3D finite‐offset tomographic inversion of CRP‐scan data, with or without anisotropy

Guillaume, P.; Audebert, F.; David, B.; Herrenschmidt, Ariane; Zhang, Xiaoming; Berthet, Philippe

doi:10.1190/1.1816731

Cited by 37 publications

(20 citation statements)

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“…The possibility to use kinematic information from PreSTM gathers to derive a depth velocity model comes from the use of "kinematic" invariant described in Guillaume et al, (2001). Consider a locally coherent event in a common offset depth migrated image ( Figure 1).…”

Section: Depth Velocity Model Building From Prestm Gathersmentioning

confidence: 99%

“…The kinematic invariant can be used directly as input data for depth velocity model building by tomographic inversion (Guillaume et al, 2001), with the potential benefit of a single picking step. A "standard" depth imaging workflow based on kinematic invariants can then be proposed with the following steps:…”

Section: Figure 1: Computation Of Kinematic Invariants By Kinematic Dmentioning

confidence: 99%

“…In Lambaré et al (2007), we proposed a fast and accurate workflow to allow us to take full advantage of a previous time migrated dataset to derive a depth migration velocity model. This approach mimics our "standard" depth imaging workflow (Guillaume et al, 2001(Guillaume et al, , 2004 except that the dense volumetric dip and Residual MoveOut (RMO) automated picking is done on Pre-Stack Time Migration (PreSTM) gathers rather than on Pre-Stack Depth Migration (PreSDM) gathers. The benefits are to bypass the initial PreSDM required for the picking and to make use of the quality of the focusing of the PreSTM for the automated picking with no compromise on the accuracy.…”

Section: Introductionmentioning

confidence: 99%

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Deriving a Depth Velocity Model Using Time Migrated Data – Case Study

Wolfarth¹,

Capar²,

Lambaré³

et al. 2007

69th EAGE Conference and Exhibition Incorporating SPE EUROPEC 2007

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We present the application to a real dataset of a fast and accurate workflow for time to depth conversion. It allows taking full advantage of an existing time imaging project for leading a depth imaging project. We present here the various steps involved in the imaging sequence. It is based on a dense volumetric dip and residual move-out picking in the prestack time migrated domain. This kinematic information is then demigrated to compute multi-offset un-migrated attributes -called seismic invariants -used as input data for a multi-offset tomographic inversion. Finally the resulting depth velocity model is used for prestack depth migration. Our application to the real dataset demonstrates that accurate results can be obtained with a fast turnaround time.

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Section: Depth Velocity Model Building From Prestm Gathersmentioning

confidence: 99%

Section: Figure 1: Computation Of Kinematic Invariants By Kinematic Dmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Deriving a Depth Velocity Model Using Time Migrated Data – Case Study

Wolfarth¹,

Capar²,

Lambaré³

et al. 2007

69th EAGE Conference and Exhibition Incorporating SPE EUROPEC 2007

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“…Nevertheless, most velocity model building is still performed using Kirchhoff migration combined with ray-based, finite-offset tomography (Wang et al, 1995;Zhou et al, 2001Zhou et al, , 2003; (Guillaume et al, 2001(Guillaume et al, , 2003. Combining wave-equation migration with ray-based tomography still represents a challenge because of their different methods for simulating wave propagation in complex velocity media.…”

Section: Introductionmentioning

confidence: 99%

A 3D subsalt tomography based on wave-equation migration-perturbation scans

Wang¹,

Dirks²,

Guillaume

et al. 2006

GEOPHYSICS

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We have developed a simple but practical methodology for updating subsalt velocities using wave-equation, migration-perturbation scans. For the sake of economy and scalability (with respect to full source-receiver migration) and accuracy (with respect to common-azimuth migration), we use shot-profile, wave-equation migration. As input for subsalt-velocity analysis, we provide waveequation migration scans with velocity scanning limited to the subsalt sediments. Throughout the migration-scan sections, we look for the best focusing or structural positioning of characteristic seismic events. The picking on the migration stacks selects the value of the best perturbation attribute (alpha-scaling factor) along with the corresponding position and local dip for the chosen seismic events. The associated, locally coherent events are then demigrated to the base of the salt horizon. Our key observation is that this process is theoretically equivalent to performing a datuming to a base of salt followed by subsalt migration of the redatumed data perturbed-velocity profiles. Thanks to this implicit redatuming of shot profiles, no ray tracing through the salt body is required. Thus, the events picked on the subsalt-velocity scans only need to be demigrated to the base of salt. For the event demigration we use 3D specularray tracing up to the base of the salt horizon within a predefined range of reflection angles. Event demigration produces model-independent data -time and time slope -that are then kinematically migrated using the current tomographic-inversion working model. To find a finalvelocity model that will flatten best the remigrated events on common image point (CIP) angle gathers, we use the same set of demigrated observation data as the input data set for several nonlinear iterations of 3D tomographic inversion.

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“…Unfortunately it has become widely accepted that simple but fast vertical velocity update techniques such as the one proposed by Deregowski (1990) fail in the presence of complex geological structures. The use of more accurate but a more computation intensive tomographic inversion schemes offers a solution (Guillaume et al 2001, Sexton et al 2001.…”

Section: Introductionmentioning

confidence: 99%

3D finite‐offset depth tomography model building: Green Canyon, Gulf of Mexico

Guillaume¹,

Chazalnoel²,

Talaalout³

et al. 2003

SEG Technical Program Expanded Abstracts 2003

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A more detailed velocity analysis is required for successful pre-stack depth migration model building and tomographic methods offer a potential solution. However, migration velocity analysis is often a underdetermined problem. We present a new finite-offset depth tomography scheme that overcomes the problems of non-linearity and allows us to perform automatic dense velocity analysis in structurally complex areas were classical linear methods fail. We demonstrate the advantage of the new tomography scheme on a deep offshore Gulf of Mexico dataset from the Green Canyon area.

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3D finite‐offset tomographic inversion of CRP‐scan data, with or without anisotropy

Cited by 37 publications

References 0 publications

Deriving a Depth Velocity Model Using Time Migrated Data – Case Study

Deriving a Depth Velocity Model Using Time Migrated Data – Case Study

A 3D subsalt tomography based on wave-equation migration-perturbation scans

3D finite‐offset depth tomography model building: Green Canyon, Gulf of Mexico

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