지구물리와물리탐사 (Geophysics and Geophysical Exploration)

  • 제24권4호
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  • Pages.180-193
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  • 2021
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  • 1229-1064(pISSN)
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  • 2384-051X(eISSN)
한국지구물리·물리탐사학회 (Korean Society of Earth and Exploration Geophysicists)
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복소 전기비저항 3차원 역산 알고리듬 개발

Development of Three-dimensional Inversion Algorithm of Complex Resistivity Method

  • 손정술 (한국지질자원연구원 광물자원연구본부 자원탐사개발연구센터) ;
  • 신승욱 (한국지질자원연구원 광물자원연구본부 자원탐사개발연구센터) ;
  • 박삼규 (한국지질자원연구원 글로벌협력본부)
  • Son, Jeong-Sul (Mineral Resources Development Research Center, Mineral Resources Division, Korea Institute of Geoscience and Mineral Resources (KIGAM)) ;
  • Shin, Seungwook (Mineral Resources Development Research Center, Mineral Resources Division, Korea Institute of Geoscience and Mineral Resources (KIGAM)) ;
  • Park, Sam-Gyu (Global Cooperation Division, Korea Institute of Geoscience and Mineral Resource (KIGAM))
  • 투고 : 2021.10.01
  • 심사 : 2021.11.17
  • 발행 : 2021.11.30
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초록

복소 전기비저항 탐사기법은 진동수 영역에서 전기비저항과 위상을 측정하여 지하 매질의 다양한 특성정보를 획득할 수 있는 탐사기법으로 최근 그 활용성이 증가하고 있다. 이 논문에서는 복소 전기비저항 탐사기법의 활용성을 높이기 위하여 획득한 자료에 대한 3차원 역산 알고리듬을 개발하였다. 이를 위한 모델링에는 전자기 커플링 효과를 무시하는 경우에 적용할 수 있는 포아송 방정식을 적용하였으며, 역산에는 기존의 평활화된 역산법을 복소수로 확장하는 방법으로 알고리듬을 개발하였다. 역산의 안정성 및 현장자료의 적용성을 높이기 위하여 라그랑지 곱수를 역산 과정에서 오차 벡터와 모델 증분 벡터의 크기에 따라 자동적으로 조정되도록 하는 기법을 도입하였다. 또한, 잡음이 많이 포함된 위상자료로 인한 자료의 손실을 보완하기 위하여 역산반복 단계에서 초반부는 전기비저항 자료만을, 후반부는 전기비저항 자료와 위상 자료를 모두 역산하는 두 단계로 구성된 역산기법을 제시하였다. 수치 모형실험에 대한 역산 시험결과 안정적인 역산 결과를 얻을 수 있었으며, 개발된 3차원 역산 알고리듬을 국내 천열수 광산 인근에서 수행한 복소 전기비저항 탐사자료 해석에 적용하여 그 타당성을 확인하였다.

The complex resistivity method is an exploration technique that can obtain various characteristic information of underground media by measuring resistivity and phase in the frequency domain, and its utilization has recently increased. In this paper, a three-dimensional inversion algorithm for the CR data was developed to increase the utilization of this method. The Poisson equation, which can be applied when the electromagnetic coupling effect is ignored, was applied to the modeling, and the inversion algorithm was developed by modifying the existing algorithm by adopting comlex variables. In order to increase the stability of the inversion, a technique was introduced to automatically adjust the Lagrangian multiplier according to the ratio of the error vector and the model update vector. Furthermore, to compensate for the loss of data due to noisy phase data, a two-step inversion method that conducts inversion iterations using only resistivity data in the beginning and both of resistivity and phase data in the second half was developed. As a result of the experiment for the synthetic data, stable inversion results were obtained, and the validity to real data was also confirmed by applying the developed 3D inversion algorithm to the analysis of field data acquired near a hydrothermal mine.

키워드

과제정보

이 연구는 한국지질자원연구원 기본사업인 "국내 바나듐(V) 등 에너지 저장광물 정밀탐사기술 개발 및 부존량 예측" 과제 (GP2020-007)의 일환으로 수행되었습니다.

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