Zhanhua sag is the sub-tectonic unit of the Jiyang depression in Bohaiwan Basin. In order to find out the regularities of distribution and the characteristics of the reservoir in Upper Es2 of the Zhanhua sag, based on the data of the core,well-logging,seism,thin-section and the physical property in 84 wells, the characteristics of the sedimentary and diagenetic evolution of the reservoir are studied systemically. The reservoir primarily appeared in some microfacies, such as the fan-delta subaqueous distributary channel, mouth bar, beach-bar in the littoral and shallow lake. The reservoir is primarily lithoclastic quartz sandstone and lithic sandstone; the pore is chiefly primary pore;and the porosity and permeability of the reservoir are between 8% and 24%, 1×10-3μm2and 100×10-3μm2 respectively. Applying the theory of the diagenetic facies and cluster methods, the reservoir is classified into three types, which are respectively weak compaction and clay cementation, middle compaction, strong compaction and solution. Based on the analysis of the characteristics of three facies, the distribution ichnography of the diagenetic facies is completed.
