Methane hydrates (MHs) are present in large amounts in the ocean floor and permafrost regions. Methane and hydrogen hydrates are being studied as future energy resources and energy storage media. To develop a method for gas production from natural MH-bearing sediments and hydrate-based technologies, it is imperative to understand the thermal properties of gas hydrates. The thermal properties' m...

The amounts of hydrocarbon gases trapped in natural hydrate accumulations are enormous, leading to a recent interest in the evaluation of their potential as an energy source. Earlier studies have demonstrated that large volumes of gas can be readily produced at high rates for long times from gas hydrate accumulations by means of depressurization-induced dissociation, using conventional technolo...

The main purpose of this study is to investigate the production behaviors of gas hydrate at site DK-2 in the Qilian Mountain permafrost using the novel five-spot well (5S) system by means of numerical simulation. The whole system is composed of several identical units, and each single unit consists of one injection well and four production wells. All the wells are placed horizontally in the hyd...

Experimental data on the kinetics of propane hydrate dissociation at 0.1 MPa and different external temperatures were obtained. A two-stage mechanism of hydrate dissociation was observed visually. In the first stage hydrate dissociated into metastable water and gas. During the second stage the metastable water crystallized into ice. The release of metastable water during hydrate dissociation an...

Gas hydrates, low molecular weight gas molecules trapped in water-ice “cages,” have gained international attention over the last few years for energy, safety, and environmental reasons. In 2000 CODATA (Committee on Data for Science and Technology, International Council for Science) established a task group for Data on Natural Gas Hydrates, which aims to develop a comprehensive information syste...

One of the options suggested for methane recovery from natural gas hydrates is molecular replacement of methane by suitable guests like CO2 and N2. This approach has been found to be feasible through many experimental and molecular dynamics simulation studies. However, the long term stability of the resultant hydrate needs to be evaluated; the decomposition rate of these hydrates is expected to...

Because of availability, as well as economical and environmental considerations, natural gas is projected to be the premium fuel of the 21st century. Natural gas production involves risk of the shut down of onshore and offshore operations because of blockage from hydrates formed from coproduced water and hydrate-forming species in natural gas. Industry practice has been usage of thermodynamic i...

We study diffusive transport of aqueous methane in sea sediments, which is important for formation of methane hydrate and gas deposits and has even been claimed to be principal methane transport mechanism for some geological systems. The isothermal diffusion law (Fick's law), D X = − ∇ J , which is employed in the literature for investigations on methane hydrate, is shown to significantly devia...

Despite observations of massive methane release and geohazards associated with gas hydrate instability in nature, as well as ductile flow accompanying hydrate dissociation in artificial polycrystalline methane hydrates in the laboratory, the destabilising mechanisms of gas hydrates under deformation and their grain-boundary structures have not yet been elucidated at the molecular level. Here we...

Natural gas hydrates are icy crystalline materials that contain hydrocarbons, which are the primary energy source for this civilization. The abundance of naturally occurring gas hydrates leads to a growing interest in exploitation. Despite their potential as energy resources and in industrial applications, there is insufficient understanding of hydrate kinetics, which hinders the utilization of...