Microfluidic Investigation of Salt Precipitation and Hydrate during CO2 Injection
Abstract
Summary CO2 storage in depleted hydrocarbon reservoir and/or deep saline aquifers is an effective strategy for reducing greenhouse gas emission. However, the processes of halite precipitation and CO2 hydrate give the risk for the injectivity reduction. This study investigates the pore-scale impacts of salt precipitation and hydrate formation during CO2 injection into a porous domain by using glass-based microfluidics. We found that local heterogeneity of pore plays a critical role for precipitated salt distribution, patterns and water relocation driven by capillary forces. Heterogenous pore structures trap more water saturation than it in homogeneous ones, leading to significant difference in salt precipitation and pore blockage. In the hydrate microfluidic experiment, dynamics of hydrate formation and distribution are captured. Furthermore, various hydrate morphologies and stability states are directly observed. This work provides insights into the pore-scale dynamics of CO2 storage, emphasizing the need for a better understanding of the interactions among salt, hydrate and porous media.