Crosscorrelation migration of microseismic source locations with hybrid imaging condition

Geophysics ◽  
2021 ◽  
pp. 1-49
Author(s):  
Shaojiang Wu ◽  
Yibo Wang ◽  
Fei Xie ◽  
Xu Chang
Keyword(s):  
Cross Correlation ◽  
Hybrid Imaging ◽  
Hydraulic Fractures ◽  
Imaging Condition ◽  
Time Scanning ◽  
Comparison Results ◽  
Excitation Time ◽  
Seismic Location ◽  
Location Methods ◽  
Selection Of

Locating microseismic sources is critical to monitor the hydraulic fractures that occur during fluid extraction/injection in unconventional oil or gas exploration. Waveform-based seismic location methods can reliably and automatically image weak microseismic source locations without phase picking. Among them, the cross-correlation migration (CCM) method can avoid excitation time scanning by generating virtual gathers. We propose a CCM location method based on the hybrid imaging condition (HIC). There are four main steps in the implementation of this method: 1) selection of receivers with good azimuthal coverage; 2) generation of virtual gathers by correlating the reference receiver with the rest of the receivers; 3) summation of back-projections in the virtual gathers; and 4) multiplication of all summations. The CCM-HIC method was tested on synthetic and field datasets, and the results were compared with those obtained by conventional summation imaging condition (SIC) and multiplication imaging condition (MIC). The comparison results demonstrate that the CCM-HIC is sufficiently robust to obtain better stability and higher spatial resolution image of source location, despite the presence of strong noise.

Multi-Component Seismic Wave Field Prestack Reverse-Time Depth Migration

2013 ◽  
Vol 868 ◽  
pp. 11-14
Author(s):  
Jia Jia Yang ◽  
Bing Shou He ◽  
Jian Zhong Zhang
Keyword(s):  
Wave Equation ◽  
Elastic Wave ◽  
Cross Correlation ◽  
Reverse Time ◽  
Reverse Time Migration ◽  
Elastic Wave Equation ◽  
Imaging Condition ◽  
Depth Migration ◽  
Time Migration ◽  
Excitation Time

Based on the elastic wave equation, high-order finite-difference schemes for reverse-time extrapolation in the space of staggered grid and the perfectly matched layer (PML) absorbing boundary condition for the equation are derived. Prestack reverse-time depth migration (RTM) of elastic wave equation using the excitation time imaging condition and normalized cross-correlation imaging condition is carried out. Numerical experiments show that reverse-time migration is not limited for the angle of incidence and dramatic changes in lateral velocity. The reverse-time migration results of normalized cross-correlation imaging condition give the better effect than that of excitation time imaging condition.

Energy Efficiency Analysis in ERA using NFL-BA Algorithm

2020 ◽  
pp. 340-348
Author(s):  
Palky Mehta ◽  
H. L. Sharma
Keyword(s):  
Cluster Head ◽  
Vital Role ◽  
Wireless Sensor ◽  
Energy Usage ◽  
Cluster Heads ◽  
Comparison Results ◽  
Current Scenario ◽  
Energy Efficiency Analysis ◽  
Selection Of

In the current scenario of Wireless Sensor Network (WSN), power consumption is the major issue associated with nodes in WSN. LEACH technique plays a vital role of clustering in WSN and reduces the energy usage effectively. But LEACH has its own limitation in order to search cluster head nodes which are randomly distributed over the network. In this paper, ERA-NFL- BA algorithm is being proposed for selects the cluster heads in WSN. This algorithm help in selection of cluster heads can freely transform from global search to local search. At the end, a comparison has been done with earlier researcher using protocol ERA-NFL, which clearly shown that proposed Algorithm is best suited and from comparison results that ERA-NFL-BA has given better performance.

Acoustic modeling and migration of stacked cross‐hole data

Geophysics ◽  
1988 ◽  
Vol 53 (4) ◽  
pp. 492-500 ◽  
Author(s):  
Xianhuai Zhu ◽  
George A. McMechan
Keyword(s):  
Line Source ◽  
Synthetic Data ◽  
Point Sources ◽  
Scale Model ◽  
Model Data ◽  
Reverse Time ◽  
Imaging Condition ◽  
Surface Survey ◽  
Excitation Time ◽  
And Migration

Prestack computations for cross‐hole data are relatively expensive, as they are for prestack surface survey data. It is therefore of interest to develop methodologies for modeling and processing stacked cross‐hole data. In this context, stacking is over sources, not midpoints. Modeling with a line source produces data that are equivalent (by Huygen’s principle) to those obtained by stacking over a line of point sources. Reverse‐time finite‐difference migration may be applied to the resulting stacked section by generalizing the excitation‐ time imaging condition for a point source to a line source. Illustrations include successful applications to both synthetic data and scale‐model data.

scholarly journals A Spectral Clustering Algorithm Improved by P Systems

2018 ◽  
Vol 13 (5) ◽  
pp. 759-771 ◽  
Author(s):  
Guangchun Chen ◽  
Juan Hu ◽  
Hong Peng ◽  
Jun Wang ◽  
Xiangnian Huang
Keyword(s):  
Spectral Clustering ◽  
Clustering Algorithm ◽  
Membrane Computing ◽  
Clustering Algorithms ◽  
P System ◽  
Comparison Results ◽  
Clustering Effect ◽  
Computing Framework ◽  
Spectral Clustering Algorithm ◽  
Selection Of

Using spectral clustering algorithm is diffcult to find the clusters in the cases that dataset has a large difference in density and its clustering effect depends on the selection of initial centers. To overcome the shortcomings, we propose a novel spectral clustering algorithm based on membrane computing framework, called MSC algorithm, whose idea is to use membrane clustering algorithm to realize the clustering component in spectral clustering. A tissue-like P system is used as its computing framework, where each object in cells denotes a set of cluster centers and velocity-location model is used as the evolution rules. Under the control of evolutioncommunication mechanism, the tissue-like P system can obtain a good clustering partition for each dataset. The proposed spectral clustering algorithm is evaluated on three artiffcial datasets and ten UCI datasets, and it is further compared with classical spectral clustering algorithms. The comparison results demonstrate the advantage of the proposed spectral clustering algorithm.

scholarly journals LAGUERRE-GAUSS FILTERS IN REVERSE TIME MIGRATION IMAGE RECONSTRUCTION

2018 ◽  
Vol 35 (2) ◽  
Author(s):  
Juan Guillermo Paniagua Castrillón ◽  
Olga Lucia Quintero Montoya ◽  
Daniel Sierra-Sosa
Keyword(s):  
Cross Correlation ◽  
Synthetic Data ◽  
Low Frequency ◽  
Frequency Noise ◽  
Reverse Time ◽  
Reverse Time Migration ◽  
Imaging Condition ◽  
Time Migration ◽  
Migration Imaging ◽  
Gauss Transform

ABSTRACT. Reverse time migration (RTM) solves the acoustic or elastic wave equation by means of the extrapolation from source and receiver wavefield in time. A migrated image is obtained by applying a criteria known as imaging condition. The cross-correlation between source and receiver wavefields is the commonly used imaging condition. However, this imaging condition produces spatial low-frequency noise, called artifacts, due to the unwanted correlation of the diving, head and backscattered waves. Several techniques have been proposed to reduce the artifacts occurrence. Derivative operators as Laplacian are the most frequently used. In this work, we propose a technique based on a spiral phase filter ranging from 0 to 2π, and a toroidal amplitude bandpass filter, known as Laguerre-Gauss transform. Through numerical experiments we present the application of this particular filter on three synthetic data sets. In addition, we present a comparative spectral study of images obtained by the zero-lag cross-correlation imaging condition, the Laplacian filtering and the Laguerre-Gauss filtering, showing their frequency features. We also present evidences not only with simulated noisy velocity fields but also by comparison with the model velocity field gradients that this method improves the RTM images by reducing the artifacts and notably enhance the reflective events. Keywords: Laguerre-Gauss transform, zero-lag cross-correlation, seismic migration, imaging condition. RESUMO. A migração reversa no tempo (RTM) resolve a equação de onda acústica ou elástica por meio da extrapolação a partir do campo de onda da fonte e do receptor no tempo. Uma imagem migrada é obtida aplicando um critério conhecido como condição de imagem. A correlação cruzada entre campos de onda de fonte e receptor é a condição de imagem comumente usada. No entanto, esta condição de imagem produz ruído espacial de baixa frequência, chamados artefatos, devido à correlação indesejada das ondas de mergulho, cabeça e retrodifusão. Várias técnicas têm sido propostas para reduzir a ocorrência de artefatos. Operadores derivados como Laplaciano são os mais utilizados. Neste trabalho, propomos uma técnica baseada em um filtro de fase espiral que varia de 0 a 2π, e um filtro passabanda de amplitude toroidal, conhecido como transformada de Laguerre-Gauss. Através de experimentos numéricos, apresentamos a aplicação deste filtro particular em três conjuntos de dados sintéticos. Além disso, apresentamos um estudo comparativo espectral de imagens obtidas pela condição de imagem de correlação cruzada atraso zero, a filtragem de Laplaciano e a filtragem Laguerre-Gauss, mostrando suas características de frequência. Apresentamos evidências não somente com campos simulados de velocidade ruidosa, mas também por comparação com os gradientes de campo de velocidade do modelo que este método melhora as imagens RTM, reduzindo os artefatos e aumentando notavelmente os eventos reflexivos. Palavras-chave: Transformação de Laguerre-Gauss, correlação cruzada atraso zero, migração sísmica, condição de imagem.

Different Flexibilities of 3D Scanners and Their Impact on Distinctive Applications

2020 ◽  
Vol 7 (1) ◽  
pp. 37-53 ◽  
Author(s):  
Mohd Javaid ◽  
Abid Haleem ◽  
Shahbaz Khan ◽  
Sunil Luthra
Keyword(s):  
Lead Time ◽  
3D Scanner ◽  
Analytical Hierarchical Process ◽  
Surgical Guides ◽  
Time Scanning ◽  
Different Types ◽  
3D Scanners ◽  
Support Software ◽  
Performance Ranking ◽  
Selection Of

3D scanners are supporting technology which offers a higher level of flexibility to create designs for ergonomic tooling, biocompatible surgical guides, and realistic prototypes and parts. Flexibility helps to reduce lead time, weight, cost, and product development time. Scanning technologies are in tandem with support software that helps a designer to (re)design products at a cheaper and faster rate. There is a need to understand different types of flexibilities and associated application of 3D scanner. In this article, we have conducted an extensive review of the available literature for identifying various flexibilities of 3D scanners and its applications. This research categorises 3D scanner flexibility and applications into five major types. From design to final quality inspection, these flexibilities play a significant role in industries and sectors to achieve optimum performance. Ranking of these flexibilities and their impact on different applications are accomplished using the analytical hierarchical process (AHP) with the help of expert opinion. The ranking of five significant flexibilities by using 3D scanners, undertaken through the AHP technique shows that scanning provides object flexibility at a higher level. The impacts of different flexibilities on applications are also weighted, and it shows that all flexibilities are enough to achieve application individually. This digital technology is helpful to create the customised product which is also helpful to achieve goals of Industry 4.0. It facilitates the customisation and has a significant impact on the design applications. This study provides an understanding of the 3D scanner in the context of flexibilities by identifying the different flexibilities it offers when used for different applications. Findings may assist developing a decision support system for the selection of 3D scanners for the different applications.

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