CGG Begins First Multi-Client Ocean Bottom Node Survey in Mississippi Canyon, Gulf of Mexico

Added: 28th May 2019 by CGG

CGG is pleased to announce commencement of its first multi-client ocean bottom node (OBN) survey. Located in the north-central region of the Gulf of Mexico, this dense OBN survey will provide exceptional data for imaging the geologically complex structures in the Mississippi Canyon.

Having seismic receivers stationary at the seabed has a number of advantages over towed-streamer seismic where the receivers are pulled behind the survey vessel. There is no noise arising from turbulence as the streamers are pulled through the water and no noise from the ocean swell or sea state; interference from reflections from the sea surface is less significant and easier to mitigate and shear S-waves, which cannot transmit through water can be recorded. There is also a greater diversity of recorded raypaths returning from the subsurface.

Shear waves are sensitive to fractures so provide information about fracture density and orientation which can indicate rock porosity and direction of likely fluid flow. They are also not attenuated by the presence of gas. The P-wave only OBN image suffers from problems caused by shallow gas, while the P-S wave OBN image is unaffected by the gas so provides a clearer image of the subsurface. Data courtesy PETRONAS Carigali Sdn. Bhd.