Speaker
Description
Subsurface applications frequently involve the injection of fluids into the subsurface, which can result in mixing-induced mineral precipitation due to distinct geochemical properties of the injection fluid and ambient groundwater. In particular, during in situ carbon mineralization, the mixing of CO2-saturated solution with ambient groundwater can trigger the mineralization. This study investigates fluid mixing-induced mineral precipitation and their impact on permeability changes in fractured rock systems, with a focus on implications for carbon mineralization.
To simulate these processes, 3D-printed core samples and etched fractured rock cores were designed to mimic triple-porosity fractured basalt rocks. The use of 3D-printed core samples allowed for the efficient fabrication of controlled geometries. Sodium carbonate and calcium chloride solutions of equal concentrations (3 mM) were separately and simultaneously injected into the core samples to induce calcium carbonate precipitation through mixing. A confining pressure was applied to prevent fluid leakage along the outer surface of the core samples, while a pressure transducer continuously monitored differential pressure to track the progression of mineralization and permeability changes. The experiments were terminated when the pressure reached 200 psi. The results indicated spatially localized precipitation patterns, primarily concentrated within the etched channels, with limited mineral precipitation observed along fracture planes and in dead-end geometries. These findings demonstrate enhanced mineralization along preferential flow paths due to the enhanced fluid flux and mixing. Pressure measurements showed a gradual increase corresponding to fluid injection volumes, followed by a rapid rise towards the end of each experiment. These results provide the significance of mixing-induced precipitation in porous media, highlighting its potential impact on permeability and mineralization processes during carbon sequestration. The experiments were subsequently extended under varying flow rates using etched basalt core samples to better simulate reservoir conditions. X-ray micro-CT imaging and numerical modeling were performed to facilitate a comprehensive interpretation of the experimental results. The reproducible geometry of the core samples provided valuable insights into how flow rate and fracture geometry influence mixing-induced precipitation.
| Country | USA |
|---|---|
| Acceptance of the Terms & Conditions | Click here to agree |
