北黄海盆地东部坳陷下白垩统层序地层及沉积演化  

Sequence stratigraphy and sedimentary evolution in the Lower Cretaceous of the Eastern Depression in the North Yellow Sea Basin

作　　者：王文娟 张银国[1,2] 陈建文[1,2] 杨艳秋 WANG Wenjuan;ZHANG Yinguo;CHEN Jianwen;YANG Yanqiu(Qingdao Institute of Marine Geology,China Geological Survey,Qingdao 266237,China;Laboratory for Marine Mineral Resources,Qingdao Marine Science and Technology Center,Qingdao 266237,China;College of Marine Geosciences,Ocean University of China,Qingdao 266100,China)

机构地区：[1]中国地质调查局青岛海洋地质研究所,青岛266237 [2]青岛海洋科技中心海洋矿产资源评价与探测技术功能实验室,青岛266237 [3]中国海洋大学海洋地球科学学院,青岛266100

出　　处：《海洋地质与第四纪地质》2024年第3期125-135,共11页Marine Geology & Quaternary Geology

基　　金：中国地质调查局地质调查项目(DD20221723,DD20211353)。

摘　　要：北黄海盆地东部坳陷下白垩统是一套有利的油气勘探储集层,对其精细的地层划分及沉积演化的研究薄弱,制约了对东部坳陷油气勘探前景的深入认识。本文通过对东部坳陷钻井的岩芯观察,测井、录井分析及地震层序的井震标定,认为北黄海盆地东部坳陷下白垩统发育典型的陆相层序,可划分为3个三级层序,从底部向上依次为K_(1)SQ_(1)、K_(1)SQ_(2)和K_(1)SQ_(3)。在钻井上仅可见K_(1)SQ_(1)和K_(1)SQ_(2)两个三级层序,且K_(1)SQ_(2)层序的下降半旋回不完整,只残留该层序的上升半旋回。K_(1)SQ_(1)时期为湖盆断陷伸展期,发育一个完整的湖进—湖退旋回。早期盆地边缘发育河流相,南部主控断裂带发育扇三角洲相,北部缓坡带发育辫状河三角洲相;中后期由于湖平面上升,发育泥岩为主的湖泊沉积;晚期北部缓坡带见小规模辫状河三角洲沉积。K_(1)SQ_(2)时期为湖盆稳定裂陷期,继承了K_(1)SQ_(1)时期的沉积特征并略有收缩。K_(1)SQ_(3)时期为湖盆断陷萎缩期,以发育大范围的河流相沉积为特征。The Lower Cretaceous of the Eastern Depression in the North Yellow Sea Basin is a favorable reservoir for hydrocarbon exploration.However,scarce studies on its fine stratigraphic delineation and sedimentary evolution have restricted the deep understanding of the prospect of hydrocarbon exploration in the eastern depression.Through the core observation,logging and recording analyses,and well-seismic calibration in the eastern depression,it is concluded that the Lower Cretaceous mainly developed 3 third-order sequences,K_(1)SQ_(1),K_(1)SQ_(2),and K_(1)SQ_(3) in bottom-up order.Only 2 third-order sequences,K_(1)SQ_(1) and K_(1)SQ_(2),are visible in the drilling,and the descending half-circle of the K_(1)SQ_(2) sequence is always incomplete,with only the ascending half-cycle of the sequence remaining.The K_(1)SQ_(1) was in the period of faulting extension,and the vertical lithological sequence exhibited a complete depositional cycle with progradation-retrogradation.In the early stage,there were fluvial phases which developed at mainly the basin margins,the fan-delta phases were in the southern rift zone of the basin,and the braided river-delta phase was in the northern slow-slope zone.Due to the uprising of the lake level,mudstone-dominated lake deposits were developed in the middle and late stages.In the advanced stage,small-scale braided river delta deposits developed in the northern slow-slope zone.The K_(1)SQ_(2) was in the period of stabilized rupture,which inherited the depositional characteristics of the K_(1)SQ_(1) period and contracted slightly.The K_(1)SQ_(3) was in the period of faulting abortion,which was characterized by the development of a large area of fluvial phase deposits.

关 键 词：层序特征 沉积相 断陷湖盆 下白垩统 北黄海盆地 

分 类 号：P736[天文地球—海洋地质]