Discussion on Deep 3D Seismic Data Acquisition Techniques in Xihu Sag, East China Sea

In recent years, great progress has been made in the deep structural-lithological reservoir exploration and development in Xihu Sag, East China Sea. Du to low signal-to-noise-ratio and imaging challenges, the legacy 3D data acquired by NATS (narrow azimuth towed streamer) with one vessel restricted the identification, description and evaluation of deep targets. So sereral WATS (wide azimuth towed streamer) acquisitions with different configurations were carried out. As typical examples, HY WATS and BT WATS are used for making analysis on acquisition attributes and comparisons of contributions to imaging of deep targets with different azimuths. The results demonstrate that the azimuths of the existing WATS appear much sparser; under the conditions of narrow azimuth (NAZ), the high density tower streamer 3D data by smaller cell size, longer cable and higher fold will provide a limited improvement of imaging of deep targets; the wider azimuthal data can improve deep imaging. OBN acquisition technology with wider azimuth and higher signal-to-noise ratio can be adopted in the next step in Xihu Sag.The study has reference significance for the selection of seismic acquisition schemes in Xihu Sag.