封闭系统中多孔介质甲烷水合物的CT实验研究

CT Experiment and Analyses of Methane Hydrate in Porous Media in Closed System

阐述了在封闭系统中的查理模型,建立了利用查理定律计算分析甲烷水合物生成和分解的方法。通过实验,对封闭系统中不同含水量多孔介质甲烷水合物生成、发育和分解的实验方法、相平衡条件、生成量关系等进行了探讨。在一定温度差的介质里,水分克服重力向冷端迁移并生成水合物。实验中利用查理数的改变计算水合物的生成量变化,连通性好的含水多孔介质有很好的水—气结合条件,达到平衡条件后迅速生成水合物,在240分钟内完成,含水量线性地影响甲烷水合物的生成量。同时,利用CT扫描方法直接观测含水粗砂在低温—高压环境下的甲烷水合物生成和分解过程,并可以利用CT图像数据计算出多孔介质中水分迁移、区域密度改变和砂体的移动、及分解后介质密度分布变化特征。

The Charles-model in closed system is discussed in this paper. The Charles-Law is used to calculate and analyze the formation and dissociation of gas hydrate. Through the experiment, the formation and dissociation process, development, equilibrium conditions and output forecast of methane hydrate of different water contents in porous media were discussed. In the media with temperature difference, the water, against the gravity, moved to the cold part to form the hydrate. In the experiment, the hydrate output was forecasted through the change of Charles-value and the hydrate would form quickly in 240 minutes when the equilibrium conditions were reached. And the water content affected the hydrate output linearly. At the same time, the formation and dissociation process of methane hydrate in low-temperature and high-pressure environment were observed by CT directly. By the CT images, the moisture migration in porous media, density changes, the movement of the media and the density distribution after dissociation could be obtained.