Numerical Modeling of Serpentinization and the Implication on Reaction Induced Cracking

ABSTRACT: A key question in understanding the feasibility of mineral carbon storage in low permeability ultramafic rocks is how to create hydraulic pathways and reactive surface areas to enhance the reservoir permeability and to assist hydration and carbonation reactions to maximize the carbon storage potential. A hydro-chemo-mechanically coupled numerical analysis is conducted to examine the serpentinization process to better understand the interplay between reactive transport and the mechanical feedback. Four series of numerical simulations are performed to investigate the effects of crucial reactive transport parameters, e.g., the reaction rate constant and the diffusion coefficient, the mechanical and chemical boundary conditions, and the initial contrast in the degree of serpentinization in the domain on the stress field that can be generated due to mineral transformation. The numerical results indicate that reaction induced cracking is possible in volume expansion type of reactions. Initial contrast in the degree of serpentinization in the host rock promotes the development of tensile failure. These numerical results offer valuable insights into the fracture development and vein formation mechanisms in serpentinized ultramafic rocks in the natural environment and help shed light on the feasibility in engineering mineral carbon storage.