The next Advances in 3D Marine Acquisition
De Kok, R.
EAGE Fall Research Workshop on Advances in Seismic Acquisition
Rhodes Greece, 20-23 September 2004
Advances in electronics enabled the acquisition of high fold 3D and 4D seismic data. Over the last decades, the number of recorded channels has increased continuously, while the cost per trace dropped correspondingly. In contrast, the number of sources has not been increased, rendering modern 3D surveys very asymmetric in terms of spatial sampling. The paper describes a novel concept that will aid in improving the sampling conditions. It also describes a method for improving the vertical resolution in a cost effective manner.
By using a lateral array of sources firing in a coded manner (See ‘The universal simultaneous shooting method’) and using these in combination with multiple parallel streamers, the spatial sampling can drastically be improved. Discrimination of the source array elements is not critical as cross-talk will merely manifest itself as side-lobe energy. The vertical resolution of marine seismic data is severely compromised by the sea-surface ghosts at the source and receiver ends. An efficient method (Quasi Over-Under) for the use of sources and streamers towed at different depth is described. Through the Quasi Over Under method, the band limiting ghost notches can be eliminated.