Reservoir-I in the lower part of the third member of the Shahejie Formation is attributed to midfan external fan facies zone of nearshore turbidite fan in Zhang-52 block fault

Zhanhua Sag.According to the division of single well base level cycle and the correlation of key horizon on 3-D seismic progile

oil reservoirs exist in the progradation retrogradation bodies extending from south to north based on isochronous principle

the isochrosnous relation of the top and base boundaries of the reservoirs of adjacent wells were made out

so the seguences of sedimentary cycles of each well.Then the nearshore turbidite bodies in the study area were divided into 20 imbricate prograding bodies.In vertical

single well may drill four subbeds.The south edges of the turbidites are near the onlap boundaries of the turbidites and the reservoir grain grade appears positive rhythmic property while that of the north edges shows negative rhythmic property

the central part of the subbeds are massive homogeneous deposits.The physical properties and petroleum bearing property of the subbeds get better from south to north and the best ones are in the central and north parts of the study area.