Impact of multiphasic pore-scale interactions on gas hydrate formation and dissociation characteristics and kinetics: a microfluidic study

Understanding the multiphasic interactions governing gas hydrate formation and dissociation is critical for optimizing natural gas storage and extraction. This study investigates the characteristics and kinetics of methane hydrate formation and dissociation within porous media using a microfluidic chip platform designed to simulate natural conditions. By introducing methylene blue for enhanced phase differentiation, five distinct hydrate morphologies-block, vein, point, membrane, and shell-were identified. These morphologies were strongly influenced by multiphasic interactions involving water, gas, and solid phases. Block and vein hydrates predominantly formed in water-saturated pores, while point and membrane hydrates appeared as coatings associated with gas migration. Shell hydrates emerged post-gas relocation, filling pore spaces. During dissociation, free gas presence significantly accelerated the dissociation process, achieving rates approximately 12 times faster than in water-only systems. Gas migration played a pivotal role in hydrate fragmentation and dissociation kinetics. These findings deepen our understanding of gas hydrate behavior under multiphasic conditions, offering valuable insights for enhancing natural gas storage and extraction.