scholarly journals A Thermodynamic Study of Methane Hydrates Formation In Glass Beads

2016 ◽  
Vol 16 (1) ◽  
pp. 15
Author(s):  
Tintin Mutiara ◽  
Budhijanto Budhijanto ◽  
I Made Bendiyasa ◽  
Imam Prasetyo
Keyword(s):  
Hydrogen Bonds ◽  
Gas Hydrates ◽  
Methane Hydrate ◽  
Hydrate Formation ◽  
Glass Beads ◽  
Water Molecules ◽  
Equilibrium Pressure ◽  
Natural Gas Hydrates ◽  
System Pressure ◽  
Energy Of Hydrogen Bonds

Natural gas hydrates are non-stoichiometry compounds, in which the molecules of gas are trapped in crystalline cells consisting of water molecules retained by energy of hydrogen bonds. The experiments of Methane hydrate formation are performed at constant temperature in a reactor filled with various sizes of glass beads and water. Methane gas was fed into the reactor at various initial pressures. Equilibrium condition was reached when the system pressure did not change. The experimental results showed that the size of the glass beads gave very small effect on the equilibrium pressure of methane hydrate formation, so the effect could be neglected. In this study, the equation of Langmuir constant was Ci,CH4=(1/RT)exp[A+(B/T)] with the values of A and B for small cages were 6.8465 and 18.0342. The values of A and B for large cages were 7.7598 and 18.0361

Quantification of methane hydrate formation in the Large-scale Reservoir Laboratory Simulator (LARS) by numerical simulations

2021 ◽  
Author(s):  
Zhen Li ◽  
Thomas Kempka ◽  
Erik Spangenberg ◽  
Judith Schicks
Keyword(s):  
Gas Hydrates ◽  
Methane Hydrate ◽  
Large Scale ◽  
Hydrate Formation ◽  
Simulation Environment ◽  
Transport Simulation ◽  
Chemistry Research ◽  
Research Activities ◽  
In Situ Conditions ◽  
Hydrate Bearing Sediments

<p>Natural gas hydrates are considered as one of the most promising alternatives to conventional fossil energy sources, and are thus subject to world-wide research activities for decades. Hydrate formation from methane dissolved in brine is a geogenic process, resulting in the accumulation of gas hydrates in sedimentary formations below the seabed or overlain by permafrost. The LArge scale Reservoir Simulator (LARS) has been developed (Schicks et al., 2011, 2013; Spangenberg et al., 2015) to investigate the formation and dissociation of gas hydrates under simulated in-situ conditions of hydrate deposits. Experimental measurements of the temperatures and bulk saturation of methane hydrates by electrical resistivity tomography have been used to determine the key parameters, describing and characterising methane hydrate formation dynamics in LARS. In the present study, a framework of equations of state to simulate equilibrium methane hydrate formation in LARS has been developed and coupled with the TRANsport Simulation Environment (Kempka, 2020) to study the dynamics of methane hydrate formation and quantify changes in the porous medium properties in LARS. We present our model implementation, its validation against TOUGH-HYDRATE (Gamwo & Liu, 2010) and the findings of the model comparison against the hydrate formation experiments undertaken by Priegnitz et al. (2015). The latter demonstrates that our numerical model implementation is capable of reproducing the main processes of hydrate formation in LARS, and thus may be applied for experiment design as well as to investigate the process of hydrate formation at specific geological settings.</p><p>Key words: dissolved methane; hydrate formation; hydration; python; permeability.</p><p>References</p><p>Schicks, J. M., Spangenberg, E., Giese, R., Steinhauer, B., Klump, J., & Luzi, M. (2011). New approaches for the production of hydrocarbons from hydrate bearing sediments. Energies, 4(1), 151-172, https://doi.org/10.3390/en4010151</p><p>Schicks, J. M., Spangenberg, E., Giese, R., Luzi-Helbing, M., Priegnitz, M., & Beeskow-Strauch, B. (2013). A counter-current heat-exchange reactor for the thermal stimulation of hydrate-bearing sediments. Energies, 6(6), 3002-3016, https://doi.org/10.3390/en6063002</p><p>Spangenberg, E., Priegnitz, M., Heeschen, K., & Schicks, J. M. (2015). Are laboratory-formed hydrate-bearing systems analogous to those in nature?. Journal of Chemical & Engineering Data, 60(2), 258-268, https://doi.org/10.1021/je5005609</p><p>Kempka, T. (2020) Verification of a Python-based TRANsport Simulation Environment for density-driven fluid flow and coupled transport of heat and chemical species. Adv. Geosci., 54, 67–77, https://doi.org/10.5194/adgeo-54-67-2020</p><p>Gamwo, I. K., & Liu, Y. (2010). Mathematical modeling and numerical simulation of methane production in a hydrate reservoir. Industrial & Engineering Chemistry Research, 49(11), 5231-5245, https://doi.org/10.1021/ie901452v</p><p>Priegnitz, M., Thaler, J., Spangenberg, E., Schicks, J. M., Schrötter, J., & Abendroth, S. (2015). Characterizing electrical properties and permeability changes of hydrate bearing sediments using ERT data. Geophysical Journal International, 202(3), 1599-1612, https://doi.org/10.1093/gji/ggv245</p>

scholarly journals Effect of the THF molecules on the hydrate cavities formation with adding NaCL molecules into the modeling system

2021 ◽  
Vol 2057 (1) ◽  
pp. 012077
Author(s):  
Y Y Bozhko ◽  
R K Zhdanov ◽  
K V Getz ◽  
V R Belosludov
Keyword(s):  
Hydrogen Bonds ◽  
Guest Molecule ◽  
Hydrate Formation ◽  
Water Molecules ◽  
Torsion Angles ◽  
Simulated System ◽  
Thermodynamic Conditions ◽  
Different Temperatures ◽  
Molecular Dynamics Methods ◽  
Simulation Time

Abstract In this work, using molecular dynamics methods by Gromacs package we simulate the hydrate formation in systems containing THF, water, and NACL molecules at different thermodynamic conditions and concentration of THF molecules. The curves of the number of hydrogen bonds are obtained depending on the simulation time at different temperatures. The computer simulations results show that the hydrogen bonds between THF and water molecules are relatively weak, with a maximum number of two water molecules hydrogen bonded to THF, but THF can facilitate water molecules rearrangement to form a pentagonal or hexagonal planar ring that is the part of clathrate cavity. In addition, the THF molecule can significantly increase the likelihood to form clathrate cavities suitable for the second guest molecule. The effect of THF molecules concentration on the hydrate cavities formation with adding NaCL molecules into the modeling system is shown. In this work, data are obtained on the magnitude of torsion angles, the percentage of which increases depending on the simulation time, which allows concluding that labile large and small cavities of sII hydrates are formed. The increase in the THF molecules concentration is shown to lead to a decrease in the hydrogen bonds number of water molecules in the simulated system.

Experimental Investigation of Methane Hydrate Formation in the Carboxmethylcellulose (CMC) Aqueous Solution

SPE Journal ◽  
2020 ◽  
Vol 25 (03) ◽  
pp. 1042-1056 ◽  
Author(s):  
Weiqi Fu ◽  
Zhiyuan Wang ◽  
Litao Chen ◽  
Baojiang Sun
Keyword(s):  
Aqueous Solution ◽  
Mass Transfer ◽  
Gas Hydrates ◽  
Methane Hydrate ◽  
Formation Rate ◽  
Hydrate Formation ◽  
Semiempirical Model ◽  
Stirred Reactor ◽  
Proposed Model ◽  
Wellbore Pressure

Summary In the development of deepwater crude oil, gas, and gas hydrates, hydrate formation during drilling operations becomes a crucial problem for flow assurance and wellbore pressure management. To study the characteristics of methane hydrate formation in the drilling fluid, the experiments of the methane hydrate formation in water with carboxmethylcellulose (CMC) additive are performed in a horizontal flow loop under flow velocity from 1.32 to 1.60 m/s and CMC concentration from 0.2 to 0.5 wt%. The flow pattern is observed as bubbly flow in experiments. The experiments indicate that the increase of CMC concentration impedes the hydrate formation while the increase of liquid velocity enhances formation rates. In the stirred reactor, the hydrate formation rate generally decreases as the subcooling condition decreases. However, in this work, with the subcooling condition continuously decreasing, hydrate formation rate follows a “U” shaped trend—initially decreasing, then leveling out and finally increasing. It is because the hydrate formation rate in this work is influenced by multiple factors, such as hydrate shell formation, fracturing, sloughing, and bubble breaking up, which has more complicated mass transfer procedure than that in the stirred reactor. A semiempirical model that is based on the mass transfer mechanism is developed for current experimental conditions, and can be used to predict the formation rates of gas hydrates in the non-Newtonian fluid by replacing corresponding correlations. The rheological experiments are performed to obtain the rheological model of the CMC aqueous solution for the proposed model. The overall hydrate formation coefficient in the proposed model is correlated with experimental data. The hydrate formation model is verified and the predicted quantity of gas hydrates has a discrepancy less than 10%.

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 Advances in the Study of Gas Hydrates by Dielectric Spectroscopy

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4459
Author(s):  
Ivan Lunev ◽  
Bulat Kamaliev ◽  
Valery Shtyrlin ◽  
Yuri Gusev ◽  
Airat Kiiamov ◽  
...  
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Dielectric Spectroscopy ◽  
Relaxation Times ◽  
Hydrate Formation ◽  
Water Molecules ◽  
Natural Gas Hydrate ◽  
Real Component ◽  
Local Structures ◽  
Gas Hydrate Formation

The influence of kinetic hydrate inhibitors on the process of natural gas hydrate nucleation was studied using the method of dielectric spectroscopy. The processes of gas hydrate formation and decomposition were monitored using the temperature dependence of the real component of the dielectric constant ε′(T). Analysis of the relaxation times τ and activation energy ΔE of the dielectric relaxation process revealed the inhibitor was involved in hydrogen bonding and the disruption of the local structures of water molecules.

scholarly journals Hydrate Equilibrium Modelling with the Cubic two-state Equation of State

2017 ◽  
Vol 60 (4) ◽  
Author(s):  
Edgar Galicia-Andrés ◽  
Milton Medeiros
Keyword(s):  
Equation Of State ◽  
Gas Hydrates ◽  
Hydrate Formation ◽  
Triethylene Glycol ◽  
State Equation ◽  
Model Parameters ◽  
Equilibrium Pressure ◽  
Multicomponent Gas ◽  
Pure Compounds ◽  
Equilibrium Data

A combination of the cubic two-state equation of state and the van der Waals–Platteeuw model was employed for the description of the hydrate formation thermodynamics, with and without inhibitors. The model parameters were determined from the properties of pure compounds and from phase equilibrium data of binary gas–water and water–inhibitor mixtures. With these parameters, predictions were performed for multicomponent gas–water–inhibitor systems. For single-gas hydrates, the average absolute deviations found for equilibrium pressure did not exceed 8%, whereas for multi-gas hydrates, these deviations were 23% maximum. The proposed model produced good predictions in the presence of inhibitors (methanol, ethanol, ethylene glycol and triethylene glycol), with increasing deviations at higher concentrations of inhibitors.

scholarly journals Clathrate Ices—Recent Results

1978 ◽  
Vol 21 (85) ◽  
pp. 33-49
Author(s):  
D. W. Davidson ◽  
J. A. Ripmeester
Keyword(s):  
Natural Gas ◽  
Ethylene Oxide ◽  
Gas Hydrates ◽  
Time Scale ◽  
Water Molecules ◽  
Guest Molecules ◽  
Natural Gas Hydrates ◽  
Change Effect ◽  
Line Narrowing ◽  
Permafrost Regions

AbstractThe last five years have seen an increasing interest in clathrate ices as a result of the discovery of extensive deposits of natural gas hydrates in permafrost regions. Twenty-six new clathrate hydrates have been identified, mainly by NMR, including a tetragonal hydrate of dimethyl ether. N-butane and neopentane have been found to be enclathrated in natural gas hydrates, the former as a gauche conformer. As a result of their high symmetries, encaged neopentane, CF4, SF6, and SeF6 exhibit a Resing apparent-phase-change effect in the temperature range of NMR line narrowing. There is increasing evidence that reorientational jumps of water molecules are more frequent than translational jumps in clathrate ices. This is certainly so for ethylene oxide-d4 and tetrahydrofuran-d8 hydrates for which two regions of proton line narrowing and two T1ρ minima have been observed. The reorientational motions of most guest molecules in structure II hydrates only become isotropic on a time scale long enough to permit the cage configurations to be averaged to 43m symmetry by reorientation of the water molecules. The orientations of the water molecules remain disordered to the lowest temperatures.

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 A Case Study Of Natural Gas Hydrates (NGH) In Offshore NW Sabah: Identification, Shallow Geohazard Implication For Exploration Drilling, Extraction Challenges And Potential Energy Resource Estimation

2020 ◽  
Vol 70 (1) ◽  
pp. 57-75
Author(s):  
John Jong ◽  
◽  
Hui Sin Goh ◽  
Steve McGiveron ◽  
Jim Fitton ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Natural Gas ◽  
Gas Hydrates ◽  
Energy Resource ◽  
Water Molecules ◽  
Low Molecular Weight ◽  
Natural Gas Hydrates ◽  
Exploration Drilling ◽  
Methane Gas Hydrates

Natural gas hydrates (NGHs), sometimes referred to as “flammable ice”, are crystalline solids, consisting of hydrocarbon gases with low molecular weight, such as methane, ethane and propane, bound with water molecules within cage-like lattices. The water molecules and low molecular weight NGH lattices are stable within a specific range of temperatures and pressures, and the source of the gases can be biogenic or thermogenic in origin. NGHs are common in the upper hundreds of metres of sub-seafloor sediments on the continental margins at water depths greater than about 500 m. Seismic reflection profiles and wireline well logs are common indicators used to identify the presence of NGHs, which are often encountered during offshore deepwater exploration drilling. They may cause geohazards such as slope instability, expulsion of the seafloor, shallow water flows and shallow gas if the stability of penetrated NGHs is disturbed and starts to dissociate. Methane gas hydrates represent a significant potential energy resource, as illustrated in this case study from offshore NW Sabah and may represent one of the world’s largest reservoirs of carbon-based fuel, with some estimates suggest that the hydrocarbons bound in the form of NGHs may rival the total energy resources contained in other conventional hydrocarbon sources. Methane can be extracted from NGHs through three methods: depressurization, inhibitor injection and thermal stimulation. However, risk associated with NGHs extraction can contribute to environmental concerns such as global warming and a decrease in microbial communities associated with methane hydrate ecosystem. Presently, in many countries, national programs exist for the research and production of natural gas from NGH deposits. As a result, hundreds of deposits have been discovered, with a few hundred wells drilled and kilometres of NGH cores studied. Hence, in the future (pending improved gas price and extraction technology), methane gas hydrates could be a vast source of natural gas supply.

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