DETERMINATION OF AN OPTIMAL PROCESSING FLOW FOR THE SUPPRESSION OF FREE-SURFACE MULTIPLES IN REAL 2D MARINE DATA

The presence of multiple reflections is common in marine surveys due to the air-water interface. Multiples have significant energy and can mask deep reflectors, leading to the misinterpretation of seismic cross-sections. In this study, surface-related multiple elimination (SRME), predictive deconvolution in the domain τ − p domain and Radon and f − k filtering are used to eliminate surface multiples in real 2D marine data. These methods are applied in different combinations, and the results are analyzed with the aim of determining an optimal seismic processing flow for the removal of surface multiples. RESUMO: No levantamento marinho é comum a presença de reflexões múltiplas devido à interface ar-água. Essas reflexões múltiplas possuem energia considerável e podem mascarar reflexões primárias levando a erros de interpretação da seção sísmica. Neste trabalho é determinado um fluxo ótimo de processamento sísmico para atenuação de múltiplas de superfície. Os métodos de eliminação de múltiplas de superfície (SRME), deconvolução preditiva no domínio τ − p e as filtragens Radone f − k são aplicados a um dado marinho real 2D em diferentes combinações. Os resultados são analisados com objetivo de determinar um fluxo de processamento sísmico ótimo para atenuação de múltiplas de superfície.Palavras-chave: atenuação de múltiplas de superfície; SRME; filtragem Radon; deconvolução preditiva no domínio τ − p; filtragem f − k

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LONG-PERIOD SURFACE-RELATED MULTIPLE SUPPRESSION IN 2D MARINE SEISMIC DATA USING PREDICTIVE DECONVOLUTION AND COMBINATION OF SURFACE-RELATED MULTIPLE ELIMINATION AND PARABOLIC RADON FILTERING

10.32008/geolinks2021/b1/v3/30 ◽

2021 ◽

Author(s):

Pimpawee Sittipan ◽

Pisanu Wongpornchai

Keyword(s):

Seismic Data ◽

Seismic Reflection ◽

Petroleum Reservoirs ◽

The United States ◽

Multiple Reflections ◽

Long Period ◽

Predictive Deconvolution ◽

Short Period ◽

Marine Seismic ◽

Multiple Elimination

Some of the important petroleum reservoirs accumulate beneath the seas and oceans. Marine seismic reflection method is the most efficient method and is widely used in the petroleum industry to map and interpret the potential of petroleum reservoirs. Multiple reflections are a particular problem in marine seismic reflection investigation, as they often obscure the target reflectors in seismic profiles. Multiple reflections can be categorized by considering the shallowest interface on which the bounces take place into two types: internal multiples and surface-related multiples. Besides, the multiples can be categorized on the interfaces where the bounces take place, a difference between long-period and short-period multiples can be considered. The long-period surface-related multiples on 2D marine seismic data of the East Coast of the United States-Southern Atlantic Margin were focused on this research. The seismic profile demonstrates the effectiveness of the results from predictive deconvolution and the combination of surface-related multiple eliminations (SRME) and parabolic Radon filtering. First, predictive deconvolution applied on conventional processing is the method of multiple suppression. The other, SRME is a model-based and data-driven surface-related multiple elimination method which does not need any assumptions. And the last, parabolic Radon filtering is a moveout-based method for residual multiple reflections based on velocity discrimination between primary and multiple reflections, thus velocity model and normal-moveout correction are required for this method. The predictive deconvolution is ineffective for long-period surface-related multiple removals. However, the combination of SRME and parabolic Radon filtering can attenuate almost long-period surface-related multiple reflections and provide a high-quality seismic images of marine seismic data.

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MULTIPLE REFLECTIONS OF SEISMIC ENERGY

Geophysics ◽

10.1190/1.1437377 ◽

1948 ◽

Vol 13 (1) ◽

pp. 58-85 ◽

Cited By ~ 5

Author(s):

Raul F. Hansen ◽

Curtis H. Johnson

Keyword(s):

Cross Sections ◽

Average Velocity ◽

Quantitative Methods ◽

Seismic Energy ◽

Graphical Form ◽

Multiple Reflections ◽

The Earth ◽

Straight Line ◽

Considerable Work

This paper is a report of observations of multiple reflections in seismograph work in Argentina, of successful methods of identifying them, and of unsuccessful attempts to eliminate them. The paper begins with generalizations regarding the expectancy of multiples and develops geometrically (using straight‐line paths) the relation between multiples and their primary reflections for the cases of multiple reflection between a horizon and the surface and between two horizons, as regards time of reflection, dip and average velocity. The importance of a sharp reflecting contrast at the surface is emphasized, and it is concluded that the base of weathering may be more important in the formation of multiples than the surface of the earth. Early observations of multiple reflections from a volcanic flow and from a shallow basement are described. Other areas showed discordant data on the seismograms and cross sections, which, if due to multiples, could only be caused by multiple reflections from good sedimentary reflectors. In these areas a method for identifying both types of multiple reflections by their low average velocity as obtained by shooting reflection velocity‐profiles was developed, the work being facilitated by considerable knowledge of velocity and section from previous refraction shooting. Though this reflection velocity‐profile method is considered essential to positive and detailed identification of multiples, two methods of multiple identification using ΔT variations in continuous profiling are described and the results of considerable work with one of them are reported in graphical form, showing not only a separation of multiple from real reflections but also the determination of the true velocity‐depth function by means of the real reflections so segregated. Experiments are briefly described in which variations in size or depth of shot and variations in filters were not effective in reducing the ratio of multiple reflections to real reflections. The paper closes with suggestions for identifying multiple reflections by their abnormal curvatures in discontinuous, symmetrical‐spread dip shooting, and for using primitive qualitative methods where the topography or subsurface are not suited to the quantitative methods developed here.

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Analysis of STEM micrographs of thick objects

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081395 ◽

1978 ◽

Vol 36 (2) ◽

pp. 106-107

Author(s):

S. Golladay

Keyword(s):

Inelastic Scattering ◽

Multiple Scattering ◽

Mass Distribution ◽

Cross Sections ◽

Phase Contrast ◽

Image Point ◽

Contrast Effects ◽

Total Cross Sections ◽

Elastic And Inelastic Scattering

The theory of multiple scattering has been worked out by Groves and comparisons have been made between predicted and observed signals for thick specimens observed in a STEM under conditions where phase contrast effects are unimportant. Independent measurements of the collection efficiencies of the two STEM detectors, calculations of the ratio σe/σi = R, where σe, σi are the total cross sections for elastic and inelastic scattering respectively, and a model of the unknown mass distribution are needed for these comparisons. In this paper an extension of this work will be described which allows the determination of the required efficiencies, R, and the unknown mass distribution from the data without additional measurements or models. Essential to the analysis is the fact that in a STEM two or more signal measurements can be made simultaneously at each image point.

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A quantitative approach to inner shell losses

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010977x ◽

1978 ◽

Vol 36 (1) ◽

pp. 526-527 ◽

Cited By ~ 2

Author(s):

R.D. Leapman ◽

P. Rez ◽

D.F. Mayers

Keyword(s):

Energy Transfer ◽

Cross Section ◽

Cross Sections ◽

Accurate Determination ◽

Background Intensity ◽

Core Excitation ◽

Quantitative Basis ◽

Cross Section Differential ◽

Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

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Preparation And elemental analysis of ancient fibers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126846 ◽

1987 ◽

Vol 45 ◽

pp. 410-411

Author(s):

Allen Angel ◽

Kathryn A. Jakes

Keyword(s):

Cross Sections ◽

Physical Structure ◽

Energy Dispersive ◽

Archaeological Sites ◽

X Ray ◽

Long Term Storage ◽

Backscattered Electron ◽

Electron Imaging

Fabrics recovered from archaeological sites often are so badly degraded that fiber identification based on physical morphology is difficult. Although diagenetic changes may be viewed as destructive to factors necessary for the discernment of fiber information, changes occurring during any stage of a fiber's lifetime leave a record within the fiber's chemical and physical structure. These alterations may offer valuable clues to understanding the conditions of the fiber's growth, fiber preparation and fabric processing technology and conditions of burial or long term storage (1).Energy dispersive spectrometry has been reported to be suitable for determination of mordant treatment on historic fibers (2,3) and has been used to characterize metal wrapping of combination yarns (4,5). In this study, a technique is developed which provides fractured cross sections of fibers for x-ray analysis and elemental mapping. In addition, backscattered electron imaging (BSI) and energy dispersive x-ray microanalysis (EDS) are utilized to correlate elements to their distribution in fibers.

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Gender determination of caucasoid hair using image analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100146928 ◽

1993 ◽

Vol 51 ◽

pp. 216-217

Author(s):

T.B. Ball ◽

W.M. Hess

Keyword(s):

Image Analysis ◽

Cross Sections ◽

Scalp Hair ◽

The Body ◽

Equivalent Diameter ◽

Cross Sectional ◽

Hair Samples ◽

Length Width ◽

Morphological Differences

It has been demonstrated that cross sections of bundles of hair can be effectively studied using image analysis. These studies can help to elucidate morphological differences of hair from one region of the body to another. The purpose of the present investigation was to use image analysis to determine whether morphological differences could be demonstrated between male and female human Caucasian terminal scalp hair.Hair samples were taken from the back of the head from 18 caucasoid males and 13 caucasoid females (Figs. 1-2). Bundles of 50 hairs were processed for cross-sectional examination and then analyzed using Prism Image Analysis software on a Macintosh llci computer. Twenty morphological parameters of size and shape were evaluated for each hair cross-section. The size parameters evaluated were area, convex area, perimeter, convex perimeter, length, breadth, fiber length, width, equivalent diameter, and inscribed radius. The shape parameters considered were formfactor, roundness, convexity, solidity, compactness, aspect ratio, elongation, curl, and fractal dimension.

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