Novel approaches to waxy crude restart: Part 1: Thermal shrinkage of waxy crude oil and the impact for pipeline restart

Phillips, David A.; Forsdyke, Ivor N.; McCracken, Ian R.; Ravenscroft, P.

doi:10.1016/j.petrol.2010.11.009

Cited by 47 publications

(26 citation statements)

References 34 publications

(54 reference statements)

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“…During the pipeline restart process, the formed gel needs to be broken. [5][6][7] Therefore, an accurate rheological model is necessary to simulate pipeline shut-in and restart processes. [8] Various rheological models exist for fluid behavior prediction, several which are based on Herschel-Bulkley [9] or cross formulations.…”

Section: Strain-dependent Rheological Model and Pressure Wave Predictmentioning

confidence: 99%

Strain-Dependent Rheological Model and Pressure Wave Prediction for Shut in and Restart of Waxy Oil Pipelines

Zhao

Paso

Sariman

et al. 2014

Journal of Dispersion Science and Technology

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Waxy oil gelation and rheology is investigated and modeled using strain-dependent viscosity correlations. Rotational rheometry shows a sharp viscosity increase upon gel formation. High creeping flow viscosities are observed at small deformation conditions prior to yielding. A new strain-dependent rheological model, following analogous formulation to the Carreau-Yasuda shear rate-dependent model, captures viscosity reduction associated with yielding. In addition, shear viscosity and extensional viscosity are investigated using a capillary rheometry method. Distinct shear-thinning behavior is observed in the shear mode of deformation, while distinct tension-thinning behavior is observed in the extensional mode of deformation for the model fluid systems. High Trouton ratios are obtained for the gelled model fluid systems, confirming strongly non-Newtonian fluid rheology. Finally, axial pressure wave profiles are computed at real pipeline dimensions for idealized moderate yield stress fluids using a computationally efficient 1D pipeline simulator. The Rønningsen time-dependent gel degradation model is used to emulate the fluid rheology in the simulator. Axial stress localization phenomena are shown to depend on the overall magnitude of gel degradation as established by the reduction in yield value. A high degree of gel degradation serves to afford flow commencement in a timely manner.

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Section: Strain-dependent Rheological Model and Pressure Wave Predictmentioning

confidence: 99%

Strain-Dependent Rheological Model and Pressure Wave Prediction for Shut in and Restart of Waxy Oil Pipelines

Zhao

Paso

Sariman

et al. 2014

Journal of Dispersion Science and Technology

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“…The formation of voids in wax-oil gel was reported to make the waxy crude oil fluid compressible, which would make the restart pressure and pipeline design parameters lower than the estimated values from the conventional equation. As a result of thermal shrinkage of waxy crude oil during cooling, the formation of intra-gel voids is eminent [8][9][10]. Many research papers also recommended the understating of thermal shrinkage and the resulting gas voids formation to predict the restart pressure as accurately as possible [11].…”

Section: Introductionmentioning

confidence: 99%

Investigation of convective heat transfer coefficient and initial temperature of waxy crude oil on the formation of voids

Chala¹,

Sulaiman²,

Japper-Jaafar³

et al. 2016

Int. J. Automot. Mech. Eng.

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This paper presents the convective heat transfer coefficient of waxy crude oil while undergoing cooling and reports the influence of initial temperature on the intra-gel void formation. A flow loop rig was used to cool down waxy crude oil to the same end temperature while varying the initial temperature to observe the effects of initial temperature on the voids formed. The convective heat transfer coefficient and heat transfer rate of waxy crude oil subjected to cooling were calculated. It was observed that the heat transfer rate and the convective heat transfer coefficient of waxy crude oil below the wax appearance temperature were much lower than that of the Newtonian liquid crude oil owing to the wax crystal formation entrapping some liquid crude oil within it, below which the formation of voids is eminent. In addition, it was found that lower initial temperatures tend to form higher void volumes near pipe walls and in the entire pipe with a maximum change in void volume of 0.9% observed between the maximum and the minimum initial temperature tested. The insignificant influence of initial temperature on intra-gel void formation was also observed as the waxes are liquid above the wax appearance temperature.

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“…Despite very large reserves, their exploitation is limited by their high viscosity". Looking for best ways to overcome this limitation, several reviews, experimental and numerical works are available in scientific literature, as for example : Pouraria et al (2016), Hart et al (2014), Santos et al (2014), Aiyejina et al (2011), Palau et al (2011), Phillips et al (2011), Goldstein et al (2010, Li et al (2010), Ashrafizadeh and Kamran (2010), Guozhong and Gang (2010), Saniere et al (2004), among others, reflecting the interest of the scientific community and industry on this topic.…”

Section: Introductionmentioning

confidence: 99%

Influence of heat transfer on two-phase flow behavior in onshore oil pipelines

et al. 2016

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<p>Computational tools for simulation of multiphase flow in oil pipelines are of great importance for the determination of the technical feasibility of the production in oilfields. The present article presents the mathematical and numerical modeling of the oil biphasic flow in a partially submerged onshore pipeline. The biphasic behavior of the heavy oil of 13,2ºAPI is translated by the Dukler correlation. The oil’s viscosity is regarded as dependent on the temperature and on the API density of the oil by means of the Hossain correlation. The pipeline, of 3,600m and 4 inches (10.16cm) in diameter, transports the oil from a collecting station to a storage center and consists of three sections. The first and third sections are above ground and are in contact with the external environment. The intermediate section is sitting on the river bed and is the critical part of the pipeline, once high heat losses are observed. The influence on the type of pipe insulation in the pressure and temperature gradients was analyzed with the aid of commercial 1D software Pipesim®. The results, of this 1D and non-isothermal problem with prescribed outlet pressure, show that the use of isolation when appropriately designed in terms of material quality and thickness is of utmost importance to maintain the heat transfer at low levels, in order to ensure the movement of fluids in long sections without compromising the system operation.</p>

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Novel approaches to waxy crude restart: Part 1: Thermal shrinkage of waxy crude oil and the impact for pipeline restart

Cited by 47 publications

References 34 publications

Strain-Dependent Rheological Model and Pressure Wave Prediction for Shut in and Restart of Waxy Oil Pipelines

Strain-Dependent Rheological Model and Pressure Wave Prediction for Shut in and Restart of Waxy Oil Pipelines

Investigation of convective heat transfer coefficient and initial temperature of waxy crude oil on the formation of voids

Influence of heat transfer on two-phase flow behavior in onshore oil pipelines

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