All Issue

2018 Vol.28, Issue 6 Preview Page
December 2018. pp. 670-691
Abstract

본 논문에서는 국제공동연구 DECOVALEX-2019 프로젝트의 일환으로 수행된 Task B Benchmark Model Test(BMT)의 연구 결과를 소개하였다. Task B는 ‘Fault slip modelling’을 연구주제로 하며, 유체의 주입으로 인해 발생하는 단층의 재활성과 수리역학적 연계거동을 예측할 수 있는 해석기법을 개발하는 데에 목적이 있다. BMT 시나리오 해석은 각 참가팀들의 수치모델이 단층의 수리역학적 연동거동을 적절히 모사할 수 있는지 교차검증함으로써 각 해석코드의 완성도를 높이기 위하여 수행되었으며, 주입압 적용 조건, 단층 물성, 수리역학적 연동해석 조건 등에 따라 7개의 해석 모델로 이루어져 있다. 본 연구에서는 TOUGH-FLAC 연동해석 기법을 이용하여, 역학적 변형으로 야기되는 단층의 수리적 물성 변화와 간극의 기하학적 변화를 동시에 반영할 수 있는 수리역학적 커플링 모듈을 개발하였다. BMT 시나리오 해석을 위하여 Task B 1단계(Step 1) 연구에서 개발된 수치모델을 일부 수정하였고, 단층의 변형에 따른 압축률과 투수계수, 단층의 해석 메쉬의 변화가 해석에 반영될 수 있도록 하였다. 단층의 투수량계수와 저류계수가 단층 내 압력 분포, 주입수량, 변위, 응력 등 수리역학적 거동에 미치는 영향을 검토하였으며, 수정된 수치모델을 기수행된 1단계 연구에 적용하여 해석결과를 업데이트하였다. 해석 결과, 본 연구에서 개발한 해석기법이 물 주입으로 인한 단층의 거동을 합리적인 수준에서 재현할 수 있는 것으로 판단할 수 있었다. 본 연구의 해석모델은 Task B에 참여하는 국외 연구팀들과의 의견 교류와 워크숍을 통해 지속적으로 개선하는 한편, 향후 연구의 현장시험에 적용하여 타당성을 검증할 예정이다.

This study presents the research results of the BMT(Benchmark Model Test) simulations of the DECOVALEX-2019 project Task B. Task B named ‘Fault slip modelling’ is aiming at developing a numerical method to predict fault reactivation and the coupled hydro-mechanical behavior of fault. BMT scenario simulations of Task B were conducted to improve each numerical model of participating group by demonstrating the feasibility of reproducing the fault behavior induced by water injection. The BMT simulations consist of seven different conditions depending on injection pressure, fault properties and the hydro-mechanical coupling relations. TOUGH-FLAC simulator was used to reproduce the coupled hydro-mechanical process of fault slip. A coupling module to update the changes in hydrological properties and geometric features of the numerical mesh in the present study. We made modifications to the numerical model developed in Task B Step 1 to consider the changes in compressibility, Permeability and geometric features with hydraulic aperture of fault due to mechanical deformation. The effects of the storativity and transmissivity of the fault on the hydro-mechanical behavior such as the pressure distribution, injection rate, displacement and stress of the fault were examined, and the results of the previous step 1 simulation were updated using the modified numerical model. The simulation results indicate that the developed model can provide a reasonable prediction of the hydro-mechanical behavior related to fault reactivation. The numerical model will be enhanced by continuing interaction and collaboration with other research teams of DECOVALEX-2019 Task B and validated using the field experiment data in a further study.

References
  1. Bohloli, B., Choi, J.C., Skurtveit, E., Grande, L., Park, J., Vannest, M., 2015, Criteria of fault geomechanical stability during a pressure buildup, IEAGHG report 2015/04. Cheltenham, UK.
  2. Cappa, F., Rutqvist, J., 2011, Modeling of coupled deformation and permeability evolution during fault reactivation induced by deep underground injection of CO2, International Journal of Greenhouse Gas Control, Vol. 5, pp. 336-346.10.1016/j.ijggc.2010.08.005
  3. Cuisiat, F., Jostad, H.P., Andresen, L., Skurtveit, E., Skomedal, E., Hettema, M., Lyslo, K., 2010, Geomechanical integrity of sealing faults during depressurization of the Statfjord field, Journal of Structural Geology, Vol. 32, pp. 1754-1767.10.1016/j.jsg.2010.01.006
  4. Gudmundsson, A., 2004, Effects of Young's modulus on fault displacement. Comptes Rendus Geoscience, Vol. 336, pp. 85-92.10.1016/j.crte.2003.09.018
  5. Guglielmi, Y., Elsworth, D., Cappa, F., Henry, P., Gout, C., Dick, P., Durand, J., 2015, In situ observations on the coupling between hydraulic diffusivity and displacements during fault reactivation in shales, Journal of Geophysical Research: Solid Earth, Vol. 120, pp. 7729–7748.10.1002/2015JB012158
  6. Gutierrez, M., Makurat, A., 1997, Coupled HTM modelling of cold water injection in fractured hydrocarbon reservoirs, International Journal of Rock Mechanics and Mining Sciences, Vol. 34, pp113.e1-113.e15n
  7. Kim, H.M., Rutqvist, J., Ryu, D.W., Choi, B.H., Sunwoo, C., Song, W.K., 2012, Exploring the concept of compressed air energy storage (CAES) in lined rock caverns at shallow depth: A modeling study of air tightness and energy balance, Applied Energy, Vol. 92, pp. 653-667.10.1016/j.apenergy.2011.07.013
  8. Leijon, B., 1993, Mechanical properities of fracture zones, SKB Technical Report TR 93-19.
  9. Morris, J.P., Hao, Y., Foxall, W., McNab, W., 2011, A study of injection-induced mechanical deformation at the In Salah CO2 storage project, International Journal of Greenhouse Gas Control, Vol. 5, pp. 270-280.10.1016/j.ijggc.2010.10.004
  10. Orlic, B., Heege, J., Wassing B., 2011, Assessing the integrity of fault- and top seals at CO2 storage sites, Energy Procedia, Vol. 4, pp. 4798-4805.10.1016/j.egypro.2011.02.445
  11. Park, J.W., Rutqvist, J., Ryu, D.W., Park, E.S., Synn, J.H., 2016, Coupled thermal-hydrological-mechanical behavior of rock mass surrounding a high-temperature thermal energy storage cavern at shallow depth, International Journal of Rock Mechanics & Mining Sciences, Vol. 83, pp. 149-161.10.1016/j.ijrmms.2016.01.007
  12. Park, J.W., Park, E.S., Kim, T., Lee, C., Lee, J., 2018, Hydro-mechanical modelling of fault slip induced by water injection: DECOVALEX-2019 Task B (Step 1), Tunnel & Underground Space, Vol. 28, pp. 400-425.
  13. Peng, H.-Y., Yeh, H.-D, Yang, S.-Y., 2002, Improved numerical evaluation of the radial groudwater flow equation, Advances in Water Resources, Vol. 25, pp. 663-675.10.1016/S0309-1708(02)00030-1
  14. Rinaldi, A.P., Rutqvist, J., Cappa, F., 2014, Geomechanical effects on CO2 leakage through fault zones during large-scale underground injection, International Journal of Greenhouse Gas Control, Vol. 20, pp. 117-131.10.1016/j.ijggc.2013.11.001
  15. Rutqvist, J., Dobson, P.F., Garcia, J., Hartline, C., Jeanne, P., Oldenburg, C.M., Vasco, D.W., Walters, M., 2015, The northwest Geysers EGS demonstration project, California: Pre-stimulation modeling and interpretation of the stimulation. Mathematical Geosciences, Vol. 47, pp. 3-29.10.1007/s11004-013-9493-y
  16. Rutqvist, J., Graupner, B., Guglielmi, Y., 2017, Fault Slip Test - Modelling the induced slip of a fault in argillaceous rock - Discussion, Presentation at the 4th workshop of DECOVALEX-2019, Kingston, UK.PMC5357467
  17. Rutqvist, J., 2012, Status of the TOUGH-FLAC simulator and recent applications related to coupled fluid flow and crustal deformations, Computers & Geosciences, Vol. 37, pp. 739-750.10.1016/j.cageo.2010.08.006
  18. Rutqvist, J., Tsang, C.F., 2012, Multiphysics processes in partially saturated fractured rock: Experiments and models from Yucca Mountain. Reviews of Geophysics, Vol. 50, RG3006.10.1029/2012RG000391
  19. Rutqvist, J., Wu, Y-S. Tsang, C.F., Bodvarsson, G., 2002, A modeling approach for analysis of coupled multiphase fluid flow, heat transfer, and deformation in fractured porous rock, International Journal of Rock Mechanics and Mining Sciences, Vol. 39, pp. 429-442.10.1016/S1365-1609(02)00022-9
  20. Vidal-Gilbert, S., Nauroy, J.-F., Brosse, E., 2009, 3D geomechanical modelling for CO2 geologic storage in the Dogger carbonates of the Paris Basin. International Journal of Greenhouse Gas Control, Vol. 3, pp. 288-299.10.1016/j.ijggc.2008.10.004
  21. Witherspoon, P.A., Wang, J.S.Y., Iwai, K., Gale, J.E., 1980, Validity of cubic law for fluid flow in a deformable rock fracture, Water Resources Research, Vol. 16, pp. 1016-1024.10.1029/WR016i006p01016
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 : 28
  • No :6
  • Pages :670-691
  • Received Date :2018. 12. 14
  • Accepted Date : 2018. 12. 21