Evaluation of Wax Deposition and Its Control During Production of Alaska North Slope Oils

Zhu, Tao; Walker, Jack A.; Liang, Jenn‐Tai

doi:10.2172/963363

Cited by 12 publications

(4 citation statements)

References 30 publications

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“…This may have contributed to its high wax content. This is in agreement with previous researcher findings (Zhu, Walker, & Liang, 2008). The asphaltene content of sample C was the highest while sample B contained the lowest percentage of asphaltene out of the four samples tested (Table 2).…”

Section: Fatty Acids Compositions Of the Seed Oilsupporting

confidence: 93%

A study on the use of plant seed oils, triethanolamine and xylene as flow improvers of Nigerian waxy crude oil

Akinyemi

Udonne

Efeovbokhan

et al. 2016

Journal of Applied Research and Technology

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Chemical methods are the most convenient and economical for wax precipitation and deposition prevention. The chemical additives so far in use have varied limitations, ranging from high cost to limited spread of crude oil that a particular additive can handle. The influence of cheaper natural chemicals, obtained from plant seeds (jatropha -JSO, rubber -RSO and castor -CSO) on the rheological properties and wax deposition tendencies of Nigerian waxy crude oil were investigated. Previously tested synthetic chemical additives (triethanolamine -TEA and xylene) were simultaneously examined too on the crude oils for comparative study. Four different crude oil samples obtained from Niger Delta region of Nigeria used for the study were characterized to obtain their hydrocarbon composition, wax content, pour points, viscosities, specific gravity and APIg using standard methods. The rheological properties such as apparent viscosity, plastic viscosity, yield stress were determined for the crude oils doped and undoped with the chemical additives using Fann V-G Standard Viscometer. The results obtained revealed that oils from the three seeds could be used as flow improvers and pour depressants for Nigerian waxy crude oil. Jatropha and castor seed oils depressed the pour point than the previously investigated triethanolamine. They are capable of depressing the pour point up to about 17 • C, and they can also reduce the viscosity of the waxy crude oil appreciably within 0.1-0.3% (v/v) dosage concentration. Also, CSO could exhibit as high as 77.7% paraffin inhibition efficiency (PIE) and JSO 73.5% at low concentration of doping.

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Section: Fatty Acids Compositions Of the Seed Oilsupporting

confidence: 93%

A study on the use of plant seed oils, triethanolamine and xylene as flow improvers of Nigerian waxy crude oil

Akinyemi

Udonne

Efeovbokhan

et al. 2016

Journal of Applied Research and Technology

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“…Unlike, in a laminar flow regime, where the thickness is relatively higher, δ wax ≈ 0.36mm at 5 l/min and δ wax ≈ 0.132mm at 7 l/min respectively. This is because in a laminar flow regime the shear effect and Brownian dispersion are insignificant (Zhu et al, 2008). Thus, the particles are well ordered and could easily deposited on the surface.…”

Section: Effect Of Blend a Inhibitor On The Wax Thickness And Depositmentioning

confidence: 99%

Depositional Behaviour of Highly Macro-Crystalline Waxy Crude Oil Blended with Polymer Inhibitors in a Pipe with a 45-Degree Bend

Makwashi

Barros

Sarkodie

et al. 2019

SPE Offshore Europe Conference and Exhibition

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Production, transportation and storage of highly waxy crude oil is very challenging. This is because they are usually characterised by high content of macro-crystalline waxes, predominantly consisting of n-alkanes (C 18 to C 36) that which could cause costly deposition within the wellbore and production equipment. The accumulation of deposited wax can decrease oil production rates, cause equipment breakdown, and clog the transport and storage facilities. Currently, different polymeric inhibitors have been utilised in the oil and gas field to mitigate and prevent wax deposition. However, as of today, there is no distinctive wax inhibitor that could work effectively for all oil fields. One of the objectives of this work is to study the efficacy of a blended commercial wax inhibitor-pour point depressant on wax deposition mitigation in a flow rig designed with 0 and 45-degree bends in the pipeline. Standard laboratory techniques using high-temperature gas chromatography (HTGC), rheometer rig, polarized microscope and elution chromatography were employed to obtain n-paraffin distribution, oil viscosity, WAT, pour point and SARA fractions. Series of experimentation were carried out with and without the inhibitor in a straight pipe test section. The severity of wax deposition in the pipeline built-in with a 45-degree bend is compared with a straight pipe. The blended inhibitor was tested at concentrations of 500, 1000, and 1500-ppm, under laminar and turbulent conditions. The crude oil sample was found to be naturally waxy with wax content of 19.75wt%, n-paraffin distributions ranges from C 15-C 74 , WAT and pour point of 30°C and 25°C respectively. The severity of wax deposition in the test section is 43% higher in 45-degree bend compared to straight pipe. However, the severity of the deposition was reduced to 12.3% at extremely low temperature and flow rate. Nonetheless, better inhibition performance was achieved at 25 and 30°C. The wax thickness was reduced from δ wax ≈ 0.36mm at 5 l/min to δ wax ≈ 0.132mm at 7 l/min at constant coolant temperature (25°C) and 1500-ppm, whereas, no wax deposition was observed at 11 l/ min. Mechanisms such as molecular diffusion due to frictional pressure losses, shear dispersion and gravity settling due to momentum change and hydrostatic, alongside with thermal difference are the main drivers for wax deposition in both straight and bend pipe. Whereas, the interaction mechanisms such as the nucleation, alongside with adsorption, co-crystallization, and solubilisation between the new blended inhibitor and the wax crystals provide an improved inhibition performance in the system even at extreme cases.

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“…Wax causes artificial blockage in flow path, leading to a reduction or interruption in production. In extreme cases, this can cause a pipeline or production facilities to be abandoned (Tao, et al, 2008). Downhole, wax deposition also leads to formation damage near the wellbore, reduction in permeability, changes in the reservoir fluid composition and fluid rheology due to phase separation as w ax solids precipitates (Sandyga, et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

The effect of polyethylene butene (PEB) and xylene on the shear stress of Niger delta crude oil

Odutola¹,

Allen²

2023

Global J. Eng. Technol. Adv.

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Crude oil production and transportation is plagued by several flow assurance issues especially in offshore environment with prevailing low temperature. One of the flow assurance challenges is the deposition of paraffin wax which usually changes the crude oil flow from Newtonian fluid flow to non- Newtonian fluid flow with increased viscosity. This increased viscosity can impede flow causing the installation of high horsepower pumps for fluid flow. In severe cases, paraffin wax has plugged the pipes and caused production disruption. It is therefore imperative to manage paraffin disposition in crude samples containing paraffin compounds (C18+). This research discusses the use of varying concentrations of Polyethylene Butene (PEB) in managing wax precipitation at various temperatures (10 °C to 35 °C) at a constant shear rate of 511(s-1). The reduction in crude oil temperature increased the shear stress in all experiments conducted. It was discovered that the increasing concentration of PEB from 500ppm to 5000ppm had a sinusoidal effect on reducing the shear stress. 500ppm of PEB effected a 19% reduction in shear stress, while 5000ppm effected a 35% reduction in shear stress. It is important for the engineer to make the choice of inhibitor concentration based on the degree of shear stress reduction required to optimize inhibitor usage.

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Evaluation of Wax Deposition and Its Control During Production of Alaska North Slope Oils

Cited by 12 publications

References 30 publications

A study on the use of plant seed oils, triethanolamine and xylene as flow improvers of Nigerian waxy crude oil

A study on the use of plant seed oils, triethanolamine and xylene as flow improvers of Nigerian waxy crude oil

Depositional Behaviour of Highly Macro-Crystalline Waxy Crude Oil Blended with Polymer Inhibitors in a Pipe with a 45-Degree Bend

The effect of polyethylene butene (PEB) and xylene on the shear stress of Niger delta crude oil

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