Seismic Sedimentary Analysis And Reservoir Prediction Of Dongying Formation On The East Slope Of Chengdao

The Chengdao area is located at the confluence of the Jiyang Depression and the Bozhong Depression,which is a large-scale buried-hill plated structural belt surrounded by oil-bearing depressions.It mainly includes the Chengbei fault zone,the buried-hill deposit zone,the slope zone and the Chengdao-Zhuanghai combination part.In addition,the sand body distribution of sublacustrine fan in east slope of the Chengdao Island is closely related to the valleys,structural slope break zone and fault activities.The seismic data of the Dongying Formation has poor quality and low resolution,and its reservoir description is very difficult to fulfill;Turbidity is the dominant sedimentary type.Such reservoirs have features of blanks,medium-weak complex waves etc.The reflection regularity of the sand body in seismic section is not clear,which is difficult to identify and track and it results in the diversity of lithologic interpretation.The conventional processing methods cannot meet the research requirements of such reservoirs and it is also difficult to perform the fine reservoir description.It has high requirements on the resolution of seismic dataand Seismic sedimentology,which is developed on the basis of seismic stratigraphy,sequence stratigraphy,sedimentology,and geophysics can satisfy this demand and is further enhanced by comprehensive analysis which combines well data and seismic data,we can analyze the distribution law of reservoirs,sedimentary facies,oil and gas,which can help us predict favorable drilling targets.Combining the results of previous studies and comprehensive using of core,well log,logging and seismic data,we established the isochronal stratigraphic framework of the Dongying Formation of Chengdao east slope.Then the Dongying Formation of Chengdao east slope was divided into a second-order sequence and four three-level sequences,and five sequence interfaces was identified.We think that the mainly types of sedimentary facies in this area are flooded lake bottom fan,slumped lake bottom fan and fan delta.Based on the above understanding,we applied seismological techniques to perform the seismic sedimentology study of Dongying Formation.Weused 90° phase transformation,frequency interpretation,seismic facies analysis,attribute analysis and stratigraphic slicing techniques to carry out sedimentary evolution study.We performed seismic inversion under the constraint of sequence,to have further implement of sand body's development.During the inversion process,we made full use of seismic and well logging data to predict the distribution of sand body in Dongying Formation.Based on the seismic inversion results and the study of seismic sedimentology in Dongying Formation,two favorable targets were optimized.