Efficient waveform inversion and imaging: A strategy for selecting temporal frequencies
Efficient waveform inversion and imaging: A strategy for selecting temporal frequencies
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DOI：
10.1190/1.1649391
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发表时间：
2004
期刊：
影响因子：
3.3
通讯作者：
L. Sirgue;R. Pratt
中科院分区：
文献类型：
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作者：
L. Sirgue;R. Pratt
叠前偏移和/或反演可以在时域或频域中实现。在频域中，可以用比采样定理所规定的采样间隔大得多的采样间隔来离散化频率，并且仍然获得在深度域中不遭受混叠（环绕）的成像结果。当偏移量范围可用时，可以减少输入频率的选择;这在目标的波数覆盖中产生了信息冗余。为了优化这些信息的使用，我们定义了一种新的离散化策略，该策略取决于地表地震勘探中存在的最大有效偏移：偏移范围越大，所需的频率就越少。该策略在均匀的一维地球中是精确的，通过利用正常时差（NMO）校正和偏移（通常被认为对成像不利）中的图像拉伸的众所周知的效果来选择频率。该策略在更一般的地球模型中也很有用：我们将其应用于2D Marmousi模型，并仅使用三个输入频率恢复连续范围的波数。Marmousi反演结果准确地预测了所有其他数据频率，证明了数据的冗余性。
Prestack migration and/or inversion may be implemented in either the time or the frequency domain. In the frequency domain, it is possible to discretize the frequencies with a much larger sampling interval than that dictated by the sampling theorem and still obtain an imaging result that does not suffer from aliasing (wrap around) in the depth domain. The selection of input frequencies can be reduced when a range of offsets is available; this creates a redundancy of information in the wavenumber coverage of the target. In order to optimize the use of this information, we define a new discretization strategy that depends on the maximum effective offset present in the surface seismic survey: the larger the range of offsets, the fewer frequencies are required. The strategy, exact in a homogeneous 1D earth, selects frequencies by making use of the well-known effect of image stretch in normal-moveout (NMO) correction and in migration (usually considered detrimental for the imaging). The strategy is also useful in more general earth models: we apply it to the 2D Marmousi model and recover a continuous range of wavenumbers using only three input frequencies. The Marmousi inversion result accurately predicts all other data frequencies, demonstrating the redundancy of the data.