煤层中甲烷水合物存在可能性探讨

DISCUSSION ON THE POSSIBILITIES OF METHANE HYDRATE EXISTENCE IN COAL BED

之所以进行此项研究,就是力图使煤层气和瓦斯研究者重视煤层中甲烷水合物的存在,拓展煤层气或天然气水合物研究领域。为此,依据目前形成甲烷或天然气水合物的物质基础和温度压力的最新研究成果,结合煤层气形成及组成、含气煤层条件和煤的孔隙特征,探讨了煤层中甲烷水合物形成的可能性,并对煤层中甲烷水合物的相关问题进行了初步讨论。研究表明:①煤层中存在着甲烷水合物形成的物质、储存和温压条件;②煤的微孔结构和煤层气组成,特别是重烃组分有利于甲烷水合物在煤中的形成;③煤层中不仅存在着吸附态、游离态和溶解态甲烷,而且还存在着固态水合物甲烷;④煤层周围的岩层中也可能存在非常规天然气水合物。煤层气勘探开发和瓦斯防治过程中应重视煤层及其围岩中甲烷水合物的存在,对此还有大量的研究工作要做。

The discussion on existence of methane hydrate in coal-bed tends to persuade those researchers studying on methane and gas to think highly of the existence of methane hydrate in coal bed, and to expand their previous study on CBM and gas hydrate into a new area. Therefore, with analysis on CBM formation and compositions, and existing conditions of methane-bearing coal bed, and pore structure features of coal, it is discussed the existence of methane hydrate in coal bed and it was also primarily investigated some other issues on methane hydrate, based on the updating study on how the methane and gas hydrate formed under the condition including the substantial foundation, temperature and pressure, and so on. The discussion suggests that ①coal bed is provided with the material and deposit basis, and methane and gas hydrate can be formed under the condition of temperature and pressure; ②the microspore structure and its distribution of coal and CBM compositions, especially the heavy hydrocarbon; ③the methane can exist in coal beds not only in adsorbed state, free gas state, soluble state, but also in the state of solid hydrate; ④unconventional natural gas hydrate may be possible to exist in other rocks around the coal beds. The existence of methane and gas hydrate should be paid more attention to during the exploration and exploitation of CBM and the prevention and control of the mining-gas. However, there are still a lot of research works to be done with for the discussion.