<i>In Situ</i> Observation of Methane Hydrate Dissociation under Different Backpressures

Wang, Shenglong; Yang, Mingjun; Wang, Pengfei; Zhao, Yuechao; Song, Yongchen

doi:10.1021/acs.energyfuels.5b00486

Cited by 33 publications

(22 citation statements)

References 41 publications

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“…In the series of depressurization experiments, the MH was dissociated with a constant back-pressure of 2.6 MPa in Case 1. Similar results were found by other researchers 21,23,44 and the results in Cases 2 to 8, the data suggested that the hydrate dissociation process using depressurization method can be divided into two main stages, hydrate dissociation begins several minutes later aer back-pressure decreased due to hydrate reformation and ice generation forming blockages in the porous medium. 2.…”

Section: Analysis Of the Hydrate Dissociation Characteristicssupporting

confidence: 89%

Assessment of gas production from natural gas hydrate using depressurization, thermal stimulation and combined methods

Song

Zhang

et al. 2016

RSC Adv.

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The largest sources of hydrocarbons worldwide are distributed in the permafrost and submarine sediments in the form of methane hydrates, but exploitation of these hydrocarbons is still years away from being economical, safe, and commercially viable; thus, further research is needed. To analyze the characteristics of methane hydrate (MH) dissociation and evaluate the gas production during the application of different MH decomposition methods, this study firstly compared MH dissociation during depressurization, thermal stimulation, and combined method (depressurization + thermal stimulation) treatments using magnetic resonance imaging (MRI) in situ observation. In particular, the influences of back-pressure and temperature on hydrate dissociation, the hydrate saturation, the rate of hydrate dissociation and MRI images from each of the three methods were investigated. The results proved that during application of the depressurization and combined methods at different back-pressures (2.2-2.6 MPa), the MH dissociation proceeded via radial dissociation rather than axial dissociation; moreover, during the application of the thermal stimulation method at different dissociation temperatures (278.15-288.15 K), the MH dissociated uniformly. Overall, a combination of depressurization and thermal stimulation at the initial stage of hydrate decomposition was proposed and comparison of the three methods demonstrated that the combined method had obvious advantages for methane treatment.Specifically, the combined method was capable of solving the problems related to low gas production and poor energy efficiency that were encountered when using either the depressurization or thermal stimulation method alone.

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Section: Analysis Of the Hydrate Dissociation Characteristicssupporting

confidence: 89%

Assessment of gas production from natural gas hydrate using depressurization, thermal stimulation and combined methods

Song

Zhang

et al. 2016

RSC Adv.

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“…They are effective methods to determine the water content in porous media using the cumulative amplitude of T 2 distribution (Ge et al, ; Kleinberg et al, ) and the signal intensity of magnetic resonance image (Wang et al, ; Zhao et al, ). In this study, both ends of the core sample were connect with bulk water during the permeability measurement.…”

Section: Methodsmentioning

confidence: 99%

“…image (Wang et al, 2015;Zhao et al, 2015). In this study, both ends of the core sample were connect with bulk water during the permeability measurement.…”

Section: Journal Of Geophysical Research: Solid Earthmentioning

confidence: 99%

Study on the Effects of Heterogeneous Distribution of Methane Hydrate on Permeability of Porous Media Using Low‐Field NMR Technique

Hou

Zhao

et al. 2020

JGR Solid Earth

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The permeability of sediments is an important parameter that effects flow characteristics of the gas and water in the process of natural gas hydrates development. The distribution of gas hydrate is generally heterogeneous in porous media. It poses a great challenge to the permeability measurement of hydrate‐bearing sediments. To study the effect of heterogeneous distribution of methane hydrate on the permeability of porous media, methane hydrate formation in the sandstone and permeability measurement was carried out using a low‐field nuclear magnetic resonance (NMR) measurement system in situ conditions. The spatial distribution of methane hydrate in the core samples was determined by combining the T2 distribution with magnetic resonance imaging. The results show that the distribution of methane hydrate is heterogeneous in the core samples. The temporal and spatial variation of permeability happens in the process of hydrate dissociation. The heterogeneity of methane hydrate distribution severely affects the analysis of permeability change. Considering the heterogeneity of methane hydrate distribution, a new method was proposed to obtain the quantitative relationship between hydrate saturation and relative permeability based on magnetic resonance imaging and the equivalent seepage capacity method. The results show that the relative permeability models obtained by this method agree better with experimental results. The optimum coefficients of relative permeability models obtained by equivalent seepage capacity method change significantly in contrast with the direct fitting method. The variation of the optimum coefficient is up to 300% in this study. The model coefficients are related to the pore characteristic of hydrate‐free porous media.

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“…For bulk MH characterization, techniques like magnetic resonance imaging (MRI) [102,103] are applicable, that can map 1 H non-invasively with a three-dimensional resolution. 1 H MRI produces images of hydrogen contained in liquids, but not in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 methane and solids like ice or MH because of their much shorter transverse relaxation times (T2) which produce a high contrast.…”

Section: Experimental Characterizationmentioning

confidence: 99%

Methane Hydrate in Confined Spaces: An Alternative Storage System

2018

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Methane hydrate inheres the great potential to be a nature-inspired alternative for chemical energy storage, as it allows to store large amounts of methane in a dense solid phase. The embedment of methane hydrate in the confined environment of porous materials can be capitalized for potential applications as its physicochemical properties, such as the formation kinetics or pressure and temperature stability, are significantly changed compared to the bulk system. We review this topic from a materials scientific perspective by considering porous carbons, silica, clays, zeolites, and polymers as host structures for methane hydrate formation. We discuss the contribution of advanced characterization techniques and theoretical simulations towards the elucidation of the methane hydrate formation and dissociation process within the confined space. We outline the scientific challenges this system is currently facing and look on possible future applications for this technology.

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In Situ Observation of Methane Hydrate Dissociation under Different Backpressures

Cited by 33 publications

References 41 publications

Assessment of gas production from natural gas hydrate using depressurization, thermal stimulation and combined methods

Assessment of gas production from natural gas hydrate using depressurization, thermal stimulation and combined methods

Study on the Effects of Heterogeneous Distribution of Methane Hydrate on Permeability of Porous Media Using Low‐Field NMR Technique

Methane Hydrate in Confined Spaces: An Alternative Storage System

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