BroadSeisTM, the CGGVeritas broadband marine solution, continues to provide exceptional broadband images in different geological settings.
Since its launch at the Barcelona EAGE convention, BroadSeis has generated considerable interest. Eight projects have now been recorded in various locations around the world, from Australia to the Arctic. These include both 2D and 3D geometries in a variety of geological settings, water depths and target depths. These surveys are both proprietary and non-proprietary and clients include a number of major oil companies.
Deepwater data examples from West Africa and the Gulf of Mexico were shown at the recent SEG convention, providing exceptional bandwidth of 2.5 – 155Hz, almost 6 octaves of data. These results included true amplitude deghosted gathers, suitable for AVO analysis.
BroadSeis acquires both low and high frequencies simultaneously using Sercel Sentinel® solid streamers with a variable depth profile (patent pending). The cable ghost notch varies along the streamer with the cable depth and our new proprietary deghosting and imaging techniques (patents pending) use this notch diversity to produce a very sharp wavelet, with a superior signal-to-noise ratio and the maximum bandwidth.
The low-noise characteristics and precise low-frequency response of Sentinel streamers have proved central to the success of BroadSeis. Sentinel is quieter and can be towed deeper than other streamers (up to 60m). Since Sentinel has an instrument low-cut of 2Hz, BroadSeis provides significantly better low frequencies, recording high-quality signal down to at least 2.5Hz.
A key feature of BroadSeis is that the cable depth profile can be tuned for different water depths and targets so that the notch diversity and output spectra are optimized for each survey. Operational experience has shown that the control of solid streamers to variable depths is robust and stable for both 2D and 3D configurations, even down to 60m, especially when using Sercel Nautilus® streamer control devices. This has been proven even in areas with variable currents such as the Gulf of Mexico and variable salinity conditions such as West Africa. Sentinel has retained its exceptional low-noise characteristics at all depths, with all streamer profiles and under all conditions.
BroadSeis includes a new, true-amplitude, fully-3D deghosting algorithm that makes no 2D assumptions. This gives it unrivalled suitability for 3D and all wide-azimuth acquisition configurations, as well as 2D data. While the proprietary deghosting is a part of the BroadSeis technique, the raw field data are supplied to clients providing them with flexibility to apply any processing techniques desired.
From shallow objectives to deep targets beneath complex overburdens, BroadSeis is delivering data with exceptional bandwidths and excellent penetration. For clearer imaging of deep targets, as well as greater stability in seismic inversion, providing reduced exploration risk, BroadSeis is proving to be the Safer, Broader, Better choice for marine acquisition and processing.
Find out more about BroadSeis at the CGGVeritas booth #C10, or visit: www.cggveritas.com/BroadSeis.