Full-Waveform Inversion (FWI) derives high-resolution velocity models by minimizing the difference between observed and modeled seismic waveforms. It goes beyond refraction and reflection tomography techniques, which use only the travel time kinematics of the seismic data, by using additional information provided by the amplitude and phase of the seismic waveform.
The highly detailed models provided by FWI can be used to resolve complex geological features, as well as aid in identifying potential geohazards. These high-definition models can also be input directly to pore pressure prediction flows, time-lapse monitoring and reservoir characterization analysis. Subsurface images produced using these highly accurate models provide interpreters with a much higher degree of confidence with respect to reservoir delineation and subsequent well planning.
Many areas across the world share a common issue – complex near-surface conditions such as shallow gas anomalies, sediment carapace, permafrost, volcanic intrusions and paleo-canyons. FWI is well suited to handling these challenges."
Our latest reflection-based FWI technology allows us to resolve complex geological challenges by utilizing both refraction and reflection data. The addition of reflection information improves the velocity model beyond diving-wave penetration depths, resulting in significantly better ultra-deep images.
Many geologic environments combine multiple fracture orientations with tilted bedding, giving rise to orthorhombic symmetry. In such areas, simple polar anisotropy modeling is insufficient. Velocity models updated with orthorhombic FWI provide high-resolution details conforming to geological structure which our orthorhombic PSDM can use to deliver superior imaging of the faulting and below, solving fault shadow problems.
Find out all about TLFWI from our article in The Leading Edge, 2019:Full-waveform inversion for salt:A coming of age
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Time-lag FWI (TLFWI) is a robust approach which minimizes classic FWI cycle-skipping issues related to inaccurate starting models, amplitude mismatches and poor signal-to-noise ratio. TLFWI is proving highly successful for salt and near-salt velocity updates in challenging geological environments such as deepwater Gulf of Mexico, on both towed streamer and OBN datasets.
We revealed stunning salt model detail and subsalt imaging using TLFWI and 30 Hz TTI RTM on this Alaminos Canyon Complementary Wide Azimuth dataset, courtesy of CGG Multi-Client.
Least-Squares Migration provides images with better balanced illumination, improved signal-to-noise ratio, reduced migration artifacts and more interpretable seismic amplitudes.
CGG are leaders in the processing and imaging of every kind of ocean bottom seismic (OBS), ocean bottom node (OBN), ocean bottom cable (OBC) and permanent life-of-field (LoFS) data.
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