| 地震偏移的最优可分近似算法实现 |
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| 引用本文： | 张致付,刘洪,陈景波,李幼铭.地震偏移的最优可分近似算法实现[J].地球物理学报,2005,48(6):1422-1427. |
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| 作者姓名： | 张致付 刘洪 陈景波 李幼铭 |
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| 作者单位： | 中国科学院地质与地球物理研究所，北京100029 |
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| 基金项目： | 中国科学院知识创新工程重大项目（KZCX1-SW-18）、国家自然科学基金（40474047）资助. |
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| 摘 要： | 针对地震偏移算法中单程波算子的特征函数近似，采用最优可分表示法将该特征函数展开为空间变量(g)和水平波数(k)的可分表达式，以此可分近似表达式为基础，运用正反Fourier变换重新构造单程波算子. 为了克服特征函数最优可分近似计算在奇点及其领域产生的数值振荡，引入等价黏性技巧以增强算法的数值计算稳定性，并采用分频最优可分及对空间变量(g)线性插值的方法，不仅提高了计算精度，也节约计算机时. 文中具体研究了单程波算子的脉冲响应和二维叠前深度偏移. 结果表明，在不甚大步长情况下，本文构造的算子具有适应横向强变速的能力，运用Marmousi模型验证了本文方法适合复杂构造的成像.
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| 关 键 词： | 最优可分近似 单程波算子 特征函数 偏移 |
| 文章编号： | 0001-5733（2005）06-1422-06 |
| 收稿时间： | 2004-11-02 |
| 修稿时间： | 2004-11-022005-06-14 |
Implement of optimal separable approximation in seismic migration |
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| ZHANG Zhi-Fu,LIU Hong,CHEN Jing-Bo,LI You-Ming.Implement of optimal separable approximation in seismic migration[J].Chinese Journal of Geophysics,2005,48(6):1422-1427. |
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| Authors: | ZHANG Zhi-Fu LIU Hong CHEN Jing-Bo LI You-Ming |
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| Institution: | Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China |
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| Abstract: | An optimal separable approximation(OSA) is applied to the characteristic function of one-way wave operator in the seismic migration algorithm.The characteristic function is expressed as products of functions in space variable(g) and functions in wave number variable(k).Based on the optimal separable approximation,the mixed domain algorithm with Fourier and inverse Fourier transformation is used to approximate the one-way wave operator.To overcome numerical instability from approximating characteristics function near the singular point,an equivalent sticking skill is adopted to improve algorithmic stability.Moreover,separate frequency computation and linear interpolation for space variables are used to improve precision and save time.The impulse response of one-way wave operator on simples and the complex lateral variable velocity model shows that the optimal separable approximation can apply to lateral velocity variation in the case of small steps.Results on the Marmousi model test show the new method can also be used to image complex structure. |
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| Keywords: | Optimal separable approximation One-way wave operator Characteristic function Migration |
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