Abstract：There are tow kinds of wave equation numeric modeling methods: finite-difference approach and approach in frequency-wavenumber domain,among which the computation precision of finite-difference method depends on the approximate degree of wavefield extrapolation operator,discrete grid interval and order of finite-difference equation,it is adapted for any lateral variations of velocity,but the dispersion and background noise are easily presented in large dip. The algorithm in frequency-wavenumber domain is characterized by simple,high-precision,small noise and adaptive to any dips of strata,but inadequate for any lateral variations of wavefields.Combining the advantages of frequency-wavenumber domain with Finite-Difference approach,the paper used Fourier Finite-Difference (FFD) approach to finish the numeric simulation of seismic records of model by using high-precision continuation operator and in multi-domain.The extrapolation operator of wavefield is composed of phase-shift item,refraction item (time-shift item) and finite-difference compensation item.The theoretical and error analyses are carried out for FFD method,and one-way acoustic wave equation is used to do numeric simulation test for layered model and SEG/EAGE salt model respectively.The correlation of numeric tests showed the FFD method is adaptive for severe lateral change of velocity field and characteristics of high precision,no-dispersion and weak background noise,and the reflection feature is distinguishable in simulated results,which can carry out accurate numeric seismic simulation of complex geologic structure.
