北黄海盆地东部坳陷不整合类型及油气成藏模式

Unconformity types and hydrocarbon accumulation models in the eastern depression of the North Yellow Sea basin

北黄海盆地东部坳陷具典型的断-坳叠合性质,中、新生界不整合现象较普遍,地层缺失严重。应用井-震结合方法重新识别和标定了T1、T2、T4、T5和Tg等5个不整合界面,并分析了T5不整合界面主要的不整合类型、平面分布特征、该界面上下主要的岩性配置关系及与该界面相关的油气圈闭类型。研究表明,T5界面主要发育平行不整合、削截不整合和超覆不整合,界面上下岩性组合关系主要为砂-砂、砂-泥和泥-泥型;油气圈闭类型主要有4种:地层上超及下伏的不整合遮挡圈闭,被削截的单斜圈闭,地层超覆及古潜山伴生圈闭和断层与不整合面共同控制的削截、上超圈闭;与不整合相关的油气藏勘探应主要集中在坳陷内的洼陷附近。

The eastern depression in the North Yellow Sea Basin is a typical superimposed basin,and stratigraphic unconformities are greatly developed in Mesozoic-Cenozoic formation with serious deficiencies.The unconformity interfaces of T1,T2,T4,T5 and Tg were identified on the basis of integrating well data and seismic data.We also analyzed the main unconformity type,planar distribution,lithologic features of the T5 interface and the hydrocarbon trap types in connection with T5.The research showed that parallel unconformity,truncation unconformity and overlap unconformity are the main unconformity types of T5,with the sand-sand,sand-mud and mud-clay being the main lithological combination types up and down the T5 interface.Hydrocarbon traps are mainly four kinds,including the stratigraphic overlap and underlying unconformity traps,truncated monoclinic traps,traps associated with stratigraphic overlap and buried hill,and traps associated with the faults and unconformity.Oil and gas exploration related to unconformity in this region should be concentrated in the vicinity of sags within the depression.