Subsea HPUsSubsea HPUs

Contribution to reduced cost for injection X-mas trees

Svein Lilleland, FMC TechnologiesPer Ragnar Dahl StatoilHydroPer Ragnar Dahl, StatoilHydro

Presentation overwiewPresentation overwiew

• A historic review of subsea HPUs• A historic review of subsea HPUs

• Development of a subsea HPU to power injection XTsDevelopment of a subsea HPU to power injection XTs

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A historic review of subsea HPUs:A historic review of subsea HPUs:

• Hydraulicontrol; Subpack - 1972y ; p• NTNF-K; ”Snurre” RCV (ROV) – 1973 - 1978• Myrens Verksted Controlled Lifting Hook• Kvaerner underwater excavator• Mølleroddens Verksted; ”Check Mate” - 1977• SAAB Scania; SAAB Sub – 1978• Myrens Verksted; ”Snurre-III” ROV -1982

D V C1A j t• DnV C1A project• KOS / Technomare XT with subsea HPU - 1987• KOS Subsea HPU – 1993 - 1994• KOS Subsea HPU – 1993 - 1994

Those highlighted will be presented in more detail..

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Hydraulicontrol; SubpackHydraulicontrol; Subpack

Subsea HPU, designed to power diver operated underwater hydraulic tools.

Was in use by a number of divingWas in use by a number of diving operators.

Vickers PVB pressure controlled pump with externally controlled stroke.stroke.Commercial squirrel cage 3-Φmotor, modified for subsea use.

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IKU ”Snurre”IKU Snurre

Developed by NTNF-K (IKU)Brain child of Dr.Ing. Bo BrännströmProject mgr.: Arnfinn Lindstadj gElectronics: SI in OsloHydraulics: HydraulicontrolAssembly and test: Hydraulicontrol

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IKU ”Snurre”IKU Snurre

Ringerikes Blad 1975:

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Blad, 1975:

A side glance; Snurre development, the helmet controlled ROV

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NUI Check MateNUI Check Mate

D l d b M ll dd V k dDeveloped by Mølleroddens VerkstedProject mgr.: Tor LindheimOperated by: NUI (NUTEC)Pil t Vid F d ikPilot: Vidar FondevikHydraulics: Hydraulicontrol

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NUI Check MateNUI Check Mate

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SAAB SubSAAB Sub

Developed by: SAAB Scania (Aerospace) in Linköping(Aerospace) in Linköping.Project mgr.: Göran AlsebyHydraulics: Hydraulicontrol

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Myrens Verksted: Snurre and Snurre 2 1Myrens Verksted: Snurre and Snurre 2.1

• Developed by Myrens Verksted in Oslo• Developed by Myrens Verksted in Oslo

• Project mgr. Snurre: Kjell Nilsson

P j t S 2 1 P Ol f T• Project mgr. Snurre 2.1: Per Olaf Tangen

• Hydraulics: Hydraulicontrol

• Known customer for Snurre 2.1: Intersub Services SA (Marseilles)

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KOS / Technomare XTKOS / Technomare XT

•Developed by KOS and Technomare

Subsea XT with subsea HPU

•KOS project mgr.: Bjørn Quistgaard•Technomare project mgr.: Gianfranco Gobbo•Installed in July / August 1987•Commissioned in January 1988•”6 years of reliable operation” in 1994• 6 years of reliable operation in 1994•Current status unknown

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KOS HPU

Developed by Statoil and KOS

KOS project mgr.: Kjell StensrudKOS project mgr.: Kjell Stensrud

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Development of a subsea HPU to power injection XTs; the FMC eSHPUinjection XTs; the FMC eSHPU

StatoilHydro project mgr.: Per Ragnar DahlFMC project mgr : Peter Bergsland

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FMC project mgr.: Peter Bergsland

Development of a subsea HPU to power injection XTsXTs

The CAPEX motivation:The CAPEX motivation:

1. Five-well field using conventional electrohydraulic umbilical

2 Same field using only electric cable and subsea HPUs2. Same field using only electric cable and subsea HPUs

Hardware + Engineering

Umbilical + installation costg g

Case 1 MNOK 515 MNOK 191Case 1 MNOK 515 MNOK 191

Case 2 MNOK 438 MNOK 18Case 2 MNOK 438 MNOK 18

C fi FMC i t l ti t

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Capex figures are FMC internal estimates.

Development of a subsea HPU to power injection XTsXTs

• Hydraulic circuit diagram

• Main components

• Drive options

• LP-pumps

• HP GenerationHP Generation

• The rotary shaft seal challenge

• Replenishment of control fluid• Replenishment of control fluid

• Reservoir sizing

S ifi ti• Specifications

• Energy balance

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Development of a subsea HPU to power injection XTsXTs

Hydraulic circuit diagram

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Main components of the eSHPUMain components of the eSHPU

• Electronic cans with batteries, charger circuit, motor control d CAN band CAN-bus

• Motor and pump compartment

• HP Intensifier

• Pressurized reservoir* (Active Receiver)( )

• Hydraulic filter

Jumper*• Jumper*

• Water separator *

• Mounting base

* Not inside SCM-sized outer can

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Not inside SCM sized outer can

Drive options:Drive options:

• “Unter Oel” squirrel cage motor and DC/AC converter and• Unter Oel squirrel cage motor and DC/AC converter and batteries (Ziehl-Abegg, IKM)

• Submersible motor (Franklin), with DC/AC converter andSubmersible motor (Franklin), with DC/AC converter and batteries

• FMC eTech drive train with syncron motor and batteriesFMC eTech drive train with syncron motor and batteries

FMC eTech driveFMC eTech drive train selected. Field proven, and at an advanced stage of development

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development.

LP pumpsLP pumps

• Dynex Rivett “check ball” pump – basic but rugged

• Marshalsea subsea pump (for water-glycol)

• Bieri radial piston pump (for water-glycol) in testBieri radial piston pump (for water glycol) in test

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HP generationHP generation

• High pressure intensifier –High pressure intensifier Good record of reliability from Vigdis Extension

• Separate motor driven HP pump – expensive

Split flow pump no track• Split flow pump – no track record with split flow pumps

Marshallsea high pressure intensifier selected basedintensifier selected based

on Vigdis experience

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The rotary shaft seal challengeThe rotary shaft seal challenge

• Process industry type rotary seals, used extensively in early Hydraulicontrol projectsy p j

• Contain the pump and motor in a pressure compartment, virtually no differential pressure over the shaft seal

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The rotary shaft seal challengeThe rotary shaft seal challenge

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Replenishment of control fluidReplenishment of control fluid

• Supply hose from platform based HPU

• Retrievable reservoir ROV transported• Retrievable reservoir – ROV transported

• Pre charged and filled accumulator – ROV transported –connects via single line coupler – see circuit diagramconnects via single line coupler – see circuit diagram

Pre charged and filled accumulator currently selected

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Reservoir sizing:Reservoir sizing:

The FMC Active ReceiverThe FMC Active Receiver

• Active Receiver volume: 25 liters

• Pressure ratio: 20 : 1

• RET pressure @ 207 bar(g): ple

only

. at

ion

• RET pressure @ 207 bar(g): 10.3 bar(g)

• Pressurized reservoir: 25 liters how

n as

prin

cip

s fro

m th

e ill

ustra

• Pressurized reservoir: 25 liters

• Pressure ratio: 19 : 1

ve R

ecei

ver i

s s

al d

esig

n di

ffers

• RET pressure @ 207 bar(g) LP: 10.8 bar, and at 345 bar(g); 18 bar(g)

The

Act

ivTh

e ac

tua

25

bar(g)

Reservoir and reservoir sizingReservoir and reservoir sizing

Sizing considerations:Sizing considerations:

• Accumulator charge and discharge volume

E t l l k t (DHSV)• External leak rate (DHSV)

• Temperature contraction

• Fluid compression

• Air inclusions

• Actuator rod imbalance

External leak rates will be carefully scrutinized

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te a ea ates be ca e u y sc ut ed

Reservoir and reservoir sizingReservoir and reservoir sizing

Two Active Receivers provides a reservoir capacity ofTwo Active Receivers provides a reservoir capacity of 50 liters, one on the XMT, the second on the ISS

The Active Receiver (Pressurized reservoir) on the eSHPU is level instrumented.

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Specification – 1: HydraulicSpecification – 1: Hydraulic

• eSHPU shall connect to XMT via logic cap on XT• eSHPU shall connect to XMT via logic cap on XT

• Control fluid as standard for Hydro (Brayco SV/B)

LP l 207 b ( )• LP supply: 207 bar(g)

• HP supply: <690 bar(g)

• Return pressure: 10 bar(g) (Nominal)

• Design pressure return: 40 bar(g)g p (g)

• Hydraulic cleanliness: AS4059 class 6B-F, 20% Rh

• Total air inclusion: < 2 normal liters• Total air inclusion: < 2 normal liters

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Draft specifications – 2: ElectricDraft specifications – 2: Electric

• Battery capacity: 5 4 * 106 Joules• Battery capacity: 5.4 10 Joules

• Requirement 1: Capacity to open well 6 times in sequence

R i t 2 2 h t h ft 1 ll• Requirement 2: < 2 hours to recharge after 1 well open sequence

C t l F SCM i j d CAN b• Control: From SCM via jumper and CAN-bus

• Charging: 24 VDC nominal

• Charging power: 100 watts

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Energy balance:Energy balance:

• Energy to open a well @ 207 bar≈ 300 000 joulesEnergy to open a well @ 207 bar≈ 300 000 joules

• Energy in fully charged battery ≈ 5.4 * 106 joules

A d ffi i ( lifi d ti ) 50 %• Assumed efficiency (qualified assumption): 50 %

• Requirement 1: 9 well open sequences

• Requirement 2: 1.5 hours

• Internal leakage SCM max. (From Vigdis Study): 3 wattg ( g y)– 4.3 cc/min @ 350 bar and 50% efficiency

• The pump will recharge accumulator every 2 6 hours• The pump will recharge accumulator every 2.6 hours– Pin=325(barg), Pout=345(barg), Precharge 200 bar, Vol 20L, net 0.68L

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Conclusion:

The project is feasible and will be implementedThe project is feasible and will be implemented.

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