SEISMIC IMAGING OFFSHORE POHANG USING SMALL-BOAT ULTRA-HIGH-RESOLUTION 3D SEISMIC SURVEY

Abstract

A joint study by the Korea Institute of Geoscience and Mineral Resources (KIGAM) and Geoview Co. Ltd. has developed a new 3D ultra-high-resolution (UHR) seismic survey system called the Engineering Ocean Seismic 3D-Streamer (EOS3D-Streamer). The EOS3D-Streamer is a receiver system comprising two, 8-channel 93 meter streamers that are used in conjunction with a small air gun system as a seismic source. To verify the new system, a test survey was performed over two years in 2016 and 2017 in Pohang City's Yeongil Bay located offshore the southeastern part of Korea. In the test survey, 139 lines of seismic data were acquired in a survey region of 1,400 m x 500 m. A basic seismic data processing algorithm was applied to the data that was divided by channel. Subsequently, a 3D seismic cube was produced for each channel using a radial basis function (RBF) interpolation method in a stage of 3D flexi-binning. A final 3D cube with an improved signal to noise ratio was produced after normal move-out correction using a 1D velocity model and multi-channel stacking. Finally, a shallow fault and gas analysis was performed through a data interpretation process. Through this study, we confirmed that it is possible to perform economical UHR 3D surveys using general-purpose small vessels in coastal areas where it is difficult for large seismic vessels to enter and perform surveys.