Formation and Dissociation of Tetrahydrofuran Hydrate in Porous Media

2010 ◽  
Author(s):  
Lei Yao ◽  
Jiafei Zhao ◽  
Chuanxiao Cheng ◽  
Yu Liu ◽  
Yongchen Song
Keyword(s):  
Porous Media ◽  
Pore Size ◽  
Formation Rate ◽  
Hydrate Formation ◽  
Dissociation Rate ◽  
Glass Beads ◽  
Experimental Result ◽  
Adjacent Area ◽  
Sample Container ◽  
Hydrate Saturation

Tetrahydrofuran hydrate has long been used as a proxy of methane hydrate in laboratory studies. This paper investigates the formation and dissociation characters of tetrahydrofuran hydrate in porous media using the magnetic resonance imaging (MRI) technology. Various sized quartz glass beads are used to simulate the sediment. The formation and dissociation processes of THF hydrate are observed. The hydrate saturation during the formation is calculated based on the MRI data. The experimental result indicates that the third surface has an important effect on hydrate formation process. THF hydrate crystals begin to form on the glass beads and in their adjacent area as well as from the wall of the sample container. Furthermore, as the pore size increases, or the formation temperature decreases, the formation rate of THF hydrate gets faster. However, the dissociation rate is mostly dependent on the dissociation temperature rather than the pore size.

scholarly journals Maximum Sizes of Fluid-Occupied Pores within Hydrate-Bearing Porous Media Composed of Different Host Particles

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Lele Liu ◽  
Nengyou Wu ◽  
Changling Liu ◽  
Qingguo Meng ◽  
Haitao Tian ◽  
...  
Keyword(s):  
Porous Media ◽  
Fractal Theory ◽  
Hydrate Formation ◽  
Maximum Size ◽  
Theoretical Models ◽  
Equivalent Diameter ◽  
Pore Filling ◽  
Particle Properties ◽  
Hydrate Saturation ◽  
Hydrate Bearing Sediments

Hydraulic properties of hydrate-bearing sediments are largely affected by the maximum size of pores occupied by fluids. However, effects of host particle properties on the maximum size of fluid-occupied pores within hydrate-bearing sediments remain elusive, and differences in the maximum equivalent, incircle, and hydraulic diameters of fluid-occupied pores evolving with hydrate saturation have not been well understood. In this study, numerical simulations of grain-coating and pore-filling hydrate nucleation and growth within different artificial porous media are performed to quantify the maximum equivalent, incircle, and hydraulic diameters of fluid-occupied pores during hydrate formation, and how maximum diameters of fluid-occupied pores change with hydrate saturation is analyzed. Then, theoretical models of geometry factors for incircle and hydraulic diameters are proposed based on fractal theory, and variations of fluid-occupied pore shapes during hydrate formation are discussed. Results show that host particle properties have obvious effects on the intrinsic maximum diameters of fluid-occupied pores and introduce discrepancies in evolutions of the maximum pore diameters during hydrate formation. Pore-filling hydrates reduce the maximum incircle and hydraulic diameters of fluid-occupied pores much more significantly than grain-coating hydrates; however, hydrate pore habits have minor effects on the maximum equivalent diameter reduction. Shapes of fluid-occupied pores change little due to the presence of grain-coating hydrates, but pore-filling hydrates lead to much fibrous shapes of fluid-occupied pores.

scholarly journals Modelling Methane Hydrate Saturation in Pores: Capillary Inhibition Effects

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5627
Author(s):  
Maria De La Fuente ◽  
Jean Vaunat ◽  
Héctor Marín-Moreno
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
Clapeyron Equation ◽  
Fine Grained ◽  
Chemical Potentials ◽  
Hydrate Saturation ◽  
Global Inventory

Experimental and field observations evidence the effects of capillarity in narrow pores on inhibiting the thermodynamic stability of gas hydrates and controlling their saturation. Thus, precise estimates of the gas hydrate global inventory require models that accurately describe gas hydrate stability in sediments. Here, an equilibrium model for hydrate formation in sediments that accounts for capillary inhibition effects is developed and validated against experimental data. Analogous to water freezing in pores, the model assumes that hydrate formation is controlled by the sediment pore size distribution and the balance of capillary forces at the hydrate–liquid interface. To build the formulation, we first derive the Clausius–Clapeyron equation for the thermodynamic equilibrium of methane and water chemical potentials. Then, this equation is combined with the van Genuchten’s capillary pressure to relate the thermodynamic properties of the system to the sediment pore size distribution and hydrate saturation. The model examines the influence of the sediment pore size distribution on hydrate saturation through the simulation of hydrate formation in sand, silt, and clays, under equilibrium conditions and without mass transfer limitations. The results show that at pressure–temperature conditions typically found in the seabed, capillary effects in very fine-grained clays can limit the maximum hydrate saturation below 20% of the host sediment porosity.

Estimation of the Formation Rate Constant of Methane Hydrate in Porous Media

SPE Journal ◽  
2013 ◽  
Vol 19 (02) ◽  
pp. 184-190 ◽  
Author(s):  
Ayako Fukumoto ◽  
Toru Sato ◽  
Fumio Kiyono ◽  
Shinichiro Hirabayashi
Keyword(s):  
Porous Media ◽  
Rate Constant ◽  
Methane Hydrate ◽  
Homogeneous Nucleation ◽  
History Matching ◽  
Formation Rate ◽  
Hydrate Formation ◽  
Computational Domain ◽  
Formation Experiment ◽  
Heat Transfers

Summary Hydrate formation and the relevant mass and heat transfers were numerically analyzed in a microscopic computational domain in which spherical glass beads, water, and methane gas were distributed separately. A hydrate-formation experiment was also carried out by use of a cylindrical pressure cell. The temperature in the cell was controlled by Peltier devices, which were attached to the outer walls of the cell to imitate the adiabatic boundary condition present in the numerical simulation. By history matching between the experiment and calculation, we first obtained a hydrate-formation rate constant per unit volume of water, assuming homogeneous nucleation. Then, after converting the rate by use of a surface-area model of water in porous media, we noted that the area-based rate constant and activation energy of the hydrate formation were estimated to be 6.33 × 1034 mol·m–2 Pa–1 s–1 and 238 × 103 J/mol, respectively, for temperatures of 1.5 to 3.4°C.

Memory effect of CO2-hydrate formation in porous media

Fuel ◽  
2021 ◽  
Vol 299 ◽  
pp. 120922
Author(s):  
Zhiang Wen ◽  
Yanbin Yao ◽  
Wanjing Luo ◽  
Xin Lei
Keyword(s):  
Porous Media ◽  
Memory Effect ◽  
Hydrate Formation

Investigating hydrate formation rate and the viscosity of hydrate slurries in water-dominant flow: Flowloop experiments and modelling

Fuel ◽  
2021 ◽  
Vol 292 ◽  
pp. 120193
Author(s):  
Shunsuke Sakurai ◽  
Ben Hoskin ◽  
Joel Choi ◽  
Tomoya Nonoue ◽  
Eric F. May ◽  
...  
Keyword(s):  
Formation Rate ◽  
Hydrate Formation

Imaging and Resistivity Studies of Saturation Gradients in Two-Phase Flow in 3-D Porous Media

1996 ◽  
Vol 464 ◽  
Author(s):  
E. H. Kawamoto ◽  
Po-Zen Wong
Keyword(s):  
Computed Tomography ◽  
Porous Media ◽  
Two Phase Flow ◽  
Water Saturation ◽  
Glass Beads ◽  
Water Phase ◽  
Phase Flow ◽  
Two Phase ◽  
Vertical Column ◽  
X Ray

ABSTRACTWe have carried out x-ray radiography and computed tomography (CT) to study two-phase flow in 3-D porous media. Air-brine displacement was imaged for drainage and imbibition experiments in a vertical column of glass beads. By correlating water saturation Sw with resistance R, we find that there is a threshold saturation S* ≈ 0.2, above which R(SW) ∼ Sw−2, in agreement with the empirical Archie relation. This holds true for both drainage and imbibition with littlehysteresis, provided that Sw remains above S*. Should Sw drop below S* during drainage, R(Sw) rises above the Archie prediction, exhibiting strong hysteresis upon reimbibition. This behavior suggests a transition in the connectivity of the water phase near S*, possibly due to percolation effects.

Kinetic analysis of dual impellers on methane hydrate formation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sotirios Nik Longinos ◽  
Mahmut Parlaktuna
Keyword(s):  
Power Consumption ◽  
Kinetic Analysis ◽  
Induction Time ◽  
Methane Hydrate ◽  
Formation Rate ◽  
Hydrate Formation ◽  
Mixed Flow ◽  
Pitched Blade Turbine ◽  
Decline Rate

Abstract This study investigates the effects of types of impellers and baffles on methane hydrate formation. Induction time, water conversion to hydrates (hydrate yield), hydrate formation rate and hydrate productivity are components that were estimated. The initial hydrate formation rate is generally higher with the use of Ruston turbine (RT) with higher values 28.93 × 10−8 mol/s in RT/RT with full baffle (FB) experiment, but the decline rate of hydrate formation was also high compared to up-pumping pitched blade turbine (PBTU). Power consumption is higher also in RT/RT and PBT/RT with higher value 392,000 W in PBT/RT with no baffle (NB) experiment compared to PBT/PBT and RT/PBT experiments respectively. Induction time values are higher in RT/RT experiments compared to PBT/PBT ones. Hydrate yield is always smaller when there is no baffle in all four groups of experiments while the higher values exist in experiments with full baffle. It should be noticed that PBT is the same with PBTU, since all experiments with mixed flow have upward trending.

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