海拉尔盆地地温分布及控制因素研究

根据大量钻孔测温资料和实测热导率资料分析了海拉尔盆地地温分布状况,现今地温梯度变化在2.50℃/100m至4.0℃/100m之间,平均为3.0℃/100m,现今大地热值为42.15~63.86 mWm^-2,平均约为55.00mWm^-2,明显较松辽盆地低,表明海拉尔盆地是一个中温盆地。海拉尔盆地大磨拐河组底面和南屯组底面地温分布具有南高北低的特点。现今地温对油气生成有重要的控制作用,南部凹陷南屯组热演化程度高,普遍处于成熟生油阶段,南屯组是海拉尔盆地的主力生油层位,南部凹陷是海拉尔盆地主要找油区。海拉尔盆地与松辽盆地壳幔结构存在显著的差异。海拉尔盆地现今地温场主要受地壳厚度、基底结构、基底埋深及盆地构造等因素的控制。

STUDY ON TEMPERATURE DISTRIBUTION AND CONTROLLING FACTORS IN THE HAILAR BASIN

The characteristics of temperature distribution in the Hailar Basin was analyzed based on the comprehensive analyses of most data on stratigraphic temperature measurements and thermal conductivity from drilling wells.The results showed that the Hailar Basin was middle geothermal basin with the average geothermal gradient being 3.0℃/100m and the average heat flow being 55 mWm^-2.The present geothermal gradient and heat flow were higher in the southern part and lower in the northern part of the basin.The temperature on subfaces of the Damoguaihe Formation and Nantun Formation was higher in the southern part and lower in the northern part.Present temperature was an important control on oil-gas generation of source rocks.The Nantun Formation in southern depression was in a high stage of geothermal evolution history,with the source rocks being on mature stage of oil generation.As a main source,the Nantun Formation was main sedimentary layer of oil-gas generation,and the southern part of the basin should be main areas for exploration in the Hailar Basin.The crust and mantle structures in the Hailar Basin might be different from that in the Songliao Basin,and the temperature field be controlled by the following factors: crust thichness,basement topography and basin structures.