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GeoDepth® Seismic Traveltime Tomography is a state-of-the-art velocity model updating system designed to enhance the accuracy and resolution of different types of background velocity models that include both velocity heterogeneity and anisotropy. The GeoDepth Tomography system can efficiently handle large-scale models using different types of input data with the ability to impose different types of geological constraints.
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GeoDepth Tomography combines advanced 3D graphics with a powerful interpretation functionality for automatic picking in both post-stack and pre-stack domains. Due to its specially designed infrastructure and unique, iterative approach, GeoDepth Tomography is able to perform high-performance computing (HPC) using the Paradigm Parallel Framework (PPF), in order to solve tomography equations for anisotropic model parameters and for large-scale models.
GeoDepth Tomography supports both grid-based and model-based methods that can be used according to the problem to be solved. For example, Gulf of Mexico sediments affected by long period compaction are normally parameterized by a Cartesian grid, whereas North Sea subsurface models are usually characterized by the aging of layers using a layer-based representation. The tomography workflow also supports hybrid approaches where, for example, shallow velocity anomalies can be parameterized with grids and deeper parts with geological layers. |
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GeoDepth Tomography reduces interpretation uncertainty through a comprehensive set of input data, including wide- and multi-azimuth data, well information, and a priori geological knowledge, and by using geologically constrained solutions.
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A fully automatic process enhances efficiency and saves time by minimizing user involvement.
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New tools for automatic picking of reflection surfaces and residual moveouts on gathers enhance ease of use, efficiency and productivity.
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GeoDepth Tomography improves the strength of subsurface parameter estimation, including anisotropy.
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A powerful combination of high-performance cluster computing, rich bottom-up specular ray tracing in all azimuths and angles, automatic reflection patch picking and residual moveout picking, and anisotropic model parameter updating. These are all applied to the client’s most critical seismic assets, where project turnaround and quality are paramount.
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Storage of all information, including picks and associated attributes, such as dip, azimuth and continuity (DAC) of reflecting surfaces, surface ID, residual velocity, and others in the Pencil Database. The information can be extracted using either volume-based (ImageDAC) or reflector-based (ImagePICK) operations.
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Automatic picking of RMO at pre-defined pencil points along the pre-stack data.
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Multiple inversions to solve the tomography matrix, with different geological constraints applied independently to each geological layer or model creation of complex geology.
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Optimal operation on large computing clusters with many nodes, enabling computations involving hundreds of gigabytes for typical grid intervals of several hundred meters.
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Distributed computations over the two main tasks of tomographic matrix creation and solution.
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Integration of well information (check shots) into tomography equations for solving and controlling anisotropic inverted parameters.
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Rich set of built-in QC tools
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Velocity model determination is considered to be the most challenging process in the field of seismic data analysis. A general velocity model determination workflow consists of two main stages: Building the initial background macro velocity model, and updating the model.
The first stage consists of rough approximations, depending on the available data and the complexity and nature of the subsurface geological model. The derived model contains the long wavelength variations of the velocity field, and represents the general trend of the structural model. The second stage involves more advanced calculations, based on wave equation or ray-based methods. The goal is to update the background velocity with more detail, and achieve higher accuracy and higher resolution.
Seismic tomography is one of the main methods used to update background velocity models. The calculation is based on a linear relationship between traveltime errors along the rays travelling through the model, and subsurface velocity parameter perturbations. The background velocity model can be either isotropic (where velocity is a function of location only) or anisotropic (where velocity is a function of both location and direction).
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