Sedimentary characteristics and microfacies model of No.4-7 delta front sand-body,the upper of the 2^nd member of Shahejie Formation,southern Pucheng oilfield

The reservoir sedimentary characteristics of the No.4-7 sand sets in the upper of the 2^nd member of the Shahejie Formation in southern Pucheng oilfield were fully studied in terms of regional geology,seismic,well log as well as core analysis.The result indicates that the 4-7 sand sets belong to a kind of delta front deposition developed in a little occlusive non-marine fault-trough lake basin.The reservoir is of low compositional and textural maturity,and can be divided into 7 types of micro-facies.Meanwhile,the vertical sequence and the evolution models of the delta front sand-bodies in this area are established. Furthermore,the lateral distributing regularities of the micro-facies are summarized.