Experimental and modeling investigations into hydrate shell growth on suspended bubbles considering pore updating and surface collapse

Deep ocean bubble transport model coupled with multiple hydrate behavior characteristics

“…Their high‐resolution photographic data reveal that bubble migration inside the GHSZ is frequently accompanied by surface collapses or fractures. These hydrate behavior characteristics were later confirmed in recent experiments 26–28 . With respect to the controlling mechanism of hydrate growth, Davies et al 29 and Zeng et al 30 carried out in situ investigations into the hydrate thickening growth process and its interior mass‐transfer channels using optical microscopy and confocal Raman spectroscopy.…”

“…Subsequently, the interfacial wave oscillations disappear because the shell has certain strength to resist the underlying deformation caused by the surrounding flow water. 28 Although the porous shell effectively separates the bubble from liquid water, the intergranular pores in the hydrate provide special pathways for the transport of gas or water molecules promoting hydrate formation or bubble dissolution 29,34 (Figure 1D). As hydrate shell grows thicker, the interior micro-pore structure is constantly compacted, becoming denser.…”

“…However, in both stages III and IV, the solid hydrate coating can alter the mechanical properties of the bubble interface, thereby providing certain anti-deformation capacity to resist potential shrinkage. 27,28 In particular, when the strength of the shell provides insufficient resistance against the stress caused by the pressure difference between the interior and exterior of the bubble, the hydrate-coated bubble may collapse or rupture. In this case, the bubble shrinkage behavior is not only related to the concentration driving force, but also depends on the critical bearing pressure of the hydrate coating.…”

“…Moreover, owing to the limitations of field experimental conditions and operations, further details of the hydrate behavior characteristics of a rising bubble in water can be identified only by laboratory experiments. [23][24][25][26][27][28][29][30][31][32] Peng et al 23 conducted a series of static experiments on the lateral and vertical growth of hydrates on suspended methane bubbles. These suggest that the rate of lateral hydrate spread is considerably higher than the rate of hydrate thickening growth.…”

“…These hydrate behavior characteristics were later confirmed in recent experiments. [26][27][28] With respect to the controlling mechanism of hydrate growth, Davies et al 29 and Zeng et al 30 carried out in situ investigations into the hydrate thickening growth process and its interior mass-transfer channels using optical microscopy and confocal Raman spectroscopy. It was found that hydrates can also form in the intergranular pores, as well as on both sides of the hydrate shell.…”