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Improving data content of seismic images through high resolution acquisition and processing


IPGP - Îlot Cuvier


Séminaire de sismologie, de géosciences marines et de géophysique d'exploration

Salle 310

Risto Siliqi


Seismic technology is driven by the industry challenges: finding and understanding the reservoir. Today the expectations of seismic imaging are very high. At all stages of Exploration and Production cycle, the seismic data content should be able to provide reliable characteristic of subsurface, where resolution and illumination are the key factors. During this presentation we will highlight the importance of acquiring physical data necessary to build high resolution images. How the seismic data, acquired per any frequency bandwidth, could be transformed to a broadband pressure field and a high resolution image? Both aspects of the system, broadband reception and broadband emission will be described. The goal of this broadband acquisition system is not only to fill the notches in the spectra caused by the interference of upgoing wavefield with the echo from the see surface, but also to create real condition to acquire genuine low frequencies signal from subsurface. The low end of the spectra represents the link between reflectivity and seismic velocity and allows a new dimension of seismic images – the texture. This new data content provides the necessary constrains to Inversion for various reservoir characterization attributes and materializes fine seismic details such as channels and faults. The new acquisition technologies encompass all those challenges to lowest frequencies to the highest ones by realizing an accurate up/down separation of primary and ghost wavefields allowing deghosting, demultiple and double illumination.Increasing the frequency bandwidth is not always sufficient to achieve the best resolution in some areas. Illuminating the subsurface with a wide range of azimuth and offset is fundamental for the resolution of complex geologies. The deployment of a triple objective acquisition is necessary: full azimuth, noiseless broadband and ultra-long offset for subsalt penetration. Impressive achievements will illustrate the benefit of the resolution and illumination and especially the impact of low frequencies in imaging, velocity model building and reservoir characterization