The Application Of AVO Fluid Inversion Technology

With the study on the exploration and development of complex terrain, the study in this paper focuses on reservoir characteristic analysis, petrophysics, AVO inversion method and wave impedance inversion. Based on the actual geologic aspects, the study provides a reservoir prediction of the objective area mainly through the pre-stack data processing method, and repartition the important areas for future research. The AVO attribute parameters obtained through the inversion in this paper reveal the variation of the properties of the rock and fluid.Firstly, the reservoir characteristic analysis is based on the petrophysic theory, which enhances the standardization of the well log curves and gives out an evaluation of the sensitivity of the reservoir physical properties. The models described in this paper includes:Voigt-Reuss-Hill model, Hashin-Shtrikman mode, Kuster-Toksoz model, Biot-Geertsma model and Gassmann equation. Two important method for rock modulus calculation, which are Gassmann equation and direct detection method, are concluded in this paper. We get14fluid identification factors by changing the combination of the physical parameters. The more sensitive factors can be figured out through analysis, which can distinguish the area contain oil or water.Through the AVO inversion, we can abstract the lithology parameter in the pre-stack seismic data. The result of the inversion can be more abundant and reliable for that the seismic information in the pre-stack seimsic data is more complete. This method analysis the relationship between the amplitude and the incidence angle, and abstract the seismic parameters including density, P-wave velosity, S-wave velosity, Poisson’s ratio and so on, and then analyse the lithology.This method usually use Zoeppritz equation and its approximation. The AVO inversion based on Zoeppritz equation boosts the convenient operation, high efficiency and practical value. The features of the simplification and approximation of Zoeppritz equation is clearly described in this paper, which gives a better foundation for the research and application of the AVO technique.The AVO fluid inversion method can be derived from the theory foundation above. Because the conventional AVO inversion method is of great uncertainty in fluid identification, the AVO fluid inversion method can provide a result with higher precision which can improve the seismic interpretation resolution.We interpret the seismic data based on AVO attribute, AVO crossplot analysis and some other basic AVO analysis method. The attributes profile including Poisson’s ratio, intercept, gradient and fluid identification factors can be obtained through the AVO inversion, which can reveal the AVO exception with the help of the characteristic curve analysis.