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论文类型：期刊论文

发表时间：2016-02-15

发表刊物：FUEL

收录刊物：SCIE、EI

卷号：166

页面范围：419-426

ISSN号：0016-2361

关键字：Natural gas hydrate; Depressurization; Methane gas recovery; Porous media

摘要：Natural gas hydrates (NGHs) are a promising energy source with huge reserves. The dissociation characteristics of NGHs need to be clarified further for developing safe and efficient technology for its recovery. In this study, Classes 1 and 2 NGH deposits were simulated by forming methane hydrate (MH) in porous media, and MH dissociation induced by depressurization was investigated using magnetic resonance imaging (MRI). MRI showed the liquid water distribution, which was used to analyze MH formation and dissociation. The vessel pressure was also measured during the experiments, which was compared with the MRI mean intensity of liquid water. MH dissociation processes were measured and analyzed under different backpressures, from 2.2 to 2.8 MPa. It was observed that liquid water hindered methane gas output during gas production; hydrate dissociation caused the movement of some liquid water, which usually led to fluctuations in MRI signal intensity. The experimental results also indicated that the MH dissociation pattern was affected by heat transfer; although a larger depressurization range led to faster dissociation, the average dissociation rate was controlled by heat transfer. (C) 2015 Published by Elsevier Ltd.