A Study on Simulating Dissociation Behavior in Methane Hydrate Deposits

近年来，日本近海的甲烷水合物被认为是非常规天然气资源。甲烷水合物矿床已在世界范围内被发现，包括在苏联、美国和加拿大的陆上，以及主要沿着北美和中美洲以及日本附近的大西洋和太平洋大陆架，如第二章所概述的甲烷水合物矿床的勘探区域和资源。该报告汇编了有关甲烷水合物资源的最新数据。作为最可能的值，世界上现有的甲烷水合物资源量估计为2，100万亿立方米<3>。其次，在一维模型中建立了预测甲烷水合物分解过程中甲烷气体和水的流动行为的数值模型。该模型由气液两相组成。它被认为是气体和水的流动，水合物的分解，和传热占主导地位的圆柱形一维多孔介质。对甲烷水合物的分解行为进行了模拟。所开发的模拟器对甲烷水合物分解产气过程的预测具有一定的参考价值。最后，对水合物饱和多孔介质渗透率变化进行了实验研究。在我们的初步研究实验中，我们使用正常冰作为伪水合物材料。结果表明，如第4章所示，随着固体饱和度的增加，布雷亚砂芯的渗透率急剧降低。

Recently, methane hydrates in offshore Japan are anticipated to be unconventional gas resources. The methane hydrate deposits have been identified worldwide both onshore in the USSR, the USA and Canada, and primarily along the Atlantic and Pacific continental shelf off north and central America and near Japan, as summarized in the second chapter as for prospecting areas and resources of methane hydrate deposits. This report compiled updated data on methane hydrate resources. As a most probable value, the methane hydrate resource in place is estimated to be 2,100 Trillion m^<3> in the World. Next, we constructed a numerical model for predicting flow behavior of methane gas and water under the methane hydrate dissociation in one-dimensional model. This model consists of two phases of gas and liquid. It is considered that flow of gas and water, hydrate dissociation, and heat transfer prevail in a cylindrical 1D porous medium. We tried simulation for behavior of methane hydrate dissociation. The developed simulator is useful to estimate of gas production process under the methane hydrate dissociation.Finally, We have done experimental work for the permeability change in a hydrate saturated porous medium. In our primary study, experiment, we used normal ice as pseudo-hydrate material. The results indicated a drastic reduction in the permeability of the Brea sand core with increased solid saturation as shown in the chapter 4.