Peculiarities of Methane Clathrate Hydrate Formation and Solid-State Deformation, Including Possible Superheating of Water Ice

Stern, Laura A.; Kirby, Stephen H.; Durham, W. B.

doi:10.1126/science.273.5283.1843

Cited by 297 publications

(335 citation statements)

References 23 publications

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“…Under these conditions, new XRPD peaks suddenly appeared (in o10 min), corresponding to the sI structure of the methane hydrate [27][28][29] . The formation process was completed in 30 min, and peak intensities did not change when continuing the process for another 30 min.…”

Section: Resultsmentioning

confidence: 99%

Methane hydrate formation in confined nanospace can surpass nature

et al. 2015

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Natural methane hydrates are believed to be the largest source of hydrocarbons on Earth. These structures are formed in specific locations such as deep-sea sediments and the permafrost based on demanding conditions of high pressure and low temperature. Here we report that, by taking advantage of the confinement effects on nanopore space, synthetic methane hydrates grow under mild conditions (3.5 MPa and 2°C), with faster kinetics (within minutes) than nature, fully reversibly and with a nominal stoichiometry that mimics nature. The formation of the hydrate structures in nanospace and their similarity to natural hydrates is confirmed using inelastic neutron scattering experiments and synchrotron X-ray powder diffraction. These findings may be a step towards the application of a smart synthesis of methane hydrates in energy-demanding applications (for example, transportation).

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Section: Resultsmentioning

confidence: 99%

Methane hydrate formation in confined nanospace can surpass nature

et al. 2015

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“…20 The ice was packed in layers using a solid cylindrical rod to pack the ice in place. Methane hydrate was formed by slowly pressurizing the vessel (to avoid the ice melting as a result of gas compression) to 6.2 MPa with 99.9% pure methane gas at 265 K. The vessel pressure decreased with time as the methane gas was consumed, owing to hydrate formation in the vessel.…”

Section: Methodsmentioning

confidence: 99%

Modeling Pure Methane Hydrate Dissociation Using a Numerical Simulator from a Novel Combination of X-ray Computed Tomography and Macroscopic Data

Gupta¹,

Moridis²,

Kneafsey³

et al. 2009

Energy Fuels

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The numerical simulator TOUGH+HYDRATE (T+H) was used to predict the transient pure methane hydrate (no sediment) dissociation data. X-ray computed tomography (CT) was used to visualize the methane hydrate formation and dissociation processes. A methane hydrate sample was formed from granular ice in a cylindrical vessel, and slow depressurization combined with thermal stimulation was applied to dissociate the hydrate sample. CT images showed that the water produced from the hydrate dissociation accumulated at the bottom of the vessel and increased the hydrate dissociation rate there.CT images were obtained during hydrate dissociation to confirm the radial dissociation of the hydrate sample. This radial dissociation process has implications for dissociation of hydrates in pipelines, suggesting lower dissociation times than for longitudinal dissociation. These observations were also confirmed by the numerical simulator predictions, which were in good agreement with the measured thermal data during hydrate dissociation. System pressure and sample temperature measured at the sample center followed the CH 4 hydrate L w +H+V equilibrium line during hydrate dissociation. The predicted cumulative methane gas production was within 5% of the measured data. Thus, this study validated our simulation approach and assumptions, which include stationary pure methane hydrateskeleton, equilibrium hydrate-dissociation and heat-and mass-transfer in predicting hydrate dissociation in the absence of sediments. It should be noted that the application of T+H for the pure methane hydrate system (no sediment) is outside the general applicability limits of T+H. This approach is generally not recommended into the regime explored here (no sediment), but it can be considered only after fully evaluating the conditions and being fully aware of the physics and limitations.

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“…In these models, hydrate is assumed to dissociate instantaneously once the equilibrium condition is reached. Experimental work by Makogon (2001) and Stern (1996) suggests otherwise. Kinetic models of pure hydrate dissociation have been proposed by Kim et al (1987) and Bishnoi (2000, 2001).…”

Section: -D Models For Formation Of Methane Hydrate In Marine Sedimementioning

confidence: 99%

Petrophysical Characterization and Reservoir Simulator for Methane Gas Production from Gulf of Mexico Hydrates

Mohanty¹,

Cook²,

Hakimuddin³

et al. 2006

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Gas hydrates are crystalline, ice-like compounds of gas and water molecules that are formed under certain thermodynamic conditions. Hydrate deposits occur naturally within ocean sediments just below the sea floor at temperatures and pressures existing below about 500 meters water depth. Gas hydrate is also stable in conjunction with the permafrost in the Arctic. Most marine gas hydrate is formed of microbially generated gas. It binds huge amounts of methane into the sediments. Estimates of the amounts of methane sequestered in gas hydrates worldwide are speculative and range from about 100,000 to 270,000,000 trillion cubic feet (modified from Kvenvolden, 1993). Gas hydrate is one of the fossil fuel resources that is yet untapped, but may play a major role in meeting the energy challenge of this century.In this project novel techniques were developed to form and dissociate methane hydrates in porous media, to measure acoustic properties and CT properties during hydrate dissociation in the presence of a porous medium. Hydrate depressurization experiments in cores were simulated with the use of TOUGHFx/HYDRATE simulator. Input/output software was developed to simulate variable pressure boundary condition and improve the ease of use of the simulator. A series of simulations needed to be run to mimic the variable pressure condition at the production well.The experiments can be matched qualitatively by the hydrate simulator. The temperature of the core falls during hydrate dissociation; the temperature drop is higher if the fluid withdrawal rate is higher. The pressure and temperature gradients are small within the core. The sodium iodide concentration affects the dissociation pressure and rate. This procedure and data will be useful in designing future hydrate studies. INTERTEK WESTPORT TECHNOLOGY CENTER

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Peculiarities of Methane Clathrate Hydrate Formation and Solid-State Deformation, Including Possible Superheating of Water Ice

Cited by 297 publications

References 23 publications

Methane hydrate formation in confined nanospace can surpass nature

Methane hydrate formation in confined nanospace can surpass nature

Modeling Pure Methane Hydrate Dissociation Using a Numerical Simulator from a Novel Combination of X-ray Computed Tomography and Macroscopic Data

Petrophysical Characterization and Reservoir Simulator for Methane Gas Production from Gulf of Mexico Hydrates

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