Deep Imaging with a New Method for Efficient 3D Broadband Marine Acquisition and Processing

We present a new method for broadband marine acquisition and processing capable of imaging deep targets while maintaining full high frequency bandwidth data. The method uses a deep interpolated streamer coverage approach (DISCover), which comprises a 3D shallow towed-streamer spread, designed to optimize the mid- and high-frequency parts of the bandwidth, together with data simultaneously acquired from a small number of deeper towed streamers. The depth of these deeper streamers is optimized for the low frequencies such that the combined overall bandwidth is enhanced. Because the deep streamers are only going to provide the low-frequency part of the bandwidth, we can more sparsely sample these data thus enabling efficient acquisition scenarios as fewer streamers are required. A 3D case study using this new acquisition method was acquired off the NW Shelf of Australia. The streamer spread consisted of six shallow streamers towed at a depth of 6m and two deeper streamers (below shallow streamers 2 and 5) towed at a depth of 20m. The resulting data exhibit both high resolution and deep penetration for subsalt and sub-basalt imaging, for example. Inversion for acoustic impedance, imaging, and velocity model building, also benefit from the broadband result.