The permeability of sediments is an important parameter that effects flow characteristics of the gas and water in the process of natural gas hydrates development. The distribution of gas hydrate is generally heterogeneous in porous media. It poses a great challenge to the permeability measurement of hydrate‐bearing sediments. To study the effect of heterogeneous distribution of methane hydrate on the permeability of porous media, methane hydrate formation in the sandstone and permeability measurement was carried out using a low‐field nuclear magnetic resonance (NMR) measurement system in situ conditions. The spatial distribution of methane hydrate in the core samples was determined by combining the T₂ distribution with magnetic resonance imaging. The results show that the distribution of methane hydrate is heterogeneous in the core samples. The temporal and spatial variation of permeability happens in the process of hydrate dissociation. The heterogeneity of methane hydrate distribution severely affects the analysis of permeability change. Considering the heterogeneity of methane hydrate distribution, a new method was proposed to obtain the quantitative relationship between hydrate saturation and relative permeability based on magnetic resonance imaging and the equivalent seepage capacity method. The results show that the relative permeability models obtained by this method agree better with experimental results. The optimum coefficients of relative permeability models obtained by equivalent seepage capacity method change significantly in contrast with the direct fitting method. The variation of the optimum coefficient is up to 300% in this study. The model coefficients are related to the pore characteristic of hydrate‐free porous media.

Natural gas hydrates in marine sediments undergo phase transitions under non-equilibrium conditions, making it challenging to accurately measure the permeability characteristics of hydrate-bearing sediments using experimental methods. In this study, pore network modeling is utilized to simulate the hydrate formation process and investigate the singlephase and two-phase permeability of hydrate-bearing sediments, and a comparative analysis was performed on consolidated and unconsolidated sediment samples. The results revealed the evolution of effective permeability as a function of hydrate saturation, and quantitative relationships were observed for the water retention curves and gas-water relative permeability, emphasizing the influence of pore structure and hydrate distribution on flow behavior. On the basis of the simulation results, predictive methods for irreducible water saturation, maximum water saturation, and key parameters in the van Genuchten and Brooks-Corey models for hydrate-bearing sediments are proposed. The findings provide deeper insights into gas-water flow dynamics in hydrate-bearing sediments and offer valuable guidance for hydrate resource exploitation, the assessment of environmental risks associated with hydrate dissociation, and the evaluation of carbon sequestration potential. Document Type: Original article Cited as: Zhang, Y., Liu, L., Luo, L., Ma, J., Ji, Y., Xiao, T., Wu, N. Permeability prediction in hydrate-bearing sediments via pore network modeling. Advances in Geo-Energy Research, 2025, 16(2): 158-170. https://doi.org/10.46690/ager.2025.05.07