Wellheads

1. Tubing (perforated)2. Casing3. Annular seal4. Wellhead5. Tubing suspension6. Master valve7. Master valve8. Upper valve9. Wing valve10. Flow bean11. To manifold12. Operator13. Hand wheel14. Pressure gage15. Annular space outlet valve16. Cellar

Sumur Produksi

Penyelesaian sumur meliputi pemasangan casing dan rangkaian pipa produksi, serta mengupayakan agar cairan dapat mengalir ke permukaan, dimana dipasang kepala sumur lengkap dengan Christmas tree. Christmas tree merupakan sekumpulan valve, alat ukur tekanan, penyangga tubing, dll.

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What is a wellhead ?

– The wellhead is • the surface foundation on which the well is built up during

the drilling operations and • the base for the Xmas tree for production operations.

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Wellheads - DrillingDuring drilling process :

The well is controlled by a BOP and choke manifold

As the well is drilled :Each annulus is sealed off by the wellhead

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Wellheads - Completed well

Xmas Tree The BOP's are removed

After the tubing is installed :

The Christmas tree is installed to control the flow from the well

Wellhead

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Wellhead systems must be designed to :

Withstand tensile loads of suspended tubulars

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2 Provide a pressure sealing capabilityISOLATE the well from the external environment

ISOLATE between casings and downhole formations

MAINTAIN PRESSURE during well control operations, well testing or shut in periods.

Life of Well•Drilling•Production•Workover•Suspension•Abandonment

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What does a wellhead do ?

HANG-OFF WEIGHT1

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CONTAINS PRESSURE

MONITOR THE WELL SAFETY

PROVIDE A BASE FOR THE XMAS TREE

Surface Wellheads

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Conventional spooled system

Casing Head Housing

Casing Head Spool

Tubing Head Spool

BOP Stack

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What are the main components ?

Casing Head Housing

Casing Head Spool

Tubing Head Spool

Xmas Tree

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Surface Wellhead schematic• Medium cost spool system

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Casing Head HousingFirst element of the wellhead

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Casing Head Housing - Functions– It is normally connected to the surface casing– Supports the next string of casing– Provides connection to the BOP and together with it can:

• Seal the wellbore (from the atmosphere)• Control access to the wellbore :

– for pressure control – or fluid returns during drilling operations.

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Casing Head Housing - Description

Slip-on weld or threadedbottom connection

Test port

Side outlets threaded or studded

Top connection flanged (standard)

Ring groove

Landing area forCasing Hanger

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Starter Head• Threaded onto surface

casing• Can provide a landing plate

to sit on the conductor• Internal profile for next

casing string

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CHH - Base PlateThe casing head may be used in

conjunction with a base plate for more effective weight distribution.

Conductor pipe Surface casing

Cellar

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What happens after installing the Casing Head Housing ?

– Nipple up and test BOPs– Install wear bushing.– The next hole section is drilled. – The intermediate casing is run in the hole and is cemented.– P/U BOPs – A rough cut is performed to allow retrieving remaining casing and

removing BOPs

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Casing hung on Casing Hanger Housing

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Casing Hangers - Functions• Suspends intermediate or production casing string

• Centres the casing string in the head (or spool)

• Seals off the casing annulus. ( It is the primary seal )

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Starter Head summary

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Casing Hangers

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Casing Hangers

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Casing Hangers

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Casing Hangers

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Casing Head SpoolsSecond element of the wellhead

Normally not threaded as pressures higherEg >3000psi.

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Next Section is InstalledCasing Spool

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Casing Head Spools - Functions– Seals off (packs off) surface casing string– Provides support (landing bowl) for next casing string– Provides support for well control equipment (BOP Stack)

• Sealing the wellbore (from the atmosphere)• Controlling access to the wellbore :

– for pressure control – or fluid returns during drilling operations.

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Casing Head Spools - Description

Pack Off or Secondary Seal. Designed to fit around OD of current casing

Test port

Side outlets threaded or studded / flanged (threaded not common)

Top connection flanged (standard)Ring groove

Landing area forCasing Hanger

Bottom connectioncompatible with the top connection on theprevious casing head or spool

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What Seals Pressure Between Flanges ?

Achieved using API ring gaskets

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What happens after installing the Casing Spool Housing ?

– Nipple up and test BOPs– Install wear bushing.– The next hole section is drilled. – The intermediate/Production casing is run in the hole and is cemented.– P/U BOPs – A rough cut is performed to allow retrieving remaining casing and

removing BOPs.– Casing Hanger is installed

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Casing Hangers

Intermediateor

Production Casing

Landing area

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Casing Pack-offs• Fits inside the lower flange

of the casing spool

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Casing Pack-offs• Fits inside the lower flange

of the casing spool

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Casing Pack-offs• Fits inside the lower flange

of the casing spool

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Casing Spools summary

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Tubing Head SpoolsThird element of the wellhead

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Tubing Head Spools - Functions• Seals off (packs off) production casing string

• Provides support and lockdown for tubing hanger

• Provides support for the BOP Stack

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Tubing Head Spools - Description TUBING HANGER

LOCK DOWN BOLT

TOP BOWL FORTUBING HANGER

VALVE REMOVALPLUG THREADS

TEST PORT

Pack off designed to fit around OD of production casing

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Tubing Hangers

Tubing

Production casing

Tubing Head Spool

Tubing Hanger

Tubing Hanger

Tubing Head Spool

Tubing Bonnet

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Tubing Hangers

Functions • Suspends the tubing• Seals off the annulus• Provides a seat for a back pressure valve (BPV)

that can be temporally installed allowing the BOP stack or X-mas tree to be removed

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Dual Tubing Head• Locator pins to orient the

dual hanger

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Tubing Hanger

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Tubing Heads summary

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Tubing Bonnet• Seats over the tubing hanger

neck• Xmas tree on top of this

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Tubing Bonnet

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Tubing Bonnet

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Dual Tubing Bonnet• Dual completion• Two tubing strings

– Long string– Short string

• Spreader

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Tubing Bonnet summary

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Questions