Case Study Example of Multiple Attenuation for Over/Under Streamer Data

In a recent experiment in the North Sea, data were acquired with a streamer towed at conventional depth, as well as with a pair of deeper streamers, towed in so-called over/under configuration. The main benefits expected from the over/under streamers are lower levels of swell noise in the data and suppression of the receiver-side ghost. In the theoretical section of the paper, we discuss the implications of deghosting on predicted surface multiples; the absence of deghosting during preprocessing may introduce inconsistencies between the model of the multiples and the data, which render the subtraction of multiples less reliable. In the case study example, we build upon previously published results by adding attenuation of free-surface multiples (2D SRME) in the processing sequence. As in previous work, the quality of the stack from the over/under data is better than the stack from the shallow streamer data. Improvements in multiple attenuation on the over/under data are not as readily identified as expected, but the detailed interpretation and comparison of multiple attenuation results is still in progress.