Behaviors of CH4 hydrate formation in cold seeps with underlying gas plume

Guo, Xianwei; Shi, Kangji; Guan, Dawei; Lv, Xiaoyi; Li, Qingping; Dong, Hongsheng; Zhao, Jiafei; Yang, Lei; Liu, Zheyuan

doi:10.1016/j.fuel.2021.121364

Cited by 10 publications

(11 citation statements)

References 38 publications

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“…Marine deposits and permafrost are the main locations of natural gas hydrate formation [23]. This involves a complex process of nucleation and hydrate accumulation in deposition matrices [24]. In the natural world, gas hydrates are usually dispersed in the pores of coarse-grained sediment [74].…”

Section: Formation and Dissociation Of Gas Hydratesmentioning

confidence: 99%

“…The formation of gas hydrates associated with cold seeps was detected at many locations, such as at the seafloor of the South China Sea [83] and in sedimentary basins of Brazil [27] and New Zealand [84]. Guo et al [24] found that the initial hydrate formation can proceed throughout sedimentary matrices as a result of a substantial contact of gas with water in the gas flow. In particular, the appreciable quantity of heat released from the Specific aspects of gas hydrate formation in different media were discussed in References [23,74,[80][81][82].…”

Section: Formation and Dissociation Of Gas Hydratesmentioning

confidence: 99%

“…This confirms the decisive sufficient gas-water contact role in the formation of gas hydrate. Still, a great amount of residual water remains right to the end of the formation process [24].…”

Section: Formation and Dissociation Of Gas Hydratesmentioning

confidence: 99%

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Key Areas of Gas Hydrates Study: Review

2022

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Gas hydrates are widespread all over the world. They feature high energy density and are a clean energy source of great potential. The paper considers experimental and theoretical studies on gas hydrates in the following key areas: formation and dissociation, extraction and transportation technologies of natural methane hydrates, and ignition, and combustion. We identified a lack of research in more areas and defined prospects of further development of gas hydrates as a promising strategic resource. One of the immediate problems is that there are no research findings for the effect of sediments and their matrices on hydrate saturation, as well as on gas hydrate formation and dissociation rates. No mathematical models describe the dissociation of gas hydrates under various conditions. There is a lack of research into the renewal and improvement of existing technologies for the easier and cheaper production of gas hydrates and the extraction of natural gas from them. There are no models of gas hydrate ignition taking into account dissociation processes and the self-preservation effect.

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Section: Formation and Dissociation Of Gas Hydratesmentioning

confidence: 99%

Section: Formation and Dissociation Of Gas Hydratesmentioning

confidence: 99%

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Key Areas of Gas Hydrates Study: Review

2022

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“…31 At the same time, researchers in the laboratory also carried out related hydrate crystal morphology and dynamics experiments by observing CH 4 bubbles rising in a simulated oceanic environment. 32 Moreover, in the aspect of hydrate-based technology for natural gas storage, it is also the focus of current energy storage research to seek more efficient promotion additives and speed up hydrate generation and conversion efficiency. Experimental studies on the kinetics of the bubble method to promote hydrate formation have also been carried out successively.…”

Section: Introductionmentioning

confidence: 99%

“…Researchers have also found that hydrates will form rapidly at the bubble interface through seafloor observation devices. − Moreover, the process of hydrate shell formation alters the fate of methane that naturally bubbles up from the seafloor and then slow down bubble dissolution and gas exchange, allowing more methane to be delivered to shallower water depths, which contributes to a number of benthic, water column, and atmospheric processes even climate change . At the same time, researchers in the laboratory also carried out related hydrate crystal morphology and dynamics experiments by observing CH 4 bubbles rising in a simulated oceanic environment . Moreover, in the aspect of hydrate-based technology for natural gas storage, it is also the focus of current energy storage research to seek more efficient promotion additives and speed up hydrate generation and conversion efficiency.…”

Section: Introductionmentioning

confidence: 99%

Morphology Study of Hydrate Shell Crystal Growth on a Microbubble Interface in the Presence of Additives

Kuang

Zheng

Dai

et al. 2023

Crystal Growth & Design

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Bubble dispersions in water can be observed in both wellbore or subsea piping as well as subsea gas seepages. The hydrate risk in subsea pipelines or methane leaks from the cold spring into seawater can be strongly influenced by the hydrate crystal growth on bubbles. In addition, the bubbling method has been proven to be an effective method to enhance the gas–liquid mixing pathway and promote hydrate’s rapid formation in the application of hydrate-based technologies, yet the microscopic mechanism of hydrate film growth on the bubbles still needs to be further clarified. In this study, the hydrate crystal growth morphology evolution at the microbubble interface was investigated by a high-resolution microscope combined with the temperature-controlled stage. The results showed that the hydrate crystals nucleated rapidly at the bubble interface to form a hydrate shell-coated structure in a pure water system. The defect growth mechanism dominated the hydrate crystals growth at the bubble interface in additive solutions. Hydrate did not nucleate directly on the surface of bubbles but by trapping guest molecules around the shrinking bubbles to form aggregated hydrate agglomeration in the presence of surfactants. In addition, the bubbles tend to provide a steady stream of gas source for hydrate formation. The growth of hydrate shells contributed to a normal distribution of bubble shrinking rates, with an average rate of 9 μm/s in 0.5 wt % NaCl solution. The existence of a high concentration of ions or organic molecules at the microbubbles’ interface and the exclusive effect played a dominant role in the process of hydrate formation. In addition, it was found that the repulsive effect of ions at the bubble interface on hydrate formation was weak under a high subcooling degree. However, other organic molecule promoters still accelerated the hydrate’s formation rate because they increased the dissolution and diffusion rate of gas in solution. The results are expected to strengthen further the applications relating to hydrate-based phase transition promotion technology in the industry in energy storage, gas separation, or inhibition techniques in flow assurance of the offshore industry.

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