Study of asphaltene deposition in wellbores during turbulent flow

Paes, D. M.; Ribeiro, Paulo Leonardo Lima; Shirdel, Mahdy; Sepehrnoori, Kamy

doi:10.1016/j.petrol.2015.02.010

Cited by 27 publications

(13 citation statements)

References 17 publications

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“…In deposition models the main factors governing deposition rate are the number of destabilized particles, the size of destabilized particles (which governs their diffusivity and transport through the liquid), the flow conditions (hydrodynamics) and other environmental conditions (e.g. temperature) [57,58,59]. Generally, deposition (which involves asphaltene-asphaltene interaction) is not considered to be reaction-limited, even though there is evidence that in the early stages of aggregation and at low heptane vol % the rate of aggregation is reaction-limited [41,42].…”

Section: Discussionmentioning

confidence: 99%

Deposition of Asphaltene from Destabilized Dispersions in Heptane–Toluene

2018

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Deposition of carbonaceous materials, such as asphaltene, is a major problem in petroleum production. During production, changing environmental conditions destabilize asphaltene, resulting in dispersions that are out of equilibrium, where asphaltene is aggregating or flocculating. Key to developing the most effective strategies for tackling this problem, is a fundamental understanding of asphaltene deposition behaviour. A quartz crystal microbalance with dissipation monitoring (QCM-D) is used to study asphaltene deposition from non-equilibrium dispersions generated by in-line mixing of asphaltene in toluene (a solvent) with n-heptane (a precipitant). The effects of heptane:toluene ratio and destabilization time are investigated. At high heptane:toluene ratio the rate of asphaltene aggregation is faster and large flocs form by the time the flowing liquid reaches the QCM cell. In this case, the rate of deposition decreases with deposition time. At low heptane:toluene ratio the rate of asphaltene aggregation is slower, hence large flocs do not form before the flowing liquid reaches the QCM cell, and deposition of smaller aggregates occurs. Here the deposition rate is constant with time. The deposited mass is greatest before the formation of large flocs and at short destabilization times, where the particle distribution is furthest from equilibrium. Destabilized small particles existing immediately after a destabilization event pose a greater deposition problem than the flocs which subsequently form. This may be a contributing factor in the existence of deposition "hotspots" at certain locations in the production pipeline. Pushing destabilized dispersions to their new equilibrium distributions as quickly as possible may be a preventative strategy to combat deposition. The dissipation-frequency relationship monitored by QCM-D is sensitive to the nature of deposited asphaltene films and may be used as a diagnostic tool.

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Section: Discussionmentioning

confidence: 99%

Deposition of Asphaltene from Destabilized Dispersions in Heptane–Toluene

2018

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“…The concentration of asphaltene we use (0.1 gL⁻¹ in heptanetoluene) is much lower than that in the dead crude oil (60.7 gL⁻¹, density of crude oil at 20°C is 0.877 gcm⁻³ and asphaltene content is 5.32 wt%). The flow conditions are known to be important and in our case the flow is laminar (Re = 49 in the tubing before the QCM and Re = 2.7 inside the QCM), while in reality it would be turbulent (Re = 10⁴ -10⁶) (Paes et al, 2015). Additionally, the temperature and pressure are different.…”

Section: Inhibition Mechanism: Carbonaceous Materials Deposition Frommentioning

confidence: 91%

Mechanism of an asphaltene inhibitor in different depositing environments: Influence of colloid stability

Campen

Moorhouse

Wong

2020

Journal of Petroleum Science and Engineering

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Additives are used to reduce unwanted carbonaceous deposits of asphaltenes on surfaces during petroleum production from natural oil and gas reservoirs. The working mechanism of formulated additive packages can be multifaceted. Additives may be effective in the bulk fluid by preventing asphaltenes aggregation, as well as at the surface by preventing asphaltenes adhesion. In this paper, we investigate the numerous different mechanisms by which an asphaltene inhibitor can interfere with the formation of carbonaceous deposits using a combination of techniques including dynamic light scattering to determine particle size distribution, quartz crystal microbalance with dissipation monitoring to examine deposition behaviour and atomic force microscopy to probe deposit morphology. The tested inhibitor prevents deposition of asphaltenes in toluene, where asphaltenes exist as a stable colloidal dispersion of nanoaggregates, by forming barrier-type films that inhibit asphaltenes adhesion and displacing adsorbed thin films of asphaltenes. However, inhibitor performance in heptane-toluene, where asphaltenes are destabilised, depends on the degree of destabilisation. At low heptane volume fraction, inhibitor slows the rate of deposition and deposition rate decreases with increasing inhibitor concentration. However, at high heptane volume fraction, inhibitor can increase the deposition rate, particularly when used in high concentration. At high heptane volume fraction, inhibitor addition alters the morphology of the deposit from that consisting of large flocculent aggregates to that consisting of smaller, submicrometer aggregates. This is consistent with the finding that inhibitor acts as an anti-agglomerant and prevents the formation of large aggregates in the bulk liquid. This paper shows that the impact of inhibitor addition depends on the environmental conditions encountered and the degree of destabilisation of the asphaltenes. Where inhibitor addition alters the nature of depositing species from large flocculent aggregates to smaller submicrometer aggregates, an increase in deposition rate may be observed.

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“…We also emphasize here that the majority of the recently published asphaltene deposition models do not account for the effect of varying particle size distribution on the deposition process (e.g. Kurup et al, Tavakkoli et al, Paes et al) that, in our opinion, restricts applicability of those models to forecasting deposition under field conditions.…”

Section: Introduction: Description Of the Asphaltene Deposition Modelmentioning

confidence: 87%

Asphaltene deposition in a Taylor‐Couette device and a pipe: Theoretically achievable critical deposition regimes

et al. 2016

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In this paper, the effects of major asphaltene deposition model parameters, particle‐particle collision, and particle‐wall sticking efficiencies as well as asphaltene content in a hydrocarbon fluid on asphaltene deposition in both a Taylor‐Couette device and production tubing are numerically studied. The possibility of an increase in asphaltene deposition rate as a result of adding asphaltene inhibitors is investigated. The computations show that this critical effect is achievable in a Taylor‐Couette device operating in a batch regime only if the particle collision and the particle‐wall sticking efficiencies are more than an order of magnitude higher than those identified for asphaltenes present in hydrocarbon fluids. Calculations of deposition in the Taylor‐Couette device show also that an increase in the asphaltene content causes an increase in the rate of fluid depletion of particles able to deposit. The deposition calculations for a vertical pipe demonstrate that, due to continuous precipitation of primary particles along the tubing, a hydrocarbon fluid cannot be depleted of particles able to deposit; therefore the maximum deposit thickness always increases with an increase either in the major model parameters or the asphaltene content. Thus, the model parameter values indicating critical deposition regimes are different from those inherent to real hydrocarbon fluids; therefore, these regimes cannot be achieved in practical applications.

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Study of asphaltene deposition in wellbores during turbulent flow

Cited by 27 publications

References 17 publications

Deposition of Asphaltene from Destabilized Dispersions in Heptane–Toluene

Deposition of Asphaltene from Destabilized Dispersions in Heptane–Toluene

Mechanism of an asphaltene inhibitor in different depositing environments: Influence of colloid stability

Asphaltene deposition in a Taylor‐Couette device and a pipe: Theoretically achievable critical deposition regimes

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