Moveout analysis of wide-azimuth data in the presence of lateral velocity variation

Handle URI:
http://hdl.handle.net/10754/598895
Title:
Moveout analysis of wide-azimuth data in the presence of lateral velocity variation
Authors:
Takanashi, Mamoru; Tsvankin, Ilya
Abstract:
Moveout analysis of wide-azimuth reflection data seldom takes into account lateral velocity variations on the scale of spreadlength. However, velocity lenses (such as channels and reefs) in the overburden can cause significant, laterally varying errors in the moveout parameters and distortions in data interpretation. Here, we present an analytic expression for the normal-moveout (NMO) ellipse in stratified media with lateral velocity variation. The contribution of lateral heterogeneity (LH) is controlled by the second derivatives of the interval vertical traveltime with respect to the horizontal coordinates, along with the depth and thickness of the LH layer. This equation provides a quick estimate of the influence of velocity lenses and can be used to substantially mitigate the lens-induced distortions in the effective and interval NMO ellipses. To account for velocity lenses in nonhyperbolic moveout inversion of wide-azimuth data, we propose a prestack correction algorithm that involves computation of the lens-induced traveltime distortion for each recorded trace. The overburden is assumed to be composed of horizontal layers (one of which contains the lens), but the target interval can be laterally heterogeneous with dipping or curved interfaces. Synthetic tests for horizontally layered models confirm that our algorithm accurately removes lens-related azimuthally varying traveltime shifts and errors in the moveout parameters. The developed methods should increase the robustness of seismic processing of wide-azimuth surveys, especially those acquired for fracture-characterization purposes. © 2012 Society of Exploration Geophysicists.
Citation:
OCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html><head> <title>Current Links for doi: 10.1190/geo2011-0307.1 </title> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <!--geophysics.html--></head><style> body { font-size: 100%; font-family: arial, times; } #prime { padding: 5px; } #second { padding: 5px; } #links { padding: 5px; } #data { padding:5px; } #top { padding:5px; }</style><body><div id="top"> <img src="/docs/iPage/images/SEG_corp_logo.jpg" alt="SEG Corp Logo"/> <p> The Society of Exploration Geophysicists is a not-for-profit organization that promotes the science of applied geophysics and the education of geophysicists. SEG, founded in 1930, fosters the expert and ethical practice of geophysics in the exploration and development of natural resources, in characterizing the near surface, and in mitigating earth hazards. The Society, which has more than 33 000 members in 138 countries, fulfills its mission through its publications, conferences, forums, Web sites, and educational opportunities. </p> <hr/></div><div id="data"> <table width="450"> <tr><td><b>Moveout analysis of wide-azimuth data in the presence of lateral velocity variation</b></td></tr><tr><td>Takanashi,Mamoru et al.</td></tr><tr><td><i>GEOPHYSICS</i>(2012),77(3):U49</td></tr><tr><td><a href='http://dx.doi.org/10.1190/geo2011-0307.1'>http://dx.doi.org/10.1190/geo2011-0307.1</td></tr> </table> <hr/></div><div id="links"> <p> This article is available from multiple sources. <br/>Please click on the logo of the service to which you have a subscription, or click any logo to obtain pay-per-view access. </p> <div id="prime"> <a href=http://library.seg.org/doi/abs/10.1190/geo2011-0307.1><img src="/docs/iPage/images/segdl_logo.gif" alt="SEGDL Logo"/></a> </div> <div id="second"> <a href=http://geophysics.geoscienceworld.org/cgi/doi/10.1190/geo2011-0307.1><img src="/docs/iPage/images/gswbanner.gif" alt="GSW Logo"/></a> </div></div></body></html>
Publisher:
Society of Exploration Geophysicists
Journal:
GEOPHYSICS
Issue Date:
May-2012
DOI:
10.1190/geo2011-0307.1
Type:
Article
ISSN:
0016-8033; 1942-2156
Sponsors:
We are grateful to M. Al-Chalabi (Petrotech Consultancy),T. Alkhalifah (KAUST), E. Blias (VSFusion), T. Davis (CSM),V. Grechka (Marathon), E. Jenner (ION/GXT), W. Lynn (LynnInc.), and to members of the A(nisotropy)-Team of the Center forWave Phenomena (CWP) at Colorado School of Mines (CSM) forhelpful discussions. We also thank E. Jenner for providing the syntheticdata and Jeff Godwin (CWP) for assistance with the Madagascarsoftware package. This work was supported by Japan Oil, Gas andMetals National Corporation (JOGMEC) and the Consortium Projecton Seismic Inverse Methods for Complex Structures at CWP.
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Publications Acknowledging KAUST Support

Full metadata record

DC FieldValue Language
dc.contributor.authorTakanashi, Mamoruen
dc.contributor.authorTsvankin, Ilyaen
dc.date.accessioned2016-02-25T13:43:16Zen
dc.date.available2016-02-25T13:43:16Zen
dc.date.issued2012-05en
dc.identifier.citationOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html><head> <title>Current Links for doi: 10.1190/geo2011-0307.1 </title> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <!--geophysics.html--></head><style> body { font-size: 100%; font-family: arial, times; } #prime { padding: 5px; } #second { padding: 5px; } #links { padding: 5px; } #data { padding:5px; } #top { padding:5px; }</style><body><div id="top"> <img src="/docs/iPage/images/SEG_corp_logo.jpg" alt="SEG Corp Logo"/> <p> The Society of Exploration Geophysicists is a not-for-profit organization that promotes the science of applied geophysics and the education of geophysicists. SEG, founded in 1930, fosters the expert and ethical practice of geophysics in the exploration and development of natural resources, in characterizing the near surface, and in mitigating earth hazards. The Society, which has more than 33 000 members in 138 countries, fulfills its mission through its publications, conferences, forums, Web sites, and educational opportunities. </p> <hr/></div><div id="data"> <table width="450"> <tr><td><b>Moveout analysis of wide-azimuth data in the presence of lateral velocity variation</b></td></tr><tr><td>Takanashi,Mamoru et al.</td></tr><tr><td><i>GEOPHYSICS</i>(2012),77(3):U49</td></tr><tr><td><a href='http://dx.doi.org/10.1190/geo2011-0307.1'>http://dx.doi.org/10.1190/geo2011-0307.1</td></tr> </table> <hr/></div><div id="links"> <p> This article is available from multiple sources. <br/>Please click on the logo of the service to which you have a subscription, or click any logo to obtain pay-per-view access. </p> <div id="prime"> <a href=http://library.seg.org/doi/abs/10.1190/geo2011-0307.1><img src="/docs/iPage/images/segdl_logo.gif" alt="SEGDL Logo"/></a> </div> <div id="second"> <a href=http://geophysics.geoscienceworld.org/cgi/doi/10.1190/geo2011-0307.1><img src="/docs/iPage/images/gswbanner.gif" alt="GSW Logo"/></a> </div></div></body></html>en
dc.identifier.issn0016-8033en
dc.identifier.issn1942-2156en
dc.identifier.doi10.1190/geo2011-0307.1en
dc.identifier.urihttp://hdl.handle.net/10754/598895en
dc.description.abstractMoveout analysis of wide-azimuth reflection data seldom takes into account lateral velocity variations on the scale of spreadlength. However, velocity lenses (such as channels and reefs) in the overburden can cause significant, laterally varying errors in the moveout parameters and distortions in data interpretation. Here, we present an analytic expression for the normal-moveout (NMO) ellipse in stratified media with lateral velocity variation. The contribution of lateral heterogeneity (LH) is controlled by the second derivatives of the interval vertical traveltime with respect to the horizontal coordinates, along with the depth and thickness of the LH layer. This equation provides a quick estimate of the influence of velocity lenses and can be used to substantially mitigate the lens-induced distortions in the effective and interval NMO ellipses. To account for velocity lenses in nonhyperbolic moveout inversion of wide-azimuth data, we propose a prestack correction algorithm that involves computation of the lens-induced traveltime distortion for each recorded trace. The overburden is assumed to be composed of horizontal layers (one of which contains the lens), but the target interval can be laterally heterogeneous with dipping or curved interfaces. Synthetic tests for horizontally layered models confirm that our algorithm accurately removes lens-related azimuthally varying traveltime shifts and errors in the moveout parameters. The developed methods should increase the robustness of seismic processing of wide-azimuth surveys, especially those acquired for fracture-characterization purposes. © 2012 Society of Exploration Geophysicists.en
dc.description.sponsorshipWe are grateful to M. Al-Chalabi (Petrotech Consultancy),T. Alkhalifah (KAUST), E. Blias (VSFusion), T. Davis (CSM),V. Grechka (Marathon), E. Jenner (ION/GXT), W. Lynn (LynnInc.), and to members of the A(nisotropy)-Team of the Center forWave Phenomena (CWP) at Colorado School of Mines (CSM) forhelpful discussions. We also thank E. Jenner for providing the syntheticdata and Jeff Godwin (CWP) for assistance with the Madagascarsoftware package. This work was supported by Japan Oil, Gas andMetals National Corporation (JOGMEC) and the Consortium Projecton Seismic Inverse Methods for Complex Structures at CWP.en
dc.publisherSociety of Exploration Geophysicistsen
dc.subjectAnisotropyen
dc.subjectFracturesen
dc.subjectP-waveen
dc.subjectVelocity analysisen
dc.subjectWide azimuthen
dc.titleMoveout analysis of wide-azimuth data in the presence of lateral velocity variationen
dc.typeArticleen
dc.identifier.journalGEOPHYSICSen
dc.contributor.institutionColorado School of Mines, Golden, United Statesen
dc.contributor.institutionGas and Metals National Corporation, Chiba, Japanen
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