Crude Oil Wax Research Articles

Modification of Nanyang crude oil by a functional magnetically responsive flow modifier in synergy with magnetic field

Abstract Nanyang crude oil is classified as high wax crude oil. It has severe wax deposition and poor low-temperature fluidity, which pose a major risk to the safety of pipeline transportation of wax-containing crude oil. A large-size polymer-coated magnetic nanosphere was created by dispersion polymerization employing methyl methacrylate, nano-iron oxide, tetraethoxysilane, and dodecyltriethoxysilane as raw materials to address the aforementioned issues.Ethylene-vinyl acetate copolymer was compounded to provide a useful magnetic response flow modifier.Using FTIR and ESEM, the polymer grafted on the iron oxide nanosphere’s surface was shown. After evaluating the functional magnetic response flow modifier’s impact on the yield stress and viscosity of a Nanyang crude oil, the effect of the magnetic field was introduced to analyze the functional magnetic response flow modifier’s synergistic effect on viscosity and yield stress. The results show that the functional magnetic response flow modifier may greatly lower yield stress and viscosity when compared to the EVA pour point depressant. Additionally, applying an alternating magnetic field could amplify the functional magnetic response flow modifier’s beneficial effects on Nanyang crude oil.

Study on the Effect of Nano Pour Point Depressant on Wax Oil Crystallization

The influence of nano pour point depressant (NPPD) on crude oil containing wax is primarily manifested through their interaction with the wax constituents. This study examines the depressant's effects using a polarizing microscope and an atomic force microscope (AFM) to assess morphological and structural changes in the wax crystals within the oil, both before and after the addtion of the NPPD. Additionally, a surface tensiometer measured surface tension, while a rheometer evaluated viscosity and modulus alterations. These methods facilitated insights into NPPD's mechanistic effects. The interaction process between crude oil wax crystal molecules and the main components of NPPD was simulated using JOCTA molecular dynamics simulation software, and the highest interaction strength between benzenesulfonic acid groups and crude oil wax crystal molecules was determined. The findings indicate that the addition of the NPPD alters the growth patterns and crystalline structure of the wax in the oil. Initially, the wax crystals present as flaky, predominantly single molecular layer lamellae with a thickness of approximately 100 nm. Post-treatment, the wax crystals adopt a flattened lamellar configuration, composed of multilayer lamellae, with a reduced thickness of within 10 nm and exhibiting short-range order. AFM height maps reveal an increase in the average roughness of the wax oil correlated with the addition of the NPPD across different sampling lengths. Surface tension measurements demonstrate that the wax oil doped with the NPPD exhibits lower surface tension than undoped oil, with the surface tension decreasing as the temperature increases.

Wax appearance temperature in crude oils measured by surface plasmon resonance

To predict and quantify the wax appearance temperature in crude oils, we proposed and implemented a well-explored sensing method known as surface plasmon resonance. This phenomenon occurs when an incident light beam couples into a metallic surface. As sensing method, this phenomenon has been widely used in biosensing applications. In this research, we showed the effectiveness of the surface plasmon resonance sensing technique in hydrocarbon sensing in general and in crude oil wax appearance prediction in particular. To the authors knowledge, this is the first exploration of monitoring wax deposition events from crude oil using surface plasmon resonance measurements. A compact optical sensor was developed from an ultra-thin layer of gold deposited on a sapphire prism and supported by a new data analyzing metric to analyze the acquired reflected beam intensity profile and detect the precipitation of crude oil wax or other hydrocarbon particles under varying-temperature and low-pressure conditions. The obtained wax appearance temperatures using the introduced on-site method were found to be comparable with the literature measurements using the common in-lab Cross-Polarization Microscopy method.

Evaluation of Crude Oil Wax Dissolution Using a Hydrocarbon-Based Solvent in the Presence of Ionic Liquid

The current alternative of using aromatic-based wax soak solvents has been found to be hazardous and imposes a high cost on field expenditures. These solvents are widely used in the oil and gas industry to soften up wax before the pigging process. However, their impacts on the environment are quite concerning. Plus, they also impose hazardous exposure and are found to be damaging to both plastic and rubber hoses. To replace the current alternative with other hydrocarbon-based wax soak solvents, ionic liquids were found to have the capability to increase the solvent power capabilities and the efficiency of wax soak solvent in dissolving heavy crude oil. To optimise the application of hydrocarbon solvents and ionic liquid in wax dissolution, the affinity of ionic liquids in three solvents was studied. The solvents were condensate, ethyl acetate, and xylene. It was found that from four types of ionic liquids tested, only BMIMCL and HMIMBr were miscible in all three of the solvents used. Dissolution of hard deposited paraffin wax in condensate, ethyl acetate and xylene was conducted using the spectral analysis method, and it was found that the dissolution of paraffin wax was greatest in ethyl acetate. However, enchantment on wax dissolution was also observed for gas condensate and xylene. The wax soaking time was also optimised, in which the dissolution of wax was found to reach a saturation level when the wax had been soaked for over 90 min in the solvents, especially for gas condensate. Further study on the effect of ionic liquid introduced alongside condensate, ethyl acetate and xylene, aiming to enhance the solvent power, was also conducted using the spectral analysis method. The introduction of ionic liquids to all hydrocarbon-based wax soak solvents used in this project was proven to significantly increase the UV-VIS absorbance of the extracted solvents after paraffin wax had been soaked for 30 min.

Crude oil wax: A review on formation, experimentation, prediction, and remediation techniques

Wax deposition during crude oil production, transportation, and processing has been a headache since the early days of oil utilization. It may lead to low mobility ratios, blockage of production tubing/pipelines as well as fouling of surface and processing facilities, among others. These snags cause massive financial constraints increasing projects' turnover. Decades of meticulous research have been dedicated to this problem that is worth a review. Thus, this paper reviews the mechanisms, experimentation, thermodynamic and kinetic modeling, prediction, and remediation techniques of wax deposition. An overall assessment suggests that available models are more accurate for single than multi-phase flows while the kind of remediation and deployment depend on the environment and severity level. In severe cases, both chemical and mechanical are synergistically deployed. Moreover, future prospective research areas that require attention are proposed. Generally, this review could be a valuable tool for novice researchers as well as a foundation for further research on this topic.

Study on the viscoelastic-thixotropic characteristics of waxy crude oil based on stress loading

High waxy crude oil occupies an important proportion in oil resources, and its output is increasing year by year. At the temperature below the wax precipitation point, the wax in crude oil will precipitate and cross-link to form a spatial network structure, resulting in the gelation of crude oil. Once crude oil is gelled, it will exhibit viscoelastic-thixotropic characteristics, which will seriously affect the safety of crude oil pipeline transportation. In this paper, based on the principle of mechanical analogy, the elasticity, viscosity and structural strength of the gelled crude oil are characterized by springs, viscous pots, and structural parameters, respectively. On this basis, the viscoelastic-thixotropic model of waxy crude oil with 9 parameters is established. Meanwhile, the model applicability is verified by experimental data using two waxy crude oils under constant shear stress, shear stress step increase and shear stress hysteresis. Compared with the models in literatures, our model has clear physical meaning, relatively few parameters and high prediction accuracy.

Enhance flows of waxy crude oil in offshore petroleum pipeline: A review

In the petroleum industry, the transport of offshore crude oil via pipelines may suffer damage known as wax precipitation. This reduces the flow capacity of the crude oil, reducing its transport efficiency. Under extreme conditions, this may also result in serious damage to equipment. To help alleviate this problem, the petroleum transport and flow characteristics of offshore waxy crude oil in pipelines are investigated, together with the development of several options to help minimize wax precipitation. This paper reviews the current research status for reducing wax precipitation and enhancing crude oil flow in offshore pipelines. Specifically, reducing the viscosity of waxy crude oil, strengthening the process technology of the pipeline and the related flow mechanisms are each investigated. This paper also identifies and discusses areas of study that require further investigation. • Offshore crude oil wax deposition is generated by the precipitation of wax crystals in crude oil. • DRAs, PPD, microbial and hydrate inhibitor decrease the viscosity by reducing the generation of wax crystals. • Skin effect electrical heat tracing increase the temperature of pipeline internal to reduce wax deposition. • Inner wall coating reduces the flow resistance of pipe internal to enhance flows of crude oil. • Hernandez Model, Singh Model and Rygg Model describe the multiphase flow characteristics of crude oil in offshore oil pipelines.

Asphaltene Inhibition and Flow Improvement of Crude Oil with a High Content of Asphaltene and Wax by Polymers Bearing Ultra-Long Side Chain

A high content of asphaltene and wax in crude oil leads to difficulties in the recovery and transportation of crude oil due to the precipitation of asphaltenes and the deposition of waxes. Comb-like polymers were found to be capable of inhibiting the aggregation of asphaltenes and crystallization of waxes. In this work, comb-like bipolymers of α-olefins/ultra-long chain (C18, C22 and C28) alkyl acrylate were synthesized and characterized by FT-IR and 1H NMR spectra. The results show that, for a model oil containing asphaltene, the initial precipitation point (IPP) of asphaltene was prolonged by UV, and the asphaltene particle size was reduced after adding the biopolymers, as revealed by dynamitic light scattering (DLS). The bipolymer containing the longer alkyl chain had a better asphaltene inhibition effect. However, DSC and rheological results show that the wax appearance temperature (WAT) of the typical high asphaltene and high wax content of crude oil was obviously reduced by adding bipolymers with shorter alkyl chains. The bipolymer (TDA2024-22) with a mediate alkyl chain (C22) reduced the viscosity and thixotropy of the crude oil by a much larger margin than others. Compared with the previously synthesized bipolymer with phenyl pendant (PDV-A-18), TDA2024-22 exhibited a better performance. Therefore, bipolymers with appropriate alkyl side chains can act as not only the asphaltene inhibitors but also wax inhibitors for high asphaltene and wax content of crude oil, which has great potential applications in the oil fields.

Combination Treatment of Biosurfactant and Copolymer Alkyl acrylate-Vinyl acetate to Improve the Cold Flow Properties of Waxy Gas Oil

One promising bacterial strain (B3), recovered from petroleum-contaminated soil. The isolate was able to produce biosurfactant. Alkyl acrylate–vinyl acetate copolymer was prepared using varying lengths of the alkyl chain. In this study, the effect of copolymer additives along with biosurfactant on the crude oil wax crystallization method has been examined by solid point test and viscosity index measurement for gas oil. The FTIR spectrum analysis of the biosurfactant showed that it was a polymeric molecule. The application of only copolymer having a side- length of the chain of C13 and C22 reduced the solid point of gas oil by 3 and 9 oC respectively. Furthermore, the same copolymer along with biosurfactant decreased the solid point of gas oil by 15 and 21 oC, respectively. Many copolymer additives blended with biosurfactants, it is assumed that it might be used to slow the formation of wax crystals and shape shorter crystals. Because of this shift in crystal form, wax crystals' capacity to intergrow and interlock is substantially reduced. By increasing the length of the alkyl chain and mixing the copolymer and biosurfactant, the viscosity index of gas oil was raised. The blend P3 and P4 additives were also proved to a better viscosity index modifier at all concentrations in gas oil.

Study on the influence of poly (m-aminophenol) as pour point depressant of paraffinic crude oil

Paraffin wax in crude oil can cause significant problems such as a block of pipelines because of the deposition of wax components during the production, transportation and storage of the crude oil. This work aims to inhibit the deposition of paraffin wax at low temperatures. Poly (m-aminophenol) (PmAP) was prepared by oxidative polymerization technique to act as a pour point depressant (PPDs) for paraffinic crude oil. PmAP was characterized by Fourier Transform Infrared (FTIR) and Scanning Electron Microscope (SEM). The thermal stability of the polymer was investigated by thermal gravimetric analysis (TGA). The effect of the PmAP on the wax crystal modification was studied using photomicrographic analysis. The pour point of paraffinic crude oil was reduced from +42ºC to +6ºC when treated with 2500 ppm of PmAP dissolved in a solvent-based on paraffinic compounds (PONA). The photomicrographs showed that the PmAP has reduced the large size of the spherical wax crystals of the North Silah-1X crude oil this was mainly attributed to the effect of the polar groups of the prepared pour point depressant.

Effect of solid contents and the ratio of EVA/ Octadecylacrylate blends on Paraffin Inhibition and pour point temperature of waxy crude oil

The best performing, most economical and safest is the most desirable triangle in the products used in the petroleum industry. Optimizing the performance of PPD increases the economy of the process; however, excess PPD may have adverse effect. Most of the PPDs have two parts; an oleaginophilic part that co- crystallizes with wax forming components and a polar component that limits the degree of co- crystallization. The present work has main target to study the effect of additives solid contents and composition on the flow characteristics of wax crude oil at low temperature below pour point temperature and paraffin inhibition (PI%). In this respect, different amount of octadecyl acrylate and ethylene vinyl acetate to give different blends with different solid content as follow: PPD-X1(1: 1.4), PPD-X2 (1:0.88), PPD-X3 (1: 1.15), PPD-X4 (1: 1.31), PPD-X5 (1:2) were prepared. These polymeric materials were characterized by FTIR and GPC. The performance of these additives as pour point depressants and flow improver for Egyptian waxy crude oil was evaluated through measurements of pour point paraffin inhibition. It was observed that the PPD-X5 the highest solid content and octa ratio multiple EVA ratio which leads to more effective performance that decrease pour point from 24 to 6 °C with 1200 ppm dose, good handling and highest paraffin inhibition (85 %).

Synthesis of Alkyl Aliphatic Hydrazine and Application in Crude Oil as Flow Improvers

In this paper, alkyl aliphatic hydrazine, which is different from traditional polymer fluidity improver, was synthesized from aliphatic hydrazine and cetane bromide, and evaluated as a pour point and viscosity-reducer depressant for crude oil. The evaluation results showed that alkyl aliphatic hydrazone fully reduced the pour point and viscosity of crude oil with the increase of crude oil fluidity. The viscosity reduction rate of crude oil in Jinghe oilfield was 79.6%, and the pour point was reduced by about 11.3 °C. The viscosity reduction rate of crude oil in Xinjiang Oilfield was 74.7%, and the pour point was reduced by 8.0 °C. The long alkyl chain is beneficial to the eutectic of wax in crude oil, and the polar group inhibits the crystal growth, resulting in the decrease of pour point and viscosity. The waste oil is fully recycled into oilfield chemicals.

Study of linseed oil, its biodiesel and xylene as flow improver for Nigerian waxy crude oils

In this study, the physicochemical properties of linseed and linseed biofuel were studied and their effect on the flow properties of Nigerian waxy crude oil at different volume fractions was investigated. The Nigerian wax crude oil was characterized for its specific gravity, API gravity, wax content, pour point and cloud point. The properties of the linseed oil and linseed biodiesel investigated include: density, specific gravity, viscosity, pour point, cloud point and flash point. Upon esterification of the free fatty acid (FFA) contained in the linseed oil reduced from 3.5 to 0.75 and the viscosity of the seed oil reduces from 2169 to 362 mm2/s. The linseed oil and its biodiesel exhibited similar trend of reduced viscosity at higher shear rate, however, linseed biodiesel demonstrated the lowest viscosities, cloud points and pour points owing to reduced fatty contents. The effect of the linseed oil and its biodiesel on the pour point and cloud point of the waxy crude oil was determined; and the performance compared to that of xylene. A rapid drop in the pour point and cloud point was observed with the wax crude pre-heated with 0.1 v/v linseed oil, its biodiesel and xylene.

Study on Effect of inhibitor on wax precipitation in Iranian oil fields by using differential scanning calorimetry and microscopy

In this study, effect of ethylene vinyl acetate (EVA) as an inhibitor on wax appearance temperature (WAT) of crude oil in the Iranian oil field has been investigated using differential scanning calorimetry (DSC) method. The effect of EVA on the morphology of crude oil wax crystals has been investigated using a system designed to be equipped with an ocular microscope. The EVA inhibitor has a very good performance in reducing the Wax appearance temperature of crude oil and by adsorbing on the growing wax crystals, it prevents the crystallization process and also their connection to each other to form a network structure. By 800 ppm of the EVA inhibitor, the largest decrease occurred in the WAT of crude oil (at the rate of 26.13 ° C) and also smaller crystals and weaker structures were formed at this concentration. Therefore, 800 ppm of EVA inhibitor was selected as an optimal value

Review on the gelation of wax and pour point depressant in crude oil multiphase system

The gelation of waxy crude oil multiphase system can result in the formation of network cementitious structure, which seriously impacts the safe and economic production of crude oil. This paper reviews current experimental, theoretical and numerical results on the gelation of wax in crude oil. For the experimental side, the most important problems are in situ measurement and measurement accuracy. On the theoretical side, the present methods own defects of low accuracy and limited application scope. Numerically, the models are of oversimplification, which are hardly applied to the real production. Besides, as a promising solution, the research progress of crude oil pour point depressant is also reviewed. The molecular design is a powerful approach to develop the optimized pour point depressant. The goals of this paper are to bridge the microscale atomic interactions and the macroscale physicochemical properties of waxy crude oil and pour point depressant, so as to lay a solid theoretical basis for preventing and controlling wax deposition in crude oil. These are beneficial to the future efficient, clean and safe energy production system.

Geochemical characteristics and genesis of crude oils with complex physical properties in the eastern part of the southern gentle slope of Dongying Sag

The crude oil in the eastern part of the southern gentle slope of Dongying Sag has complex physical properties, and various crude oils with different properties such as heavy oil, high sulfur oil, and high wax oil have developed. The complexity of the physical properties reflects the influence of the source rock properties, crude oil migration process, and secondary alteration after accumulation on crude oil characteristics. Through systematic analysis of geochemical data, the formation mechanism of crude oil with these special physical properties has been clarified. The result of hydrocarbon generation at an early stage from source rocks rich in high-sulfur kerogen deposited in a euxinic waterbody is the cause of high-sulfur crude oil with low maturity in Wangjiagang oil field. While the shallow reservoir burial depth and the resulting biodegradation is the mechanism of the formation of high-sulfur crude oil in Le’an oil field with higher maturity. Biodegradation is the main mechanism of the formation of heavy oil, and the recharge of hydrocarbons into the degraded crude oil reservoirs leads to the complication of crude oil density. Both the hydrocarbon generation of organic matter rich in terrestrial higher plants and phase-controlled fractionation during hydrocarbon migration lead to the generation of high wax crude oil.

Microbial Biodegradation of Paraffin Wax in Malaysian Crude Oil Mediated by Degradative Enzymes.

The deposition of paraffin wax in crude oil is a problem faced by the oil and gas industry during extraction, transportation, and refining of crude oil. Most of the commercialized chemical additives to prevent wax are expensive and toxic. As an environmentally friendly alternative, this study aims to find a novel thermophilic bacterial strain capable of degrading paraffin wax in crude oil to control wax deposition. To achieve this, the biodegradation of crude oil paraffin wax by 11 bacteria isolated from seawater and oil-contaminated soil samples was investigated at 70°C. The bacteria were identified as Geobacillus kaustophilus N3A7, NFA23, DFY1, Geobacillus jurassicus MK7, Geobacillus thermocatenulatus T7, Parageobacillus caldoxylosilyticus DFY3 and AZ72, Anoxybacillus geothermalis D9, Geobacillus stearothermophilus SA36, AD11, and AD24. The GCMS analysis showed that strains N3A7, MK7, DFY1, AD11, and AD24 achieved more than 70% biodegradation efficiency of crude oil in a short period (3 days). Notably, most of the strains could completely degrade C37–C40 and increase the ratio of C14–C18, especially during the initial 2 days incubation. In addition, the degradation of crude oil also resulted in changes in the pH of the medium. The degradation of crude oil is associated with the production of degradative enzymes such as alkane monooxygenase, alcohol dehydrogenase, lipase, and esterase. Among the 11 strains, the highest activities of alkane monooxygenase were recorded in strain AD24. A comparatively higher overall alcohol dehydrogenase, lipase, and esterase activities were observed in strains N3A7, MK7, DFY1, AD11, and AD24. Thus, there is a potential to use these strains in oil reservoirs, crude oil processing, and recovery to control wax deposition. Their ability to withstand high temperature and produce degradative enzymes for long-chain hydrocarbon degradation led to an increase in the short-chain hydrocarbon ratio, and subsequently, improving the quality of the oil.

Effects of 4-vinylbenzyl trioctylphosphonium- bentonite containing poly(octadecylacrylate-co-1-vinyldodecanoate) pour point depressants on the cold flow characteristics of waxy crude oil

Wax crystals networks of paraffinic crude oil are a result of cooling processes that greatly affect the macroscopic properties of wax oil, which in turn affect the rheological behavior of waxy crude oil. Therefore, it is very important to study the effect of the formation of these crystals on the rheological properties of wax oil by considering the inhibition of the formation of these crystals. This research paper aims to study the impact of polymer nanocomposite on the pour point of paraffinic crude oil and to determine the rhetorical properties of paraffin oil treated with a polymer containing nano-layered bentonite material. Firstly, the bentonite clay (BT) was treated with a 4-vinylbenzyl trioctylphosphonium chloride monomer (VTOP) to turn the clay surface from hydrophilic to lipophilic clay (VTOP-BT) and consequently facilitate its incorporation into the octadecylacrylate-co-vinyldodecanoate copolymer.A series of the poly(octadecylacrylate-co-1-vinyldodecanoate-co-VTOP-BT) nanocomposites with different ratios of VTOP-BT (0.5–3%) was prepared using radical solution polymerization and described using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, high-resolution transmission microscopy, and proton nuclear magnetic resonance (1H NMR). The collected results from the effect of the additives on crude oil have demonstrated that polymers nanocomposites have a significant impact in reducing the viscosity of wax crude oil compared to poly(octadecylacrylate-co-vinyldodecanoate). By using a dose of 1500 ppm of poly(octadecylacrylate-co-vinyldodecanoate-co-VTOP-BT) nanocomposite that contains 1% VTOP-BT, the pour point decreased from 27 to −3 °C (i.e., 30 °C). By the same token, the long-term stability measurement, the polymer nanocomposite slowed excellent behavior compared to virgin polymer.

Quantification of crystalline wax in asphalt binders using variable-temperature Fourier-transform infrared spectroscopy

Solid crystalline wax content is an important parameter to control the quality and durability of asphalt binders produced for flexible pavement construction. Although a significant number of methods have been published for the quantification of wax in crude oil and lubricants, the direct use of these for asphalt binder characterization has faced a number of obstacles. In order to develop a precise, accurate and practical methodology for the measurement of in situ wax in binders at various temperatures, Variable-Temperature Fourier-Transform Infrared Spectroscopy (VT-FTIR) is used for the first time to determine wax contents in asphalt binders over the entire temperature domain that typical pavements experience. Cold Lake asphalt doped with varying amounts of n-alkanes, as well as a variety of commercial binders, were tested to validate the effectiveness of the VT-FTIR method. The results show that the crystalline wax contents determined by VT-FTIR are reasonably consistent with traditional cold precipitation and differential scanning calorimetry (DSC) methods. In contrast with DSC, the VT-FTIR method is able to observe the continuing increase in crystalline wax with decreasing temperature, and is able to do so over extended periods of time. On the whole, the VT-FTIR method provides a fundamental chemical analysis that probes the formation of crystalline unit cells in the asphalt binder. Hence, it is a promising approach for the accurate determination of solid crystalline wax content with the ultimate aim of controlling wax-associated pavement distresses such as raveling, cracking and moisture damage.

Numerical simulation and analysis of phase change heat transfer in crude oil

Accurately obtaining the temperature distribution of the medium in the shutdown pipe-line of waxy crude-oil has important guiding significance for making maintenance plan and restart plan. The phase transition process of waxy crude-oil involves complex problems such as natural-convection heat transfer, latent heat release, and difficulty in tracing liquid-solid interface. In this paper, the concept and significance of breaking point were proposed. Taking the breaking point and the freezing point as dividing point, a new zonal partition model was established based on the influence of phase change of crude-oil wax crystal on heat transfer mode, with the corresponding governing equations being established for different regions. With the proposed model, the effects of natural-convection on heat transfer, latent heat release, location change of condensate reservoir, heat transfer mechanism, and other key issues in the process of oil phase transition were analyzed.