Imaging deep seafloor structures with reflection data from a low-energy and short-streamer seismic survey in the South Atlantic Ocean

Abstract The growth of seismic surveys using small airgun sources and short streamers has significantly reduced the costs and environmental impacts, but may limit the quality of reflection images. Using a 2D deep marine reflection survey in the South Atlantic with two small airguns and a 600-m-long streamer, we examine the challenges and solutions to imaging deep seafloor structures. The two main challenges are low signal-to-noise ratio and poor seismic illumination. In response, we performed noise attenuation methods such as de-swell and de-bubble to suppress noise through different processing steps. We also evaluate the impact of illumination on reverse-time migration and finite-difference migration methods. Furthermore, more challenges arise in association with limited source energy, short streamers, bio-interruptions, and 2D rather than 3D acquisition geometry. The data collected from such low-energy and short-streamer surveys require dedicated efforts to preserve seismic image fidelity against artifacts and position error. For imaging deep ocean sediments, our onboard monitoring based on brute stacks allowed timely identification of imaging issues, while post-survey processing focused on suppressing image artifacts due to airgun bubble reverberation, internal multiples, and sideswipe.