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公开(公告)号：US20210223425A1
公开(公告)日：2021-07-22
申请号：US17247503
申请日：2020-12-14
Applicant: ExxonMobil Upstream Research Company
Inventor： Junzhe Sun , Valeriy V. Brytik , Lingxiao Zhang , Erik R. Neumann
Abstract: A method for approximating an inverse Hessian is provided. One methodology to generate the inverse Hessian is to precondition the gradient, such as by using point-spread function deconvolution, T-power, or source-illumination compensation, prior to using non-stationary matching filters (NMF) to generate the inverse Hessian. Various types of NMF are contemplated, including using filters for different windows in the subsurface or using filters assigned to specific locations in the subsurface. Further, the number of filters for NMF may vary from iteration to iteration. For example, the filters assigned to the specific locations in the subsurface may be generated in a multi-scale manner, in which an initial iteration uses longer scale/longer wavelength features for inversion and subsequent iterations use finer scale/smaller wavelength features for inversion.
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2.发明申请公开(公告)号：US20210239879A1
公开(公告)日：2021-08-05
申请号：US17247528
申请日：2020-12-15
Applicant: ExxonMobil Upstream Research Company
Inventor： Valeriy V. Brytik , Junzhe Sun , Carey M. Marcinkovich , Hong Zhao , Erik R. Neumann
Abstract: A method for partitioning a search direction when using least squares reverse time migration (LSRTM) is provided. LSRTM may be used iteratively in order to improve imaging accuracy. As part of LSRTM, multiple local line searches may be performed. In particular, image space may be partitioned, such as by using a set of masks. The search direction, such as the gradient, may be partitioned using the set of masks. Local line searches may be performed for each partition of the search direction, resulting in finding respective line search constants. The respective line search constants may then be used for iterating the model in order to improve imaging accuracy.
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