Eda Media Parameters Inversion

The influence of Horizontal Transverse Isotropy (HTI) always exists in fractured reservoir. It exists directional velocity difference, directional amplitude difference, reflected wave shape and phase difference. In this paper, I try to use the directional amplitude difference and directional velocity difference to carry out the parameter inversion of the fracture.At first, a specific analysis is done to Hudson theory and Thmosen theory and the description of fracture given by Hudson, Thmosen and Tsvankin . We give an analysis to the azimuthal NMO velocity and the change of azimuthal amplitude given by Tsvankin and Ruger respectively. On this basis, we did the physical model experiment and numerical simulation. After these, we use the above seismic attributes to do the parameter inversion.In fractural physical model experiment, after the analysis of the reflected P wave varying with observed azimuth at a certain offset in the simulated fractured media, we get the traveltime difference varying with observed azimuth. Also we can infer the azimuthal NMO velocity difference in fractured media. We can see the P wave amplitude and traveltime difference with the azimuth and incidence angle in numerical simulation. These results give us the evidence to use the amplitude and NMO velocity difference for parameter inversion in fractured media.In the inversion of parameter φ_sym , we deduce the formula for parameter φ_sym inversion from PP wave reflection coefficient given by Ruger, then using the method of SVD to give the result of φ_sym. Numerical simulation and field P wave data were done for φ_sym inversion. In fracture density e inversion, we calculate the traveltime from different azimuth and incidence, and then get the NMO velocity at different azimuth. We use the above data to get the anisotropic parameter γ^ν, finally we estimate the fracture density e.Using the AVOA character of P wave for parameter inversion of the fracture, wide azimuth data is required, and the CMP gathers for inversion should be of high S/N, fidelity and resolution. All of these give high requirement to the data acquisition and processing.