A hydro-geomechanical porous-media model tostudy effects of engineered carbonateprecipitation in faults

Subsurface engineering applications, such as CO₂ storage, face critical challenges related to safety and sustainability, including induced seismicity and potential leakage pathways, particularly in fault zones. Biomineralization, specifically induced carbonate precipitation (ICP), offers a promising solution by transforming geological formations to reduce porosity and permeability while enhancing mechanical stability. A hydraulic-geomechanical model is essential to explore these effects.

We present a conceptual modeling approach using the open-source simulator Dumux, incorporating biomineralization effects on rock mechanics and fluid flow with minimal parameterization. The model is validated against benchmark problems, focusing on flow-geomechanics coupling and biomineralization implications. A reservoir-scale showcase is conducted, adapting a fault-reactivation scenario to investigate how biomineralization of leakage pathways impacts the reservoir's hydrogeomechanical behavior. Key considerations include sealing effects on stress states and altered failure patterns from continued fluid injection.

Simulation results show that biomineralization improves geomechanical and hydraulic properties, sealing flow paths to reduce porosity and permeability, with implications for underground gas storage. Gas injection induces stress changes consistent with field observations, although geological variability affects outcomes. Sealing fault zones increases stiffness and reduces deformation but creates uneven stress distribution, potentially leading to localized failures. Biomineralization reduces seismic activity compared to unsealed cases, though pressure buildup remains a concern due to delayed response times. The study emphasizes the site-specific nature of biomineralization, necessitating parameter validation, real-world data, and further exploration of diverse operational scenarios.