沙垒田凸起东段曹妃甸11构造大型油田成藏主控因素分析

为了加强对渤海西部海域油气田成藏特征及规律研究,对沙垒田凸起东段曹妃甸11构造大型油田的形成进行了研究。研究表明:1渤中凹陷东南缘(主要烃源岩供给区)沙河街组和东营组烃源岩为曹妃甸11构造大型油田的形成奠定坚实的基础;2NE(北东)向断层两期活动控制油气富集,晚侏罗世-白垩世时期,NE向断层左旋活动分割基底,控制沙垒田凸起东西段构造形态;新近纪时,NE向断层右旋走滑活动,披覆之上的新近系地层形成负花状构造,这不仅控制了东段大型披覆背斜圈闭的形成与展布,而且控制了盖层高点;3新近系优势运移路径最终控制大油田的形成位置。曹妃甸11-1和曹妃甸11-6大型油田都是大面积源岩生成的油气沿多条优势运移路径最后向一个方向聚集而形成的。

Main controlling factors analysis of Caofeidian-11 structure in the eastern Shaleitian salient

In order to make a clear understanding of hydrocarbon accumulation characteristics and regularities in the western Bohai sea area,a study on the formation of Caofeidian-11 structure,a large-scale oilfield,in the eastern Shaleitian salient has been carried out.The study results indicated:1).Source rocks of Shahejie and Dongying formations in the southeast margin of Bozhong sag laid a good foundation for the formation of Caofeidian-11 structure;2).Hydrocarbon enrichment was controlled by NE faults activities in two phases.In late Jurassic-Cretaceous period,the left lateral activities of NE faults split the base and played a control role in structure formation of eastern and western members of Shaleitian salient.In Neogene period,the right lateral strikeslip fault activities of NE faults made the formations from a negative flower structure on the cover,which not only controlled the distribution of large drape anticline but also controlled the high point of the cover.3).The dominant migration pathways in Neocene period controlled the final position of large-scale oilfield.The hydrocarbon in Caofeidian-11 and Caofeidian-16 large-scale oilfields was formed along multiple dominant pathways and finally gathered in one direction.