Halite precipitation during CO2 injection: insights from microfluidics and cores
L. Yan (TU Delft - Reservoir Engineering)
D. Voskov (TU Delft - Reservoir Engineering, Stanford University)
R. Farajzadeh (TU Delft - Reservoir Engineering, Shell Global Solutions International B.V.)
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Abstract
Halite precipitation during CO2 injection can significantly reduce injectivity and impact long-term storage in saline aquifers and depleted reservoirs. However, the impact of geological porous media on salt precipitation and brine movement is not fully undersood. This study explores salt precipitation dynamics from the pore to core scale using microfluidic experiments and core-flooding tests. Microfluidic results reveal three distinct phases of salt deposition: slow evaporation, rapid evaporation, and complete dry-out. Heterogeneous pore structures retain more initial water, leading to localized salt accumulation due to capillary effects. Core-scale experiments show that permeability strongly influences salt penetration and porosity reduction. In high-permeability cores, salt fronts extend deeper into the rock, causing up to 70% porosity reduction. In contrast, heterogeneous cores experience limited salt penetration but increased surface accumulation, suggesting that capillary pressure and brine redistribution control final deposition patterns. These findings highlight the complex interactions between fluid flow, rock properties, and salt crystallization, which provides valuable insights for predicting injectivity loss and optimizing CO2 storage strategies. Understanding these mechanisms is essential for improving reservoir management and ensuring the long-term stability of geological CO2 sequestration projects.