Reservoir sedimentary facies in upper Es_4 on the east slope of Niuzhuang Sub-sag

Based on core observation,drilling,logging and analysis data,the sedimentary facies and microfacies of upper Es4 reservoir on the east slope of Niuzhuang sub-sag are investigated.It is recognized that there are two major sedimentary facies:sublacustrine fan deposition controlled by the northern source system and delta front slumping turbidite fan controlled by the southern source system.The sedimentation of braided channel microfacies of sublacustrine fan and slumping turbidite fan often serve as reservoirs,with sublacustrine fan as the most important type of sedimentation in this area.Based on the log response of different sedimentary microfacies,the distribution of sedimentary facies is analyzed,and the sedimentary pattern and reservoir distribution are generalized for the study area.