Wavefield Extrapolation Multiple Modeling
Prediction and attenuation of complex 3D multiples independent of acquisition geometry
Wavefield extrapolation multiple modeling (WEMM) provides a complementary approach to our surface multiple prediction methods:
- 3D GSMP general surface multiple prediction algorithm
- general deterministic water-layer demultiple
- extended internal multiple prediction
- inverse-scattering internal multiple prediction.
Convolution-based 3D surface-related multiple attenuation methods have the advantage that the multiple model is predicted from the input data with no knowledge of the subsurface. However, these methods can be challenged by complex 3D multiples, particularly for sparse seabed or towed streamer data.
WEMM uses a previously produced velocity model and migrated seismic image to compute a multiple model that can be subtracted from the input data. Thus, the process is effectively independent of acquisition geometry.
Advantages
- Attenuates multiple energy where multiples have 3D complexity
- Provides a multiple model that is independent of acquisition geometry
- Eliminates the need for data interpolation or prediction
- Improves multiple attenuation for wide-azimuth and ocean bottom cable (OBC) and ocean bottom node (OBN) systems
- Enhances multiple prediction and attenuation for long offsets
- Enhances structural imaging
Examples where multiple energy has been accurately modeled by WEMM, resulting in a clearer image.
