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This paper reviews the mechanisms of initiation and the prevention of top-of-the-line corrosion (TLC). Recent research and developments are highlighted and validated to arrive at best practices for control of this significant corrosion manifestation. Water condensation and/or hydrate formation at the top of pipelines are serious design/operation considerations in pipelines. This paper reports the results of tests conducted in a new experimental setup constructed for investigating gas-hydrate risks in varied operational scenarios.
A computational fluid dynamics model is proposed to analyze the effect of hydrate flow in pipelines using multiphase-flow-modeling techniques. The results will identify the cause of pipeline failure, regions of maximum stress in the pipeline, and plastic deformation of the pipeline. The 9th International Conference on Gas Hydrates featured discussions on key advancements in flow assurance, including the concept of risk management and anti-agglomerates being applicable strategies in transient operations. A BP flow assurance manager explains a methodology for determining and mitigating flow assurance risks. A BP flow assurance engineer discusses the shift in hydrate management strategy from complete avoidance to risk mitigation for an offshore dry tree facility.
Penspen will also carry out engineering services on the Zirku Island plant. Wood is Shell’s exclusive partner for Shell’s Smart Choke technology, which suppresses riser-induced slugging. A small core team with the ability to make decisions was responsible for getting a subsea tie-back project up to sanction within a short-time frame. SPE’s technical sections offer communities rich with industry expertise. And your engagement adds to the wealth of knowledge to be shared.
Methane hydrate in the porous medium is formed within the pores of the sediments. The presence of a porous medium enhanced the heat transfer, whereas the presence of a hydrate promoter could enhance the mass transfer between the liquid-gas interface. In this study, we have studied the effect of sediment particle size and type of promoter on the kinetics of the methane hydrate formation and dissociation in the combined system. Environment-friendly amino acids (L-valine, L-methionine & L-histidine) and surfactant Sodium dodecyl sulfate are used as a promoter with four different particle sizes (46.4-245 μm, 160-630μm, 480-1800μm, 1400-5000μm) silica sand. Isothermal experiments are carried out using 3000 ppm promoter concentration at 100 bar, 274.15°C using the rocking cell to investigate the induction time, gas uptake, hydrate saturation. Temperature is further lowered to 266.15K to investigate the dissociation behavior of methane hydrate to study the self-preservation effect in the combined system.
The experimental results show that induction time in the combined system decreases as a sediment particle size decreases. Gas uptake remained unchanged in the combined system by changing the sediment particle size. We also report similar formation kinetics of hydrophobic amino acids (L-valine, L- methionine) and SDS at four particle sizes. At similar hydrate saturation, SDS has displayed weaker self- preservation effects compare to a hydrophilic amino acid in the porous medium.
Results in this study, support the conclusion available through other studies at lower concentration (500 ppm) of SDS and provide additional information about formation behavior at higher concentration (3000 ppm) of SDS. Results collected in this research could be beneficial in the selection of environmentally friendly chemicals for rapid methane hydrate formation in sediments to be used either in laboratory studies or for natural gas storage and transportation.
Sun, Baojiang (China University of Petroleum, East China) | Fu, Weiqi (China University of Petroleum, East China) | Wang, Zhiyuan (China University of Petroleum, East China) | Xu, Jianchun (China University of Petroleum, East China) | Chen, Litao (China University of Petroleum, East China) | Wang, Jintang (China University of Petroleum, East China) | Zhang, Jianbo (China University of Petroleum, East China)
Methane hydrate slurry in a water-continuous system is a significant production issue during pilot explorations for natural gas and natural gas hydrates in a deepwater environment. This work investigated the morphology and rheology of hydrate slurry with hydrate concentrations from 6 to 11% and shear rates from 20 to 700 s–1. Although hydrate slurry is widely considered a pseudoplastic fluid, in our experiment, hydrate slurry exhibited shear-thinning behavior in low-shear-rate conditions and shear-thickening behavior in high-shearrate conditions. The breakup of agglomerates built up between hydrate particles by shear force induced shear-thinning behavior in low-shear-rate conditions. The collision between monodispersed hydrate particles resulted in shear-thickening behavior in high-shear-rate conditions. The critical shear rate was proposed to describe the transition between the shear-thinning and shear-thickening behaviors of the hydrate slurry, which was a function of the hydrate concentration. Empirical Herschel-Bulkley-type equations were developed to describe the rheology of the hydrate slurry for both conditions.
May, Eric F. (University of Western Australia) | Metaxas, Peter J. (University of Western Australia) | Lim, Vincent W. S. (University of Western Australia) | Jeong, Kwanghee (University of Western Australia) | Norris, Bruce W. (University of Western Australia) | Kuteyi, Temiloluwa O. (University of Western Australia) | Stanwix, Paul L. (University of Western Australia) | Johns, Michael L. (University of Western Australia) | Aman, Zachary M. (University of Western Australia)
Quantitative prediction of gas hydrate formation risk is critical for the successful implementation of riskbased approaches to hydrate management in subsea production. Here we use a high pressure, stirred, automated lag-time apparatus and a high pressure acoustic levitator to experimentally obtain smooth probability distributions describing stochastic hydrate formation. Robust, repeatable hydrate nucleation and growth rate probability distributions as a function of induction time and subcooling are measured for various gases, shear rates and inhibitor dosages in systems with interfacial areas ranging from (0.1 to 60) cm 2 . The results reveal that new engineering models can be used to reliably predict hydrate formation probability. Importantly these new models have solid theoretical foundations which enables them to be generalized with confidence to industrial systems.