多孔介质对天然气水合物形成的影响

Impact of porous medium on gas hydrate

（1.中国石油大学（华东），山东东营 257061；2.中国科学院广州天然气水合物研究中心，广东广州 510640；3.西南石油学院，四川成都 610500）

University of Petroleum, Dongying 257061, China

天然气水合物大量存在于海洋底部的淤泥多孔介质中，但多孔介质对天然气水合物形成过程的影响规律究竟如何，从理论和实验上进行了探讨。相平衡模型表明，多孔介质的表面张力作用使多孔介质毛细管中的气体-水合物-水达到三相平衡；对多孔介质和自由液面的相平衡影响因素分析表明，在相同浓度条件下，多孔介质中天然气水合物形成相平衡的温度更低，压力更高；对多孔介质和自由液面天然气水合物的实验分析表明，多孔介质对水合物的形成过程（天然气溶解阶段，水合物诱导阶段，水合物成长阶段）的影响程度不同，多孔介质缩短了水合物形成的诱导时间，在成长阶段较之自由液面生长的速率要快

There exists abundant gas hydrate in porous slurry medium at ocean bottom. Aiming at this issue, the impact of porous medium on forming process of gas hydrate is theoretically and experimentally researched. The phase equilibrium model shows that the surface tension in porous medium makes the gas-hydrate-water in capillaries keep three-phase equilibrium. The analysis of affecting factors on phase equilibrium between porous medium and free surface indicates that, in the same consistence, the temperature needed to form phase equilibrium is quite low while the pressure is high. The experiment of porous medium and free-surface gas hydrate suggests that the impaction degree of the porous medium on the forming process of the hydrate differs in different phases. The porous medium shortened the induction time, and so the growth rate at growing stage is faster than that of the free surface.