Seismic Inversion Of Daniudi Dolomite Reservoir In Ordos

With the development of seismic exploration,post-stack seismic inversion has gradually been unable to meet the actual production requirements due to the singularity of inversion results.Different from wave impedance parameters obtained by post-stack inversion,pre-stack seismic inversion can calculate lithologic parameters such as P-wave,S-wave and density,from which a series of other parameters can be obtained.Joint interpretation of multiple parameters effectively improves the accuracy of exploration.Therefore,pre-stack inversion plays an increasingly important role in the field of oil and gas exploration.The complexity of accurate Zoeppritz equation limits its application in pre-stack inversion.Aki-Richards approximation formula is widely used because of its simplicity and accuracy.In the use of this approximation formula,three parameters mentioned above are first obtained,which are then exploited to calculate other rock parameters more sensitive to oil and gas,such as Poisson's ratio and Lame's coefficient.However,due to the uncertainty of inversion results and the influence of noise in seismic data,the accuracy of lithology parameters obtained by Aki-Richards approximation formula will be reduced,and the accuracy of Poisson's ratio parameters are suffered.Therefore,this paper presents an inversion method based on Aki-Richards formula to directly calculate Poisson's ratio.The advantage of this method is that it omits the process of calculating Poisson's ratio by using three lithologic parameters mentioned above,which helps to reduce the influence of computer truncation error on inversion results.In addition,this method still inherits the simplicity of Aki-Richards approximation formula.Subsequently,two-dimensional theoretical model verifies the feasibility of this method.Finally,the method is applied to the actual work area and good inversion results are obtained.