Study of the causes for wax deposition under the operating conditions of main oil pipelines

2020 ◽  
Vol 10 (6) ◽  
pp. 610-619
Author(s):  
Rustam Z. Sunagatullin ◽  
◽  
Rinat M. Karimov ◽  
Radmir R. Tashbulatov ◽  
Boris N. Mastobaev ◽  
...  
Keyword(s):  
Phase Diagrams ◽  
Total Content ◽  
Operating Conditions ◽  
Wax Deposition ◽  
Oil Saturation ◽  
Oil Pipelines ◽  
Thermobaric Conditions ◽  
Wall Zone ◽  
Significant Factors ◽  
Commercial Oil

The results of investigations of the main causes and the most significant factors of intensification of paraffin deposition in main oil pipelines are presented. A comprehensive analysis of the composition and properties of commercial oils and their sediments was carried out, according to which phase diagrams of equilibrium of oil dispersed systems were obtained using the example of commercial oils from Bashkir fields. Based on the phase diagrams, a curve of wax oil saturation was constructed, the analysis of which confirms that the existing thermobaric conditions during the operation of main oil pipelines do not allow transporting oil without the risk of waxing. It was noted a special influence of the value of the temperature gradient in the near-wall zone and the imbalance of the ratio of high-molecular oil components in commercial batches formed in the process of joint pumping on the intensity of waxing of sections of oil pipelines complicated by deposits, which was confirmed by statistical data on the frequency of pigging. The regularities obtained in this way are proposed to be used as an express method for predicting complications associated with intensive waxing of main oil pipelines. In order to quickly assess the risks of waxing of sections of main oil pipelines, an indicator is introduced that characterizes the ratio of the content of solid paraffins to the total content of resins and asphaltenes of oil, called the criterion of instability of a commercial oil batch.

A NEW WELDING MATERIAL FOR REGENERATION IN THE WELDING TECHNOLOGY BASED ON NICKEL. ANALYSIS OF THE COMPOSITION AND PROPERTIES OF DEFORMABLE HEAT-RESISTANT HIGH-CHROMIUM NICKEL-BASED ALLOYS FOR WELDED PARTS. ANALYSIS OF EXISTING FUELLING STATIONS TYPES AND VEHICLES USING HYDROGEN, HYDROGEN PRODUCTION AND STORING METHODS

2019 ◽  
pp. 43-48
Author(s):  
Ben Nengjun ◽  
Zhou Pengfei ◽  
Oleksandr Labartkava ◽  
Mykhailo Samokhin
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Nickel Alloys ◽  
Total Content ◽  
Operating Conditions ◽  
High Temperature Strength ◽  
High Chromium ◽  
Salt Corrosion ◽  
Tcp Phases ◽  
The Impact

This work involves an analysis of high-chromium high-temperature deformable wieldable nickel alloys for use in GTE repair assemblies. It is shown that the alloys EP868 (VZh98) and Haynes 230 can be used in welded assemblies with an operating temperature of 800-1100 °C. The alloys Nimonic 81, Nimonic 91, IN 935, IN 939, and Nicrotan 2100 GT also have a high potential for use in welded assemblies. They are characterized by a combination of good weldability, high-temperature strength, and resistance to scaling. There have been conducted studies on high-temperature salt corrosion of model nickel alloys. They allowed establishing the patterns of the impact of base metal alloying with chromium, aluminum, titanium, cobalt, tungsten, molybdenum, niobium, tantalum and rare earth metals on the critical temperature of the start of salt corrosion Tcor and the alloy mass loss. It has been established that alloys with a moderate concentration (13-16%) of chromium can possess satisfactory hightemperature corrosion resistance (HTC resistance) under the operating conditions of ship GTE. The HTC resistance of CrAl-Ti alloys improves upon reaching the ratio Ti/Al ˃ 1. Meanwhile, the ratio Ti/Al ˂ 1 promotes the formation of corrosion products with low protective properties. The positive effect of tantalum on the HTC resistance of alloys is manifested at higher test temperatures than that of titanium, and the total content of molybdenum and tungsten in alloys is limited by the condition 8Mo2 – 2W2 = 89. The presence of refractory elements stabilizes the strengthening phase and prevents formation of the ɳ-phase. However, their excess promotes formation of the embrittling topologically close packed (TCP) phases and boundary carbides of an unfavorable morphology. Based on the studies of the HTC resistance, there has been identified a class of model high-temperature corrosionresistant nickel alloys with a moderate or high chromium content (30%), Ti/Al ˃ 1, and a balanced content of refractory and rare-earth elements.

scholarly journals Role of Shearing Dispersion and Stripping in Wax Deposition in Crude Oil Pipelines

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4325
Author(s):  
Zhihua Wang ◽  
Yunfei Xu ◽  
Yi Zhao ◽  
Zhimin Li ◽  
Yang Liu ◽  
...  
Keyword(s):  
Crude Oil ◽  
Flow Rate ◽  
Critical Flow ◽  
Wax Deposition ◽  
Dominant Effect ◽  
Critical Flow Rate ◽  
Oil Pipelines ◽  
Oil Flow ◽  
Shearing Mechanism

Wax deposition during crude oil transmission can cause a series of negative effects and lead to problems associated with pipeline safety. A considerable number of previous works have investigated the wax deposition mechanism, inhibition technology, and remediation methods. However, studies on the shearing mechanism of wax deposition have focused largely on the characterization of this phenomena. The role of the shearing mechanism on wax deposition has not been completely clarified. This mechanism can be divided into the shearing dispersion effect caused by radial migration of wax particles and the shearing stripping effect caused by hydrodynamic scouring. From the perspective of energy analysis, a novel wax deposition model was proposed that considered the flow parameters of waxy crude oil in pipelines instead of its rheological parameters. Considering the two effects of shearing dispersion and shearing stripping coexist, with either one of them being the dominant mechanism, a shearing dispersion flux model and a shearing stripping model were established. Furthermore, a quantitative method to distinguish between the roles of shearing dispersion and shearing stripping in wax deposition was developed. The results indicated that the shearing mechanism can contribute an average of approximately 10% and a maximum of nearly 30% to the wax deposition process. With an increase in the oil flow rate, the effect of the shearing mechanism on wax deposition is enhanced, and its contribution was demonstrated to be negative; shear stripping was observed to be the dominant mechanism. A critical flow rate was observed when the dominant effect changes. When the oil flow rate is lower than the critical flow rate, the shearing dispersion effect is the dominant effect; its contribution rate increases with an increase in the oil flow temperature. When the oil flow rate is higher than the critical flow rate, the shearing stripping effect is the dominant effect; its contribution rate increases with an increase in the oil flow temperature. This understanding can be used to design operational parameters of the actual crude oil pipelines and address the potential flow assurance problems. The results of this study are of great significance for understanding the wax deposition theory of crude oil and accelerating the development of petroleum industry pipelines.

scholarly journals The Use of Biobased Surfactant Obtained by Enzymatic Syntheses for Wax Deposition Inhibition and Drag Reduction in Crude Oil Pipelines

Catalysts ◽  
2016 ◽  
Vol 6 (5) ◽  
pp. 61 ◽  
Author(s):  
Zhihua Wang ◽  
Xueying Yu ◽  
Jiaxu Li ◽  
Jigang Wang ◽  
Lei Zhang
Keyword(s):  
Drag Reduction ◽  
Crude Oil ◽  
Wax Deposition ◽  
Biobased Surfactant ◽  
Oil Pipelines

Polymeric Surfaces for Heavy Oil Pipelines To Inhibit Wax Deposition:  PP, EVA28, and HDPE

2006 ◽  
Vol 20 (2) ◽  
pp. 620-624 ◽  
Author(s):  
Cristina M. Quintella ◽  
Ana Paula S. Musse ◽  
Martha T. P. O. Castro ◽  
J. C. Scaiano ◽  
Larisa Mikelsons ◽  
...  
Keyword(s):  
Heavy Oil ◽  
Wax Deposition ◽  
Polymeric Surfaces ◽  
Oil Pipelines

Identifying Optimal Pigging Frequency for Oil Pipelines Subject to Non-Uniform Wax Deposition Distribution

2014 ◽  
Author(s):  
Wenda Wang ◽  
Qiyu Huang ◽  
Si Li ◽  
Changhui Wang ◽  
Xi Wang
Keyword(s):  
Pressure Drop ◽  
Model Prediction ◽  
Extreme Case ◽  
Wax Deposition ◽  
Deposition Model ◽  
Oil Pipelines ◽  
Pump Stations ◽  
The Cost

Wax deposition in oil pipelines causes reduced throughput and other associated problems. Periodical pigging program can effectively minimize the cost of wax deposition. This paper shows a typical pigging case study for a field pipeline subject to non-uniform wax deposition distribution by using a developed wax deposition model. The model prediction results prove that the wax is distributed in a short, localized accumulation along the first half pipeline. The resultant pressure drop along the pipeline was examined to reveal the effects of non-uniform wax deposition distribution on the pipeline production. In extreme case, the pressure drop of severe localized section increases by 50%, while this value between pump stations is merely 3%. A maximum wax thickness of 2–4 mm is used as a criterion to determine an optimal pigging frequency. The case study pipeline is recommended to be pigged at a frequency of 10 to 15 days, using by-pass pigs.

New Environmentally Friendly Solutions to Prevent Oil Pipelines Disasters

2015 ◽  
Vol 797 ◽  
pp. 334-344
Author(s):  
Michał Bardadyn ◽  
Marcelo Paredes ◽  
Mateusz Wrobel ◽  
Krystian Paradowski ◽  
Andrzej Zagórski ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Surrounding Medium ◽  
Operating Conditions ◽  
Small Samples ◽  
Destructive Testing ◽  
Element Analysis ◽  
Qualified Personnel ◽  
Oil Pipelines ◽  
Pipeline Networks ◽  
Non Destructive

In this paper a newly environmental friendly Non-Destructive Testing (NDT) method for underground oil and gas pipeline networks is proposed. A suitable equipment extracts small samples of material from installed buried pipes for mechanical testing. Numerical calculations using Finite Element Analysis (FEM) proves that decreasing wall-thickness pipes is safe for in-field operating conditions. Nevertheless, those locations from where samples are cut should be monitored. For instance by means of Acoustic Testing (AT) system. New way of placing sensors is proposed. Sensors are introduced inside the pipe so that any acoustic wave changes from surrounding medium can be measured. In this type of AT a straightforward procedure must be followed to install sensors on pipe. Therefore, there is no need to uncover tested areas with qualified personnel. The research showed that the signals recorded from internal sensors are comparable to those results extracted from external ones. The study also revealed lower vulnerability to acoustic interference of the sensor placed inside the pipeline.

Pressure Maintenance and Improving Oil Recovery by Means of Immiscible Water-Alternating-CO2 Processes in Thin Heavy-Oil Reservoirs

2013 ◽  
Vol 16 (01) ◽  
pp. 60-71 ◽  
Author(s):  
Sixu Zheng ◽  
Daoyong Yang
Keyword(s):  
Oil Recovery ◽  
Heavy Oil ◽  
Oil Production ◽  
Horizontal Wells ◽  
Operating Conditions ◽  
Oil Reservoirs ◽  
Oil Saturation ◽  
Water Alternating Gas ◽  
Heavy Oil Reservoirs ◽  
Water Cut

Summary Techniques have been developed to experimentally and numerically evaluate performance of water-alternating-CO2 processes in thin heavy-oil reservoirs for pressure maintenance and improving oil recovery. Experimentally, a 3D physical model consisting of three horizontal wells and five vertical wells is used to evaluate the performance of water-alternating-CO2 processes. Two well configurations have been designed to examine their effects on heavy-oil recovery. The corresponding initial oil saturation, oil-production rate, water cut, oil recovery, and residual-oil-saturation (ROS) distribution are examined under various operating conditions. Subsequently, numerical simulation is performed to match the experimental measurements and optimize the operating parameters (e.g., slug size and water/CO2 ratio). The incremental oil recoveries of 12.4 and 8.9% through three water-alternating-CO2 cycles are experimentally achieved for the aforementioned two well configurations, respectively. The excellent agreement between the measured and simulated cumulative oil production indicates that the displacement mechanisms governing water-alternating-CO2 processes have been numerically simulated and matched. It has been shown that water-alternating-CO2 processes implemented with horizontal wells can be optimized to significantly improve performance of pressure maintenance and oil recovery in thin heavy-oil reservoirs. Although well configuration imposes a dominant impact on oil recovery, the water-alternating-gas (WAG) ratios of 0.75 and 1.00 are found to be the optimum values for Scenarios 1 and 2, respectively.

The Model of Wax Precipitation and Experimental Validation

2012 ◽  
Vol 463-464 ◽  
pp. 1182-1185 ◽  
Author(s):  
Bing Qiang Zhang ◽  
Da Shuai Xue ◽  
Ji Cheng Yang
Keyword(s):  
Rheological Property ◽  
Pour Point ◽  
Wax Deposition ◽  
Wax Precipitation ◽  
Oil Pipeline ◽  
Waxy Oil ◽  
The Past ◽  
Oil Pipelines ◽  
Experimental Values ◽  
Pipeline Safety

A comprehensive review of literature concerning rheological property, and wax deposition during involving the pipeline safety problems is presented. The deposition and gelation of waxy oil pose great flow assurance risks, especially in submarine oil pipeline. Even though there have been a lot of studies and breakthroughs in understanding the wax precipitation and deposition in the past few years, there still continue to be some challenges that have remained unsolved. In order to well understand the rheological property of the crude oil, First of all, the issue need to be solved is study the wax precipitation property of the oil. In this paper, an accurate model of wax precipitation in laboratory condition undergoing a cooling process is established. And then we predicted the wax appearance temperature, pour point and the weight of the wax appearance about the oil sample. Here, the calculated results of model are much close to the experimental values, which shows that the model of wax precipitation developed is correct and reasonable. By accurate prediction the WAT, pour point, we can well understand the rheological property, which will help the operators make an impeccable flow restart plan for the planned or emergency production shut-down of waxy oil pipelines

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