Wellhead for oil and gas well

Wellheads

Sumur Produksi

1. Tubing (perforated) 2. Casing 3. Annular seal 4. Wellhead 5. Tubing suspension 6. Master valve 7. Master valve 8. Upper valve 9. Wing valve 10. Flow bean 11. To manifold 12. Operator 13. Hand wheel 14. Pressure gage 15. Annular space outlet valve 16. Cellar

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.

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 - Drilling During 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 4

Wellheads - Completed well After the tubing is installed :

The BOP's are removed

Xmas Tree

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

Wellhead

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Wellhead systems must be designed to : 1

Withstand tensile loads of suspended tubulars

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Provide a pressure sealing capability ISOLATE the well from the external

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

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environment ISOLATE between casings and downhole formations MAINTAIN PRESSURE during well control operations, well testing or shut in periods.

What does a wellhead do ? 1

HANG-OFF WEIGHT

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CONTAINS PRESSURE

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MONITOR THE WELL SAFETY PROVIDE A BASE FOR THE XMAS TREE

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Surface Wellheads

Conventional spooled system BOP Stack

Tubing Head Spool Casing Head Spool

Casing Head Housing

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What are the main components ? Xmas Tree

Tubing Head Spool

Casing Head Spool

Casing Head Housing 10

Surface Wellhead schematic • Medium cost spool system

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Casing Head Housing First 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 DescriptionTop connection flanged (standard) Ring groove

Landing area for Casing Hanger

Side outlets threaded or studded

Test port Slip-on weld or threaded bottom connection 14

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 Plate The casing head may be used in conjunction with a base plate for more effective weight distribution.

Cellar

Conductor pipe 18

Surface casing

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 Spools Second element of the wellhead

Normally not threaded as pressures higher Eg >3000psi.

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Next Section is Installed Casing 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 Top connection flanged (standard)

Landing area for Casing Hanger

Bottom connection compatible with the top connection on the previous casing head or spool 30

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

Test port

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

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

Landing area

Intermediate or Production Casing

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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 Spools Third 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 FOR TUBING HANGER VALVE REMOVAL PLUG THREADS

TEST PORT Pack off designed to fit around OD of production casing 41

Tubing Hangers Tubing Hanger Tubing Head Spool

Tubing Bonnet

Tubing Hanger

Production casing Tubing

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Tubing Head Spool

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 Xmas 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

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