Water In Crude Oil Emulsions Research Articles

Chemically induced demulsification of water in crude oil emulsion from East Kalimantan oil fields

The application of demulsifiers on dewatering of crude oil emulsions from East Kalimantan oil fields is reported in this work. Two types of experiment were conducted: the bottle test in which emulsion resolution was carried out after demulsification process within the time intervals of 0, 5, 10, 15, 20, 25, 30, 40, 50, 60, 120 and 180 min at temperature of 40 °C followed by the appearance of separated aqueous layer, and identification of variety of fractions or compounds in crude oils that promote and stabilize these emulsions. Demulsification was successfully obtained by adding PT Pertamina (Persero)’s commercial demulsifier series of Pertadem B-02 and Pertadem B-06. Pertadem B-02 is the best candidate for destabilizing water in oil emulsions. The optimal percentage demulsification efficiency (DE) achieved by Pertadem B-02 was 100% with just concentration of 18 ppm for field A and 97% for field B. Moreover, demulsification activities in the water in oil emulsions by Pertadem B-02 were faster compared to Pertadem B-06. Fractions identifications showed emulsifying agents in crude oil of Field A that promote very unstable emulsions compared to crude oil of Field B from East Kalimantan.

Synthesis and Application of New Amphiphilic Asphaltene Ionic Liquid Polymers to Demulsify Arabic Heavy Petroleum Crude Oil Emulsions.

Asphaltenes are heavy petroleum crude oil components which limit the production of petroleum crude oil due to their aggregation and their stabilization for all petroleum crude oil water emulsions. The present study aimed to modify the chemical structures of isolated asphaltenes by converting them into amphiphilic polymers containing ionic liquid moieties (PILs) to demulsify the emulsion and replace the asphaltene layers surrounding the oil or water droplets in petroleum crude oil emulsions. The literature survey indicated that no modification occurred to produce the PILs from the asphaltenes. In this respect, the asphaltenes were modified via oxidation of the lower aliphatic chain through carboxylation followed by conversion to asphaltene acid chloride that reacted with ethoxylated N-alkyl pyridinium derivatives. Moreover, the carboxylation of asphaltenes was carried out through the Diels–Alder reaction with maleic anhydride that was linked with ethoxylated N-alkyl pyridinium derivatives to produce amphiphilic asphaltene PILs. The produced PILs from asphaltenes acid chloride and maleic anhydride were designated as AIL and AIL-2. The chemical structure and thermal stability of the polymeric asphaltene ionic liquids were evaluated. The modified structure of asphaltenes AIL and AIL-2 exhibited different thermal characteristics involving glass transition temperatures (Tg) at −68 °C and −45 °C, respectively. The new asphaltenes ionic liquids were adsorbed at the asphaltenes surfaces to demulsify the heavy petroleum crude emulsions. The demulsification data indicated that the mixing of AIL and AIL-2 100 at different ratios with ethoxylated N-alkyl pyridinium were demulsified with 100% of the water from different compositions of O:W emulsions 50:50, 90:10, and 10:90. The demulsification times for the 50:50, 90:10, and 10:90 O:W emulsions were 120, 120, and 60 min, respectively. The interaction of the PILs with asphaltene and mechanism of demulsification was also investigated.

Experimental investigation and mathematical modeling of oil/water emulsion separation effectiveness containing alkali-surfactant-polymer

Alkalis, surfactants and/or polymers are usually injected in the injector wells so that the injection fluids can sweep through the reservoir and mobilize/recover more oil. However, the formation of stable emulsion due to the residual chemicals in the recovered crude oil poses problems in the primary separation process. This study focuses on the effect of Alkali-Surfactant-Polymer injection on creaming and coalescence of crude oil and water emulsion produced in the primary gravity separator. In addition, a model is developed in this work to predict the separation effectiveness of oil and water emulsion containing ASP. In this work, the effect of ASP on the stability and the separation of crude oil water emulsion is investigated using the Turbiscan light transmission and back scattering device. The range of concentration of ASP used in this work is same as that found in the primary gravity separator. The investigation revealed that ASP plays an important role in the stability of the emulsion. A new model based on Stokes law and incorporating coalescence phenomena for the prediction of separation profile of oil and water in terms of separated layer profile is developed. The model is validated with experimental data obtained from the Turbiscan light transmission and backscattering device. The model is able to predict the separation profile of an oil-water emulsion containing ASP with excellent agreement.

Adsorption of crude oil from crude oil–water emulsion by mesoporous hafnium oxide ceramics

An environmentally benign, mechanically stable, and renewable mesoporous hafnium oxide ceramic synthesized via a sol–gel process has exhibited 99.9% removal capacity of crude oil from an oil-in-water emulsion.

Optimization of chemical demulsifications of water in crude oil emulsions

The instability of the water in crude oil emulsion and separation of the dispersed water as free water are influenced by the emulsion properties and the operating parameters during the demulsification process. This study aims to relate these properties/operating parameters to the amount of separated water. Steps were taken to determine and validate the optimal separations that can be achieved. Six operating parameters were identified through sensitivity analyses to have an energetic effect on percentage water separation. The bottle test method was used on two different samples of water in oil synthetic emulsions (sample A and B from different Nigerian oil fields). Response surface methodology central composite design (RSMCCD) was used to design the experiment, and generate the desired regression equations/models. Results show that optimum percentage water separations of 93 and 95% (V/V) were achieved with the emulsions A and B respectively using the combination of the optimal variables derived from the model equations. These were improvements from percentage water separations of 80 and 83% (V/V) achieved using the two crude oil samples in their naturally occurring state when the properties of the emulsions were not enhanced to their determined optimal operating conditions.

Molecular level separation of crude oil/water emulsion on carbon nanotube surface induced by weak interaction: a molecular dynamic simulation study

Huge π-conjugated system of carbon nanotubes (CNTs) endows the two-dimensional carbon-based nanomaterials with special affinity towards aromatic organic compounds such as asphaltenes. Based on the special bonding structure, functional CNTs was designed and used for demulsification of crude oil/water emulsion and the treatment of emulsified oily wastewater in our previous study. Despite the macro bottle tests and micro-scale polarizing microscope were used to observe the separation process, the nanoscale or molecular scale demulsification mechanism was still not well understood. Therefore, molecular dynamics (MD) simulations were carried out to study the adsorption and separation behaviors of crude oil/water emulsion on the CNT surface. It was interesting to found that the oil and water was gradiently separated on the CNT surface due to their different spreading velocity resulted from the different affinity and interaction energy between various molecules (water, heptane and asphaltenes) and the CNT material. The demulsification mechanism of CNT was put forward as follows: when oil droplets approach the CNT surface, the water molecules rapidly spread and flow over the CNT surface, while the saturates slowly spread along CNT surface and the molecules with π-conjugated system (such as asphaltenes) were restricted due to their strong interaction with the CNT material. Because of their enormous difference of spreading velocity and time on CNT surface, the oil molecules were stayed and accumulated on CNT surface and thereby separated from the water molecules. The results obtained in this work provides a deep insight into the oil-water separation behaviors when using carbon-based nanomaterials to demulsify the crude oil-water emulsion and the treatment emulsified oily wastewater.

Pore-scale investigation of Al2O3 nanoparticles for improving smart water injection: effect of ion type, ion and nanoparticle concentration, and temperature

The central question in this paper asks the synergistic effects of combining Al2O3 nanoparticles (NPs) and smart water at elevated temperatures for enhanced oil recovery (EOR) purposes. For this, different concentrations of NPs were added to the synthetic smart waters and evaluated through visual stability analysis by the addition of two acids (HCl and C2H4O2) and two bases (NH3 and NaOH). They were analyzed by interfacial tension (IFT) measurements at high temperatures. The optimum IFTs were investigated through contact angle, interfacial rheology, and asphaltene adsorption measurements. They were then monitored by absorbance spectroscopy for more stability analysis and injected into a three-layer porous medium for pore-scale crude oil displacement evaluation at high temperatures. PH adjustment results showed an improved nano-smart water stability by HCl at pH < pHIEP. IFT results revealed that oil/water IFT was almost halved by the addition of Al2O3 NPs and ions. Furthermore, in comparison with increasing active ions (Mg2+ and ), reducing inactive ions (Na+ and Cl−) was found to be of greater importance in IFT reduction. A new mechanism for IFT reduction by NPs was also presented based on the interfacial viscosity measurements and asphaltene adsorption analysis. The optimum IFTs also indicated an improved wettability alteration, which was attributed to the expansion of the electrical double layer by potential determining ions (Mg2+) and applied disjoining pressure by Al2O3 NPs. The injection of optimums into the transparent porous medium indicated the highest crude oil recovery of 40% in the secondary injection mode and an incremental crude oil recovery factor of 10% in the tertiary mode. Regarding the water in crude oil emulsions observed during floodings, it was concluded that increasing the number of active ions is of greater significance in emulsification as compared to reducing the inactive ions.

Water-in-oil emulsions separation using an ultrasonic standing wave coalescence chamber

The offshore extraction of crude oil produces stable water in oil emulsion. To separate this emulsion into oil and water phases, the oil/water interfacial film is commonly destroyed by the addition of chemical demulsifiers. The use of an ultrasonic standing wave force field could be an alternative to reduce the dosage of chemical demulsifiers in the coalescence process. In this work, an ultrasonic separator of water in crude oil emulsions is investigated through the use of a high frequency ultrasonic standing wave coalescence chamber. The coalescing chamber uses the acoustic radiation force to induce the coalescence of water droplets at the pressure nodes of a standing wave field. Due to temperature fluctuations, the excitation frequency is controlled to maintain the resonance in the coalescence chamber and the voltage amplitude is controlled to deliver a given acoustic power. Experimental tests using standardized emulsions of water in oil were carried out in a laboratory processing plant. The effects of ultrasound application, flow rate, initial water content, demulsifier dosage and chamber inlet temperature were analyzed. The results show that the use of the acoustic radiation force improves the emulsion separation in all the conditions analyzed, when compared with the gravitational separation technique.

Demulsification of Crude Oil in Water (O/W) Emulsions using Graphene Oxide

Implementation of nanotechnology in oil and gas industries, particularly for enhanced oil recovery (EOR) has recently gained interest. In this work, graphene oxide (GO) has been synthesized and used as nano-demulsifier for crude oil in water (O/W) emulsions. GO was synthesized by using modified Hummers’ method and characterized using X-Ray diffractometer (XRD) and Fourier Transform Infrared (FTIR) spectroscopy. Subsequently, the nano-demulsifier’s performances were tested to Field D crude oil-water emulsions by varying nano-demulsifier concentrations and contact time. The performances of GO for demulsication of crude oil-in-water emulsions were then determined by measuring the oil contents in water using a UV–Vis spectrophotometer. Demulsification tests indicated that the optimum GO concentration was around 20-40 ppm, while the optimum contact time was 30 min. The residual oil content in the separated water was as low as 100 ppm. This might be due to the amphiphilic properties of GO. It indicates that the GO is a promising demulsifier and by further understanding the intrinsic interaction between GO and crude oil, the performances of GO can be easily tailored in the future.

Study of Influences of Fracture Additives on Stability of Crude Oil Emulsion

Background: A hydraulic fracture is a key technology to increase production of the low permeability oil fields. Fracture additives such as gels, friction reducers, pH adjusters and clay stabilizers were injected into the underground. While more than 50% of the fracture fluid remains underground. The residue of fracture fluid comes out with the produced liquid (a mixture of crude oil and water) in the subsequent oil recovery process, which results in a highly stable crude oil-water emulsion. Objective: The stability and stable mechanism of the emulsion with fracture fluid have been experimentally investigated. Materials and Methods: The influences of fracture additives and components of crude oil on the stability of emulsion were investigated by bottle test and microscopic examination. The interfacial tension and modulus of dilation were explored by a spinning drop interfacial tension meter and an interface expansion rheometer, respectively. Results: The fracture additives played the key role on the emulsion stability. On one hand, the interface energy of oil-water was reduced by friction reducer (IFT was decreased from 24.0 mN/m to 1.9 mN/m), which was a favor for the formation of an emulsion. On the other hand, the dilational modulus of crude oil-water film was increased by hydroxypropyl guar and pH adjuster (Na2CO3) to form a viscoelastic film, which resulted in a highly stable emulsion. Conclusion: The residual fracture fluid accompanied by produced liquid resulted in a highly stable emulsion. The emulsion with fracture additives was difficult to be broken, which may affect the normal production of the oil field. A positive strategy such as developing demulsifier with high efficient should be put onto the schedule.

Effect of polymer concentration on the properties of the crude oil-water emulsion

In order to clarify the stability mechanism of the crude oil-water emulsion during polymer flooding, the effect of polymer concentration on the properties of the crude oil-water emulsion is systematically investigated by laboratory experiment, including the changes of the compositions of the crude oil, the parameters of interfacial tension, interfacial electrical property, interfacial expansion rheology and interfacial shear rheology, which can be used to characterize the change of the oil-water interfacial properties under the different polymer concentration. The results show that polymer molecules can be absorbed at oil-water interface to react with the asphaltene and resin to reduce the interfacial energy, increase the modulus of interfacial expansion rheology and interfacial shear rheology, and enhance the electronegativity of the oil-water film, which is contributed to emulsification, so that the emulsion is more stable with the increase of the polymer concentration.

Comparative Study on Surfactants Mixtures in Aqueous Solution at Atmospheric Pressure and 10 bar Reservoir Atmosphere

This paper considers anionic and nonionic surfactants, as candidates for crude oil production by enhancement applications. In this study some colloidal properties of surfactants were tested by conventional and new test methods. The oil in water type emulsions have great importance in the petroleum industry. The stability of crude oil in water emulsions are investigated in a wide range of physical and chemical circumstances. Investigations at 10 bar are needed to get knowledges on the real conditions of the given petroleum exploration processes. A special glass cell was used for the tests of the mixtures various crude oil-water emulsions under hydrocarbon gas atmosphere and for the oil disclapement efficiency. Based on the experimental results it was found that emulsifying capacity was changed significantly by the real process conditions. The decrease of the density of hydrocarbon phase was contributed to the overall reduction in the efficiency of emulsifiers also occurred. Based on the experimented data it is supported to pay more attention to apply the real test conditions or approximate the real values.

Ecofriendly demulsification of water in oil emulsions by an efficient biodemulsifier producing bacterium isolated from oil contaminated environment.

Water in oil emulsions increase oil processing costs and cause damage to refinery equipment which necessitates demulsification. Since chemical demulsifiers cause environmental pollution, biodemulsifiers have been paid more attention. This study aims to identify biodemulsifier-producing bacteria from petroleum contaminated environments. As a result, several biodemulsifier producing strains were found that Stenotrophomonas sp. strain HS7 (accession number: MF445088) which produced a cell associated biodemulsifier showed the highest demulsifying ratio, 98.57% for water in kerosene and 66.28% for water in crude oil emulsion after 48h. 35°C, pH 7, 48h incubation and ammonium nitrate as nitrogen source were optimum conditions for biodemulsifier production. Furthermore, it was found that hydrophobic carbon sources like as liquid paraffin is not preferred as the sole carbon source while a combination of various carbon sources including liquid paraffin will increase demulsification efficiency of the biodemulsifier. The appropriate potential of this biodemulsifier strengthens the possibility of its application in industries especially petroleum industry.

Demulsification of water in crude oil emulsion using long chain imidazolium ionic liquids and optimization of parameters

In this work, the application of ionic liquids in separation of water from crude oil as a water demulsifier was reported. Imidazolium ionic liquids substituted with long alkyl chains (n = 10, 12 and 14) were synthesized and used as surface-active demulsifiers which were coupled with Cl, PF6 and NTf2 anions. A full factorial design was performed for optimizing the behavior of demulsifiers based on three factors, i.e. alkyl chain length of cation, anion type and IL dosage in three levels. The measurements of interfacial tension between crude oil and water were done for each run and, the bottle test was carried out after demulsification process within the time intervals of 1, 2, 6 and 24 h. The optimal results for water separation efficiency and interfacial tension (IFT) were obtained 86–95% and 0.7–6.26 mN/m, respectively. The IFT reduction results showed that the studied ILs can be good candidates in enhanced oil recovery. It was found that increasing the ionic liquid hydrophobicity could significantly improve the demulsification efficiency along with IFT reduction. In hydrophobic ILs, it was indicated that increasing the alkyl chain length might improve the results, thus [C14mim][NTf2] showed the best results in the bottle test as well as IFT reduction to 0.8 mN/m with 2000 ppm. The changes in droplet size were monitored by optical microscopy.

Synthesis and Application of Poly(ionic liquid) Based on Cardanol as Demulsifier for Heavy Crude Oil Water Emulsions

Amphiphilic poly(ionic liquids), PILs, derived from natural products attracted great attention as a green chemical in the field of the surface chemistry and petroleum industry. In the present work, new surface active PILs were synthesized from cardanol cashew nut oil as a hydrophobic alkyl phenol. The phenol group was etherified with diethanolamine, ethanolamine, and tetraethylene glycol using linking agent based on β,β-dicholorodiethyl ether to insert nonionic hydrophilic groups into cardanol. The amine group was quaternized with 2-acrylamido-2-methyl-1-propanesulfonic acid to produce polymerizable ionic liquids that polymerized to obtain new PILs. The chemical structure of the prepared new PILs was elucidated from 1HNMR and elemental analysis. The surface activity of the prepared PILs was determined from the surface and interfacial tension measurements of their aqueous solution. The ability of the prepared PILs to disperse the asphaltene fractions of the heavy Arabian crude oil was studied. It was used ...

Optimum demulsifier formulations for Nigerian crude oil-water emulsions

The formation of crude emulsion during oil production and processing is a challenge of significant proportions to the oil producers. Studies show that about two third of Nigerian crude oil production is in form of water in oil emulsion. For economic and operational reasons, it is necessary to separate the water completely from the crude oil before transportation or refining.Efficiency of separation of crude emulsions is of major importance to producers. To this end, this study primarily seeks to investigate the formulation of effective demulsifier that can be used to achieve this aim; and in so doing, the optimal separation efficiency attainable by this demulsification process is determined. Six different samples of water and oil soluble demulsifiers were used on two different samples of synthetic emulsion (sample I and II (both water in oil emulsion) from different Nigerian oil fields). The bottle test method was used to determine the percentage water separation for each crude oil emulsion/chemicals (demulsifiers) mixture. The concentrations of the combined six chemicals (demulsifier samples A–F) in the mixture were related to the percentage water separation using response surface methodology central composite design (RSMCCD).Results show that the optimum concentrations of demulsifiers A–F are 59 ppm/39 ppm/29 ppm/20 ppm/29 ppm/13 ppm respectively for crude oil sample I. While 54 ppm/40 ppm/25 ppm/21 ppm/29 ppm/8 ppm respectively were observed as optimum concentration for crude oil II. The combination of these chemical was observed to return better performance than the existing commercial demulsifiers with percentage water separation of 92% and 94% compared to percentage water separation of 87% and 90% returned by one of the currently available demulsifier used in the petroleum industry for crude oil A and B respectively. Hence, the need to carry out optimization analyses on different emulsified crude oil cannot be over-emphasize.

Gravity induced coalescence in emulsions with high volume fractions of dispersed phase in the presence of surfactants

We report studies on the effect of volume fraction and surfactant concentration on the kinetics of destabilization of emulsions under the influence of gravity. Model oil‐in‐water emulsions, designed to mimic crude oil–water emulsions, were prepared with varying volume fractions of dispersed oil but nearly identical normalized initial drop size distributions. The gravity separation process was observed by periodically withdrawing samples, and examining the droplet size distribution under the microscope. Experiments were performed for three volume fractions of dispersed phase and two surfactant concentrations (0.4 and 1.6% by weight). At higher oil fractions (20%) and a lower surfactant concentration (0.4%), it was observed that although the rate of coalescence increased, the actual oil separation was delayed. At higher surfactant concentrations (1.6%), the dominant factor in suppressing destabilization is the rate of drop to interface coalescence. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4379–4389, 2017

The Role of Shearing Energy and Interfacial Gibbs Free Energy in the Emulsification Mechanism of Waxy Crude Oil

Crude oil is generally produced with water, and the water cut produced by oil wells is increasingly common over their lifetime, so it is inevitable to create emulsions during oil production. However, the formation of emulsions presents a costly problem in surface process particularly, both in terms of transportation energy consumption and separation efficiency. To deal with the production and operational problems which are related to crude oil emulsions, especially to ensure the separation and transportation of crude oil-water systems, it is necessary to better understand the emulsification mechanism of crude oil under different conditions from the aspects of bulk and interfacial properties. The concept of shearing energy was introduced in this study to reveal the driving force for emulsification. The relationship between shearing stress in the flow field and interfacial tension (IFT) was established, and the correlation between shearing energy and interfacial Gibbs free energy was developed. The potential of the developed correlation model was validated using the experimental and field data on emulsification behavior. It was also shown how droplet deformation could be predicted from a random deformation degree and orientation angle. The results indicated that shearing energy as the energy produced by shearing stress working in the flow field is the driving force activating the emulsification behavior. The deformation degree and orientation angle of dispersed phase droplet are associated with the interfacial properties, rheological properties and the experienced turbulence degree. The correlation between shearing stress and IFT can be quantified if droplet deformation degree vs. droplet orientation angle data is available. When the water cut is close to the inversion point of waxy crude oil emulsion, the interfacial Gibbs free energy change decreased and the shearing energy increased. This feature is also presented in the special regions where the suddenly changed flow field can be formed. Hence, the shearing energy is an effective form that can show the contribution of kinetic energy for the oil-water mixtures to interfacial Gibbs free energy in emulsification process, and the emulsification mechanism of waxy crude oil-water emulsions was further explained from the theoretical level.

Effects of crude oil-water emulsions at various water-cut on the performance of the centrifugal pump

The viscosity of the oil-in-water or water-in-oil depends on the water-cut (WC) present in the system. At a certain WC, the water-crude oil emulsion gives the highest viscosity, showing phase inversion, at which the performance of a centrifugal pump drops. In this article, experimental and analytical investigations have been carried out to study the performance of a centrifugal pump for the crude oil-water emulsion systems prepared by mixing crude oil obtained from an Indian oil field and water. The viscosities of the emulsions having different WC were recorded and a phase inversion point within 60%-70% WC range was obtained. During testing of the pump, emulsion samples were collected and stability of the emulsions was determined. A performance study on the centrifugal pump has been carried out using various samples of the emulsions. The study shows that the increasing WC reduces the pump performance till the phase inversion point. It has been observed that the quality crude oil and the emulsion affect the performance of the centrifugal pump. [Received: February, 15 2016; Accepted: March 28, 2016]

Effects of crude oil-water emulsions at various water-cut on the performance of the centrifugal pump

The viscosity of the oil-in-water or water-in-oil depends on the water-cut (WC) present in the system. At a certain WC, the water-crude oil emulsion gives the highest viscosity, showing phase inversion, at which the performance of a centrifugal pump drops. In this article, experimental and analytical investigations have been carried out to study the performance of a centrifugal pump for the crude oil-water emulsion systems prepared by mixing crude oil obtained from an Indian oil field and water. The viscosities of the emulsions having different WC were recorded and a phase inversion point within 60%-70% WC range was obtained. During testing of the pump, emulsion samples were collected and stability of the emulsions was determined. A performance study on the centrifugal pump has been carried out using various samples of the emulsions. The study shows that the increasing WC reduces the pump performance till the phase inversion point. It has been observed that the quality crude oil and the emulsion affect the performance of the centrifugal pump. [Received: February, 15 2016; Accepted: March 28, 2016]