Wax Appearance Temperature Research Articles

Systematic Study of Temperature and Different Types of Mixing in Paraffin Deposition Test Methods.

Paraffin fouling deposition is a common issue in oil production that leads to constrictions within the system wherever the system temperature drops below the wax appearance temperature (WAT). Chemical mitigation of these issues often relies on various laboratory equipment for product selection, but often the test conditions chosen are not representative of the field; therefore, the resulting deposit generated may give misleading results. In this article, our aim is to investigate how the use of different laboratory techniques can be utilized to generate a field-representative wax deposit. Our study includes the traditional cold finger (CF) apparatus, the coaxial shear cold finger (CSCF), and the dynamic paraffin deposition cell (DPDC), a test method developed in house. The pieces of equipment use similar temperature-driven deposit formation to measure fouling but with very different mixing conditions. The study of paraffin deposition at narrow temperature gradients with these techniques showed similar trends for deposit weight when compared to the fouling factor obtained using a common oil and the Para-window technique presented in a previous study. Significantly, it was observed that for all of the laboratory techniques used, different sample homogenization/mixing mechanisms did not affect the carbon chain distribution of the most insoluble and problematic high-molecular-weight wax (≥n-C35) but did affect the shorter chain composition (i.e., those that are most prevalent in the parent crude oil). The results confirm that temperature is the main driver dictating the nature of the most field-representative deposit characteristics using the laboratory test systems available. This presents the opportunity to gain better insights into paraffin deposition in the laboratory and prepares us to develop better screening capabilities in order to meet current and future paraffin challenges faced in the field.

Investigating molecular interaction between wax and asphaltene: Accounting for wax appearance temperature and crystallization

Three modes will improve the interaction of the wax-asphaltene molecules that eventually increase wax appearance temperature (WAT) within crude oil. The first mode takes place when the wax is composed of long-chain alkanes, and its aromatic compounds are low, and adjacent hydrogens in its constituent aromatic rings are substituted with long-chain paraffin. The second condition is when the wax is formed from low carbon number alkanes. In this case, the lower the asphaltene aromaticity and the carbon number of side alkyl chain, the higher its interaction with wax would be. The third approach occurs if naphthenic or aromatic structures exist in wax, and asphaltene aromatic rings are arranged as peri-condenses. Higher interaction of wax and asphaltene reduces wax crystals’ size. The presence of polar compounds in the molecular structure of the wax and asphaltene does not affect WAT, but the size and morphology of crystals alter in microscopic images.

Effect of poly (ethylene-butene) and nano-aluminium oxide blend on the viscosity of Nigerian crude oil

Wax deposition in production tubing and pipelines is very critical in Nigeria petroleum industry. It can lead to a reduction in production, shut-in of wells, choking of flow lines, failure of downhole equipment, increased power requirement and loss in revenue. In the bid to address this issue, a Niger Delta crude oil sample was characterized in this study to know its wax deposition tendency and other chemical properties. The effect of temperature on the viscosity of the crude oil sample was studied, and the degree of viscosity reduction (DVR) of the crude oil sample in the presence of poly (ethylene-butene) (PEB) and nano-aluminium oxide (Al2O3) blend at different temperatures was evaluated. 100 ppm of nano-Al2O3 blend with 1000 ppm, 2000 ppm and 5000 ppm of PEB, respectively, was added to the crude oil sample at different temperatures, and the degree of viscosity reduction (DVR) in each blend at 10 °C, 15 °C, 20 °C, 30 °C and 35 °C was evaluated. The blend with 2000 ppm of PEB with 100 ppm nano-Al2O3 is the best for offshore application as it gave the highest DVR of 77.9% and 73.7% at 10 °C and 15 °C, respectively, while the other blends gave a DVR of about 70% at 10 °C and 15 °C. As the crude sample temperature approached the wax appearance temperature of 29 °C, the DVR of PEB/Al2O3 blend drastically reduced. PEB/Al2O3 blend inhibited wax precipitation, and at low temperatures, a significant reduction in the viscosity of the crude oil sample was observed, which makes it a good recommendation for offshore application.

Investigation of the Effects of Flowline Sizes, Flow Rates, Insulation Material, Type and Configuration on Flow Assurance of Waxy Crude

The recovery of hydrocarbons has gone into deep and ultra-deep waters. Typically, operations from such an environment make the system susceptible to flow assurance challenges. Operations with long subsea flowlines need special attention with respect to flow assurance problems, especially with respect to wax deposition and risk of hydrate formation. As a result, during such operations, it becomes very crucial to evaluate the flowline sizes, flow rates and subsea flowline lengths to minimize flow assurance problems. For the wax deposition control, the operating temperature must be maintained above wax appearance temperature (WAT) by either insulation or electrical heating depending on the cost and energy efficiency factors. In this study, several multiphase simulations were carried out using PIPESIM software to investigate the effects of flowline sizes, flow rates, insulation material, type and configuration on flow assurance of waxy crude over 10.2 km between the wellhead and the first stage separator on the platform. Considering the implications of these factors for flow assurance. The data and results obtained from this study suggest that line size of 0.29 m, the flow rate of 3280 m 3 /d, poly-urethane foam, and pipe-in-pipe insulation type are favourable to flow assurance of waxy crude with respect to maintaining the temperature of the fluids above the wax appearance temperature of 26 o C; and also to deliver the fluids to the platform at the recommended pressure of over 11 bar. Keywords: Waxy Crude. Flow Assurance. Flow Rates. PIPESIM software, wax control. DOI: 10.7176/ISDE/11-3-02 Publication date: April 30 th 2020

Effects of Waxes and the Related Chemicals on Asphaltene Aggregation and Deposition Phenomena: Experimental and Modeling Studies.

Solid deposition during production, transport, and storage of crude oils leads to significant technical problems and economic losses for the oil and gas industry. The thermodynamic equilibrium between high-molecular-weight components of crude oil, such as asphaltenes, resins, and waxes, is an important parameter for the stability of crude oil. Once the equilibrium is disturbed due to variations in temperature, pressure, and oil composition during production, the solubility of high-molecular-weight waxes decreases. This results in a decrease in the wax appearance temperature (WAT) and the deposit of wax onto solid surfaces. On the other hand, under these conditions, asphaltenes do not interact sufficiently with the resins/waxes and tend to flocculate among themselves and form asphaltene nanoaggregates. The role of waxes during the asphaltene aggregation and deposition has not been appropriately explained yet. The objective of this research study is to describe the interaction of asphaltenes and waxes and subsequently address the specific example of an asphaltenic oil commingled with a wax inhibitor-containing oil during the combination of different oil streams. It is a crucial building block for the development of a suitable and cost-effective strategy for the handling of wax/asphaltene associated flow assurance problems. In this work, the quartz crystal microbalance (QCM) technique has been used for the first time to investigate the effect of waxes and related chemicals, which are used to mitigate wax deposition, on asphaltene aggregation and deposition phenomena. Asphaltene onset point and asphaltene deposition rate have been monitored using QCM at high pressure–high temperature (HPHT) conditions. This study confirms that the different wax inhibitor chemistries result in significant differences in the pour point decrease and viscosity profiles in crude oil. Different wax inhibitors also showed different outcomes regarding the asphaltene deposition tendency. A comprehensive modeling study has also been conducted for mechanistic investigation of experimental results. In this regard, the perturbed chain statistical associating fluid theory equation of state (PC-SAFT EoS) was utilized to model the systems.

Characterizing the wax-asphaltene interaction and surface morphology using analytical spectroscopy and microscopy techniques

In this study, the effect of wax-asphaltene molecular interaction and crude oil property on the amount of wax appearance temperature (WAT) along with the size and morphology of the wax crystals were investigated. For this purpose, three crude oil samples selected, and their WAT value is determined using a cross-polarized microscope (CPM) method. The spectroscopy analysis of crude oil samples demonstrated that the morphology of wax crystals in CPM images depends mainly on the functional groups existing in crude oil. The presence of polar functional groups such as hydroxyl, increasing the aliphatic compounds, and reducing the percentage of aromatics in crude oil leads to wax crystals to become rounded, and their uniformity rise. The size of the wax crystals is associated with the crude oil aromaticity index. Increasing the aromatic rings in the structure of crude oil creates larger wax crystals. However, the amount of WAT depends on the molecular structure of the wax and asphaltene besides their interaction. If the wax molecule is mainly paraffinic and the percentage of cyclic compounds is low, the interaction between the poly-aromatic asphaltene molecule with the wax molecules significantly decreases; thus, the asphaltene cannot act as a nucleation point for the wax particles, and the WAT value reduces. The shape of the wax particles in SEM images is closely related to its molecular structure. If the wax constituent of crude oil is microcrystalline, the interaction between the wax and asphaltene increases. Therefore, the wax particles will be observed rounded under SEM. If the wax has both cyclic and paraffinic compounds, its crystals will be seen in the plate-type form. Furthermore, if the wax constituent is macrocrystalline, the wax particles will have a hive-type shape and cover the entire surface of the image.

Predicting wax appearance temperature and precipitation profile of normal alkane systems: An explicit co-crystal model

Wax precipitation is a major flow assurance issue for petroleum production, oil blending, downstream processing, and oil products usage. While numerous thermodynamic models have been proposed to calculate wax appearance temperature (WAT) and precipitation profile at temperatures below WAT, the existing models are correlative in nature and fail to comply with phase behavior experimentally observed for wax precipitation. This work presents a predictive thermodynamic model for wax precipitation based on an explicit co-crystal formation assumption for precipitated wax, a treatment consistent with experimental findings. With a simple Flory-Huggins expression accounting for the liquid phase nonideality and the treatment of lamella structure for wax precipitation below WAT, the model satisfactorily predicts WAT at low pressures for multicomponent paraffin mixtures and wax precipitation amounts and contents as the temperature drops below WAT.

Monitoring and Detection of Paraffin Wax Deposition Process Based on Ultrasonic Analysis.

Paraffin wax deposition is the most frequent flow assurance problem in oil production fields. It disrupts stable oil production, and a considerable amount of time and money are spent ameliorating on-site problems. To prevent and mitigate paraffin wax deposition, it is necessary to proactively identify the conditions under which paraffin wax is deposited. Furthermore, monitoring and detection techniques are required to determine the efficacy of the technical measures applied. This study proposes a method based on acoustic velocities obtained by ultrasonic monitoring and detection to estimate the following three temperature elements: (1) wax appearance temperature of oil containing paraffin wax, (2) temperature at which the growth of paraffin wax deposits is activated, and (3) temperature at which the paraffin wax deposits begin to age. An experimental system comprising an ultrasonic transducer and a temperature sensor were set up, and the temperature gradient of the analyzed fluid sample was controlled by continuously circulating an isothermal fluid. Based on real-time monitoring, data measurements were made, and variations in the acoustic velocity of fluid samples were measured. A paraffin wax deposition experiment was conducted using synthetic waxy oil samples with paraffin solid contents of 5 wt.% and 15 wt.%, respectively. Q-factors were calculated based on the spectral ratio method, and wavelet characteristics were analyzed according to temperature changes, to estimate wax appearance temperature. Results show that the method proposed in this study estimates wax appearance temperature in a similar measurement range as conventional methods and enables the life cycle of paraffin wax deposition to be determined through monitoring and detection.

An Experimental Study on Evaluation of Factors Influencing the Viscosity and Viscoelastic Properties of Waxy Crude Oil

The influences of several operating factors on the viscosity of the Isfahan refinery waxy crude oil sample are studied through conducting some rheological shear rotational tests. The Taguchi design method is adopted to determine the impact of factors such as shear rate, temperature, cooling rate, wax content, and asphaltene content on the viscosity of the waxy crude oil. The results show that temperature with a contribution of 53.61% is the most influential factor. The wax content, shear rate, and asphaltene content have a contribution of 20.86, 14.75, and 3.11% respectively. The cooling rate does not have a statistically significant effect on the viscosity. The results of the rheological oscillatory tests confirm that the temperature and wax content change the viscoelastic properties of the waxy crude oil completely. An increase in the wax content from 12 to 22 wt.% raises the wax appearance temperature (WAT) from 19.1 to 34.9 °C and improves the gel point from 13 to 34.1 °C. By decreasing the temperature or increasing wax content, the viscoelastic nature of the oil sample changes from a viscoelastic fluid to a viscoelastic solid.

Study on wax precipitation characteristics of wax deposit in pipes

AbstractWax deposit properties are a significant concern in pipeline pigging during waxy crude oil transportation. In the present work, the impacts of flow conditions and oil properties on the wax precipitation characteristics of wax deposits are investigated. A flow loop apparatus was developed to conduct wax deposition experiments using four crude oils collected from different field pipes. The differential scanning calorimetry (DSC) technique was employed to observe the wax precipitation characteristics of crude oil and wax deposit. The results show that the wax content and the wax appearance temperature (WAT) of the deposits increase with shear stress and radial temperature gradient, and decrease with radial wax molecule concentration gradient near the pipe wall. The DSC tests on the wax deposits revealed that the deposit wax content is strongly correlated to the oil wax content. Furthermore, an empirical correlation was developed to predict the wax content and the WAT of the wax deposit. Verification of the empirical correlation using the different oils indicated that the average relative error of the wax content prediction and average absolute error of WAT prediction were 13.2% and 3.6°C, respectively.

Review of Solvents Based on Biomass for Mitigation of Wax Paraffin in Indonesian Oilfield

This paper presents a review of the expectations and challenges of using biomass in the prevention and slowing of paraffin wax deposition that takes place during the crude oil production process. The inhibition of the deposition process involves the use of solvents from biomass that are generally available around the crude oil production field. The processes used to scale down the precipitation of wax include mixing crude oil with the manufacturer’s solvent composed of toluene and xylene. The goal is to assess solvents sourced from biomass that are capable to slow down the wax deposition process. Wax appearance temperature is an important characteristic to evaluate the possible wax precipitation of a given fluid. Wax precipitation can be reduced by using some chemical additives, often called the pour point depressant. This additive is expected to be produced from local biomass which can compete with solvents currently produced on the market.

Prediction of Wax Appearance Temperature Using Artificial Intelligent Techniques

The paraffin particles can promote and be involved in the formation of deposits which can lead to plugging of oil production facilities. In this work, an experimental prediction of wax appearance temperature (WAT) has been performed on 59 Algerian crude oil samples using a pour point tester. In addition, a modeling investigation was done to create reliable WAT paradigms. To do so, gene expression programming and multilayers perceptron optimized with Levenberg–Marquardt algorithm (MLP-LMA) and Bayesian regularization algorithm were implemented. To generate these models, some parameters, namely density, viscosity, pour point, freezing point and wax content in crude oils, have been used as input parameters. The results reveal that the developed models provide satisfactory results. Furthermore, the comparison between these models in terms of accuracy indicates that MLP-LMA has the best performances with an overall average absolute relative error of 0.23% and a correlation coefficient of 0.9475.

Modelling of wax deposition by perturbed hard sphere chain equation of state

This article presents a model to predict the wax appearance temperature (WAT) and the quantity of wax deposition in eight different n-alkane mixtures using a correlative technique. The perturbed hard sphere chain equation of state (PHSC EoS) was employed in conjunction with the multi-solid model to describe the liquid-liquid and solid-liquid equilibria. The results are compared with experimental data. The results showed that PHSC EoS for some mixture of n-alkanes can perceptibly outperform the sole solid solution theory, improving the modelling of wax deposition quantities and wax appearance temperature by giving predictions closer to experimental values.

Screening of the factors for novel pour point depressant copolymer synthesis to improve the copolymer yield

Pour point depressants (PPDs) commonly used in the oil and gas industry as a chemical wax inhibitor to control the temperature of the crude oil below their wax appearance temperature (WAT) points, and to improve the flowability of crude oil. In this study, different conditions of Stearyl Acrylate-Behenyl Acrylate (SABA) copolymer were synthesized by free-radical solution polymerization method at different range conditions of polymerization. Four factors considered during the synthesize of the copolymer are the mass ratio of monomers (1:1, 1:2, 1:3, 2:1, and 3:1 wt%), reaction temperature from 60 to 100 °C, the concentration of initiator from 0.5 to 2.5 wt% and reaction time from 5 to 9 hour. The results showed that the best conditions to obtain the highest yield of SABA copolymer were at the mass ratio of monomers of 1:1 (w/w), the reaction temperature of 90 °C, the reaction time of 7 h, and concentration of initiator at 1 wt%.

Characterization of the wax precipitation in Iranian crude oil based on wax appearance temperature (WAT): The influence of ultrasonic waves

Abstract In this study, the effect of ultrasonic waves on the wax appearance temperature (WAT) of a crude oil sample was investigated. For this purpose, the crude oil was exposed to ultrasonic radiation at 2, 4, 6, 8, and 10 min. Then, the WAT of each sample was measured using the cross polarized microscope (CPM) method. The WAT was reduced to 8 °C and 12 °C at 4–8 min and 10 min, respectively. The origin of this reduction by ultrasonic radiation were studied by Fourier-transform infrared (FTIR) spectroscopy analysis. Because of the ultrasonic radiation, the first heavy crude compounds are cracked to lighter compounds, which reduces the side alkyl chain index in the FTIR spectra. Depending on the temperature of the crude oil after the irradiation, some light petroleum components, such as aliphatic components evaporated, resulting in the reduction of the aliphatic index calculated from the FTIR spectra. The wave radiation causes the wax crystals to become smaller, and their diameter dispersion reduces. The crystals were seen as rod-type before the irradiation, but the ultrasonic radiation caused the wax crystals to be rounded. Moreover, the wax crystals became morphologically more uniform. These waves, because of their high energy levels, cause changes in the percentage of saturate, aromatic, resin, and asphaltene (SARA) components of the crude oil, that are effective in altering the WAT. The aromatic compounds of the crude oil are pyrolyzed in two ways. First, in the presence of the saturate compounds, they are converted to resin. The resin, as a surfactant, reduces crystallization seeds in the oil and reduces the WAT point. Secondly, the aromatic compounds are first converted into the liquid saturate, and they evaporate if energy is supplied. The asphaltenes are also sensitive to pyrolysis by transferring energy into the oil and converting into the saturate compounds, especially methyl. Increasing the resin and light components within the structure of oil, such as paraffin, and reducing the aromatic and asphaltene compounds eventually reduced WAT. Finally, the shape of wax particles, isolated by IP143 method, was analyzed by scanning electron microscopy (SEM) imaging. The high-energy ultrasonic waves caused the average size of wax grains to reduce, the space between them to be greater, and the form of seeds changed from rounded to snow-like and irregular. Also, after the irradiation, bright spots were observed at the surface of the wax grains, which is related to the presence of heavy metals.

Effect of Emulsified Water on Gelled Pipeline Restart of Model Waxy Crude Oil Cold Flows

Recent work has shown the promise of cold flow technology for transporting waxy crude oils below their wax appearance temperatures. The thermal flux that results due to the difference between the t...

Investigations of temperature and dilution effect on rheological properties of waxy crude oil

The purpose of the paper is to study the effect of temperature and hydrocarbon solvent addition on thixotropy of waxy crude oil. Oil is a complex multicomponent hydrocarbon system. There are many interactions between wax and asphaltene, wax and aromatics, asphaltene and resins in original oil. For example, the dispersion of asphaltenes is known to be influenced by resins. The resins are adsorbed onto the surface of the asphaltenes, whereby the asphaltenes are not aggregated. Wax is adsorbed by fine asphaltene particles and wax appearance temperature (WAT) observed at low temperature (formed wax crystals too small to be detected by measuring system). The authors of the paper have studied the separate effect of two solvents (kerosene and diesel fuel), wax concentration and impurities (kaolinite) on WAT to understand how all these factors affect WAT in wax-bearing solutions individually. Wax-bearing solutions in wax concentration range from 10 to 60% by weight were investigated by the visual and rheological methods under atmospheric pressure. It is shown that the diesel-based solutions have higher WAT than the kerosene-based solutions. Studies have shown that the increase in wax concentration in solution leads to an increase in WAT. The paper describes that the addition of impurities (kaolinite) to the solutions resulted in an increase in WAT. Besides, it is shown that WAT obtained by rheological method is higher on average of 1 °C than WAT obtained by visual method. The authors suggested that under constant other conditions (pressure, resin and asphaltenes content, etc.) an increase in wax content in oil and the content of impurities will lead to an increase in WAT. The scientific basis for this conclusion is that, in the future we can, adding or removing from solution hydrocarbon components, with certain assumptions, simulate the properties of oil. In particular, this will allow us to study separate interactions between the wax and asphaltene, wax and aromatics, and wax and naphtha compounds, and abstract away from other factors. The waxy crude oil production in the Samara region is complicated by impurities entrainment and non-Newtonian properties of oil. The investigations of waxy crude oil were provided with light scattering method (in near infrared region), microscopy under high pressure with the grain size analysis (visual) and a rheological method. We obtained the unique «viscosity superanomaly» discovered by Vinogradov and Malkin (Rheol Acta 5(3):188–193, 1966) at low temperatures and shear stress by rheological method under atmospheric pressure. The area of the hysteresis loop on the flow curve increases as the temperature decreases, which is caused by the formation of the lattice by wax. We have also shown that the use of solvent and the increase in temperature allow to reduce «viscosity superanomaly». Simultaneous use of light scattering and microscopy under high-pressure methods allows increasing in accuracy of measuring. For waxy crude oil, there will also be a difference between rheological and visual methods of WAT measuring, as these methods have different sensitivity limits. Besides, the study showed that addition of N2 and CO2 to oil leads to decrease in WAT. However, it is necessary to provide a number of additional studies before gas injection projects in the field. For example, it is shown that CO2 injection leads to asphaltenes precipitation in oil by many scientists. Novelty of the paper consists in investigation of rheological properties of waxy crude oil of the Samara and the effect of nonhydrocarbon gases on WAT. In this study, unique flow curves of oil of the Samara region were obtained.

Wax deposition mechanisms and the effect of emulsions and carbon dioxide injection on wax deposition: Critical review

Wax deposition inside the tubing walls endures being a critical operational challenge faced by the petroleum industry. The build-up of wax deposits may lead to the increase of pumping power, as well as the decrease of flow rate or, even, to the total blockage, with production losses and high operational costs. The current paper is a critical review of the main deposition mechanisms involved in wax deposition. Most of wax deposition models regard molecular diffusion as the dominant wax deposition mechanism. However, there are other deposition mechanisms which can also play a role. As most oil fields produce water along with crude oil, the deposition process for oil-water emulsions has also been investigated. Furthermore, carbon dioxide injection effects upon wax appearance temperature along its current applications onto wells have been reviewed. Having a total awareness of the wax deposition mechanisms background is the key factor to prevent the wax precipitation and control the deposition of solid wax crystals.

Influence of Wax Precipitation on the Impedance Spectroscopy of Waxy Oils

Impedance spectroscopy (IS) is a widely used nondestructive and high-throughput experimental technique for the characterization of electrical properties of materials. In the petroleum industry, IS is frequently employed to determine the electrical properties of asphaltenes and resins. The electrical properties of waxy crude oils, which correlate significantly with the flowability, however, have received little to no attention in the existing investigations. In this work, we inspected the influence of wax precipitation on IS of waxy crude oil for the first time. The investigation was carried out in a frequency range of 2 × 10–1 to 2 × 104 Hz and a temperature range of 5–60 °C. It was discovered that the Nyquist diagram representing the electrical response of waxy oil evolves from one semicircle to two semicircles as wax molecules precipitate at temperatures below the wax appearance temperature. IS of waxy crude oil can be reproduced by an equivalent circuit model composed of two serially connected constant phase element-ideal resistance combinations (Rbulk|Qbulk – Rwax|Qwax). It was found that the resistor-like contribution from wax in the equivalent circuit model, Rwax, increases with the amount of precipitated wax, whereas the capacitor-like contribution in the equivalent circuit model, Qwax, decreases with the amount of precipitated wax. Furthermore, the flow property of waxy oil, such as viscosity, can be related to the conductivity according to the fractional Walden rule. The entire viscosity–conductivity relationship can be divided into three regions, and each segment of the relationship can be fitted by the fractional Walden rule.

Influence of solvent solubility parameter on the performance of EVA copolymers as pour point modifiers of waxy model-systems

High molar mass paraffins in the crude oil solidify with the reduction of temperature during offshore production, which can reduce production or even block outflow lines. Polymers can be used to inhibit the wax deposition. However, the efficiency of the additives depends on the type of oil and, because it is a complex mixture, this relationship still needs further investigation. The aim of this work is to evaluate the influence of different types of compounds present in petroleum on the action of poly(ethylene-vinyl acetate) as pour point reducers using model systems of paraffins in solvents. The study was carried out based on results of pour point, wax appearance temperature and polymer-solvent interaction. The results showed that only the asphaltenes (C5I and C7I) changed the pour point to lower values. The other compounds, such as naphthalene, naphthenic acid and adamantene, at the concentration used of 1 wt/v%, did not alter the melting point of the model systems or interfere with the additive action. On the other hand, by analyzing the influence of the solvent composition, it was observed that: (i) the wax solubility in the medium affected the WAT but did not affect the pour point (the higher the solubility of the paraffin in the medium, the lower the WAT is); and (ii) the solubility of the additive in the solvent medium did not affect the WAT but significantly affected the pour point (the higher the polymer-solvent interaction, the lower the pour point of the model-system containing the additive).