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dc.contributor.authorTang, Chenen_US
dc.contributor.authorMcMechan, George A.en_US
dc.date.accessioned2018-09-14T19:18:13Z
dc.date.available2018-09-14T19:18:13Z
dc.date.created2017-08-11
dc.date.issued2017-08-11en_US
dc.identifier.issn0016-8033en_US
dc.identifier.urihttp://hdl.handle.net/10735.1/6079
dc.description.abstractBecause receiver wavefields reconstructed from observed data are not as stable as synthetic source wavefields, the source-propagation vector and the reflector normal have often been used to calculate angle-domain common-image gathers (ADCIGs) from reverse time migration. However, the existing data flows have three main limitations: (1) Calculating the propagation direction only at the wavefields with maximum amplitudes ignores multiarrivals; using the crosscorrelation imaging condition at each time step can include the multiarrivals but will result in backscattering artifacts. (2) Neither amplitude picking nor Poynting-vector calculations are accurate for overlapping wavefields. (3) Calculating the reflector normal in space is not accurate for a structurally complicated reflection image, and calculating it in the wavenumber (k) domain may give Fourier truncation artifacts. We address these three limitations in an improved data flow with two steps: During imaging, we use a multidirectional Poynting vector (MPV) to calculate the propagation vectors of the source wavefield at each time step and output intermediate source-angle-domain CIGs (SACIGs). After imaging, we use an antitruncation-artifact Fourier transform (ATFT) to convert SACIGs to ADCIGs in the k-domain. To achieve the new flow, another three innovative aspects are included. In the first step, we develop an angle-tapering scheme to remove the Fourier truncation artifacts during the wave decomposition (ofMPV) while preserving the amplitudes, and we use a wavefield decomposition plus angle-filter imaging condition to remove the backscattering artifacts in the SACIGs. In the second step, we compare two algorithms to remove the Fourier truncation artifacts that are caused by the plane-wave assumption. One uses an antileakage FT (ALFT) in local windows; the other uses an antitruncation-artifact FT, which relaxes the planewave assumption and thus can be done for the global space. The second algorithm is preferred. Numerical tests indicate that this new flow (source-side MPV plus ATFT) gives high-quality ADCIGs.en_US
dc.language.isoenen_US
dc.publisherSociety of Exploration Geophysicistsen_US
dc.relation.urihttp://dx.doi.org/10.1190/GEO2016-0408.1
dc.rights©2017 Society of Exploration Geophysicistsen_US
dc.sourceGeophysics
dc.subjectBackscatteringen_US
dc.subjectMass transfer--Data processingen_US
dc.subjectElectromagnetic wavesen_US
dc.subjectFourier transformationsen_US
dc.subjectAmplitude modulationen_US
dc.subjectTime reversalen_US
dc.subjectDecomposition (Mathematics)en_US
dc.subjectVector analysisen_US
dc.titleCombining Multidirectional Source Vector with Antitruncation-Artifact Fourier Transform to Calculate Angle Gathers from Reverse Time Migration in Two Stepsen_US
dc.type.genrearticleen_US
dc.description.departmentSchool of Natural Sciences and Mathematicsen_US
dc.description.departmentCenter for Lithospheric Studiesen_US
dc.identifier.bibliographicCitationTang, C., and G. A. McMechan. 2017. "Combining multidirectional source vector with antitruncation-artifact Fourier transform to calculate angle gathers from reverse time migration in two steps." Geophysics 82(5), doi:10.1190/GEO2016-0408.1en_US
dc.identifier.volume82en_US
dc.identifier.issue5en_US
dc.contributor.utdAuthorTang, Chenen_US
dc.contributor.utdAuthorMcMechan, George A.en_US
dc.contributor.VIAF103911551 (McMechan, GA)en_US


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