ESP Performance
19
Experimental studies of ESP performance with live viscous oil Alexey Pavlov and Bente Helgeland Sannæs Classification: Internal 2012-07-02
description
esp failure
Transcript of ESP Performance
Experimental studies of ESP performance with live viscous oil Alexey Pavlov and Bente Helgeland Sannæs
Classification: Internal 2012-07-02
Outline
• Background and motivation
• The experimental facility
• Performance analysis
• Results
• Conclusions
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Background
• Viscous crudes: challenging production
• Artificial lift is often needed ESP
• Increased use of ESPs in Statoil
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Well
Production
choke
Reservoir
pump Pressure
increase
Electrical Submersible Pump (ESP)
• Multistage centrifugal pump – efficient means of artificial lift
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ESP
Well
Production
choke
Reservoir
pump Pressure
increase
Background
• Selection of ESPs in development projects requires
− Reliable data on ESP performance
• Two-way effect: ESP Flow
• Multiphase flow with viscous oils (emulsions?)
• Water- or oil continuous flows?
• Challenges
− Lack of reliable ESP models for viscous fluids
− Lack of reliable correlations for multiphase fluids
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Well
Production
choke
Reservoir
pump Pressure
increase
Background
• Correct and optimal selection of ESPs requires
− Reliable data on ESP performance
• Two-way effect: ESP Flow
• Multiphase flow with viscous oils (emulsions?)
• Water- or oil continuous flows?
• Challenges
− Lack of reliable ESP models for viscous fluids
− Lack of reliable correlations for multiphase fluids
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Solution: Get ESP performance data from lab experiments:
- live viscous oils
- full scale pump
- wide range of operating conditions
(flow-rate, pressure, temperature, WC,
GOR, ESP frequency)
- advanced instrumentation
Experimental facility - overview
• Main separator
• Feeding pumps
• Heat exchangers
• ESP
• Flow loop
• Cold separation
• Hot separation
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Experimental facility
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• Multiphase flow-loop in Statoil research center, Porsgrunn, Norway
− Operational since 1995
− 2011: upgraded to include ESP and to handle viscous oils
ESP section
ESP instrumentation
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Entering water
• Mass flow rate
• Temperature
Pump entrance
• Mixture temperature
• Pressure
Pump discharge
• Temperature
• Pressure
ESP (VSD)
• Speed
• Torque
• Power
• Current
Entering oil
• Water content
• Mass flow rate
• Temperature
ESP performance analysis
• Characterized by Head, Power, and Efficiency
• ESP performance for water: good models from pump vendors
• Affected by fluid viscosity
− high viscosity low head, high power, low efficiency
− ESP model: Viscosity Correction Factors
• Our study: two-phase flows (oil-water)
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Well
pump Pressure
increase
Effective viscosity
• Fluid evolution through the ESP
− Pressure increase
− Temperature increase
− Mixing of phases
viscosity changes throughout the ESP
• Effective viscosity
− Overall viscosity experienced by ESP
− Solely reflects an effect of fluid on ESP performance
− Convenient to compare it to oil phase viscosity
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Inversion point – function of water cut
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Fixed oil viscosity, varying WC
Inversion point
Oil continuous
Water
continuous
Inversion point: effect of WC and oil viscosity
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Oil continuous
Water
continuous
Inversion point
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Inversion point: effect of WC and oil viscosity
Smooth transition from oil-continuous to
water continuous regimes
Emulsions
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The most extreme emulsions:
relatively low oil viscosity and relatively high WC
Frequency effects
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Fixed oil viscosity and WC, varying ESP frequency:
Different properties for oil- and water continuous cases
Conclusions
• Statoil’s multiphase flow loop facility:
− Unique opportunity to study ESP performance with a “magnifying glass”
• Novel results on ESP performance for two-phase viscous fluids
• Invaluable data for development projects
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Acknowledgements
• We would like to thank our fellow researchers, the flow loop technicians and all our
other colleagues working with the multiphase flow loop in Porsgrunn.
• We would also like to thank Statoil for the opportunity to publish the results.
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Experimental studies of ESP
performance with live viscous oil
Alexey Pavlov & Bente Helgeland Sannæs
[email protected] www.statoil.com
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