Depressurization is an effective method to exploit natural gas hydrate reservoirs. However, ice might be formed due to the endothermic effect of hydrate dissociation, which will have a significant influence on gas production. In this work, a numerical model is established to investigate the hydrate dissociation performance by depressurization near the quadruple point. The impact of production pressure and intrinsic permeability on gas production and ice formation are also analyzed. It is revealed that the ice tends to be formed around the perforated interval due to the lower production pressure. A decrease in the effective porosity and permeability due to ice formation has been observed. But in fact, the formed ice has played a positive role in enhancing gas production owing to the released latent heat during ice formation. A large amount of ice is formed which results in a higher gas production rate when the production pressure is lower. The gas production rate and ice formation are greatly enhanced in the early production stage of a hydrate reservoir with a relatively high intrinsic permeability. For a hydrate reservoir with low permeability, ice formation is beneficial for gas production in the long term.

降压是开采天然气水合物储层的有效方法。但是，由于水合物分解的吸热作用而可能形成冰，这将对产气产生重大影响。在这项工作中，建立了一个数值模型来研究通过在四点附近进行降压来进行水合物分解的性能。还分析了生产压力和固有渗透率对天然气生产和结冰的影响。揭示出由于较低的生产压力，在穿孔间隔附近趋于形成冰。已经观察到由于冰的形成，有效孔隙率和渗透率降低了。但是实际上，由于在冰形成过程中释放出的潜热，形成的冰在提高气体产量方面发挥了积极作用。当生产压力较低时，会形成大量的冰，从而导致更高的气体生产率。在具有相对高的固有渗透率的水合物储层的早期生产阶段，气体生产率和冰的形成被大大提高。对于渗透率低的水合物储层，长期而言，结冰有利于天然气生产。