Elastic full waveform inversion with probabilistic petrophysical clustering
Elastic full waveform inversion with probabilistic petrophysical clustering
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DOI：
10.1111/1365-2478.12910
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发表时间：
2020-01
影响因子：
2.6
通讯作者：
O. Aragao;P. Sava
中科院分区：
文献类型：
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作者：
O. Aragao;P. Sava
全波形反演旨在利用地震数据提供的所有信息，提供地下参数的高分辨率模型。然而，多参数全波形反演受到参数之间固有的权衡和由于全波形反演的高度非线性性质而产生的不适定性的影响。此外，如果初始模型与最优解相去甚远，利用弹性全波形反演恢复的模型也会受到局部最小值的约束。此外，纯粹基于记录数据和建模数据之间的不匹配的目标函数可能尊重地震数据，但忽略了地质背景。因此，反演模型可能在地质上不一致，不能代表可行的岩性单位。我们建议，通过基于多个概率密度函数的惩罚函数将岩石物理信息明确地纳入反演，可以缓解上述所有困难，其中每个概率密度函数代表具有不同性质的不同岩性。我们将岩性单元视为簇，并使用无监督K均值聚类将岩石物理信息划分为不同岩性的不同单元，这些单元不易区分。通过几个综合实例，我们证明了所提出的框架可以将全波形反演到弹性模型，这种模型优于不包含岩石物理信息或基于单一概率密度函数的概率惩罚函数获得的模型。
Full waveform inversion aims to use all information provided by seismic data to deliver high‐resolution models of subsurface parameters. However, multiparameter full waveform inversion suffers from an inherent trade‐off between parameters and from ill‐posedness due to the highly non‐linear nature of full waveform inversion. Also, the models recovered using elastic full waveform inversion are subject to local minima if the initial models are far from the optimal solution. In addition, an objective function purely based on the misfit between recorded and modelled data may honour the seismic data, but disregard the geological context. Hence, the inverted models may be geologically inconsistent, and not represent feasible lithological units. We propose that all the aforementioned difficulties can be alleviated by explicitly incorporating petrophysical information into the inversion through a penalty function based on multiple probability density functions, where each probability density function represents a different lithology with distinct properties. We treat lithological units as clusters and use unsupervised K‐means clustering to separate the petrophysical information into different units of distinct lithologies that are not easily distinguishable. Through several synthetic examples, we demonstrate that the proposed framework leads full waveform inversion to elastic models that are superior to models obtained either without incorporating petrophysical information, or with a probabilistic penalty function based on a single probability density function.