Enhancement of storage capacity of CO2 in megaporous saline aquifers using nanoparticle-stabilized CO2 foam

Abstract

Carbon dioxide sequestration in saline aquifers is a promising approach to reduce anthropogenic CO2 emissions and mitigate global climate change. CO2 storage capacity in aquifers depends on various factors such as interfacial tension, injection rate, viscosity ratio and characteristics of the porous media. We investigate the effects of these variables on CO2 gas and foam injection into a brine-saturated porous medium using a glass fabricated microfluidic device. The pore network is a representation of Washita-Fredericksburg formation located at a depth of 1110 m that is part of a saline aquifer located in southeast US and is currently under investigation to estimate its storage capacity as a commercial-scale CO2 storage hub. Contact angles and interfacial tensions between different fluids are measured under the experimental conditions. The three different injection rates are studied for each gaseous and foam injection. The displacement patterns images are captured by a high-resolution camera with an achromatic 60 M P sensor, and displacement performances are analyzed. CO2 foam injection appears to significantly increase CO2 storage in the microfluidic device (20%–40% higher compared to gas injection). Thus, CO2 foam injection is a promising approach to reduce CO2 mobility and enhance storage capacity in the target formation.