VISCOSITY OF WATER-IN-OIL EMULSIONS FROM DIFFERENT API

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VISCOSITY OF WATER-IN-OIL EMULSIONS FROM DIFFERENT API GRAVITY BRAZILIAN CRUDE-OILS Marcia Cristina Khalil de Oliveira, Luise R. O. Miranda, Alexandre B. M. de Carvalho, and Daniele Fraga S. Miranda Energy Fuels, Just Accepted Manuscript • DOI: 10.1021/acs.energyfuels.7b02808 • Publication Date (Web): 12 Feb 2018 Downloaded from http://pubs.acs.org on February 13, 2018

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VISCOSITY OF WATER-IN-OIL EMULSIONS FROM DIFFERENT API GRAVITY BRAZILIAN CRUDE-OILS Marcia Cristina K. de Oliveira*, Luise R. O. Miranda, Alexandre B. M. de Carvalho, Daniele Fraga S. Miranda. *[email protected] PETROBRAS/CENPES, Av. Horácio Macedo, 950, Cidade Universitária, ZIP 21941-915, Rio de Janeiro, Brazil. KEYWORDS: crude oil, viscosity, crude oil emulsions

ABSTRACT: Water-in-oil (W/O) emulsions are very common in oil field operations and are formed due to energy input from turbulence caused by the flow in the production pipelines, pumps and valves. Understanding emulsions rheological behavior is crucial to deal with flow assurance issues. This paper presents and discusses a series of rheological experiments carried out with synthetic emulsions formulated with 126 Brazilian crude oils with American Petroleum Institute (API) gravity ranging from 13 to 35°. This rheological study includes viscosity dependence on shear rate, temperature and water volume fraction. The results show that crude oils with similar API gravity and viscosity can generate emulsions with very different viscosities (8 to 50 mPa.s at 50ºC around 25ºAPI, for example) and different maximum water content limit. Besides, W/O emulsions that are prepared with either light (API > 35°) or heavy crude oils (API < 13°) are the ones observed to be the more difficult to stabilize: particularly the high water cut ones. Also, a large amount of data show that intermediate API gravity crude oils can incorporate up to 70% water volume fraction and show the highest relative viscosity. As a general trend, W/O emulsions show a typical Newtonian behavior at temperatures above the wax ACS Paragon Plus Environment

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appearance temperature (WAT) and at low water cuts. The rheological study shows that temperature, shear rate, water volume fraction and API gravity have important impacts on the viscosity of W/O emulsions.

1. Introduction In crude oil production, oil and co-produced water are mixed due to high shear forces through the wellbore, pumps, choke valves and pipelines from the reservoir to the separation facilities. Thus, the formation of W/O emulsions is ubiquitous in oil field developments. It is well known that the rheological properties of emulsions and their stability are essentially influenced by the volume fraction of dispersed phase, drop size distribution, thermodynamic factors and chemical composition of oil and water.1 The presence of indigenous surfactants in the crude oils, such as naphthenic acids, asphaltenes and resins, and the total mass of volatile aromatic components are known to play an important role in the formation and stability of emulsions.2,3,4 Actually, the role of asphaltenes in the emulsion stabilization process is dimly understood because they cannot stabilize W/O emulsions the way surfactants do, but many papers with solid experimental data provide support to this idea.5,6 Anyway, the variation of crude oil composition explains the large deviation in emulsions viscosity. The key point

is that crude oils normally behave as Newtonian fluids at temperatures above the WAT, but they can show important viscosity variation as a result of both wax solidification and emulsion formation. In addition, the simultaneous formation of gas hydrates7,8 and paraffinic gels during the multiphase flow can lead to important changes in the rheological behavior of the produced fluids. It will thus increase the potential risks of production interruption, especially in deep water scenarios where cold water environment prevail.9 Rheological studies show that temperature, shear rate and water volume fraction have important impacts on the viscosity of W/O emulsion.10 Rheological analyses are an important tool to predicting and curtailing different flow assurance related problems. However, modeling and predicting crude oil ACS Paragon Plus Environment

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emulsion rheological behavior is still challenging. Ronningsen11 established an empirical correlation to calculate the relative viscosity based on North Sea crude oils data taking into account the effect of temperature and water volume fraction. That correlation estimates the relative viscosity of W/O emulsion is about 5-6 at 50% water cut and about 8-9 at 60% water cut. An experimental work with live oils shows that Ronningsen correlation provides reasonable estimates of the relative viscosity of waterin-oil dispersions for a wide range of crude oils and conditions. This correlation can provide an accuracy around 40% for water cuts lower than about 40% and an accuracy around 70% for higher water cuts. Ronningsen correlation, however, appears to be somewhat conservative, except for very concentrated dispersions (water cuts higher than 70%).12 Pal & Rhodes13 and Pal14 presented an empirical equation for viscosity of emulsions based on the concentration of the dispersed phase (up to 74%), at different shear rates, and also reviewed and evaluated theoretical viscosity models for both dilute and concentrated emulsions. Farah15 evaluated the emulsion viscosity as a function of the dispersed phase volume, at constant temperature, using models available in the literature. None of the models tested, however, was entirely satisfactory. Because of that, a viscosity correlation was proposed by Farah to temperatures above and below the WAT and for different volume fractions of dispersed phase. Ersoy et alli16 developed a mathematical model using fundamental thermodynamics and conservation of mass laws to predict the saturation limit (inversion point, in their words) of an emulsion system. The authors considered as the main parameters that govern the emulsion inversion point the surfactants physical and chemical properties, emulsion droplet size and the standard chemical potentials of the liquid phases. Recently, Tjoeng17 presented an empirical modeling of emulsion viscosity as a function of water cut. Emulsion viscosity data, measured in laboratory, were input in a multiphase flow simulator and were compared to field data (flow rate, pressure drop and temperature). Their conclusion was that at low water cuts (< 35%) the modeled emulsion viscosity typically matches the value measured in the laboratory. For water cuts higher than 35%, they found that emulsion viscosity models systematically over-predict measured viscosity data.

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At present, there are no theoretical models available to accurately predict emulsion viscosity as a function of shear rate and water cut. As emulsions are always formed in oil producing wells when water cut is higher than zero, the emulsion viscosity must be determined in a laboratory at different conditions. W/O emulsions of waxy oils may present additional rheology complexity due to paraffinic components precipitation at low temperatures. Despite important modeling advances in emulsion rheology in the oil industry,18 measured data are still required by flow simulators during field development to predict the impact of emulsion formation on the production system. Furthermore, commercial flow simulators are not always up-to-date with latest modeling developments. Notwithstanding, the prediction of stability and rheological behavior of emulsions is relevant to diverse flow assurance related issues. These pieces of information can be used, for instance, to help the production project design, predicting pressure drops along the lifetime of a given well or an entire field and monitoring pump performance. The focus of this paper is to characterize Brazilian crude oils and emulsions at different water cuts, temperatures and shear rates by rotational rheology to preview the flow behavior during production particularly for offshore fields. The results of these analyses can help in the development of new viscosity models. Crude oil gelling tendencies and time-dependent rheology are not covered here.

2. Experimental procedures

2.1. Materials. A matrix of 126 dead crude oils from different Brazilian reservoirs was selected for this study. 2.2. Basic characterization of crude oils. The API gravity was obtained by ASTM D4052 method and the water content of the crude oils was measured by potentiometric Karl Fischer titration (ASTM D4377). The wax appearance temperature (WAT), the highest temperature at which wax crystals begin to form or precipitate from the solution, was obtained by differential scanning microcalorimetry 4 ACS Paragon Plus Environment

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(SETARAM µDSC VII – RMS noise 0.2 µW typical). This temperature is easily identified by the exothermic peak during the sample cool down, in a temperature range from 80 to -10 oC at a 0.8 °C/min cooling rate. The onset temperature is measured by intersection point of baseline and the tangent line of inflection point of the exothermic peak. The calculated temperature is assigned as the WAT. The total heat flow related promoted by wax precipitation is computed by the integration of the area between the DSC calorimeter signal curve and the baseline. 2.3. Emulsion preparation and stability. Crude oil samples were thermally treated (“thermal memory” erasure) in a lab oven at 60 ºC for at least 1 hour to re-dissolve any wax that may have already precipitated. Following, brine at 60ºC was added to the crude oil phase. Water-in-oil emulsions (500 mL total volume) were prepared using synthetic brine consisting of 5.0 wt% NaCl in Milli-Q water (brine), at aqueous volume fractions of 10, 30, 50 and 70%. Emulsification was performed using a homogenizer Polytron PT3100 at 8,000 rpm for 3 minutes. This condition was previously defined based on studies comparing the drop size distribution of field-produced and laboratory-prepared emulsions. Subsequently, a series of bottle tests were performed at 60 ºC to visually determine emulsion stability during 4 hours to check the stability in case of production stoppage.

2.4. Rheological analysis. Crude oils viscosity was measured on a rotational lab rheometer at different temperatures and shear rates. Rheometric measurements were performed using a Haake controlled-stress rheometer - Thermo Fisher Scientific. The viscosity was measured using coaxial cylinder geometry (Z20 or Z10 sensors), while the sample was cooled at a programmed cooling rate (-1ºC/min) from the starting temperature (60ºC) to the hold temperature (4ºC). The range of the applied shear rate was 20– 250 s−1. The rheological procedure is performed by shear rates step by step (20, 50, 80, 120 and 250 s1) at each temperature (60, 50, 40, 30, 15, 12, 8 and 4 ºC). The same experimental procedure was applied to water-in-oil emulsions with different API gravity and water cuts in the range of 10 to 70%.


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This method is shown to be a useful way to obtain crude oil emulsions viscosity on a small-scale lab apparatus. The viscosity data at 50, 30 e 4ºC were selected as representative examples. The emulsion viscosity ( η E ) holds a direct relationship with the viscosity of its continuous phase ( η EP ), the oil phase. Thus, the emulsion viscosity was also reported as relative viscosity ( η R ), calculated by equation 1. This equation is an approximation and will never hold at the deformation extremes nor composition extremes. For example, near the inversion point.

ηR =

ηE η EP

(1)

3. Results and discussion 3.1. Basic characterization of crude oils Table 1 shows the basic crude oils properties. The API gravity of crude oil samples hovers from 13.1 to 35.7º. As can be observed, a few crude oils have two wax crystallization temperature events (WAT1 and WAT2) while the majority of crudes shows only one WAT event. To our best understanding, the first WAT event, observed at around 40°C, represents the crystallization of the higher molar mass paraffins. The second WAT event, in general, detected around 25°C has been ascribed to the crystallization of the lower molecular weight paraffinic compounds and involves larger amounts of heat exchange. All the oils data presented in Table 1 were taken into account to draw the conclusions on the general behavior of those fluids. The analyses presented in the next sections are supported by few selected data over the 126 samples.

3.2. Rheological analysis


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Absolute viscosity provides a measure of the fluid resistance to flow. In the flow assurance area in offshore fields, viscosity data is required for the range of temperatures from the wellbore to the seawater, which is the minimum temperature that fluids are submitted to in case of production shutdown. Figures 1 to 3 show the dead crude oils and emulsions viscosity, at 50 s-1, versus API gravity at different temperatures and up to the water cut of 70%. As expected, the lower API gravity of crude oil the higher are both dehydrated crude oil viscosity and emulsion viscosity. The data show that viscosity of W/O emulsion is strongly augmented by increasing the volume of incorporated water and decreasing the temperature (see selected examples in Figures 7 to 14). When increasing the temperature, it is observed a decrease in viscosity of emulsion caused by a decrease in oil viscosity. Results showed that the viscosity noticeably increases with the water content as result to increase the number and volume of dispersed water droplets in the continuous phase (oil).19 As the water volume fraction increases, the viscosity increases gradually until the emulsion is about 30% water cut. Beyond that value, additional emulsified water abruptly increases emulsion viscosity (Figure 14), until the water saturation limit, i.e. the maximum amount of water incorporated in the oil. For most of the evaluated oils the water saturation limit occurs at the 70% water content. Higher water cuts result in the appearance of a free water phase in the bottom of the bottle test. It was observed that beyond the water saturation limit there are two liquid phases: the water in oil emulsion and the free water. We do not observe an inversion of the emulsion, which would turn itself into an oil-in-water emulsion. As it can be seen, however, crude oils with similar API gravity and viscosities can generate emulsions with different viscosities and water saturated volume. In Figures 4 to 6 the results of the viscosity tests were expressed as relative viscosity, i.e., the ratio of the emulsion viscosity at a given temperature, to the crude oil viscosity at the same temperature (eq. 1). The relative viscosity was around 1.3 for 10% water cut and around 2.8 for 30% at 50ºC, 30ºC and 4ºC. Above 30% water cut there is a much large spread in the relative viscosity values, from 5 to 110, the effect of chemical composition, specifically the content of interfacial active compounds in the oil, in


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addition to API gravity and temperature, becomes important in those stable high water cut emulsions. At 70% vol brine fraction the relative viscosity was 8 to 110 (the most extreme case) at 50ºC and 4 to 70 at 4ºC. Results of tests carried out at different temperatures show that the relative viscosity is dependent on the temperature and crude oil properties. The crude oils compositional chemical variation reflects in an extremely large viscosity range from 0.01 to 500 Pa.s, and rheological behavior from Newtonian to nonNewtonian. It is also observed that the largest increase in relative viscosity occurs with crude oils gravity between 20 and 30ºAPI (see Figures 4 to 6), probably due to the presence of wax crystals covering the liquid–liquid interface (decreasing the tendency to coalesce)20 which is believed to partially eliminate the free movement of the droplets within the emulsion. As shown by the large amount of scatter in each curve, the emulsion viscosity is very sensitive to crude oil composition characteristics. Visintin et alli20 shows that the presence of water above a threshold value can greatly enhance gel formation, changing both the emulsion pour point temperature and the yield strength. Further considerations were made about emulsion stabilization capability of solid paraffins. The wax particles can be strongly adsorbed at the liquid–liquid interface, increasing the interfacial film viscosity and reducing the coalescence of the drops forming Pickering emulsions. By the same token, gel formation is favored when the wax spans the dispersed water. The correlation11 used to predict viscosity of W/O emulsions based on North Sea crude oils predicts emulsions relative viscosities about 5 to 6 at 50% water cut, while for the Brazilian crude oils emulsions evaluated in the lab show relative viscosity about 5 to 15 at the same water cut. That correlation provides a fairly-accurate initial estimate of the effective emulsion viscosity up to 50% volume of water, but above this value the differences between the calculated and measured values become more dependent on crude oil characteristics. Figures 7 to 13 show examples of the viscosity as function of shear rate (20 to 250 s-1) at different temperatures (60ºC to 4ºC) and at fixed volume fraction of dispersed phase (50%) for some selected crude oils. For temperatures below the WAT, or the second event of wax crystallization in some cases, ACS Paragon Plus Environment

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the viscosity varies with shear rate, indicating that the dehydrated oil and their emulsions behave as nonNewtonian fluids. A notable increase in viscosity below the WAT at low shear rates can be observed specially for waxy crudes, as shown in figures 9 and 13, crude oils #37 and #113, respectively. Those crude oils have high WAT. It can also be observed that the viscosity of the dehydrated oil is practically independent of the shear rate at temperatures above the WAT. This is valid for all tested crudes. For some crude oils the viscosity variation with the shear rate (shear thinning behavior) is not observed throughout the temperature range, as per crudes #23 and #49, for example (Figures 8 and 10). Some emulsions exhibit shear thinning behavior at high water cut, due to the close drops packing, as crudes #49 and #99 (Figures 10 and 12). Research works have led to a comprehensive understanding of the behavior of different emulsified systems. Notwithstanding, there are still many unanswered questions on the peculiar behavior of crude oil emulsions. For instance, the mechanisms by which some surface-active molecules indigenous to crude can act as emulsifying agent is not precisely known yet. Experimental studies, however, show that asphaltenes molecules are prone to form mechanically rigid or viscoelastic interfacial films around water droplets, which contributes to the high stability of petroleum emulsion. Also, the higher viscosity of the emulsions stabilized by hydrophobic particles is due to the fact that hydrophobic particles are more attracted to each other in the oil phase than hydrophilic particles in the aqueous phase.21,22 As a general rule, emulsions often behave as non-Newtonian fluids and their viscosity, near the inversion point, can be several orders of magnitude higher than the one of the continuous phase. The elevated emulsion viscosity causes an additional frictional pressure drop in the well tubing and subsea flow system, reducing the full capacity of oil production. From the perspective of emulsion stability and flow assurance, all analyzed crude oils are promising candidates for emulsion transport of hydrate particles at low temperature and elevated pressure conditions.7 Wax gelling associated with production shutdowns may be real problematic when emulsified water is present in the oil. This may lead to extreme situations in which the pipeline simply cannot be restarted because of the presence of a strong ACS Paragon Plus Environment

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waxy oil emulsion gel, requiring excessively high starting pressure (Oliveira et alli,23 Normam et alli,24 Mendes et alli,25 Vinay et alli26 for more detailed discussion on this subject). Therefore, anticipated rheological studies are mandatory to address pipeline restart related problems. 4. Conclusions W/O crude oil emulsion can cause high pressure drops, resulting in transportation, pumping and separation hurdles. After having analyzed the experimental data obtained from 126 crude oils and their respective emulsions at different temperatures and dispersed phase volume fractions, we can come with the following conclusions: •

Experimental data on emulsions viscosity present a wide range of values, even for emulsions with the same water cut. This is mostly dictated by crude oil characteristics and composition. It explains why is difficult to correlate typical black oil parameters with the relative viscosity of emulsions formed by different API gravity crudes and different water cuts;

•

Emulsions prepared with different crude oils with the same API gravity, for example, show relative viscosity ranging from 8 to 110 at 70% water cut. It was observed that the largest increase in viscosity occurs with crude oil gravity approximately between 20 and 30ºAPI;

•

The temperature variation from 50 till 4°C shows a significant effect on the viscosity of these crude oils and emulsions;

•

The effect of wax crystals, for temperatures below WAT, seems to disturb the crude oil emulsions viscosity, providing non-Newtonian behavior and adding complexity to the emulsion system;

•

The best approach to deal with emulsion formation problems during crude oil production is to perform lab tests to evaluate the emulsion rheological behavior and stability in the temperature and water cut ranges expected in field lifetime conditions; to select subsea chemical products to reduce emulsion viscosity and to anticipate the emulsion breaking process and a combination ACS Paragon Plus Environment

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of experimental investigations and tailor-made mathematical modeling shall improve models prediction capability and subsequent optimization of operations in challenging offshore developments with multiphase flow scenarios. ACKNOWLEDGMENTS: The authors thank the technical support of Lenise Couto Vieira (µDSC analysis), Luiz Carlos do Carmo Marques and Rafael Mendes for revising this text, and PETROBRAS for permission to publish this work.


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Table 1. Crude oils API gravity, WAT and relative viscosity Crude oil Sample

API

WAT1 (ºC)

WAT2 (ºC)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53

13.1 14.4 15.6 15.9 16.3 16.4 16.8 16.9 17.0 17.6 17.8 18.0 18.2 18.3 18.6 18.7 18.7 18.9 19.0 19.2 19.4 19.6 19.7 20.4 20.5 21.0 21.1 21.1 21.3 21.3 21.8 21.9 22.1 22.3 22.4 22.8 24.0 24.1 24.2 24.3 24.3 24.7 24.8 24.9 25.2 25.3 25.4 25.4 25.7 25.8 25.9 25.9 26.2

11.9 3.1 53.8 x 15.5 15.2 14.6 18.8 47.6 19.7 7.9 14.4 x 13.6 15.1 15.7 17.7 34.0 25.5 17.8 15.2 x 13.9 18.7 39.3 17.2 44.3 16.2 16.3 41.6 12.1 16.2 13.6 15.8 x 29.8 45.4 15.8 43.4 14.0 14.1 32.3 x 36.6 37.2 21.3 34.7 35.1 41.8 40.7 34.6 x 29.4

22.1 x 19.5 x 18.6 18.2 x 17.3 12.5 18.8 x 14.7 25.3 17.7 15.9 x 16.9 18.9 12.6 17.2 17.2 17.9 20.8 17.2 x 14.0

Relative viscosity Emulsion 50% 50ºC 30ºC 4ºC

Relative viscosity Emulsion 70% 50ºC 30ºC 4ºC

# 6.0 8.7 8.9 6.5 6.7 7.2 5.4 7.9 7.7 7.1 9.4 10.0 9.7 6.9 7.5 5.1 5.8 10.7 10.4 8.7 11.2 6.4 8.4 21.1 8.5 10.8 8.1 8.4 13.0 7.1 7.2 7.3 5.9 12.1 8.6 8.5 12.4 15.5 9.2 8.9 8.9 7.5 13.6 7.8 7.1 10.1 10.0 12.5 7.6 6.8 9.5 9.5

# # # 27.8 12.8 # 17.3 8.1 38.6 16.1 28.6 # 30.3 13.1 20.5 31.1 14.6 36.0 43.3 # 46.8 36.5 9.7 34.8 110.3 33.8 66.0 52.5 27.5 39.5 20.0 31.5 25.2 11.6 58.4 53.2 14.6 44.6 80.1 29.7 36.7 63.8 25.0 68.4 35.2 27.3 73.6 60.9 90.4 20.7 37.4 48.4 49.9

# 4.0 8.1 7.1 6.1 6.0 6.5 4.8 8.1 7.3 6.6 9.7 8.8 8.9 6.3 6.6 4.4 4.9 12.3 9.4 9.1 12.8 5.6 8.5 23.1 8.6 10.9 8.0 7.4 14.7 7.0 6.7 6.8 4.9 13.3 9.8 8.3 13.9 13.6 9.7 9.3 10.5 7.6 13.5 8.3 6.5 10.8 12.0 13.4 6.8 6.6 10.4 10.7

# 3.4 4.1 5.3 5.3 4.7 5.7 3.5 6.4 6.7 5.5 8.5 6.7 7.3 4.4 4.9 3.9 3.7 9.9 7.4 8.2 14.1 4.8 8.1 18.2 7.8 8.9 7.3 5.9 12.2 7.2 6.0 5.5 4.1 7.5 12.8 4.3 14.0 9.5 10.6 9.9 10.3 6.7 10.4 7.3 5.9 9.8 11.1 10.8 5.0 5.9 5.8 8.9


# # # 15.4 6.6 # 10.6 6.3 31.8 13.6 28.8 # 22.5 11.8 15.1 21.6 13.2 25.0 40.6 # 34.1 33.5 7.3 29.6 73.8 27.9 55.2 37.9 20.4 40.0 17.2 24.7 20.0 9.4 49.3 59.3 14.1 44.7 73.0 24.5 31.6 80.8 21.7 46.8 34.7 19.5 67.4 59.0 89.2 17.2 30.3 43.6 40.6

# # # 6.5 0.1 # 7.2 3.8 8.8 14.6 9.2 # 9.3 8.1 10.1 12.8 10.6 13.1 25.5 # 11.6 30.6 6.4 23.8 33.5 21.2 28.6 23.5 15.2 26.8 14.8 16.9 13.7 6.4 18.4 58.6 6.3 42.5 35.7 25.1 25.1 58.7 17.7 21.5 19.0 11.8 42.0 40.7 56.7 10.4 17.6 15.5 18.9

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26.4 26.6 26.6 26.6 26.6 26.6 26.7 26.8 26.9 27.2 27.2 27.3 27.4 27.4 27.4 27.4 27.5 27.5 27.5 27.6 27.6 27.7 27.7 27.7 27.8 27.8 27.8 27.9 27.9 27.9 28.0 28.0 28.1 28.2 28.3 28.3 28.3 28.4 28.5 28.5 28.6 28.6 28.6 28.6 28.6 28.8 28.8 28.8 29.0 29.1 29.1 29.2 29.4 29.7 29.7 30.1 30.2 30.2

40.9 17.8 46.7 39.6 28.4 39.2 x 26.9 43.3 31.6 42.2 41.1 x 36.0 12.0 35.5 46.6 53.6 39.4 43.3 43.8 41.3 42.4 12.7 41.6 30.9 41.1 34.9 40.6 39.3 42.0 41.1 43.0 32.3 28.3 53.6 31.1 41.8 38.5 35.9 35.6 34.0 41.9 32.9 33.5 37.4 26.5 43.6 36.4 31.7 32.0 41.7 x 37.5 39.0 45.8 37.8 40.2

20.8 25.2 21.1 14.8 20.5 x 12.6 18.3 12.9 17.7 17.4 x 19.8 16.5 21.8 26.6 18.8 19.2 18.8 19.1 17.6 17.3 14.8 21.0 16.4 20.2 17.3 19.6 21.0 19.7 14.4 13.2 26.6 17.2 21.5 20.8 15.8 19.3 12.6 20.0 15.2 16.4 19.9 12.8 20.4 18.8 20.8 15.9 19.4 x 20.2 20.8 20.6 19.8 20.6

8.0 8.1 12.4 8.0 7.7 12.6 9.9 8.4 16.8 9.6 13.0 13.0 5.2 8.7 9.4 5.7 9.1 12.8 6.0 12.1 7.4 14.2 14.3 6.9 12.9 11.0 7.8 14.6 8.7 17.6 16.7 7.8 7.3 11.6 9.5 12.5 10.3 9.8 6.4 13.9 9.5 6.8 9.9 10.9 10.4 15.7 13.8 9.0 9.3 10.0 15.6 8.6 9.4 10.8 8.6 7.2 13.6 7.4

8.6 8.3 12.1 7.5 7.6 12.5 10.3 9.4 13.6 10.1 12.6 10.2 4.4 8.6 8.2 4.7 7.9 11.4 5.6 9.9 6.9 12.8 15.9 6.5 13.6 13.2 8.0 16.6 7.1 16.5 15.5 7.4 6.9 14.0 9.9 12.4 11.7 11.3 5.4 12.6 4.6 5.9 9.1 11.6 12.5 14.3 12.5 7.8 8.6 7.8 7.6 9.0 9.0 8.2 6.9 7.8 17.7 7.1

6.5 9.2 3.8 4.5 6.9 7.9 10.8 8.2 8.6 8.6 8.6 5.3 4.7 6.6 7.4 3.4 5.6 10.5 6.5 4.6 6.4 5.4 7.8 6.1 8.1 10.7 4.1 8.5 2.7 15.6 6.0 4.6 4.1 12.5 8.1 8.9 6.8 7.5 3.8 9.4 4.9 5.0 5.7 7.9 9.8 4.8 11.9 5.3 4.7 4.8 8.3 4.8 5.3 3.2 0.6 2.6 4.7 4.0


16.1 42.9 47.4 15.1 40.3 30.9 23.1 19.6 77.0 18.6 95.5 78.6 16.1 19.3 20.1 12.4 35.9 27.6 17.4 38.1 26.3 45.1 40.4 21.7 85.9 43.4 32.8 96.4 36.8 71.1 50.7 23.5 19.4 31.8 41.7 46.0 24.8 29.0 16.0 49.9 23.5 19.5 26.4 63.7 75.9 62.8 34.9 16.3 22.0 59.3 22.1 17.5 41.8 # 18.8 35.8 32.1 16.4

15.2 37.0 44.9 13.9 30.9 29.0 22.3 19.3 56.2 16.0 83.4 56.9 12.4 19.2 17.7 12.2 26.1 23.0 18.7 28.0 22.0 35.4 36.0 17.8 78.7 44.4 34.2 89.8 27.6 160.7 41.9 19.6 16.3 33.0 36.4 41.1 19.2 28.3 15.4 40.0 14.3 17.0 22.0 51.6 43.9 54.2 25.0 12.7 19.1 45.6 15.5 21.2 29.7 # 20.8 30.0 27.3 13.6

11.1 36.1 5.8 6.4 19.6 15.0 19.6 16.7 23.7 8.9 29.0 16.7 11.5 14.7 13.8 9.3 10.1 19.2 21.4 9.9 19.1 12.4 13.7 14.8 32.7 31.4 10.5 33.0 5.9 69.8 8.9 9.7 8.8 30.2 24.0 20.7 16.3 14.5 6.2 24.4 12.5 13.2 10.7 23.5 42.0 10.8 22.1 7.0 14.2 18.5 0.0 8.0 9.5 # 9.4 4.0 5.7 5.3

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112 30.4 37.6 17.9 113 30.5 40.6 20.7 114 30.5 36.1 19.8 115 30.6 39.8 19.7 116 30.8 38.3 20.2 117 31.0 38.9 17.3 118 31.3 47.8 20.1 119 32.0 37.8 18.9 120 32.1 38.8 20.1 121 32.1 40.8 18.5 122 32.2 44.9 24.0 123 33.1 x x 124 33.8 45.6 22.6 125 33.9 39.5 16.4 126 35.7 28.8 18.6 x- analysis not performed # emulsion unstable.

5.7 8.2 7.2 9.6 7.0 13.3 8.7 9.4 4.9 7.7 13.2 7.1 11.0 5.5 7.2

4.9 9.2 8.3 10.2 6.4 12.2 8.7 10.0 5.0 7.4 11.8 6.1 7.7 5.1 0.0

Page 14 of 22 3.4 7.6 8.4 6.1 7.3 8.0 3.1 3.8 3.7 3.2 3.9 4.3 2.5 6.9 4.5

17.4 35.0 21.7 25.2 22.4 34.0 35.6 22.9 13.1 # 44.4 22.0 # # #

7.0 30.3 17.5 18.8 14.4 30.1 31.7 18.8 12.4 # 32.0 17.4 # # #

7.4 11.0 18.7 8.7 10.6 15.8 5.3 4.7 6.2 # 4.8 8.4 # # #

Figure 1. Viscosity of different API gravity crude oils and their emulsions with different water cuts at 50ºC.


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Figure 4. Relative viscosity of different API gravity crude oils and their emulsions with different water cuts at 50ºC.



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Figure 7. Crude oil #8 (16.9ºAPI) and emulsion viscosity at 50% volume water fraction versus temperature at different shear rates.


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Figure 8. Crude oil #23 (19.7ºAPI) and emulsion viscosity at 50% volume water fraction versus temperature at different shear rates

Figure 9. Crude oil#37 (24.0ºAPI) and emulsion viscosity at 50% volume water fraction versus temperature at different shear rates


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Figure 12. Crude oil#99 (28.8 ºAPI) and emulsion viscosity at 50% volume water fraction versus temperature at different shear rates



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Figure 14. Relative viscosity of Crude oils#19, #25, #81, #103, and #122 versus water cut at 30 ºC.

REFERENCES

1

Moradi, M.; Alvarado,V.; Huzurbaz, S. Energy Fuels. 2011, 25, 260–268. DOI:10.1021/ef101236h.

2

Abdel-Raouf, M. E; Factors affecting the stability of crude oil emulsions in crude oil in emulsions – composition stability and characterization. Published by InTech. 2012. 3

Zhang, J.; Tian D.; Lin, M.; Yang, Z.; Dong, Z. Colloids and Surfaces A: Physicochem. Eng. Aspects. 2016,

507, 1–6. 4

Wong, S. F; Lim, J. S; Dol, S. S. Journal of Petroleum Science and Engineering. 2015, 135, 494-504.

5

Czarnecki, J. Energy & Fuels. 2009, 23, 1253–1257.

6

Czarnecki, J.; Khristov K.; Masliyah, J.; Panchev, N.; Taylor S.D.; Tchoukov, P. Colloids and Surfaces A: Physicochem. Eng. Aspects. 2017, 519, 2-10.

7

Kolotova, D., Brichka, K., Simonsen, G., Simon, S. C., Derkach, S. R., Paso, K. G., & Sjoblom, J. Energy & Fuels. 2017, 31, 7, 7673–7681.

8

Salager, J-L.; Forgiarini, A.M. Energy Fuels. 2012, 26, 4027−4033. dx.doi.org/10.1021/ef3001604.

9

Oschmann, H.; Alapati, R.; Paso, K. SPE 164132. 2013.

10

Ariffin, T. S. T., Yahya, E., Husin, H. Procedia Engineering. 2016, 148, 1149 – 1155. ACS Paragon Plus Environment

21

Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

11

Page 22 of 22

Ronningsen, H. P. Correlations for predicting viscosity of w/o emulsions based on North Sea based on North Sea crude oils. SPE paper 28968, SPE Int. Symp. Oilfield Chem. San Antonio, US. 1995.

12

Johnsen, E. E; Rønningsen, H. P. Journal of Petroleum Science and Engineering. 2003, 38, 23– 36.

13

Pal, R.; Rhodes, E. J. Rheology. 1989, 33, 1021-1045.

14

Pal, R. J. Chem. Eng. 2001, 81, 15– 21.

15

Farah, M. A.; Oliveira, R. C. G., Caldas J. N., Rajagopal, K. Journal of Petroleum Science and Engineering. 2005, 48, 169– 184.

16

Ersoy, G.; Yu, M.; Sarica, C. SPE 115610-MS. SPE Projects, Facilities & Construction. 2008.

17

Tjoeng, A.Y.; Loro, R. SPE-182326-MS. 2016.

18

Frigaard, I. A., Paso, K. G., de Souza Mendes, P. R. Rheologica Acta. 2017, 56, 3, 259-282.

19

Trados, T.F. Emulsion Formation and, Stability. 2013, Wiley-VCH.

20

Visintin, R.F.G.; Lockhart, T. P.; Lapasin, R.; D’Antona, P. Journal of Non-Newtonian Fluid Mechanics. 2008,

149, 1-3, 34-39. 21

Paso, K., Silset, A; Sørland, G., Gonçalves, M. A; Sjoblom, J. Energy & Fuels. 2009, 23, 471–480.

22

Kilpatrick, P. Energy & Fuels. 2012, 26, 4017-4026.

23

Oliveira, G. M; Negrão, C.R.O.; Franco, A.T. Journal of Non-Newtonian Fluid Mechanics. 2012, 169-170, 121-125.

24

Norrman, J.; Skjæraasen, O.; Oschmann, H. J.; Paso, K.; Sjöblom, J. Physics of Fluids. 2016, 28, 3, 033102.

25

Mendes, R.; Vinay, G; Coussot, P. Energy Fuels. 2017, 31, 1, 395–407.

26

Vinay, G.; Wachs, A.; Agassant, J-F. Journal of Non-Newtonian Fluid Mechanics. 2006, 136, 2–3, 93-105.


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VISCOSITY OF WATER-IN-OIL EMULSIONS FROM DIFFERENT API

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