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Coupled thermo-hydro-mechanical and chemical (THMC) simulation of silicate rocks with an enriched–FEM model

Mortazavi, M. S ; Sharif University of Technology | 2024

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  1. Type of Document: Article
  2. DOI: 10.1016/j.compgeo.2024.106575
  3. Publisher: 2024
  4. Abstract:
  5. Numerical simulation of coupled Thermo-Hydro-Mechanical and Chemical (THMC) processes in deep Earth is an active field of research. In this study, a two-dimensional numerical model is developed based on the eXtended Finite Element Method (XFEM) to solve coupled reactive transport problems in saturated fractured rocks. According to high levels of heat and compaction in deep reservoirs, the Free-Face (FF) dissolution/precipitation as well as the Pressure Solution (PS) are considered for the aperture change in the formulation. The FF dissolution/precipitation refers to the mass exchange occurring at the free surfaces of the pores, whereas the PS takes place just among compacted grains and propping asperities due to chemo-mechanical effects. Herein, the reactive mineral is assumed quartz, producing aqueous silica after dissolution. To ensure the model is accurate enough, several validations are conducted against some analytical solutions as well as a benchmark experiment, which present satisfactory agreement. Subsequently, several case studies are conducted to explore the effects of temperature and fracture inclination on the aperture change. In addition, the mechanical and hydraulic influences of the surrounding medium on the chemical activities of fractures are demonstrated. It is concluded that neighboring fractures can change the PS reaction locally by mechanical effects; moreover, the ambient drainage can intensify the PS reaction in fractures. The results show the model is encouraging for prospective studies of reactive transport in geothermal systems, and the presented discussions shed light on some less-noticed and crucial aspects of chemo-mechanical activities in silicate rocks. © 2024 Elsevier Ltd
  6. Keywords:
  7. Reactive silica transport ; THMC simulation ; XFEM technique ; Dissolution ; Finite element method ; Geothermal fields ; Numerical methods ; Numerical models ; Porous materials ; Silica ; Silicate mineral ; Chemical simulations ; Flow-through test ; Fractured porous media ; Hydro-mechanical ; Mechanical simulations ; Reactive silica ; Reactive silicum transport ; Thermo-hydro-mechanical and chemical simulation ; Compaction ; Fractured medium ; Porous medium ; Pressure solution ; Reactive transport ; Reservoir rock ; Saturated medium ; Thermohydromechanics ; Fracture
  8. Source: Computers and Geotechnics ; Volume 173 , 2024 ; 0266352X (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0266352X24005147