Analysis of Hydrate Heterogeneous Distribution Effects on Mechanical Characteristics of Hydrate-Bearing Sediments

It is reported that hydrate distributes inhomogeneously in synthesized gas hydrate-bearing sediments (GHBS). To investigate the effect of hydrate distribution heterogeneity on the mechanical characteristics of the hydrate-bearing sediments, we modeled the specimens with uniform hydrate saturation but different hydrate distributions and simulated the triaxial compression test process of the specimens using discrete element method (DEM). The hydrate particles were randomly inserted into the specified intergranular void space as in layered pore-filling mode to simulate the heterogeneous distribution. The analyses of the simulation results, including stress-strain curves and volumetric responses, indicated that the heterogeneity of hydrate distribution has great impacts on the mechanical parameters of hydrate-bearing sediments, including the elastics modulus, shear strength, and dilation. The anisotropy of the hydrate heterogeneous distribution effect is also observed. The difference of mechanical properties among the specimens with different hydrate distributions can reach over 15%, which is already comparative to the difference between the hydrate-bearing specimen and the one with twice its hydrate saturation. According to the findings of this work, the effect of hydrate heterogeneous distribution is required to be considered while characterizing the mechanical properties of GHBS.

Automated summary

The study showed that the heterogeneity of hydrate distribution significantly affects the mechanical parameters of hydrate-bearing sediments, including elastic modulus, shear strength, and dilation. Anisotropy of the hydrate heterogeneous distribution effect was also observed. Considering the impact of hydrate distribution heterogeneity is essential when characterizing the mechanical properties of GHBS.