Wave-Equation Datuming Applied to Very High-Resolution Deep-Towed Multichannel Seismic Data

Understanding geohazards in great water depths requires the use of remotely deployed technologies in order to obtain the vertical and lateral resolutions required to model the medium. Deep-towed multichannel seismic is a powerful tool that can provide such resolutions, however data it produces requires careful, dedicated, processing. During acquisition of deep-towed seismic data, the vertical movements of the tow-fish cause vertical changes in the 120 m long streamer's shape. These variations have to be calculated to recover the acquisition geometry. This was solved by using travel times to invert for key parameters of the streamer's shape. Furthermore, unlike conventional surface-towed seismic, the sources and the receivers do not share the same depth datum which prevents the application of most conventional marine seismic processing algorithms. Wave-equation datuming (WED) is a method that allows moving the positions of sources and receivers to a common depth datum. This contribution presents how the WED method has been adapted to the characteristics of deep-towed multichannel seismic acquisitions. The application of this processing step to deep-towed seismic data allows the application of “conventional” algorithms, such as a NMO-stack-migration approach, thus facilitating the processing sequence of these unconventional seismic data.