北大西洋段演化特征和海相烃源岩研究

Tectonic Evolution Characterize of North Atlantic and Marine Source Rock Study

北大西洋段构造演化可以划分为3个阶段,分别为二叠纪陆内裂谷阶段、三叠纪—侏罗纪同裂谷和热沉降阶段、白垩纪至今被动陆缘阶段。被动陆缘阶段包括两个演化分支,"西支"代表格陵兰板块和北美板块拉开形成的巴芬湾盆地和西格陵兰盆地,"东支"为格陵兰极块和欧洲板块拉开而发育的法罗设得兰、挪威陆架盆地和东格陵兰盆地。晚侏罗世—早白垩世是北大西洋段沉积盆地的重要成烃期,发育过渡期局限海相烃源岩、裂谷期局限海相烃源岩和被动陆缘期开阔海相烃源岩3种类型的烃源岩,其中局限海相烃源岩有机质丰度高,生烃潜力大。依据烃源岩发育特征、平面分布并结合盆地的勘探程度等因素,综合分析指出了勘探潜力大的盆地是挪威陆架盆地和法罗设得兰盆地,有较大远景资源规模的是东格陵兰盆地。

Tectonic evolution of North Atlantic can be divided into three stages - the Permian intracontinental rift stage, the Triassic-Jurassic syn-rift and thermal subsidence stage and the Cretaceous passive continental margin stage. The passive continental margin stage includes two evolution branches. The ＂western branch＂ represents Baffin Basin and West Greenland Basin formed from separation between Greenland plate and North America plate while the ＂eastern branch＂ includes Faro Basin, Norwegian Shelf Basin and East Greenland Basin formed from separation between Greenland Polar plate and European plate, The Late Jurassic - Early Cretaceous period is the important hydrocarbon sourcing stage for the North Atlantic sedimentary basin with three types of source rock developed - restricted marine source rock of the transition period, restricted marine source rock of the rift stage and open marine source rock of the passive continental margin stage, of which restricted marine source rock is the most abundant in organic matter and highest in hydrocarbon sourcing ability. Based on development characteristics of source rock, horizontal distribution and exploration degree of the basins, it is pointed out that Norwegian Shelf Basin and Faro Basin have great potential for exploration while East Greenland Basin shows a large-scale prospective reserve.