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    基于Shearlet变换的自适应阈值迭代多震源数据分离方法及应用

    A shearlet transform-based adaptive threshold iteration method for simultaneous-source data separation and its application

    • 摘要: 多震源采集技术与传统采集技术相比,在提高采集效率和降低生产成本方面有着显著的优势,但其采集得到的地震数据会出现波场混叠现象,如何消除这一现象成为了该技术应用的难点。在多震源数据中有效信号和混叠噪声在非共炮点道集存在相干性差异,这种差异可以两者在Shearlet变换域的稀疏度进行表征。因此提出了基于Shearlet变换的自适应阈值迭代分离算法来分离多震源数据,从而确保后续地震数据处理和成像的效果。在研究过程中将共检波点道集的伪分离多震源数据转换到Shearlet域进行稀疏表示,针对不同尺度下Shearlet域有效信号和混叠噪声的分布特征,引入自适应贝叶斯阈值估计,利用收缩混叠噪声的变换系数来分离混叠噪声。采用迭代的方式可以保证该算法能够逐步优化分离结果。理论数据以及实际地震数据的多震源分离试算均取得了较好的分离结果。

       

      Abstract: Despite its significant advantages over conventional methods in terms of efficiency and cost, the simultaneous-source technique faces the challenge of wavefield aliasing that hinders its application. Effective signals and aliased noises in simultaneous-source data exhibit the differences in coherence on non-common shot gathers. These differences can be characterized by their respective sparsity in the shearlet transform domain. Therefore, this paper proposes an adaptive threshold iteration algorithm based on the shearlet transform for data separation, with the objective of ensuring the quality of subsequent seismic data processing and imaging. The algorithm begins by transforming the pseudo-separated simultaneous-source data on common receiver gathers into the shearlet domain for a sparse representation. Leveraging the distinct distribution characteristics of effective signals and aliased noises in the shearlet domain across different scales, aliased noises are separated by introducing an adaptive Bayesian threshold estimation to shrink the noise-related transformation coefficients. An iterative strategy is incorporated into the algorithm to gradually optimize the separation results. Synthetic and field data tests demonstrate the good performance of the proposed algorithm in simultaneous-source data separation.

       

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