【摘要】 目前陆相湖盆构造活跃期沉积的层序地层研究比较成熟,而对于其萎缩期的准平原沉积的层序地层研究多处于探索阶段。以黄河口地区新近系明下段(湖盆萎缩期沉积)为例,以控制层序发育的古气候变化为线索,分析了古气候变化与湖平面变化的关系,研究了古气候变化引起的孢粉组合、藻类丰度及分异度、粘土矿物成分和含量以及测井GR值的变化特征,并以此作为层序划分的依据;在湖平面变化的基础上,通过基准面变化和A/S变化分析,将明下段层序划分为低位体系域、湖扩张体系域及高位体系域,通过地震反射特征分析对各体系域进行了横向追踪,并讨论了不同体系域砂体的展布特征及其控制因素和对油气成藏的影响。更多还原

【Abstract】 In contrast with the more mature sequence stratigaphy on lacustrine deposits during active tectonism,it is still in an explorative period nowadays to research stratigraphic sequences of peneplain deposits during lacustrine shrinking.Lower Member of Neogene Minghuazhen Formation is a set of lacustrine shrinking deposits in the area of Yellow River mouth,and can be taken as a case of the sequence stratigaphy.Palaeoclimate changes to control sequence development may serve as leads,and the relationship between palaeoclimate changes and lacustrine level changes is analyzed.Furthermore,variations of several parameters caused by palaeoclimate changes,such as spore-pollen assemblage,algal abundance and differentiation,clay mineral composition and content,and gamma-ray logging response,are studied,which can be used as evidences to divide sequences.Based on the lacustrine level changes and by analyzing the base level and A/S changes,Lower Member of Minghuazhen Formation can be divided into a LST,a TST and a HST.These system tracts were laterally traced by analyzing the seismic signatures,and sandbody distribution,its controls and its impacts on hydrocarbon accumulation have been discussed for each system tract.更多还原