【作者】 叶陈诚；

【导师】 宋永臣；

【作者基本信息】 大连理工大学 ， 动力工程， 2012， 硕士

【摘要】 天然气水合物是未来最有潜力的新能源之一,在当今能源紧张污染严重的人类生存环境中。天然气水合物以其储量大,其副产物天然气燃烧清洁而广受好评。然而天然气水合物的工业成熟化的应用还没有成熟,如何安全开采,有效应用一直是各国科学家待解决的问题。如今,以经济性为特点的降压法开采开始走入科学家的视线。其对应的数值模拟方法也广受关注,对它们的研究具有重大的现实意义。本文应用黑油模型对天然气水合物管核建模,模拟其多孔介质中分解特性。对其进行敏感性分析,如压力,温度,水合物饱和度,模拟其在不同时间中的动态变化规律。并且,对天然气水合物的分解水相进行针对性的研究,讨论其对天然气水合物分解中的流动相(气和水两相)的流动,比较其中导热和对流传热的作用。在其流的过程中,本文也创新性地提出,应用达西修正式对气相流动进行更精确的模拟。为了水相对天然气水合物分解的影响特性,研究过程中模型通过改变甲烷水合物在多孔介质的核内的水相初始饱和度来观察水相流动特性,并分析所带来不同产气速率的原因。模拟结果展示了甲烷水合物分解前沿的变化规律与水相饱和度在此区域分布有关系。另一方面,通过比较甲烷气体饱和度在核内随时间的变化规律,和水相饱和度随时间变化率,研究在水合物分解过程中甲烷气体驱动水相的流动规律。通过数值模拟,本文主要完成了三方面工作。即：通过甲烷水合物降压分解过程研究水相敏感性分析；非饱和多孔介质中甲烷水合物分解过程中水相流动特性；为了提高模型对甲烷水合物流体流动变化趋势的准确性,将更适合甲烷水合物低温高压环境的Darcy-Forchheimer修正式代替经典的Darcy公式运用于数值模拟中。更多还原

【Abstract】 Gas hydrate is probably the most potential one of energy in the Future. Nowadays there is a lot of pollution coming from burning of fossil fuels; however, because of a huge reserve and clean tail gas, gas hydrate owns a good reputation. But the industry of gas hydrate is not very mature, how to get it efficiently and safely is an important problem to solve. Now exploiting gas hydrate by depressurize method is consider as an economical way by scientists. Meanwhile, the gas hydrate simulation is also developing fast, doing research about simulation is very important for the gas hydrate study work.In this paper, we used black-oil-type simulation model to describe the course of dissociation. The sensitivity analysis such as pressure, temperature and different phase saturation in different time are showed in the simulation. Besides, we also focused on the water phase change in the dissociation; we discussed the water and methane gas transfer; compare heat conduction and convection of heat transfer in the hydrate dissociation. In addition, we suggested used Darcy-Forchheimer law instead of classical Darcy law in the simulation to prove the accuracy of model result.In order to analyze the character of gas hydrate dissociation course, to study the water transfer by observing the change of water saturation in the core, to compare different result coming from different initial water saturation, we used simulation to reveal the relationship between the front dissociation area and water saturation distribution. On the other hand, our simulation result also showed the methane gas driving water course as the time passed. Then, we attempted to describe the gas and liquid two phase flow regulation among this experiment.Trough the simulator, we have mainly done three part work related to hydrate. They are water sensitivity analysis in the methane hydrate dissociation, water transfer character in the un-saturated media when hydrate decompose, and used Darcy-Forchheimer law instead of classical Darcy law to fit the special low temperature and high pressure environment.更多还原