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在偏移速度分析领域,共成像点道集对偏移速度分析(MVA)而言是非常重要的.目前,用于偏移速度分析的共成像点道集主要有偏移距域共成像点道集(ODCIG)和角度域共成像点道集(ADCIG).由于ODCIG是一种能量聚焦型道集,且在复杂介质条件下存在运动学假象,使其在MVA中的应用受到限制.ADCIG的出现解决了这些问题,它能够适应射线传播的多路径现象,避免假象的产生,波动方程偏移得到的ADCIG被证明是没有假象的道集,也被认为是当前最为合理的道集.论文在CMP域,利用双平方根算子对记录波场进行反向延拓,因为双平方根算子偏移具有倾角假频少、边界处理简单、无需求取震源子波、无需考虑偏移孔径问题以及计算效率高等特点;在频率-波数域将偏移距信息映射到角度域得到ADCIG.ADCIG的提取过程实际是转化了地震数据中的多偏移距信息,本质上,它仍旧是对地震数据中多偏移距信息的体现.最后论文将ADCIG道集应用在SEG/EAGE岩丘模型中,结果表明,不同反射角下的ADCIG可以对地下不同的区域进行成像,且角度域成像具有地震波成像剖面分辨率高,边界干扰较小等特点.
In the field of migration velocity analysis, the common imaging point gathers are very important to the migration velocity analysis (MVA). At present, the common imaging gathers for offset velocity analysis mainly include offset imaging ODCIG and ADCIG. Since ODCIG is an energy-focused gathers and kinematic artifacts in complex media conditions, its application in MVA is limited.ADCIG These problems can be solved by adapting to the multi-path phenomenon of ray propagation and avoiding the appearance of artifacts. The ADCIG obtained by the wave equation migration is proved to be a set without illusion, and is also considered to be the most reasonable set of gathers. In the CMP domain, the double square root operator is used to reverse the recorded wavefield. Because the bi-square root operator has few diplane shifts and the boundary is simple to deal with, there is no need to take source wavelets, irrespective of the offset aperture problem and And the calculation efficiency is high.The ADCIG is obtained by mapping the offset information to the angle domain in the frequency-wavenumber domain. The extraction process of ADCIG actually transforms the multi-offset information in the seismic data. In essence, More partial And the information is reflected.Finally, the paper applied ADCIG gathers to the SEG / EAGE rock mound model. The results show that ADCIG with different reflection angles can image different regions of the earth, and the angle domain imaging has high seismic imaging profile resolution , Less interference and other characteristics of the border.