Crude Oil Demulsification Research Articles

Research and Application Progress of Crude Oil Demulsification Technology

The extraction and collection of crude oil will result in the formation of numerous complex emulsions, which will not only decrease crude oil production, raise the cost of extraction and storage, and worsen pipeline equipment loss, but also seriously pollute the environment because the oil in the emulsion can fill soil pores, lower the soil’s permeability to air and water, and create an oil film on the water’s surface to prevent air–water contact. At present, a variety of demulsification technologies have been developed, such as physical, chemical, biological and other new emulsion breaking techniques, but due to the large content of colloid and asphaltene in many crude oils, resulting in the increased stability of their emulsions and oil–water interfacial tension, interfacial film, interfacial charge, crude oil viscosity, dispersion, and natural surfactants have an impact on the stability of crude oil emulsions. Therefore, the development of efficient, widely applicable, and environmentally friendly demulsification technologies for crude oil emulsions remains an important research direction in the field of crude oil development and application. This paper will start from the formation, classification and hazards of crude oil emulsion, and comprehensively summarize the development and application of demulsification technologies of crude oil emulsion. The demulsification mechanism of crude oil emulsion is further analyzed, and the problems of crude oil demulsification are pointed out, so as to provide a theoretical basis and technical support for the development and application of crude oil demulsification technology in the future.

Analytical evaluation of oil and water obtained from demulsification of crude oil using cashew (<i>Anacardium occidentale</i>) nutshell liquid

The physiochemical characteristics of oil and water obtained from the demusifier treatment of crude oil using equal concentrations of Cashew nutshell liquid (CSNL) and a commercial grade demulsifier (DX077) were evaluated. Results obtained shows that basic sediment and water (BSW) of the crude after treatment with CSNL and DXO77 were 17.5 and 17.9 % respectively which was 0.4% apart. The total oil and grease (TOG) and total petroleum hydrocarbon (TPH) of the produced water after treatment with CSNL were 24.4 and 21.7 mg/l respectively while results after treatment with DXO77 were 23.7 and 20.5 mg/l respectively. The TOG and TPH of the produced water after demulsifier treatment with CSNL and DX077 were within acceptable limit of < 30.0 mg/l as specified by Department of Petroleum Resources (DPR). Analyses of the same crude oil before demulsifier treatment gave a lower BSW of 9.50 % as well as an emulsion band of 16.2 % indicating improper oil/water separation. The TOG and TPH of the produced water before demulsifier treatment were 42.5 and 38.7 mg/l respectively which were above DPR specification. Disposal of produced water with high TOG and TPH into the environment can lead to the release of volatile organic compounds (VOCs) into the ecosystem resulting in environmental pollution as well as other health hazards. Results obtained also show that the water density, pH, electrical conductivity, salinity and chloride of the produced water after demulsifier treatment with CSNL and DX077 were within DPR specification. Reinjecting produced water with high salinity, chloride and conductivity into the reservoir can reduce oil recovery especially from sandstone and carbonate reservoirs. CSNL proved to be an effective demulsifier and is preferrable to the synthetic demulsifier (DX077) because it is more environmentally friendly owing to its green nature.

Novel insights into the effects of asphaltenes on oil phase properties: Crude oil, oil-water interface, and graphene oxide synergistic demulsification

In this work, quantum chemical calculations and molecular dynamics simulations were employed to investigate the aggregation structure of asphaltene (a key component in heavy oil) and the influence of its molecular structure and content on the viscosity of heavy oil. Research suggests that the C5Pe molecules have a strong potential to bind together through π-π interactions (face-to-face). The angle between the two plane normal vectors was 1.4°. The mechanism of asphaltene-oil phase assembly can be succinctly summarized as the “rebar-cement” mode of action. The viscosity of heavy oil increases with the increase of asphaltenes, which can be attributed to the more complete construction of the three-dimensional network structure of asphaltene with the increase of asphaltene mass fraction (especially exceeding 35 wt%). The steered molecular dynamics simulation confirmed that reducing the concentration of asphaltenes in emulsified heavy oil droplets leads to increased susceptibility to mechanical destruction. This observation implies that asphaltenes negatively impact the demulsification and viscosity reduction of crude oil. The findings in this work can contribute to the development of efficient strategies for viscosity control and enhanced production of heavy oil resources.

Application of Novel Biodegradable Demulsifier Synthesized from Helianthus annuus in Field Crude Oil Demulsification─Experimental and Modeling Approach through RSM

Application of Novel Biodegradable Demulsifier Synthesized from <i>Helianthus annuus</i> in Field Crude Oil Demulsification─Experimental and Modeling Approach through RSM

Structure effect in the demulsification performance of cationic surfactants

In this study, various cationic surfactants and MgO nanoparticles were used for dehydration of crude oil. The results of bottle tests exhibited that in demulsification of crude oil in the serious of alkyl trimethyl ammonium bromide homologs (CnTAB, n = 12, 14, and 16) with the increase of alkyl chain length, the optimum concentration level decreased and speed of dehydration decreased. Also, for surveying the role of head group, two cetrimonium bromide and cetylpyridinium bromide surfactants were used. Evaluation of the counter ion effect indicated in the high concentration of surfactants the counter ion can greatly influence the demulsification performance. Moreover, for enhancing demulsification, MgO nanoparticles were mixed with cetrimonium bromide (CTAB) surfactant. The mixture of MgO nanoparticles and CTAB (in ratio 1:3) could dehydrate crude oil in 300s. For better understanding of asphaltene-demulsifier interaction, was used the quantum calculation. The results demonstrate MgO interacts with asphaltene strongly.As well as the result of asphaltene adsorption on MgO indicate the asphaltene adsorption flow from Freundlich model. Finally, the interaction energy between surfactants or MgO and asphaltene were estimated by quantum calculation.

Synthesis of Hyperbranched Polymers and Prospects for Application in Oilfield Chemistry

Hyperbranched polymer is a kind of polymer with a three-dimensional structure, which contains a highly branched structure and a large number of modified terminal functional groups. The desired properties can be obtained by modifying the active end groups appropriately. Hyperbranched polymers have been successfully used in the development of oilfield chemicals due to their excellent properties of solubility, rheology, temperature resistance, and salt resistance. Therefore, the application of hyperbranched polymer is helpful to the efficient development of oilfields. In this paper, the synthesis methods of hyperbranched polymers are reviewed. The advantages and disadvantages of different synthesis methods are analyzed. Furthermore, the research progress of hyperbranched polymers in oilfield chemistry is systematically described, and the advantages and existing problems of their application in polymer flooding as oil displacement agents, demulsification of crude oil, clay hydration expansion inhibition, and shale inhibition are discussed. Finally, the application prospect of hyperbranched polymer in drilling chemistry, oil recovery chemistry, and gathering and transportation chemistry is forecasted, which is expected to help the popularization and application of hyperbranched polymer in oilfields.

Experimental study on the performance of an electric field enhanced separator for crude oil production fluid

As most of the oil fields gradually come to the middle and late exploitation period, the crude oil production becomes more complex, stable and water cut is also very high. This has brought challenges to oil–water separation in onshore and offshore production trains especially for the demulsification and dehydration of crude oil. In particularly, the pre-separation efficiency of conventional three-phase separators installed at the front position of the crude oil processing systems are severely affected. In this paper, we explored the demulsification performance of W/O emulsion in an electric field-enhanced separator with insulated electrode assembly inside by static demulsification experiment and dynamic demulsification experiment separately. Focused beam reflectance measurement (FBRM) was used to make real-time online measurements of water droplet sizes in the emulsion. The average water droplet diameters, distribution of droplets within certain size and water content in oil outlet of the separator are set as indicators for evaluating the dehydration performance. The effect of electric voltage, frequency, water content and inlet flowrate on the demulsification performance were both investigated. Experimental results showed that the high frequency AC electric field with insulated electrode can promote the growth of small water droplets and thus contribute to the demulsification. The dehydration performance is deteriorated drastically with the increase of inlet water content or flowrate. The electrical field parameters such as electrical voltage and frequency both have obvious effect on the diameter distribution of dispersed water droplets and water contents at oil outlet of the separator. For certain inlet water content 20% and inlet flowrate 0.3 m3/h, the optimal electrical voltage is 5 kV and frequency is 3 kHz. The research results can provide guidance for the optimization and performance improvement of the electric field-enhanced separator.

Review on Application of Nanotechnology for Asphaltene Adsorption, Crude Oil Demulsification, and Produced Water Treatment

Nanotechnology is widely recognized for having important applications in many industries, one of which is oil and gas. Both environmental and cost benefits can be achieved when using nanoparticles for the separation of water and oil or further purification of produced water. More efficient emulsion separation can be achieved by selective adsorption of naturally present stabilizing components or magnetic action applied to nanoparticle-tagged droplets. The focus of this review is given to both nanoparticles and nanocomposites that have been studied with respect to asphaltene adsorption, crude oil demulsification, and produced water treatment, as well as oil spill cleanup and improvement of antifouling resistance of filtration membranes. Asphaltene chemistry and its role in emulsion stabilization are discussed in detail.

Molecular dynamics study on emulsified oil droplets with nonionic surfactants

The stability of heavy crude oil is closely related to the netlike structure formed by the aggregation of asphaltene and resin molecules inside the oil droplets, and the aggregation is too complex to accurately obtain the microstructure of these molecules experimentally. In this paper, molecular dynamics (MD) simulation was performed to investigate the structure of emulsified oil droplets on the molecular level. The simulation results showed: (i) The stacking structure of asphaltene and resin molecules form the netlike structure of the oil droplet, and it is also considered as the main reason of high stability and viscosity of heavy crude oil. (ii) When nonionic surfactants were introduced, some of them can adsorb to the surface of oil droplet and change its hydrophilicity; others can enter the interior of the oil droplets and destroy the stacking structure of asphaltene or resins inside the oil droplet. The decreased viscosity of emulsified heavy oil in the present of surfactants attributed to the increase of hydrophilicity on the oil drop surface and the damage of stacking structure inside the oil drops. (iii) the steered molecular dynamics (SMD) simulation proved that the mechanical properties of emulsified heavy oil droplet become easier to be destroyed with the increase of surfactant concentration, and it indicates that nonionic surfactant is beneficial to promote demulsification and viscosity reduction of crude oil.

Research results on the effects of magnetic fields on crude oil

The paper presents the results of the process of demulsification of crude oil, well No. 15 of the Supsa field. The reasons for the formation of persistent petroleum emulsion are considered, the component composition of crude oil is determined, including the content of the amount of formation water. The experiments were carried out at low (20-30)Hz and high (50-80) Hz frequencies of the magnetic field. The destruction of the oil-water emulsion was carried out without heat treatment under conditions of stabilization of the magnetic field and demulsifier Alkan 202. The technological scheme and parameters of crude oil dehydration are given. The influence of the magnetic field on the rate of destruction of the water-oil emulsion and the amount of released water is shown.

CO2-responsive zwitterionic copolymer for effective emulsification and facile demulsification of crude heavy oil

Viscosity reduction by emulsification would greatly facilitate the exploitation and pipelining transportation of heavy oil, as well as oil sands/sludge washing. However, the final demulsification process to achieve separation of oil and water is tricky. Therefore, developing smart emulsifiers that can be switched on demand to achieve both effective emulsification and facile demulsification in subsequent oil/water separation process would be of great significance to the practical applications. In this paper, a zwitterionic copolymer emulsifier comprising acrylamide (AM), 2-(diethylamino)ethyl methacrylate (DEAEMA) and 3-[dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]azaniumyl]propane-1-sulfonate (SBMA) was prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization for better control of the molecular weight, exhibiting good salt resistance and fast CO2-responsiveness. The prepared copolymer can efficiently emulsify heavy crude oil with a viscosity reduction rate up to 98.6% in highly mineralized water. While in the presence of CO2, the formed heavy oil/water emulsions can be rapidly broken to obtain oil-water two phases. Compared with traditional demulsification methods, the CO2-responsive strategy presented in this work can achieve a lower oil content in water (1.4%) after separation. Furthermore, the copolymer can also be applied to effectively emulsify and clean oily sludge. The CO2-responsive zwitterionic copolymer emulsifier demonstrated great potential in various engineering applications including exploitation and pipelining transportation of heavy oil, and oil sands/sludge washing, facilitating reduction of water pollution and energy saving.

An overview of recent technique and the affecting parameters in the demulsification of crude oil emulsions

The crude oil mix with water through processing and under significant shear at the wellhead and with the assistance of surface-active substance which is present naturally in the crude oil leading to the formation of water-oil emulsions. These emulsions are undesirable and cause problem like pipeline corrosion, pump malfunctions, poisoning of downstream refinery catalysts, and other problems. Emulsions are needed to demulsify and separate the water. There are various parameters related in crude oil demulsification that can both reduce or rise the stability of the emulsion by altering each. Therefore, this study presents an overview of research efforts on the state-of-the-art demulsification techniques through the last years and the parameters affecting the demulsification process. Firstly, an overview of the crude oil emulsion, kinds, formation, and stability. After that, a short discussion of the different demulsification techniques process. Finally, the study of the parameters affecting the demulsification process, including salinity, temperature, pH, water content, and emulsifier/demulsifier dose. The review of literature culminated in the proposition for future research.

Surfactant for petroleum demulsification, structure, classification, and properties. A review

Crude oil as a complex fluid often consists of colloidal particles. These colloidal particles are made up of asphaltenes and resins diffused in a blend of aliphatic and aromatic solvents. At various stages of crude oil production, there is usually an occurrence a water-in-oil emulsion. The stability of the emulsion formed is dependent on the occurrence of the interfacial barrier which prevents the coalescence of the dispersed water droplets. Several operational difficulties are often encountered during crude oil processing as a result of the presence of water. These difficulties range from corrosion in equipment and pipelines as well as an increase in the production cost. Hence, to mitigate these economic and operational challenges, it is crucial to ensure that the water is separated from the crude oil prior to transporting or refining the oil. Demulsification using surfactant is one of the effective techniques used for the separation of crude oil from water. This paper presents a short review of the various application of surfactants for demulsification, their structure, classification as well as their properties. In addition, the mechanism and techniques for demulsification of crude oil were also presented.

Applying ultrasonic fields to separate water contained in medium-gravity crude oil emulsions and determining crude oil adhesion coefficients

Separating produced water is a key part of production processing for most crude oils. It is required for quality reasons, and to avoid unnecessary transportation costs and prevent pipework corrosion rates caused by soluble salts present in the water. A complicating factor is that water is often present in crude oil in the form of emulsions. Experiments were performed to evaluate the performance of ultrasonic fields in demulsifying crude oil emulsions using novel pipe-form equipment. A horn-type piezoelectric ultrasonic transducer with a frequency of 20 kHz and power ranging from 80 W to 1000 W was used for experimental purposes. The influences of the intensity of ultrasonic fields, ultrasonic irradiation time, and the initial water content of crude oils were evaluated to establish the rate of water segregation from oil. The experiments applied ultrasonic-field intensities of 0.25 W/cm3, 0.5 W/cm3, 0.75 W/cm3 and 1 W/cm3 to synthetic emulsions with 10%, 15%, 20%, and 25% of the water in crude oil. Crude oil demulsification occurred for each ultrasonic field intensity tested for all the samples tested. Function β involving adhesion coefficients was expressed in terms of wave-field intensity and initial concentration of water in each of the three crude oil samples tested. The experiments demonstrated that despite the absence of any chemical demulsifier involved, water separation caused by applying ultrasonic fields was effective and occurred rapidly. As the intensity of the ultrasonic field applied increased, the amount of water segregated from crude oil also increased. Subjected to constant field intensity, higher initial water cuts (up to 15% or so) in the crude oil samples and higher ultrasonic irradiation times, resulted in greater segregation of water from crude oil in percentage terms. However, in samples with initial water cuts of 20+% long irradiation times (~5 min), resulted in a decline in water separation compared to 2-min tests. Ultrasonic field treatments offer commercially-viable and environmentally-friendly alternatives to treatments using chemical demulsifiers as they reduce desalination requirements of wastewater.

Demulsification of Water-Containing Crude Oil Driven by Environmentally Friendly SiO2@CS Composite Materials

Relatively low cost, environmental friendly, and high-efficiency silicon dioxide/carbon sphere composite demulsifiers (SiO2@CS) were prepared via an in situ hydrothermal–calcination route. They wer...

Demulsification of Colombian Heavy Crude Oil (W/O) Emulsions: Insights into the Instability Mechanisms, Chemical Structure, and Performance of Different Commercial Demulsifiers

Chemical products such as PEO/PPO block copolymers or alkoxylated resins tend to work well in chemical demulsification of light hydrocarbons (°API > 20) but fail to do so in the presence of heavy a...

Formulation of alternative demulsifiers with palm oil based surfactants for crude oil demulsification

Palm oil-based surfactants were used to formulate demulsifiers for crude oil demulsification as alternatives to petroleum-based surfactants. A light crude oil sample obtained from x field crude oil well contained 0.713% (w/w) asphaltene and 25.75% BS&W. The formulation of demulsifiers was carried out by the selection of a primary surfactant from Sodium Methyl Ester Sulfonate (SMES) and Diethanolamide (DEA), and the concentration of co-surfactant addition. The best formulation was SMES as a primary surfactant with the addition of a 10% DEA co-surfactant. The best solvent was the solution of toluene and xylene (1:1). The temperature treatment of 80 °C separated 100% water from crude oil emulsion and decreased BS&W to 5.45%.

Improvement in demulsification of Iraqi crude oil with water removal demulsifiers in oil fields

This study is targeted to present an overall survey on the most eminent techniques and methods that could be used in treating petroleum emulsions. Presently, the generally used way for handling petroleum emulsion is the process of chemical additives, known as demulsifers. Considered nanomaterials are materials used for boosting oil restoration. This project discusses whether the collection of demulsifiers and nanomaterials can supply a much stable emulsion than demulsifiers only to obtain the best method of removal of water phase from crude oil emulsion mixture. Previous studies carried out two sections of experiments in their search. First were performed utilizing three kinds of demulsifiers; non-ionic, ionic, and cationic demulsifier. Trade names of those demusifiers were Poly Ethylene glycol (PEG), sodium dodecyl sulphate (SDS), and cetyltrimethyl ammonium bromide (CTAB). The other section utilized groups of self-same demulsifiers referred to at the top with nanomaterials were aluminium oxide (Al2O3) (60nm). These experiments were carried out using laboratory batch of homogenizer stirrer. These two sections were investigated with effect of different parameters such as; the kind of substance and the concentration or dosage of demulsifiers, various proportion of water to oil, stirring temperature, stirring speed of mixing, various of pH, TDS, on the efficiency of water removal. The sample test of case study used Iraqi crude oil (Basra & Kirkuk Oil fields.The results reached efficiency water removal of (86%) by (SDS) at optimum operating parameters, so, it is better than other chemical demulsifiers reaching the efficiency water removal (84%) by (CTAB) and (67%) with (PEG). However, the maximum efficiency improved within the range 88-90% of water separation from oil was obtained with using a blend of SDS with non-materials of (Al2O3) at optimum values of parameters.

Research on ultrasound-assisted demulsification/dehydration for crude oil.

Crude oil demulsification and dehydration are important links in the process of crude oil exploitation, transportation, and refining. In recent years, with the development of crude oil exploitation, the content of colloid and asphaltene in crude oil has been increasing, and the properties of crude oil emulsion have become more stable. In addition, the development and application of oil recovery technology and the use of a large number of oilfield chemicals have made the composition of crude oil more complicated. The water content and salt content of oil produced fluid increase year by year, which aggravates the task of crude oil dehydration and desalination. Therefore, it is particularly important to study the demulsification and dehydration of crude oil. In this paper. Research on ultrasound-assisted demulsification/dehydration for crude oil in investigated. Results indicate that the demulsification effect varies with the increase of ultrasonic radiation time, but the difference is not significant; with the increase of temperature, the effect of ultrasonic on the demulsification of crude oil emulsion is decreased, or the advantages of ultrasonic can be fully displayed only at low temperature; ultrasonic power has a critical value, when it is lower than this critical value, ultrasonic wave acts as demulsifying agent, and with the increase of power, dehydration rate of the crude oil emulsion increases; when higher than the critical value, the separated oil and water can be re-emulsified; ultrasonic demulsification can both shorten settling time and reduce the amount of demulsifier; ultrasound is suitable for demulsification and dehydration of crude oil emulsions with high water content. Results also prove that chemical demulsifier has a better effect for crude oil demulsification /dehydration than that of ultrasonic treatment alone. In addition, recent progress on ultrasonic demulsification equipment is introduced. The purpose of this paper is to offer equipment and technical support for crude oil demulsification/ dehydration.

Addition of silica nano-particles for the enhancement of crude oil demulsification process

Different chemical demulsifiers were added to heavy Fula crude oil samples (Balila, Sudan) in screen test with and without the addition of silica nanoparticles (NPs). Two particle sizes of 25 nm and 95 nm were investigated using three different concentrations of 30 ppm, 60 ppm and 90 ppm. The addition of silica nanoparticles resulted in a clear improvement in demulsification in most cases. An increase of 150% in water separation was achieved with the addition of 25 nm silica NP suspension in a volume ratio of 1:0.5 (chemical demulsifier to silica nanoparticles) at a concentration of 60 ppm.