We derive formulae of correction for multi-wave geometric spreading and absorption in layered viscoelastic media, this provides the theoretical foundation for true amplitude compensation of field data and for our sens...We derive formulae of correction for multi-wave geometric spreading and absorption in layered viscoelastic media, this provides the theoretical foundation for true amplitude compensation of field data and for our sensitivity analysis. The imaging matrix at a plane reflector between viscoelastic media can be determined in the frequency domain using linearized reflection coefficients through Born approximation. We quantitatively analyze the sensitivity by studying eigenvalues and eigenvectors of the imaging matrix. The results show that two linear combinations of petrophysical parameters can be determined from the multi-wave AVO inversion in the case of amplitude compensation. Multi-wave AVO contains the information of attenuation in the media. However, the sensitivity of multi-wave AVO inversion to attenuation is small.展开更多
Considering Zoeppritz equations, reflections of PP and PS are only the function of ratios of density and velocity. So the inversion results will be the same if the ratios are the same but values of density, velocities...Considering Zoeppritz equations, reflections of PP and PS are only the function of ratios of density and velocity. So the inversion results will be the same if the ratios are the same but values of density, velocities of P- wave and S-wave are different without strict constraint. This paper makes efforts to explore nonlinear simultaneous PP and PS inversion with expectation to reduce the ambiguity of AVO analysis by utilizing the redundancy of multi-component AVO measurements. Accurate estimation of ratio parameters depends on independence of input data. There are only two independent AVO attributes for PP reflectivity （i.e. intercept and gradient） and two for PS reflectivity （i.e. pseudo-intercept and pseudo-gradient or extreme amplitude）, respectively. For individual PP and PS inversion, the values of least-squares objective function do not converge around a large neighborhood of chosen true model parameters. Fortunately for joint PP and PS inversion the values of the least-squares objective function show closed contours with single minima. Finally the power function fitting is used to provide a higher precision AVO attributes than traditional polynomial fitting. By using the four independent fitting attributes （two independent attributes for PP and PS respectively）, the inversion of four ratio parameters （velocities and densities） would be estimated with less errors than that in traditional method.展开更多
基金The study is supported by National Project 863 (No. 820-05-02-03).
文摘We derive formulae of correction for multi-wave geometric spreading and absorption in layered viscoelastic media, this provides the theoretical foundation for true amplitude compensation of field data and for our sensitivity analysis. The imaging matrix at a plane reflector between viscoelastic media can be determined in the frequency domain using linearized reflection coefficients through Born approximation. We quantitatively analyze the sensitivity by studying eigenvalues and eigenvectors of the imaging matrix. The results show that two linear combinations of petrophysical parameters can be determined from the multi-wave AVO inversion in the case of amplitude compensation. Multi-wave AVO contains the information of attenuation in the media. However, the sensitivity of multi-wave AVO inversion to attenuation is small.
基金funded by National 973 Basic Research Developments Program of China (No.2005CB422104)863 National High Technique Research Development Project of China (No.2007AA060505)National Natural Science Foundation of China (No.40839901)
文摘Considering Zoeppritz equations, reflections of PP and PS are only the function of ratios of density and velocity. So the inversion results will be the same if the ratios are the same but values of density, velocities of P- wave and S-wave are different without strict constraint. This paper makes efforts to explore nonlinear simultaneous PP and PS inversion with expectation to reduce the ambiguity of AVO analysis by utilizing the redundancy of multi-component AVO measurements. Accurate estimation of ratio parameters depends on independence of input data. There are only two independent AVO attributes for PP reflectivity （i.e. intercept and gradient） and two for PS reflectivity （i.e. pseudo-intercept and pseudo-gradient or extreme amplitude）, respectively. For individual PP and PS inversion, the values of least-squares objective function do not converge around a large neighborhood of chosen true model parameters. Fortunately for joint PP and PS inversion the values of the least-squares objective function show closed contours with single minima. Finally the power function fitting is used to provide a higher precision AVO attributes than traditional polynomial fitting. By using the four independent fitting attributes （two independent attributes for PP and PS respectively）, the inversion of four ratio parameters （velocities and densities） would be estimated with less errors than that in traditional method.
