The exploration focus in the Dongying Formation of Chengdao area

the Bohai Bay Basin is stratigraphic-lithologic reservoirs

to which the key is a correct understanding of deposition characteristics of reservoir sandbody.A comprehensive analysis of core

drilling/logging

and seismic data of the area

confirms the existence of sedimentary systems such as deeper lake-turbidite fan

fan delta-slump turbidite fan

braided delta

low-sinuosity stream-flood plain

and etc

and provides insights into the composition and features of these sedimentary facies.The results indicate that palaeogeomorphic characteristics before the deposition of the Dongying Formation show a strong controlling effect upon the deposition of the lower Dongying Formation.Based on sedimentary facies analysis within the sequence stratigraphic framework

the paper discusses the spatial distribution of these sedimentary facies and the petroleum geologic significances of the study on sedimentary features in such aspects as the types and distribution of reservoir sandbody

favorable strata

characteristics of spatial distribution

and so on.