Installation procedure for Prepacked Screens in Horizontal Open Hole Section


These example procedures are based on a balanced rotationally locked washdown system.

-   The following procedures assume the open hole horizontal section to have been drilled with sized  calsium carbonate in polymer / brine based fluid.

-   It should be considered to condition the open hole section by a wiper trip prior to pulling out and displace the hole to fresh mud giving a minimum safe overbalance.

Running Procedure

1. Displace the hole from 0m - 350m riser to clear filtered 1.15 SG NaCl brine when POOH to avoid  plugging screens while RIH. No special requirements to cleanliness needs to be addressed.

2. Pick up the following (listed bottom up). Hang off screens using Double Collar Catch Elevators :

a.      Circulating Bullnose Assembly Consisting of :

  • Seal Bore Receptacle, Size 3.875" w/ 6-5/8" BTC Box x Pin w/ Int. 4-1/2" New Vam Box Down. (13% Chrome Material).
  • Pup Joint, 20ft w/ 4-1/2" New Vam Pin x Box. (13% Chrome Material).
  • Model 'HL' Sliding Sleeve, Size 4-1/2" w/ 4-1/2" New Vam Pin x Box
  • Pup Joint, 20ft w/ 4-1/2" New Vam Pin x Pin. (13% Chrome Material).
  • Bull Plug, Size 4-1/2" w/ 4-1/2" New Vam Box Up. (13% Chrome Material).
  • 2 ea External By-Pass Blank, 20ft w/ 6-5/8" BTC Box x Pin. (316L Material).
  • Double V-Set Shoe, Size 6-5/8" w/ 6-5/8" BTC Box Up. (Std Material).

b.     X joints Baker SlimPak Screen, Size 6-5/8" x 0.020" gauge w/ 12/20 US Mesh Bakerbond w/ 6-5/8" BTC Box x Pin. 316L Schedule 80 Base Pipe w/ 316L Jacket and Inner Mesh. 20 ft Base Pipe w/ 21" Upper Blank, 15" Lower Blank (incl. threads) and 17ft Jacket Length.  Normal Hole Pattern (108 holes per foot).

c.      X joints Blank Pipe, 20ft, Size 6-5/8" w/ 6-5/8" BTC Box x  Pin. (316L Sch 80 Material.)

3. Rig Up Stripping Table w/ Bowl and Slips for 3-1/2" Wash Pipe.

4. Pick Up and run the washpipe as follows :

a.      Model 'HB-1' Shifting Tool, Size 4-1/2"

b.     1 ft Spacer

c.      Model 'HB-1' Shifting Tool, Size 4-1/2"

d.     Crossover to 2-3/8" Hydril CS Box Up

e.      Pup Joint, 10ft w/ 2-3/8" Hydril CS Box x Pin

f.      Ported Pup Joint, 10ft w/ 2-3/8" Hydril CS Box x Pin

g.     Locator Seal Assy, Size 120-38 w/ 3-1/2" PH-6 Box x 2-3/8" Hydril CS Pin

h.      X Joints Washpipe, 30ft w/ 3-1/2" Hydril PH-6 Box x Pin

i.       Crossover Sub w/  3-1/2" EU 8rd Box x 3-1/2" PH-6 Pin

j.       Model 'E' Hydro-Trip Pressure Sub f/ 1-1/2" Ball w/ 3-1/2" EU 8rd Box x Pin

k.      Last 50 ft, run 10ft Pup Joints

5. Locate Stinger into Bullnose Assembly. Space out w/ pup joints for Packer Assembly.

Note: Do not pick up more than 3 meters after locating. This might permanently close the sliding sleeve.

6. Pick up the following ( listed bottom up ), which will have been preassembled. Use 3-1/2" Drill Pipe Elevator.

a.      Baker Model 'C' Knock Out Isolation Valve with 6 5/8" BTC box x pin.

b.     Crossover Sub with 7" BTC box x 6-5/8" BTC pin. (13% Chrome Material.)

c.      7" Seal Bore Extension, 4.00 meter long w/ 7" BTC pin x pin.

d.     Seal Bore Receptacle, Size 6.000" with 7"  BTC box x box.

e.      Baker Model 'S' Gravel Pack extension with sliding sleeve, Size 190-60 w/ 10' upper extension and 3.50 meter lower extension with 7 5/8" BTC pin up x 7" BTC pin down.

f.      Baker Model "SC-1R" Gravel Pack Packer - Size 96A2-60 w/ 7 5/8" S.C. BTC box.

Note: Equipment which is preinstalled within the above assembly is as follows :

  • Size: 3-1/2" EU 8rd Box x Pin Pup Joint
  • Swivel sub w / 3 1/2" Eu 8rd Box x Pin.
  • Size: 190-60 Baker Tubing Seal Nipple w/ X Ea Seal Units w/ 3-1/2" EU 8rd Box x Pin
  • Model 'S-1' shifting tool, Size 190-60 w/ 3-1/2" EU 8rd Box x Pin
  • Pup Joint - 10ft, Size 3-1/2" EU 8rd Box x Pin
  • Model 'M.R.C.V.' Multi Reverse Circulating Valve w/ 3-1/2" EU 8rd Box x Pin
  • Pup Joint - 10ft, Size 3-1/2" EU 8rd Box x Pin
  • Model "BSC-R", Size 190-60 Rotational Locked Hydroset Adapter Kit w/ 3-1/2" EU 8rd Pin Down
  • Model "SC" Size 86 Balanced Hydraulic Setting Tool w/ 3 1/2" IF box up.
  • Pup joint - 3 1/2" IF Box x Pin

7. MU washpipe to 3-1/2" EU 8rd Inner String. Remove Safety Clamp from washpipe. RD Stripping  Table. MU Gravel Pack Packer and Extension to Seal Bore Extension. Hang Off Gravel Pack Packer and Extension using 3-1/2" Drill Pipe Slips.

8. MU Crossover to work string and RIH at a minimum of 10m/min to avoid swabbing. Fill pipe every 5 stands with clear filtered 1.15 SG NaCl brine during RIH. The check valve on bottom will prevent  fluid entry into the work string.

9. Break circulation every 500 meters.

10.Prior to running into the open hole section, note PU and SD weights. Carefully run into the open hole section and set down on TD. PU and position bullnose +/- 1 meter off bottom.

11.Install a full opening kelly cock on work string. RU circulating head, low torque valves, high pressure hoses and squeeze manifold, connect to HP pumping unit. Pressure test all lines to 345 bar.

Note: High pressure hoses must be off sufficient lengths to allow for +/- 10 meters of travel above the rig floor.

12.Displace the hole to 1.15 SG NaCl brine. Circulate 2 x open hole annular volume or until losses are observed.

13.Drop a 1-1/2" Steel Setting Ball. Pump ball onto seat at approx. 300 LPM.

14.With ball on seat, pressure up the work string as follows to set the packer :

  1. Pressure up to 75 bar, hold for 1 minute.
  2. Pressure up to 100 bar, hold for 1 minute.
  3. Pressure up to 140 bar, hold for 5 minutes.
  4. Pressure up to 170 bar, hold for 5 minutes.
  5. Pressure up to 200 bar, hold for 5 minutes. Bleed off pressure.

15.Verify Slip Anchoring by picking up 10-15 tonnes. Slack off 5 tonnes on packer. Mark pipe. This is the SQUEEZE Position.

16.PU to neutral weight. Close the annular preventer. Pressure up on annulus to 140 bar for 10 minutes to test packer from above and activate hydraulic release. Bleed off pressure. Open the annular preventer.

17.PU to verify release from packer. The following positions can be achieved by PU & SD :



Distance to Locator on Stinger - Final Space Out


Total Stroke Length - 190-60 Seal Assembly

7.75 METER

Total Stroke Length - 120-38 Circ. Seal Assy.

6.00 METER (correct for space out)

Minimum Stroke to Close Lower Sliding Sleeve

5.25 METER (correct for space out)

Minimum Stroke to Close Upper Sliding Sleeve

3.50 METER




SD 5-10 tonnes


PU +/- 1.00 METER


PU +/- 7.00 METER.



PU +/- 6.00 METER



SD 5-10 tonnes


PU +/- 6.00 METER





Note: Do not pick up more than 3 meters after locating. This might permanently close the lower  sliding sleeve out of function.

18.PU + / - 1 m and pump the following pills down the work string to displace excess LCM material out of the screen and open hole annulus. Blow Ball Seat at +/- 240 bars.Pump steel ball onto Hydro-    Trip Sub and Blow second ball seat at +/- 240 bars.

-   Circulate out excess LCM material in the annulus by circ.down the following fluids.

-   1 m3 of a viscous HEC prepad consisting of  7.5 Kg of W-300 HEC per cu. meter 1.15 SG  NaCl brine, sheared and filtered through 2 micron filters with 2 1/2 liter of W - 321 HCl acid  breaker added prior to pumping.

-   A volume of twice the annular / screen volume  ( +/- 8 m3 ) of Shellflo S gelled 15 % acetic acid of the following composition ( per cu. meter ):

745 liter NaCl brine ( 1.15 SG )

47.6 liter of Shellflo S liquid polymer

10 Kg A-121 EDTA Iron Sequestering Agent

5 liter A-100 Acid Corrosion Inhibitor

15 liter BCS III Clay Stabilizer

180 liter A-160 Acetic Acid

Final density will be 1.125 SG.

Displace with 1/2 m3 of HEC gel without breaker and follow with the  Shellflo S gelled 15%  Acetic Acid  to be squeezed later

19.Spot the acid across the interval (spot the spacer of HEC gel inside the bullnose to prevent acid from being left inside this assembly). PU +/- 7 meters. SD to SQUEEZE POSITION to permanently close the sliding sleeve. Pressure test to 210 Bar to verify closed sliding sleeve.

20.Soak for 1 hour with no hydrostatic applied to the formation. (tbg. and annulus isolated)

21.PU +/- 6 meters. Inject 50 liter per meter reservoir ( +/- 15 m3 ) viscosified acetic acid of the same composition as above (step 18 )into the formation through the pre-packed screens at a low rate of approximately 50 - 100 LPM to extend the contact time between the gelled acid and the mud filter cake.

Note: Maximum injection pressure is 50 bars at 50 LPM.

22.Set down work string to SQUEEZE POSITION. Cycle the M.R.C.V open by pressure up to 140 Bar and bleed back in cycles. The M.R.C.V. will open on the eighth cycle.

23.When open, inject again 50 liter per meter reservoir of 15 % Shellflo S gelled Acetic Acid  (composition as in Step 18 and 21 ) into the formation from top at a low rate (75 -150 LPM ) from start. Displace with 1 tubing volume of clean filtered 1.15 SG NaCl brine. Let it soak for 1 hour.

Note: The pump rate should not exceed 350 LPM or the M.R.C.V. will close. Increase the rate to  200 - 250 LPM once 1/2 of the total acid volume is left. Maximum injection pressure is 50 bars  at 50 LPM.

24.Close M.R.C.V. by increasing the rate to approx. 500 - 700 LPM.

25.P/U +/- 6 meters to close the Upper Sliding Sleeve. Observe no leak-off on the annulus to verify Upper Sliding Sleeve closed. If in doubt, pressure up on the annulus to 70 Bar to verify a closed sleeve.

26.Continue with another tubing volume of brine to get the acid away from the screens and spot  +/- 8 m3 PERFFLOW  sized calsium carbonate LCM material on the inside of the screens. Displace with clean filtered 1.15 SG NaCl brine. Carefully screen-out with max. 35 Bar differential pressure ( 15-   20 Bar pump pressure ). Too high screen-out may increase the risk of sticking the wash pipe.

The composition of this pill is as follows (per cubic meter ):

  • 885 Liter 1.15 S.G. NaCl brine
  • 60 Liter W-306 liquid viscosifier
  • 75 Kgs fine graded CaCO3
  • 75 Kgs medium graded CaCO3

27.PU to position bottom of washpipe +/- 50 meters above top of screens. Circulate bottom up across choke manifold and take a flow check.

28.The wellbore clean-up programme prior to the completion operation consists of three stages:

  • Surface lines and pit cleaning
  • Mud displacement/ removal by reverse circulating with brine.
  • Well cleaning by normal circulating until reached desired cleanliness.

Surface Lines And Pits Cleaning

Flush with seawater the complete mud return system (trip tank, flow line, gumbo box and the mud ditch) and the required number of mud pits to handle the brine. Use 5% A-308N-Well Cleaner in the seawater as required to clean the pits and circulate from one pit to another until a sufficient cleanliness has been achieved.

Also ensure that the relevant circulating lines from the brine pits to the well through the different lines, blowout preventer, centrifugal and high pressure pumps are cleaned of the chalk mud using seawater included 5% A-308N Well Cleaner.

If the lines are greasy or corroded the A-306N Pipe dope remover and acid may be required to properly clean the surface system.

When the surface system is clean put the brine containing detergents into a designated holding pit.


Mud Displacement/ Removal By Reverse Circulating

Displace the chalk mud and clean the well with the following washing fluids and circulating methods:

-   Close the lower pipe rams and line up for reverse circulating with the rig pumps.

-   4 m3 W-299 XC gelled brine using 7.5 kg/m3 with closed piperams and using reverse circulating  path with the rig pump.

-   Follow with 25 m3 of 1.15 SG NaCl brine containing 5% A-308N Well Cleaner using the rig pump.  Displace this detergent pill out of the well with clean 1.15 S.G. NaCl brine using the rig pump.

Divert the returning detergent pill to a holding mud pit through the mud return system.

Well Cleaning By Normal Circulation

-   Circulate 10m3 of weak 15% acetic acid (200 litre 80% concentrated acid per cubic meter) followed by 5m3 1.15 S.G. NaCl brine.

-   Circulate 4 m3 of 1/2 molar caustic solution (60 litre concentrate per cubic meter) followed by 1.15 S.G. NaCl brine to neutralise the acid.

-   Circulate 8 m3 of 2% A-309N flocculant pill.

Divert the returns of this pill to the same holding pit as before.

- Continue circulating 1.15 SG NaCl brine until a cleanliness of +/- 10 NTU is achieved. Finish the well cleaning operation by open the rams and take returns through the modified return flow system. Continue until the brine cleanliness comes down to +/- 10 NTU measured from the return flow.

-   Add W-328NP Oxygen Scavenger at 0.25-0.5 kg/m3 if oxygen corrosion turns out to be a problem.  Oxygen corrosion is identified by the brine turning reddish in colour. The oxygen level is monitored with the oxygen meter and should be below 200 ppb.

29.Displace the well to treated 1.15 S.G. Sodium Formate brine, of the following composition (per cu. meter), using a viscous HEC pill as a spacer. Formulation of 1 m3 Sodium Formate brine:

998 Litres of 1.15 S.G. B-650 Sodium Formate Brine.

1Litre W-318 NaOH

1.35 Litres B-641 Gluteraldehyde Biocide

1 kg W-327NP Ascorbic Acid (Oxygen Scavenger - add immediately prior to pumping).

The Oxygen concentration should be checked in a sample of brine and should be less than 200 ppm after 20 min.

30.Check the well stability before pulling out of the hole.


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