Abstract Marine methane hydrates have attracted global attentions as a considerable energy resource. The permeability of hydrate reservoirs critically affects the technical and economic feasibility of hydrate exploitation as well as the efficiency of gas production. In this study, marine sediments obtained from the South China Sea were used to remold core samples. Using a core holder, the gas permeability of marine sediments with and without methane hydrates were measured by injecting methane. In this study, the values of gas permeability range from 5.2 mD to 16.7 mD. The effects of confining pressure, hydrate saturation, and initial water saturation on gas permeability of cores were analyzed. The experimental results indicated that the gas permeability decreases (increases) with increasing (decreasing) confining pressure. In addition, the increase trend of confining pressure will significantly decrease on gas permeability in case the effective stress surpassed approximately 3.5 MPa. The deformation of silty-type marine sediments caused by increased confining pressure is irreversible to a certain extent. Relatively, the initial water saturation has little effect on gas permeability. This is attributed to that the water is bounded in the marine soil when the initial water saturation is less than 60%, resulting in a small water resistance effect. In addition, the hydrate dissociation induced by depressurization under confining pressure could result in a decrease of gas permeability. The results of this work revealed the effects of methane hydrates and confining pressure on the gas permeability of marine sediments, with great significance for the methane production from marine methane hydrate reservoirs.

中文翻译：

---

岩心保持器中含和不含甲烷水合物的海洋沉积物的气体渗透特性

摘要 海洋甲烷水合物作为一种重要的能源资源受到全球关注。水合物储层的渗透率严重影响水合物开采的技术经济可行性和采气效率。在这项研究中，从南海获得的海洋沉积物被用来改造岩心样品。使用岩心支架，通过注入甲烷测量有和没有甲烷水合物的海洋沉积物的气体渗透率。在这项研究中，气体渗透率值范围从 5.2 mD 到 16.7 mD。分析了围压、水合物饱和度和初始含水饱和度对岩心气体渗透率的影响。实验结果表明，气体渗透率随着围压的增加（降低）而降低（增加）。此外，当有效应力超过3.5 MPa左右时，围压的增加趋势将显着降低气体渗透率。围压增大引起的粉质型海相沉积物变形在一定程度上是不可逆的。相对而言，初始含水饱和度对气体渗透率影响不大。这归因于当初始含水饱和度小于 60% 时，水被束缚在海洋土壤中，导致水阻效应很小。此外，围压降压引起的水合物分解会导致气体渗透率降低。这项工作的结果揭示了甲烷水合物和围压对海洋沉积物气体渗透率的影响，