海拉尔盆地贝尔凹陷构造演化特征及其对烃源岩的控制作用

Tectonic evolution and the controlling effects on source rocks in Beier Depression,Hailar Basin

贝尔凹陷是海拉尔盆地主要的富油凹陷之一,经历了“三期充填,三期改造”,地质结构复杂。研究构造演化对烃源岩的控制作用具有重要意义。为此,在构造演化特征研究基础上,分析不同演化阶段沉积中心的演变,明确了成熟烃源岩的分布范围。研究表明,贝尔凹陷断陷期发育的3排沉积中心控制了南屯组烃源岩的分布,断拗期盆地快速沉降促进烃源岩成熟,贝西中部洼槽、贝西北洼槽和贝中洼槽南屯组烃源岩已进入成熟生烃阶段,是贝尔凹陷最主要的生烃洼槽。该成果可为下一步贝尔凹陷油气勘探提供依据。

As one of the main oil-rich depressions in the Hailar Basin,Beier Depression has experienced“three periods of filling and three periods of transformation”,with complex geological structures.It is of great significance to study the controlling effects of tectonic evolution on source rocks.Therefore,after studying tectonic evolution characteristics,this paper analyzes the evolution of sedimentary centers in different evolution stages and clarifies the distribution range of mature source rocks.The results show that the distribution of source rocks in the Nantun Formation is controlled by three rows of sedimentary centers developed in the fault depression stage of the Beier Depression.The rapid basin subsidence in the fault depression stage promotes the maturation of source rocks.The source rocks of the Nantun Formation in the middle and north of the Beixi subsag,and the Beizhong subsag have been in the mature stage of hydrocarbon generation,which makes them the main hydrocarbon generation subsags in Beier Depression.The results can provide a basis for the further exploration of oil and gas in the Beier Depression.