Development of small vessel 3D seismic survey system: EOS3D

Korea Institute of Geoscience and Mineral Resources (KIGAM) has been developing 3D seismic survey systems for near-coastal zone which can be operated by small ship in two tracks. First track is EOS3D-Wing (Engineering Ocean Seismic 3 Dimension-Wing)) for detecting small abnormal objects buried in shallow offshore area (less than 10 m). Vertical resolution is maximized by using high-frequency range (> 5kHz) sources (e.g., Boomer, SBP, Chirp). Surveying coverage is dramatically enhanced by designing a 16 m-long wing-shaped receiver frame having 12 channels. EOS3D-Wing can be utilized for various activities performed in near-coastal area such as submarine cable monitoring, marine aggregate investigation, underwater archaeology, and coast management. In 2015, KIGAM reconstructed 3D shape of old vessel wrecked 600 years ago (in the Joseon Dynasty period) using EOS3D-Wing, and this attracted a lot of attention of international underwater archaeology communities. Second track is EOS3D-Streamer (Engineering Ocean Seismic 3 Dimension-Streamer) for visualizing geological features of shallow area. Penetration depth of elastic wave emitted by source is maximized by using middle-frequency range (< 5kHz) powerful sources (e.g., Airgun, Sparker). This system is in similar form of the conventional seismic survey system in oil and gas industry, but it has two 86m-long receiver streamers having 16 channels. EOS3D-Streamer can be utilized for detecting various geological features such as fault, unconformity, and acoustic basement. This also can be used for shallow gas exploration, geological loss study, stability analysis of various engineering works. In 2016, KIGAM succeeded in generating 3D cube of subsurface structures having many shallow faults and free gas areas in the eastern coast of Korea. Basic structure and operation method of both system mentioned above are already established with various feasibility studies, but they are still improving in four concepts which are real-time, portable, internet of things, and unmanned automation.