Economic and Environmental Geology (자원환경지질)

The Korean Society of Economic and Environmental Geology (대한자원환경지질학회)
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Thermo-hydraulic Modeling in Fault Zones

단층대에서의 열-수리적 거동 모델링

  • Published : 2009.12.28
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Abstract

High permeable faults are important geological structures for fluid flow, energy, and solute transport. Therefore, high permeable faults play an important role in the formation of hydrothermal fluid (or hot spring), high heat flow, and hydrothermal ore deposits. We conducted 2-D coupled thermal and hydraulic modeling to examine thermohydraulic behavior in fault zones with various permeabilities and geometric conditions. The results indicate discharge temperature in fault zones increases with increasing fault permeability. In addition, discharge temperature in fault zones is linearly correlated with Peclet number ($R^2=0.98$). If Peclet number is greater than 1, discharge temperature in fault zones can be higher than $32^{\circ}C$. In this case, convection is dominant against conduction for the heat transfer in fault zones.

지층 내에 발달한 고투수성 단층은 유체, 에너지, 그리고 용질이 이동하는데 있어서 중요한 역할을 하는 지질구조이다. 따라서 고투수성 단층 주변부에서는 지열수(혹은 온천), 지열 이상대, 그리고 금속 광상 등이 형성될 가능성이 크다. 단층의 구조에 따른 지하수 유동과 이에 따른 지층 내의 열적 상태를 확인하기 위해서 단층 구조가 다른 세 가지의 경우에 대해서 이차원 열-수리적 거동 모델링을 수행하였다. 모델링 결과로부터 세 가지 모든 단층 구조의 경우에서 단층의 투수율이 커지면 단층대에서의 지하수 용출 온도가 초기 온도 보다 높아지는 경향을 확인 할 수 있다. Peclet number 와 단층대에서의 용출온도의 상관관계 분석으로부터 상관계수($R^2$)가 0.98로 상당히 높은 것을 확인하였다. Peclet number가 1이상 일 때 단층대에서는 약 $32^{\circ}C$ 이상의 온도가 용출되며 이러한 경우에 단층대에서의 열흐름은 매질을 통한 전도 보다는 지하수에 의한 대류의 영향이 큰 것으로 판단된다.

Keywords

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