Simulation of Gas Production From a Reservoir Containing Both Gas Hydrates and 
Free Natural Gas

Holder, Gerald M.; Angert, P.F.

doi:10.2523/11105-ms

Cited by 45 publications

(51 citation statements)

References 2 publications

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“…Figure 6 shows the evolution over time of the pressure at the wellbore gridblock immediately below the initial interface (at r = 0.05 m and z =-15.05 m). The pressure in Case 1 is lower than the Holder et al 3 results, but the difference is rather small. It appears that the reason for the similarity of the answers is that the finer discretization and higher dissociation in our model produce roughly the same results as the coarser discretization and lower dissociation of the Holder et al 3 model.…”

Section: Test Problemcontrasting

confidence: 58%

“…The pressure in Case 1 is lower than the Holder et al 3 results, but the difference is rather small. It appears that the reason for the similarity of the answers is that the finer discretization and higher dissociation in our model produce roughly the same results as the coarser discretization and lower dissociation of the Holder et al 3 model. The pressures in Case 2 are larger than those in Case 1 due to the higher permeability (and, consequently, the higher hydrate dissociation) of the gas phase.…”

Section: Test Problemcontrasting

confidence: 58%

“…Figure 4 shows the cumulative contribution of hydrate dissociation to the total gas production as a function of production times. Compared to the Holder et al 3 results, our simulation indicates a much higher contribution of dissociated gas in Case 1 (which corresponds to the Holder et al 3 conditions). The difference is attributed to the fact that in our model a gas phase emerges in the hydrate zone, which keeps expanding as the dissociation continues and the released water drains.…”

Section: Test Problemcontrasting

confidence: 55%

“…The problem was first studied by Holder et al 3 , who solved the uncoupled pressure and temperature equations by using a 2-D grid for pressure calculations and a 3-D grid for temperature calculations. In their approach, the heat transferred to the interface (due to the temperature gradient) was used for the hydrate dissociation, and there was no energy balance based on the existing phases and their enthalpies.…”

Section: Test Problemmentioning

confidence: 99%

“…The reservoir radius was r = 567.5 m, and its thickness was 30.5 m (100 ft) equally distributed between the hydrate layer and the free gas zone. These dimensions result in a reservoir with a volume identical to the cartesian system of Holder et al 3 .…”

Section: Test Problemmentioning

confidence: 99%

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Numerical Studies of Gas Production from Methane Hydrates

Moridis

2002

SPE Gas Technology Symposium

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractEOSHYDR2 is a new module for the TOUGH2 general-purpose simulator for multi-component, multiphase fluid and heat flow in the subsurface. By solving the coupled equations of mass and heat balance, EOSHYDR2 can model the non-isothermal gas release, phase behavior and flow of fluids and heat under conditions typical of common natural hydrate deposits (i.e., in the permafrost and in deep ocean sediments) in complex formations, and can describe binary hydrocarbon systems involving methane.EOSHYDR2 includes both an equilibrium and a kinetic model of hydrate formation and dissociation. The model accounts for up to four phases (gas phase, liquid phase, ice phase and hydrate phase) and up to nine components (hydrate, water, native CH 4 and CH 4 from hydrate dissociation, a second native and dissociated hydrocarbon, salt, water-soluble inhibitors and a heat pseudo-component). The mass components are partitioned among the phases. The thermophysical properties of the various mass components can be described at temperatures as low as -110 o C. Dissociation, phase changes and the corresponding thermal effects are fully described, as are the effects of salt and inhibitors. The model can describe all possible hydrate dissociation mechanisms, i.e., depressurization, thermal stimulation, salting-out effects and inhibitor-induced effects.Results are presented for four test problems of increasing complexity that explore different mechanisms and strategies for production from typical CH 4 -hydrate accumulations. The results of the tests indicate that CH 4 production from CH 4 -hydrates could be technically feasible and has significant potential. In particular, thermal stimulation is capable of producing substantial amounts of hydrocarbons, and its effectiveness can be enhanced when coupled with depressurization and the use of inhibitors.

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Section: Test Problemcontrasting

confidence: 58%

Section: Test Problemcontrasting

confidence: 58%

Section: Test Problemcontrasting

confidence: 55%

Section: Test Problemmentioning

confidence: 99%

Section: Test Problemmentioning

confidence: 99%

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Numerical Studies of Gas Production from Methane Hydrates

Moridis

2002

SPE Gas Technology Symposium

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Modelling and economic analysis of gas production from hydrates by depressurization method

Khataniar¹,

Kamath²,

Omenihu³

et al. 2002

Can J Chem Eng

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he estimates of natural gas within gas hydrate deposits worldwide are so large that they represent an unconventional source of T natural gas for the new millenium. The potential of gas hydrates as an unconventional gas resource is particularly attractive when one considers hydrates as a concentrated form of natural gas. Naturally occurring gas hydrates contain approximately 160-1 80 standard cubic metre (SCM) of gas per cubic metre of hydrates and have a composition of approximately 80-85 mol% water and 15-20 mol% gas. The gas within hydrates is predominantly methane. In terms of energy content, they are more similar to heavy oil and tar sand bitumen than to other unconventional gas resources. While hydrates contain 40-50 SCM of hydrated gas (42-53 MI) per cubic metre reservoir based on 30% porosity, coalbed methane contains 8-1 2, tight sands contain 5-1 0, Devonian Shale and geo-pressured aquifers contain only 1-2 SCM of gas per cubic metre of reservoir (Mutalik, 1989).Gas hydrates exist in reservoirs as relatively immobile and impermeable solids. The first step in production is to decompose gas hydrates into gas and water by various means. The process of hydrate decomposition requires that the heat of hydrate decomposition be provided to the decomposing hydrate surface in order to shift the equilibrium associated between hydrates, gas and water. Through energy balance calculations, it can be shown that the energy required for decomposition of gas hydrates into gas and water is approximately one-tenth of the energy value of the produced gas. This heat of decomposition is dependent upon the pressure, temperature, gas composition and concentration of inhibitor used, if any. Thus, the energy efficiency ratios (EER) in the range of 10 to 13 represent the highest that can be achieved in a most thermodynamically efficient process. Higher energy efficiency ratios are only possible with the use of inhibitor, which reduce the decomposition energy.Various methods of gas production from hydrates include depressurization, thermal stimulation and injection of inhibitors. The depressurization method is probably the most practical among these methods, however, it may be applicable to only those arctic and oceanic reservoirs that contain hydrates and associated free gas (Sira, 1991). In this method, the reservoir pressure is reduced below the three phase vapour-liquidhydrate equilibrium pressure, causing the hydrate to decompose. Heat required for decomposition of hydrate comes from the adjacent formations as a result of temperature gradient created by reduction in pressure, thereby eliminating heat losses, which can be significant in 'Author to whom correspondence may be addressed. E-mail address: ffsk@uaf.eduThe Canadl an Journal of Chemical Engi neeri ng, Volume 80. February 2002 Gas production from a hydrate reservoir involves decomposition of the solid hydrate. An analytical model is developed to predict reservoir performance for gas production by the depressurization method from a hydrate reservoir containing associated ...

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Experimental Studies on Techniques to Extract Natural Gas Hydrate

Liu

Sun

2012

Natural Gas Hydrates

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Simulation of Gas Production From a Reservoir Containing Both Gas Hydrates and Free Natural Gas

Cited by 45 publications

References 2 publications

Numerical Studies of Gas Production from Methane Hydrates

Numerical Studies of Gas Production from Methane Hydrates

Modelling and economic analysis of gas production from hydrates by depressurization method

Experimental Studies on Techniques to Extract Natural Gas Hydrate

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