二连盆地白音查干凹陷古地温与油气生成的关系  

Relationship Between Paleogeotherm and Hydrocarbon Generation in the Baiyinchagan Depression,Erlian Basin

作　　者：刘春晓[1,2,3] 张晓花[4] 

机构地区：[1]中国科学院海洋研究所海洋地质与环境重点实验室,山东青岛266071 [2]中国科学院研究生院,北京100049 [3]中国石化中原油田分公司物探研究院,河南濮阳457001 [4]中国石化中原油田培训中心,河南濮阳457001

出　　处：《山东科技大学学报（自然科学版）》2011年第3期12-20,共9页Journal of Shandong University of Science and Technology(Natural Science)

基　　金：国家自然科学基金项目(40701133);中国博士后科学基金项目(20080440829)

摘　　要：白音查干凹陷的热史研究还处于初级阶段,对补测数据进行了古地温恢复、剥蚀厚度等方面的详细研究,得到以下结论:①现今凹陷地温梯度为3.06℃/100 m,低于二连盆地平均水平3.50℃/100 m,且地温梯度随构造部位的不同而各异。②洼陷镜质体反射率最大,热演化程度最高,具备了大规模生烃的条件,其中阿二段是凹陷生烃的主力层位。③古地温恢复的结果是凹陷的古地温梯度为5.21℃/100 m,明显高于现今地温梯度。④赛汉塔拉组沉积以后,凹陷遭受不同程度的剥蚀,剥蚀厚度从850 m到3 970 m不等,生油门限变浅。新生代以来地温梯度减小,生油过程中断。⑤凹陷地质背景决定了白音查干凹陷生油层大部分处于低成熟阶段,断裂带处于凹陷油气运移的指向处,大套地层遭受剥蚀,盖层及油气封堵条件遭受破坏,使低成熟—高成熟原油遭受降解氧化,形成次生降解稠油。The study on the thermal evolution history of Baiyinchagan depression is still in preliminary stage.In this paper,Some supplementary observed data were analyzed in detail in such aspects as paleogeotherm restoration,erosion thickness,etc.The conclusions are as follows： ①Current geothermal gradient in this depression is 3.06 ℃ /100 m,lower than the average level of 3.50 ℃/100 m in Erlian basin and the temperature gradient varied with structure locations.②Both the vitrinite reflectance and thermal evolution level in this area are the largest and higest than other part of the basin respectively.These enabled the large-scale hydrocarbon generation possible in which the Aerduan is the main hydrocarbon generative formation.③The recover paleogeothermal gradient is 5.21 ℃/100 m,significantly higher than the present one.④After Saihantala sedimentation,this depression underwent multiple erosions in different levels,the denudation thickness was ranging from 850 m to 3 970 m,thus the threshold depth of oil generation became shallow.The geothermal gradient has decreased since Cenozoic and the process of generation was interrupted.⑤Restricted by the geological background,most source rocks of Baiyinchagan depression are in low-mature stage.Fracture zone lies on the pathway of hydrocarbon migration,many strata were eroded and the cap rock and sealing conditions were destroyed.Consequently,the low-mature and high-mature crude oil were subjected to oxidation and degradation,forming secondary degradation heavy oil.

关 键 词：白音查干凹陷 古地温 热史 油气藏 油气生成 

分 类 号：TE122.1[石油与天然气工程—油气勘探]