降压开采模拟试验的水合物分解阵面演化过程

水合物分解阵面演化过程与开采安全性和产气效率密切相关,是开采原位监测的重要组成部分。在玻璃砂样品中进行了甲烷水合物降压开采模拟试验,探讨了水合物饱和度对渗流阵面和水合物分解阵面演化过程的影响,结合已有理论模型,分析了水合物分解阵面传播速度的关键影响因素。结果表明:渗流阵面和水合物分解阵面的传播距离均与时间平方根呈近似线性关系,传播速度均随水合物饱和度的增加而减小;水合物分解阵面的传播速度随多孔介质的有效渗透率和降压幅度的增加而变快,随孔隙率的增加而变慢,粗砂质地层更有利于水合物降压分解阵面的传播。

On the Hydrate Dissociation front Evolution in Simulation Experiment of Depressurization Mining

Hydrate dissociation front evolution is closely related to mining safety and gas production efficiency, is the important part of mining in-situ monitoring. Simulation experiment of methane hydrate depressurization mining was conducted for glass sand sediment samples. The influence of hydrate saturation on the seepage front and hydrate dissociation front evolution was explored. Combining with existing theoretical model, key factors to hydrate dissociation front propagation velocity was analyzed. Experimental results show that the propagation distance of seepage front and hydrate dissociation front is approximately linearly associated with square root of time, respectively. Both front propagation velocities decrease with the increase of hydrate saturation. The propagation velocity of hydrate dissociation front increases with the increase of porous media effective permeability and depressurization amplitude and decreases with the increase of porosity. Texture of coarse sand layer is more conducive to the propagation of hydrate depressurization dissociation front.