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Using a machine learning proxy for localization in ensemble data assimilation
Computational Geosciences ( IF 2.5 ) Pub Date : 2021-02-12 , DOI: 10.1007/s10596-020-10031-0
Johann M. Lacerda , Alexandre A. Emerick , Adolfo P. Pires

Ensemble data assimilation methods, particularly iterative forms of ensemble smoother, are very useful assisted history matching techniques. One of the main challenges in the application of these methods is the excessive variance loss due to sampling errors occasioned by the limited size ensembles used in practical cases. The standard procedure to mitigate this problem is called distance-based localization. However, in this case, the data assimilation performance becomes highly dependent on the choice of the localization region. Moreover, there are several relevant examples of non-local model parameters and data types, in which cases, distance-based localization does not apply. This paper proposes a distance-free localization procedure that combines a least-squares support vector (LS-SVR) proxy with a non-isotropic tapering function proposed in the literature. We tested the proposed method in two versions of the PUNQ-S3 problem. In the first version, we tested the method to localize scalar (non-local) parameters. The results show relevant improvements, especially in terms of preserving the posterior variance of the ensemble compared to methods investigated in Lacerda et al. (J. Pet. Sci. Eng. 172,690–706, 2019). The second version considered the problem of localization of grid parameters. In this case, the proposed method outperformed a distance-based localization approach proposed in the literature.



中文翻译:

使用机器学习代理对集成数据同化进行本地化

集合数据同化方法,特别是整体平滑器的迭代形式,是非常有用的辅助历史匹配技术。这些方法应用中的主要挑战之一是由于实际情况中使用的有限大小的集合所引起的采样误差导致的过度方差损失。缓解此问题的标准过程称为基于距离的定位。但是,在这种情况下,数据同化性能高度依赖于定位区域的选择。此外,还有一些非本地模型参数和数据类型的相关示例,在这种情况下,基于距离的本地化不适用。本文提出了一种无距离定位方法,该方法将最小二乘支持向量(LS-SVR)代理与文献中提出的非各向同性渐缩函数结合在一起。我们在两个版本的PUNQ-S3问题中测试了该方法。在第一个版本中,我们测试了将标量(非本地)参数本地化的方法。结果显示出相关的改进,特别是与Lacerda等人研究的方法相比,在保留合奏的后方方差方面。(J. Pet。Sci.Eng.172,690–706,2019)。第二个版本考虑了网格参数本地化的问题。在这种情况下,所提出的方法优于文献中提出的基于距离的定位方法。我们测试了本地化标量(非本地)参数的方法。结果显示出相关的改进,特别是与Lacerda等人研究的方法相比,在保留合奏的后方方差方面。(J. Pet。Sci.Eng.172,690–706,2019)。第二个版本考虑了网格参数本地化的问题。在这种情况下,所提出的方法优于文献中提出的基于距离的定位方法。我们测试了本地化标量(非本地)参数的方法。结果显示出相关的改进,特别是与Lacerda等人研究的方法相比,在保留合奏的后方方差方面。(J. Pet。Sci.Eng.172,690–706,2019)。第二个版本考虑了网格参数本地化的问题。在这种情况下,所提出的方法优于文献中提出的基于距离的定位方法。

更新日期:2021-02-12
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