Acoustic Waveform Inversion In Anisotropic Media

Full waveform inversion use the information of full wave field effectively,including the information of phase and amplitude,using the method of iterative updating model parameters to minimize the difference between synthetic seismic data and real data.It can provide an accurate model parameters,providing reliable velocity data for migration imaging and lithology recognition.In this thesis,we provide the basic inversion theory of acoustic waveform inversion in anisotropic media.First,we derivate the wave equation of acoustic in anisotropic media for modeling.Preparing for acoustic waveform inversion in anisotropic media.Second,introduce the calculation of gradient and the inversion process for acoustic waveform inversion in anisotropic media.Third,the results of model test prove the accuracy and validity of the method.Full waveform inversion provide the accuracy velocity data,but at present,the research is only limited to isotropic media,For the data of anisotropic media,the result of acoustic waveform inversion in isotropic media is error.To deal with this problem,we have researched on these aspects as follows: First,we start from the dispersion relation of elastic wave in VTI media,setting the shear wave velocity along the symmetry axis to be zero,then we acquire the acoustic wave equation in VTI media.Through the method of rotating coordinate system acquire the acoustic wave equation in TTI media.The acoustic wave equation in anisotropic media prepare for acoustic waveform inversion in anisotropic media.Second,we introduce the formula of gradient for acoustic waveform inversion in anisotropic media,and introduce the inversion process of acoustic waveform inversion in anisotropic media explicitily.Third,the model test proved the method of acoustic waveform inversion in anisotropic media is accuracy and validity.We only inverse the velocity in anisotropic,not including the parameter of anisotropic.