Investigating hydrate formation rate and the viscosity of hydrate slurries in water-dominant flow: Flowloop experiments and modelling

Sakurai, Shunsuke; Hoskin, Ben; Choi, Joel; Nonoue, Tomoya; May, Eric F.; Kumar, Asheesh; Norris, Bruce; Aman, Zachary M.

doi:10.1016/j.fuel.2021.120193

Cited by 26 publications

(15 citation statements)

References 51 publications

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“…For water-dominant systems, Joshi et al proposed a conceptual picture including the following three steps: (i) hydrate formation at the gas–water–wall interface; (ii) transition of the hydrate particle distribution from homogeneous to heterogeneous; and (iii) hydrate bedding leading to blockage. Recently, experimental studies with flowloops have started to examine the details of this conceptual picture, − but these have not generally discussed hydrate bedding and blockage.…”

Section: Introductionmentioning

confidence: 99%

Behavior of Methane Hydrate-in-Water Slurries from Shut-in to Flow Restart

Sakurai

Hoskin²,

Choi³

et al. 2021

Energy Fuels

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Natural gas hydrates have attracted interest as a potential future energy resource to meet the expected growth in the global energy demand. One of the key challenges to be tackled for commercial production is gas hydrate re-formation in production lines. Such hydrate blockages have been a major concern of flow assurance in the oil and gas industries, and typically occur during start-up, shut-in, and restart operations. This study sheds light on the behavior of methane hydrate slurries in pure water systems under shut-in conditions and their transition to solid blockages during system restart: a key risk factor in gas hydrate production. Flowloop experiments were conducted to measure the critical stress required to restart flow in hydrate slurries, which were accompanied by visual observations using an in-line video camera. A transition from smooth restart to a critical stress requirement was observed at 4−5 vol % of hydrate; visually, this corresponded to complete occupancy of the flow cross section with porous aggregated hydrate particles in a loosely packed network. The critical stress increased with higher hydrate volume fractions per the behavior of yield stress for a general suspension: it was not affected by the shut-in period, suggesting that annealing was not a factor at the volume fractions measured. Further, hydrate blockage occurred in several restart operations at approximately 18 vol % of hydrate even though the video camera had captured partial yielding before the blockage occurred. These results show a progression in slurry behavior as a function of hydrate volume fraction, offering insights into varied mechanisms for blockage formation, and operational strategies to minimize blockage risk.

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Section: Introductionmentioning

confidence: 99%

Behavior of Methane Hydrate-in-Water Slurries from Shut-in to Flow Restart

Sakurai

Hoskin²,

Choi³

et al. 2021

Energy Fuels

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“…In low temperatures and high pressures, the water molecules formed cage-like structures by the hydrogen bonds to restrict the lightweight methane molecules. − Methane hydrate is widely distributed in the submarine sediment and permafrost regions . It is estimated that about 27% of marine areas and 90% of land are potential areas for methane hydrate formation. , Methane hydrate is considered a high-density energy source because 1 volume of methane hydrate decomposition can release about 164 volumes of methane gas under standard conditions. , Moreover, the pollutants and harmful substances produced by the combustion of methane hydrate are much less than those of conventional fossil energy sources. − Therefore, methane hydrate is deemed as a new environment-friendly energy to deal with the increase in global energy demand. − …”

Section: Introductionmentioning

confidence: 99%

Spatial Distribution and Phase Transition Characteristics of Methane Hydrate in the Water-Excess and Gas-Excess Deposits

Zhang,

Sun,

et al. 2024

Energy Fuels

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Methane hydrate is considered as a new environmentally friendly energy to meet future society development. To achieve safe and efficient hydrate production, it is critical to understand the hydrate accumulation characteristics in different deposits, considering the geological feature differences. In this study, the hydrate distribution characteristics in the gas-excess and water-excess deposits were visually investigated by using magnetic resonance imaging technology. Moreover, the effect of the initial gas pressure on hydrate formation behaviors and stability was analyzed. The results showed that methane hydrate first formed in the water–gas interface for the water-excess deposit, and then, the hydrate formation front gradually expanded into the water phase accumulation area. Moreover, the methane hydrate distribution was mainly determined by the initial distribution of water and gas in the porous media. For the water-excess deposit, the spatial distribution of methane hydrate showed an obvious heterogeneity, and the mass hydrate accumulated at the bottom of the deposit. However, a uniform distribution of methane hydrate in the gas-excess deposit was observed. Furthermore, methane hydrate that formed in the higher initial gas pressure and the water-excess environment had good stability during the water flow process, which prolonged the duration of the hydrate decomposition process. The findings attempt to provide valuable information and guidelines for understanding the gas hydrate system.

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“…While there are opportunities to improve the economic feasibility of the offshore gas field by reducing the THIs amount, the consequences of pipeline plugging during operations in underinhibited conditions could be severe. Therefore, it is vital to understand the hydrate plugging risk/behavior in underinhibition conditions for various oil–gas–water systems. − Though a significant development has been made toward elucidating hydrate formation and deposition mechanisms in oil-dominant pipelines, gas- or water-dominant systems are the least well-studied and understood. ,− …”

Section: Introductionmentioning

confidence: 99%

“…Further, based on experiments conducted in a flow loop simulator (rotating wheel) with oil-dominated systems and underinhibited MEG, Hemmingsen et al discussed a conceptual model that can estimate the plugging potential of underinhibited systems based on agglomeration phenomena driven by capillary adhesion forces. − They concluded that MEG at a concentration of <20 wt % can increase the likelihood of forming sticky hydrate particles, leading to increased plugging risk. Di Lorenzo et al also investigated the effect of MEG underinhibition (0–40 wt %) on hydrate formation and transportability in gas-dominated systems employing a single-pass flow loop .…”

Section: Introductionmentioning

confidence: 99%

Elucidating the Impact of Thermodynamic Hydrate Inhibitors and Kinetic Hydrate Inhibitors on a Complex System of Natural Gas Hydrates: Application in Flow Assurance

et al. 2023

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To alleviate the hydrate blockage risk in oil and gas pipelines/production facilities, thermodynamic hydrate inhibitors (THIs) and kinetic hydrate inhibitors (KHIs) are the frequently used additives/chemicals. While these additives are highly effective, the impact of low dosage of THIs (under inhibited systems) and performance of KHIs at high water cut and/or high subcooling is not well understood. In this work, a high-pressure visual stirred tank reactor was employed to investigate the impact of THIs and KHIs on the kinetics of the complex hydrates of natural gas mixtures (CH4/C2H6/C3H8) and cyclopentane at high water-cut and high subcooling (∼21 °C). Various concentrations of a THI, mono-ethylene glycol (MEG) with a dosage ranging from 0.1 to 25 wt %, and multiple KHIs (polyvinylpyrrolidone (PVP k-30, PVP k-90), caprolactam, butyl glycol ether (BGE), and polyglycerin with 0.1 wt % dosage) were evaluated for hydrate formation kinetics, onset hydrate formation/nucleation temperature, and morphological changes. Gas uptake results reveal that hydrate blockage risk is higher at low MEG content (0.1 to 10 wt %) compared to the baseline, while a significant reduction in gas uptake was observed for the high MEG content trials (20–25 wt %). With 20 and 25 wt % MEG, the hydrate nucleation temperature was reduced by 10–12 °C compared to the baseline. In context to KHIs impact, 0.1 wt % BGE and caprolactam promoted the nucleation temperature and the rate of hydrate formation/gas uptake. However, PVPs not only reduced the gas uptake kinetics but also lessened the hydrate nucleation temperature by 6–8 °C compared to the baseline data. Our results may offer new insights into optimizing hydrate inhibitors dosage to diminish the risk of hydrate blockage in subsea pipelines.

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Investigating hydrate formation rate and the viscosity of hydrate slurries in water-dominant flow: Flowloop experiments and modelling

Cited by 26 publications

References 51 publications

Behavior of Methane Hydrate-in-Water Slurries from Shut-in to Flow Restart

Behavior of Methane Hydrate-in-Water Slurries from Shut-in to Flow Restart

Spatial Distribution and Phase Transition Characteristics of Methane Hydrate in the Water-Excess and Gas-Excess Deposits

Elucidating the Impact of Thermodynamic Hydrate Inhibitors and Kinetic Hydrate Inhibitors on a Complex System of Natural Gas Hydrates: Application in Flow Assurance

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