scholarly journals Methane Production from Natural Gas Hydrates via Carbon Dioxide Fixation

2014 ◽  
Vol 61 ◽  
pp. 1776-1779 ◽  
Author(s):  
Ponnivalavan Babu ◽  
She Hern Bryan Yang ◽  
Somik Dasgupta ◽  
Praveen Linga
Keyword(s):  
Carbon Dioxide ◽  
Natural Gas ◽  
Gas Hydrates ◽  
Methane Production ◽  
Carbon Dioxide Fixation ◽  
Natural Gas Hydrates

MRI Visualization of Spontaneous Methane Production From Hydrates in Sandstone Core Plugs When Exposed to CO2

SPE Journal ◽  
2008 ◽  
Vol 13 (02) ◽  
pp. 146-152 ◽  
Author(s):  
Arne Graue ◽  
B. Kvamme ◽  
Bernie Baldwin ◽  
Jim Stevens ◽  
James J. Howard ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Methane Production ◽  
Methane Hydrate ◽  
Co2 Storage ◽  
Natural Gas Hydrate ◽  
Hydrate Dissociation ◽  
Natural Gas Hydrates ◽  
The Stability

Summary Magnetic resonance imaging (MRI) of core samples in laboratory experiments showed that CO2 storage in gas hydrates formed in porous rock resulted in the spontaneous production of methane with no associated water production. The exposure of methane hydrate in the pores to liquid CO2 resulted in methane production from the hydrate that suggested the exchange of methane molecules with CO2 molecules within the hydrate without the addition or subtraction of significant amounts of heat. Thermodynamic simulations based on Phase Field Theory were in agreement with these results and predicted similar methane production rates that were observed in several experiments. MRI-based 3D visualizations of the formation of hydrates in the porous rock and the methane production improved the interpretation of the experiments. The sequestration of an important greenhouse gas while simultaneously producing the freed natural gas offers access to the significant amounts of energy bound in natural gas hydrates and also offers an attractive potential for CO2 storage. The potential danger associated with catastrophic dissociation of hydrate structures in nature and the corresponding collapse of geological formations is reduced because of the increased thermodynamic stability of the CO2 hydrate relative to the natural gas hydrate. Introduction The replacement of methane in natural gas hydrates with CO2 presents an attractive scenario of providing a source of abundant natural gas while establishing a thermodynamically more stable hydrate accumulation. Natural gas hydrates represent an enormous potential energy source as the total energy corresponding to natural gas entrapped in hydrate reservoirs is estimated to be more than twice the energy of all known energy sources of coal, oil, and gas (Sloan 2003). Thermodynamic stability of the hydrate is sensitive to local temperature and pressure, but all components in the hydrate have to be in equilibrium with the surroundings if the hydrate is to be thermodynamically stable. Natural gas hydrate accumulations are therefore rarely in a state of complete stability in a strict thermodynamic sense. Typically, the hydrate associated with fine-grain sediments is trapped between low-permeability layers that keep the system in a state of very slow dynamics. One concern of hydrate dissociation, especially near the surface of either submarine or permafrost-associated deposits, is the potential for the release of methane to the water column or atmosphere. Methane represents an environmental concern because it is a more aggressive (~25 times) greenhouse gas than CO2. A more serious concern is related to the stability of these hydrate formations and its impact on the surrounding sediments. Changes in local conditions of temperature, pressure, or surrounding fluids can change the dynamics of the system and lead to catastrophic dissociation of the hydrates and consequent sediment instability. The Storegga mudslide in offshore Norway was created by several catastrophic hydrate dissociations. The largest of these was estimated to have occurred 7,000 years ago and was believed to have created a massive tsunami (Dawson et al. 1988). The replacement of natural gas hydrate with CO2 hydrate has the potential to increase the stability of hydrate-saturated sediments under near-surface conditions. Hydrocarbon exploitation in hydrate-bearing regions has the additional challenge to drilling operations of controlling heat production from drilling and its potential risk of local hydrate dissociation (Yakushev and Collett 1992). The molar volume of hydrate is 25-30% greater than the volume of liquid water under the same temperature-pressure conditions. Any production scenario for natural gas hydrate that involves significant dissociation of the hydrate (e.g., pressure depletion) has to account for the release of significant amounts of water that in turn affects the local mechanical stress on the reservoir formation. In the worst case, this would lead to local collapse of the surrounding formation. Natural gas production by CO2 exchange and sequestration benefits from the observation that there is little or no associated liquid water production during this process. Production of gas by hydrate dissociation can produce large volumes of associated water, and can create a significant environmental problem that would severely limit the economic potential. The conversion from methane hydrate to a CO2 hydrate is thermodynamically favorable in terms of free energy differences, and the phase transition is coupled to corresponding processes of mass and heat transport. The essential question is then if it is possible to actually convert methane hydrate as found in sediments to CO2 hydrate. Experiments that formed natural gas hydrates in porous sandstone core plugs used MRI to monitor the dynamics of hydrate formation and reformation. The paper emphasizes the experimental procedures developed to form the initial natural gas hydrates in sandstone pores and the subsequent exchange with CO2 while monitoring the dynamic process with 3D imaging on a sub millimetre scale. The in-situ imaging illustrates the production of methane from methane hydrate when exposed to liquid CO2 without any external heating.

scholarly journals The use of sodium chloride as strategy for improving CO2/CH4 replacement in natural gas hydrates promoted with depressurization methods

2020 ◽  
Vol 13 (18) ◽  
Author(s):  
Alberto Maria Gambelli ◽  
Federico Rossi
Keyword(s):  
Carbon Dioxide ◽  
Sodium Chloride ◽  
Natural Gas ◽  
Gas Hydrates ◽  
Hydrate Formation ◽  
Free Water ◽  
Process Efficiency ◽  
Natural Gas Hydrates ◽  
Replacement Process ◽  
Permanent Storage

Abstract Natural gas hydrates represent a valid opportunity in terms of energy supplying, carbon dioxide permanent storage and climate change contrast. Research is more and more involved in performing CO2 replacement competitive strategies. In this context, the inhibitor effect of sodium chloride on hydrate formation and stability needs to be investigated in depth. The present work analyses how NaCl intervenes on CO2 hydrate formation, comparing results with the same typology of tests carried out with methane, in order to highlight the influence that salt produced on hydrate equilibrium conditions and possibilities which arise from here for improving the replacement process efficiency. Sodium chloride influence was then tested on five CO2/CH4 replacement tests, carried out via depressurization. In relation with the same typology of tests, realised in pure demineralised water and available elsewhere in literature, three main differences were found. Before the replacement phase, CH4 hydrate formation was particularly contained; moles of methane involved were in the range 0.059–0.103 mol. On the contrary, carbon dioxide moles entrapped into water cages were 0.085–0.206 mol or a significantly higher quantity. That may be justified by the greater presence of space and free water due to the lower CH4 hydrate formation, which led to a more massive new hydrate structure formation. Moreover, only a small part of methane moles remained entrapped into hydrates after the replacement phase (in the range of 0.023–0.042 mol), proving that, in presence of sodium chloride, CO2/CH4 exchange interested the greater part of hydrates. Thus, the possibility to conclude that sodium chloride presence during the CO2 replacement process provided positive and encouraging results in terms of methane recovery, carbon dioxide permanent storage and, consequently, replacement process efficiency.

scholarly journals Experimental analysis of the CO2/CH4 Replacement Efficiency due to Sodium Chloride Presence in Natural Gas Hydrates Reservoirs

2020 ◽  
Vol 197 ◽  
pp. 08008
Author(s):  
Alberto Maria Gambelli ◽  
Beatrice Castellani ◽  
Mirko Filipponi ◽  
Andrea Nicolini ◽  
Federico Rossi
Keyword(s):  
Carbon Dioxide ◽  
Sodium Chloride ◽  
Natural Gas ◽  
Gas Hydrates ◽  
Energy Demand ◽  
Methane Molecule ◽  
Carbon Dioxide Molecule ◽  
Whole Process ◽  
Natural Gas Hydrates ◽  
Replacement Process

Nowadays natural gas hydrates represent a promising opportunity for counteracting several crucial issues of the 21th century. They are a valid answer to the continuously increasing energy demand, moved by the global population growth; moreover, considering their conformation and the possibility of using them for carbon dioxide permanently storage, gas hydrates may become a carbon neutral energy source, where for each methane molecule recovered, another carbon dioxide molecule is entrapped in solid form. Considering that the combustion of one methane molecule for energy production leads to the formation of one CO2 molecule, the hydrates exploitation can be considered a clean process in terms of impact on the climate change. This work shows how the presence of sodium chloride affects the CO2/CH4 replacement process into a gas hydrates reservoir. Replacement experimental results carried out in pure demineralised water were compared with the same values performed in a mixture of water and salt, having a concentration of 37 g/l. Some parameters of interest were discussed, such us methane hydrates formed before the replacement process, total amount of hydrates (composed by both species) reached at the end of the whole process, CO2 moles that formed hydrate, quantity of hydrate present before the replacement process which were actually involved in the CO2/CH4 exchange and carbon dioxide amount which led to the formation of new hydrates structures.

Research progress on methane production from natural gas hydrates

RSC Advances ◽  
2015 ◽  
Vol 5 (67) ◽  
pp. 54672-54699 ◽  
Author(s):  
Chun-Gang Xu ◽  
Xiao-Sen Li
Keyword(s):  
Natural Gas ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Methane Production ◽  
Research Progress ◽  
Production Methods ◽  
Natural Gas Hydrates ◽  
Hydrate Reservoirs ◽  
Methods Numerical ◽  
Field Production

A review of the research on methane production from gas hydrates, including the research on the characteristics of gas hydrate reservoirs, production methods, numerical simulations and field production tests.

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