초록 ▼

A tubing assembly including a tubing string and tubing hanger provides a fluid passage with backpressure threads for securing a backpressure plug in a fluid-tight seal below the tubing hanger, so that the tubing hanger can be removed from the tubing string. The back pressure threads are preferably i

A tubing assembly including a tubing string and tubing hanger provides a fluid passage with backpressure threads for securing a backpressure plug in a fluid-tight seal below the tubing hanger, so that the tubing hanger can be removed from the tubing string. The back pressure threads are preferably incorporated in a backpressure adapter pin connected between the tubing string and the tubing hanger. The adapter pin may also incorporate external weight-bearing shoulders for snubbing and/or suspending the tubing assembly. The backpressure plug is inserted or removed using a backpressure plug tool that slides through a packing in a pressurized casement that maintains pressure in an axial passage through a control stack of the wellhead.

대표청구항 ▼

1. A method for removing a tubing hanger from a wellhead of a live well comprising steps of:inserting a backpressure plug in a backpressure adapter pin installed between the tubing hanger and a tubing string to seal the tubing string; connecting a landing joint to a top of the tubing hanger, and lif

1. A method for removing a tubing hanger from a wellhead of a live well comprising steps of:inserting a backpressure plug in a backpressure adapter pin installed between the tubing hanger and a tubing string to seal the tubing string; connecting a landing joint to a top of the tubing hanger, and lifting the tubing hanger and the tubing string from a tubing head spool of the wellhead by raising the landing joint; closing an annulus of the live well; supporting the tubing string below the tubing hanger; and removing the landing joint and the tubing hanger from the tubing string. 2. A method as claimed in claim 1 wherein the step of supporting comprises steps of:raising the tubing string a predetermined distance to align the adapter pin with slip blocks for supporting the tubing string; and closing the slip blocks around the adapter pin to support the tubing string. 3. A method as claimed in claim 1 wherein the step of closing the annulus comprises a step of closing annular rams of a blowout preventor to seal an annulus around the tubing string below the tubing hanger.4. The method as claimed in claim 1 wherein prior to inserting the backpressure plug into the adapter pin, the method further comprises steps of:mounting a backpressure plug tool to a top of a control stack of the well; balancing a fluid pressure between the well and an axial passage between the backpressure plug tool and a blocking point in the control stack beneath the backpressure plug tool; lowering the backpressure plug connected to the backpressure plug tool through the axial passage, the tubing hanger, and into a position above backpressure threads on an inner wall of the adapter pin; and securing the backpressure plug in the adapter pin. 5. The method as claimed in claim 4 further comprising a step of opening blind rams of a blowout preventor in the control stack.6. The method as claimed in claim 5 further comprising steps of:pulling the backpressure plug tool up above the blowout preventor; closing the blind rams after the backpressure plug is secured; and venting the axial passage above the blowout preventor to bleed off the fluid pressure in the axial passage. 7. The method as claimed in claim 6 further comprising steps of:removing the backpressure plug tool from the blowout preventor. 8. The method as claimed in claim 7 further comprising a step of connecting an adapter flange to the blowout preventor.9. The method as claimed in claim 8 further comprising a step of mounting a slip spool to the adapter flange.10. The methed as claimed in claim 9 further comprising a step of mounting and annular adapter to a top of the slip spool.11. The methed as claimed in claim 10 further comprising steps of sealing and pressure balancing the slip spool and the annular adapter before lowering the landing joint down through an axial passage and into a tubing spool.12. The method as claimed in claim 11 further comprising a step rotating thelanding joint to engage box threads in a top of the tubing hanger to connect the landing joint to the tubing hanger. 13. A method for inserting a tubing hanger into a tubing head spool of a live well comprising steps of:installing a backpressure plug in a top of a tubing string supported using slips located above a blowout preventor that closes an annulus of the live well; connecting the tubing hanger to the tubing string; connecting a landing joint to a top of the tubing hanger, and lifting the tubing hanger and the tubing string to release the slips; lowering the landing joint and mounting an adapter spool to a top of a control stack of the live well, above the blowout preventor; pressure balancing the adapter spool; opening an annulus of the live well; and running the tubing hanger into the tubing head spool. 14. The method as claimed in claim 13 further comprising a step of rotating the landing joint to engage box threads in a top of the tubing hanger to connect the landing joint to the tubing hanger.15. The method as claimed in claim 13 further comprising step of:locking the tubing hanger in the tubing head spool; rotating the landing joint to disconnect the landing joint from the tubing hanger; and raising the landing joint above the blowout preventor. 16. The method as claimed in claim 15 further comprising steps of:closing blind rams of the blowout preventor; releasing well pressure from the control stack above the blowout preventor; and removing the adapter spool from the control stack. 17. The method as claimed in claim 16 further comprising steps of:mounting a backpressure plug tool to the control stack; pressure balancing the control stack above the blowout preventor; opening the blind rams of the blowout preventor and lowering the backpressure plug tool to remove the backpressure plug from the tubing string. 18. The method as claimed in claim 17 further comprising steps of:raising the backpressure plug tool above the blowout preventor; closing blind rams of the blowout preventor; and releasing well pressure from the control stack above the blowout preventor. 19. The method as claimed in claim 18 further comprising a step of removing the backpressure plug tool from the control stack.20. The method as claimed in claim 13 wherein supporting the tubing string using the slips comprises supporting the tubing string using a slip spool mounted to the control stack above the blowout preventor.