High order optimization Fourier finite difference operator migration method
Zhu Sui-wei1,2, Zhang Jin-hai1, Yao Zhen-xing1
1. Institute of Geology and Geophysics, China Academy of Sciences, Beijing City, 100029, China;
2. Geophysical Technique Research Centre, BGP Inc.of CNPC, Zhuozhou City, Hebei Province, 072750, Chian
Abstract:It is known that both adding more high order terms and optimizing coefficients can raise the precision of Fourier finite difference (FFD) operator. Adding more high order terms means increasing computational complexity while under the circumstance of not increasing the computational complexity optimizing coefficients can raise the precision of the operator. In this paper the multi-parameter global optimization coefficient method was used to optimize the revised terms in Fourier finite difference (FFD) operator,the propose of the method is to try best to raise the phase precision of the operator while not to increase the equation's order so that the high order equation approximation effect can be reached by using lower order equation,the computational complexity was greatly decreased and the precision of the Fourier finite difference (FFD) operator was largely raised. Different from other methods,this method considers the affects from multi-parameters,such as frequency,continuation step size and so on. The theoretic error analysis and impulse response testing show that the spreading angle of the second order optimization Fourier finite difference (FFD) operator can reach almost 90 degree. 2-demensional SEG/EAEG dome modeling test demonstrates that imaging precision of the method for steep dip and subsalt structures is much higher than non-optimized Fourier finite difference (FFD) method.