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7” Liner Contingency Planning

Unable to reach setting depth with liner

The liner hanger starts to set at approximately 1,400psi / (100 bar) differential pressure. Take care that circulation pressure does not exceed 900psi / (62 bar).

If it takes more than 900psi / (62 bar) pressure to circulate. Make sure that the Liner hanger is in tension before increasing the pump pressure above this value.

To wash liner through a tight spot the following steps are to be taken:

  1. Pick up string.
  2. Start circulation and check weight of string up and down. Watch pressure closely (keep somebody regulating the pump).
  3. Slowly start rotation. When circulation is established slowly lower string through the tight spot, making sure that circulation pressure stays below 900psi / (62 bar) pressure. Watch pressure and torque readings carefully.
  4. Do not slack off more than 40 Klbs (20 Tonnes) onto liner weight while rotating. If slack off weight is reached, work string up and down through tight spot and continue.

Liner setting Ball doesn’t seat

  1. Drop the Bronze ball
  2. Rapidly fluctuate the pump pressure to generate pressure surges at the ball seat.
  3. Set mechanically on bottom.

Liner setting Ball seat doesn’t shear

  1. Go to 80% of casing burst pressure = 8,500 psi / (600 bar)

  2. Pressure up and bleed off over 10 cycles

  3. Prepare a Contingency plan that should consider these main operations:

  • POOH and drill out shoe track.

  • Cement through the shoe with cement retainer or retrievable packer with a packer setting dogs sub higher in the string.

  • Consider setting ‘ZXP’ Liner Top Packer on a second trip using modified Packer Setting if scan liner is not run .

Liner running tool doesn’t release

  1. Ensure tool is in compression of 20 klbs (10 tonnes) minimum when putting in turns and repeat left hand rotation cycles.

  2. Maintain left hand torque and work pipe between maximum string up weight (before hanger was set) and set down weight (after hanger was set)

  3. Continue working pipe while reciprocating.

  4. Leave workstring in tension and circulate.

  5. If nothing is solved, prepare a contingency plan that should consider these main operations:

  • Chemical Cut on DP

  • Fishing

Liner Plug does not bump

  1. It is important to ensure cement is not left within the latch couplings.
  2. Stop pumps at agreed displacement (e.g. 75% of total shoe track volume) and release setting tool.
  3. Pick up workstring and set ‘ZXP’ Liner Top Packer as per procedure.

Losses are observed during liner cement job

  • Reduce flow rate (considering Thickening time).

  • Set ZXP Liner Packer anyway and continue as per programme.

Liner Packer setting dogs do not engage top of tieback extension

  • Pick up workstring to point where dog subs are exposed above the tieback extension.

  • Set down again.

  • Pick up workstring and rotate drill string to free any cement from around dogs.

  • Set down again.

  • If engagement is still not possible, circulate to clean dogs.

  • Re attempt to set.

  • Still no success. POOH, Set ZXP Liner Top Packer on second trip with modified Packer Setting Sub or tie back packer if scab liner is not run.

ZXP Liner top packer fails positive pressure test

  • Attempt to fully set packer on second trip with modified Packer Setting Sub.

  • If pressure test is negative and leak at liner top is suspected, a contingency liner top isolation packer will be installed if scab liner is not run. Separate detailed procedure for this contingency operation will be prepared in due time.

ZXP liner packer setting procedure

  1. Pick up +/- 3m to locate mechanical setting dogs on top of Tieback Extension.

  2. Slack-off minimum 10 Klbs (5 tonnes) and mark the pipe. Continue to slack off weight for a minimum of 50Klbs. Monitor weight indicator for shear indication (two shears may be observed). Hold for 5 minutes to ensure complete setting of packer.

  3. Pick up to up weight and set down 10Klbs. Observe mark on pipe. If mark has moved down approx 9”, this is an indication of the packer functioning.

  4. Do not perform any annular pressure test at this stage.

  5. Pressure up drill pipe to 500 psi (35 bar) and pull running tool inside PBR and Long Way circulation whilst inside the PBR.

NOTE:  String to be pulled slowly due to observe the pressure loss to indicate the RPB pack off bushing has been retrieved from ‘RS’ seal bore.

Lay down plug dropping head and POOH.