Improving atlantis TTI model building: OBN+NATS, prism waves &amp; 3D RTM angle gathers

Roberts, Mark; Dy, Timmy; Ji, Shuai; Reasnor, Micah; Shepherd, David

doi:10.1190/1.3627868

Cited by 14 publications

(2 citation statements)

References 7 publications

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“…Like many subsalt fields in the GoM, seismic imaging at Atlantis is very challenging due to complex salt structures in the overburden (Figure 1). Recently, great efforts were made to obtain a better tilted transverse isotropic (TTI) velocity model for the Atlantis field using multi-wide azimuth and ocean-bottom node (OBN) data (Roberts et al, 2011;Shen et al, 2017). Yet 3D vertical seismic profile (VSP) surveys may offer even better opportunities to obtain high-quality images near the wellbore compared to surface steamer and OBN data due to the fact that the wave propagation is less distorted by salt since the receivers are generally placed below the salt.…”

Section: Introductionmentioning

confidence: 99%

3D VSP imaging under a complex salt finger at Atlantis, Gulf of Mexico

Lee

Yang

Chrisman³

et al. 2018

SEG Technical Program Expanded Abstracts 2018

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To improve image resolution in the vicinity of the well, 3D vertical seismic profile (VSP) data was acquired at the Atlantis field in the Gulf of Mexico (GoM) to complement the existing towed-streamer and ocean-bottom node (OBN) data. Two unique data challenges require special consideration and innovative techniques in order to unlock the full imaging potential at the Atlantis field: (1) illumination issues related to the receivers being placed in a well that goes through a complicated salt finger; (2) receiver reorientation issues related to the survey's twophase acquisition due to receivers being pulled out and placed back into the well. We demonstrate how we mitigate the impact of these challenges through improved XYZ vector fidelity reorientation and least-squares reverse time migration (LSRTM).

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Section: Introductionmentioning

confidence: 99%

3D VSP imaging under a complex salt finger at Atlantis, Gulf of Mexico

Lee

Yang

Chrisman³

et al. 2018

SEG Technical Program Expanded Abstracts 2018

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“…Another application of RTM 3D dip gathers of point diffractors is in subsalt illumination compensation and noise attenuation. Although wide azimuth and full azimuth acquisitions (Michell et al, 2006;Roberts et al, 2011;Tim, 2011), together with advances in RTM (Zhang et al, 2007;Zhang and Zhang, 2009), have brought significant advancements in subsalt imaging in the GOM, we continue to see poor subsalt images of weak illumination in the presence of complex salt structures (Gherasim et al, 2010;Shen et al, 2011;. Starting with a reflectivity model M and a velocity model, a field acquisition acquiring seismic data D can be simulated with a forward modeling operator F in the form of…”

Section: Introductionmentioning

confidence: 99%

Subsalt illumination analysis using RTM 3D dip gathers

Tang

2012

SEG Technical Program Expanded Abstracts 2012

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Reverse Time Migration (RTM) is now the preferred option for subsalt imaging in deep water Gulf of Mexico, and its 3D angle gather output plays an important role in subsalt velocity updating and illumination compensation. We now present recently-developed RTM 3D dip gathers, which are common-image gathers (CIGs) generated through wavefield decomposition and grouped into the subsurface dip-azimuth angle domain. RTM 3D dip gathers offer an opportunity for subsalt illumination analysis. We propose to use sparsely-distributed density point diffractors in the subsalt region for illumination analysis via a modelingmigration procedure. A density model with point diffractors is used for forward modeling, followed by RTM with 3D dip gather output to determine the variable illumination coverage for all subsalt dip and azimuth angles, which can be used for acquisition design, e.g., in deciding the maximum offset. Furthermore, illumination scalars derived from the diffractor-based dip gathers are applied to RTM 3D dip gathers of real data to improve the signal-to-noise ratio (S/N) and compensate for dip-dependent illumination. Because no preconceived information about the subsalt structures is involved, this illumination compensation scheme is not interpretation-driven, resulting in enhanced subsalt images that are not biased towards interpretation preferences. We validate the workflow on a real wide azimuth dataset in the Gulf of Mexico.

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Reflection Angle-Domain Pseudoextended Least-Squares Reverse Time Migration Using Hybrid Regularization

Gao

et al. 2021

IEEE Trans. Geosci. Remote Sensing

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Improving atlantis TTI model building: OBN+NATS, prism waves & 3D RTM angle gathers

Cited by 14 publications

References 7 publications

3D VSP imaging under a complex salt finger at Atlantis, Gulf of Mexico

3D VSP imaging under a complex salt finger at Atlantis, Gulf of Mexico

Subsalt illumination analysis using RTM 3D dip gathers

Reflection Angle-Domain Pseudoextended Least-Squares Reverse Time Migration Using Hybrid Regularization

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