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Collaborating Authors
Results
Complex Depth Imaging Using Reverse Time Migration for an Integrated High-Density Point-Source and Receiver Survey Onshore U.A.E. – A Case Study
Zubay, Erick (WesternGeco) | Cunnell, Chris (WesternGeco) | Zarkhidze, Alexander (WesternGeco) | Baioumy, Mohamed (WesternGeco) | Herrera, Luis Viertel (Crescent Petroleum) | Al Qadi, Abdulla (Crescent Petroleum)
Summary We present the results of an integrated acquisition, processing and imaging survey in an area of complex near surface and thrust belt geology onshore Sharjah, UAE. High productivity point-source point-receiver data with full azimuth geometry was acquired. Steep dips and strong velocity heterogeneity cause complex wave propagation, and require advanced prestack depth migration (PSDM) to resolve. Key elements of the PSDM workflow are outlined, with an emphasis on those stages closely linked to the advantages of the full azimuth long offset acquisition geometry. The results of the final TTI Reverse Time Migration (RTM) depth images show the expected improvement over time-domain equivalents. Accurate velocity model building remains the key challenge, and requires a combination of data conditioning, careful interpretative input, and a velocity updating methodology that takes full advantage of the rich azimuth acquisition geometry.
Near-Surface Characterization, Challenges, and Solutions for High-Density, High-Productivity, Broadband Vibroseis Point-Source and Receiver Survey – A Case Study
Zarkhidze, Alexander (WesternGeco) | Strobbia, Claudio (WesternGeco) | Ibrahim, Abdallah (WesternGeco) | Herrera, Luis Viertel (Crescent Petroleum Sharjah) | Al Qadi, Abdulla (Crescent Petroleum Sharjah) | Leeds, Alan (_)
Summary We present the results of the near-surface characterization for a 3D survey in thrust belt area in Sharjah, United Arab Emirates. The near surface is very complex, with steeply dipping layers, faults, extreme lateral and vertical velocity variations, and vertical velocity inversions: all these features challenge conventional, refraction-based seismic methods. Surface-wave analysis and inversion provide a geologically consistent near-surface velocity model. Integration and validation of the model using other near-surface data, such as analysis of refractions and upholes, is presented along with a workflow for integrating near-surface measurements and statics computation. The shallow earth model, besides being used for the near-surface perturbation corrections, is interpreted together with other measurements. We show that the near-surface complexity is not only a cause of distortions and perturbations in the deep seismic images. The near-surface characterization can provide geologically consistent models, with high spatial resolution to identify structural and lithological elements of the near surface, which can be used for geological modeling and in general exploration.
- Asia > Middle East > UAE > Sharjah Emirate > Sharjah (0.25)
- North America > Canada > Alberta > Woodlands County (0.24)
- Geology > Rock Type (0.68)
- Geology > Structural Geology > Tectonics > Compressional Tectonics > Fold and Thrust Belt (0.35)
- Geophysics > Seismic Surveying > Seismic Processing (1.00)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling > Seismic Inversion (0.69)