positive and adjustable chokes manual

Field Service Manual

Prepared By: Reviewed By: Approved By: SM-009

Eric Calzoncinth Rev WIP

Marion Robertson Bruce Ross Eric Calzoncinth of 26

5-3-GL-GL-WES-00XXX August 2014 August 2014 August 2014

©2014 Weatherford International Ltd. All Rights Reserved

Wellhead Field Service Manual Adjustable and Positive H2 Chokes

Publication: SM-009

Release Date: August 2014





5-3-GL-GL-WES-00XXX March 2014 March 2014 August 2014

Table of Contents

Weatherford Production Chokes ............................................................................................................................ 1

Equipment Description ............................................................................................................................... 2

Function ....................................................................................................................................................... 2

Connection Configurations ........................................................................................................................ 2

Models .......................................................................................................................................................... 2

Sizes, Weights and Specifications ............................................................................................................ 3

Operating the Choke ................................................................................................................................................ 4

Adjustable Choke ........................................................................................................................................ 4

Positive Choke ............................................................................................................................................ 4

Troubleshooting ....................................................................................................................................................... 5

Recommended Lubrication Types ......................................................................................................................... 5

Choke Installation .................................................................................................................................................... 6

Adjustable and Positive Choke ................................................................................................................. 6

Testing the Connection .............................................................................................................................. 6

Records Keeping ......................................................................................................................................... 6

WFT-H2 Adjustable Choke ...................................................................................................................................... 7

Description .................................................................................................................................................. 7

Applications ................................................................................................................................................. 7

Specifications .............................................................................................................................................. 7

Field Inspection and Preventive Maintenance ......................................................................................... 8

Disassembly, Assembly and Pressure Testing in the Shop ................................................................ 11

WFT-H2 Positive Choke ......................................................................................................................................... 18

Description ................................................................................................................................................ 18

Choke Bean Size and Compatibility ........................................................................................................ 18

Applications ............................................................................................................................................... 18

Specifications ............................................................................................................................................ 18

Field Inspection and Preventive Maintenance .............................................................................. 19

Disassembly, Assembly and Pressure Testing in the Shop .......................................................... 25





5-3-GL-GL-WES-00XXX October 2013 October 2013 August 2014

Weatherford Production Chokes

Equipment Description

Production chokes are used in production systems to regulate the flow of oil and gas. They are installed in the production tree and are considered part of the tree’s components. A production choke may also be included in downstream production lines and/or facilities to regulate flow downstream of the production tree. They are also commonly incorporated in many rotary drilling rigs’ choke and kill manifold systems to regulate flow as needed.

The body of a choke valve is typically L‐shaped, with an upstream inlet and a downstream outlet. Flow is restricted by a replaceable element which has an orifice through the center of the element. The positive choke incorporates a positive type choke bean with a predetermined ID to regulate flow at a predetermined rate. The adjustable choke is a needle and seat design.

The pressure rating of the inlet flange, body and bonnet assembly determine the maximum rating of the choke. Chokes which have an inlet flange with a higher pressure rating than that of the outlet flange have a double pressure rating.

When hydro testing a choke with different inlet and outlet pressure ratings, the choke should be pressured to the lower pressure rating.

Chokes are not intended to be used as shutoff devices and may not provide a fluid-tight shut-off. Always use a gate valve to completely shut-off well fluids.

Function

Assists in the controlled flow of fluids.

Maintains back pressure in the well.

Relieves well pressure safely after a kick.

Increases the ultimate recovery of hydrocarbons from a formation.

Controls the rate of formation pressure decline.

Diminishes sand production and eliminates formation damage from water coning and gas fingering.

Reduces tree and flowline damage from erosion caused by velocity and cavitation.

Connection Configurations

Flange, union and threaded

Models

H2 Adjustable Manual Choke

H2 Positive Manual Choke






Weatherford Production Chokes (Continued)

Sizes, Weights and Specifications

Specification PSI Size (Inches/Millimeters)

A B Ring

1" Maximum Orifice2 1/16 - 2000 Flange 2000 6.50"/165mm 5.90"/150mm R232 9/16 - 2000 Flanqe 2000 6.69"/170mm 6.30"/160mm R262 1/16 - 5000 Flange 5000 7.99"/203mm 6.89"/175mm R242 9/16 - 5000 Flange 5000 8.27"/210mm 6.93"/176mm R272 1/16 - 10000 Flanqe 10000 8.82'' 224mm 7.68"/195mm BX152 2 9/16 - 10000 Flanqe 10000 9.33"/237mm 8.19"/208mm BX1532 1I16 - 15000 Flange 15000 10.31 "/262mm 8.59"/225mm BX1522 9/16 - 15000 Flanqe 15000 11.73"/298mm 10.51 "/267mm BX153

2'' Maximum Orifice3 1 /8 - 2000 Flange 2000 9.06"/230mm 7.28"/185mm R312 9/16 - 5000 Flange 5000 10.43"/265mm 7.68"/195mm R272 9/16 - 10000 Flanqe 10000 11.73"/298mm 10.40"/264mm BX1532 9/16 - 15000 Flange 15000 11.73"/298mm 10.40" /264mm BX153 3 1 /8 - 3000 Flange 3000 11.73"/298mm 8.59"/225mm R313 1 /8 - 5000 Flange 5000 11.73"/298mm 8.59"/225mm R35

3 1 /16 - 10000 Flange 10000 11.73"/298mm 10.40" /264mm BX154 3 1 /16 – 15000 Flange 15000 11.73"/298mm 10.40" /264mm BX1544 1/16 - 3000 Flange 3000 11.73"/298mm 10.40"/264mm R374 1 /16 - 5000 Flange 5000 11 73"/298mm 10 40" /264mm R394 1 /16 - 10000 Flange 10000 13 78"/350mm 11.37/289mm RX155

3'' Maximum Orifice4 1/16 - 3000 Flange 3000 11.73"/298mm 1 0.40" /264mm R37 4 1 /16 - 5000 Flange 5000 11.73"/298mm 1 0.40" /264mm R39






Operating the Choke

Adjustable Choke

Operation is fairly straightforward, but an important part of well control.

1. Open the choke by turning the handwheel in a counter-clockwise rotation. This pulls the stem up and allows well fluids to flow around the tip of the stem, through and out the choke.

2. Close the choke by turning the handwheel in a clockwise rotation. This rotates the stem into the bore of the choke until it meets the choke seat. In the fully closed position, well flow is reduced but not pressure sealed.

Never force the stem down into the choke seat. Doing so will damage both components and shorten equipment life.

3. If a fixed flow rate is required, the choke can be locked into position.

4. The choke indicator is calibrated and indicates the rate of flow that the choke is operating.

5. While the equipment is in operation and under pressure, monitor the fluid flow carefully.

Positive Choke

Operation is essentially automatic but an important part of well control.

1. While the equipment is in operation and under pressure, monitor the fluid flow carefully. The choke bean can be changed out for a different size to achieve the desired flow rate.






Troubleshooting

This chart identifies problems that may be found in the field or shop and offers possible causes and solutions. If there are any problems that occur outside the scope of this chart, contact the appropriate Weatherford authority.

Trouble Probable Cause Remedy

Obstructed flow Restriction in choke body Disassemble and flush body cavity as required.

Erratic operation

Accumulation of foreign matter in the body

Flush out body and replace bean (in a positive choke) as needed.

Damaged Bean (in Positive Choke) Replace as needed.

Leaking Connections Inspect for leaks, repair or replace bean gasket, ring gasket, studs or nuts as needed.

Leaking Bonnet Inspect O-Ring and replace as needed.

Bonnet Nut not tight Tighten or replace bonnet nut.

Damaged Bonnet connection Replace bonnet assembly as needed.

Flange connection damaged Repair or replace choke body.

Leaking bonnet Loose Connection Reconnect bonnet nut. O-Ring Leak Replace O-Ring.

Leaking bonnet - pressure escaping at bonnet cap to bonnet connection

Bonnet Nut not tight Tighten or replace bonnet nut.

Bonnet O-Ring Damaged Replace O-Ring.

Flange connection not sealing

Flange Surface Damage Repair or replace choke body. Gasket Damage Replace gasket ring.

Stud/Nut Torque Re-torque flange per API specifications.

Ice forming on OD of choke

Wrong Size of Choke Notify client of problem and contact Weatherford Engineering for proper sizing instructions.

Hydrates in Medium Notify client of problem .

High BTU Gas Notify client of problem and contact Weatherford Engineering.

Recommended Lubrication Types

While other lubricants may be acceptable, Weatherford chokes have a proven record of reliable service when using the following lubricants.

Ring grooves and studded connection tapped holes: Lubriplate 130-AA.*

Lockscrew threads, and fitting ports: Anti-Seize ET-180.*

*WT-512 Lubrication Requirements for Assembly






Choke Installation

Installation of Adjustable and Positive Chokes

1. Close all valves necessary to isolate the surrounding equipment and the choke being installed from well pressures. Tag the surrounding equipment as Out of Service.

Pressure entering the choke during installation or removal can result in serious injury and catastrophic failure of the equipment.

2. Verify the weight and dimensions of the choke assembly and prepare for a safe lift, using appropriate slings or other approved lifting devices.

3. Inspect the choke and surrounding line equipment. Verify that:

Assembly is in order, with all components present and installed correctly.

Choke is in the fully open position. Ring gaskets and stud kits are new

and the appropriate size. Connecting equipment flanges are

in good condition and free of grease or debris.

If installing a positive choke, bean size is correct.

4. Wipe the mating ring grooves of the choke assembly with a light oil or grease.

Excessive oil or grease can prevent a positive seal from forming.

5. Install the mating ring gaskets.

6. Install the choke in the line, situated so that gas or fluid flows into the inlet

connection. The flow will make a 90 degree turn to pass through the orifice opening in the seat, and then exit through the outlet flange. Most chokes have a flow arrow indicator (

) on the OD of the body to assist in the direction of flow. The outlet flange is the flange located opposite the bonnet on an adjustable choke, or the blanking cap on a positive choke.

The choke should always be installed in the direction indicated by the flow arrow indicator and the configuration of the inlet and outlet flow ports.

The installed orientation of the choke is normally at the point between upright and horizontal. A different installation orientation will not affect performance; however, it is not recommended because of possible difficulties in disassembly and reassembly during routine maintenance, and the potential for solids accumulating along the underside of the internally threaded components.

7. Make up the inlet and outlet connections hand-tight and then torque to the torque required per API.

Testing the Connection

1. Open the upstream valves slowly and carefully, allowing pressure to enter the choke and watching for any leaks both in the choke and downstream. If there are leaks, close the valves and consult the Troubleshooting Guide.

2. Repeat this procedure until no leaks are observed.

3. Test the flow rate of the installation, verifying that the downstream pressure is the specified flow rate.

Recordskeeping

1. Record the equipment information, noting:

Model Number Serial Number Date of Installation Type of Flow Medium, if possible Any other pertinent information






WFT-H2 Adjustable Choke

Equipment Description

The Weatherford Model H2 Adjustable Choke provides flexible control of flow rates by rotating a tapered needle stem into a tapered choke bean orifice to mechanically choke the flow. This allows the operator to obtain the desired flow rate or downstream pressure. Clockwise rotation of the handwheel reduces the orifice opening. Counter-clockwise rotation of the handwheel increases the orifice opening. It can be locked into position if a fixed flow rate is required by tightening the thumb screw on the stem. The orifice size is read from an indicator (if equipped) marked in 1/64th increments. The indicator is lined up with a V-notch machined into the top of the bonnet, which allows for calibration.

The adjustable choke can be converted in the field to a positive, or fixed orifice choke, as required.

Applications

Production Operations

Drilling Operations

Effective in bringing wells on gradually

Effective in optimizing natural gas lift flow

Specifications

Nominal Sizes:2", 3", 4"

Needle/Maximum Orifice Size:1", 2", 3"

Working Pressure: 2000 through 15,000 psi

Operating Temperatures: API ratings K, L, P, R, S, T, U, X -50 deg F to +250 deg F (-45 deg C to +121 deg C). (X and Y temps derated per API6A.)






WFT-H2 Adjustable Choke (Continued)

Field Inspection and Preventative Maintenance

Every 6 months, or after every ten cycles (counting every flow re-set or adjustment of significant pressure change as a cycle), whichever comes first, the choke body and bonnet should be inspected, disassembled, cleaned and lubricated and re-assembled.

If the well takes a kick, or after well clean-up activities, maintenance and lubrication should be expedited and completed as soon as possible, due to the usually unknown nature of the fluids produced during these events.

The choke assembly does not have to be removed from service during most servicing and maintenance; however, disassembly can only be done while equipment is out of service and isolated from pressure.

1. While the choke is in production and under pressure, visually inspect the production line, choke and downstream flow for leaks or flow restrictions. If found, identify the source.

2. After the visual inspection, close off production flow to the area, tag the choke and surrounding equipment as Out of Service and ensure that the choke is isolated from all pressure, upstream and downstream.

Any pressure entering a valve or choke during maintenance or repair can result

in serious injury and catastrophic failure of the equipment.

3. Open the choke fully, rotating the handwheel clockwise.

4. Loosen the vent fitting carefully to vent the body cavity of any residual pressure.

5. Loosen the wing nut, using a hammer and striking the nut in a counter-clockwise direction.

Always wear protective eyewear when striking any object with a hammer or other metal tools.

There must be a minimum of ten inches clearance with the stem in the fully open position to remove the bonnet.

6. With the wing nut loose, pull the handwheel, stem, wing nut and bonnet assembly out of the body.

WFT chokes have a built-in safety feature that allows residual pressure to escape before the wing nut and blanking cap is completely removed, by venting the inside of the choke body to the atmosphere after one turn of the wing nut. However, caution should be taken to stand to one side of the assembly when removing the wing nut and blanking cap, as pressure may still be trapped in the choke.







7. Inspect these critical areas of the choke body and verify that:

Bonnet to body seal surface and choke bore is clean and free of nicks, scratches or wear from flow.

Orifice is free of debris with no buildup of paraffin or other trash.

Choke seat and needle do not exhibit excessive wear.

8. Clean the choke body OD threads, seal areas and bonnet bore and apply a light coat of grease.

9. Inspect the seat and seat gasket ring. Replace the ring if worn or damaged.

If internal wear or build-up cannot be fixed, remove the choke from production and send for replacement.

10. Inspect the bonnet assembly and verify that all components are complete and in good order.

11. Remove the wing nut and visually inspect the OD and lugs for wear.

12. If any of the lugs have been beaten down into the OD of the nut, replace the wing nut.

13. Clean and grease the nut threads.

14. Inspect the bonnet body and ring grooves and ensure that surfaces are free from burrs or nicks.

15. Apply a light coat of grease to the bonnet body and grooves.

16. Inspect the bonnet O-Rings and packing. Replace if worn or damaged.

17. Inspect the choke seat and needle. Replace if excessive wear is seen.

Choke Bodies may often be fitted with a solid ½” pipe plug in place of the vent fitting.







After a thorough inspection and replacement of damaged parts and greasing as instructed, the choke is ready for reassembly.

18. Ensure that the stem is in the fully open position.

Damage to the stem and seat may occur when hammering the wing nut to the body stem if the stem is not in the fully open (retracted) position.

19. Carefully align the bonnet onto the choke body, rotating the wing nut clockwise until hand tight.

20. Check for unhampered operation of the stem by rotating the handwheel, ending with it still in the fully open position.

21. Using a hammer, tighten the wing nut completely, rotating it clockwise until the bonnet is securely in place.


22. Tighten the vent fitting.

23. With the choke now ready to return to service, slowly bring it online by opening upstream valves, watching for any leaks or problems as pressure returns to the equipment. If leaks or problems occur, immediately shut the valves and consult this section’s Troubleshooting Guide. Repeat this process until no more leaks are observed.

24. Record the procedure as required, noting:

Model Number Serial Number Date of Procedure







Disassembly, Assembly and Testing in the Shop

This procedure is best done in the optimum location of a shop environment. If it is to be done in the field, sufficient area must be planned for and the correct tools and testing equipment be made available.

Disassembly

1. Close the necessary upstream and downstream valves to isolate the choke.

2. Loosen the body vent fitting to vent any residual pressure in the choke body.

Take caution and be careful of hand and body placement in any situation where pressure may be present.

3. Loosen the wing nut by striking the lugs with a hammer and rotating in a counter-clockwise manner.


4. With the wing nut now free from the choke body, pull the handwheel, stem, wingnut and bonnet assembly out of the choke body.

5. Remove nut, washer and handwheel.

6. Loosen the indicator set screw and remove the indicator.

7. Remove the thumb screw, wing nut and stem from the bonnet.

8. Remove the wing nut.

9. Holding the bonnet securely, use the handwheel to rotate the stem clockwise, passing it through the packing set and junk rings and out the bonnet.

Do not use a pipe wrench or other tool type on the stem/packing seal during this process.







10. Remove the ball (if equipped) from the thumb screw hole.

11. Remove the retainer ring with appropriate snap ring pliers.

Always wear protective eyewear when manipulating the snap ring.

The junk rings have a tight tolerance in the bonnet. Use caution to avoid cocking the junk ring in the bore and scarring the finish.

12. Remove the lower junk ring.

13. Remove the packing set carefully to avoid scarring the finished surface of the packing box and discard.

14. Remove the upper junk ring in the same manner as the lower junk ring.

15. Remove the bonnet O-Ring and discard.

16. Using a H2 seat wrench, remove the seat/bean from the choke by sliding the wrench over the seat/bean hex and rotating counter-clockwise. Remove the seat/bean from the choke body.

17. With the choke now fully disassembled, thoroughly clean all components and remove any old lubricants, built-up paraffin or other residuals.

18. Lightly sand out or file any burrs and chips, especially threaded areas.

19. Inspect all sealing surfaces for visual signs of corrosion or erosive affects:

Body end connections. Bonnet-to-body or wingnut-to-body

sealing surfaces.

Packing box finish; surface should be clean and smooth. Shoulder and threads of the wing nut. Internal body seat threads and gasket seal area. Choke stem; threads, packing seal area, stem tip. Internal bonnet/stem threads. All internal body surfaces.







Assembly

1. Assemble the choke components and verify that:

All parts are clean and correct size. Rings gaskets and packings are

new and the correct size.

Packing sets and bonnet O-Rings are replaced as standard.

2. Install a new seat gasket on the seat.

3. Grease both the threads of the seat and the inside seat lip of the choke body with a quality anti-seize lubricant.

4. Place the seat into the choke body. Use care to avoid dropping the seat in the body and damaging the threads. With a H2 seat wrench holding the seat hex, turn the wrench clockwise to tighten the seat into the choke body

Proper torque is 600 ft-lbs.

5. Remove the seat wrench and store for future use.

6. Place the bonnet body on a flat surface with the packing box up, and grease the packing bore.

7. Grease the upper junk ring and carefully insert it into the packing box bore of the bonnet. The junk rings have a close tolerance and can get cocked and logged in the bore of the packing box. Take care to install slowly and evenly to avoid scarring the wall of the packing box.

8. Grease the inside and outside diameter of the new packing set and carefully slide it into the bonnet packing box.

If the choke uses Chevron style packings with V-rings, the direction of the packing is important for proper operation. The V shape must be oriented so that the wide end of the V shape faces the internal pressure of the choke body.







9. Grease the lower junk ring and carefully insert into the packing box.

10. Grease the packing retainer ring and install it in the groove ring using appropriate snap ring pliers.

Always wear protective eyewear when manipulating the snap ring pliers.

11. Lay the bonnet on its side.

12. Lubricate the stem threads with a quality anti-seize lubricant.

13. Carefully slide the stem, threaded end first, through the packing end of the bonnet body and up, until the stem threads are visible at the top of the bonnet where the indicator is normally located.

14. Engage the threads of the stem with the threads of the bonnet body.

The handwheel can be temporarily installed onto the stem to facilitate turning the stem into the bonnet. Once installed, remove the handwheel.

15. Grease the OD bonnet ring grooves and grease and install the two bonnet O-rings.

16. Grease the threads inside the wing nut and slide it over the bonnet until it comes to rest on the shoulder of the bonnet.

17. Grease and install two balls (if equipped) or one copper plug (if so equipped for high temperature service), into the thumbscrew hole.

18. Lubricate the threads on the thumbscrew with a quality anti-seize lubricant and install on the bonnet.

19. Install the indicator on the stem. Do not tighten the set screw at this time.

20. Grease the inside of the handwheel and slide onto the stem.

21. Install the flat washer on top of the handwheel.

22. Lubricate the stem threads with quality anti-seize lubricant and install the hex nut.

23. Rotate the handwheel counter-clockwise until the stem is in the fully open position.

The stem must be fully in the open position to protect the stem threads as well as the stem tip and choke seat during the following step.







24. Carefully align the bonnet onto the choke body and rotate the wing nut clockwise until it is hand tight. Check for unhampered operation of the stem by rotating the handwheel. With the stem in the fully open position, rotate the wing nut clockwise by striking the lugs of the wing nut with a medium size sledge hammer to secure the bonnet in place.

Always wear protective eyewear when striking any object with a hammer or other metal tools

25. Wrap the vent fitting threads with teflon tape, grease the threads of the body vent fitting and the body with a quality anti-seize lubricant, and install the vent fitting by rotating the vent fitting threads clockwise into the choke body.







26. Carefully align the bonnet onto the choke body and rotate the wing nut clockwise until it is hand tight. Check for unhampered operation of the stem by rotating the handwheel. With the stem in the fully open position, rotate the wing nut clockwise by striking the lugs of the wing nut with a medium size sledge hammer to secure the bonnet in place.

Always wear protective eyewear when striking any object with a hammer or other metal tools

27. Wrap the vent fitting threads with teflon tape, grease the threads of the body vent fitting and the body with a quality anti-seize lubricant, and install the vent fitting by rotating the vent fitting threads clockwise into the choke body.

Indicator Calibration

1. Set the indicator by rotating the handwheel in a clockwise manner and lower the stem until it touches the seat.

Do not force the stem into the seat as this will cause damage to the stem and seat.

2. Line up the -0- mark on the indicator (if equipped) with the notch marked on top of the bonnet, and tighten the set screw.

Do not over tighten the set screw. The indicators are normally made of PVC

and the threads will strip if excessively tightened.

3. Operate the stem to its full open position until the indicator shows the maximum opening size lined up with the notch. The stem should rotate smoothly through its full stroke.

If there is evidence of rough operation, the threads on the stem and or the bonnet should be inspected, serviced or replaced.

The choke assembly is now completely assembled and ready to be pressure tested.

Chokes are not intended to be used as shutoff devices and may not provide a fluid-tight shut-off. Always use a gate valve to completely shut off well fluids.







Pressure Testing

1. After assembly is complete, test the equipment by attaching a pressure test device to the inlet port and another to the outlet port. Pressure test to:

The rated working pressure for 2 to 5K equipment maximum per API6A.

The rated working pressure for 10 to 15K chokes maximum per API6A.

If the choke assembly is configured with flanged connections consisting of two different working pressure ratings, the assembly should only be tested at the lower pressure connection of the two.

2. Watch for leakage at:

Bonnet O-Rings Packing Seals Vent Fitting/Pipe Plug Inlet and Outlet Connections

3. If there is leakage, remove the pressure

devices and refer to the Troubleshooting Guide for the correct solution.

4. Re-attach the pressure devices and test until no leakage is seen.






WFT-H2 Positive Choke

Description

The simplest type of choke, a positive choke is a non-adjustable fixed orifice version of the adjustable choke. It is made up of a body with an inlet and an outlet oriented 90 degrees apart. A choke flow bean provides a predetermined flow rate by restricting the outlet flow. The cavity in the choke body helps to slow down the fluid before it is forced through the restriction.

Choke Bean Size and Compatibility

To determine the correct size of choke bean to be used, the system engineer calculates the necessary flow rate based on anticipated well fluids. The correct sized flow bean is then manually installed into the choke to provide the predetermined flow rate through the bean orifice. Flow bean orifices are usually measured in 64th’s of an inch.

An adjustable choke assembly can be converted to a positive choke assembly by replacing the adjustable choke seat with a positive choke bean and the adjustable bonnet assembly with a blanking cap. The wing nut from the adjustable bonnet assembly may be used.

Chokes are not intended to be used as shutoff devices and may not provide a fluid-tight shut-off. Always use a gate valve to completely shut-off well fluids.

Applications

Production, drilling, or well service operations where there is no need for adjustment of flow.

The positive choke is not used in drilling or well control operations unless there is a specific requirement. By its nature the equipment can be severely damaged if used in situations outside its purpose.

Positive chokes should not be included in the drilling choke manifold unless there is a specific production-well testing requirement. If a positive choke is used in a manifold system, it is recommended that the system be spaced so that an additional drilling or adjustable choke can readily fit.

Specifications

Nominal Sizes:2", 3", 4"

Needle/Maximum Orifice Size:1", 2", 3"

Working Pressure: 2000 through 15,000 psi

Operating Temperatures: API ratings K, L, P, R, S, T, U, X -50 deg F to +250 deg F (-45 deg C to +121 deg C). (X and Y temps derated per API6A.)






WFT-H2 Positive Choke (Continued)

Field Inspection and Preventative Maintenance

Every 6 months, or after every ten cycles (counting every flow re-set or adjustment of significant pressure change as a cycle), whichever comes first, the choke body and bonnet should inspected, disassembled, cleaned and lubricated and re-assembled.

If the well takes a kick, or after well clean-up activities, maintenance and lubrication should be expedited and completed as soon as possible, due to the usually unknown nature of the fluids produced during these events.

1. While the choke is in production and under pressure, visually inspect the production line, choke and downstream flow for leaks or flow restrictions. If found, identify the source.

The positive choke assembly does not have to be removed from service during most servicing and maintenance; however, valves must be closed and the equipment isolated from pressure.

2. After the initial inspection, close off production flow to the area, tag the choke and surrounding equipment as Out of Service and ensure that the choke is isolated from all pressure, both upstream and downstream.

Before work commences, ensure that equipment is isolated from all pressure and clearly tagged as out of service. Any pressure entering a valve or choke

during maintenance or repair can result in serious injury and catastrophic failure of the equipment.

3. Bleed all pressure off the isolated flowline.

4. Loosen the bleed plug carefully to vent any remaining pressure in the choke body cavity.

5. Loosen the wing nut, striking it with a hammer in a counter-clockwise manner.


Weatherford’s built-in safety feature allows residual pressure to escape before the wing nut and blanking cap is completely removed, by venting the inside of the choke body to the atmosphere after one turn of the wing nut. However, caution should be taken to stand to one side of the assembly when removing the wing nut and blanking cap, as pressure may still be trapped in the choke.

6. Continue rotating the wing nut and remove the blanking cap and wing nut from the choke body.







7. Remove the choke bean assembly from the bore of the choke. Inspect and verify that the choke bean threads are clean and undamaged, with no visible wear or deposit build-up.

This area is susceptible to wear and erosion when operated with fluids containing high sand or viscous content. Closely inspect for thread wear, erosion and/or corrosion of all internal components

The choke bean assembly may include a choke bean insert (as shown).

8. Remove and discard the used choke bean gasket ring, and install a new appropriately sized gasket.

9. Inspect the following critical areas of the choke body and verify that:

Bonnet to body seal surface clean and free of any nick or scratches.

Body bore is clean, undamaged and free of debris.

10. Clean the choke body OD threads, seat thread areas and bore and apply a light coat of a quality anti-seize.

If internal wear or build-up cannot be fixed, remove the choke from production and send for repair.

11. Remove the retainer ring from the blanking cap and separate the wing nut from the blanking cap.

12. Remove the blanking cap O-ring, discard it, and install a new appropriately sized O-ring.

13. Inspect the blanking cap assembly and verify that all components are complete and in good order.

14. Inspect the wing nut OD and lugs. If any of the lugs have been beaten down into the OD of the nut, or the threads are damaged, replace the nut.

15. Clean and lubricate the nut threads a quality anti-seize.







After a thorough inspection and replacement of damaged parts and greasing as instructed, the choke is ready for reassembly.

16. Holding the choke bean, grease the threads on the bean and in the choke body with a quality anti-seize lubricant. Place the bean in the choke body.

Use care to avoid dropping the bean in the body and damaging the threads.

17. Using an H2 wellhead bean wrench to hold the bean hex, turn the wrench clockwise, tightening the bean into the choke body.

Proper torque is 600 ftlbs.

18. Remove the bean wrench and store for future use.

19. Grease and install a new appropriately sized O-ring in the blanking cap groove.

20. Grease the mating surfaces of the blanking cap and choke body and place the blanking cap on the choke body.

21. Apply a good quality anti-seize lubricant on the threads of the choke body and install the wing nut onto the choke body, using a hammer and rotating in a clock-wise direction until the wing nut and blanking cap are secure on the choke body.


22. Install the retainer snap ring with a pair of appropriate snap ring pliers in the groove on the blanking cap.


23. Wrap the pipe plug threads with Teflon tape, grease the threads of the pipe plug and the blanking cap with a quality anti-seize lubricant, and install the pipe plug by rotating the pipe plug threads clockwise into the blanking cap.

24. With the choke now ready to return to service, slowly bring it online by opening upstream valves, watching for any leaks or problems as pressure returns to the equipment. If any leaks or problems are observed, immediately shut the valves and consult this section’s Troubleshooting Guide.

25. Repeat the step until no leaks are observed.

26. Record the procedure as required, noting:

Model Number Serial Number Date of Procedure







Disassembly, Assembly and Pressure Testing in the Shop

This procedure is best done in the optimum location of a shop environment. If it is to be done in the field, sufficient area must be planned for and the correct tools and testing equipment be made available.

Required replacement parts are choke bean gasket rings and all O-rings. All other parts are replaced depending on evidence of wear, damage or corrosion.

Disassembly

1. Loosen the bleed plug carefully to vent any residual pressure in the choke body cavity, if so supplied.

Take caution and be careful of hand and body placement in any situation where pressure may be present.

2. Loosen the wing nut, striking it with a hammer in a counter-clockwise manner.


Weatherford’s built-in safety feature allows residual pressure to escape before the wing nut and blanking cap is completely removed, by venting the inside of the choke body to the atmosphere after one turn of the wing nut. However, caution should be taken to stand to one side of the assembly when removing the wing nut and blanking cap, as pressure may still be trapped in the choke.

3. Continue rotating the wing nut and remove the blanking cap and wing nut from the choke body as one assembly.







4. Remove the choke bean assembly from the bore of the choke. Inspect and verify that the choke bean, bean components and threads are clean and undamaged, with no visible wear or deposit build-up.

This area is susceptible to wear and erosion when operated with fluids containing high sand or viscous content. Closely inspect for thread wear, erosion and/or corrosion.

The choke bean assembly may include a choke bean insert (as shown). This insert is permanent and is not replaceable.

5. Remove and discard the used choke bean gasket ring and choke ring, as required.

6. Inspect the following critical areas of the choke body and verify that:

Bonnet to body seal surface clean and free of any nick or scratches.

Body bore is clean, undamaged and free of debris.

7. Clean the choke body OD threads, seat thread areas and bore and apply a light coat of grease.

If internal wear or build-up cannot be fixed, remove the choke from production and send for repair.

8. Remove the retainer ring from the blanking cap and separate the wing nut from the blanking cap.

9. Remove the blanking cap O-ring, discard it, and install a new appropriately sized O-ring.

10. Inspect the blanking cap assembly and verify that all components are complete and in good order.

11. Inspect the wing nut OD and lugs. If any of the lugs have been beaten down into the OD of the nut, replace the nut.

12. Clean and grease the nut threads.







Assembly

1. Assemble the choke components and verify that:

All parts are clean and correct size. Ring gaskets and packings are new

and the correct size. 2. Install a new appropriately sized gasket

onto the choke bean.

3. Holding the choke bean, grease the threads on the bean and in the choke body with a quality anti-seize lubricant. Place the bean in the choke body.

Use care to avoid dropping the bean in the body and damaging the threads.

4. Using an H2 wellhead bean wrench to hold the bean hex, turn the wrench clockwise, tightening the bean into the choke body.

Proper torque is 600 ftlbs.

5. Remove the bean wrench and store for future use.

6. Grease and install a new appropriately sized O-ring in the blanking cap groove.

7. Lubricate the mating surfaces of the blanking cap and choke body and place the blanking cap on the choke body.

8. Apply a good quality anti-seize lubricant on the threads of the choke body and install the wing nut onto the choke body, using a hammer and rotating wing nut in a clock-wise direction until the wing nut and blanking cap are secure on the choke body.


9. Install the retainer snap ring with a pair of appropriately sized snap ring pliers in the groove on the blanking cap.


10. Wrap the pipe plug threads with Teflon tape, grease the threads of the pipe plug and the blanking cap with a quality anti-seize lubricant, and install the bleed plug by rotating the pipe plug threads clockwise into the blanking cap and tighten fully.







Pressure Testing

1. After assembly is complete, test the equipment by attaching a pressure test device to the inlet port and another to the outlet port. Pressure test to:

The rated working pressure for 2 to 5K equipment maximum per API6A.

The rated working pressure for 10 to 15K chokes maximum per API6A.

If the choke assembly is configured with flanged connections consisting of two different working pressure ratings, the assembly should only be tested at the lower pressure connection of the two.

2. Watch for leakage at:

Bleed Plug/Pipe Plug Around Wing Nut Inlet and Outlet Connections

3. If there is leakage, remove the pressure

devices and refer to the Troubleshooting Guide for the correct solution.

4. Reattach the pressure devices and test until no leakage is present.

positive and adjustable chokes manual

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