Effects of Halogen Ions on Phase Equilibrium of Methane Hydrate in Porous Media

Yang, Mingjun; Song, Yongchen; Liu, Yu; Lam, Wei-Haur; Li, Qingping; Yu, Xilong

doi:10.1007/s10765-012-1191-3

Cited by 14 publications

(4 citation statements)

References 38 publications

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“…In the past 20 years, researchers have conducted many studies on the hydrate phase equilibrium and reaction kinetics in porous media. − However, to date, the effect of porous media on hydrate thermodynamic and kinetic characteristics still is not clear. In 2015, Zang et al reported that one of the key factors causing this issue was the lack of explicit classification of porous media .…”

Section: Introductionmentioning

confidence: 99%

Reaction Kinetic Characteristics and Model of Methane Hydrate Formation in Porous Media

Zhang

et al. 2017

Energy Fuels

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Most of the natural gas hydrates on Earth are buried in shallow formations under deep water. Comprehensively understanding the reaction kinetic characteristics of gas hydrate in porous media is very beneficial to the deep exploration of the hydrate accumulation in nature. In this paper, the formation process of CH4 hydrate in porous media was simulated physically, using a reactor that is operating at high pressure and low temperature. The hydrate phase equilibrium and reaction kinetic characteristics at different temperatures, pressures, sand grain sizes, and clay contents were assessed. Based on the determination of relevant hydrate kinetic parameters, a novel mixing-flux hydrate reaction model was proposed, which can be used for numerical simulation of gas hydrate accumulation. The experimental results show that the porous media can make the phase equilibrium of CH4 hydrate shift to the right under the capillary effects on the gas and hydrate phases. Low temperature and high pressure can provide a large driving force for hydrate formation, but large clay content and small sand grain size usually give a negative effect on the CH4 transfer in the porous media. It often leads to a slow hydrate formation rate and hard distinction of pressure drop between hydrate nucleation and growth stages. Based on the experimental results, the hydrate nucleation kinetic parameters were regressed, and the activation energy (E a), as well as the reaction frequency factor (k fo), of hydrate growth were fitted to be 75.45–90.85 kJ/mol and 8.72 × 108–6.02 × 1011 mol/(m2 kPa day), respectively. In the numerical simulation of hydrate accumulation, the hydrate formation process can be described by coupling the low-flux reaction and the high-flux reaction, which consume the CH4 dissolved in water and the free CH4 gas in pores, respectively. This novel mixing-flux hydrate formation model is suitable for the flexible and practical hydrate accumulation simulation, which can consider various gas sources and transfer states in the hydrate reservoir.

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Section: Introductionmentioning

confidence: 99%

Reaction Kinetic Characteristics and Model of Methane Hydrate Formation in Porous Media

Zhang

et al. 2017

Energy Fuels

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“…The detailed procedure can be found in our previous publications . The isochoric method was used to measure the hydrate phase equilibrium conditions, which means the experiments were processed in a constant volume, and there was no mass transfer between the vessel and the environment during the hydrate formation and dissociation process.…”

Section: Methodsmentioning

confidence: 99%

Hydrate phase equilibrium for CH₄‐CO₂‐H₂O system in porous media

et al. 2016

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CO2/CH4 replacement in hydrate exploitation is considered a promising method to enhance natural gas production and mitigate the greenhouse effect. Since the gas concentration in mining hydrate sediment changes with the displacement process, it is crucial to investigate the hydrate formation and dissociation characteristics with the presence of different gas mixtures. To obtain fundamental thermodynamic data, CO2/CH4 gas mixture hydrate phase equilibrium conditions in porous media were experimentally investigated. The experiments were conducted at 276.55–284.85 K and 2.10–6.80 MPa using an isochoric method with different CO2/CH4 gas mixture compositions (CO2 mole fractions were 0.798, 0.499, and 0.199 mol/mol (79.8, 49.9, and 19.9 mol%)). The results showed that gas mixtures with higher CO2 mole fractions had lower hydrate equilibrium pressure (p) under the same temperature (T) according to the experimental data. The two different porous media used in the experiments had a slight influence on gas mixture hydrate phase equilibrium conditions. An improved thermodynamic model was proposed to calculate the CO2/CH4 hydrate phase equilibrium conditions in porous media, and the prediction results fitted closely to the experimental data.

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“…In this study, we used the ionic composition of Tishchenko et al (2005) to calculate the maximum salinity curve, which differed substantially from that of the Nankai Trough (Strasser et al, 2014). The inhibitory effect of different ions on hydrate generation varied (Chong et al, 2017), and the accuracy of the results could be improved by considering the influence on phase equilibrium conditions of low ion concentrations (Yang et al, 2012).…”

Section: Effectiveness Of the Salt Inhibitionmentioning

confidence: 99%

Simulation of methane hydrate formation in coarse‐ to fine‐grained sediments in the Nankai Trough, Japan

Xu,

Tomaru

2023

Island Arc

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The properties of host sediments and pore water considerably affect both the occurrence and formation processes of methane hydrate. In coarse‐grained layers, hydrates are generally concentrated preferentially in the pore space, and their formation is influenced by pore water salinity. To understand how geophysical and geochemical factors control the distribution of methane hydrates, we conducted numerical simulations using a one‐dimensional flow model under different reservoir and fluid conditions in the Kumano Forearc Basin, Nankai Trough, Japan. Assuming an estimated range of methane flux between 0.002 and 1.9 kg m−2 year−1, three flow scenarios were considered. When the methane flux was relatively small, the results coincided with the observed hydrate distribution. In general, a low‐methane flux decreases the hydrate saturation upward from the bottom of the methane hydrate stability, whereas a high‐methane flux increases the saturation downward. These results also suggest that the sediment structure, such as the fracture distribution, influences the sediment stress conditions and constrains the flow regime. We further examined the effects of permeability changes in the heterogeneous lithological units on the simulation results using typical permeabilities of 10−13 m2 for sand and 10−15 m2 for mud. The results showed that hydrate saturation sharply increased and decreased in adjacent high‐ and low‐permeability units, respectively. The consideration of complex stratigraphic conditions and variable fluid configurations provides an understanding of the environmental factors controlling hydrate generation and distribution, which is important for hydrate resource extraction and geohazard prevention.

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Effects of Halogen Ions on Phase Equilibrium of Methane Hydrate in Porous Media

Cited by 14 publications

References 38 publications

Reaction Kinetic Characteristics and Model of Methane Hydrate Formation in Porous Media

Reaction Kinetic Characteristics and Model of Methane Hydrate Formation in Porous Media

Hydrate phase equilibrium for CH₄‐CO₂‐H₂O system in porous media

Simulation of methane hydrate formation in coarse‐ to fine‐grained sediments in the Nankai Trough, Japan

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Effects of Halogen Ions on Phase Equilibrium of Methane Hydrate in Porous Media

Cited by 14 publications

References 38 publications

Reaction Kinetic Characteristics and Model of Methane Hydrate Formation in Porous Media

Reaction Kinetic Characteristics and Model of Methane Hydrate Formation in Porous Media

Hydrate phase equilibrium for CH4‐CO2‐H2O system in porous media

Simulation of methane hydrate formation in coarse‐ to fine‐grained sediments in the Nankai Trough, Japan

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Hydrate phase equilibrium for CH₄‐CO₂‐H₂O system in porous media