Nature gas hydrates (NGHs) are regarded as a potential alternative energy source due to their huge reserves and wide distribution. According to the geophysical surveys, the pore-filling hydrates occupy a large proportion of the global hydrate reserves, especially for the marine regions. Therefore, with a novel pore-scale 3D morphological modeling algorithm, this study systematically studied the effect of the particle size on the physical characteristics of the pore-filling hydrate-bearing sediment (HBS). The pore system evaluations and permeability simulations were performed by utilizing pore network modeling (PNM), and the thermal and electrical simulations were conducted by utilizing a finite volume method (FVM). The results show that for the HBS with smaller particle size, the average radius of the pores and throats would also be reduced, and the fractal dimension of the pore system would be increased. In addition, with the increasing hydrate saturation, the fractal dimension of the pore system will increase firstly and then decrease. And these parameter evolutions could impact the physical properties correspondingly; specifically, the decreasing particle size in the HBS would reduce the permeability and electrical conductivity of HBS and enhance the apparent thermal conductivity of HBS.

中文翻译：

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粒度分布对充孔水合物沉积物物理特性的影响

天然气水合物（NGHs）储量大、分布广，被认为是一种潜在的替代能源。根据地球物理调查，填孔水合物占全球水合物储量的很大比例，尤其是在海洋地区。因此，本研究采用新型的孔隙尺度3D形态建模算法，系统地研究了粒径对孔隙填充水合物沉积物（HBS）物理特性的影响。孔隙系统评价和渗透率模拟采用孔隙网络模型（PNM）进行，热电模拟采用有限体积法（FVM）进行。结果表明，对于粒径较小的 HBS，孔喉平均半径也会减小，并且孔隙系统的分形维数会增加。此外，随着水合物饱和度的增加，孔隙系统的分形维数会先增大后减小。而这些参数的演变会相应地影响物理特性；具体而言，减小 HBS 中的粒径会降低 HBS 的渗透率和电导率，并提高 HBS 的表观热导率。