焉耆盆地博湖坳陷三工河组下段地震相—沉积相分析

摘要

In order to study the favorable distribution area of lithologic traps in Bohu Depression of Yanqi Basin,based on seismic sequence division,the amplitude,frequency,continuity,internal structure and external form of seismic reflection wave were applied to analyze the seismic facies in the study area,and the seismic facies of the target zone can be divided into six types.The seismic facies is transformed into sedimentary facies by means of well-seismic combination.The result shows that six types of sedimentary facies are distinguished in the lower segment of Sangonghe Formation of Bohu Depression,including alluvial fan,braided river delta plain,delta front,shore-shallow lacustrine,turbidite fan and semi-deep lake facies.Meanwhile,there developed five types of larger sedimentary bodies,which corresponds to the three provinces in the northwest,northeast and south of the study area.It is considered that lithologic traps are less developed in the lower segment of Sangonghe Formation,only formed in the locally developed mouth bar,shore-shallow lacustrine beach bar and turbidite fan.%为了探究焉耆盆地博湖坳陷岩性圈闭发育的有利区带,在地震层序划分的基础上,利用地震波振幅、频率、连续性、内部结构以及外部形态等特征,在研究区目的层划分出6种地震相类型。通过井-震结合,将地震相转化为与之相对应的沉积相。结果表明：三工河组下段主要发育冲积扇、辫状河三角洲平原、三角洲前缘、滨浅湖、浊积扇、半深湖等6种沉积相（亚相）类型;同时该区发育5个规模较大的沉积体,大体上对应着北西、北东及南部3个物源区。综合分析认为,三工河组下段整体上岩性圈闭发育条件较差,局部发育的河口砂坝、滨浅湖滩坝、浊积扇等可以形成岩性圈闭。