DATA PROCESSING & INTERPRETATION
streamer in a specific geometry configuration. Te cable ghost notch varies along the cable and this notch diversity is used by our patented new de-ghosting and imaging techniques to produce an ideal wavelet, with the best signal-to-noise ratio and best low-frequency content. It is this unique combination which provides the clearest seismic images, especially at depth, around key target locations.
Low noise characteristics Te BroadSeis solution capitalises on the extremely low-noise characteristics and precise low-frequency response of the Sentinel solid streamer. Solid streamers are quieter and can be towed deeper than other streamers (over 40m), meaning that BroadSeis provides better low frequencies. Tis is also supported by the new generation of Sentinel streamers that have lower instrument low-cut filters, which allow recording down to 2Hz, providing a full extra octave of data at low frequencies over previous systems.
control of solid streamers in BroadSeis mode is very robust and stable, especially when Nautilus is used, even at 45m. Te streamers retain their exceptional low-noise characteristics at all depths. As BroadSeis requires no new equipment where
solid streamers are already deployed, it is immediately available on most of the CGGVeritas fleet. Tere are fewer operational difficulties and, in addition, there is no loss in productivity due to having to tow additional streamers.
De-ghosting algorithm One of the unique features of BroadSeis is a new, fully 3D de-ghosting algorithm that makes no 2D assumptions and has no complications for de-ghosting ray paths in the crossline direction. Tis makes it uniquely ideal for 3D and all wide-azimuth acquisition configurations, as well as being possible for 2D data. Although the BroadSeis technique includes de- ghosting, it is possible to deliver raw field data to clients, giving them the option of applying any processing techniques desired, and offering them unrivalled flexibility. With its industry-first combination of an optimised and uniquely shaped solid streamer configuration with patented new de-ghosting and imaging algorithms, BroadSeis delivers a signal spectrum of unprecedented bandwidth. Te result is an exceptionally sharp and clean
wavelet for interpretation. Te notch diversity is designed and optimized for exploration and production targets, delivering the best possible resolution to interpreters. Te variability of the cable depth can be tuned for different water depths, target depths and desired output spectra. BroadSeis is suitable for all reservoirs, outperforming other industry solutions for high-definition broadband imaging.
Fig. 2. BroadSeis increases both the low and high ends of the spectrum.
Conventional wisdom believed that seismic sources did not produce sufficient low frequency to warrant recording below 5Hz, but recent data from the TIDES Tsunami Research survey project conducted by CGGVeritas in Indonesia clearly demonstrate that frequencies below 5Hz are being both emitted and recorded. As well as offering a quieter solution, with better signal-to-noise ratio and better low frequencies, BroadSeis uses fully-proven, readily-available equipment and is immediately operational. Te combination of Sercel Sentinel streamers
and Nautilus depth controllers is ideal for BroadSeis acquisition and leads to efficient operations. Te
As targets go deeper, BroadSeis can rely upon a larger useful bandwidth, particularly in the low- frequency range, for imaging beneath complex overburdens, etc. Conversely, for shallow targets, BroadSeis benefits fully from the total bandwidth available and recordable. Tis delivers the sharpest wavelet and the best resolving power in the industry as well as the added penetration and imaging power of boosted low frequencies. Te combination of Sentinel streamers, new towing geometries and breakthrough processing technology creates stunning final images of the subsurface. BroadSeis provides a simple, available and robust solution for broadband marine acquisition.
Enter 31 or ✔ at
www.engineerlive.com/ihss
Jo Firth is with CGGVeritas, Crawley, UK.
www.cggveritas.com www.engineerlive.com 31
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36