Investigation of deep-water Gulf of Mexico subsalt imaging using anisotropic model, data set and RTM — Tempest

Geophysics ◽  
2011 ◽  
Vol 76 (5) ◽  
pp. WB21-WB26 ◽  
Author(s):  
Fatmir Hoxha ◽  
Jacqueline O’Connor ◽  
Jeff Codd ◽  
David Kessler ◽  
Alex Bridge ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Deep Water ◽  
Model Building ◽  
Earth Model ◽  
Anisotropic Model ◽  
Model Data ◽  
Data Set ◽  
Depth Imaging ◽  
The Tempest ◽  
Time Migration

Performing accurate depth-imaging is an essential part of deep-water Gulf of Mexico exploration and development. Over the years, depth-imaging technology has provided reliable seismic images below complicated salt bodies, and has been implemented in workflows for both prospect generation as well as reservoir development. These workflows include time domain preprocessing using various multiple elimination techniques, anisotropic model building, and depth-imaging using anisotropic reverse time migration (RTM). However, the accuracy of the depth-migrated volumes is basically unknown because they are tested only in the locations where a well is drilled. In order to learn about the accuracy of anisotropic deep water Gulf of Mexico model building, and depth-imaging tools which are used for processing and imaging of field acquired data, we created a 3D vertical transverse isotropic (VTI) anisotropic earth model and a 3D seismic data set representing subsalt Gulf of Mexico geology. The model and data set are referred to as the Tempest data set, the original being created several years ago. The recent model and data set were created incorporating upgraded technology to reflect recent developments in data acquisition, model building and depth-imaging. Our paper presents the new Tempest anisotropic model, data set, and RTM prestack depth-migration (PSDM) results. The Tempest RTM PSDM is being used to learn about the differences between the exact geological model and the RTM PSDM image, helping in the interpretation of real RTM prestack depth-migrated data.

Enhanced anisotropic model building methodology and pre‐stack depth imaging in deep water Gulf of Mexico: A case history

2008 ◽  
Author(s):  
Wilfred Whiteside ◽  
Wenlong Xu ◽  
Zhiming Li ◽  
Ashley Lundy ◽  
Itze Chang
Keyword(s):  
Gulf Of Mexico ◽  
Deep Water ◽  
Case History ◽  
Model Building ◽  
Anisotropic Model ◽  
Depth Imaging

Anisotropic model building in complex media: Comparing three successful strategies in deep water Gulf of Mexico

2011 ◽  
Author(s):  
Olga Zdraveva ◽  
Michael Cogan ◽  
Robert Hubbard ◽  
Michael O'Briain ◽  
David Watts
Keyword(s):  
Gulf Of Mexico ◽  
Deep Water ◽  
Model Building ◽  
Anisotropic Model ◽  
Complex Media

Enhanced prestack depth imaging of wide-azimuth data from the Gulf of Mexico: A case history

Geophysics ◽  
2011 ◽  
Vol 76 (5) ◽  
pp. WB79-WB86 ◽  
Author(s):  
Xuening Ma ◽  
Bin Wang ◽  
Cristina Reta-Tang ◽  
Wilfred Whiteside ◽  
Zhiming Li
Keyword(s):  
Image Quality ◽  
Gulf Of Mexico ◽  
Large Scale ◽  
Velocity Model ◽  
Reverse Time ◽  
Reverse Time Migration ◽  
Delayed Imaging ◽  
Data Set ◽  
Depth Imaging ◽  
Time Migration

We present a case study of enhanced imaging of wide-azimuth data from the Gulf of Mexico utilizing recent technologies; and we discuss the resulting improvements in image quality, especially in subsalt areas, relative to previous results. The input seismic data sets are taken from many large-scale wide-azimuth surveys and conventional narrow-azimuth surveys located in the Mississippi Canyon and Atwater Valley areas. In the course of developing the enhanced wide azimuth processing flow, the following three key steps are found to have the most impact on improving subsalt imaging: (1) 3D true azimuth surface-related multiple elimination (SRME) to remove multiple energy, in particular, complex multiples beneath salt; (2) reverse-time migration (RTM) based delayed imaging time (DIT) scans to update the complex subsalt velocity model; and (3) tilted transverse isotropic (TTI) RTM to improve image quality. Our research focuses on the depth imaging aspects of the project, with particular emphasis on the application of the DIT scanning technique. The DIT-scan technique further improves the accuracy of the subsalt velocity model after conventional ray-based subsalt tomography has been performed. We also demonstrate the uplift obtained by acquiring a wide-azimuth data set relative to a standard narrow-azimuth data set, and how orthogonal wide-azimuth is able to enhance the subsalt illumination.

Evaluating the accuracy of deep water Gulf of Mexico depth imaging — The Tempest results

2008 ◽  
Author(s):  
Richard Brietzke ◽  
Alex Bridge ◽  
Dana Jurick ◽  
Adam Seitchik
Keyword(s):  
Gulf Of Mexico ◽  
Deep Water ◽  
Depth Imaging ◽  
The Tempest

Use of RTM full 3D subsurface angle gathers for subsalt velocity update and image optimization: Case study at Shenzi field

Geophysics ◽  
2011 ◽  
Vol 76 (5) ◽  
pp. WB27-WB39 ◽  
Author(s):  
Zheng-Zheng Zhou ◽  
Michael Howard ◽  
Cheryl Mifflin
Keyword(s):  
Model Building ◽  
Transverse Isotropy ◽  
Velocity Model ◽  
Reverse Time ◽  
Reverse Time Migration ◽  
Data Set ◽  
Edge Diffraction ◽  
Time Migration ◽  
Image Optimization ◽  
Free Generation

Various reverse time migration (RTM) angle gather generation techniques have been developed to address poor subsalt data quality and multiarrival induced problems in gathers from Kirchhoff migration. But these techniques introduce new problems, such as inaccuracies in 2D subsurface angle gathers and edge diffraction artifacts in 3D subsurface angle gathers. The unique rich-azimuth data set acquired over the Shenzi field in the Gulf of Mexico enabled the generally artifact-free generation of 3D subsurface angle gathers. Using this data set, we carried out suprasalt tomography and salt model building steps and then produced 3D angle gathers to update the subsalt velocity. We used tilted transverse isotropy RTM with extended image condition to generate full 3D subsurface offset domain common image gathers, which were subsequently converted to 3D angle gathers. The angle gathers were substacked along the subsurface azimuth axis into azimuth sectors. Residual moveout analysis was carried out, and ray-based tomography was used to update velocities. The updated velocity model resulted in improved imaging of the subsalt section. We also applied residual moveout and selective stacking to 3D angle gathers from the final migration to produce an optimized stack image.

Integrated earth model building in the shallow water Bay of Campeche in the Gulf of Mexico

2021 ◽  
Author(s):  
Nadxieli De La Rosa Perez ◽  
Juan Perdomo ◽  
David Manzano ◽  
Hao Deng ◽  
Anastasia Pavlovskaya ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Shallow Water ◽  
Model Building ◽  
Earth Model

3D seismic imaging of volcanogenic massive sulfide deposits in the Flin Flon mining camp, Canada: Part 2 — Forward modeling

Geophysics ◽  
2012 ◽  
Vol 77 (5) ◽  
pp. WC81-WC93 ◽  
Author(s):  
Michal Malinowski ◽  
Ernst Schetselaar ◽  
Donald J. White
Keyword(s):  
Synthetic Data ◽  
Massive Sulfide ◽  
Ore Deposits ◽  
Earth Model ◽  
Seismic Modeling ◽  
Volcanogenic Massive Sulfide ◽  
Data Set ◽  
Rock Interaction ◽  
Time Migration ◽  
Flin Flon

We applied seismic modeling for a detailed 3D geologic model of the Flin Flon mining camp (Canada) to address some imaging and interpretation issues related to a [Formula: see text] 3D survey acquired in the camp and described in a complementary paper (part 1). A 3D geologic volumetric model of the camp was created based on a compilation of geologic data constraints from drillholes, surface geologic mapping, interpretation of 2D seismic profiles, and 3D surface and grid geostatistical modeling techniques. The 3D modeling methodology was based on a hierarchical approach to account for the heterogeneous spatial distribution of geologic constraints. Elastic parameters were assigned within the model based on core sample measurements and correlation with the different lithologies. The phase-screen algorithm used for seismic modeling was validated against analytic and finite-difference solutions to ensure that it provided accurate amplitude-variation-with-offset behavior for dipping strata. Synthetic data were generated to form zero-offset (stack) volume and also a complete prestack data set using the geometry of the real 3D survey. We found that the ability to detect a clear signature of the volcanogenic massive sulfide with ore deposits is dependent on the mineralization type (pyrite versus pyrrhotite rich ore), especially when ore-host rock interaction is considered. In the presence of an increasing fraction of the host rhyolite rock within the model volume, the response from the lower impedance pyrrhotite ore is masked by that of the rhyolite. Migration tests showed that poststack migration effectively enhances noisy 3D DMO data and provides comparable results to more computationally expensive prestack time migration. Amplitude anomalies identified in the original 3D data, which were not predicted by our modeling, could represent potential exploration targets in an undeveloped part of the camp, assuming that our a priori earth model is sufficiently accurate.

3-D prestack Kirchhoff depth migration: From prototype to production in a massively parallel processor environment

Geophysics ◽  
1998 ◽  
Vol 63 (2) ◽  
pp. 546-556 ◽  
Author(s):  
Herman Chang ◽  
John P. VanDyke ◽  
Marcelo Solano ◽  
George A. McMechan ◽  
Duryodhan Epili
Keyword(s):  
Model Building ◽  
Velocity Model ◽  
Production Scale ◽  
Data Set ◽  
Depth Migration ◽  
Prestack Migration ◽  
Prototype Development ◽  
Time Migration ◽  
Intel Paragon ◽  
Kirchhoff Depth Migration

Portable, production‐scale 3-D prestack Kirchhoff depth migration software capable of full‐volume imaging has been successfully implemented and applied to a six‐million trace (46.9 Gbyte) marine data set from a salt/subsalt play in the Gulf of Mexico. Velocity model building and updates use an image‐driven strategy and were performed in a Sun Sparc environment. Images obtained by 3-D prestack migration after three velocity iterations are substantially better focused and reveal drilling targets that were not visible in images obtained from conventional 3-D poststack time migration. Amplitudes are well preserved, so anomalies associated with known reservoirs conform to the petrophysical predictions. Prototype development was on an 8-node Intel iPSC860 computer; the production version was run on an 1824-node Intel Paragon computer. The code has been successfully ported to CRAY (T3D) and Unix workstation (PVM) environments.

Application of multiparameter full-waveform inversion in Central Luconia Basin, Sarawak

2016 ◽  
Vol 4 (4) ◽  
pp. SU17-SU24 ◽  
Author(s):  
Vanessa Goh ◽  
Kjetil Halleland ◽  
René-Édouard Plessix ◽  
Alexandre Stopin
Keyword(s):  
Model Building ◽  
Waveform Inversion ◽  
Velocity Model ◽  
Thin Layers ◽  
Earth Model ◽  
Full Waveform Inversion ◽  
Data Set ◽  
Full Waveform ◽  
Velocity Variations ◽  
Central Luconia

Reducing velocity inaccuracy in complex settings is of paramount importance for limiting structural uncertainties, therefore helping the geologic interpretation and reservoir characterization. Shallow velocity variations due, for instance, to gas accumulations or carbonate reefs, are a common issue offshore Malaysia. These velocity variations are difficult to image through standard reflection-based velocity model building. We have applied full-waveform inversion (FWI) to better characterize the upper part of the earth model for a shallow-water field, located in the Central Luconia Basin offshore Sarawak. We have inverted a narrow-azimuth data set with a maximum inline offset of 4.4 km. Thanks to dedicated broadband preprocessing of the data set, we could enhance the signal-to-noise ratio in the 2.5–10 Hz frequency band. We then applied a multiparameter FWI to estimate the background normal moveout velocity and the [Formula: see text]-parameter. Full-waveform inversion together with broadband data processing has helped to better define the faults and resolve the thin layers in the shallow clastic section. The improvements in the velocity model brought by FWI lead to an improved image of the structural closure and flanks. Moreover, the increased velocity resolution helps in distinguishing between two different geologic interpretations.

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