Attribute Extraction Of Multi-wave Joint Elastic Impedance Inversion Based On Lateral Consistent

As an inversion method based on pre-stack partial stack gathers,elastic impedance inversion can not only overcome the sensitivity to noise in AVO inversion,but also save abundant pre-stack information,thus it has become one critical technique for hydrocarbon reservoir detection.However,problems including unstable inversion process,inaccurate inversion results and weak indication of oil and gas will exist in the there-parameter inversion merely using PP-wave data.Hence,with the combination of PP-wave data and PS-wave data,research on attribute extraction method of elastic impedance with the constraint of Kalmanfiltering is carried out in this paper,and then applied to hydrocarbon detection.In order to solve the problem of weak hydrocarbon indication for the inversion parameters,fluid indication factor F? and lithology indication factor E? with high sensitivity is selected through sensitivity comparison analysis.Sensitivity of the fluid factor is close to that of Rusell fluid factor,and can avoid the error caused by the calculation of P and S-wave velocity ratio of dry rocks.For the problems of unstable inversion process and inaccurate inversion results,approximated reflectivity formula of PP-wave and PS-wave based on fluid indication factor F? and lithology indication factor E? is derived first in this paper.Referring to the theory of Connolly elastic impedance,elastic impedance function PP-wave and PS-wave based on F?and E? is then derived and the accuracy of the function is also analyzed.With the full use of PP-wave and PS-wave data,objective parameters are directly extracted for hydrocarbon indication through elastic impedance inversion.Meanwhile,since the lateral consistency of the elastic impedance inversion results is poor,Kalman filter operator is included in this paper for lateral constraint in the process of inversion.Finally,through the test of theoretical model and real data,the proposed attribute extraction methods based on joint PP-and PS-wave inversion of elastic impedance inversion with lateral constraint is proved to be stable,accurate and can indicate the existence of hydrocarbon.The results show that this method perform better than inversion methods with single PP-wave data in the aspect of stabilization and accuracy.Meanwhile,the inversed fluid factor and lithology parameter can well identify the fluid and distinguish the lithology for effective reservoir fluid detection.