The implications of the presence of gas hydrates in a producing gas reservoir are discussed. It is concluded that such a reservoir should contain primarily methane in the free gas state, but could contain considerable amounts of propane or ethane in the hydrate phases which should consist of a ...

World resources of natural gas in hydrate form are on the order of trillions of cubic meters. Thermophysical property measurements are vital to the determination of the exploitability of this resource. The natural gas hydrates are clathrates; the hydrate ...

I methane hydrate and sII methane+ethane hydrate. Gas occlusion resulting from rapid gas growth of methane hydrate was measured immediately after formation. The Raman shift for methane free gas was coincident with that of methane in the small 512 ...

Knowledge of cage occupancies and hydration numbers (n) of naturally occurring gas hydrate in a local environment is important for the improvement in global estimates of hydrate-bound natural gas. We report on local differences in cage occupancies and hydration number of ...

... Sponsors: ONRG International Methane Hydrate Research and Development, ONR, Department of Energy NETL Page 4. 2 ii. DISCLAIMER ...

Natural gas hydrates are a potential source of energy and may play a role in climate change and geological hazards. Most natural gas hydrate appears to be in the form of 'structure I', with methane as the trapped guest molecule, although 'structure II' hydrate has also been ...

hydrate [5,6]. Due to the importance of this study we have inclu- ded methane hydrate and the structure of natu- ral gas hydrates (e.g. methane hydrate) have been discovered on the ocean sea floors confirm the guest-host coupling for structure II ...

-member of a spectrum of similar systems. Our recent observa- tions of pockets of free gas suggest that shallow hydrate venting of methane gas were observed as were small pockets of free gas and hydrate crusts in the sediment and transient gas discharge. Four generalized ...

-component hydrate systems: ethane (C2H6), cyclopropane (C3H6), methane (CH4), argon (Ar), and chlorodifluoromethane and structure II clathrates formed by the simple hydrates of methane and argon, respectively. Thus for the cages of the theoretical (unstable) structure II methane hydrate. ...

We measured the isotopic compositions of methane (C1) and ethane (C2) of hydrate-bound gas and of dissolved gas in pore water retrieved from bottom sediments in Lake Baikal. Both structure I (sI:3%C2) and II (sII:14%C2) gas hydrates are observed in the ...

The formation of hydrate plugs in oil and gas pipelines is a serious industrial problem and recently there has been an increased interest in the use of alternative hydrate inhibitors as substitutes for thermodynamic inhibitors like methanol. We show here that antifreeze proteins (AFPs) possess the ability to modify structure ...

The formation of hydrate plugs in oil and gas pipelines is a serious industrial problem and recently there has been an increased interest in the use of alternative hydrate inhibitors as substitutes for thermodynamic inhibitors like methanol. We show here that antifreeze proteins (AFPs) possess the ability to modify structure ...

There has been little effort to use gas hydrates to separate hydrocarbons, except in instances where mixtures could be separated on the basis of the failure of one or more of the components to form simple hydrates. In the present investigation, CD3U-CD6U hydrocarbons are separated on the basis of their respective abilities to form ...

This book presents papers on gas hydrates. Topics considered include gas hydrates as clathrate ices, gas hydrate phase equilibrium, the thermodynamics and chemical reaction kinetics of gas hydrate formation, elastic wave velocities ...

For the nondestructive inspection of gas hydrates, terahertz (THz) time-domain spectroscopy (TDS) was applied to tetrahydrofuran (THF) hydrate and propane hydrate. The absorption of propane hydrate monotonically increases with frequency, similar to the case of ice, while THF ...

Gas hydrates are becoming an attractive way of storing and transporting large quantities of natural gas, although there has been little effort to understand the preferential occupation of heavy hydrocarbon molecules in hydrate cages. In this work, we present the formation kinetics of mixed ...

Gas hydrates are becoming an attractive way of storing and transporting large quantities of natural gas, although there has been little effort to understand the preferential occupation of heavy hydrocarbon molecules in hydrate cages. In this work, we present the formation kinetics of mixed ...

We report the in situ observation from diffraction data of the conversion of a gas hydrate with the structure II (sII) lattice to one with the structure I (sI) lattice. Initially, the in situ formation, dissociation, and reactivity of argon gas clathrate hydrate was ...

First time in situ Raman measurements were performed on natural ocean hydrates at 850m depth in the Barkley Canyon, off Vancouver Island, Canada. Employing the sea-going spectrometer, DORISS II, the ROV Tiburon positioned the Raman probe allowing for direct interrogation of undisturbed massive exposed hydrate. The ...

Intimate associations of two gas hydrate structures seem to be uncommon in most known hydrate deposits. Here we report on a mixture of hydrate structure I (sI) and structure II (sII) from the Chapopote asphalt volcano in the southern Gulf of Mexico. Gas ...

formation under flow conditions. II. Evidence of the contact-induced agglomeration mechanism Methane hydrate) Rheology of methane hydrate slurries during their crystallisation in a water in dodecane emulsion under et 4, Avenue de Bois Pr�au ; 92852 Rueil Malmaison, France Abstract: Line blockage due to gas ...

Continuous leakage of methane to the oceans from hydrate reservoirs that partially are exposed towards the seafloor is an increasing international concern, as the greenhouse gas methane is significantly more (c. 20 times) aggressive than CO2. In Norway we have research groups with interest and experience on natural seeps and gas ...

In the past few years, extensive analyses have been carried out for characterizing the natural gas hydrate samples from Cascadia, offshore Vancouver Island; Mallik, Mackenzie Delta; Mount Elbert, Alaska North Slope; Nankai Trough, offshore Japan; Japan Sea and offshore India. With the results obtained, it is possible to give a general picture of the ...

Gas hydrates are nonstoichiometric clathrate compounds, in which a gas molecule (guest) is trapped in a cage formed by surrounding hydrogen bonded water molecules (hosts). Natural gas hydrates are present in two types of structures, I and II, with each structure having two ...

In underwater hydrocarbon seepage environments, gas hydrates are considered to play a significant role as shallow gas reservoirs and buffers for light hydrocarbon expulsion. Here we report on mixed hydrate structures from the Chapopote Knoll in the southern Gulf of Mexico and discuss several options on how a ...

World resources of natural gas in hydrate form are on the order of trillions of cubic meters. Thermophysical property measurements are vital to the determination of the exploitability of this resource. The natural gas hydrates are clathrates; the hydrate lattice exists in one of two special ...

... properties for gas hydrates generally were measured on analog systems such as ice and non-methane hydrates or ... ...

The Gulf of Mexico gas hydrates Joint Industry Project (the JIP), a cooperative research program between the US Department of Energy and an international industrial consortium under the leadership of Chevron, conducted its �Leg II� logging-while-drilling operations in April and May of 2009. GC 955 was one of three sites drilled ...

Indian National Gas Hydrate Program Expedition 01 has established that clay-rich marine sediment from the Krishna-Godavari (KG) basin in the eastern Indian margin hosts one of the richest gas hydrate deposits in the world. Resistivity at-bit images and pressure cores reveal that the gas ...

The Gulf of Mexico gas hydrates Joint Industry Project (the JIP), a cooperative research program between the US Department of Energy and an international industrial consortium under the leadership of Chevron, conducted its �Leg II� logging-while-drilling operations in April and May of 2009. JIP Leg II was ...

During the last past decade, IFREMER has participated to numerous surface/diving oceanographic cruises to investigate fluid circulation, cold seep discharges and gas hydrate formation on continental margins. The development of sampling tools, instrumentations and laboratory apparatuses related to gas hydrate study ...

Gas Hydrates Research Group ______________________________________________________________ GAS HYDRATES RESEARCH AT THE UNIVERSITY OF CALGARY by P. R. Bishnoi (Raj) #12;Gas Hydrates Research Group � Decomposition #12;Gas Hydrates ...

In the offshore part of Beaufort-Mackenzie Basin depth of methane hydrate stability reaches more than 1.5 km. However, there are areas in the western part of the basin where there are no conditions of methane hydrate stability. Construction of the first contour maps displaying thickness of hydrate stability zones as well as ...

A seafloor survey of Barkley Canyon, located off the coast of Vancouver Island, was conducted in August 2002. This survey revealed massive outcrops of gas hydrates exposed as large slabs (6-8m in length) and thinly sedimented mounds (2-3m high). Molecular and isotopic analyses of gas hydrates collected at this ...

Among a variety of cyclic ether, cyclic ester, and cyclic ketone compounds, six new formers were found to form binary sII or sH hydrates with CH(4) gas. Hydrate-phase equilibria for all the hydrate formers were measured. The results obtained showed distinct relationships between the ...

Dissociation behavior of methane-ethane mixed gas hydrate coexisting structures I and II at constant temperatures less than 223 K was studied with use of powder X-ray diffraction and solid-state (13)C NMR techniques. The diffraction patterns at temperatures less than 203 K showed both structures I and II ...

The Gulf of Mexico Gas Hydrate Joint Industry Project Leg II drilling program visited three sites in the Gulf of Mexico during a 21 day drilling program in April and May, 2009. Using both petroleum systems and seismic stratigraphic approaches, the exploration focus for Leg II was to identify sites with the ...

At present the serious attention is given to the analysis of cyclic climatic changes and metastable methane hydrates existence at natural conditions during its decomposition. Atmospheric methane as well as carbon dioxide is greenhouse gas approximately with 20 times more activity at the same concentration. There are some hypotheses dealing with an ...

This work presents a thermodynamic model of equilibrium states of binary structure II gas hydrates of hydrogen with different promoters based on the van der Waals-Platteeuw statistical thermodynamic model. Since the determination of the occupancy of the small cavities by hydrogen is still an unresolved question, the model allows for ...

In situ formations of CH(4)-C(2)H(6) mixed gas hydrates were made using high flux neutron diffraction at 270 K and 5 MPa. For this purpose, a feed gas composition of CH(4) and C(2)H(6) (95 mol% CH(4)) was employed. The rates of transformation of spherical grains of deuterated ice Ih into hydrates were measured by ...

... km/s range, although sediment-gas hydrate is more ... The presence of hydrates and the velocity ... 1 kHz; unhydrated sediment, hydrated sediment, and ...

A new high-pressure-low-temperature cell was developed for in situ observations of gas hydrates by powder x-ray diffraction. The experimental setup allows investigating hydrate formation and dissociation as well as transformation processes between different hydrate crystal structures as a function of pressure, ...

A new high-pressure-low-temperature cell was developed for in situ observations of gas hydrates by powder x-ray diffraction. The experimental setup allows investigating hydrate formation and dissociation as well as transformation processes between different hydrate crystal structures as a function of pressure, ...

An overview of recent structural work focusing on the gas hydrates of methane and carbon dioxide is given. Both the crystal structure and the microstructure are considered. We report on the pressure-dependent molecular structure of methane clathrate hydrate using laboratory-made hydrogenous and deuterated samples investigated by ...

... Although massive gas hydrates on the seafloor are one of the most visible types of gas hydrate accumulation, they appear to be very localized. ...

During the Ulleung Basin Gas Hydrate Expedition 1, gas-hydrate-bearing sediments down to about depths of bottom simulating reflectors were successfully recovered from three deep-water sites offshore Korea. Especially, drilling in the site UBGH1-9 revealed various gas hydrate saturation with ...

Microscopy, confocal Raman spectroscopy and powder X-ray diffraction were used for in situ investigations of the CO2-hydrocarbon exchange process in gas hydrates and its driving forces. The study comprises the exposure of simple structure I CH4 hydrate and mixed structure II CH4-C2H6 and CH4-C3H8 ...

Small grain-like gas hydrates were observed commonly in muddy soft sediments in the mud volcano system in the Kumano forearc basin, Nankai Trough, Japan, during the CK09-01 Leg 1 Chikyu training cruise. Although deep gas hydrate deposits disseminated in the large pore of sandy sediments are distributed ubiquitously ...

The Gulf of Mexico Gas Hydrate Joint Industry Project Leg II drilling program visited three sites in the Gulf of Mexico during a 21 day drilling program in April and May, 2009. Using both petroleum systems and seismic stratigraphic approaches, the exploration focus for Leg II was to identify sites with the ...

The interconversion of methane-ethane hydrate from metastable to stable structures was studied using Raman spectroscopy. sI and sII hydrates were synthesized from methane-ethane gas mixtures of 65% or 93% methane in ethane and water, both with and without the kinetic hydrate inhibitor, ...

Gas hydrates represent an attractive way of storing large quantities of gas such as methane and carbon dioxide, although to date there has been little effort to optimize the storage capacity and to understand the trade-offs between storage conditions and storage capacity. In this work, we present estimates for gas ...

This study presents the influences of additional guest molecules such as C2H6, C3H8, and CO2 on methane hydrates regarding their thermal behavior. For this purpose, the onset temperatures of decomposition as well as the enthalpies of dissociation were determined for synthesized multicomponent gas hydrates in the range of 173-290 K at ...

... Methane hydrate is a naturally occurring crystalline ... Descriptors : *HYDRATES, *GASES, *OCEANS, *METHANE, CRYSTAL STRUCTURE ...

... Workshop of the International Committee on Gas Hydrates Research and ... and to promote international collaboration on methane hydrate research. ...

... with seismic summaries of potential deep sediment hydrates deposits. ... and microbiological technologies for prospecting hydrate distribution and ...

This invention relates to a method of storing gas using gas hydrates comprising forming gas hydrates in the presence of a water-surfactant solution that comprises water and surfactant. The addition of minor amounts of surfactant increases the gas ...

Ambient temperature is a critical factor determining the stability of gas hydrate deposits on continental margins. To study this process directly under varying conditions, a monitoring array comprising a time-lapse camera and in-situ temperature probes was deployed at a hydrocarbon seep known as Bush Hill, where gas ...

In the Department of Energy (DOE), Morgantown Energy Technology Center's (METC's) Gas Hydrates Laboratory, a proven method of synthesizing methane hydrate has been developed. The synthesis technique involves conversion of frost to gas hydrate in a high-pr...

... that is twice that of all other fossil fuels on earth � combined. But extracting gas from gas hydrates is challenging because hydrates are unstable at surface temperatures and pressures. Gas hydrates, coal...

The effects of LMGS (large molecule guest substance) amount on the thermodynamics of natural gas hydrates, as well as structural characteristics of mixed hydrates of LMGS and natural gas, have been studied. The addition of 1.7 wt % neohexane (NH) to water induced inhibition of natural gas ...

The conversion of CH4 hydrate to CO2 hydrate offers, in principle, a way of sequestering CO2, with the additional recovery of CH4 gas as an energy source. We report results from the first in-situ oceanic experiment on this reaction, carried out in August 2006 at the massive thermogenic hydrate mounds in 850 m water ...

... is technically feasible to produce gas from gas hydrates. Gas hydrates are a naturally occurring "ice-like" combination of ... first modern, fully integrated production testing of gas hydrates are being d...

A collection of Russian theories, experiments and field studies on natural gas hydrates is presented. The potential for discovering deposits of solid natural gas in permafrost zones and in some offshore areas is emphasized. The contents include: a study of hydrate properties and occurrences; problems of ...

A new predictive computational method for classifying clathrate hydrate promoter molecules is presented, based on the interaction energies between potential promoters and the water networks of sII and sH clathrates. The motivation for this work is identifying promoters for storing hydrogen compactly in clathrate hydrates. As a first ...

The first hydration shell of the deprotonated glycine is built up by the discrete hydration model. The potential energy surfaces (PESs) of the deprotonated glycine and its hydration complexes with different number of water molecules have been scanned by the Monte Carlo multiple minimum (MCMM) conformational search analysis with the ...

... and lateral distribution of gas hydrates has with ... is stable only within the methane hydrate stability zone ... The zone of hydrated sediments may be thin ...

... Coordinated, High-Resolution Studies of Hydrated Sediments JF ... of the 4th International Conference on Gas Hydrates, of hydrate formed (large vs. ...

... Coordinated, High-Resolution Studies of Hydrated Sediments. ... ideal for studies of marine gas hydrates. ... study the impact of hydrate dissociation on ...

The kinetics of CH(4)-C(2)H(6) replacement in gas hydrates has been studied by in situ neutron diffraction and Raman spectroscopy. Deuterated ethane structure type I (C(2)H(6) sI) hydrates were transformed in a closed volume into methane-ethane mixed structure type II (CH(4)-C(2)H(6) sII) ...

In the spring of 2009, the Gulf of Mexico Gas Hydrate Joint Industry Project (JIP) Leg II drilled several holes in the Gulf of Mexico in the search for gas hydrate-filled reservoirs. In Walker Ridge Block 313, Hole H was drilled in a location where the gas ...

We have show that a sII clathrate hydrate containing 1,4-thioxane (TO) will form under the appropriate pressure and temperature conditions. The molecular size of TO poised it at the boundary between sII hydrate formation either as the sole cage occupant, or where a second help gas molecule is ...

For almost 30 years. serious interest has been directed toward natural gas hydrate, a crystalline solid composed of water and methane, as a potential (i) energy resource, (ii) factor in global climate change, and (iii) submarine geohazard. Although each of these issues can affect human welfare, only (iii) is considered to be of ...

For almost 30 years. serious interest has been directed toward natural gas hydrate, a crystalline solid composed of water and methane, as a potential (i) energy resource, (ii) factor in global climate change, and (iii) submarine geohazard. Although each of these issues can affect human welfare, only (iii) is considered to be of ...

For almost 30 years. serious interest has been directed toward natural gas hydrate, a crystalline solid composed of water and methane, as a potential (i) energy resource, (ii) factor in global climate change, and (iii) submarine geohazard. Although each of these issues can affect human welfare, only (iii) is considered to be of ...

In hydrate-based desalination or other water purification conducted using naturally buoyant or trapped-gas-assisted buoyancy hydrate in a hydrate fractionation column, a portion of fresh or purified product water is extracted from an upper, hydrate dissoc...

Gas hydrates are solid crystalline compounds of water and methane that are similar to snow. They form in and block gas wells and lines and cause fouling of heat exchangers when the gas is cooled. Here, finally, is long-awaited information detailing the successful methods for not only removing ...

Sulfur hexafluoride (SF6), whether pure or mixed with inexpensive inert gas, has been widely used in a variety of industrial processes, but it is one of the most potent greenhouse gases. For this reason, it is necessary to separate and/or collect it from waste gas streams. In this study, we investigated the pure SF6 and SF6-N2 mixture ...

Methodology and procedures for the study of hydrate cores are detailed. Topics discussed are the (1) equipment and procedures for the formation and evaluation of hydrate cores in the laboratory, (2) the thermodynamic properties of gas hydrates, (3) the enthalpy of hydrate dissociation, (4) ...

Research was conducted on hydrate gas, particularly on the conditions of its formation in permafrost strata and in pipelines operated under Arctic conditions. This book contains six chapters entitled: study of hydrate properties and occurrences; problems of hydrate kinetics; preventing the formation of ...

Elastic velocities and hydraulic permeability of gas hydrate-bearing sediments strongly depend on how gas hydrate accumulates in pore spaces and various gas hydrate accumulation models are proposed to predict ...

Contents: Special Issue: Research on Gas Hydrate-Preface; Introduction to Exploration Research on Gas Hydrates; Equilibrium Conditions of Gas Hydrate From Mixtures of Methane and Ethane and Outline of Experimental Apparatus for Gas ...

Clathrate hydrates formed from binary gas mixtures of methane and other small lipophilic molecules change from the sI phase to sII and back depending on the concentration of methane in the mixtures. In contrast, pure methane hydrate under increasing pressure transforms first from sI to sII and ...

Gas Hydrate is found in sub-oceanic sediments in the polar regions (shallow water) and in continental slope sediments ( ... ...

In recent years it has become generally accepted that gas hydrates represent a potential important future energy resource, a significant drilling and production hazard, a potential contributor to global climate change, and a controlling factor in seafloor stability and landslides. Research drilling and coring programs carried out by the Ocean Drilling ...

Samples of thermogenic hydrocarbon gases, from vents and gas hydrate mounds within a sea-floor chemosynthetic community on the Gulf of Mexico continental slope at about 540 m depth, were collected by research submersible. The study area is characterized by low water temperature (mean = 7 C), high pressure (about 5,400 kPa), and abundant structure ...

... for gas hydrates is M.6H2O, for structural reasons larger molecules have higher water contents, or more correctly, their content in the hydrate former ...

Hydrates contains highly concentrated methane, which is could be important both as an energy resource and as a factor in global climate change. Because gas hydrates change the...

Gas Hydrate Research Home Facilities & Tools Ocean Sequestration Astrobiology Desalination Nucleation/Dissociation Hydrates Workshop Pictures Gallery Videos Researchers Contacts...

... the region just below the gas-hydrate stability zone. ... FAULTS(GEOLOGY), *METHANE, *SEDIMENTS, SYMPOSIA, HYDRATES, MARINE GEOLOGY ...

Bottom-simulating reflections (BSRs) are probably the most commonly used indicators for gas hydrates in marine sediments. It is now widely accepted that BSRs are primarily caused by free gas beneath gas-hydrate-bearing sediments. However, our insight into BSR formation to date is mostly limited to theoretical ...

How gas hydrates form in Nature marine George E. Claypool Rice U. Hydrate Workshop Nov. 12, 2003 #12;HYDRATE FORMATION CONDITIONS � gas hydrate forms in methane-saturated formation waters under conditions of marine gas hydrate ...

Methane hydrate gas could be a tremendous energy resource if methods can be devised to produce this gas economically. This paper examines two methods of producing gas from hydrate deposits by the injection of hot water or steam, and also examines the feasibility of hydraulic fracturing and ...

This paper presents the phase behavior of multicomponent gas hydrate systems formed from primarily methane with small amounts of ethane and propane. Experimental conditions were typically in a pressure range between 1 and 6 MPa, and the temperature range was between 260 and 290 K. These multicomponent systems have been investigated using a variety of ...

We describe a method for calculating free energies and chemical potentials for molecular models of gas hydrate systems using Monte Carlo simulations. The method has two components: (i) thermodynamic integration to obtain the water and guest molecule chemical potentials as functions of the hydrate occupancy; (ii) ...

In 2009, the U.S. Department of Energy, National Energy Technology Laboratory expedition in collaboration with the U.S. Geological Survey confirmed that gas hydrate occurs at high saturations within reservoir-quality sands in the Gulf of Mexico. A dataset of density and resistivity logs from the gas hydrate ...

This study aims to examine the thermodynamic feasibility of separating sulfur hexafluoride (SF(6)), which is widely used in various industrial fields and is one of the most potent greenhouse gases, from gas mixtures using gas hydrate formation. The key process variables of hydrate phase equilibria, ...

Gas Hydrates: An Extraordinary Compound Gas hydrates are crystalline solids that consist of a gas that of the entire world's coal, oil, and conventional natural gas combined. In the Gulf of Mexico alone, a 3000-km2 area contains methane equal to thirty times the U. S. ...

Gas hydrates are often suggested as a future energy resource. This doctoral thesis improves the understanding of the concentration and distribution of natural submarine gas hydrates. The presence of these hydrates are commonly inferred from strong bottom ...

Natural gas hydrates have been detected in many regions of the world and vast quantities of natural gas are expected to exist in the hydrate state in suboceanic sediments as well as in the formations below the permafrost base. Since gas hydrates are a con...

Silica clathrate compounds (clathrasils) and clathrate hydrates are structurally analogous because both materials have framework structures with cage-like voids occupied by guest species. The following three structural types of clathrate hydrates are recognized in nature: cubic structure I (sI); cubic structure II ...

Over the past decade, the interest in using CH4-hydrates as an energy resource and CO2-hydrates as a storage option for anthropogenic CO2 has grown in the scientific community as well as in the oil and gas industry. Among all the techniques used to characterize gas hydrates, the ...

Volume II of a two volume publication is presented in which aspects of conditioning and/or processing of natural gas for sale are examined. Chapters are included on absorption and fractionation, compression and expansion of fluids, refrigeration systems, liquefaction processes, water-hydrocarbon system behavior, dehydration and sweetening, adsorption ...

An examination is made of the potential for recovering gas from naturally occurring hydrates. Factors to be considered in such a study are (1) location of the hydrate fields, (2) purity of hydrates in the reservoir, (3) types of media in which hydrates form, (4) thermodynamic conditions of ...

We compare dissolution rates of pure, porous, compacted, and oil-contaminated sI methane hydrate and sII methane-ethane hydrate to rates measured previously on pure, compacted, sI methane hydrate and sI carbon dioxide hydrate (Rehder et al., Fall AGU 2001). Laboratory-synthesized test specimens ...

Experimental data on the pressure dependence of unit cell parameters for the gas hydrates of ethane (cubic structure I, pressure range 0-2 GPa), xenon (cubic structure I, pressure range 0-1.5 GPa) and the double hydrate of tetrahydrofuran+xenon (cubic structure II, pressure range 0-3 GPa) are presented. ...

Gas hydrates are crystalline substances composed of water and gas, in which a solid-water-lattice accommodates gas molecules in a cage-like structure. Gas hydrates are globally widespread in permafrost regions and beneath the sea in sediment of outer cont...

Gas hydrates research, one of the new efforts in DOE's program on unconventional gas recovery, is focused on the basic sciences related to the formation and dissociation of naturally formed gas hydrate deposits. The research goal is to determine the exten...

Significant events have transpired on the natural gas hydrate research and development front since "Future Supply Potential of Natural Gas Hydrates" appeared in Natural Gas 1998 Issues and Trends and in the Potential Gas Committee's 1998 biennial report.

Methane hydrate gas could be a tremendous energy resource if methods can be devised to produce this gas economically. This paper examines two methods of producing gas from hydrate deposits by the injection of hot water or steam, and also examines the feas...

Gas hydrates (clathrates) are plentiful on Earth, forming ice-like gas ... Terrestrial gas hydrates may contain more hydrocarbons (natural gas) than all ...

Hydrate Ridge off the coast of Oregon, USA, is a prime example for gas hydrate occurrences in active margin settings. It is part of the Cascadia Margin and was the focus of Ocean Drilling Program (ODP) Leg 204, which successfully recovered fluids from nine sites from the southern part of the ridge. Iodide concentrations in pore fluids ...

Knowledge of thermal expansivity can aid in the understanding of both microscopic and macroscopic behavior of clathrate hydrates. Diffraction studies have shown that hydrate volume changes significantly (as much as 1.5% over 50 K) as a function of temperature. It has been demonstrated previously via statistical mechanics that a minor change in ...

In order to accurately estimate the thermodynamic properties of hydrogen clathrate hydrates, we developed a method based on the solid solution theory of van der Waals and Platteeuw. This model allows one to take into account the influence of guest molecules on the host lattice and guest-guest interactions--especially when more than one guest molecule occupies a cage. The free ...

Methane hydrates, ice-like compounds in which methane is held in crystalline cages formed by water molecules, are widespread in areas of permafrost such as the Arctic and in sediments on the continental margins. They are a potentially vast fossil fuel energy source but, at the same time, could be destabilized by changing pressure-temperature conditions due to climate change, ...

Despite the industrial implications and worldwide abundance of gas hydrates, the formation mechanism of these compounds remains poorly understood. We report direct molecular dynamics simulations of the spontaneous nucleation and growth of methane hydrate. The multiple-microsecond trajectories offer detailed insight into the process of ...

Recombinant antifreeze proteins (AFPs), representing a range of activities with respect to ice growth inhibition, were investigated for their abilities to control the crystal formation and growth of hydrocarbon hydrates. Three different AFPs were compared with two synthetic commercial inhibitors, poly-N-vinylpyrrolidone (PVP) and HIW85281, by using multiple approaches, which ...

Gas hydrates look like ordinary ice. However, if a piece of such ice is put into warm water its behavior will be different from the ordinary melting of normal ice. In contrast, gas hydrates cause bubbles in the warm water, which indicates the high content of gas in the ...

in a large gas-hydrate reservoir" by Dickens et al. (Nature, 1997). "Methane hydrate and free gasEstimates of worldwide hydrate resources are large, but they are also uncertain because of inherent difficulties in determining the amount of gas hydrate present in ocean sed- ...

In this study, the phase behavior and quantitative determination of hydrate composition and cage occupancy for the mixed CH(4) + C(2)H(6) + C(3)H(8) hydrates were closely investigated through the experimental measurement of three-phase hydrate (H)-water-rich liquid (L(W))-vapor (V) equilibria and (13)C NMR spectra. To examine the ...