Optimal Multiple Attenuation Flow for a Seismic Dataset in the Western Jeju Basin, Offshore Southern Korea

We acquired 2-D multichannel seismic data in the western Jeju Basin, offshore southern Korea. A 1380 in3 air-gun array produced seismic pulses. The shot spacing is 25 m. The number of channels is 156 and the group interval is 12.5 m. The length of the survey line is about 45 km. The water depth in this area is about 70 m. Since the water depth is very shallow, the raw data are severely contaminated with short-period water bottom multiples and noises. In order to attenuate these multiples and noises, we tested several combinations of processing modules to our marine seismic data. The overall workflow of the seismic data processing is composed of low-cut filter, spherical divergence correction, swell noise attenuation, Tau-p filtering, Tau-p deconvolution, surface-related multiple elimination (SRME), velocity analysis, Radon demultiple, and pre-stack time migration. Through the parameter testing, we have confirmed that the Tau-p filtering, the Tau-p deconvolution, and the SRME among the several demultiple techniques are very effective for the multiple attenuation in the study area. The Tau-p filtering is useful for attenuation of the linear noise in the near trace and the direct waves. The Tau-p deconvolution technique effectively attenuates the short-period multiples. The SRME efficiently eliminates the multiples contained in the near offsets. We could generate the multiple-suppressed pre-stack time migration section using our optimal seismic data processing flow. From the results, we have confirmed that our data processing sequences are effective in attenuating the multiples and improve the signal to noise ratio.