Mechanisms of multiphase reactive flow using biogenically calcite-functionalized micromodels.

Area of Science:

• Geochemistry
• Subsurface Flow Dynamics
• Carbon Sequestration

Background:

• Dissolution of carbonate minerals is key to subsurface processes like geological carbon sequestration and karst formation.
• Carbonate reservoir reactivity poses risks to the integrity and security of sequestered carbon dioxide (CO2).

Purpose of the Study:

• To investigate pore-scale reactive transport dynamics in carbonate formations using a novel microfluidic device.
• To understand the impact of carbonate dissolution on geological CO2 storage security.

Main Methods:

• Development of a biogenically calcite-functionalized microvisual device.
• Observation and analysis of pore-scale reactive transport phenomena.
• Scaling results using nondimensional numbers.

Main Results:

• Discovery of a microscale mechanism where CO2 forms a protective phase, engulfing carbonate grains and limiting further dissolution.
• Identification of how this CO2 phase influences overall dissolution patterns.
• Demonstration of preferential leakage path formation.

Conclusions:

• The formation of a protective CO2 phase significantly impacts carbonate dissolution dynamics.
• Understanding these microscale mechanisms is vital for assessing and ensuring the security, safety, and capacity of industrial CO2 storage.