Prediction Of Sand Body And Sedimentary Architecture Using Intelligent Seismic Method Of The Second Member Of Xishanyao Formation In The Eastern Niujuanhu Area,Santanghu Oilfield

The West Second member of the eastern Niujuanhu in Santanghu Oilfield belongs to the braided river delta front depositional system.The sediment supply is north-south,the sand-body distribution is contiguous,the heterogeneity is intensive,and the stacked relationship of different sand-bodies is unclear.The traditional single geological method cannot accurately depict the distribution of sand-bodies and their stacked relationships.Therefore,it is necessary to combine seismic and geological data to carry out the distribution of sand-bodies and the related sedimentary architecture in the study area,so as to better guide oilfield development.Based on the available data,this paper establishes a stratigraphic framework and defines their pattern in the study area.On the basis of suppressing strong axial reflection of coal seam,combined with seismic attribute fusion and seismic intelligent inversion to predict the spatial distribution of sand-bodies,and further through collaborative modeling to improve vertical sand-body identification accuracy to complete the single-layer sand-body distribution prediction.Finally,by synthesizes the sedimentary background and sand-body prediction results of the study area,the composition of the target formation and architecture unit is defined,and the multi-stage reservoir and architecture characterization is performed.The results produce 5 conclusions.（1）The second member of Xishanyao Formation in the eastern Niujuanhu area has a simple structure with undeveloped faults and a low dip angle monoclinic structure;the lateral distribution of the four inner monolayers tends to be stable,and the vertical accretion development is nearly isothick.（2）Sand-body prediction techniques combined with well and seismic data is applied to effectively improve the prediction accuracy of thick sand-body in the study area.In contrast,artificial intelligence inversion technology uses multiple wavelet decomposition and reconstruction to suppress coal seam response,combined with logging curves,and the accuracy of sand-body identification is higher than seismic attributes.On this basis,the inversion data body collaboration simulation technology is used to determine the distribution characteristics of single-layer sand-body.（3）There are two provenance sources in the working area,the provenance supply in the south increased and the provenance supply in the north decreased,indicating that the northward migration of the lake basin shrank.There are differences in the development degree of the four single-layer sand-bodies,in which the J₂x₂¹ and J₂x₂² sand-bodies are contiguous without obvious mudstone boundary.The J₂x₂³ sand-body is underdeveloped in the central and eastern part of the study area.The J₂x₂⁴ sand-body has the smallest distribution range and is mainly developed in the north.（4）The West Second member of the eastern Niujuanhu area is a braided delta front deposit,which mainly develops underwater distributary channel and mouth bar.By summarizing 5 kinds of boundary identification marks of mouth bar,the identification of single-layer mouth bar is completed.The single mouth bar developed in the West Second member of the Eastern Section is mostly in the shape of a dot,distributed in a contiguous plane or separated by unstable dam edges and mudstones,and its thickness,width and length have a good correlation.（5）In the West Second member of the eastern Niujuanhu,there are five types of single architecture unit plane combination,including bar main body-bar main body,bar main body-bar side edge-bar main body,mouth bar-mud between bars,channel full cut mouth bar and channel half cut mouth bar.