Study On The Characteristics Of Sandbody Reservoir Of The Es3～z Member In The West Of Niuzhuang Sub-sag Of Dongying Sag

The intermediate section in member 3 of Shahejie Formation in Niuzhuang sub-sag Shengli Oil Field is the most important part for oil exploitation,and the type of oil storage of this part is lithologic reservoirs.In this thesis,the strata of this area are divided into fourth-order sequence,further fifth-order sequence on the base of third-order sequence, according to high resolution sequence stratigraphy,sedimentology and geophysical exploration etc.The Middle Es3,third-order sequence has been subdivided into six fourth-order sequences.In virtue of fifth-order sequence divided by earthquake profile,the precision of sequence strata division and correlation is improved and the characteristics of different sandbody reservoirs can be correlated.Combining with high resolution sequence framework,the turbidite sedimentary microfacies of delta costal margin and prodelta are divided in Niuzhuang sub-sag.On the basis of fining microsequence division and correlation,the sedimentary microfacies horizontal distribution is analyzed through logging curve shape,distribution and assemblage of different wells,united with channel sand distribution.Using statistic measures,the lithology,physical characteristics,electrical characteristics and oiliness of reservoirs and relationships among them are studied particularly.The results indicate that gravel sandstone,fine sandstone,silt fine sandstone and mud siltstone in the Middle Es3 reservoirs contain good oiliness.It is consider that calcite cement and mud content play a dominate role in the origin of subtle oils.The reservoirs physical parameters are higher, the oiliness is better.Lower limit porosity of oil shown samples is 7%,oil immersed and upwards samples is 12.5%,permeability is 0.02×10^-3μm².The better oil-gas potential and the higher saturation of oil reservoir are,the higher negative anomaly of SP curve and the higher RT would be.From dry layer,oil-water layer to oil layer,the higher negative anomaly value of SP varies from 10mV,18mV,to 38mV increases gradually.From oil-water layer to oil layer,RT value varies from 3Ω-6Ω.Determinate porosity,permeability and saturation and the foundation of diagnostic standard of oil layer,gas layer,water layer,dry layer will be helpful for the classification and exploration of oil in Niuzhuang sub-sag,according to study of"four characters" in this area.