Separating Simultaneous Seismic Sources Using Robust Inversion of Radon and Migration Operators

Separating Simultaneous Seismic Sources Using Robust Inversion of Radon and Migration Operators PDF Author: Amr Ahmed Mahmoud Ibrahim
Publisher:
ISBN:
Category : Inversion (Geophysics)
Languages : en
Pages : 167

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Book Description
The advent of high density 3D wide azimuth survey configurations has greatly increased the cost of seismic acquisition. Simultaneous source acquisition presents an opportunity to decrease costs by reducing the survey time. Source time delays are typically long enough for seismic reflection energy to decay to negligible levels before firing another source. Simultaneous source acquisition abandons this minimum time restriction and allows interference between seismic sources to compress the survey time. Seismic data processing methods must address the interference introduced by simultaneous overlapping sources. Simultaneous source data are characterized by high amplitude interference artefacts that may be stronger than the primary signal. These large amplitudes are due to the time delay between sources and the rapid decay of seismic energy with arrival time. Therefore, source interference will appear as outliers in denoising algorithms that make use of a Radon transform. This will reduce the accuracy of Radon transform de-noising especially for weak signals. Formulating the Radon transform as an inverse problem with an L1 misfit makes it robust to outliers caused by source interference. This provides the ability to attenuate strong source interference while preserving weak underlying signal. In order to improve coherent signal focusing, an apex shifted hyperbolic Radon transform (ASHRT) is used to remove source interferences. ASHRT transform basis functions are tailored to match the travel time hyperbolas of reflections in common receiver gathers. However, the ASHRT transform has a high computational cost due to the extension of the model dimensions by scanning for apex locations. By reformulating the ASHRT operator using a Stolt migration/demigration kernel that exploits the Fast Fourier Transform (FFT), the computational efficiency of the operator is drastically improved. Moreover, the computational efficiency of the Stolt-based ASHRT operator allows us to extend the model dimension to fit seismic diffractions with the same accuracy as seismic reflections. The Asymptote and Apex Shifted Hyperbolic Radon Transform (AASHRT) can better focus diffracted energy by extending the basis functions to account for the asymptote time shift associated with diffractions. This transform is used to interpolate synthetic data that contain significant amount of seismic diffractions. The results of the interpolation tests show that the AASHRT transform is a powerful tool for interpolating seismic diffractions.

Separating Simultaneous Seismic Sources Using Robust Inversion of Radon and Migration Operators

Separating Simultaneous Seismic Sources Using Robust Inversion of Radon and Migration Operators PDF Author: Amr Ahmed Mahmoud Ibrahim
Publisher:
ISBN:
Category : Inversion (Geophysics)
Languages : en
Pages : 167

Get Book Here

Book Description
The advent of high density 3D wide azimuth survey configurations has greatly increased the cost of seismic acquisition. Simultaneous source acquisition presents an opportunity to decrease costs by reducing the survey time. Source time delays are typically long enough for seismic reflection energy to decay to negligible levels before firing another source. Simultaneous source acquisition abandons this minimum time restriction and allows interference between seismic sources to compress the survey time. Seismic data processing methods must address the interference introduced by simultaneous overlapping sources. Simultaneous source data are characterized by high amplitude interference artefacts that may be stronger than the primary signal. These large amplitudes are due to the time delay between sources and the rapid decay of seismic energy with arrival time. Therefore, source interference will appear as outliers in denoising algorithms that make use of a Radon transform. This will reduce the accuracy of Radon transform de-noising especially for weak signals. Formulating the Radon transform as an inverse problem with an L1 misfit makes it robust to outliers caused by source interference. This provides the ability to attenuate strong source interference while preserving weak underlying signal. In order to improve coherent signal focusing, an apex shifted hyperbolic Radon transform (ASHRT) is used to remove source interferences. ASHRT transform basis functions are tailored to match the travel time hyperbolas of reflections in common receiver gathers. However, the ASHRT transform has a high computational cost due to the extension of the model dimensions by scanning for apex locations. By reformulating the ASHRT operator using a Stolt migration/demigration kernel that exploits the Fast Fourier Transform (FFT), the computational efficiency of the operator is drastically improved. Moreover, the computational efficiency of the Stolt-based ASHRT operator allows us to extend the model dimension to fit seismic diffractions with the same accuracy as seismic reflections. The Asymptote and Apex Shifted Hyperbolic Radon Transform (AASHRT) can better focus diffracted energy by extending the basis functions to account for the asymptote time shift associated with diffractions. This transform is used to interpolate synthetic data that contain significant amount of seismic diffractions. The results of the interpolation tests show that the AASHRT transform is a powerful tool for interpolating seismic diffractions.

Simultaneous Source Seismic Acquisition

Simultaneous Source Seismic Acquisition PDF Author: Ray Abma
Publisher: SEG Books
ISBN: 1560803789
Category : Science
Languages : en
Pages : 220

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Book Description
This book introduces simultaneous source technology and helps those who practice it succeed. Although the book does not include all developments, which would have en­tailed a much longer treatise, this work is written through the lens of decades of experiences and allows readers to understand the development of independent simultaneous sourcing. The relationships between data acquisition and data processing are discussed because never before have they been so intertwined as in this area. In addition to describing the underlying technologies, this book also is a user-guide which discusses survey design and acquisition and decribes the sensitivities of the processing algorithms which can allow simultaneous source technology to succeed. The audience for this book includes acquisition and pro­cessing geophysicists who will work with these data as well as those who require only an overview of the state of the art; and, even though they may not need the full technical details, they may want to know the limitations and advantages of using simultaneous sources.

Projected Gradient Descent Methods for Simultaneous-source Seismic Data Processing

Projected Gradient Descent Methods for Simultaneous-source Seismic Data Processing PDF Author: Rongzhi Lin
Publisher:
ISBN:
Category : Geophysics
Languages : en
Pages : 0

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Book Description
Simultaneous-source acquisition is a seismic data acquisition technology that has become quite popular in recent years due to its economic advantages. Contrary to the conventional seismic acquisition, where one records the seismic response of only one source at a time, in simultaneous source acquisition, an array of receivers record the response of more than one source. The latter leads to a saving in acquisition time, but it creates new problems in subsequent data processing stages where each seismic record must correspond to the response of one single source. The basic idea for simultaneous source data processing is to separate the sources and thereby estimate the responses one would have acquired via a conventional seismic data acquisition. Then one can adopt a traditional seismic workflow to process and invert the seismic data. This thesis focuses on developing inversion schemes for separating simultaneous-source data. I pay particular attention to strategies based on the Projected Gradient Descent (PGD) method with a projection synthesized via robust denoising algorithms. First, I propose adopting a robust and sparse Radon transform to define a coherence pass projection operator to guarantee solutions that honour simultaneous source records. I show that a critical improvement in convergence is attainable when the coherence pass projection originates from a robust and sparse Radon transform. The latter is a consequence of having an iterative source separation algorithm that applies intense denoising to erratic blending noise in its initial iterations. In addition, I also propose an inversion scheme for simultaneous-source data separation based on a robust low-rank approximation algorithm. A robust Multichannel Singular Spectrum Analysis (MSSA) filtering is adopted as the projection operator to suppress source interferences in the frequency-space domain. The MSSA method is reformulated as a robust optimization problem that includes a low-rank Hankel matrix constraint, written as the product of two matrices of lower dimension obtained by the bifactored gradient descent (BFGD) method. In the second part of my thesis, I explore an inversion scheme for source separation and source reconstruction that honours actual source coordinates. The proposed method adopts a projected gradient descent optimization with a reduced-rank MSSA projection operator. I propose to adopt an Interpolated-MSSA (I-MSSA) to separate and reconstruct sources in situations where the acquired simultaneous source data correspond to sources with ar- arbitrary irregular-grid coordinates. Additionally, a faster and computational-efficient MSSA (FMSSA) algorithm was applied to speed up the method.

The Radon Transform and Medical Imaging

The Radon Transform and Medical Imaging PDF Author: Peter Kuchment
Publisher: SIAM
ISBN: 1611973287
Category : Computers
Languages : en
Pages : 238

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Book Description
This book surveys the main mathematical ideas and techniques behind some well-established imaging modalities such as X-ray CT and emission tomography, as well as a variety of newly developing coupled-physics or hybrid techniques, including thermoacoustic tomography. The Radon Transform and Medical Imaging emphasizes mathematical techniques and ideas arising across the spectrum of medical imaging modalities and explains important concepts concerning inversion, stability, incomplete data effects, the role of interior information, and other issues critical to all medical imaging methods. For nonexperts, the author provides appendices that cover background information on notation, Fourier analysis, geometric rays, and linear operators. The vast bibliography, with over 825 entries, directs readers to a wide array of additional information sources on medical imaging for further study.

Seismic Diffraction

Seismic Diffraction PDF Author: Tijmen Jan Moser
Publisher: SEG Books
ISBN: 1560803177
Category : Science
Languages : en
Pages : 823

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Book Description
The use of diffraction imaging to complement the seismic reflection method is rapidly gaining momentum in the oil and gas industry. As the industry moves toward exploiting smaller and more complex conventional reservoirs and extensive new unconventional resource plays, the application of the seismic diffraction method to image sub-wavelength features such as small-scale faults, fractures and stratigraphic pinchouts is expected to increase dramatically over the next few years. “Seismic Diffraction” covers seismic diffraction theory, modeling, observation, and imaging. Papers and discussion include an overview of seismic diffractions, including classic papers which introduced the potential of diffraction phenomena in seismic processing; papers on the forward modeling of seismic diffractions, with an emphasis on the theoretical principles; papers which describe techniques for diffraction mathematical modeling as well as laboratory experiments for the physical modeling of diffractions; key papers dealing with the observation of seismic diffractions, in near-surface-, reservoir-, as well as crustal studies; and key papers on diffraction imaging.

Petroleum Abstracts

Petroleum Abstracts PDF Author:
Publisher:
ISBN:
Category : Petroleum
Languages : en
Pages : 1752

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Book Description


Seismic Data Processing

Seismic Data Processing PDF Author: Özdoğan Yilmaz
Publisher:
ISBN: 9780931830419
Category : Seismic prospecting
Languages : en
Pages : 526

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Book Description


Seismic Inversion

Seismic Inversion PDF Author: Gerard T. Schuster
Publisher: SEG Books
ISBN: 156080341X
Category : Science
Languages : en
Pages : 377

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Book Description
This book describes the theory and practice of inverting seismic data for the subsurface rock properties of the earth. The primary application is for inverting reflection and/or transmission data from engineering or exploration surveys, but the methods described also can be used for earthquake studies. Seismic Inversion will be of benefit to scientists and advanced students in engineering, earth sciences, and physics. It is desirable that the reader has some familiarity with certain aspects of numerical computation, such as finite-difference solutions to partial differential equations, numerical linear algebra, and the basic physics of wave propagation. For those not familiar with the terminology and methods of seismic exploration, a brief introduction is provided. To truly understand the nuances of seismic inversion, we have to actively practice what we preach (or teach). Therefore, computational labs are provided for most of the chapters, and some field data labs are given as well.

Mathematics of Multidimensional Seismic Imaging, Migration, and Inversion

Mathematics of Multidimensional Seismic Imaging, Migration, and Inversion PDF Author: N. Bleistein
Publisher: Springer Science & Business Media
ISBN: 9780387950617
Category : Mathematics
Languages : en
Pages : 546

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Book Description
For more than 80 years, the oil and gas industry has used seismic methods to construct images and determine physical characteristics of rocks that can yield information about oil and gas bearing structures in the earth. This book presents the different seismic data processing methods, also known as seismic "migration," in a unified mathematical way. The book serves as a bridge between the applied math and geophysics communities by presenting geophysicists with a practical introduction to advanced engineering mathematics, while presenting mathematicians with a window into the world of the mathematically sophisticated geophysicist.

Seismic Migration

Seismic Migration PDF Author: A. J. Berkhout
Publisher:
ISBN:
Category : Seismic waves
Languages : en
Pages : 296

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Book Description