【摘要】 以地震波单程波传播方程为基础,利用有理式展开方法,推导出一种新的高精度波场传播算子。该算子波场延拓满足分裂步框架,采用快速傅里叶变换(FFT)进行计算。频散曲线分析以及数值试验的对比研究表明:本文方法的波场成像能力明显优于裂步傅里叶法(SSF),可以达到与傅里叶有限差分法(FFD)类似的波场成像效果。计算效率方面,其波场延拓只需三次FFT计算和一次插值,仅比SSF多了一次FFT和插值,但比FFD(计算量相当于五次FFT)少了两次FFT。这种算子不仅精度高,稳定性好,而且计算效率高,具有重要的理论意义和实际应用价值。更多还原

【Abstract】 Based on one-way wave equation,we propose a new wave-field extrapolation operator of high-accuracy using rational expansion method.This operator uses split-step framework and Fast Fourier Transforms(FFT) in wave-field continuation.Analysis results of dispersion curves and numerical experiments show that the imaging capability of this operator is significantly better than split-step Fourier method(SSF).Its imaging capability is nearly as good as Fourier Finite Difference method(FFD).In the aspect of computing efficiency,the operator only needs 3 FFTs and one interpolation,which is one more FFT and interpolation than conventional SSF(needs 2 FFTs) in computation,but two FFTs less than FFD(equivalent to 5 FFTs).It is not only highly accurate,unconditionally stable,but also highly efficient in migration imaging.This method is of important theoretical and practical significance.更多还原