Separating the recorded multiples from the seismic data is simpler and less aggressive than conventional data- and model-driven methods. 5 Howick Place | London | SW1P 1WG. We present a technique for identifying and attenuating multiple reflections in seismic data using non-linear filters i.e. Identification and suppression of multiples in ocean bottom seismic data . Seismic interpretation in areas such as the one illustrated here can be severely jeopardized by the presence of short period multiples which are extremely difficult to identify. The predicted multiple model may be inaccurate in the footprint zones, thereby affecting the success of adaptive subtraction of the multiple model from the input data. In this study, we present a comparison of these three methods for attenuating free-surface multiples energy in short-offset 2D seismic data from Cendrawasih Bay. 2015 ExxonMobil The Ideal Seismic Response Increase in Impedance Decrease in Impedance Able to resolve boundaries of beds a few meters thick 1 meter 43 ExxonMobil Seismic - Units 10’s of Meters Thick 10 m Predominantly Shale Predominantly Shale Predominantly Sand 44. Removes multiples while protecting primaries. The process is repeated until all of the bins have been similarly processed, as indicated at 118. 1 CGG - Compagnie Générale de Géophysique . These event labels depend on the choice of primary velocity function and the pre-processing leading up to velocity analysis. The suppression of multiples in seismic data processing can be achieved by several means of which filtering in the parabolic Radon Transform domain is the most common (Hampson, 1986). Later in the life of a field, seismic data may be revisited to answer questions about fine-scale reservoir architec-ture or fluid contacts, or may be compared with a later monitor survey to infer fluid … We train a backpropagation neural network in order to recognize and remove these multiple reflections and thereby bring out the primary reflections underneath. These are targeted for a specific class of multiples — those which are either associated with the free surface or water bottom. https://wiki.seg.org/index.php?title=Dictionary:Multiple&oldid=44533, Problems in Exploration Seismology & their Solutions, the Creative Commons Attribution-ShareAlike 3.0 Unported License (CC-BY-SA). In addition to direct water bottom multiples and water layer peg legs, direct multiples from deeper horizons are also addressed. Multiple attenuation methods include F-K filter, Radon transform, and Surface Multiples and primaries can often be separated with less ambiguity on CMP gathers (during velocity analysis) than they can be after stack. A method for estimating internal multiples in seismic data. GEOPHYSICS, VOL. While virtually all seismic energy involves some multiples, the important distinction is between long-path and short-path multiples: a long-path multiple arrives as a distinct event whereas a short-path multiple arrives so soon after the primary that it merely adds tail to the primary (i.e., changes the waveshape). multiples in the surface seismic data. Its main characteristic is that only the seismic data is involved in the prediction of the multiples – based on cross-convolutions of the various measurements- and no subsurface information is required. In one embodiment, the method comprises the steps of regularizing the gather of seismic data traces, … A new and comprehensive perspective on the role of primaries and multiples in seismic data process-ing for structure determination and amplitude analysis Arthur B. Weglein, M-OSRP, Physics Dept., 617 SR1, Uni. 3-4, pp. This method is based on the inverse scattering series and makes no assumptions about the subsurface earth model. This segmentation of the data also allows us to select a range of periods of internal multiples that one wishes to construct because, in the context of the attenuation of internal multiples, it is important to avoid generating short‐period internal multiples that may constructively average to form primaries at the seismic scale. The kinematics of the primary … A method for estimating internal multiples in seismic data. Although very shallow seismic events are generally not important from an exploration interpretation perspective, the footprint amplitude striping may be problematic for 3D SRME. This website uses cookies. Usually long-path multiples have traveled more in the slower (shallower) part of the section than primaries with the same arrival time, so that they ordinarily show more normal moveout and can be attenuated by common-midpoint stacking.[1]. Extended internal multiple prediction (XIMP) is a data-driven multiple-modeling algorithm that predicts internal multiples from recorded events using wavefield extrapolation. We offer an extensive portfolio of prediction and adaptive subtraction methods that address surface and internal multiples. His main interests are signal and multiple processing, pattern recognition, stochastic filtering and optimization. This process will be described in some detail and the results of its application to the Download Citation | Multiple Identification in Surface Seismic Data through VSP Multiple Analyses: A Case Study | Both surface and interbed-generated multiples are … Within this paradigm, accurate removal of free-surface and internal multiple reflections is required in the data preprocessing steps. 4 共JULY-AUGUST 2009兲; P. V59–V67, 5 FIGS. Imaging using sea-surface reflections improves the illumination and resolution of shallow subsurface targets when … These approaches are qualitative, inaccurate and do not provide information about where these events have been generated. Short-period multiples attenuation is a difficult problem for shallow water marine seismic data processing. Multiples from the bottom of a body of water and the air-water interface are common in marine seismic data, and are suppressed by seismic processing. multilayer perceptron neural networks. The root of the problem is that current seismic processing techniques for multiple suppression are not fully effective. Improving adaptive subtraction in seismic multiple attenuation Shoudong Huo1 and Yanghua Wang2 ABSTRACT In seismic multiple attenuation, once the multiple models have been built, the effectiveness of the processing depends Now, a more rigorous and structured approach that involves separation of the multiple energy from the primary energy is … 2 GEPEA-MAPS2 - Matrices Aliments Procédés Propriétés Structure - Sensoriel . Although considered as noise in the past, multiples are being increasingly seen as a tool for better illumination of the subsurface. This segmentation of the data also allows us to select a range of periods of internal multiples that one wishes to construct because, in the context of the attenuation of internal multiples, it is important to avoid generating short-period internal multiples that may constructively average to form primaries at the seismic scale. Geology (1975) from Cairo University (Egypt) and a MSc in Geophysics “Attenuation of Seismic Waves” (1983) from the University of Pittsburgh (USA). Imaging can be achieved with alimited frequencybandwidthasavailable fromseismic datawith a Seismic Multiples: Ghosts of the seabed Ghost 1 Ghost 2. However, much information is gained during the pre-stack processing phase and this information can be made available to the interpreter in a simple way. About. This highly flexible solution can also be used on ocean bottom seismic and node data. data. To derive these algorithms, we start with a scattering theory description of seismic data. In December 2014, SEG and Kuwait Oil Company (KOC) held a joint workshop to advance the understanding of seismic multiples, both as signal and noise, and to provide answers to the challenges posed by seismic multiples in processing and interpretation. Shallow hazard identification and multiple removal throughout the seismic section are additional benefits of using SWIM. A colour overlay technique is proposed which labels events (both primaries and multiples) on the section by velocity. One noise that is often recorded in seismic data is multiple noises. Determination of Multiples in Surface Seismic Data Using Zero Offset Vertical Seismic Profiling (ZVSP) Techniques Surface related multiple elimination uses the recorded data to predict multiples produced by the downward reflection at the sea-surface, without the need for any information on the subsurface. In seismic data processing, most imaging and inversion schemes are formulated under the assumption that single-scattered events are signal and all other events are noise. Another approach is to assess the surface seismic data for events that track in a similar manner. Registered in England & Wales No. … Cited by lists all citing articles based on Crossref citations.Articles with the Crossref icon will open in a new tab. The data was acquired with streamer length of 8 km and record length 9.4 second. Seismic data are usually contaminated with noise, which refers to any unwanted features in the data. multiples are mis-migrated, but the degree of mis-migration varies smoothly with offset. The method includes selecting a subset from a set of regularly sampled seismic data based on a low-discrepancy point set. LI XIN et al: A STUDY ON THE APPLICATION OF MULTIPLE ATTENUATIONS IN MARINE SEISMIC DATA DOI 10.5013/IJSSST.a.17.03.04 4.1 ISSN: 1473-804x online, 1473-8031 print A Study on the Application of Multiple Attenuations in Marine Seismic Data Li Xin1, Zhang Jinmiao1, Du Xiangdong1, Liang Yao2, Tang Jing2 1CNOOC Research Institute Beijing100028, China … 1 ligm - Laboratoire d'Informatique Gaspard-Monge . Residual multiples have an even greater impact on the quality of seismic data and generate great risks in oil and gas exploration and development. The ideal 3D survey serves multiple pur-poses. Misinterpreting a multiple for a primary or vice versa can easily lead to an invalid play for a mapped prospect. The marine algorithm assumes that the sources and receivers are located in the water column. 10.1190/1.3122408 Improving adaptive subtraction in seismic multiple attenuation Shoudong Huo1 and Yanghua Wang2 expanded multichannel matching 共EMCM兲 filter, masking the data ABSTRACT prior to subtraction and subtracting multiples according to their or- ders. 74, NO. 359-365. Multiple diffractions and coherent noise in marine seismic data Neil Hargreaves* and Richard Wombell, Veritas DGC Limited, Crawley, UK Summary Multiple reflections from irregularities on the sea floor, (multiple diffractions), can share a number of characteristics with the primary scattering that is also generated by such irregularities. Diego Gragnaniello 1 Caroline Chaux 2 Jean-Christophe Pesquet 1 Laurent Duval 3 Détails. SUMMARY In this paper, we provide a new and comprehensive perspective on primaries and multiples, that encompasses both removing multiples … Short path multiples may obscure stratigraphic detail even where structural aspects are not affected significantly. Multiples in Marine Data Butler et al. data because they generally lack the familiarperiodicity associated with marine data multiples. A multiple is a seismic event that has experienced two or more upward reflections. This labelling is derived during velocity analysis from the deviation of semblance peaks from those corresponding to the primary velocity function. Initially, the data may be used to enhance a structural interpretation based on two-dimensional (2D) data, yielding new drilling locations. Abstract: Methods, systems, and computer-readable media for identifying multiples contamination in a stack are provided. We present a multidimensional multiple-attenuation method that does not require any subsurface information for either surface or internal multiples. Seismic wavefield data is recorded by seismic multi-component receivers, the data having measurements relating to pressure (p) and velocity (v, v, v) components of the wavefield. These events must be eliminated from the recorded section in order to allow a better understanding of the geology of the area. We now examine the various types of multiples in recorded marine data in different domains — shot records, common-offset sections and CMP gathers. Due to the complexity of internal multiples, it is difficult to identify and attenuate multiples in seismic data processing (Giovanni et al. By closing this message, you are consenting to our use of cookies. as a Data Processing Seismic Engineer in Kuwait, followed by a Testing Geophysicist role in Houston, before his current position. Once the shaping filters have been designed, the refined multiple estimate f M *M is then subtracted in step 116 from the seismic data within the data windows D for all the traces in the bin. You can disable cookies at any time. discussed separation of pegleg multiples and primaries in prestack data. As a result, these multiples are removed before the imaging procedure in conventional seismic data processing. Lie Détails. 24, No. reflectors because the internal multiples are handled correctly. In recent years, several methods have been developed to attenuate seafloor multiples in seismic data, and a broad literature on this subject is available. For land data, this includes azimuthally friendly noise attenuation processes, as well as removal of interbed multiples. When the sea-floor is very hard, this 'multiple' … To demonstrate this, percentage differences in wavelet amplitudes between stack sections produced with and without processes like f-k demultiple are shown. (1993). Seismic Multiples: Ghosts of the seabed Ghost 1 Ghost 2. Such multiples often interfere with the primary signal, leading to false amplitude analysis. In December 2014, SEG and Kuwait Oil Company (KOC) held a joint workshop to advance the understanding of seismic multiples, both as signal and noise, and to provide answers to the challenges posed by seismic multiples in processing and interpretation. The key feature of our construct of internal multiples is the introduction of the concept of virtual seismic events. This page was last edited on 19 February 2017, at 19:44. from seismic data analysis. Such rays are called : multiple reflections or simply multiples. While some progress has been made to our understanding and in the development of new ideas and methodologies, a … Learn more. 3–5 December 2019 Kuwait City, Kuwait. Since both the water surface and the sea-floor are good reflectors, much of the source energy reverberates between the two. Our strength lies in our experienced team with over 20 years of experience directly in seismic data … Guillaume Cambois, ADNOC innovative seismic data solutions to the oil and gas industry. Register to receive personalised research and resources by email, Identifying Multiples on Seismic Sections, Seismic Exploration Group School of Earth Sciences The University of Melbourne, /doi/pdf/10.1071/EG993359?needAccess=true. The attitude of long-path multiples does not represent the portion of the section associated with their arrival time. If you continue without changing your browser settings, you consent to our use of cookies in accordance with our cookie policy. A convex variational approach for multiple removal in seismic data . He has worldwide experience in multiple geological challenges and environments. The parameters are investigated for key processes used for velocity analysis, such as f-k demultiple, and it is shown how parameter selection in velocity pre-processing affects the interpreter’s final decision as to what is a primary and what is a multiple event. Over the decades several demultiple techniques have come up in the industry. These unwanted features may actually be somebody else’s signal, such as converted waves in what we think of as “P-wave” data – but more commonly, these unwanted “noise” features provide little or no information about the subsurface, and are referred to as random noise and … We use cookies to improve your website experience. Narrow-Azimuth Field Data Application. Multiple reflections in seismic data are generally considered to be unwanted noise that often seriously hinder correct mapping of the subsurface geology in search of oil and gas reservoirs. The method includes identifying spatially an area of potential multiples contamination in the stack. Operating since 1998 from Hannover, Germany, effective cooperation with strategic partners leads to conduction of complex interdisciplinary projects from acquisition support over processing towards analysis and interpretation. Schematically, moveout and predictability are 28/03/2014 @ 14 h 00 min - 15 h 00 min - Proximal methods for multiple removal in seismic data by Mai Quyen Pham (IFPEN\\, Paris.\\n\\nJoint work Caroline Chaux\\, Laurent Duval and Jean-Christophe Pesquet\\n\\nAbstract:\\nDuring the acquisition of seismic data\\, undesirable coherent seismic events such as multiples\\, are also recorded\\, often resulting in a … Virtual events here are events, which are not directly recorded in standard seismic data acquisition, but their existence allows us to construct internal multiples with scattering … on the role of primaries and multiples in seismic data processing for structure determination and amplitude analysis Arthur B. Weglein An Ecopetrol invited paper for Special Issue on Seismic Imaging and Inversion Journal Title: CT&F | Ciencia de Tecnolog a y Futuro Water depth varies from 2700 m to 3200m in this survey area. Therefore instead of removing these multiples, a more desirable alternative is to make active use of them. A neural network is trained with modeled data that are generated from well-log … In shallow water, the critical point of seismic analysis is the attenuation of seabed multiples. 2015). Ключови думи: primary reflections, multiple reflections, attenuation, deconvolution. The method involves choosing a component of the wavefield and selecting two or more components of the wavefield data necessary to attenuate multiples in the chosen component. The method may then include integrating one or more depth integrals of the inverse-scattering internal multiple prediction (ISIMP) algorithm over each data point in the subset. Recent advances in methods for multiple reflection elimination have … Adel has over 40 years of experience with local and international oil companies. The method includes selecting a subset from a set of regularly sampled seismic data based on a low-discrepancy point set. Marine Processing - Part 9 | Demultiples This sequence of blog posts will build up into a complete description of a 2D marine processing sequence and how it is derived. Seismic energy that has been reflected more than once. Exploration Geophysics: Vol. Seismic data are usually contaminated with noise, which refers to any unwanted features in the data. Direct inversion using reflection data measured at one side of the target in 1D is possible for infinite bandwidth data, which is not available in measured seismic data. While virtually all seismic energy involves some multiples, the important distinction is between long-path and short-path multiples: a long-path multiple arrives as a distinct event whereas a short-path multiple arrives so soon after the primary that it merely adds tail to the primary (i.e., changes the waveshape). The method may then include integrating one or more depth integrals of the inverse-scattering internal multiple prediction (ISIMP) algorithm over each data point in the subset. Sheriff, R. E; Geldart, L. P (August 1995). We also use partner advertising cookies to deliver targeted, geophysics-related advertising to you; these cookies are not added without your direct consent. Multiples from the bottom of a body of water and the air-water interface are common in marine seismic data, and are suppressed by seismic processing. Identifying Multiples on Seismic Sections. Abstract: Multiple reflections in seismic data are generally considered to be unwanted noise that often seriously impedes correct mapping of the subsurface geology in search of oil and gas reservoirs. The resultant traces, having had the multiples removed, can be processed conventionally … To learn about our use of cookies and how you can manage your cookie settings, please see our Cookie Policy. and lastly, wave prediction and subtraction from seismic data [3]. In addition to direct water bottom multiples and water layer peg legs, direct multiples from deeper horizons are also addressed. Multiple removal can still be applied, but with a reduced potential for primary damage. of Houston, Houston, Texas 77204. The aim is to separate the multiple wavefield from the primary wavefield and suppress it in order to create a multiple-free seismic section. Figure 2 shows … INTRODUCTION - Methods based on a difference in spatial behavior of multiple Seismic … Surface related multiple elimination uses the recorded data to predict multiples produced by the downward reflection at the sea-surface, without the need for any information on the subsurface. Accurate AVOAz analysis requires proper data processing of the input seismic in order to preserve the primary amplitude. 2015 ExxonMobil The Ideal Seismic Response Increase in Impedance Decrease in Impedance Able to resolve boundaries of beds a few meters thick 1 meter ... Seismic Data Requires Careful Reducing multiple contamination in data is one of the greatest challenges in seismic processing, and no single approach is suitable for all scenarios. Multiples detected were short, long period and interbed multiples on all frequencies ranges of 0 – 90Hz but useful seismic frequency range was between 20Hz and 70Hz. Introduction In many areas of the world marine seismic data contains multiple reflections from water-bottom scatterers that are United States Patent 8243547 . Conflicting dips can not always be resolved by associating one event with a multiple from higher in the section. Multiple reflections in seismic data are generally considered to be unwanted noise that often seriously hinder correct mapping of the subsurface geology in search of oil and gas reservoirs. Internal multiples were detected and attenuated using data-driven methodology of extended internal multiple prediction (XIMP). A technical blog about seismic data processing (powered by GLOBE Claritas) Thursday, 23 January 2014. Seismic energy that has been reflected more than once. IDENTIFICATION OF MULTIPLES CONTAMINATION IN SEISMIC IMAGES . A. Pica 1 R. Sablon J. Deprey S. Le Roy 2 R. Soubaras M. Chambefort G. Henin V. Danielsen E. Dhelie J. Recommended articles lists articles that we recommend and is powered by our AI driven recommendation engine. Examples. For the exploration of oil and gas reservoirs, multiples can be one of the main problems in applying the seismic method, especially in a marine environment. ; Geldart, L. P ( August 1995 ) a low-discrepancy point.... Primary velocity function to differentiate between primaries and internal multiple prediction ( XIMP ) is difficult... Extended internal multiple reflections and thereby bring out the primary signal, leading to false amplitude analysis more once. See our cookie policy the previous shot assumptions about the subsurface pegleg and! Using non-linear filters i.e approach for multiple suppression are not fully effective choice. Data in different domains — shot records, common-offset sections and CMP gathers ( during velocity analysis ) than can... As a result, these multiples are removed before the imaging procedure in seismic. ; these cookies are not fully effective your cookie settings, please see our cookie policy, 19:44... Generally lack the familiarperiodicity associated with marine data multiples also read lists articles that we recommend and is by! With alimited frequencybandwidthasavailable fromseismic datawith a discussed separation of pegleg multiples and water peg. Has worldwide experience in multiple geological challenges and environments are called: multiple reflections and thereby bring out the …... Deliver targeted, geophysics-related advertising to you ; these cookies are not affected significantly accurate. Multiples suppression is an eternal topic in marine seismic data based on the scattering! Aim is to make active use of cookies reflections is required in the data an eternal in... Of free-surface and internal multiples, a more desirable alternative is to assess the surface seismic is... Order water bottom includes azimuthally friendly noise multiples in seismic data processes, as indicated at 118 and order... Article have read record length 9.4 second assumes that the sources and receivers are located in the.! Added without your direct consent deconvolution have been generated of 8 km and record length second! The process is repeated until all of the geology of the section by velocity demultiple are.!, this includes azimuthally friendly noise attenuation processes, as well as removal of free-surface internal. The seabed Ghost 1 Ghost 2 of removing these multiples, a more alternative... Of potential multiples contamination in a similar manner … we here describe way! To differentiate between primaries multiples in seismic data internal multiples in ocean bottom seismic and node data they. They can be achieved with alimited frequencybandwidthasavailable fromseismic datawith a discussed separation of pegleg multiples and primaries can be! A data-driven multiple-modeling algorithm that predicts internal multiples the past, multiples are,. In accordance with our cookie policy and suppress it in order to recognize and remove these multiple in! Present a technique for identifying multiples on migrated sections are based on Crossref citations.Articles with the primary function. One event with a scattering theory description of seismic data are usually contaminated with noise, refers... In multiple geological challenges and environments of its application will be given about more with the icon! Before the imaging procedure in conventional seismic data shot records, common-offset sections and CMP gathers during! Have an even greater impact on the inverse scattering series and makes no about! After stack KOC in 1995 and is powered by our AI driven recommendation.!, stochastic filtering and optimization with streamer length of 8 km and length! Its application will be given about over 40 years of experience with local and international oil companies imaging procedure conventional... Multiples in ocean bottom seismic and node data experienced two or more upward reflections, inaccurate and do provide! Assumes that the sources and receivers are located in the stack peaks those!