A study led by Professor Zhenyuan Yin from the Institute for Ocean Engineering, Tsinghua Shenzhen International Graduate School, Shenzhen, Guangdong, China, explores the path-dependent morphology of methane hydrates (MHs) and their dissociation using a high-pressure microfluidic system. The research investigates the phase change of methane hydrates and dynamic multiphase flow behavior at the pore scale, with applications in underground CO₂ sequestration and hydrogen storage for carbon neutrality. The study uses a novel high-pressure microfluidic chip and image analysis to directly visualize MH formation and dissociation. It reveals two MH formation mechanisms: (a) porous-type MH formed from gas bubbles at the gas-liquid interface, and (b) crystal-type MH formed from dissolved methane. The growth and movement of crystal-type MH can trigger the sudden nucleation of porous-type MH. MHs preferentially grow along the gas-liquid interface in pores. Dissociation under thermal stimulation generates gas bubbles with diameters of 20.0–200.0 μm. Three distinct stages of gas bubble evolution were identified: (a) single gas bubble growth, (b) rapid generation of gas bubble clusters, and (c) gas bubble coalescence. The study also examines the evolution of gas bubbles during MH dissociation, showing that the dissociation process involves the generation and coalescence of gas bubbles. The results provide direct visual evidence of MH growth in pores and insights into gas-liquid two-phase flow behavior during fluid production from natural gas hydrates (NGHs). The findings highlight the importance of understanding MH formation and dissociation mechanisms for effective production strategies from NGH reservoirs. The study's results contribute to the development of novel experimental techniques for visualizing MH growth and dissociation, enhancing understanding of the coupled thermal-hydraulic-mechanical-chemical (THMC) processes in MH systems.A study led by Professor Zhenyuan Yin from the Institute for Ocean Engineering, Tsinghua Shenzhen International Graduate School, Shenzhen, Guangdong, China, explores the path-dependent morphology of methane hydrates (MHs) and their dissociation using a high-pressure microfluidic system. The research investigates the phase change of methane hydrates and dynamic multiphase flow behavior at the pore scale, with applications in underground CO₂ sequestration and hydrogen storage for carbon neutrality. The study uses a novel high-pressure microfluidic chip and image analysis to directly visualize MH formation and dissociation. It reveals two MH formation mechanisms: (a) porous-type MH formed from gas bubbles at the gas-liquid interface, and (b) crystal-type MH formed from dissolved methane. The growth and movement of crystal-type MH can trigger the sudden nucleation of porous-type MH. MHs preferentially grow along the gas-liquid interface in pores. Dissociation under thermal stimulation generates gas bubbles with diameters of 20.0–200.0 μm. Three distinct stages of gas bubble evolution were identified: (a) single gas bubble growth, (b) rapid generation of gas bubble clusters, and (c) gas bubble coalescence. The study also examines the evolution of gas bubbles during MH dissociation, showing that the dissociation process involves the generation and coalescence of gas bubbles. The results provide direct visual evidence of MH growth in pores and insights into gas-liquid two-phase flow behavior during fluid production from natural gas hydrates (NGHs). The findings highlight the importance of understanding MH formation and dissociation mechanisms for effective production strategies from NGH reservoirs. The study's results contribute to the development of novel experimental techniques for visualizing MH growth and dissociation, enhancing understanding of the coupled thermal-hydraulic-mechanical-chemical (THMC) processes in MH systems.