Cracking the Code: Harnessing Serpentinization-Driven Micro-Crack Networks for Hydrogen Generation and Subsurface Resource Recovery

This study focuses on simulating volume-increasing processes caused by natural hydrogen-generating serpentinization, a reaction in which olivine and pyroxene typically transform into serpentine minerals. The volume increase leads to crack propagation along grain interfaces and new crack generation within unreacted crystals (aka grains). The interplay between thermo-hydro-mechanical-chemical (THMC) conditions plays a critical role in the initiation, propagation, and coalescence of various fracture surfaces, which enhances permeability and can accelerate serpentinization and hydrogen production rates. In the scenarios considered, chemical reactions between formation brine and reactive minerals result in volumetric expansion, generating stress and promoting the propagation of micro-cracks. Our results show that these micro-cracks can progressively evolve into intricate networks, depending on local stress conditions, material properties, fluid transport, and reaction kinetics. Importantly, if THMC processes can be engineered to optimize these dynamics, they could lead to a commercially viable approach for in-situ hydrogen generation, leveraging naturally reactive systems to create sustainable energy solutions