基于地震物理模拟数据的频率域声波方程波形反演研究

Seismic full waveform inversion seeks to make use of the full information based on full wave-field modeling to extract quantitative information from seismograms. We derived the forward wave equation algorithm in frequency domain, and then used the classical staggered grid in the finite-difference modeling method. The PML absorbing boundary is accomplished to compute the numerical solution of the acoustic wave equation in frequency domain. The Matrix formalism for the iterative inverse methods is derived which include gradient and Gauss-Newton methods to speed up calculation and to avoid convergence to local minimum value. After massive amount of frequencies tests, the appropriate bandwidth are extracted, and the velocity field calculated at low frequency is used as the input of the high frequency. After the iteration, the accurate velocity field is inverted. Discrete grid and distributed parallel calculation methods are used to improve calculation efficiency. Acoustic wave equation full waveform inversion in mathematical and physical models is conducted in order to improve the accuracy of complex geological structural imaging and heterogeneity prediction.