| 基于波场传播方向的波动方程偏移有效去噪方法(英文) |
| |
| 引用本文： | 叶瑞超,贾晓峰.基于波场传播方向的波动方程偏移有效去噪方法(英文)[J].应用地球物理,2012,9(1):33-40. |
| |
| 作者姓名： | 叶瑞超 贾晓峰 |
| |
| 作者单位： | 中国科学技术大学地球和空间科学学院 |
| |
| 基金项目： | supported by the National Natural Science Foundation of China (41004045);Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-EW-QN503) |
| |
| 摘 要： | 本文研究分析了双程波波动方程偏移成像中广泛存在的三种主要噪声,特别是针对过去研究中没能很好解决的存在于高速盐丘悬垂边界附近的射线状噪声,提出了基于优化成像条件的有效去噪方法。射线状噪声主要来自于震源一侧波场的下行透射波分量和接收阵列一侧波场的上行散射波互相关成像。这一部分能量具有较强的互相关性,但并不携带真实的反射面信息。它广泛存在叠前偏移成像中,与信号在强度上同量级。多数情况下偏移成像中的相关噪声由方向性传播的波场能量产生。利用波场梯度得到的波场传播角度,可以分离出噪声对应的波场能量,并在成像条件中减去。采用这一方法可以有效地去除多种噪声,包括直达波噪声、散射波噪声和射线状噪声。该去噪方法不依赖波场外推算子,在需要时可以方便地运用到几乎所有的波动方程偏移中去。并且该去噪方法针对噪声的物理根源,对信号的损害很小。对去噪后的偏移成像结果额外地进行波数域滤波处理,可以进一步提高叠加图像的质量。这一去噪方法在超广角单程波偏移成像中取得良好效果,我们同时期待其在其他双程波波动方程偏移特别是逆时偏移(RTM)中的成功运用。
|
| 关 键 词： | 偏移噪声 波场传播角度 波场梯度 成像条件 波数域滤波 |
An effective denoising strategy for wave equation migration based on propagation angles |
| |
| Rui-Chao Ye,Xiao-Feng Jia.An effective denoising strategy for wave equation migration based on propagation angles[J].Applied Geophysics,2012,9(1):33-40. |
| |
| Authors: | Rui-Chao Ye Xiao-Feng Jia |
| |
| Institution: | 1. School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, China
|
| |
| Abstract: | We present an effective denoising strategy for two-way wave equation migration. Three dominant artifact types are analyzed and eliminated by an optimized imaging condition. We discuss a previously unsolved beam-like artifact, which is probably caused by the cross-correlation of downward transmitting and upward scattering waves from both the source and receiver side of a single seismic shot. This artifact has relatively strong crosscorrelation but carries no useful information from reflectors. The beam-like artifact widely exists in pre-stack imaging and has approximately the same amplitude as useful seismic signals. In most cases, coherent artifacts in the image are caused by directionally propagating energy. Based on propagation angles obtained by wavefield gradients, we identify the artifact energy and subtract its contribution in the imaging condition. By this process most artifacts can be accurately eliminated, including direct wave artifacts, scattering artifacts, and beamlike artifacts. This method is independent of the wavefield propagator and is easy to adapt to almost all current wave equation migration methods if needed. As this method deals with the physical artifact origins, little damage is caused to the seismic signal. Extra k-domain filtering can additionally enhance the stacking result image quality. This method succeeds in the super-wide-angle one-way migration and we can expect its success in other two-way wave equation migrations and especially in reverse time migration. |
| |
| Keywords: | Migration artifact propagation angles wavefield gradient imaging condition k-domain fi lter |
| 本文献已被 CNKI SpringerLink 等数据库收录！ |
|
