海拉尔盆地贝尔凹陷潜山油气成藏特征

CHARACTERISTICS OF HYDROCARBON POOLING IN BURIED HILL OF BEIER SAG IN THE HAILAER BASIN

通过对海拉尔盆地贝尔凹陷上侏罗统布达特群潜山源岩、盖层和内部断裂系统等成藏地质因素的动态和静态研究认为,生油盖层、断层和裂缝、生烃凹陷、源岩断裂是该潜山油气成藏的四大主控因素:有效的区域性封盖层大面积呈中等级别的封盖,其主要分布在贝尔凹陷的中部和南部的二级构造带上;大量继承性的源岩断裂和裂缝与烃源岩的生排油时期在时间上匹配良好,并具有多期次的开启和闭合周期,在很大程度上决定了油气成藏的储集性能,并成为了油气成藏的主要运移路径和储集空间;生烃凹陷的位置则控制着油气藏的空间分布,其空间分布又决定了布达特群古潜山"新生古储、多源一储"的成藏模式。结论指出:盖层封盖条件较好的、油源附近的继承性源岩断裂区域应是下一步油气勘探的有利地区。

Dynamic and static studies of the source rocks,seals and internal fault systems of the Upper Jurassic Budate Group buried hill in Beier sag of the Hailaer basin show that seals,fault-fractures,hydrocarbon kitchens and source rock-rooted faults are the four main controlling factors of hydrocarbon pooling.The large effective regional seals have moderate sealing capacity and are mainly distributed in the central and southern secondary structural zones in Beier sag.The large amount of source rock-rooted faults and fractures with good inheritance have favorable timing with hydrocarbon generation and expulsion,and have experienced multiphase opening and closing,thus determined and became,to a large extent,the major migration pathways and reservoir space.The locations of hydrocarbon kitchens control the spatial distribution of the reservoirs and their spatial distribution determines the unique patterns of hydrocarbon pooling in Budate Group,i.e.,'hydrocarbons generated by younger source rocks accumulate in older reservoirs and multiple source rocks contribute to one reservoir'.It is concluded that areas that have relatively good sealing conditions,are close to the hydrocarbon kitchens,and have source rock-rooted faults with good inheritance are favorable for future exploration.