Geophysics and Geophysical Exploration (지구물리와물리탐사)

Korean Society of Earth and Exploration Geophysicists (한국지구물리·물리탐사학회)
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Shallow Gas Exploration in the Pohang Basin Transition Zone

포항분지 전이대에서 천부가스 탐사

  • 이동훈 (한국지질자원연구원 해저지질에너지연구본부) ;
  • 김병엽 (한국지질자원연구원 해저지질에너지연구본부) ;
  • 김지수 (충북대학교 지구환경과학과) ;
  • 장성형 (한국지질자원연구원 해저지질에너지연구본부)
  • Received : 2021.12.03
  • Accepted : 2022.02.24
  • Published : 2022.02.28
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Abstract

For surveying shallow gas reservoirs in the Pohang basin, we proposed a seismic exploration method applicable to the transition zone in which land and marine areas are connected. We designed the seismic acquisition geometry considering both environments. We installed land nodal receivers on the ground and employed vibroseis and airgun sources in both land and marine areas. For seismic exploration in the transition zone, specific acquisition and processing techniques are required to ensure precise matching of reflectors at the boundary between the onshore and offshore regions. To enhance the continuity of reflection events on the seismic section, we performed amplitude and phase corrections with respect to the source types and applied a static correction. Following these processing steps, we obtained a seismic section showing connected reflectors around the boundary in the transition zone. We anticipate that our proposed seismic exploration method can also be used for fault detection in the transition zone.

포항분지 천부가스 탐사를 위해 육상과 해상이 연결되는 전이대에서 탄성파 탐사 방법을 제안하고 탐사를 수행하였다. 해저면 환경, 육상 탐사 환경을 고려하여 탐사를 설계하였다. 육상노드 수진기는 육상에만 설치하였고 육상에서는 바이브로사이스 음원을, 해양에서는 에어건 음원을 이용하여 자료를 취득하였다. 전이대에서 취득한 탄성파 탐사자료의 경우 육상탐사와 해상탐사 간의 정확한 연계를 위해 신중한 자료 취득과 처리 과정이 필요하다. 음원 종류에 따른 진폭과 위상변화를 고려하고, 음원위치에 따른 정적보정을 적용한 자료처리를 통해 지층단면도에서 반사파 연속성이 유지되게 하였다. 자료처리 결과 육상과 해상의 지층구조가 연결된 탄성파 지층단면도를 확보하고 포항분지 천부 가스층 탐사에 활용하고자 하였다. 전이대에서 탄성파 탐사는 천부가스뿐만 아니라 연안지역 단층대 조사에도 활용할 수 있을 것으로 기대된다.

Keywords

Acknowledgement

이 연구는 과학기술정보통신부 산하 한국지질자원연구원 기본사업인 "교통차량 진동을 이용한 도심 지질탐사 및 상시모니터링 기술개발(GP2020-034)" 과제 지원과 산업통상자원부(MOTIE) 한국에너지기술평가원(KETEP)의 지원(No. 20172510102160)으로 수행되었습니다.

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