EXPERIMENTAL RESEARCH OF FORMATION PROCESS OF METHANE HYDRATE IN FREEZING COARSE-GRAIN SAND BY COMPUTERIZED TOMOGRAPHY
冻结粗砂土中甲烷水合物形成CT试验研究

The experimental research of formation process of methane hydrate in frozen soil is very important to comprehend the formation and existing mechanisms of natural gas hydrate in frozen porous media,and also very meaningful to estimate the climate change and environment change in permafrost areas.The experimental research of formation process of methane gas hydrate in frozen coarse grain sand by computerized tomography(CT) is expatiated on in this article.It was proved in the experiment that CT could describe the formation process through the way of CT value which is closely related to the formation of methane hydrate,moisture migration and density change.The formation of methane hydrate can be observed by computation of CT images in different time,and the pressure would decrease evidently with the generating of phase transition heat in this process.The estimation of methane hydrate formed could be influenced by the absorption coefficient coarse grain sand because of its high density,but the other information,such as the changes of pressure and temperature,and CT image can be used to help to judge clearly the formation of methane hydrate in freezing coarse grain sand.