A Review of the Methane Hydrate Program in Japan

Oyama, Ai; Masutani, Stephen M.

doi:10.3390/en10101447

Cited by 64 publications

(25 citation statements)

References 17 publications

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“…Officially, the reasons were massive sand production and reservoir freezing. The second test [17] was supposed to last for 6 months but the sediments froze after 24 days [17][18][19].…”

Section: Small Alcohols As Surfactants In Hydrate Productionmentioning

confidence: 99%

Small Alcohols as Surfactants and Hydrate Promotors

Kvamme

2021

Fluids

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Many methods to produce hydrate reservoirs have been proposed in the last three decades. Thermal stimulation and injection of thermodynamic hydrate inhibitors are just two examples of methods which have seen reduced attention due to their high cost. However, different methods for producing hydrates are not evaluated thermodynamically prior to planning expensive experiments or pilot tests. This can be due to lack of a thermodynamic toolbox for the purpose. Another challenge is the lack of focus on the limitations of the hydrate phase transition itself. The interface between hydrate and liquid water is a kinetic bottle neck. Reducing pressure does not address this problem. An injection of CO2 will lead to the formation of a new CO2 hydrate. This hydrate formation is an efficient heat source for dissociating hydrate since heating breaks the hydrogen bonds, directly addressing the problem of nano scale kinetic limitation. Adding limited amounts of N2 increases the permeability of the injection gas. The addition of surfactant increases gas/water interface dynamics and promotes heterogeneous hydrate formation. In this work we demonstrate a residual thermodynamic scheme that allows thermodynamic analysis of different routes for hydrate formation and dissociation. We demonstrate that 20 moles per N2 added to the CO2 is thermodynamically feasible for generating a new hydrate into the pores. When N2 is added, the available hydrate formation enthalpy is reduced as compared to pure CO2, but is still considered sufficient. Up to 3 mole percent ethanol in the free pore water is also thermodynamically feasible. The addition of alcohol will not greatly disturb the ability to form new hydrate from the injection gas. Homogeneous hydrate formation from dissolved CH4 and/or CO2 is limited in amount and not important. However, the hydrate stability limits related to concentration of hydrate former in surrounding water are important. Mineral surfaces can act as hydrate promotors through direct adsorption, or adsorption in water that is structured by mineral surface charges. These aspects will be quantified in a follow-up paper, along with kinetic modelling based on thermodynamic modelling in this work.

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“…Officially, the reasons were massive sand production and reservoir freezing. The second test [17] was supposed to last for 6 months but the sediments froze after 24 days [17][18][19].…”

Section: Small Alcohols As Surfactants In Hydrate Productionmentioning

confidence: 99%

Small Alcohols as Surfactants and Hydrate Promotors

Kvamme

2021

Fluids

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“…The Nankai Trough production tests used the "Chikyu (Earth)" deep ocean drilling vessel and a Japanese gas-liquid separator. Both these systems proved effective during the respective production tests [64,65]. During the drilling of these production wells, drilling fluids had significant quantities of thermodynamic inhibitors added to the drilling mud to suppress or retard the regeneration of hydrates.…”

Section: Drilling Technology Managementmentioning

confidence: 99%

“…tests [64,65]. During the drilling of these production wells, drilling fluids had significant quantities of thermodynamic inhibitors added to the drilling mud to suppress or retard the regeneration of hydrates.…”

Section: Drilling Technology Managementmentioning

confidence: 99%

Prevention of Potential Hazards Associated with Marine Gas Hydrate Exploitation: A Review

Wang

Zhao

2018

Energies

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Marine gas hydrates (MGHs), which have great potential for exploitation and utilization, account for around 99% of all global natural gas hydrate resources under current prospecting technique. However, there are several potential hazards associated with their production and development. These are classified into four categories by this paper: marine geohazards, greenhouse gas emissions, marine ecological hazards, and marine engineering hazards. In order to prevent these risks from occurring, the concept of "lifecycle management of hazards prevention" during the development and production from MGHs is proposed and divided into three stages: preparation, production control, and post-production protection. Of these stages, economic evaluation of the resource is the foundation; gas production methods are the key; with monitoring, assessment, and early warning as the guarantee. A production test in the Shenhu area of the South China Sea shows that MGH exploration and development can be planned using the "three-steps" methodology: commercializing and developing research ideas in the short term, maintaining economic levels of production in the medium term, and forming a global forum to discuss effective MGH development in the long term. When increasing MGH development is combined with the lifecycle management of hazards prevention system, and technological innovations are combined with global cooperation to solve the risks associated with MGH development, then safe access to a new source of clean energy may be obtained.

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“…During the past three decades, marine natural gas hydrates have increasingly gained attention. Depending on the focus of consideration, they are either regarded as a potential unconventional resource of natural gas [2][3][4], a potential hazard due to their global warming-induced dissociation whereby the potent greenhouse gas CH 4 is released and the geomechanical stability of the seafloor is weakened [5], or as a means to store CO 2 as an immobile mineral [6] A much-discussed strategy for tackling the aforementioned three aspects of natural-gas production, carbon-dioxide sequestration, and geohazard mitigation, is the in situ exchange of the guest molecule CH 4 with the guest molecule CO 2 [7], hereafter termed gas exchange. The swapping of the two molecules is thermodynamically favored [8,9], takes place spontaneously, and has several benefits:…”

Section: Introductionmentioning

confidence: 99%

Microscale Processes and Dynamics during CH4–CO2 Guest-Molecule Exchange in Gas Hydrates

et al. 2021

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The exchange of CH4 by CO2 in gas hydrates is of interest for the production of natural gas from methane hydrate with net zero climate gas balance, and for managing risks that are related to sediment destabilization and mobilization after gas-hydrate dissociation. Several experimental studies on the dynamics and efficiency of the process exist, but the results seem to be partly inconsistent. We used confocal Raman spectroscopy to map an area of several tens to hundreds µm of a CH4 hydrate sample during its exposure to liquid and gaseous CO2. On this scale, we could identify and follow different processes in the sample that occur in parallel. Next to guest-molecule exchange, gas-hydrate dissociation also contributes to the release of CH4. During our examination period, about 50% of the CO2 was bound by exchange for CH4 molecules, while the other half was bound by new formation of CO2 hydrates. We evaluated single gas-hydrate grains with confirmed gas exchange and applied a diffusion equation to quantify the process. Obtained diffusion coefficients are in the range of 10−13–10−18 m2/s. We propose to use this analytical diffusion equation for a simple and robust modeling of CH4 production by guest-molecule exchange and to combine it with an additional term for gas-hydrate dissociation.

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A Review of the Methane Hydrate Program in Japan

Cited by 64 publications

References 17 publications

Small Alcohols as Surfactants and Hydrate Promotors

Small Alcohols as Surfactants and Hydrate Promotors

Prevention of Potential Hazards Associated with Marine Gas Hydrate Exploitation: A Review

Microscale Processes and Dynamics during CH4–CO2 Guest-Molecule Exchange in Gas Hydrates

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