The Broadest Bandwidths Onshore and Offshore
The importance of recording the full range of frequencies (low as well as high) is widely accepted for high-resolution imaging. High fidelity, low frequency data provide deeper penetration for the clear imaging of deep targets, as well as providing greater stability in inversion.
Broader bandwidths produce sharper wavelets without sidelobes to provide high-resolution imaging of important shallow features such as thin beds and small sedimentary traps.
The lack of sidelobes provided by the low frequencies in a broadband wavelet make it possible to resolve a huge amount of detail, thanks to the lack of confusion caused by interference - in this case allowing dipping sediments to be traced right up to the water bottom.
The additional low frequencies provided by broadband data mean that a low frequency model from the well is not required for inversion, resulting in more quantitative results and higher confidence away from the well locations. Inversion of broadband data has been shown to provide better well ties, better correlation to geology and better resolution than inversion of conventional data.
In this post-stack inversion comparison from our Santos Basin multi-client survey in Brazil, the BroadSeis data show greater detail and dynamic range than the conventional data.
We take a two-sided approach to improving bandwidth. We actively generate a wider range of frequencies with our broadband seismic sources and we do our utmost to record them and preserve them during processing.
CGG has developed a range of broadband technologies across our product lines:
- BroadSeisTM combines equipment, acquisition and processing to deliver the broadest bandwidth in the industry, at over 6 octaves, to provide the sharpest wavelets and best resolution, as well as the added penetration and imaging power of boosted low frequencies.
- Broadband Land acquisition features mega channel counts, point sources and point receivers for denser sampling, improved noise attenuation and reduced acquisition footprint, to provide the finest resolution of the subsurface with the highest available spatial and temporal bandwidth. EmphaSeisTM tailored broadband sweeps extend the bandwidth to the maximum possible within the mechanical and hydraulic constraints of the vibrator. Broadband land data is now similar in appearance and spectral content to BroadSeis marine data.
- Subsurface Imaging uses advanced GWE (Ghost Wavefield Elimination) algorithms to maximize the spatial and temporal resolution of seismic data and maintain the full bandwidth, while attenuating noise and multiples. We provide various processing solutions to deghost and extend the bandwidth of legacy data, though these do not provide the authentic full bandwidth achieved by an acquisition solution.