基于模型数据的噪声能量对叠加、偏移结果的影响分析

地震资料中不可避免地存有噪声,噪信比(噪声能量与信号能量之比)可能对地震成像造成致命的影响。根据自行设计模型,采用正演方法生成138炮记录,在这些单炮上分别加上不同能量的随机噪声和相干噪声,并应用模型速度进行NMO校正、叠加或进行叠前深度偏移;在这些工作的基础上,进行不同能量的随机噪声对叠加结果的影响分析,同能量随机噪声和相干噪声对叠加结果的影响分析,同随机噪声能量对叠加和偏移影响分析及同能量随机噪声、相干噪声对叠前深度偏移结果分析。这种分析建立在信噪比已知、速度已知、叠加及偏移算法已知的背景下,因而具有较高的准确度。最后,根据这些实验分析,得出各种不同噪信比的噪声对叠加、叠前偏移的影响进行给出定量结论,以期对地震资料处理中去噪技术的应用提供帮助。

The impact analysis of noise energy to the stack and migration based on the model Data

Noises inevitably exist in seismic data. How large of the ratio of the energy of noises and signals (s/n ratio) may result fatal influence on the seismic imaging? This article is answering this question in the following way: We first generate 138 records by the forward modeling method of our self-designed model. Then we add random noises and coherent noises, and run the NMO correction, the stacking or the pre-stacking depth migration by applying model velocity. On the basis of these works, we then analyze the respective influences of the superposition results of random noises of different energy, the superposition results of random noises and coherent noises of the same energy, the superposition and migration results of random noises of the same energy, and the depth migration results of pre-stacking. We build the analysis on the models that the s/n ratio, speed, and the algorithms of superposition and migration are all known. Therefore, the result has a high accuracy. Finally, we state the conclusion of the influence of the superposition and pre-stacking migration of noises of different energy according to the analysis of experiment results, in order to help the application of the denoising technology in seismic data processing.