渤海湾盆地惠民凹陷南坡中生界顶部不整合结构特征及成藏作用

渤海湾盆地济阳坳陷惠民凹陷南坡中生界顶部不整合共发育3种类型:削截不整合、超覆不整合和平行不整合,并在纵向上分为3层结构:底砾岩或水进砂体、风化粘土层和风化淋滤带,不整合的每层结构都具有各自的测井响应特征和识别标志。由于每层结构的岩性不同,可形成7种配置关系。通过岩心观察和样品测试分析,曲堤地区不整合风化淋滤带次生孔隙发育。不整合对于研究区内的油气起到了运移和聚集成藏双重作用,因此,开展不整合控藏作用研究,对惠民凹陷隐蔽油气藏的勘探具有重要的指导和实践意义。

Structural features of unconformity and hydrocarbon accumulation on top of Mesozoic,southern slope of Huimin Sag,Jiyang Depression,Bohai Bay Basin

In the southern slope of the Huimin Sag of the Jiyang Depression in the Bohai Bay Basin,3 types of unconformity were found on the top of Mesozoic,including truncation,onlap and parallel ones.The unconformities were divided into 3 layers vertically,including basal conglomerate or transgressed sand body,weathered clay and eluvial zone.Each layer has its own logging response characteristics and identification marks.Due to the different lithology of each layer,7 patterns of lithology configuration were formed.According to core observation and sample test,secondary pores generated in the eluvial zone of unconformity in Qudi area.The unconformity served as the pathway for petroleum migration,and also provided the space for accumulation.The studies of the relationship between unconformity and petroleum accumulation have important academic and practical significances for subtle reservoir exploration in the Huimin Sag.