Characteristics and noise combination suppression of wide-angle Ocean Bottom Seismography (OBS) data in shallow water : a case study of profile OBS2016 in the South Yellow Sea

A two-dimensional seismic survey was carried out in June 2016 along the east-west direction in the South Yellow Sea. We took the actual data processing of survey line (OBS2016) as an example to analyze the data characteristics in shallow water and the combined suppression method of noise in detail. The study shows that OBS data in shallow water have obvious differences in system time, energy and wavelet, and develop submarine multiple with notch. The signal-to-noise ratio of the original record is low, and a far offset seismic phase (>50 km) is difficult to identify and pick up. The noise combination suppression and processing technology used in this paper are mainly composed of wavelet shaping based on wavelet de-convolution, t-x linear noise suppression based on polynomial interpolation, and seabed multiple suppression using automatic searching. The purification results show the characteristics of the wave group are clear, the signal-to-noise ratio is greatly improved, and the range of recognized seismic phase is larger than that on the conventional records (more 60% on average). OBS data processing steps and processes aiming at the shallow water have been improved in this paper, which will provide reliable basic data for subsequent crustal structural research and better serve the deep crust, oil and gas resources exploration.