石英砂中甲烷溶解运移体系水合物生成与聚集实验分析

建立了可模拟海底天然气水合物形成环境的大型三维成藏实验模拟装置，其主体高压反应釜内径500 mm，高1000 mm。在此基础上，采用填砂模型，进行了甲烷溶解运移体系下甲烷水合物生成与聚集过程的实验模拟分析。实验流程为：甲烷溶解于NaCl溶液中，再泵送进入高压反应釜，在沉积层中渗流并生成甲烷水合物。通过30个电阻率传感器监测甲烷水合物的生成和聚集过程。实验结果表明，甲烷溶解运移体系下甲烷水合物生成之后首先分散在溶液中，当溶液的总甲烷浓度（溶解的甲烷及水合物分散相中的甲烷）达到操作条件下盐溶液体系甲烷饱和溶解度后，甲烷水合物从溶液中析出。电阻率分布实验结果表明，析出甲烷水合物的聚集区域受溶液流动控制。

Experimental investigation on formation and accumulation of hydrate in quartz sand and methane-dissolved seeping system

In order to investigate the formation behavior of methane hydrate, a large three-dimensional physical simulation device with a high pressure vessel of Ø500 mm×1000 mm was designed and built to experimentally simulate the formation and accumulation of natural gas hydrate in natural environment. Using this apparatus, the formation and accumulation process of hydrate in quartz sand from methane-dissolved seeping system was experimentally studied. Methane was first dissolved in brine, and pumped into the high pressure vessel, then seeped into sediment and formed hydrate. The whole hydrate formation and accumulation process was tracked down by 30 sensors of electrical resistivity. The experimental results showed that for methane-dissolved seeping system, the formed hydrate first dispersed into the solution. After the total methane concentration (methane in solution and hydrate) is higher than methane solubility under liquid-vapor equilibrium condition, the hydrate will precipitate from solution. The distribution data of electrical resistivity indicated that the accumulation region of hydrate is limited by the fluid seeping behavior.