广东惠州地区钻孔岩芯热导率测试与分析OACSTPCD

Thermal conductivity of rocks is an indispensable thermophysical parameter in the fields of terrestrial heat flow study,lithospheric thermal structure analysis,geothermal resources exploration and civil engineering.This paper presents the thermal conductivity measurements of 207 core samples of various rock types from 22 boreholes in Huizhou area of Guangdong Province,South China.The core samples were measured with the TCS optical scanning method.The measured values of thermal conductivity of the 207 samples range from 1.74 to 5.46 W/(m·K)with a mean of(3.25±0.52)W/(m·K).The average thermal conductivity and the number of samples for each sampled rock type are(3.40±0.67)W/(m·K)for 32 pieces of sandstone,(3.15±0.76)W/(m·K)for 11 pieces of conglomerate,(3.12±0.39)W/(m·K)for 63 pieces of limestone,(3.33±0.40)W/(m·K)for 55 pieces of granite,1.84 W/(m·K)for 1 piece of diabase,(3.08±0.27)W/(m·K)for 2 pieces of allgovite,(3.24±0.10)W/(m·K)for 9 pieces of ignimbrite,(2.81±0.26)W/(m·K)for 9 pieces of granite gneiss,metasandstone,(3.38±0.68)W/(m·K)for 3 pieces of metamorphic siltstone,(3.92±0.25)W/(m·K)for 12 pieces of metamorphic sandstone,and(3.48±0.42)W/(m·K)for 10 pieces of marble,respectively.The effect of various factors on the thermal conductivity of rocks was analyzed.Mineral composition is found to be the main factor affecting the thermal conductivity,especially the content of quartz,which is a main diagenetic mineral with high thermal conductivity,is a key factor.The effect is particularly significant with sandstones,of which different quartz contents would result in very much different thermal conductivity.This is the main reason why the rock thermal conductivity measured in this paper is highly consistent with the results previously obtained in Southeast China,but significantly higher than that of the same type of rocks in the Sichuan Basin and Songliao Basin.The results of this study lay an important data foundation for further investigations of geothermal heat flow and lithospheric thermal structure in the study area.