Abstract: Through systematic research of core observation,logging interpretation and sedimentary reservoirs of Es4 in western slope of Damintun,it is believed that fan delta sedimentary system is well developed and the front fan delta are mainly of mudstone and silty sandstone.Meantime,in Shen-262 and Shen-273 well areas,it also developed typical lenticular turbidite sand body,formed in fan delta front sub facies forward fan delta sliding collapse.The fan delta front mainly developed fluvial sandstone,fine sand and gravel sandstone lithology,and it is widely developed and has good physical properties in the area.The fan delta mainly developed glutenite,and its deposition is mainly on the continental sedimentation,and Shen-267 well and Shen-357 wells can be seen clearly in the onshore sedimentary characteristics.The color of the mudstone is complex,and the red beds and the carbonaceous mudstone are developed.Sedimentary period can be divided into low system tract and water inlet system,and the low system tract developed fan delta sedimentary system.Two sub phases of fan delta front and frontfan delta were developed in the water inlet system,and there was no fan delta plain sub facies.The types of reservoir sand bodies are relatively single,with fan delta front sand bodies as the main reservoir lithology mainly developed conglomerate and sandstone.The main types of reservoir space are intergranular pore,dissolution pore and micro fracture and dissolution fracture.The pore structure of the reservoir is characterized by low permeability,medium pore and micro fine throat.