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利用初至旅行时进行克希霍夫叠前偏移,在复杂构造地区,其成像很差。为了避免这一问题,我提出了一种计算旅行时的新方法。它计算的是最大能量波至的旅行时,而不是初至旅行时。这种方法估算的是在地震频带中有效的旅行时,而不是通常的高频近似。我对赫姆霍基方程进行求解,来估算几个频率的波场,用它来代替求解程函方程得到旅行时。然后,为了计算旅行时、振幅和相位,我对波场进行了参数拟合。将这些参数用于克希霍夫成像算法而得到的图像,在质量上可与由全波场、有限差分、炮剖面偏移得到的图像相比。
Using the Kirchhoff prestack migration during first arrivals, imaging is poor in complex tectonic settings. To avoid this problem, I propose a new way to calculate travel time. It calculates the maximum energy wave travels to, not when traveling first arrivals. This method estimates the effective travel in the seismic band, rather than the usual high-frequency approximation. I solved the Helmholtz equation to estimate wave fields at several frequencies and used it instead of solving the equation of equation to get the travel time. Then, in order to calculate the travel, amplitude and phase, I parameterized the wavefield. Images obtained using these parameters with Kirchhoff imaging algorithms are qualitatively comparable to images obtained from full-wavefield, finite difference, and gun profile offset.