Tunnel and Underground Space (터널과지하공간)

Korean Society for Rock Mechanics and Rock Engineering (한국암반공학회)
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Numerical Analysis of Fault Stability in Janggi Basin for Geological CO2 Storage

CO2 지중저장에 따른 장기분지 내 단층안정성 기초해석

  • Jung-Wook Park (Korea Institute of Geoscience and Mineral Resources) ;
  • Hanna Kim (Korea Institute of Geoscience and Mineral Resources) ;
  • Hangbok Lee (Korea Institute of Geoscience and Mineral Resources) ;
  • Chan-Hee Park (Korea Institute of Geoscience and Mineral Resources) ;
  • Young Jae Shinn (Korea Maritime and Ocean University)
  • Received : 2023.08.11
  • Accepted : 2023.09.07
  • Published : 2023.10.31
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Abstract

The present study conducted a numerical modeling of CO2 injection at the Janggi Basin using the TOUGH-FLAC simulator, and examined the hydro-mechanical stability of the aquifer and the fault. Based on the site investigations and a 3D geological model of the target area, we simulated the injection of 32,850 tons of CO2 over a 3-year period. The analysis of CO2 plume with different values of the aquifer permeability revealed that assuming a permeability of 10-14 m2 the CO2 plume exhibited a radial flow and reached the fault after 2 years and 9 months. Conversely, a higher permeability of 10-13 m2 resulted in predominant westward flow along the reservoir, with negligible impact on the fault. The pressure changes around the injection well remained below 0.6 MPa over the period, and the influence on the hydro-mechanical stability of the reservoir and fault was found to be insignificant.

본 연구에서는 TOUGH-FLAC 연동해석 기법을 사용하여 장기분지 유망 저장소 부지에서의 CO2 주입을 수치적으로 모델링하고, 주변 지층과 단층에 야기되는 수리-역학적 안정성을 검토하였다. 대상부지의 현장조사와 3D 지질모델을 기반으로 3년간 32,850톤의 CO2 주입을 가정하여 시뮬레이션을 수행하였다. 저류층의 투수계수에 따른 CO2 플럼의 유동 경로를 분석한 결과, 투수계수를 10-14 m2로 가정한 경우 방사형 유동을 보이며 2년 9개월 경과 시 단층에 도달하는 것으로 나타났다. 투수계수를 10-13 m2로 가정한 경우에는 저류층을 따라 서쪽 방향의 유동이 우세하게 나타났으며 단층 방향으로의 유동은 거의 발생하지 않았다. 주입공 주변의 압력 변화는 3년 동안 0.6 MPa 이하로, 지층 및 단층의 역학적 안정성에 미치는 영향은 미미한 것으로 분석되었다.

Keywords

Acknowledgement

본 연구는 한국지질자원연구원의 기본사업인 '심지층 개발과 활용을 위한 지하심부 특성평가 기술개발(과제코드: GP2020-010)' 사업과 'CO2 지중저장소 저장효율 향상 및 안전성 평가 기술 개발(과제코드: GP2020-025)' 사업의 지원을 받아 수행되었습니다.

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