Globally optimized fourier finite-difference migration method.

Fehler, M. ; Huang, L.

Technical Information Center Oak Ridge Tennessee

关键词: Fourier analysis;    Finite difference method;    Coefficients;    Optimization;   

RP-ID  :  DE2000763348

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

To image complex structures with strong lateral velocity variations and steep dips, we use a rational approximation of the square-root operator in the one-way wave equation to develop a globally optimized Fourier finite-difference method. The two coefficients in the rational approximation are obtained by an optimization scheme that maximizes the maximum dip angle of the Fourier finite-difference method for a given model. Our optimized method uses the same coefficients throughout a model in contrast to Ristow-Ruhl's locally optimized Fourier finite difference scheme which uses coefficients varying with lateral velocity contrast. The table of coefficients could be huge for a highly accurate optimized scheme. The computational cost of our optimized method is the same as other Fourier finite difference methods. Our optimized method is accurate for dips with angles of approximately 15 deg.-200 larger than that of Ristow-Ruhl's unoptimized Fourier finite-difference method, while Ristow-Ruhl's optimized scheme can handle approximately 16 deg. larger dip angles than their unoptimized scheme.