experimental study of phase inversion phenomena in

Journal of Offshore Mechanics and Arctic Engineering

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OMAE-17-1150 Bulgarelli, N. A. V.

Experimental Study of Phase Inversion Phenomena in Electrical Submersible

Pumps under Oil/Water Flow Natan Augusto Vieira Bulgarelli School of Mechanical Engineering, University of Campinas, Rua Mendeleyev, 200, Cidade Universitaria, Campinas, São Paulo 13083-860, Brazil [email protected] Jorge Luiz Biazussi Center for Petroleum Studies, Rua Cora Coralina, 350, Cidade Universitaria, Campinas, São Paulo 13083-896, Brazil [email protected] William Monte Verde Center for Petroleum Studies, Rua Cora Coralina, 350, Cidade Universitaria, Campinas, São Paulo 13083-896, Brazil [email protected] Marcelo Souza de Castro School of Mechanical Engineering, University of Campinas, Rua Mendeleyev, 200, Cidade Universitaria, Campinas, São Paulo 13083-860, Brazil [email protected] Antonio Carlos Bannwart School of Mechanical Engineering, University of Campinas, Rua Mendeleyev, 200, Cidade Universitaria, Campinas, São Paulo 13083-860, Brazil [email protected] ABSTRACT

Despite the common presence of water in oil production, just recently, the scientific community has

devoted efforts to studying the influence of emulsion phenomena effects related to oil production using

pumps. In the context of this study of phase inversion phenomena, the influence of viscosities and

rotational speeds in Electrical Submersible Pumps (ESPs) are evaluated as part of this effort. This study is

aimed at investigating the influence of viscosity in phase inversion phenomena. An 8-stage ESP was tested

with three different rotational speeds and two different oil viscosities for the best efficiency point (BEP)


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flow rates. Initially, the total flow rate was obtained in relation to BEP using ESP performance curves for

pure oil at 52 cP and 298 cP and rotational speeds of 800 rpm, 1200 rpm and 2400 rpm. The total flow rate

was kept constant and the water cut was increased from zero to a hundred percent. The inversion phase

phenomenon was detected by the performance improvement when the water cut increased. The factors

analyzed were the head and efficiency of the ESP as a function of the water cut. The phase inversion

experimental data obtained in this study was compared with literature models for horizontal pipes. The

results of this comparison presented satisfactory agreement. The phase inversion phenomena occur in all

8-stage at same time. Hysteresis was observed in ESPs for oil viscosity of 52 cP and rotating speed of 800

rpm and 1200 rpm.

1. INTRODUCTION

An Electrical Submersible Pump (ESP) is a method of artificial lift that stands out

for great production and wide application in several scenarios. The oil exploration

industries use the ESP in conjunction with an electric motor, sensors and other

equipment allowing remote operation of the system. The ESP operates with mixtures

characterized by multiphase flows of gas-liquid (gas-oil), liquid-liquid (oil-water) and gas-

liquid-liquid (gas-oil-water) in oil extraction. Liquid-liquid mixtures are observed in many

industrial and natural processes; the mixtures can be composed of two immiscible

phases with flow patterns arranged in various geometric configurations. When well

mixed, they are known as emulsions and have greater viscosity than the pure oil. An

emulsion is composed of a dispersed phase and a continuous phase. Formation of

emulsion takes place in the oil-water flow. This emulsion can be oil-in-water, the oil is

the dispersed phase, or water-in-oil, the water is the dispersed phase. The properties of


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emulsions depend on which phase is dispersed. The boundary that separates the two

types of dispersion (oil-in-water and water-in-oil) is the phase inversion point. A physical

property affected by the continuous phase in emulsion is the viscosity. Factors like

viscosity of the oil and water, water content, temperature, droplet size distribution and

shear rate can influence the apparent viscosity of the emulsion [1]. The apparent

viscosity directly affects the lift performance of the ESP [2].

Several phenomena related to the multiphase flow inside pumps such as

foaming, cavitation and emulsion still have unknown effects on ESP performance. For

high flow rates of liquid and high oil fractions, the pump has similar performance to that

observed in oil single-phase flows. Therefore, the performance suffers degradation

when the pump operates with high viscosity liquids or with emulsions. The presence of

water generates emulsions within the ESP impeller that strongly affect the lift capacity.

The formation of stable emulsions in the oil lift process affects the performance of oil

separators on platforms, which considerably increases the time and energy required to

separate the phases.

The study of oil-water emulsion in ESPs is recent, so there are no references in

the literature about subject. The liquid-liquid (oil-water) flow in pipes, which usually

occurs in the petroleum industry, has been investigated by several research studies [3-

5]. Reference [3] studied oil/water flows in horizontal pipes via various experiments

using a wide range of oil viscosity. They proposed a correlation in predicting the phase

inversion point. They also observed that the main factor that influences the inversion

point is oil viscosity, and the water fraction input required to invert the dispersed phase


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increases with decreasing oil viscosity. A sudden drop in pressure loss due to friction

when the continuous phase changed from oil to water was also observed [3]. The

correlation in predicting the phase inversion point of an oil-water system was applied in

various experimental data in the literature and provided satisfactory results.

Reference [4] analyzed the phase inversion phenomenon in oil-water flow and its

effects on pressure loss in pipelines composed of two materials (steel and acrylic) and

two pipe diameters (60 and 32mm i.d.). They observed that the mixture velocity and

initial conditions (water in-oil or oil-in-water emulsion) modify the phase inversion point

(hysteresis effect). The effect on pressure loss was the same as observed by [3].

The other methodology to predict phase inversion in pipelines was proposed by

[5]. This method consists of comparing the apparent viscosity when oil or water are the

continuous phase. The phase inversion point is determined when these apparent

viscosities are equal. Various correlations presented in literature to predict the mixture

viscosity were used. Among the analyzed correlations, [6-9] predicted inversion within

the experimental phase inversion range. This methodology was also compared with

critical phase fraction models from literature. A satisfactory result was obtained

between [5, 10] as well as for experimental data for a range of oil viscosities.

Recent studies on ESPs were done by [2, 11] for single-phase flows and [12] for

gas-water two-phase flows.

In this research, the effects of phase inversion within an 8-stage ESP was

investigated, mainly, at efficiency and lift capacity (head) as a function of the water cut

(water fraction at emulsion). The phase inversion point was compared with the


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correlation developed by [3]. The experimental data was collected in a flow loop facility

specially designed for ESP performance testing with oil-water emulsion flow (Figure 1).

2. MATERIALS AND METHOD

The experimental study was conducted at LabPetro - Experimental Laboratory

for Petroleum "Dr. Kelsen Valente" at the University of Campinas – Brazil, in a flow loop

facility specially designed for ESP performance testing with oil-water emulsion flows. To

carry out the tests mineral oil was used at two viscosities, 298±1 cP and 52±1 cP.

Initially, the efficiency and head curve of the ESP was obtained for pure oil at two

temperatures and at three ESP rotating speeds (800 rpm, 1200 rpm and 2400 rpm). The

rotational Reynolds range tested was from 3 × 103 to 3 × 106. The first curve is

determined by ESP efficiency as a function of the flow rate dimensionless. The other

curve is composed of the dimensionless head in function of the dimensionless flow rate.

With two curves it is possible to analyze the ESP performance. These curves are

determinants which maintain the temperature and ESP rotating speed and vary the total

flow rate.

The ESP efficiency curve is used to obtain the best ESP operation point, relating

to the lifting capacity and the total flow rate which provides the best performance. This

point is designated Best Efficiency Point (BEP). The viscosity and rotating speed variation

directly affect the ESP efficiency curve. Thus, the BEP varied with the rotation and


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temperature, and consequently, the total flow rate changes for each operating

condition.

The standard test procedure started with oil as continuous phase and finished

with water as continuous phase. Both fluids were joined in the “T” intersection where

the water was injected into the bottom of the pipe and flow to ESP inlet, as presented in

Figure 1 (black box).

The ESP experimental setup has two main lines, one for water and the other for

oil. Both lines have an oil/water separator tank, a booster pump to move the fluid from

the tank to the ESP inlet, coriolis flow meters (manufactured by Micromotion with

accuracy of 0.02%), choke valves and differential pressure transducers (Rosemount

2088, manufactured by Emerson and with accuracy of 0.08% F.S.). Only the oil line has a

heat exchanger and a water cut meter (Nemko 05 ATEX 112, manufactured by ROXAR

and with accuracy of 1% F.S.). The fluids are mixed at the intersection between the oil

and water line prior to the ESP inlet. This mixture goes through the 8-stage ESP (Baker

Hughes P100LS with characteristic diameter of 0.108 m), and then enters the return line

that connects it with the oil/water separator tank. The inlet temperature (Ti) was

measured and controlled by a resistance temperature detector, type PT100

manufactured by Ecil and with 1/10 DIN accuracy.

The oil injection was carried out by a progressive cavity pump and the water by a

centrifugal pump. Before mixing the oil and water, the water fraction contained in oil

flow is verified using the water cut meter present in oil line. After that, water is added


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until it reaches the desired water cut. For each acquisition data point it is necessary to

await the stabilization of the ESP pressure gradient and the inlet temperature.

To analyze and compare different rotating speeds and total flow rates in

centrifugal pumps, dimensionless analyses of flow machines should be used. Using the

Buckingham’s Pi Theorem one might obtain Equation 1 which corresponds to

dimensionless head and Equation 2, to dimensionless flow rate. Thus, one can normalize

this factor to other scales for all rotating speeds and total flow rates.

2 2m

e

P

D

(1)

3

q

D

(2)

The static pressure difference is used to calculate the dimensionless head, once

the elevation and the dynamic pressure between the pump inlet and outlet are

negligible.

The emulsion density is obtained using Equation (3) based on homogenous

model [13].

1e w w w of f (3)

The ESP efficiency is calculated by the ratio between the hydraulic power and

shaft power (Equation 4).

e

s

q P

W

(4)


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Equation 4 presents the correlation presented by [3] which was used to compare

the phase inversion experimental data and it is analyzed if can be used for oil/water

flow through ESPs.

, 0.500 0.1108log ow INV

w

f

(5)

3. RESULTS

Experiments with oil temperature variation were performed to investigate oil viscosity

influence. The first step was to find the function of oil viscosity with temperature to find

out what temperature is necessary to achieve some level of viscosity. The oil viscosity

curve function with the temperature is presented in Fig. 2.

2.1. ESP Single-phase curves with pure oil

Previously, the ESP’s efficiency and head curves for pure oil were experimentally

obtained. Fig. 3, 4 and 5 represent the ESP head curves for three rotating speeds, 800

rpm, 1200 rpm and 2400 rpm, respectively, in two oil viscosities (52 cP and 298 cP).

With the decrease in viscosity, the ESP lift capacity is improved, as observed in Fig. 3, 4

and 5.

The ESP efficiency curves are shown in Fig. 6, 7 and 8, the head curves for the same

parameters.


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With the ESP efficiency curves, it is possible to determine the BEP for each rotating

speed and temperature. With the function of the efficiency curves as a function of the

dimensionless flow rate, the BEP might be obtained by matching the zero-derivative

point of these functions in relation to dimensionless flow rate. Thus, the peak point of

the ESP efficiency curve can be determined.

The operating conditions obtained are presented in Table 1.

2.2. Effect of phase inversion in ESP head

Two-phase liquid-liquid experiments were performed, as presented in Table 1. In Fig. 9,

10 and 11, the dimensionless head is presented as a function of the water cut for 800,

1200 and 2400 rpm. The rotational speed, the total flow rate, and the temperature were

kept constant during the experiments. Then, the head behavior of the ESP with two

different viscosities is compared for the same rotational speeds.

In these experiments, the water cut was increased from zero to one hundred percent.

For low water cut values, the oil is the continuous phase and lift capacity of the ESP is

low. A sharp increase on ESP head is observed by increasing the water cut. This happens

for all ESP rotational speeds and the hypotheses to explain this behavior is that the

water phase become the continuous phase.

For all experiments, the head was severely affected in the region of low water cut

values, due to the increase of effective viscosity of emulsion when the oil was the

continuous phase. Two distinct levels of head were observed before and after the


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inversion phenomenon, which were delimited by the phase inversion point of the

emulsion within the ESP.

As can be seen, when the oil viscosity decreases, the critical water cut for inversion

increases. The same behavior is observed in oil/water flow in pipes, when the oil has no

surfactants. Note that before phase inversion, the ESP head increases as the oil viscosity

decreases. This effect is caused by the high effective viscosity of the oil (continuous

phase). Because of that, the ESP lift capacity is heavily affected by the viscous flow

(Reynolds number decreases). After phase inversion, the effective viscosity decreases

abruptly (Reynolds number become bigger), and the dimensionless head becomes a

function of the dimensionless flow rate only (Ψ=f(Φ)).

Comparing the BEP flow rate for each oil viscosity, for all ESP rotational speeds tested

the total flow rates were higher for 52 cP than 298 cP. The dimensionless head was

higher for 298 cP than 52 cP, as expected by similarity rules. But, for oil as continuous

phase there was an opposite behavior, which the smaller oil viscosity (high rotational

Reynolds) presented higher head capacity than more viscous oil.

2.3. Effect of phase inversion in each ESP stage

The phase inversion phenomenon can be observed for each ESP stage and have the

same behavior that was shown by Fig. 9, 10 and 11. Fig. 12 presents the dimensionless

head for each ESP stage as a function of the water cut for 2400 rpm at oil viscosity of

298 cP.


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It is shown that the phase inversion occurs at the same water cut for all ESP stages, and

at the same time. In addition, the first stage presented the better performance before

phase inversion when compared with the others stages of ESP. The hypothesis that

could explain this difference is that first stage has segregate flow in the inlet, and the

others are under emulsion/dispersion flow. Specific tests to confirm the assumptions

are necessary and will help for a better understand of this phenomenon.

2.4. Comparison between ESP experimental data with the correlation proposed by [3]

Fig. 13 and 14 shows the dimensionless head comparison of the different rotational

speeds for the same oil viscosity using the oil A. The black line represents the phase

inversion point calculated by the model of [3].

For the 298cP oil (Fig. 13), the model presented a small deviation from the experimental

data. This difference might have occurred because of correlation was fitted with only

two high viscosities – 237 cP and 2116 cP oils. For the 52cP oil viscosity (Fig. 14), the

model compares satisfactorily with the ESP experimental data. An important finding is

that the ESP rotational speed does not affect the phase inversion point.

Other factors that influence the observed deviation are the average drop size, drop size

distribution and turbulent flow within ESP. Detailed studies are needed for each factor.

2.5. Effect of phase inversion in ESP efficiency


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Another important ESP parameter affected by water cut is ESP efficiency, mostly caused

by the increasing of viscous degradation (Fig. 6, 7 and 8) due to emulsion formation. Fig.

15, 16 and 17 shows the efficiency behavior as a function of the water cut for each

rotational speed for the two oil viscosities (52 and 298 cP).

For the lowest water cut values, the efficiency is similar to that of the ESP operating with

single-phase oil flows. Along with the phase inversion, ESP efficiency increases abruptly

and, after completed the process, the efficiency continues to rise as the water cut

increases until it reaches that of the ESP operating with single-phase water flow.

The same influence of the phase inversion phenomenon is observed in head capacity

and ESP efficiency due to the change of the emulsion viscosity, this can be observed in

the viscous degradation curves. There is a great improvement in both factors when the

ESP operates with emulsions in which the continuous phase is water.

The same influence of the phase inversion phenomenon is observed in head capacity

and efficiency due to viscosity emulsion variation. There is a great improvement in both

factors when the ESP operates with emulsions in which the continuous phase is water.

It is possible to observe that even after the phase inversion point, the ESP efficiency

operating oil-in-water emulsion is lower than water, especially for low ESP rotational

speeds and high oil viscosities. This could be explained due to turbulent energy

dissipation (shear rate) to break the continuous oil phase in oil droplets, increasing the

power shaft in low ESP rotational speeds. In high rotational speeds, the shear rate and,

consequently, the turbulent energy are high enough to break the oil droplets without to

prejudice the ESP performance.


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2.6. Hysteresis in Phase Inversion Point

The analysis of hysteresis presence in the experiments was done starting the tests with

100% of water cut going to zero. Hysteresis is observed only for 800 rpm and 1200 rpm

at 52 cP. Thus, with low viscosity and low degree of agitation, the liquid-liquid mixture is

easier separated, changing the phase inversion point. This hysteresis also is influenced

by surface wettability and the initial arrangement of the phases. This phenomenon is

presented in Fig. 18 and 19.

For the rotation speeds of 800 rpm, 1200 rpm and 2400 rpm at 298cP and 2400 rpm at

52 cP hysteresis did not occur. In other words, high viscosity or high rotational speed

make the phases separation difficult leading to no hysteresis. More detailed studies are

necessary to exactly understands the factors that influence hysteresis in ESP.

3. CONCLUSION In this study an experimental analysis of the phase inversion phenomenon in electrical

submersible pumps under oil-water two-phase flows was performed. The influence of

oil viscosity in the phase inversion phenomenon was investigated. An 8-stage ESP was

tested with three different rotational speeds (800 rpm, 1200 rpm e 2400 rpm) and two

different oil viscosities (approximately 52 cP and 298 cP) for BEP flow rates. The oil

viscosity was controlled by changing its temperature.

The lift capacity and efficiency of centrifugal pumps are affected by viscosity [2]. This

fact can be observed in Fig. 3, 4, 5, 6, 7 and 8.


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In emulsions, the continuous phase directly influences the effective viscosity.

In this study, the experiments started with water cut equal to zero (oil single-phase

flow) and end with 100% water cut (water single-phase flow). For low water cuts, the

continuous phase is the oil and the head capacity and efficiency of the ESP is severely

affected, with high degradation. As water is added to the mixture the water cut

increases and the inversion phase takes place, so, the water becomes the continuous

phase and the head capacity and efficiency of the ESP is improved as shown in Fig. 9, 10,

11, 15, 16 and 17.

There are many studies of phase inversion phenomena in horizontal pipelines.

Reference [3] proposed a correlation based on oil and water viscosity to predict the

phase inversion point for horizontal pipes. The experimental data obtained in this study

was compared to the correlation presented by [3], and for low viscosity (52 cP) the

correlation showed small deviations from the ESP experimental data. For high viscosity

(298 cP), the correlation presented satisfactory results.

The hysteresis was observed in the ESP for 52 cP oil viscosity and rotating speeds of 800

rpm and 1200 rpm (Fig. 18 and 19), varying the phase inversion phase depending on the

initial condition (oil-to-water or water-to-oil). Thus, for low viscosity and low rotational

speed the phase separation process happens more easily. Other factors that may

influence this phenomenon are surface wettability and initial arrangement of the

phases. More detailed studies are needed to more exactly understand these and other

factors that affect the hysteresis in ESPs.

ACKNOWLEDGMENT


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The authors also thank Artificial Lift & Flow Assurance Research Group (ALFA), Center

for Petroleum Studies (CEPETRO), and School of Mechanical Engineering (FEM) all at the

University of Campinas (UNICAMP) in Brazil. The acknowledgements are extended to

FAPESP - Process 2017/15736-3 and CAPES - Finance Code 001.

FUNDING

The authors would like to thank Equinor Brazil, ANP (“Compromisso de Investimentos

com Pesquisa e Desenvolvimento”), and PRH/ANP for providing financial support for this

study.


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NOMENCLATURE

ESP electrical submersible pump

BEP best efficiency point

q flow rate at BEP, m³/s

m mean dimensionless head

dimensionless head per ESP stage

P differential pressure between ESP inlet and outlet, Pa

ESP rotating speed, rad/s

D ESP diameter, m

flow rate dimensionless

ESP efficiency

e emulsion density, kg/m³

o oil density, kg/m³

w water density, kg/m³

sW

staff potential, J/s

wf water cut

,w INVf phase inversion point

o oil viscosity, cP


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w water viscosity, cP


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REFERENCES (Samples of the most commonly referenced materials are provided. If in doubt, please refer to the latest editor of the Chicago Manual of Style. DOIs should be provided whenever possible for the greatest accuracy. [1] Kokal, S., 2005. “Crude-oil emulsions, a state-of-the-art review”. SPE 77497-PA. Production and Facilities. [2] Zhu, J., Banjar, H., Xia, Z. and Zhang, H.Q., “CFD simulation and experimental study of oil viscosity effect on multi-stage electrical submersible pump (ESP) performance”. Journal of Petroleum Science and Engineering, [s.l.], v. 146, p.735-745, out. 2016. [3] Arirachakaran, S., Oglesby, K. D., Malinawsky, M. S., Shoham, O. and Brill, J. P., 1989. “An analysis of oil/water flow phenomena in horizontal pipes”. SPE paper 18836. SPE Prof. Prod. Operating Symp., Oklahoma. [4] Ioannou, K., Hu, B., Matar, O. K., Hewitt, G. F. and Angeli, P. 2004, “Phase inversion in dispersed liquid-liquid pipe flows”, In Proceedings of the 5th International Conference on Multiphase Flow, Yokohama, Japan. [5] Ngan, K. H., Ioannou, K., Rhyne, L. D., Wang, W. and Angeli, P. “A methodology for predicting phase inversion during liquid–liquid dispersed pipeline flow”. Chemical Engineering Research and Design, [s.l.], v. 87, n. 3, p.318-324, mar. 2009. [6] Brinkman, H. C., 1952, “The viscosity of concentrated suspensions and solutions”. J Chem Phys, 20(4): 571. [7] Roscoe, R., 1952, “The viscosity suspensions of rigid spheres”. Br J Appl Phys, 3: 267-269. [8] Furuse, H., 1972, “Viscosity of concentrated solution”. Jpn J Appl Phys, 11(10): 1537-1541. [9] Pal, R., 2001, “Single-parameter and two-parameter rheological equations of state for nondilute emulsions”. Ind Eng Chem Res, 40: 5666-5674 [10] Yeh, G. C., Haynei, F. H., Jr. ande Moses, R. A., 1964, “Phase volume relationship at the point of phase inversion in liquid dispersions”. AIChE J, 10(2): 260-265 [11] Vieira, T. S., Siqueira, J. R., Bueno, A. D., Morales, R. E. M. and Estevam, V., “Analytical study of pressure losses and fluid viscosity effects on pump performance during monophase flow inside an ESP stage”. Journal of Petroleum Science and Engineering, [s.l.], v. 127, p.245-258, mar. 2015.


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[12] Pineda, H., Biazussi, J., López, F., Oliveira, B., Carvalho, R. D. M., Bannwart, A. C. and Ratkovich, N., “Phase distribution analysis in an Electrical Submersible Pump (ESP) inlet handling water–air two-phase flow using Computational Fluid Dynamics (CFD)”. Journal of Petroleum Science and Engineering, [s.l.], v. 139, p.49-61, mar. 2016.. [13] Guet, S., Rodriguez O. M. H., Oliemans R. V. A. and Brauner N. “An inverse dispersed multiphase flow model for liquid production rate determination”. International Journal of Multiphase Flow, [s.l.], v. 32, n. 5, p.553-567, maio 2006.


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Figure Captions List

Fig. 1 Experimental flow loop, the black box indicates the intersection where the

fluids are mixed before entering the ESP.

Fig. 2 Viscosity as a function of temperature.

Fig. 3 Comparison of dimensionless head as a function of dimensionless flow

rate between 52 cP, 298 cP and water for 800 rpm.





Fig. 6 Comparison of ESP efficiency as a function of dimensionless flow rate

between 52 cP, 298 cP and water for 800 rpm.





Fig. 9 Comparison of dimensionless head as a function of water cut between

298cP (BEP 7.65m³/h) and 52cP (BEP 10.78m³/h) for 800 rpm.


298cP (BEP 12.25m³/h) and 52cP (BEP 25.94m³/h) for 1200 rpm.


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298cP (BEP 26.94 m³/h) and 52cP (BEP 33.70 m³/h) for 2400 rpm.

Fig. 12 Comparison of dimensionless head as a function of water cut by ESP stage

at 298cP (BEP 26.94 m³/h) for 2400 rpm.

Fig. 13 Comparison of dimensionless head as a function of water cut between the

three rotating speeds (800 rpm, 1204 rpm and 2400 rpm) for the same

viscosity (298 cP) and model of [3].

Fig. 14 Comparison of dimensionless head as a function of water cut between the

three rotating speeds (800 rpm, 1200 rpm and 2400 rpm) for the same

viscosity (52 cP) and model of [3].

Fig. 15 Comparison of ESP efficiency as a function of water cut between two

viscosities (52 cP and 298 cP) for 800 rpm ESP rotating speed.





Fig. 18 Comparison of head as a function of water cut at 52 cP for 800 rpm ESP

rotating speed for two initial conditions (oil-to-water and water-to-oil).

Fig. 19 Comparison of head as a function of water cut at 52 cP for 1200 rpm ESP



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Table Caption List

Table 1 Matrix of experimental tests


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Table 1 - Matrix of experimental tests.

Oil viscosity [cP] Rotating speed [rpm] q [m³/h] [-]

298 ± 1

800 7.65 0.020

1200 12.25 0.022

2400 26.94 0.024

52 ± 1

800 10.78 0.028

1200 25.94 0.029

2400 33.70 0.030


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Figure 1. Experimental flow loop, the black box indicates the intersection where the

fluids are mixed before entering the ESP.


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Figure 2. Viscosity as a function of temperature.


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Figure 3. Comparison of dimensionless head as a function of dimensionless flow rate



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Figure 4. Comparison of dimensionless head as a function of dimensionless flow rate



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Figure 5 Comparison of dimensionless head as a function of dimensionless flow rate



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Figure 6. Comparison of ESP efficiency as a function of dimensionless flow rate between

52 cP, 298 cP and water for 800 rpm.


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31





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Figure 9. Comparison of dimensionless head as a function of water cut between 298cP

(BEP 7.65m³/h) and 52cP (BEP 10.78m³/h) for 800 rpm.


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(BEP 12.25m³/h) and 52cP (BEP 25.94m³/h) for 1200 rpm.


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(BEP 26.94 m³/h) and 52cP (BEP 33.70 m³/h) for 2400 rpm.


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Figure 12. Comparison of dimensionless head as a function of water cut by ESP stage at

298cP (BEP 26.94 m³/h) for 2400 rpm.


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Figure 13. Comparison of dimensionless head as a function of water cut between the three rotating speeds (800 rpm, 1204 rpm and 2400 rpm) for the same viscosity (298 cP) and model of Arirachakaran et al. (1989).


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Figure 14. Comparison of dimensionless head as a function of water cut between the

three rotating speeds (800 rpm, 1200 rpm and 2400 rpm) for the same viscosity (52 cP) and model of Arirachakaran et al. (1989).


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Figure 15. Comparison of ESP efficiency as a function of water cut between two



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Figure 18. Comparison of head as a function of water cut at 52 cP for 800 rpm ESP



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Figure 19. Comparison of head as a function of water cut at 52 cP for 1200 rpm ESP


experimental study of phase inversion phenomena in

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