Hydrate deposition prediction model for deep-water gas wells under shut-in conditions

Wang, Zhiyuan; Tong, Shikun; Wang, Chao; Zhang, Jianbo; Fu, Weiqi; Sun, Baojiang

doi:10.1016/j.fuel.2020.117944

Cited by 29 publications

(13 citation statements)

References 46 publications

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“…Numerous studies to-date have focused on the mechanisms of hydrate plugging in different oil–gas–water systems in pipelines, which is the key to economic risk management. − The experimental observations and theoretical analyses suggest that hydrate agglomeration and deposition are the two processes that cause hydrate plugging in oil and gas pipelines. In addition, hydrate deposition on a pipe wall can occur in two ways.…”

Section: Introductionmentioning

confidence: 99%

Effects of Solid Precipitation and Surface Corrosion on the Adhesion Strengths of Sintered Hydrate Deposits on Pipe Walls

et al. 2020

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A hydrate directly growing and sintering on a pipe wall is an important hydrate deposition case that has been relatively unexplored. In the present study, the adhesion strengths of a sintered cyclopentane (CyC5) hydrate deposit under different solid precipitation and surface corrosion conditions were measured and discussed. It was found that the hydrate adhesion strengths increased by 1.2–1.5× when the soaking time of the carbon steel substrate in a 5 wt % NaCl solution increased from 24 to 72 h, which reduced the water wetting angle from 112 ± 3.5° to 94 ± 3.3°. The wax coating reduced the strength of CyC5 hydrate adhesion by up to nearly 20-fold by reversing the substrate wettability and affecting the hydrate morphology. The measurements performed on scales indicate that calcium carbonate scales strengthen the adhesion strength because of the decrease in the water wetting angle. In addition, honeycomb holes on the surface reduce amplification. Furthermore, settling quartz sand on the wall reduced the adhesion strengths by decreasing the effective sintering area of the hydrate on the underlying base. Finer sand and higher concentrations led to lower strengths. On the basis of the verified linear correlation between the hydrate adhesion strength and the adhesion work of droplets on different substrates and the influence of water conversion during deposition, both an equation and a key constant parameter were obtained to predict the sintered hydrate deposit adhesion strengths on substrates.

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Section: Introductionmentioning

confidence: 99%

Effects of Solid Precipitation and Surface Corrosion on the Adhesion Strengths of Sintered Hydrate Deposits on Pipe Walls

et al. 2020

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“…In deepwater oil and gas transportation processes, natural gas hydrates can form easily in pipelines considering the suitable temperature and pressure conditions and therefore lead to pipeline plugging. − Up to now, hydrate prevention strategies have been widely investigated for deepwater flow assurance. − Recently, Wang et al ,, proposed a new strategy for hydrate management in deepwater well testing, which allows gas hydrate formation and deposition in the wellbore within a safe tolerance. According to their research, ,, the new strategy can save the usage of hydrate inhibitors beyond 50% and provide an important theoretical foundation for flow assurance in deepwater gas wells. In addition to hydrates, wax issues can also pose a great threat to deepwater flow assurance by precipitating out in the pipeline and depositing on the pipe wall .…”

Section: Introductionmentioning

confidence: 99%

“…7−10 Recently, Wang et al 2,8,9 proposed a new strategy for hydrate management in deepwater well testing, which allows gas hydrate formation and deposition in the wellbore within a safe tolerance. According to their research, 2,8,9 the new strategy can save the usage of hydrate inhibitors beyond 50% and provide an important theoretical foundation for flow assurance in deepwater gas wells. In addition to hydrates, wax issues can also pose a great threat to deepwater flow assurance by precipitating out in the pipeline and depositing on the pipe wall.…”

Section: Introductionmentioning

confidence: 99%

Investigation on Hydrate Growth at Oil–Water Interface: In the Presence of Wax

et al. 2021

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In deepwater oil and gas transportation processes, natural gas hydrates (NGHs) can form easily in pipelines considering the suitable temperature and pressure conditions and therefore lead to pipeline plugging. In water- and wax-containing oil systems, waxes can coexist with hydrates and thus contribute to even more severe challenges to deepwater pipeline flow assurance. In the present work, to investigate the effects of wax on hydrate growth at the oil–water interface, several micro experiments were performed in an atmospheric visual cell. According to the micro experimental phenomena, the morphology, porosity, wetness, and growth rate of the hydrate shell were studied and the effects of wax on hydrate growth were investigated. In experiments, two kinds of hydrate shells with different morphologies, porosities, and amounts of wetness were observed. Wax was found to have little effect on the morphology of the hydrate shell. However, wax molecules could remarkably influence the shape of the hydrate shell when the wax content ranged from 1 to 2 wt %. Moreover, wax molecules and crystals can influence the hydrate shell growth rate in terms of interfacial tension, medium concentration, mass/heat transfer resistance, and nucleation sites. The results in this work could provide guidance for hydrate management in wax-containing systems.

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“…Since 2014, CNOOC has started its own deep-water exploration in Qiongdongnan Basin of the South China Sea and made a historic breakthrough. However, due to the low temperature and high pressure near the mud line, and complex and changeable environment in deep water, the development of deep-water oil and gas fields faces the serious hydrate blockage problem in wellbore [2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Gas Hydrate Formation Risk and Prevention for the Development Wells in the Lingshui Gas Field in South China Sea

Jiang¹,

Yu²,

Huang³

et al. 2021

Geofluids

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Hydrate formation risk is an important challenge in the development of deep-water gas field. Considering the characteristics of the Lingshui (LS) gas field in the South China Sea and the difference of well structures, a model for calculating wellbore temperature and pressure in deep-water gas production well is proposed and verified by the field data. Combining the hydrate equilibrium models with varied gas components, the prediction method of hydrate formation region in deep-water gas well in the South China Sea is obtained. The hydrate formation regions under different operating conditions for a deep-water gas well in the South China Sea were given by the proposed model. The results show that no hydrate formation risk exists in the production operation, but the risk exists in the shut-in and testing operations. Meanwhile, the determination of the hydrate inhibitor injection parameters during the testing operation is studied, and the influence of the inhibitors’ injection concentration and pressure on preventing gas hydrates is analyzed. This work provides useful advice for the prediction and prevention of hydrate formation risk in the development of deep-water gas fields, especially in the South China Sea.

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Hydrate deposition prediction model for deep-water gas wells under shut-in conditions

Cited by 29 publications

References 46 publications

Effects of Solid Precipitation and Surface Corrosion on the Adhesion Strengths of Sintered Hydrate Deposits on Pipe Walls

Effects of Solid Precipitation and Surface Corrosion on the Adhesion Strengths of Sintered Hydrate Deposits on Pipe Walls

Investigation on Hydrate Growth at Oil–Water Interface: In the Presence of Wax

Gas Hydrate Formation Risk and Prevention for the Development Wells in the Lingshui Gas Field in South China Sea

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