Study On Prediction Of Tight Sandstone Reservoir

China is rich in tight sandstone oil and gas reservoir.In geophysical prediction of tight sandstone oil and gas reservoir,there is still a lack of complete technical means.In China’s unconventional oil and gas resources,tight oil and gas resources account for a large proportion.In the Songliao Basin,Lishu area is located in the southeast uplift area.In this area,tight sandstone reservoir has low porosity and permeability.There are some problems,such as low trial production yield and unclear distribution of "Sweet-spot" area.In this thesis,the sensitive parameters of lithology,porosity and fluid are obtained through petrophysical intersection analysis based on the optimization processing of prestack gathers and logging data processing,then tight sandstone reservoir prediction is realized based on the prestack elastic parameters of prestack inversion.Establish the quantitative relationship between sandstone content and density,density * shear modulus and buried depth,quantitatively characterize the change of sandstone recognition ability with buried depth of different parameters,fit the formula,and substitute the inversion results to realize lithology prediction;establish the quantitative relationship between density and porosity and fit the formula,and substitute the density parameter to realize porosity prediction;establish the quantitative relationship between P-wave impedance and Vp/Vs and combine the coordinate rotation technology to realize fluid prediction;the elastic "Brittleness index" formula is used to substitute the inversion results into the prediction of brittleness;based on Rp data and Rρ data,the crack prediction is realized by ant body tracking technology.Based on the prediction results of lithology,porosity,brittleness,fluid and the development of cracks in the study area,the location of "Sweet-spot" of tight sandstone reservoir is found out.Nearshore underwater fan sedimentary sand bodies are developed in both K1Y1 member and T41 member.Generally,the "Sweet-spot" characteristics of T41 member are better than K1Y1 member.