52 research outputs found
Block sweeping methods (source code)
No full text<p>This is a library of algorithms for the eikonal equation solution. It includes implementations of proposed parallel block sweeping methods [1] optimized for multicore CPUs. These methods are based on the fast sweeping method (FSM) [2] and the locking sweeping method (LSM) [3] numerical algorithms. Proposed methods achieve high parallel efficiency due to optimization of task synchronization and CPU cache use. The library also includes implementations of FSM and LSM as well as another parallel algorithm DFSM presented in [4]. For more information see conference abstract [1], we have also submitted an extended article for review and publication and are hoping to publish it in 2017. We are planning to improve this library in the future, for latest versions go to https://github.com/aanikitin/seis-eikonal.</p>
<p>References:</p>
<p>1) Nikitin Alexandr A., Serdyukov Alexandr S., Duchkov Anton A. Optimization of parallel sweeping methods of numerical computation of seismic wave travel times for shared memory computing systems // ИНТЕРЭКСПО ГЕО-СИБИРЬ. – 2016. – V. 2. – N. 1. – P. 241-245.</p>
<p>2) Zhao, H.: A fast sweeping method for eikonal equations. Mathematics of computation 74(250), 603-627 (2005)</p>
<p>3) Bak, S., McLaughlin, J., Renzi, D.: Some improvements for the fast sweeping method. SIAM Journal on Scientific Computing 32(5), 2853-2874 (2010)</p>
<p>4) Detrixhe, M., Gibou, F., Min, C.: A parallel fast sweeping method for the eikonal equation. Journal of Computational Physics 237, 46-55 (2013)</p>
Timing shifts retrieval for the multi-well downhole microseismic monitoring in isotropic and anisotropic (VTI) media
No full textInfluence of perforation shot geometry on estimation of anisotropic (HTI) parameters in microseismic monitoring
No full text
Extended structure tensors for multiple directionality estimation
No full textStandard structure tensors provide a robust way of directionality estimation of waves (or edges) but only for the case when they do not intersect. In this work, a structure tensor extension using a one-way wave equation is proposed as a tool for estimating directionality in seismic data and images in the presence of conflicting dips. Detection of two intersecting waves is possible in a two-dimensional case. In three dimensions both two and three intersecting waves can be detected. Moreover, a method for directionality filtering using the estimated directions is proposed. This method makes use of the ideas of a one-way wave equation but can be applied to generic images not related to wave propagation
Sparse wave-packet representations and seismic imaging
No full textIn this paper we introduce a new algorithm for seismic imaging based on the flow out of Gaussian wave packets. We follow the standard strategy of decomposing data into wave packets and flowing them out along rays to approximate the downward wavefield extrapolation, and finally applying an imaging condition. We revisit each computational step to gain efficiency. Furthermore, we develop procedure for seismic data decomposition in order to obtain highly sparse representations with Gaussian wave packets. As a result we get fast algorithm heavily exploiting sparse data representation and analytic description of Gaussian wave packets. We tests our algorithm on synthetic example of migrating common-shot gather
The structure-tensor analysis for optimal microseismic data partial stack
No full textMicroseismic monitoring of hydrofrac is an actively developing technology utilizing various acquizition arrays. In this paper we consider processing of microseismic data recorded by specific surface network geometry-patch arrays (far separated local receiver groups). The project aim is to produce an optimal partial stacking of the data within patches for improving a signal to noise ratio for microseismic events detection and location. We propose to use a structure-tensor analysis for estimating directions of coherency in the data, which can be used for data stacking for each patch. Unlike to the standard slantstacking method, we do not scan all possible directions, but receive them as eigenvectors of the structure tensor. We used the synthetic data for testing our approach in presence of random and coherent noise, in the case of interfering events. The testing showed that the structure-tensor analysis provides robust coherent summation results. We also discuss the usefulness of the structure-tensor attributes for detecting (triggering) the arriving wave and separating body wave from surface waves based on the apparent velocity
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