Experimental study on geochemical characteristic of methane hydrate formed in porous media  

作　　者：Qiang Chen Changling Liu Yuguang Ye 

机构地区：[1]Qingdao Institute of Marine Geology, the Ministry of Land and Resources, Qingdao 266071, Shandong, China [2]The key Laboratory of Marine Hydrocarbon Resources and Environment Resources, the Ministry of Land and Resources, Qingdao 266071, Shangdong, China

出　　处：《Journal of Natural Gas Chemistry》2009年第2期217-221,共5页天然气化学杂志（英文版）

基　　金：Supported by Natural Gas Hydrate in China Sea Exploration and Evaluation Project (G2H200200202);National Basic ResearchProgram of China (973 Program, Grant No. 2009CB219503)

摘　　要：The natural occurrence of methane hydrates in marine sediments has been intensively studied over the past decades, and geochemical charac-teristic of hydrate is one of the most attractive research fields. In this paper, we discussed the geochemical anomaly during hydrate formation in porous media. By doing so, we also investigated the temperature influence on hydrate formation under isobaric condition. It turns out that sub-cooling is an important factor to dominate hydrate formation. Larger subcooling provides more powerful driving force for hydrate formation. During the geochemical anomaly research, six kinds of ions and the total dissolved salt （TDS） were measured before and after the experiment in different porous media. The result is that all kinds of ionic concentration increased after hydrate formation which can be defined as salting out effect mainly affected by gas consumption. But the variation ratio of different ions is not equal. Ca^2＋ seems to be the most significantly influenced one, and its variation ratio is up to 80%. Finally, we theoretically made a model to calculate the TDS variation, the result is in good accordance with measured one, especially when gas consumption is large.The natural occurrence of methane hydrates in marine sediments has been intensively studied over the past decades, and geochemical charac-teristic of hydrate is one of the most attractive research fields. In this paper, we discussed the geochemical anomaly during hydrate formation in porous media. By doing so, we also investigated the temperature influence on hydrate formation under isobaric condition. It turns out that sub-cooling is an important factor to dominate hydrate formation. Larger subcooling provides more powerful driving force for hydrate formation. During the geochemical anomaly research, six kinds of ions and the total dissolved salt （TDS） were measured before and after the experiment in different porous media. The result is that all kinds of ionic concentration increased after hydrate formation which can be defined as salting out effect mainly affected by gas consumption. But the variation ratio of different ions is not equal. Ca^2＋ seems to be the most significantly influenced one, and its variation ratio is up to 80%. Finally, we theoretically made a model to calculate the TDS variation, the result is in good accordance with measured one, especially when gas consumption is large.

关 键 词：hydrate formation porous media SUBCOOLING salting out effect geochemical anomaly 

分 类 号：P618.51[天文地球—矿床学] TE642[天文地球—地质学]