Gas void formation in statically cooled waxy crude oil

Chala, Girma T.; Sulaiman, Shaharin Anwar; Japper-Jaafar, Azuraien; Abdullah, Wan Ahmad Kamil Wan; Mokhtar, Mior Maarof Mior

doi:10.1016/j.ijthermalsci.2014.06.034

Cited by 39 publications

(14 citation statements)

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“…All these efforts are taken to reduce wax deposition and mitigate in such a way that wax layer thickness can be predicted and addressed for maintenance once it reaches to a caution limit. Hence, predicting wax deposition can help in preventive maintenance and costeffectiveness [9][10][11][12][13]16].…”

Section: Introductionmentioning

confidence: 99%

Wax Deposition in Crude Oil Transport Lines and Wax Estimation Methods

Alnaimat¹,

Ziauddin²,

Mathew³

2020

Intelligent System and Computing

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Petroleum industry is one of the major industries serving the energy demands. Flow assurance is essential for providing continuous fuel supply. Wax deposition is the main issue that affects flow assurance or reduces the efficiency of transporting crude oil. As the maintenance cost of repairing and troubleshooting is very high, addressing issues related to flow assurance becomes critical in the petroleum industry. This chapter will explore methods used for reducing, cleaning, and monitoring deposition of wax. Wax dissolved in the crude oil gets crystallized causing accumulation across the pipe walls once the bulk temperature of the crude oil gets lower than wax appearance temperature (WAT). Mechanical, thermal, chemical, and microbial methods highlighting general practice in the industry are discussed in this chapter. Next, the direct techniques providing information about the numerical wax deposition models used along with scientific measurement techniques are emphasized. Later, the indirect measurement techniques are discussed providing information about the external probing and nondestructive techniques to obtain information about wax layer deposition inside the pipe. The role of artificial intelligence and use of fuzzy logic for effective wax prediction or in developing the existing wax numerical models are emphasized in the last section.

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Section: Introductionmentioning

confidence: 99%

Wax Deposition in Crude Oil Transport Lines and Wax Estimation Methods

Alnaimat¹,

Ziauddin²,

Mathew³

2020

Intelligent System and Computing

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“…*Formation and deposition of paraffin wax on the inner wall of production facilities and transportation pipelines continues to be a critical operational problem faced by the oil industry (Alcazar-Vara and Buenrostro-Gonzalez, 2013; Jafari Ansaroudi et al, 2013;Chala et al, 2014;Coto et al, 2014;Elhaddad et al, 2015;Zhang, 2014;Quan et al, 2015). Petroleum industries worldwide have been threatened by the risk of wax crystallisation and deposition which leads to tremendous economic losses due to the chemicals, well shut-in, choking of the flowlines, reduced production, less utilization of capacity, increased manpower attention and extra horse-power requirement.…”

Section: Introductionmentioning

confidence: 99%

Calculation of wax appearance temperature directly from hydrocarbon compositions of crude oil

Hosseinipour¹

2019

Int. j. adv. appl. sci.

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The purpose of this research is to develop a correlation in order to calculate the wax appearance temperature directly from hydrocarbon compositions of crude oil. Different methods have been used to measure wax appearance temperature including experimental instruments and thermodynamic models. A lot of empirical correlations have been used to calculate the physical properties of crude oil. However, there are no correlations for calculating the wax appearance temperature of the crude oils based on hydrocarbon compositions of crude oil. Calculation of the wax appearance temperature has become crucial in the study of wax crystallisation to prevent any congealing of the crude oil in production facilities and transportation pipelines. In this study, new correlations based on the hydrocarbon compositions of crude oil are developed to calculate the wax appearance temperature. The DataFit ® scientific software's multiple nonlinear regression analysis tools are used as a platform to develop a novel correlation to calculate the wax appearance temperature. Two correlations are developed. The accuracy and reliability of these correlations were verified experimentally and thermodynamically by different thermodynamic models. The R 2 and AAD% for these correlations (Eqs. 4 and 5) are 0.973, 0.999, 0.0170 and 0.00028 respectively. It can be concluded that the correlation equations are acting better than the thermodynamic wax model in predicting the wax appearance temperature of the crude oils. However, this correlation does not have the capability of thermodynamic wax models in prediction of the phase equilibriums at any temperatures and pressures and are subject to availability of the hydrocarbon composition range as indicated.

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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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Gas void formation in statically cooled waxy crude oil

Cited by 39 publications

References 14 publications

Wax Deposition in Crude Oil Transport Lines and Wax Estimation Methods

Wax Deposition in Crude Oil Transport Lines and Wax Estimation Methods

Calculation of wax appearance temperature directly from hydrocarbon compositions of crude oil

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

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