松辽盆地北部岩石热导率及其影响因素

Thermal Conductivity of Rocks and Its Influencing Factors in Northern Songliao Basin

本次研究采用瞬态平面源法对松辽盆地北部76个钻孔的263个岩心样品进行了岩石热导率测试。岩心的实测热导率集中在0.58~3.00 W/(m·K)之间,平均为(1.77±0.64)W/(m·K);泥岩、粉砂岩、砂岩、砾岩平均热导率分别为(1.30±0.39)W/(m·K)、(1.89±0.64)W/(m·K)、(1.91±0.37)W/(m·K)、(2.18±0.57)W/(m·K);变质岩、火成岩平均热导率分别为(2.75±0.67)W/(m·K)、(2.70±0.45)W/(m·K)。碎屑岩和凝灰岩热导率整体上呈现出随着埋深和地层年龄的增加而增大的趋势,而砾岩和变质岩变化趋势不明显。分析了压实成岩作用、砂岩的矿物含量和岩石的变质作用对岩石热导率造成的影响。通过饱水测量获得了原位热导率,对岩心的原位导热系数进行了修正。最后建立了松辽盆地北部地层热导率柱,可以为研究区的热流计算、深部地温场建模、盆地热史恢复等提供地层热导率约束。

In this study,the thermal conductivity of 263 drill-core samples from 76 boreholes in the northern Songliao Basin was measured using the Transient plane source methods.All the measured thermal conductivities mainly rang from 0.58 W/m·K to 3.00 W/m·K,with a mean of(1.77±0.64)W/(m·K).The average thermal conductivities of mudstone,siltstone,sandstone and conglomerate were(1.30±0.39)W/(m·K),(1.89±0.64)W/(m·K),(1.91±0.37)W/(m·K)and(2.18±0.57)W/(m·K),respectively;The average thermal conductivities of metamorphic rocks and igneous rocks were(2.75±0.67)W/(m·K)and(2.70±0.45)W/(m·K),respectively.The thermal conductivity of clastic rock and tuff increased with the increase of burial depth and stratigraphic age,while that of conglomerate and metamorphic rock was not obvious.The influence of compaction diagenesis and mineral composition content on thermal conductivity of sandstone was also analyzed and the effect of rock metamorphism on the thermal conductivity was studied.In-situ thermal conductivity of sandstones was obtained via water saturation measurements and the in-situ thermal conductivity of the core was corrected.Finally,the thermal conductivity column of formations in the northern Songliao Basin was established,which can provide stratigraphic thermal conductivity constraints for heat flow calculation,deep geothermal field modeling and basin thermal history restoration.