摘要
目前有两种有效的时变子波提取方法:将非平稳地震记录划分时窗后,每段可视为近似平稳地震记录提取子波;将非平稳地震记录变换到时频域进行分析,逐点提取时变子波。第一种方法难以准确地提取时变子波振幅,第二种方法尚不能准确地提取时变子波相位。为此,将上述两种方法结合,提出一种时频分析与自适应分段相结合的时变子波提取方法。具体方法流程为:首先利用时频域二次谱模拟方法提取时变子波振幅谱;其次采用自适应分段法提取每段子波相位,并将相位延拓至每一时刻以解决时变振幅与分段相位匹配问题;最后将提取的振幅与延拓后的相位逐点合并,形成一种基于时频域二次谱模拟及自适应分段相融合的时变子波提取方法。对非平稳地震记录提取时变子波后,通过反演得到反射系数序列,并结合评价准则对反射系数序列进行评价,进而量化评价子波提取的准确性。仿真数据和实际资料的处理测试表明,本文的时变子波提取方法同时考虑了地震信号在地下传播时每个时刻发生的振幅和相位畸变,能够很好地适应实际地震资料的非平稳性,并能得到较为准确的子波估计结果。
There are two effective methods of time-varying seismic wavelet extraction. First, after dividing the non-stationary seismogram into several time windows, the seismogram in each window can be treated as stationary one and then the seismic wavelets are extracted piecewise. Second, the non-stationary seismogram is transformed into time-frequency domain and the time-varying wavelets are extracted at each time point. To solve the problems that both two methods are difficult to extract the accurate amplitude and phase spectra of time-varying wavelets simultaneously, this paper presents a time-varying wavelet extraction method based on time-frequency analysis and adaptive segmentation, in which amplitude spectra are extracted by quadratic spectrum modeling in time-frequency domain and segmented phase spectra are extracted by adaptive molecular decomposition method. In order to solve the problem of matching time-varying amplitude spectra and segmented phase spectra, we extent the segmented phase spectra to every time point, and then the time-varying wavelets can be estimated completely and accurately by combining the amplitude and phase spectra at each time point. The reflection coefficient sequence can be inversed from non-stationary seismogram by using extracted time-varying wavelets and evaluated based on evaluation criteria. In this way, the accuracy of time-varying wavelet extraction can be evaluated quantitatively. Simulation and real data processing results show that, taking the distortion of amplitude and phase into consideration when the seismic signal spreads in underground, the proposed method can adapt well to the non-stationary nature of actual seismic data and obtain time-varying seismic wavelets accurately. © 2016, Editorial Department OIL GEOPHYSICAL PROSPECTING. All right reserved.
出处
《石油地球物理勘探》
EI
CSCD
北大核心
2016年第5期850-862,833,共13页
Oil Geophysical Prospecting
基金
中国石化地球物理重点实验室开放基金(33550006-15-FW2099-0033)
中国石油大学(华东)研究生创新工程资助项目(YCX2015050)联合资助
关键词
非平稳地震记录
时频分析
自适应分段
子波提取
评价准则
Data handling
Domain decomposition methods
Extraction
Frequency domain analysis
Seismic waves
Seismology
Wavelet decomposition
