A Hydro-Mechanical Basic Study on the Effect of Shut-in on Injection-Induced Seismic Magnitude

Juhyi Yim; Ki-Bok Min

doi:10.7474/TUS.2022.32.3.203

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2022 Vol.32, Issue 3 Preview Page Next Page

Original Article

A Hydro-Mechanical Basic Study on the Effect of Shut-in on Injection-Induced Seismic Magnitude 유체 주입 중단이 유발 지진 규모에 미치는 영향에 대한 수리역학적 기초 연구

30 June 2022. pp. 203-218

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Abstract

A hydro-mechanical study was performed to analyze the relationship between the magnitude of injection-induced seismicity and shut-in. In hydraulic analysis, the suspension of fluid injection makes the pore pressure gradient smaller while the pore pressure at the pressure front can reach the critical value for several hours after shut-in, which leads to the additional slip with wider area than during injection. The hydro-mechanical numerical analysis was performed to model the simplified fault system, and simulated the largest magnitude earthquake during shut-in stage. The effect of the abrupt suspension of fluid injection on the large magnitude earthquake was investigated in comparison with the continuous injection. In addition to the pore pressure distribution, it was found that the geometry of multiple faults and the stress redistribution are also important in evaluating the magnitude of the induced seismicity.

Keywords

Induced seismicity

EGS

Numerical analysis

Hydraulic stimulation

Fluid injection

본 연구에서는 유체 주입 중단과 유발 지진 규모의 관계에 대하여 수리역학적으로 분석하였다. 수리적 해석을 통해 공극압의 구배가 유체 주입 중단으로 인해 완만해짐과 동시에 주입 중단 이후에도 수 시간동안 압력 선두에서 상당한 임계 공극압에 도달하면서 더 넓은 영역에서 추가적인 전단을 일으킬 수 있음을 확인하였다. 수리역학 복합 해석을 단순화된 균열모델에 적용함으로써 유체 주입 중단 후에 최대 규모의 지진이 발생하는 것을 모사하였고, 유체 주입을 유지하는 경우와의 비교를 통해 급작스런 유체 주입 중단이 지진 유발에 미치는 영향을 분석하였다. 또한 공극압의 분포 이외에도 단층 간의 기하학적 관계와 응력 재분배 등에 의해 임계 공극압의 구배가 변하며 이것이 유발 지진의 규모 평가에 중요하게 고려되어야 함을 확인하였다.

키워드

유발 지진

EGS

수치해석

수리 자극

유체 주입

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Information

Publisher :Korean Society for Rock Mechanics and Rock Engineering
Publisher(Ko) :한국암반공학회
Journal Title :Tunnel and Underground Space
Journal Title(Ko) :터널과 지하공간
Volume : 32
No :3
Pages :203-218
Received Date : 2022-04-19
Revised Date : 2022-06-23
Accepted Date : 2022-06-23
DOI :https://doi.org/10.7474/TUS.2022.32.3.203

Tunnel and Underground Space ISSN:1225-1275(Print) 2287-1748(Online) 터널과 지하공간

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