Linear stability and numerical analysis of gas hydrate dissociation in hydrate bearing sediments

Abstract

The stability of gas hydrate (GH) dissociation is crucial for understanding and predicting various hazards triggered by GH dissociation, such as landslides and gas blowouts. This study employs linear stability analysis and numerical simulation approaches to investigate the dynamics of GH dissociation under depressurization and heating. An instability criterion is derived, emphasizing conditions where the environmental heat supply exceeds the heat absorption by GH. We analyze the spatial and temporal evolution of key parameters, such as pore pressure, GH volume fraction, temperature, and strength, across different dissociation zones within the sediment. It is observed that pore pressure and temperature increase rapidly over time in unstable conditions, resulting in GH dissociation completing in approximately 10 s and a sharp decrease in the strength of hydrate-bearing sediments (HBS). Our findings offer insights into the behavior of HBS during GH dissociation and elucidate the formation mechanism of potential hazards associated with GH dissociation.