Examination of Hydrate Formation Methods: Trying to Create Representative Samples

Kneafsey, Timothy J.; Rees, E. V.; Nakagawa, Seiji; Kwon, Tae‐Hyuk

doi:10.2172/1050730

Cited by 17 publications

(9 citation statements)

References 12 publications

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“…Later, Falser et al [65] used this method to produce artificial HBS samples for the numerical simulation of dissociation experiments, but they used the average value of SH = 40% without considering spatial heterogeneity. The experimental study of Kneafey et al [79] used X-ray CT scanning to show that heterogeneities in the SH of hydrates formed in porous media depended on the location of the trapped gas. In recent studies, Yang et al [80], [81], [82] used the Magnetic Resonance Imaging (MRI) technique to compare the water saturation (SA) distributions of HBS formed by both the excess-gas and the excess-water methods, and revealed consistently heterogeneous SA (and, by inference, heterogeneous SH) distributions.…”

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confidence: 99%

Numerical analysis of experimental studies of methane hydrate formation in a sandy porous medium

et al. 2018

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Highlights • MH formation via excess-water method was numerically analyzed using T+H v1.5. • MH formation is determined as a kinetic reaction with dominant thermal processes controlling MH formation. • Flow, thermal, and kinetic rate parameters are optimized using a historymatching technique. • The spatial distributions of various phases at the end of the MH formation are strongly heterogeneous.

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confidence: 99%

Numerical analysis of experimental studies of methane hydrate formation in a sandy porous medium

et al. 2018

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“…Thus, synthesizing hydrates from ''dissolved-gas method'' often uses water-soluble proxy, such as carbon dioxide [Tohidi et al, 2001;Katsuki et al, 2006] or tedrahydrofuran [Lee et al, 2007;Yun et al, 2007]. A mix of free gas bubbles and water, whose interfaces are considered as preferential hydrate nucleation sites in marine sediments, can be established with ''excess-water method'' by water injection into the gas-saturated dry porous media [Yang et al, 2008;Priest et al, 2009], but difficulties still remain in achieving uniform distribution of water in the media [Kneafsey et al, 2010].…”

Section: Geochemistry Geophysics Geosystemsmentioning

confidence: 99%

Laboratory formation of noncementing hydrates in sandy sediments

Choi

Dai

Cha

et al. 2014

Geochem. Geophys. Geosyst.

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Natural hydrate-bearing sediment (HBS) predominantly exists in noncementing habit, and its limited availability for use in laboratory studies demands a time-effective and repeatable laboratory process for forming representative samples with natural accumulation habit. This study reports on a three-step laboratory process for forming noncementing methane hydrate in sandy sediments: (1) initial HBS formation under excess-gas conditions; (2) slow saline water (5 wt % CaCl 2 ) injection under strictly controlled pressure-temperature (P-T) conditions; and (3) a temperature warming/cooling cycle. Changes in compressional wave velocity (V p ) of sediment, as well as P-T condition, were monitored throughout the tests. The evolution of V p , in good agreement with rock physics model calculations, suggested that the transition from cementing hydrate into noncementing hydrate occurs during saline injection as well as temperature warming/cooling cycle. The proposed process appeared to be an efficient and consistent substitute for the existing methods, to form noncementing hydrate habit in sandy sediments.

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“…But the extent of these behavioral changes depends on hydrate accumulation habits and the degree of hydrate saturation. The volume fraction and spatial distribution of the hydrate phase, in turn, depend on the natural environment for an in situ sample or on how a synthetic sample is prepared in the laboratory . Three hydrate accumulation habits from rock physics have been widely cited and include pore filling , load bearing, and cementing as illustrated in Figure .…”

Section: Introductionmentioning

confidence: 99%

An SMP critical state model for methane hydrate‐bearing sands

Lin

Seol

Choi

2015

Num Anal Meth Geomechanics

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Summary Mechanical properties of methane hydrate‐bearing soils are complex. Their behavior undergoes a significant change when hydrates dissociate and become methane gas. On the other hand, methane hydrates are ice‐like compounds and, depending on the hydrate accumulation habits and the degree of hydrate saturation, may cement soil particles into stronger and stiffer soils. A new constitutive model is proposed that is capable of capturing essential characteristics of hydrate‐bearing soils. The core of the model includes the spatial mobilized plane concept; a transformed stress, tij; the critical state; and the subloading framework. The proposed model gives soil responses due to stress changes or hydrate saturation changes or both. The performance of the model has been found satisfactory, over a range of hydrate saturation and confining pressures, using triaxial test data from laboratory‐synthesized samples and from field samples extracted from Nankai Trough, Japan. Copyright © 2015 John Wiley & Sons, Ltd.

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Examination of Hydrate Formation Methods: Trying to Create Representative Samples

Cited by 17 publications

References 12 publications

Numerical analysis of experimental studies of methane hydrate formation in a sandy porous medium

Numerical analysis of experimental studies of methane hydrate formation in a sandy porous medium

Laboratory formation of noncementing hydrates in sandy sediments

An SMP critical state model for methane hydrate‐bearing sands

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