Kinetics of methane hydrate formation and dissociation in sand sediment

Le, Thi Xiu; Rodts, Stéphane; Hautemayou, David; Aimedieu, Patrick; Bornert, Michel; Chabot, Baptiste; Tang, Anh Minh

doi:10.1016/j.gete.2018.09.007

Cited by 24 publications

(21 citation statements)

References 39 publications

(26 reference statements)

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“…These observations confirmed the pore-filling/load-bearing distribution of MH in excess-water media (round MHs particles mixed with water in the pore space of porous media) that are being widely used for numerical simulations (Waite et al, 2004(Waite et al, & 2009. It is supposed that MH distribution at the grain scale of MHBS after the water saturation at low MH saturation and after the temperature cycle in the work of Le et al (2019Le et al ( & 2020 looks alike and resembles to natural MHBS.…”

Section: Discussionsupporting

confidence: 78%

“…That results in heterogeneous MH distributions at both pore and sample scales. Note that the excess-gas method is a common method used to create synthetic MHBS in laboratory for both macroscopic characterizations (Miyazaki et al, 2011a & b;Hyodo et al, 2013;Le et al, 2019;Le et al, 2020) and pore-scale observations by means of XRCT or SXRCT (Chaouachi et al, 2014;Lei et al, 2019a).…”

Section: Discussionmentioning

confidence: 99%

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An experimental investigation on methane hydrate morphologies and pore habits in sandy sediment using synchrotron X-ray computed tomography

Bornert

Aimedieu

et al. 2020

Marine and Petroleum Geology

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As pore-scale morphologies and spatial distribution (pore habits) of natural gas hydrates in marine sediments considerably affect their physical/mechanical properties, they have extensively been investigated by X-ray computed tomography (XRCT) and especially synchrotron X-Ray computed tomography (SXRCT). While both image spatial and scan temporal resolutions are being improved over time, it is still challenging to distinguish water from methane hydrate in an image due to their low absorption contrast. In this study, methane hydrate formation and growth in wet sand were observed at submicron/micron scale using SXRCT. Saline water (Potassium iodide -KI) was used in order to improve the image contrast. Evolutions of methane hydrate morphologies and distribution at both the pore and sample scales were observed. Results are discussed based on various mechanisms related to material behaviors and experimental conditions, e.g. suction variation during methane hydrate formation, local temperature gradient in the sample, and particularly the interaction of X-rays with the sample. Methane hydrate formation is interpreted as a dynamic process, favoring the Ostwald ripening. Furthermore, morphologies and pore habits of methane hydrates under excess-gas and excess-water conditions are discussed. Some recommendations are finally given for further studies on methane hydrates-bearing sediments via XRCT or SXRCT.

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Section: Discussionsupporting

confidence: 78%

Section: Discussionmentioning

confidence: 99%

An experimental investigation on methane hydrate morphologies and pore habits in sandy sediment using synchrotron X-ray computed tomography

Bornert

Aimedieu

et al. 2020

Marine and Petroleum Geology

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“…Multiple heating and cooling cycles were performed to increase hydrate saturation and improve hydrate distribution within sediments. Performing multiple heating/cooling cycles results in induced gas hydrate dissociation and reformation, which favors a more homogeneous gas hydrate distribution [70]. To study the CH 4 -CO 2 hydrate exchange, we first formed methane hydrate sediments in the presence of different chemicals in the water including SDS, L-methionine and 5 wt% methanol.…”

Section: Methane Hydrate Formation In Coarse Sedimentsmentioning

confidence: 99%

Enhanced CH4-CO2 Hydrate Swapping in the Presence of Low Dosage Methanol

et al. 2020

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CO2-rich gas injection into natural gas hydrate reservoirs is proposed as a carbon-neutral, novel technique to store CO2 while simultaneously producing CH4 gas from methane hydrate deposits without disturbing geological settings. This method is limited by the mass transport barrier created by hydrate film formation at the liquid–gas interface. The very low gas diffusivity through hydrate film formed at this interface causes low CO2 availability at the gas–hydrate interface, thus lowering the recovery and replacement efficiency during CH4-CO2 exchange. In a first-of-its-kind study, we have demonstrate the successful application of low dosage methanol to enhance gas storage and recovery and compare it with water and other surface-active kinetic promoters including SDS and L-methionine. Our study shows 40–80% CH4 recovery, 83–93% CO2 storage and 3–10% CH4-CO2 replacement efficiency in the presence of 5 wt% methanol, and further improvement in the swapping process due to a change in temperature from 1–4 °C is observed. We also discuss the influence of initial water saturation (30–66%), hydrate morphology (grain-coating and pore-filling) and hydrate surface area on the CH4-CO2 hydrate swapping. Very distinctive behavior in methane recovery caused by initial water saturation (above and below Swi = 0.35) and hydrate morphology is also discussed. Improved CO2 storage and methane recovery in the presence of methanol is attributed to its dual role as anti-agglomerate and thermodynamic driving force enhancer between CH4-CO2 hydrate phase boundaries when methanol is used at a low concentration (5 wt%). The findings of this study can be useful in exploring the usage of low dosage, bio-friendly, anti-agglomerate and hydrate inhibition compounds in improving CH4 recovery and storing CO2 in hydrate reservoirs without disturbing geological formation. To the best of the authors’ knowledge, this is the first experimental study to explore the novel application of an anti-agglomerate and hydrate inhibitor in low dosage to address the CO2 hydrate mass transfer barrier created at the gas–liquid interface to enhance CH4-CO2 hydrate exchange. Our study also highlights the importance of prior information about methane hydrate reservoirs, such as residual water saturation, degree of hydrate saturation and hydrate morphology, before applying the CH4-CO2 hydrate swapping technique.

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“…The evolution mechanism of the gas hydrate formation/ dissociation in porous media is associated with complex multiphase transition processes and uid movement/redistribution. [24][25][26] The conventional methods for investigating the kinetics of the hydrate formation/dissociation processes in laboratory usually deal with monitoring the measurable bulk properties such as the rate of changes in pressure, temperature and gas composition and reporting the apparent rate constants which may not fully represent the intrinsic kinetics. 20 Recently, the visualization techniques such as X-ray micro-CT and Magnetic Resonance Imaging (MRI) have been extensively employed to study the kinetics the hydrate formation/ dissociation in conjunction with the pore-scale associated phenomena, owing to their capability of both space and time resolution of the hydrate processes.…”

Section: Introductionmentioning

confidence: 99%

“…44,45 More recently, CH 4 formation behaviour was monitored by MRI to investigate water, gas and hydrate saturation and spatial distribution within mesoporous media. 26,33,46,47 Despite the substantial effect of the multiple thermal cycles on the properties of gas hydrate-bearing sediments, to the best of our knowledge, there is lack of in situ observation studies in this regard.…”

Section: Introductionmentioning

confidence: 99%