Dynamic Electrical Properties of Hydrate during Dissociation: New Insights from Multiphysics Coupling Simulation

Since natural gas hydrate is stable only under low-temperature and high-pressure conditions, it will dissociate and transform from a solid to gas state once conditions vary in the course of exploitation, and the massive release of methane gas will lead to the greenhouse effect. Characterizing the dynamic electrical properties during hydrate dissociation presents fundamental challenges, particularly with regard to time-dependent mechanisms. This study investigates marine hydrate-bearing sediments through pore-scale finite element modeling, coupling thermal and electrical fields to dynamically simulate phase transition processes. The constructed three-dimensional framework accounts for diverse hydrate distribution patterns and saturation levels during dissociation. The results show that resistivity decreases gradually with temperature changes and hydrate phase transition. According to the temperature change caused by heat conduction, the hydrate dissociation process can be divided into three stages. Moreover, the variation in saturation during the hydrate phase transition affects the speed of resistivity variation but does not change the trend of that. It is also found that the trend of hydrate dissociation with time is similar for different distribution morphologies. This study enhances the understanding of coupled thermoelectrical responses in hydrate-bearing sediments under dynamic dissociation conditions and provides insight into the electrical properties of hydrate-bearing sediments with phase transition and shows potential application value in the exploitation of natural gas hydrate.