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 φ500 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. © All Rights Reserved.