measure strata in Huainan-Huaibei coalfield ranges from 0.37 W/(m·K) to 4.36 W/(m·K) and the average is 2.54 W/(m·K). The correlation between the thermal conductivity and lithology, buried depth, stratigraphic age and density is significant. The thermal conductivity of sandstone is generally greater than that of mudstone and coal. There is a positive correlation between thermal conductivity and depth, density. The differences of thermal conductivity of rocks have a big influence on the regional geo-temperature gradient, poor heat conductivity of unconsolidated layers and coal seam tends to cause ground temperature anomaly, and the thicker overlying unconsolidated layers, the higher ground temperature.