Seismic facies and sedimentary facies of the lower segment of Sangonghe Formation in Bohu Depression,Yanqi Basin

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.