Reservoir Prediction Of Glutenite Body Combined With Well And Seismic Data In The Fourth Member Of Shahejie Formation In Yanjia Oilfield,Dongying Depression

Gravity flow glutenite deposits are developed in the upper sub-member of the fourth member of the Shahejie Formation of Yanjia Oilfield in Dongying Depression.Accurately characterizing the distribution characteristics of the glutenite body at different stages is the basis for formulating development plans and the key to describing the glutenite reservoirs.However,due to the complex internal structure of the glutenite body and the strong reservoir heterogeneity,it is difficult to divide and compare the sedimentary stages finely.At the same time,due to the large well spacing and low frequency of seismic data in the study area,the difficulty of accurately characterizing the distribution characteristics of the glutenite body is increased.Relying on traditional experience and subjective knowledge to predict the inter-well glutenite body is poor.As a result,the regularity of the plane and spatial distribution of the glutenite body is unclear,and it is difficult to meet the needs of fine potential excavation in the development stage.In response to the above problems,this thesis established a fine isochronous stratigraphic framework based on the genesis model of sedimentary cycles,interpretation and tracking of seismic horizons,and multi-dimensional interactive three-dimensional closure.Through the method of intelligent attribute fusion based on support vector machine,Bayesian sparse pulse inversion,and phased coordinated sequential instruction simulation,the two-dimensional distribution characteristics of glutenite body are characterized,and a three-dimensional spatial distribution model of glutenite body is established.Finally,through the analysis of the sedimentary background and sedimentary facies symbols in the study area,the types of sedimentary environment in the study area are recognized,a template for interpretation of sedimentary subfacies is established,and the distribution and evolution of sedimentary subfacies are explained.The results show that:(1)The upper member of the fourth member of the Shahejie Formation in the Yanjia Oilfield can be divided into eight sand groups.Each sand group corresponds to the development of a relatively large glutenite body.The sedimentary model has the characteristics of vertical multiple sedimentation ordered combination,positive sequence superposition of multiple sedimentary cycles,lateral sedimentation compensation migration,and stable mudstone development between cycles.(2)The intelligent attribute fusion method significantly improves the correlation between seismic attributes and the thickness of the glutenite body,thus improving the prediction accuracy of the glutenite body.(3)The glutenite body is always distributed along the edge of the lake basin next to the foothills,and the edges of multiple sets of glutenite body are superimposed,and distributed in a strip-like pattern along the boundary fault.(4)The study area has the characteristics of typical underwater,nearshore,gravity flow deposition,and its sedimentary facies is identified as nearshore underwater fan,which can be divided into three subfacies:fan root,fan middle and fan margin.(5)During the sedimentary period of the upper sub-member of the fourth member of the Shahejie Formation,there were 8 stages of near-shore underwater fan deposition,with the fan body spreading from north to south,and the ratio of glutenite thickness to formation thickness decreased.From the 8^th sand group to the 1^st sand group,as the lake basin and the shoreline receded,the source of supply decreased,and the glutenite fan body generally showed a receding pattern,with a corresponding feature of"ditch-fan".In the early sedimentary stage,the fan bodies were superimposed,and in the later sedimentary stage,the fan bodies tended to be separated.