【摘要】 在地震、测井、录井及岩芯沉积特征研究的基础上,采用单因素分析多因素综合作图法,划分了民丰洼陷沙三段中亚段各个时期沉积体系的展布范围并分析了各沉积体系之间的相互关系。从沉积体系类型来看,研究区主要发育三角洲、扇三角洲和近岸水下扇沉积体系。其中三角洲沉积体系是沉积的主体,包括永安镇三角洲和东营三角洲的一个分支,纵向上可以分为6个期次,从早期到晚期自东向西推进,同时两者之间由于物源供应强度的变化发生侧向的迁移,并最终交汇在一起。扇三角洲和近岸水下扇沉积仅在洼陷北部靠近陈家庄凸起的地区发育,且主要发育在沙三段中亚段的早期。在洼陷的沉积体系中发现了三种不同类型的可容空间转换现象,并对其成因模式进行了总结。更多还原

【Abstract】 Minfeng sub-sag lies in the southeast of Jiyang Depression,and has super oil-generative and depositional conditions.At present,the degree of lithologic hydrocarbon reservoir exploration is low,so the exploration potential is great.Delta,fan delta and near shore subaqueous fan depositional systems can be found in this area according to the research of seismic,logs and core.Distribution and interaction of depositional systems has been researched based on the identification and analysis of sedimentary feature in the middle of the third Member of Shahejie Formation,Paleogene System(Es 3)in Minfeng sub-sag,using single factor analysis and multifactor comprehensive mapping method. Delta depositional system is the most important one,which can cover the most part of the sub-sag,including Yong’ anzhen delta and a part of Dongying delta.It mainly contains delta front and fore-delta sub-facies,and the main rocks are in the fine sandstone,siltstone,and dark mudstone,etc.Underwater distributary channel facies visible trough cross bedding,wedge-shaped cross bedding,wavy bedding and washing-filling sedimentary structure.Lithology cycles generally show the upward fining cycles,logging curve shapes are the bell-shaped and box-shaped.In distributary stream mouth bar,the sandstone are sorted well and tabular cross-bedding,wavy bedding and bimodal cross-bedding can be found.Lithology cycles generally show the backward fining cycles,logging curve shapes are the funnel-shaped or dentelated funnel-shaped.In distributary bay,horizontal beddings and lenticular beddings are the most popular sedimentary structure,also,wave-generated ripples,shell deposition and phytoclasts can be found.The slump turbidity sandstone interlining in the thin mudstone can be found in fore-delta sub-facies.There are some typical deformation structure and liquefaction structure in the core and finger-shaped and bayonet-shaped in the log curves.The delta can be divided into 6 units which means 6 depositional phases according to the lithological changes in the single well and the forward characters of events in the seismic profiles.Three of them on the top partly omission in the east of the sub-sag.The fan delta and near shore subaqueous fan only deposited in the north of sub-sag closed to Chenjiazhuang uplift during earlier stage of Es3.Looking at the sedimentary evolution from building several profiles in different location,we can found a typical phenomenal that the forward and backward occurred in the same time sometimes.There are three different types:in the early stage,delta in the south continually forward while the near shore subaqueous fan in the north backward;in the middle stage,one lobe of Yong’anzhen delta’s forward while another backward;in the latter stage,the Yong’anzhen delta forward to the south while the Dongying delta backward to the south.These can be summarized into three kinds of transformation of accommodation space according to the genesis:①the transformation of accommodation space caused by tectonic movement between two different sedimentary systems in different structure layers;②the transformation of accommodation space caused by deposition between two different sedimentary systems in same structure layer;③the transformation of accommodation space caused by deposition between two different parts of a sedimentary system in same structure layer.更多还原