高邮凹陷有效砂岩输导层分布及控藏作用

Effective sand carrier beds distribution and its reservoir forming control in Gaoyou sag

有效砂岩输导层是指经历过油气运移的砂层,据油气显示和油气包裹体识别有效砂岩输导层,同时结合烃源岩的分布、砂层的空间位置以及构造背景来分析有效砂岩输导层的分布。结果表明:高邮凹陷有效砂岩输导层具有分带性和分层性的分布特征:在北部斜坡带,阜一段主要分布在其顶部砂层段,具'广而薄'的特点,阜三段主要分布层段从内坡带向外坡带逐渐抬升,内坡带全段分布,而在中、外坡带集中在中上部的砂层段;在断裂带,戴一段主要分布于阜四段有效烃源岩分布区内,而戴二段分布较局限,主要沿油源断层分布,具有'窄而厚'的特点。高邮凹陷有效砂岩输导层的分布受沉积相带、构造背景、有效烃源岩的分布以及源岩与输导层接触关系、油源断层、区域盖层和辉绿岩的侵入等多种因素控制。有效砂岩输导层控制着高邮凹陷斜坡带油藏的分布位置和层位,有效砂层的顶面形态控制了油气优势运移路径,有效砂岩输导层、有效烃源岩和输导动力场的优势配置控制油气富集。

Effective sand carrier beds are the sand layers experienced oil and gas migration.The transported hydrocarbon can be identified by the hydrocarbon show and fluid inclusions.Meanwhile,the distribution characteristics of effective carrier beds were studied by the distribution of hydrocarbon source rocks,the spatial location of the sand and tectonic setting.The results show that the distribution of the effective sand carrier beds is characterized by zonation and lamination in Gaoyou sag.The effective sand carrier beds of slope zone are E1f1 and E1f3.The E1f1 carrier beds are ＂wide and thin＂,mainly distributed in the uppermost part of sand layers,while for the E1f3,they are characteristically distributed throughout the inner slope zone,and gradually become limited on the upper part of sand layers in the middle and outer slope zones.The effective sand carrier beds of the fault zone,E2d1 and E2d2 layers are ＂narrow and thick＂.The E2d1 effective sand carrier beds are distributed mainly in the distribution region of effective source rock of E1f4,while the E2d2 effective sand carrier beds are mainly in occurrence along the source faults.The distribution of effective sand carrier beds in Gaoyou sag is multi-controlled by sedimentary facies,structure,distribution range of effective source rock,contact relationship with source rocks,faults connected to source rocks,regional seal,diabase invasion.The effective sand carrier beds affect the hydrocarbon distribution position and layer.The shape of top surface of the effective sand carrier beds controls the dominant migration pathway in slope area of Gaoyou sag.Accordingly,it is proposed that the rational combination of effective sand carrier beds together with source rocks and dynamic field controls the hydrocarbon distribution in the slope zone of Gaoyou sag.