渤海辽东湾海域JZ25-1S转换带与油气成藏的关系

根据新的三维地震资料解释结果,运用断层的位移-距离分析法,探讨了渤海辽东湾JZ25-1S转换带的变形特征,并分析了转换带与油气聚集的关系。JZ25-1S地区断裂发育,主要为北东走向,平面上呈雁列式排列。倾向相同的辽西1号断层、2号断层和3号断层在叠覆区形成了属于转换斜坡型的JZ25-1S构造转换带,并在斜坡背景上发育有断块构造。JZ25-1S转换带等变形体变换了辽西1号、辽西2号和辽西3号分段断层传递的应力,使断块体在三维空间上保持应变守衡。JZ25-1S转换带对油气聚集成藏的作用主要包括:有利于构造圈闭的形成;控制沉积体系展布;有利于油气运移和改善储层质量。渤海地区同向叠覆型正断层之间发育的转换带是值得探索的有利油气勘探领域。

Relationship between JZ25-1S transfer zone and hydrocarbon accumulation in Liaodongwan offshore of Bohai Bay Basin

Based on the 3D seismic profiles and displacement-distance scaling, the relationship between JZ25-1S transfer zone and hydrocarbon accumulation was analyzed in Liaodongwan offshore of Bohai Bay Basin. There are numerous faults of varying scales in JZ25-1S area, and the NE-trending faults are predominant. JZ25-1S transfer zone is located at the three echelon overstepping faults with the NW-dipping, including Liaoxi-1 fault, Liaoxi-2 fault and Liaoxi-3 fault. According to the features of the faults and their assemblages, the JZ25-1S transfer zone was classified into the relay ramp, where fault blocks were formed. The displacement-distance analysis showed that the displacement transfer and strain conservation of the three segmented faults were accomplished mainly in JZ25-1S transfer zone. JZ25-1S transfer zone had also important influence on the formation of the structural traps, spatial distribution of sedimentary systems and hydrocarbon migration, as well as the reservoir properties in the study area. The transfer zones in the overstepping normal faults with the same dip are the favorable objectives for oil and gas exploration in the offshore part of Bohai Bay Basin.