AL_04_016_0 Schlumberger

April 2004 INCONEL is a trademark of Inco Alloys International, Inc.Poseidon is a mark of Institut Franais du Ptrole (IFP), Total, and Statoil; technology licensed to Schlumberger.

www.slb.com/oilfield

POSEIDON - Gas Handling Solutions for the Ultra High Gas ESP MarketThe Poseidon system is a multiphase,axial flow gas-handling device installedbelow the main production pump toallow the production pump to efficientlyhandle higher percentages of free gas.The system can be installed either abovea gas separator when gas can be ventedinto the casing, or it can be installedabove a standard intake if all theproduced gas has to go through thepump. In many wells with high gasvolume, the Poseidon system canincrease production and extend the useof submersible pumps in gassy oil wellswhere production is limited by thecentrifugal pumps ability to handle gas.Centrifugal pumps are mainly designed tohandle fluid and will suffer from a headdegradation and gas locking in thepresence of high percentages of free gas.The Poseidon gas handling system isdesigned to improve stability in gassywells, provide better slug handling inhorizontal wells, increase the productionrate and recovered reserves, andincrease electrical submersible pumpeffectiveness. It can also be used in wellswith nonvented packers typically foundin subsea and offshore completions.

System development Institut Francais du Petrole (IFP), Totaland Statoil, developed the Poseidon asthe next step in the historical evolutionof advanced gas handling. Understandingthe limitation of electrical submersiblepumps in gassy wells fields, Schlumbergeruses the Poseidon system to enhanceproduction in oil wells experiencing gaslocking problems.

Current gas handling systems rely oncentrifugal force to transfer energy tothe liquid/gas mixture. If there is a highpercentage of free gas in the vanes, theliquid and gas will separate and the energytransfer efficiency will decrease. Whenenough gas accumulates, the pump gaslocks and prevents fluid movement.The Poseidon gas handling system is amultiphase helicoaxial pump installedbetween the intake (or gas separator)and the pump. The specially designedaxial flow stages prime the mainproduction pump and push the gas -liquid flow stream into the stages. Gasvolume is reduced though the Poseidonby compression. Laboratory tests andfield trials have shown that the Poseidonsystem can successfully operate in theUltra high gas ESP market with gasvolume factors (GVF) up to 75%, farexceeding the 40 to 45% GVF limitationsof existing gas-handling devices.

Because of its special design, thePoseidon axial flow stage has a moreefficient energy transfer, resulting introuble-free operation at high GVF. ThePoseidon system maintains a highboosting pressure with increasingamounts of gas fraction and handles upto 75% free gas without experiencinggas locking.

Incremental oil production with a Poseidon system comparedwith oil production from conventional gas-handling equipment.

Variable speed drivesA variable speed drive (VSD) isrecommended as the surface controlpackage in all wells with high gasvolumes. A VSD provides pumpoperational flexibility with respect toflow rate and total dynamic headgeneration. Another key benefit is theability to control and manage the startupand initial production, enabling theoperator to limit gas slugging andmaintain completion integrity to preventsand production. The Schlumberger sinewave VSD combines a built-in filter withsuperior pulsed width modulationtechnology, providing near-sinusoidalcurrent and voltage waveforms to theESP motor.

Downhole monitoring In addition to a sine wave VSD, allsubmersible pumps for high gas-fractionenvironments should be equipped with adownhole monitoring tool. The primarymeans of equipment protection, amonitoring tool delivers valuableoperational and production data.Schlumberger offers multisensor toolsthat monitor pump intake and dischargepressures, wellbore temperature, internalmotor winding temperature, currentleakage, and vibration. Instead of shuttingdown from current underload control,multisensors allow the primaryprotection to be motor windingtemperature, providing the bestopportunity to ride through slugging gas conditions.

REDA Pump performance curve

System shutdown on winding temperature after prolonged gas slug.

Sine wave Variable Speed Drive

Time

OilProduction

Poseidon system

Conventionalgas handlingsystem

Gas Solutions Technology forSubmersible Pump Applications

Efficiently producehigh GOR wells withsubmersible pumps

Increases production of oil wells with high gas cut.

Gas can also be avoided by using aneccentric weighted outer sleeve toprovide a self-orientating intake with inletports at the lower side of the casingannulus. These intakes are designed forhighly deviated and horizontal wells. Thegas phase flows past the top of the deviceand the heavier liquid phase flows intothe inlet ports and into the pump or othergas-handling device. This system can alsobe installed below the ESP on a tailpipeconnected to a shroud.

Gas separationNatural gas separation occurs because ofthe differences in density and buoyancybetween the gas and the liquid phases.Many factors make estimation of naturalgas separation efficiency difficult.

Factors impacting natural andmechanical separation include casing andequipment size, free gas volumepercentage, pump intake pressure andtemperature, hydrocarbon composition,bubblepoint pressure, casing pressure,flow rate, obstructions and restrictions,and operating frequency.

Mechanical gas separatorsThese separators are either static ordynamic devices.

Static gas separators are designed tokeep free gas from entering the pumpwithout applying additional mechanicalforce. The basic principle of operation isprovision of a tortuous path requiring thefluid stream to turn and move downtoward the inlet ports. Some of the freegas accompanies the liquid to theintake, and a portion separates. Staticseparators are used for small amountsof free gas; their overall separationefficiency is limited.

Dynamic gas separators impart energyto the fluid to facilitate separation ofvapor from the liquid.

Vortex-style gas separators use anatural vortex action created by a specialinlet configuration, axial flow inducer,propeller, retention chamber, anddischarge crossover. These separatorsprovide efficiency over a broader flowrange than rotary separators.

Schlumberger vortex separators useabrasion-resistant bearing technologyto enhance reliability in sandy andabrasive conditions. To further extendlife expectancy, the separator impartsvery little energy to the solid particlesproduced through it.

These separators have a hydraulicdesign that uses advancedcomputational fluid dynamics andsolids modeling technology. Theimproved hydraulics enable moreeffective gas separation at higher fluidflow rates than previously possible.

Gas handling solutionsGas handling solutions for ESPoperations fall into two groups:centrifugal gas handlers for GVF to 45%at low intake pressures, and axial flowtechnology for GVF to 75%.

The Schlumberger Advanced GasHandler (AGH) improves the overall liftefficiency of a submergible liftinstallation by maintaining a highergas/liquid ratio in the tubing string. Thehigher GVF will reduce the hydraulichorsepower required to lift oil in a wellproducing oil, water, and gas.

The AGH centrifugal stage design altersthe pressure distribution of the impeller,creating a homogenized mixture with asmaller gas bubble. This conditioned fluidbehaves as a single-phase fluid beforeentering the pump.

Proven field results50% productionincreaseA well in Europe was plagued with gaslocking, and its production was limited to800 BPD [925 cf/STB gas/oil ratio]. AnAGH was installed, but all otherdownhole equipment remained the same.Production increased 1,250 BPD and thegas locking was eliminated. Free gasproduced through the pump was 23%. Inaddition to increased production,elimination of cycling extended theequipments expected run life.

Advanced Gas Handler

Vortex Gas Separator

Why is gas a problem?The application of ESPs has grownrapidly in recent years, often pushing thetechnology envelope for highertemperatures, pressures, abrasives, andgas content. Wells are routinely producedbelow bubblepoint pressure to maximizedrawdown and increase totalhydrocarbon production. The higherdrawdowns require the pumping systemto handle significant volumes of gas.And, with advances in gas handlingtechnology, wells with high gas volumes,once considered "too gassy" for ESPs, arenow being pumped successfully.

How does gas affect ESPs?Extreme differences in the densities ofliquids and gases create a low-pressurearea in the impeller eye, resulting in gasaccumulation. Free gas in the stageimpellers displaces liquid and restrictsthe volumetric efficiency of the pump.The accumulation of free gas results inlower lift per stage and a decline inexpected production.

Without technology to preventexcessive gas accumulation, either gasinterference or gas lock will occur.

Gas interference is a partial blockageof the impeller flow path, resulting indegraded pump performance and lowproduction. Gas lock is completeblockage of the flow path and requires ashutdown of the pump. Gas and gas lockcan be detected by pressure fluctuationsmeasured by a downhole sensor or byerratic current fluctuations from an ampchart.

Approaches to minimize gas effectsThere are three basic methods to minimizethe amount of gas entering the pump: gasavoidance, gas separation, and gashandling.

Gas avoidanceShrouded systems placed belowperforations enhance natural separationand reduce free gas at the pump. Thesesystems usually require smaller-diameter ESP systems and may limitproduction.

Shrouded submersible pump

Applications Oil-producing wells with high

gas cut

Oil-producing wells with nonvented packers

Gas lift for wells converted toelectrical submersible pumps (ESPs)

Dual-liftgas lift and ESP wells

Subsea oil wells

Benefits Improved production and field

life from maximized drawdown

Fewer shutdowns due to gas locks

Extended pump run life

Longer installation run life withstabilized motor current

Features Vortex gas separators capable

of greater than 90% separationefficiency

Centrifugal gas handlerscapable of intake gas volumefraction (GVF) of 45% at lowpump intake pressures

Poseidon multiphase pumpsystems capable of intake GVF of 75%

Abrasion-resistant construction

Ammeter chart depicting gas interference

Gas Interference

Gas Lock Shutdown

Perforations

Shrouded ESP

Monday

Tuesday

WednesdayThursd

ay

Frid

aySa

turda

y

Sunday

AL_04_016_0 Schlumberger

April 2004 INCONEL is a trademark of Inco Alloys International, Inc.Poseidon is a mark of Institut Franais du Ptrole (IFP), Total, and Statoil; technology licensed to Schlumberger.

www.slb.com/oilfield

POSEIDON - Gas Handling Solutions for the Ultra High Gas ESP MarketThe Poseidon system is a multiphase,axial flow gas-handling device installedbelow the main production pump toallow the production pump to efficientlyhandle higher percentages of free gas.The system can be installed either abovea gas separator when gas can be ventedinto the casing, or it can be installedabove a standard intake if all theproduced gas has to go through thepump. In many wells with high gasvolume, the Poseidon system canincrease production and extend the useof submersible pumps in gassy oil wellswhere production is limited by thecentrifugal pumps ability to handle gas.Centrifugal pumps are mainly designed tohandle fluid and will suffer from a headdegradation and gas locking in thepresence of high percentages of free gas.The Poseidon gas handling system isdesigned to improve stability in gassywells, provide better slug handling inhorizontal wells, increase the productionrate and recovered reserves, andincrease electrical submersible pumpeffectiveness. It can also be used in wellswith nonvented packers typically foundin subsea and offshore completions.

System development Institut Francais du Petrole (IFP), Totaland Statoil, developed the Poseidon asthe next step in the historical evolutionof advanced gas handling. Understandingthe limitation of electrical submersiblepumps in gassy wells fields, Schlumbergeruses the Poseidon system to enhanceproduction in oil wells experiencing gaslocking problems.

Current gas handling systems rely oncentrifugal force to transfer energy tothe liquid/gas mixture. If there is a highpercentage of free gas in the vanes, theliquid and gas will separate and the energytransfer efficiency will decrease. Whenenough gas accumulates, the pump gaslocks and prevents fluid movement.The Poseidon gas handling system is amultiphase helicoaxial pump installedbetween the intake (or gas separator)and the pump. The specially designedaxial flow stages prime the mainproduction pump and push the gas -liquid flow stream into the stages. Gasvolume is reduced though the Poseidonby compression. Laboratory tests andfield trials have shown that the Poseidonsystem can successfully operate in theUltra high gas ESP market with gasvolume factors (GVF) up to 75%, farexceeding the 40 to 45% GVF limitationsof existing gas-handling devices.

Because of its special design, thePoseidon axial flow stage has a moreefficient energy transfer, resulting introuble-free operation at high GVF. ThePoseidon system maintains a highboosting pressure with increasingamounts of gas fraction and handles upto 75% free gas without experiencinggas locking.

Incremental oil production with a Poseidon system comparedwith oil production from conventional gas-handling equipment.

Variable speed drivesA variable speed drive (VSD) isrecommended as the surface controlpackage in all wells with high gasvolumes. A VSD provides pumpoperational flexibility with respect toflow rate and total dynamic headgeneration. Another key benefit is theability to control and manage the startupand initial production, enabling theoperator to limit gas slugging andmaintain completion integrity to preventsand production. The Schlumberger sinewave VSD combines a built-in filter withsuperior pulsed width modulationtechnology, providing near-sinusoidalcurrent and voltage waveforms to theESP motor.

Downhole monitoring In addition to a sine wave VSD, allsubmersible pumps for high gas-fractionenvironments should be equipped with adownhole monitoring tool. The primarymeans of equipment protection, amonitoring tool delivers valuableoperational and production data.Schlumberger offers multisensor toolsthat monitor pump intake and dischargepressures, wellbore temperature, internalmotor winding temperature, currentleakage, and vibration. Instead of shuttingdown from current underload control,multisensors allow the primaryprotection to be motor windingtemperature, providing the bestopportunity to ride through slugging gas conditions.

REDA Pump performance curve

System shutdown on winding temperature after prolonged gas slug.

Sine wave Variable Speed Drive

Time

OilProduction

Poseidon system

Conventionalgas handlingsystem

Gas Solutions Technology forSubmersible Pump Applications

Efficiently producehigh GOR wells withsubmersible pumps

Increases production of oil wells with high gas cut.

Gas can also be avoided by using aneccentric weighted outer sleeve toprovide a self-orientating intake with inletports at the lower side of the casingannulus. These intakes are designed forhighly deviated and horizontal wells. Thegas phase flows past the top of the deviceand the heavier liquid phase flows intothe inlet ports and into the pump or othergas-handling device. This system can alsobe installed below the ESP on a tailpipeconnected to a shroud.

Gas separationNatural gas separation occurs because ofthe differences in density and buoyancybetween the gas and the liquid phases.Many factors make estimation of naturalgas separation efficiency difficult.

Factors impacting natural andmechanical separation include casing andequipment size, free gas volumepercentage, pump intake pressure andtemperature, hydrocarbon composition,bubblepoint pressure, casing pressure,flow rate, obstructions and restrictions,and operating frequency.

Mechanical gas separatorsThese separators are either static ordynamic devices.

Static gas separators are designed tokeep free gas from entering the pumpwithout applying additional mechanicalforce. The basic principle of operation isprovision of a tortuous path requiring thefluid stream to turn and move downtoward the inlet ports. Some of the freegas accompanies the liquid to theintake, and a portion separates. Staticseparators are used for small amountsof free gas; their overall separationefficiency is limited.

Dynamic gas separators impart energyto the fluid to facilitate separation ofvapor from the liquid.

Vortex-style gas separators use anatural vortex action created by a specialinlet configuration, axial flow inducer,propeller, retention chamber, anddischarge crossover. These separatorsprovide efficiency over a broader flowrange than rotary separators.

Schlumberger vortex separators useabrasion-resistant bearing technologyto enhance reliability in sandy andabrasive conditions. To further extendlife expectancy, the separator impartsvery little energy to the solid particlesproduced through it.

These separators have a hydraulicdesign that uses advancedcomputational fluid dynamics andsolids modeling technology. Theimproved hydraulics enable moreeffective gas separation at higher fluidflow rates than previously possible.

Gas handling solutionsGas handling solutions for ESPoperations fall into two groups:centrifugal gas handlers for GVF to 45%at low intake pressures, and axial flowtechnology for GVF to 75%.

The Schlumberger Advanced GasHandler (AGH) improves the overall liftefficiency of a submergible liftinstallation by maintaining a highergas/liquid ratio in the tubing string. Thehigher GVF will reduce the hydraulichorsepower required to lift oil in a wellproducing oil, water, and gas.

The AGH centrifugal stage design altersthe pressure distribution of the impeller,creating a homogenized mixture with asmaller gas bubble. This conditioned fluidbehaves as a single-phase fluid beforeentering the pump.

Proven field results50% productionincreaseA well in Europe was plagued with gaslocking, and its production was limited to800 BPD [925 cf/STB gas/oil ratio]. AnAGH was installed, but all otherdownhole equipment remained the same.Production increased 1,250 BPD and thegas locking was eliminated. Free gasproduced through the pump was 23%. Inaddition to increased production,elimination of cycling extended theequipments expected run life.

Advanced Gas Handler

Vortex Gas Separator

Why is gas a problem?The application of ESPs has grownrapidly in recent years, often pushing thetechnology envelope for highertemperatures, pressures, abrasives, andgas content. Wells are routinely producedbelow bubblepoint pressure to maximizedrawdown and increase totalhydrocarbon production. The higherdrawdowns require the pumping systemto handle significant volumes of gas.And, with advances in gas handlingtechnology, wells with high gas volumes,once considered "too gassy" for ESPs, arenow being pumped successfully.

How does gas affect ESPs?Extreme differences in the densities ofliquids and gases create a low-pressurearea in the impeller eye, resulting in gasaccumulation. Free gas in the stageimpellers displaces liquid and restrictsthe volumetric efficiency of the pump.The accumulation of free gas results inlower lift per stage and a decline inexpected production.

Without technology to preventexcessive gas accumulation, either gasinterference or gas lock will occur.

Gas interference is a partial blockageof the impeller flow path, resulting indegraded pump performance and lowproduction. Gas lock is completeblockage of the flow path and requires ashutdown of the pump. Gas and gas lockcan be detected by pressure fluctuationsmeasured by a downhole sensor or byerratic current fluctuations from an ampchart.

Approaches to minimize gas effectsThere are three basic methods to minimizethe amount of gas entering the pump: gasavoidance, gas separation, and gashandling.

Gas avoidanceShrouded systems placed belowperforations enhance natural separationand reduce free gas at the pump. Thesesystems usually require smaller-diameter ESP systems and may limitproduction.

Shrouded submersible pump

Applications Oil-producing wells with high

gas cut

Oil-producing wells with nonvented packers

Gas lift for wells converted toelectrical submersible pumps (ESPs)

Dual-liftgas lift and ESP wells

Subsea oil wells

Benefits Improved production and field

life from maximized drawdown

Fewer shutdowns due to gas locks

Extended pump run life

Longer installation run life withstabilized motor current

Features Vortex gas separators capable

of greater than 90% separationefficiency

Centrifugal gas handlerscapable of intake gas volumefraction (GVF) of 45% at lowpump intake pressures

Poseidon multiphase pumpsystems capable of intake GVF of 75%

Abrasion-resistant construction

Ammeter chart depicting gas interference

Gas Interference

Gas Lock Shutdown

Perforations

Shrouded ESP

Monday

Tuesday

WednesdayThursd

ay

Frid

aySa

turda

y

Sunday

AL_04_016_0 Schlumberger

April 2004 INCONEL is a trademark of Inco Alloys International, Inc.Poseidon is a mark of Institut Franais du Ptrole (IFP), Total, and Statoil; technology licensed to Schlumberger.

www.slb.com/oilfield

POSEIDON - Gas Handling Solutions for the Ultra High Gas ESP MarketThe Poseidon system is a multiphase,axial flow gas-handling device installedbelow the main production pump toallow the production pump to efficientlyhandle higher percentages of free gas.The system can be installed either abovea gas separator when gas can be ventedinto the casing, or it can be installedabove a standard intake if all theproduced gas has to go through thepump. In many wells with high gasvolume, the Poseidon system canincrease production and extend the useof submersible pumps in gassy oil wellswhere production is limited by thecentrifugal pumps ability to handle gas.Centrifugal pumps are mainly designed tohandle fluid and will suffer from a headdegradation and gas locking in thepresence of high percentages of free gas.The Poseidon gas handling system isdesigned to improve stability in gassywells, provide better slug handling inhorizontal wells, increase the productionrate and recovered reserves, andincrease electrical submersible pumpeffectiveness. It can also be used in wellswith nonvented packers typically foundin subsea and offshore completions.

System development Institut Francais du Petrole (IFP), Totaland Statoil, developed the Poseidon asthe next step in the historical evolutionof advanced gas handling. Understandingthe limitation of electrical submersiblepumps in gassy wells fields, Schlumbergeruses the Poseidon system to enhanceproduction in oil wells experiencing gaslocking problems.

Current gas handling systems rely oncentrifugal force to transfer energy tothe liquid/gas mixture. If there is a highpercentage of free gas in the vanes, theliquid and gas will separate and the energytransfer efficiency will decrease. Whenenough gas accumulates, the pump gaslocks and prevents fluid movement.The Poseidon gas handling system is amultiphase helicoaxial pump installedbetween the intake (or gas separator)and the pump. The specially designedaxial flow stages prime the mainproduction pump and push the gas -liquid flow stream into the stages. Gasvolume is reduced though the Poseidonby compression. Laboratory tests andfield trials have shown that the Poseidonsystem can successfully operate in theUltra high gas ESP market with gasvolume factors (GVF) up to 75%, farexceeding the 40 to 45% GVF limitationsof existing gas-handling devices.

Because of its special design, thePoseidon axial flow stage has a moreefficient energy transfer, resulting introuble-free operation at high GVF. ThePoseidon system maintains a highboosting pressure with increasingamounts of gas fraction and handles upto 75% free gas without experiencinggas locking.

Incremental oil production with a Poseidon system comparedwith oil production from conventional gas-handling equipment.

Variable speed drivesA variable speed drive (VSD) isrecommended as the surface controlpackage in all wells with high gasvolumes. A VSD provides pumpoperational flexibility with respect toflow rate and total dynamic headgeneration. Another key benefit is theability to control and manage the startupand initial production, enabling theoperator to limit gas slugging andmaintain completion integrity to preventsand production. The Schlumberger sinewave VSD combines a built-in filter withsuperior pulsed width modulationtechnology, providing near-sinusoidalcurrent and voltage waveforms to theESP motor.

Downhole monitoring In addition to a sine wave VSD, allsubmersible pumps for high gas-fractionenvironments should be equipped with adownhole monitoring tool. The primarymeans of equipment protection, amonitoring tool delivers valuableoperational and production data.Schlumberger offers multisensor toolsthat monitor pump intake and dischargepressures, wellbore temperature, internalmotor winding temperature, currentleakage, and vibration. Instead of shuttingdown from current underload control,multisensors allow the primaryprotection to be motor windingtemperature, providing the bestopportunity to ride through slugging gas conditions.

REDA Pump performance curve

System shutdown on winding temperature after prolonged gas slug.

Sine wave Variable Speed Drive

Time

OilProduction

Poseidon system

Conventionalgas handlingsystem

Gas Solutions Technology forSubmersible Pump Applications

Efficiently producehigh GOR wells withsubmersible pumps

Increases production of oil wells with high gas cut.