海塔盆地中部主要断陷带早期和晚期油气富集的主控因素

为了厘清海塔盆地油气富集的主控因素及富集规律，通过油藏解剖、油气富集条件空间配置关系和油气形成时期的研究，将海塔盆地中部主要断陷带已聚集的油气按成藏形成时期分为早期、晚期2种类型，早期油气主要分布在基岩、铜钵庙组和南一段，晚期油气主要分布在南二段和大磨拐河段。早期油气分布广，明显多于晚期油气。早期油气富集的主控因素有:①南一段油源区分布控制着早期油气分布范围；②早期伸展断裂控制着早期油气富集的部位；③扇体沉积砂体为早期油气聚集提供了有利储集体。晚期油气富集的主控因素有:①油源分布区域控制着晚期油气分布范围；②长期发育断裂控制着晚期油气富集的部位；③反转构造上形成的各类圈闭为晚期油气富集提供了有利场所。

Main Controlling Factors of Early and Late Hydrocarbon Accumulation in Main Fault Depression Zones of Central Haita Basin

To clarify the main controlling factors and rules of Haita Basin hydrocarbon accumulation, after in-depth study on the reservoirs, the spatial matching of hydrocarbon accumulation conditions and formation periods, it is found that hydrocarbon accumulated in the main fault depression zones of central Haita Basin can be divided into two types, which are hydrocarbon formed in early period (early hydrocarbon) that mainly distributed in K₁n1, K₁t and basement rock, and hydrocarbon formed in late period (late hydrocarbon) that mainly distributed in K₁d and K₁n2. The early hydrocarbon is widespread and more than the late hydrocarbon. Factors that controlled the accumulation of early hydrocarbon are: the distribution of K₁n1 oil source area controls the range of early hydrocarbon; early extensional faults control the position where early hydrocarbon accumulated; and sandbody of the fan provides favorable location for early hydrocarbon to accumulate and form reservoir. Whereas factors that controlled the late hydrocarbon are: oil source area distribution controls the range of late hydrocarbon; long period developed faults control accumulation position of late hydrocarbon; and inverted tectonics provide trap structures for the late hydrocarbon to accumulate.