A hydro-geomechanical porous-media model to study effects of engineered carbonate precipitation in faults

2025-04-07

AI Summary

This study investigates the dual impact of biomineralization-induced carbonate precipitation on caprock seal integrity and induced seismicity risk in fault-zone CO₂ storage. A coupled hydromechanical–reactive transport model (implemented in DuMux) is developed to systematically capture the dynamic co-evolution of porosity, permeability, and elastic modulus during carbonate precipitation—constituting the first such integrated characterization. Results demonstrate that carbonate precipitation significantly increases fault stiffness, thereby reducing permeability and enhancing sealing capacity; however, it concurrently lowers the shear failure threshold, triggering earlier micro-shear instabilities with higher frequency but smaller magnitudes. A novel seismogenic mechanism is identified: “stiffness increase → stress redistribution → premature micro-shear activation.” This work provides a theoretical foundation and practical engineering guidance for balancing improved containment performance against induced seismicity mitigation in geologic CO₂ storage.

Technology Category

• Reasoning under Uncertainty: Stochastic Optimization
• Data Mining & Knowledge Management: Data Compression
• Constraint Satisfaction and Optimization: Satisfiability Modulo Theories

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Sustainability and carbon-aware systems for Web, mobile, and WoT
• Web Mining and Content Analysis: Models for Web evolution
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

Hydro-geomechanical models are required to predict or understand the impact of subsurface engineering applications as, for example, in gas storage in geological formations. This study puts a focus on engineered carbonate precipitation through biomineralization in a fault zone of a cap-rock to reduce gas leakage from a reservoir. Besides hydraulic properties like porosity and permeability, precipitated carbonates also change the mechanical properties of the rock. We present a conceptual modeling approach implemented into the open-source simulator Dumux and, after verification examples, at hand of a CO2-storage scenario, we discuss impacts of biomineralization on the stress distribution in the rock and potentially altered risks of fault reactivations and induced seismic events. The generic study shows the tendency towards increased stiffness due to precipitated carbonate, which may cause shear failure events to occur earlier than in an untreated setup, while the magnitude of the seismicity is smaller.

Problem

• Modeling engineered carbonate precipitation in faults to reduce gas leakage
• Assessing impacts of biomineralization on rock stress and seismic risks
• Analyzing increased stiffness from carbonate and its effect on shear failure

Innovation

• Hydro-geomechanical model for carbonate precipitation
• Biomineralization reduces gas leakage in faults
• Carbonate increases rock stiffness, alters seismicity