OPTIMIZATION OF DEMULSIFIER FORMULATION FOR SEPARATION OF WATER FROM CRUDE OIL EMULSIONS
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In this study, various water-soluble and oil-soluble demulsifiers were selected for separation of water from crude oil emulsions and their productivity measured using the Bottle-test method at 70 °C and 10 ppm concentration. The best ones among 23 demulsifiers examined through the screening process were fatty alcohol ethoxylate, triethanol amine and urea from the water-soluble group and Basororol E2032, Basorol PDB 9935 and TOMAC from the oil-soluble category. Furthermore, the present study investigated the factors effective for demulsification such as temperature, concentration, pH, salinity and modifiers. It was found that the separation improves with increasing demulsifier concentration, increasing salt content, increasing temperature up to 80 °C, keeping the pH values between 5-9. Adding solvent modifiers proved unnecessary. Two formulations were prepared based on suggested optimal concentrations of demulsifier content by experimental design using Qualitec 4 and these proved to be highly effective in treating real and synthetic emulsions.Keywords:
Demulsifier
Crude oil is always produced with water. This association causes many problems during oil production, arising from the formation of emulsion. To overcome this issue, a synthetic surfactant, aka demulsifiers, is formulated to break the emulsion. Emulsion, a mixture of liquids with no mutual solubility between them is usually present as droplets of one liquid distributed in other continuous phase. Demulsifiers acts as an emulsion breaker, where they are able to separate the water-oil emulsions to their respective phases. There are many types of demulsifiers formulation where they may be divided into four main type of group for the oil and gas industries. This include; polymer, amines, alcohol and polyhydric alcohol. Demulsifier main function is to reduce the interfacial tension properties of the emulsion. This in turn helps break the emulsion into their respective phases. Demulsification formulation is also dictated by the properties of the crude oil. Demulsification formulation is tailor made for individual type of crude. Therefore, choosing the right demulsifiers formulation is important to give an effective separation of emulsion in crude oil processing. The objective of this review is to examine the different groups of demulsifiers used as surfactant for the removal/breakdown of emulsion from crude oil processing. Polymeric demulsifiers are found to be more suitable for water-in-oil emulsion, while the other 3 mention above are suitable for oil-in-water emulsion.
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Emulsified fuel
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Abstract A technique is described whereby the resistance of an emulsion to breaking can be quantitatively determined. Produced oilfield emulsions are usually the water-in-oil type and, accordingly, do not conduct an electrical current. However, theme is a threshold of A-C voltage pressure above which an emulsion will break and current will flow. The more stable an emulsion, the higher the required voltage. A Fann Emulsion Tester, modified so that low voltages (0 to 10 v) can be accurately measured, is suitable. This technique has application in evaluating the effect of a demulsifier on the stability of an emulsion. Emulsions can, in essence, be titrated with demulsifiers by adding a quantity of demulsifier, stirring, and measuring the voltage required to cause current to flow. Any synergistic effect of two or more materials added simultaneously can be followed accurately. A demulsifier that significantly lowers the threshold voltage (from 100 to 400 v to 0 to 10 v for the emulsions in this study) is effective and can cause the emulsion to break. A demulsifier that will bring about this drop in the threshold voltage at low concentration is very desirable. The technique is also well adapted for rapidly screening demulsifiers. Introduction Stable emulsions in produced reservoir fluids resulting from certain well stimulation and completion procedures are common problems. The use of suitable demulsifiers can often mitigate these difficulties. At the present time, a rapid and efficient method for selecting satisfactory demulsifiers is not available. It is badly needed. Reliance is now placed primarily on trial-and-error procedures. A new test method has been developed which permits a more rapid and precise selection of demulsifiers. It involves measuring the electrical stability potential* of an emulsion before and after a demulsifier has been added. This paper describes this method and shows where it should have application in field emulsion problems. NATURE OF OILFIELD EMULSIONS Two immiscible components must be present for an emulsion to form; we are concerned here with crude oil and water. An emulsifier must be present for an emulsion to be stable. Emulsifiers can be substances which are soluble in oil and/or water and which lower interfacial tension. They can be colloidal solids such as bentonite, carbon, graphite, or asphalt which collect at the interface and are preferentially wet by one of these phases. Unrefined crude oils can contain both types of emulsifiers. A popular theory is that, of the two phases in an emulsion, the dispersed phase will be the one contributing most to the interfacial tension. Usually this phase contains the least amount of emulsifier. The stability of a water-in-oil emulsion is affected by the following: viscosity; particle or droplet size; interfacial tension between the phases; phase-volume ratios; and the difference in density between the phases. A stable emulsion is usually characterized by high-viscosity, small droplets, low interfacial tensions, small differences in density between its phases, and slow separation of the phases. It also has low conductivity (high electrical stability potential).Water-in-oil and oil-in-water emulsions are both common; however, oil field emulsions are predominantly water-in-oil emulsions. The emulsions which commonly occur during completion and stimulation operations contain a combination of several of the following: acids, fracturing fluids (oil, water, acid), and formation water and oil. Produced emulsions usually contain formation water and oil. Emulsions form in oil wells because oil and water are mixed together at a high rate of shear in the presence of a naturally occurring or unavoidably produced emulsifier. During the completion and stimulation of productive zones, and while formation fluids are being produced, oil and water are very often commingled. These mixtures are formed into emulsions by agitation which occurs when the fluids are pumped from the surface into the matrix of the formation or produced through the formation to the surfaced restrictions to flow (such as perforations, pumps, and chokes) increase the level of agitation; tight emulsions are more likely to form under these conditions. Often an emulsified droplet is an emulsion itself is Therefore, emulsion-breaking problems can be quite complex. The complexity can be even greater if a third phase (gas) is included. Demulsifiers operate by tending to reverse the form of the emulsion. During this process, droplets of water become bigger, viscosity is lowered, color becomes darker, separation of the phases faster and electrical stability potential approaches zero. Any of these effects could be followed as a means of determining emulsion stability. However, electrical stability potential is the most reproducible and most easily measured parameter for following the stability of a water-in-oil emulsion. EXPERIMENTAL APPARATUS A water-in-oil emulsion is a poor conductor of electrical current. JPT P. 1229ˆ
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AbstrcatA simulated crude-oil is made up by using kerosene and crude oil.Emulsion's stability is (studied,a) simulated emulsion's the size and distribution of droplets were measured by the microscope , which the average droplets diameter of the stable emulsion is about 1μm , then the optimal crude-oil kerosene ratio ,the emulsified velocity ,the emulsified time and oil-water ratios are determined.A comparison of dewatering percentage from the simulated emulsion and crude-oil emulsion for the demulsifier (OX-9354 and ) OX-9351 is performed, the same tendency shows that the simulated emulsion can be used to appraise demulsifier.
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Kerosene
Dewatering
Oil droplet
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Demulsifier
Asphaltene
Oil droplet
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해상유출유의 풍화산물인 수분함유 기름 에멀젼(water-in-oil emulsion)의 생성경 향과 안정도, 그리고 생성속도를 16개 원유에 대하여 측정하였다. 해상유출유의 방제 전략적 측면에서 매우 중요한 요인인 에멀젼의 생성방해와 파괴를 위하여 사용되 는 유분산처리제와 에멀젼 파괴제의 성능을 비교하였다. 에멀젼의 생성경향은 사우디 아라비아산 원유와 이란원유, Dubai 원유, (Isthmus) 원유, 중국산 대경 원유 등이 높 게 나타났으며, 80-90%의 함수율을 보였다. 에멀젼의 안정도는 중동산 원유들이 대부 분 높았으며, 에멀젼 생성속도가 빠른 (Istymus) 원유와 대경원유 등은 오히려 불안정 한 특성을 보였다. 에멀젼의 생성경향과 안정도는 원유 중의 아스팔텐 함량과 가장 밀 접한 연관이 있었으며, 황, 바나디움 함량과도 처리제와 에멀젼 파괴제를 이용하여 에 멀젼 형성을 억제하는 능력을 시험한 결과, 국산 유처리제는 기름 용적의 0.2%, 정도 에서, 외산 유처리제와 에멀젼 파괴제는 0.1% 이하에서 방해 효과를 보였다. 에멀젼의 생성 방해효과는 에멀젼의 형성시기를 지연시키지만 함수율을 감소시키지는 못하는 것 으로 보인다. 에멀젼 파괴제인 Alcopol 0 유처리제에 비하여 강력한 파괴능력을 보였 으며, 에멀젼 용적의 0.1% 이하에서 빠르게 에멀젼 내로 침투하여 물과 기름으로 분리 할 수 있었다. 【Laboratory experiments were undertaken in mixing chamber to study the water-in-oil emulsion formation tendency, stability and formation rate of 16 crude oils. Arabian, Iran, Dubai, Isthmus and Daekyung crudes showed high emulsion formation tendency and had water contents of 80-90%. Emulsions of crude oils of middle East were very stable, while Isthmus and Daekyung sudes formed unstable emulsion. Emulsion formation tendency rate, and stability showed significant correlations with asphaltene content of crude oil. To evaluate the possibility of preventing mousse formation, inhibition ability of several dispersants and demulsifier was tested. They inhibited mousse formation at 0.1-0.2% concentrations (v/v). Emulsion inhibition by chemical treatment delayed the time of formation, but did not decrease water content. Demulsifying ability of dispersants and demulsifier was tested because biscous emulsion causes formidable problems in skimming, pumping and recovery operation. British demulsifier Alcohol 0 showed excellent emulsion breaking efficiency at 0.1% of emulsion Vol..】
Demulsifier
Asphaltene
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Crude oil is always produced with water. This causes many problems during oil
production, arising from the formation of emulsion. Emulsion is a mixture of liquids
with no mutual solubility between them. To overcome this issue, demulsifiers are
formulated to break the emulsion. Demulsifier main function is to reduce the
interfacial tension properties of the emulsion. The main objective of this study is to
formulate a suitable demulsifier for Malaysian crude oil. In order to formulate a
suitable demulsifier, it is important to determine the physical properties of the crude
oil as the demulsification formulation is dictated by the properties of the crude oil.
Two types of emulsion which r.re. the FOR errmlgjrm (rmrlp A) and natural Ptrmlsinn
(Crude B) was studied. EOR emulsion is the crude with surfactant-polymer (SP) in
the injection water. The combination of these three components are the next
generation technology designed to provide tolerance to extreme salinity and also
produces higher mobility control in the EOR crude.
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Abstract One of the common methods of reducing or eliminating the emulsion is the use of different chemical demulsifiers depending on the type of crude oil and water cut. This method is widely used in Kuwait Oil Company (KOC) at wellheads and gathering centers (GC). However, some wells have practice increases of demulsifier dosage as a result of increase in water content. Consequentiality, KOC initiated a program for optimization of chemical consumption for water/oil emulsion separation in the surface facilities at West Kuwait. As a result, of one year oil field statistical analysis of crude oil emulsion collected data. The results indicate that there are four oil wells of a different physical property could be very helpful for our study. Such properties include emulsion viscosity, size of water droplets, surface active materials, resin to asphaltene ratio (R/As), emulsion temperature. Over and above the demulsifier efficiency and dosages were evaluating using the calculated emulsion separation index (ESI) and interfacial tension measurement. As a result the oil field laboratory test indicates that the viscosity of emulsion increases to at least from 12 to17% of its original value based on dry condition. The average droplet size distribution near to (1–10) μm was highly effect on emulsion stability. Moreover the emulsion behavior was linked closely to the film form around the water droplets that are believed to result from the adsorption of high-molecular-weight polar molecules (asphaltene) and fine inorganic solids. There surface-active behavior that makes them good emulsifiers. Also it was found there are a consistent relationship between emulsion stability and relative resin to asphaltene content R/As for all four of the field samples under study. The crude oil of high emulsified water, near 30%, contains low (R/As, 0.84). However, as resins to asphaltene ratio increased the emulsion become unstable and emulsified water decrease up 9 %. This relationship could be used as the method to indicate the more likely oil field areas of strong emulsions and the suitable practical methods for treatment. Also from the well head operating conditions collected data; emulsion temperature, well head pressure, salinity of emulsified water and IFT. From the laboratory bottle test and oilfield crude oil emulsions data. The demulsifiers dosage was predicted using the proposed empirical model. In addition it could be used as a good tool for the new or the incumbent demulsifier evaluation.
Demulsifier
Asphaltene
Oil droplet
Produced water
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In present study, a naturally derived demulsifier (DEMLOCS) is formulated with extract of Cocos nucifera which acts as a potential bio-degradable and environment-friendly demulsifier. The emulsion sample was treated with 500–2000 ppm dosage of DEMLOCS at varying temperature range from 30 °C to 45 °C. The sample is subjected to a static bottle test to find out efficacy of demulsifier to separate oil and water. 88% of water was separated from emulsion at 2000 ppm demulsifier concentration after 24 h at 45 °C. With increase in demulsifier concentration from 500 to 2000 ppm, interfacial tension was decreased from 12.59 to 2.64 dyne/cm which ultimately increase water separation. With increase in salinity separation increases upto certain concentration of salt, afterward separation decreased. Addition of DEMLOCS reduced viscosity of emulsion substantially. After addition of 2000 ppm demulsifier at 30 °C, viscosity of the emulsion reduced by 64% which is same when temperature of emulsion increased from 30 °C to 45 °C. So, addition of demulsifier is an alternative of heating to reduce viscosities which facilitate the extent of water separation. The bio-degradability studies of prepared DEMLOCS measured by free CO2 emission confirm that prepared demulsifier is easily degradable and not to harmful either for refining system or environment.
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Refining (metallurgy)
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The formation of water-in-crude oil emulsion creates many problems in petroleum industry such as decreasing the oil recovery efficiency, high pumping cost, and piping corrosion, which needs to be treated. This formation of emulsion has been identified to be stabilised by natural surfactants consisted of carboxylic acids, phenols, asphaltenes, resins, and waxes. Several techniques have been used to destabilise the emulsion such as by using demulsifiers. However, so far, the selection of a demulsifier has been based on the trial and error method, which is very tedious. In order to develop the demulsifier selection method, a comprehensive knowledge of crude oil emulsion stability and how the demulsifier destabilises the crude oil emulsion is crucial, which needs to be studied. Therefore, this study is aimed to address this fundamental aspect by analysing the stability of six different crude oil samples, carrying out chemical demulsification study to develop a method for characterising and selecting the demulsifiers systematically, and determining the rate and mechanism of demulsification process. The stability study was carried out by analysing the water concentration and hold-up profiles, and the sedimentingcoalescing interface behaviour. It was found that there exists a correlation between the chemical properties of the crude oil such as resin-asphaltene ratio, asphaltene and solid contents, with emulsion formation and stability. A chemical demulsification experiment of crude oil emulsion was carried out using a wide range of demulsifiers used as a single demulsifiers. The demulsifier characteristics and demulsifier performance indicators were used as indicators for demulsifier selection. The results show that several indicators such as functional group, HLB number, demulsifier solubility, demulsifier effectiveness, partition coefficient, interfacial pressure, and interfacial activity have a significant correlation to the percentage of water and oil separations, which can be used to develop a method for screening the demulsifiers. By developing a mathematical model, both flocculation and coalescence rate constants, and the rate constant ratios (ano/K) can be predicted to determine the mechanism of emulsion breaking. It was found that higher (>7) and lower (<1) of the rate constant ratios demonstrate that the rate controlling step is determined by the coalescence and flocculation process respectively. While the rate constant ratios between 1 and 7 the rate controlling step is determined by both processes. The model validation by experimental data for various systems shows that the proposed model is applicable for both crude and synthetic oil emulsions. In order to obtain deeper understanding several recommendations such the effect of high pressure and temperature on emulsion formation and stability, the effect of composite demulsifiers on demulsification performance, and the thermodynamic modeling of chemical demulsification process are suggested for further studies.
Demulsifier
Asphaltene
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The current practice for crude oil demulsifier selection consists of pre-screening of the best performing demulsifiers followed by field trials to determine the optimum demulsifier dosage. The method of choice for demulsifier ranking is the bottle test. As there is no standard bottle test method, there are different methodologies reported in the literature. In this work, a new approach to bottle test and field trial was described which improved significantly the selection and dosage of the demulsifier. The bottle test was optimized by measuring an accurate mass of demulsifier. This method produces repeatable results. This bottle-test methodology was benchmarked against field trial results performed in oil processing plants. The field trials were also improved to avoid the accumulation effect of demulsifier, when optimizing their dosage. The field data for the optimization of demulsifier dosage was analyzed mathematically; and a graphical method to determine the optimum range is described.
Demulsifier
Plastic bottle
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