Investigation of thickness and wax content of wax deposits in polyethylene pipe using a flow loop

AIChE Journal ◽  
2020 ◽  
Vol 67 (1) ◽  
Author(s):  
Rongbin Li ◽  
Qiyu Huang ◽  
Dongxu Zhang ◽  
Xiangrui Zhu ◽  
Jinxu Shan ◽  
...  
Keyword(s):  
Flow Loop ◽  
Polyethylene Pipe ◽  
Wax Content ◽  
Wax Deposits

Investigation of delayed formation of wax deposits in polyethylene pipe using a flow-loop

2021 ◽  
Vol 196 ◽  
pp. 108104
Author(s):  
Rongbin Li ◽  
Qiyu Huang ◽  
Xiangrui Zhu ◽  
Dongxu Zhang ◽  
Yang Lv ◽  
...  
Keyword(s):  
Flow Loop ◽  
Polyethylene Pipe ◽  
Wax Deposits

Experimental Investigation of the Difference in Wax Deposition Aging Rate Between Polyethylene and Steel Pipes

2020 ◽  
Author(s):  
Rongbin Li ◽  
Yaping Li ◽  
Danfu Cao ◽  
Junfang Wang ◽  
Xin Liu
Keyword(s):  
Operating Conditions ◽  
Wax Deposition ◽  
Flow Loop ◽  
Waxy Crude Oil ◽  
Scanning Calorimetry ◽  
Aging Rate ◽  
Wax Content ◽  
The Difference ◽  
Dsc Method ◽  
Wax Deposits

Abstract Wax deposition is an intrinsic problem existing in the production and transportation of waxy crude oil. In the oilfield, non-metallic pipe especially high-density polyethylene pipe (HDPE) has been widely used to solve corrosion problems due to its excellent performance in intensity and corrosion. However, the wax deposition problem in polyethylene (PE) pipe has never been evaluated using dynamic and systemic apparatus. Only a few studies focus on the wax deposition on the coated polyethylene surface by using the cold finger apparatus in recent decades. In this study, the wax deposition experiments were performed using an in-door flow-loop with detachable PE and stainless steel (SS) test sections under the laminar flow regime at the same time to investigate the difference in wax deposition aging rate between the PE and SS pipes. The wax deposits under different operating conditions in both PE and SS pipes were sampled by three layers to study the aging rate at different radial locations during the wax deposition. The wax precipitation characteristics of the wax deposits were determined by using the differential scanning calorimetry (DSC) method. It was found that the wax contents of the wax deposits in PE pipe were lower than that in the SS pipe. And the difference of the wax content between PE pipe and SS pipe decreases with the depositing duration. Eventually, the wax contents of the wax deposits in PE pipe were almost the same as that in the SS pipe. The heat conduction and heat transfer processes in PE pipe and SS pipe were analyzed. The thermal gradient and the concentration gradient at wall were calculated and combined with the heat and mass transfer of wax during the wax deposition to illustrate the difference in wax content. It was found that the variations of the thermal and concentration gradients have significant effects on the diffusion process of wax molecules within the wax deposit layer and thus changing the aging rate. The comparisons and findings of wax deposition between the two kinds of pipes have provided a significant reference for the application of non-metallic pipe in the oilfield.

Experimental Study on Wax Removal With Real Wax Deposits

2018 ◽  
Author(s):  
Weidong Li ◽  
Qiyu Huang ◽  
Xue Dong ◽  
Xuedong Gao ◽  
Lei Hou
Keyword(s):  
Test Section ◽  
Wax Deposition ◽  
Flow Loop ◽  
Gravity Settling ◽  
Experimental Apparatus ◽  
Field Practice ◽  
Force Profile ◽  
Wax Content ◽  
Wax Deposits ◽  
Wax Removal

Pipeline pigging is one of the most widely used wax remediation techniques in field practice. However, it still depends heavily on “rule-of-thumb” due to the limited understanding of wax deposit properties and wax removal mechanisms. By far, laboratory studies on pipeline pigging generally suffer a gross defect in test materials, i.e., the big discrepancy between the experimental wax samples and real wax deposits. To this end, this paper aims to explore the wax removal in pigging with naturally deposited wax, using a self-designed experimental facility. Wax deposit mass and wax content, two decisive indexes affecting wax removal, were also investigated. The experimental apparatus consists of two parts: a flow loop equipped with a detachable test section to achieve real wax deposits and a wax removal apparatus to perform pigging operations. The test section can be conveniently detached from the flow loop and/or mounted onto the wax removal apparatus for a quick conversion between wax deposition and pigging operation. The results indicate that a higher bulk flow temperature decreases the wax deposit mass and increases the wax content of deposit. Additionally, the distributions of wax content and wax layer thickness suggest that gravity settling plays no role in wax deposition. Moreover, the wax resistive force profile of naturally deposited wax presents four distinct stages, i.e., the build-up phase, the pre-plug phase, the plug phase and the production phase. To the best of the authors’ knowledge, this is the first study on wax removal with real wax deposits. It paves the way for the application of previous artificial-wax-based researches to real wax deposit scenarios.

Influence of Hydrostatic Pressure on the Formation of Voids in Gelled Crude Oil

2021 ◽  
Author(s):  
Girma T. Chala ◽  
Shaharin A. Sulaiman ◽  
Azuraien Japper-Jaafar ◽  
Wan Ahmad Kamil Wan Abdullah
Keyword(s):  
Hydrostatic Pressure ◽  
Crude Oil ◽  
Vertical Pipe ◽  
Flow Loop ◽  
Waxy Crude Oil ◽  
Horizontal Pipe ◽  
Waxy Crude ◽  
Oil Transportation ◽  
Wax Content ◽  
Lower Temperature

Production of waxy crude oil from offshore fields has increased in the last decade. However, the operation is being challenged with the high wax content of crude oil that tends to precipitate at lower temperature. This paper presents the effects of hydrostatic pressure on the voids formed in waxy crude oil gel. A flow loop rig that simulates offshore waxy crude oil transportation was used to produce the gel. A Magnetic Resonance Imaging of 3-Tesla system was used to scan the gelled samples in horizontal and vertical pipes. The hydrostatic pressure effect was found to be most significant near the pipe wall as a change in percent voids volume of 0.53% was observed at that region. In particular, the voids volume reduction was more pronounced in the lower half side of the pipe. The total volume of voids in the vertical pipe was lower than that in the horizontal pipe, and this suggests that the gel in the vertical pipe became denser due to the effects from the hydrostatic pressure. Conversely, the voids volume around the pipe core in the vertical pipe was higher when compared to that in the horizontal pipe. The change in voids volume near the pipe core and wall shrunk to a minimum and converged to 0.18% voids volume at larger duration of the hydrostatic effect. Further, hydrostatic pressure was observed to have significant influences for higher duration making the void size to be distributed across and along the pipeline; however, it was found to have insignificant effects on voids size distribution for smaller duration. The findings of this study can help for better understanding of voids formation in vertical pipelines that would further assist in developing a model predicting restart pressure accurately.

Experimental Investigation of Wax Deposition at Different Deposit Locations Through a Detachable Flow Loop Apparatus

2014 ◽  
Author(s):  
Si Li ◽  
Qiyu Huang ◽  
Wenda Wang ◽  
Changhui Wang ◽  
Zhenjun Ding
Keyword(s):  
Temperature Interval ◽  
Flow Rate ◽  
Test Section ◽  
Measurement Techniques ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Wax Deposition ◽  
Flow Loop ◽  
Deposit Thickness ◽  
Wax Content

Wax deposition has always been a focus in the research field of flow assurance. Operating conditions are among the predominant factors that control the deposition rate and the nature of the formed deposits. However, the disadvantages of the available wax thickness measurement techniques applied to laboratory flow loops limit deeper studies on this issue. In this work, the effects of operating conditions, including temperature interval and flow rate, on wax deposition at different deposit locations are experimentally studied using a detachable flow loop apparatus. With the detachable test section, it is achievable to obtain the thickness and the wax content profiles of the deposit as functions of axial location and time. The temperature fields in the test section under both temperature intervals are simulated with CFD software FLUENT to provide more information for the analysis of deposition process. As the results manifest, the low temperature interval tends to intensify deposition, relating to the inner temperature field and wax precipitated property of the oil. The larger flow rate leads to a growth in the deposit thickness under the laminar flow regime and brings about a distinct rise in the wax content of deposit at inlet. In addition, the increase in deposit thickness and wax content indicates the phenomenon of deposit aging, and the wax deposit layer is thinner but with higher wax content at the inlet, due to the strong flow scour.

scholarly journals Review of the Factors that Influence the Condition of Wax Deposition in Subsea Pipelines

2018 ◽  
Vol 3 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Koh Junyi ◽  
Nurul Hasan
Keyword(s):  
Crude Oil ◽  
Residence Time ◽  
Flow Rate ◽  
Temperature Difference ◽  
Wax Deposition ◽  
Flow Loop ◽  
New Models ◽  
Wax Content ◽  
The Difference ◽  
Deep Depth

When crude oil is transported via sub-sea pipeline, the temperature of the pipeline decreases at a deep depth which causes a difference in temperature with the crude oil inside. This causes the crude oil to dissipate its heat to the surrounding until thermal equilibrium is achieved. This is also known as the cloud point where wax begins to precipitate and solidifies at the walls of the pipeline which obstruct the flow of fluid. The main objective of this review is to quantify the factors that influence wax deposition such as temperature difference between the wall of the pipeline and the fluid flowing within, the flow rate of the fluid in the pipeline and residence time of the fluid in the pipeline. It is found the main factor that causes wax deposition in the pipeline is the difference in temperature between the petroleum pipeline and the fluid flowing within. Most Literature deduces that decreasing temperature difference results in lower wax content deposited on the wall of the pipeline. The wax content increases with rising flow rate. As for the residence time, the amount of deposited wax initially increases when residence time increases until it reaches a peak value and gradually decreases. Flow-loop system and cold finger apparatus were used in literature investigations to determine the trends above. Three new models are generated through a regression analysis based on the results from other authors. These new models form a relationship between temperature difference, flow rate, residence time and Reynolds number with wax deposition. These models have high values of R-square and adjusted R-square which demonstrate the reliability of these models.

scholarly journals Development of an Approach for Determining the Effectiveness of Inhibition of Paraffin Deposition on the Wax Flow Loop Laboratory Installation

Inventions ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 3
Author(s):  
Pavel Ilushin ◽  
Kirill Vyatkin ◽  
Anton Kozlov
Keyword(s):  
Field Data ◽  
Correct Selection ◽  
Laboratory Studies ◽  
Flow Loop ◽  
Cold Finger ◽  
Average Deviation ◽  
Laboratory Installation ◽  
Perm Krai ◽  
Wax Deposits ◽  
Selection Of

The formation of wax deposits is a common phenomenon in the production and transportation of formation fluids. On the territory of the Perm Krai, this problem occurs in half of the mining funds. One of the most common and promising methods of dealing with these deposits is the use of inhibitor regents. The most popular technique for assessing the effectiveness of a wax inhibitor is the «Cold Finger», which has a number of significant drawbacks. This work presents a number of methods for assessing the effectiveness of inhibition of paraffin formation on the laboratory installation «WaxFlowLoop». A number of laboratory studies have been carried out to determine the effectiveness of a paraffin deposition inhibitor for inhibiting the paraffin formation process of four target fluids. Verification of the obtained values was carried out by comparing them with the field data. As a result of laboratory studies, it was found that the value of the inhibitor efficiency, determined by the «Cold Finger» method, differs from the field data by an average of 2 times. At the same time, the average deviation of the results determined at the «WaxFlowLoop» installation from the field data is 8.1%. The correct selection of a paraffin deposition inhibitor and its dosage can significantly increase the inter-treatment period of the well, thereby reducing its maintenance costs and increasing the efficiency of well operation.

An aging theory‐based mathematic model for estimating the wax content of wax deposits using the Fick's second law

AIChE Journal ◽  
2019 ◽  
Vol 66 (4) ◽  
Author(s):  
Rongbin Li ◽  
Qiyu Huang ◽  
Dongxu Zhang ◽  
Xiangrui Zhu ◽  
Jinxu Shan ◽  
...  
Keyword(s):  
Mathematic Model ◽  
Second Law ◽  
Aging Theory ◽  
Wax Content ◽  
Wax Deposits

A Comprehensive Investigation into the Effect of a Low Surface Energy Treatment on Gas Hydrate, Asphaltene, and Wax Formation, Deposition, and Adhesion

SPE Journal ◽  
2021 ◽  
pp. 1-12
Author(s):  
M. A. Pickarts ◽  
E. Brown ◽  
J. G. Delgado-Linares ◽  
V. Veedu ◽  
C. A. Koh
Keyword(s):  
Contact Angle ◽  
Surface Treatment ◽  
Gas Hydrate ◽  
Adhesion Force ◽  
Surface Treatments ◽  
Chemical Additives ◽  
Flow Loop ◽  
Complete Wetting ◽  
Static Contact ◽  
Wax Deposits

Summary The formation/precipitation and deposition of pipeline solids, such as gas hydrates, asphaltenes, and waxes have long plagued production fields. Given the vast differences in chemistries of these solids, any current prevention or mitigation strategy, particularly for cases in which multiple issues are a concern, is likely to involve an extensive assortment of chemical additives that are both costly and add complexity to the system. Surface treatments (coatings), on the other hand, present a relatively viable option for management strategies. A chemically and physically robust surface treatment with the ability to address deposition issues for multiple pipeline solids could not only decrease the operating expenditures for a field through material cost savings and obviation of downstream separation, but could also simplify produced fluids by eliminating additional chemicals from the mixture. The purpose of this study was to explore the feasibility of a particular surface treatment as part of a solids management strategy. This work used an omniphobic surface treatment to probe its effects on gas hydrate, asphaltene, and wax deposition. Specifically, an interfacial tensiometer (IFT) collected contact angle measurements for wettability studies. High-pressure rocking cells studied gas hydrate nucleation and deposition. A bench-scale flow loop quantified the deposition of oil and asphaltenes after a set time period. Finally, a mechanical shear device measured the adhesion force of wax deposits on untreated/treated surfaces. Static contact angle results showed that the omniphobic surface treatment had reduced surface interaction with water droplets in air, altering from the complete wetting on corroded surfaces to slightly hydrophobic conditions of greater than 100°. In addition, rocking-cell tests indicated that these omniphobic surface treatments may prevent gas hydrate deposition for up to 72 hours. The gas hydrate rocking-cell tests also demonstrated possible increases in induction time and occasional elimination of hydrate nucleation with the surface treatment. Finally, the surface treatment application, which also decreased surface roughness, showed that crude oil and asphaltene particles deposition, as well as the shear required to remove solidified wax deposits, could be reduced by a large factor. Overall, promising results were recorded for all major flow-assurance solids in the presence of the surface treatment.

Quality caracterisation of propolis tinctures by pharmacopoeial parameters and wax content

Planta Medica ◽  
2006 ◽  
Vol 72 (11) ◽  
Author(s):  
J Cvek ◽  
S Zubčic ◽  
D Vitali ◽  
I Vedrina-Dragojevic ◽  
S Tomic ◽  
...  
Keyword(s):  
Wax Content
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