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Advances in Marine Seismic Acquisition

Mundy Brink
CGGVeritas, France
[email protected]

Three recent developments in marine seismic acquisition will be presented. The first is solid Previous HithydrophoneNext Hit cables and Sercel’s new navigation system. Due to their construction, the solid Previous HithydrophoneNext Hit cables better preserve low-frequency seismic signals, while the signal-to-noise ratio at the higher frequencies is improved by the dense spacing of the individual hydrophones. With these superior characteristics the recorded seismic data not only provide a better structural image of the subsurface geology, they also allow for a more reliable computation of rock parameters and pore fluids. The combination with Sercel’s new Nautilus System for integrated navigation and streamer positioning helps to more reliably record weak 4-D signals in reservoir monitor surveys. The solid cables also reduce risks to the environment, since they are not filled with oil. The second development is wide-azimuth acquisition, which yields a better image of complex geological structures. Some of the geophysical and operational experience will be presented. It allows for true 3-D processing like 3-D attenuation of multiples and multiple diffractions and derivation of fractures and their orientations. An efficient dual depth acquisition geometry is being introduced yielding extra enhancement of the lower frequencies. The third development is the application of feasibility studies to determine the optimal acquisition geometry for meeting the survey’s objectives. This can only be established after analysis of available data and modelling, done by specialists in different fields of geoscience. It may include towed Previous HithydrophoneTop cables or 4C seabed nodes or cables. Some examples will be shown.

 

AAPG Search and Discovery Article #90077©2008 GEO 2008 Middle East Conference and Exhibition, Manama, Bahrain