复杂介质地震波场模拟的单程波方法

One-way wave method for seismic wave field simulation for complex medium

单程波方法是常用的地震正演模拟方法之一。与双程波方法相比,单程波方法的计算量成倍减少,且能保持较高的精度。但由于单程波方法不能获得准确的入射角信息,因而多采用垂直入射的反射系数,使得模拟波场的振幅特征不是实际地层的真实反映。为此,提出了结合频率-波数域反射系数近似公式和相移加插值的改进单程波方法。分别采用双程波虚谱法、常规单程波方法和改进单程波方法,基于Marmousi模型进行了数值模拟,对比模拟结果发现,改进的单程波方法可以准确地模拟振幅随入射角的变化,且具备与双程波方法相同的精度。

The one-way wave method is commonly used for simulating seismic wave,compares with the two-way wave simulation method, the computation of one-way method becomes time of reduction,also maintains higher precision,but the one-way wave method is unable to obtain the accurate incidence angle information,thus the normal incidence reflectivity is used,but the amplitude characteristics of simulated wave field is not the real reflection of actual formations. Therefore,we proposed an improved one-way wave method by combining reflectivity approximate formula in frequency-wave number domain and phase-shift plus interpolation method.Two-way wave pseudo spectral method,conventional one-way wave method and the improved one-way wave method were separately adopted to simulate single shot recorder based on Marmousi model.Comparison on simulated results show that the improved one-way wave method can accurately simulate the changes of amplitude via incident angle and has the same precision with two-way wave method.