Experimental study of the formation and deposition of gas hydrates in non-emulsifying oil and condensate systems

Straume, Erlend Oddvin; Kakitani, Celina; Merino‐Garcia, Daniel; Morales, Rigoberto E. M.; Sum, Amadeu K.

doi:10.1016/j.ces.2016.07.046

Cited by 37 publications

(30 citation statements)

References 11 publications

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“…Although hydrate management can substantially reduce the CAPEX and OPEX, there is still a significant lack of fundamental understanding in the growth and agglomeration phenomena of hydrates in multiphase systems. Different experimental apparatus, e.g., flowloops, , batch reactors, − and rocking cells, , give different growth kinetic rates (i.e., amount of gas consumed over time) and plugging tendencies (i.e., pressure drop and volumetric flow rate oscillations) even when similar gases (often methane or synthetic natural gas) and oils are used. Therefore, the literature still presents a process of trial and error in understanding both phenomena (growth kinetics and agglomeration) for the use of different gases, oils, and additives in different conditions of water cut, mixture flow rate, and presence of salt.…”

Section: Introductionmentioning

confidence: 99%

A Multiscale Approach for Gas Hydrates Considering Structure, Agglomeration, and Transportability under Multiphase Flow Conditions: I. Phenomenological Model

Bassani

Melchuna

Cameirão

et al. 2019

Ind. Eng. Chem. Res.

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A new topological model on how gas hydrates form, grow, and agglomerate for oil and water continuous flow, with and without surfactant additives, is presented. A multiscale approach is used to explain how the porous structure of gas hydrates and the affinity between the phases affect the particle morphology and their agglomeration. We propose that gas consumption due to hydrate growth happens mostly in the water trapped inside the capillaries of the hydrate structure near the outer surface of the particles. This approach is herein referred to as the “sponge approach” and is treated as a surface problem, instead of the volume problem often treated in literature (the “shell approach”). Affinity between phases (which in a macro point of view is interpreted as a wetted angle that gives rise to capillarity forces and that can be changed by the use of surfactant additives) describes the preferential entrapment of oil or water inside the hydrate sponge structure. Yet by splitting agglomeration into smaller processes and depending on the morphology of the particles and on the evolution of the porous structure of the hydrates, (i) capillarity bridges may form, causing particles to be sticky, and (ii) water may be available at the outer surface of the particles and may promote consolidation of particle–particle (agglomeration) or particle-wall (deposition). The settling of slurries is treated as a separated solid–liquid flow instability problem once mixture deceleration (due to phase consumption during crystallization) and particle size (due to growth and agglomeration) are known. We also propose a new explanation on how surfactants act as anti-agglomerants in oil continuous flow, differently from the common DLVO theory used in literature, which can only explain anti-agglomeration of particles much smaller than the ones formed over droplets of a very fine dispersion flow.

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Section: Introductionmentioning

confidence: 99%

A Multiscale Approach for Gas Hydrates Considering Structure, Agglomeration, and Transportability under Multiphase Flow Conditions: I. Phenomenological Model

Bassani

Melchuna

Cameirão

et al. 2019

Ind. Eng. Chem. Res.

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“…The role of KHIs is to delay the nucleation or growth of hydrate crystallization while AAs allow the hydrate formation but help to disperse hydrate particles finely in production fluids, in other words, preventing hydrate agglomeration and plugs. Recently, AAs are widely used [3][4][5] due to their ability to avoid hydrate accumulation and plugging and their role as hydrate KHIs.…”

Section: Introductionmentioning

confidence: 99%

Relative Pressure Drop Model for Hydrate Formation and Transportability in Flowlines in High Water Cut Systems

et al. 2020

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Today, oil and gas fields gradually become mature with a high amount of water being produced (water cut (WC)), favoring conditions for gas hydrate formation up to the blockage of pipelines. The pressure drop is an important parameter which is closely related to the multiphase flow characteristics, risk of plugging and security of flowlines. This study developed a model based on flowloop experiments to predict the relative pressure drop in pipelines once hydrate is formed in high water cutsystems in the absence and presence of AA-LDHI and/or salt. In this model, the relative pressure drop during flow is a function of hydrate volume and hydrate agglomerate structure, represented by the volume fraction factor (Kv). This parameter is adjusted for each experiment between 1.00 and 2.74. The structure of the hydrate agglomerates can be predicted from the measured relative pressure drop as well as their impact on the flow, especially in case of a homogeneous suspension of hydrates in the flow.

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“…It is, however, not suitable to achieve proper dispersion of phases that simulates the multiphase flow conditions in flowlines . A rocking cell with a rolling ball is also widely used for laboratory studies because it can simply generate the flow by rocking. , Phases in the rocking cell are better dispersed, but the flow is still relatively stagnant, and the rolling ball actually causes more disturbances to the flow, resulting in a nonspecific flow regime and dispersion of the phases. Table lists the characteristics for each experimental system.…”

Section: Introductionmentioning

confidence: 99%

Rock-Flow Cell: An Innovative Benchtop Testing Tool for Flow Assurance Studies

Melchuna

Zhang

et al. 2019

Ind. Eng. Chem. Res.

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Flow assurance is a critical component in the design and operation of robust oil/gas production systems. Undesired precipitation of solids (gas hydrates, wax, asphaltenes, scale) reduces the production rate and often leads to costly and hazardous disruptions. Many experimental and modeling efforts have been made to build knowledge of managing such risks. However, a major difficulty is to transfer the laboratory data to the field conditions. We introduce a new experimental system, the rock-flow cell, which is compact and requires fewer resources to build and operate. This system can readily achieve different flow regimes by controlling the liquid loading, water cut, and rocking angle/speed. A sight glass visualizes when, where, how, and how much solid forms and precipitates out. Gas hydrate formation tests with anti-agglomerants are presented to demonstrate the capabilities. The rock-flow cell is an innovative testing tool for flow assurance studies by properly capturing thermohydraulic conditions in actual flowlines.

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Experimental study of the formation and deposition of gas hydrates in non-emulsifying oil and condensate systems

Cited by 37 publications

References 11 publications

A Multiscale Approach for Gas Hydrates Considering Structure, Agglomeration, and Transportability under Multiphase Flow Conditions: I. Phenomenological Model

A Multiscale Approach for Gas Hydrates Considering Structure, Agglomeration, and Transportability under Multiphase Flow Conditions: I. Phenomenological Model

Relative Pressure Drop Model for Hydrate Formation and Transportability in Flowlines in High Water Cut Systems

Rock-Flow Cell: An Innovative Benchtop Testing Tool for Flow Assurance Studies

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