高阶优化傅里叶有限差分算子偏移  

High order optimization Fourier finite difference operator migration method

作　　者：朱遂伟[1,2] 张金海[1] 姚振兴[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029 [2]东方地球物理公司物探技术研究中心,河北涿州072751

出　　处：《石油地球物理勘探》2009年第6期680-684,共5页Oil Geophysical Prospecting

基　　金：中国科学院知识创新工程项目(KZCX2-YW-101)

摘　　要：利用增加高阶项和优化系数的方法都能提高傅里叶有限差分(FFD)算子的精度。但增加高阶项意味着计算量增加,而利用优化系数的方法能够在不增加计算量的前提下提高算子的精度。本文利用多参量全局优化系数的方法对傅里叶有限差分算子中的高阶有限差分校正项进行了优化,旨在不提高方程阶次的情况下尽量提高算子的相位精度,即用较低阶的方程达到高阶方程的逼近效果,既大大减少了高阶项产生的计算量,又明显提高了傅里叶有限差分算子的精度。此法不同于其他方法之处在于还考虑了频率和延拓步长等多参量的影响。经理论误差分析和脉冲响应测试,均表明二阶优化傅里叶有限差分算子的精确传播角度可以接近90°。通过二维SEG/EAGE盐丘模型实验,表明此法的陡倾角和盐下构造的成像精度明显高于未优化的傅里叶有限差分法。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.

关 键 词：傅里叶有限差分 多参量 全局优化 高阶分裂 

分 类 号：P456.7[天文地球—大气科学及气象学] P631.443