Claims
- 1. In a wellhead assembly having a production tree with a bore into which a tubing hanger lands and is sealed by tubing hanger seals, the tubing hanger adapted to be connected to a string of tubing, defining a tubing annulus, the tubing hanger having an axial passage with a lateral production port that registers with a lateral production passage in the tree for the flow of production fluid from the tubing, the improvement comprising:
a first portion of a tubing annulus passage extending upward through a portion of the tree from the tubing annulus to an exterior port, the port adapted to be connected to a source of gas for injection into the tubing annulus; a second portion of the tubing annulus passage extending upward through a portion of the tree from the external port to the bore of the production tree above the tubing hanger seals; a lower valve in the first portion of the tubing annulus passage for selectively opening and closing the first portion of the tubing annulus passage; the bore above the tubing hanger being free of any seals, exposing the tubing hanger above the tubing hanger seals to ambient pressure that exists externally of the tree; and two closure members located in the second portion of the tubing annulus passage in series with each other, for selectively opening and closing the second portion of the tubing annulus passage.
- 2. The wellhead assembly according to claim 1, wherein at least one of the closure members comprises a valve.
- 3. The wellhead assembly according to claim 1, wherein both of the closure members comprise valves.
- 4. The wellhead assembly according to claim 3, wherein:
the tree has a tubular mandrel that extends above the tubing hanger; the second portion of the tubing annulus passage has an axial portion that extends upward within a sidewall of the mandrel and a lateral portion that leads from the axial portion to the bore of the tree adjacent an upper end of the tree; and one of the valves is mounted in the axial portion and movable between a closed position, blocking flow between the axial and lateral portions, and an open position, allowing flow between the axial and lateral portions.
- 5. The wellhead assembly according to claim 1, wherein one of the closure members comprises a valve and the other comprises a removable plug.
- 6. The wellhead assembly according to claim 5, wherein:
the tree has a tubular mandrel that extends above the tubing hanger; the second portion of the tubing annulus passage has an axial portion that extends upward within a sidewall of the mandrel and a lateral portion that leads from the axial portion to the bore of the tree adjacent an upper end of the tree; and the plug is located in the lateral portion.
- 7. The wellhead assembly of claim 1, further comprising:
a pair of removable plugs landed within the axial passage of the tubing hanger above the lateral production port; a tubing hanger vent passage extending from the axial passage of the tubing hanger between the plugs to an exterior portion of the tubing hanger; and a tree vent passage registering with the tubing hanger vent passage for venting trapped fluid between the plugs.
- 8. The wellhead assembly of claim 1, further comprising:
a secondary lockdown assembly secured to a profile in the bore of the tree above the tubing hanger, the lockdown assembly having an axial passage therethrough and an upward protruding neck with an exterior profile on the neck; and a riser connector selectively coupled to the exterior profile on the neck for providing access to the axial passage of the tubing hanger.
- 9. In a wellhead assembly having a production tree with a mandrel having a bore into which a tubing hanger lands and is sealed by tubing hanger seals, the tubing hanger adapted to be connected to a string of tubing, defining a tubing annulus, the tubing hanger having an axial passage and a lateral production port that registers with a lateral production port in the tree for the flow of production fluid from the tubing, the improvement comprising:
a tubing annulus passage extending upward through a portion of the tree from the tubing annulus, the tubing annulus passage having an upper portion that is located within a sidewall of the mandrel and leads into the bore adjacent an upper end of the mandrel; and a closure member located in the upper portion of the tubing annulus passage adjacent the upper end of the mandrel for selectively opening and closing the upper portion of the tubing annulus passage.
- 10. The wellhead assembly of claim 9, wherein the closure member comprises a valve.
- 11. The wellhead assembly of claim 9, wherein the closure member comprises a removable plug.
- 12. The wellhead assembly of claim 9, wherein:
the upper portion of the tubing annulus passage has an axial portion parallel to an axis of the bore and a lateral portion that is inclined upward relative to a plane perpendicular to the axis of the bore, the lateral portion leading into the bore; and the closure member comprises a removable plug located with the lateral portion.
- 13. The wellhead assembly of claim 12, further comprising a corrosion cap located on an upper end of the mandrel, the corrosion cap having an aperture and an inclined guide aligned with the lateral portion; and wherein
the plug extends through the aperture and along the guide for insertion and removal from the lateral portion while the corrosion cap remains on the upper end of the mandrel.
- 14. The wellhead assembly of claim 9, wherein the closure member comprises an upward-biased valve that has a stem that protrudes above a rim of the mandrel while the valve is in a closed position, the stem adapted to be contacted by a riser connector to move the valve downward to an open position.
- 15. The wellhead assembly of claim 14, further comprising a corrosion cap that fits over the mandrel, the corrosion cap having a hole therethrough for receiving the stem.
- 16. The wellhead assembly of claim 9, wherein:
the tubing annulus passage has a first portion leading from the tubing annulus to an external port, the external port adapted to be connected to a source of injection gas; a lower end of the upper portion of the tubing annulus passage joins the external port; and a valve is located in the upper portion of the tubing annulus passage adjacent the lower end.
- 17. The wellhead assembly of claim 9, further comprising:
a pair of removable plugs landed within the axial passage of the tubing hanger above the lateral production port; a tubing hanger vent passage extending from the axial passage of the tubing hanger between the plugs to a lateral exterior portion of the tubing hanger; and a tree vent passage registering with the tubing hanger vent passage in the bore of the tree.
- 18. The wellhead assembly of claim 9, further comprising:
a lockdown assembly secured without seals to a profile in the bore of the tree above the tubing hanger, the lockdown assembly having an axial passage therethrough and an upward protruding neck with an exterior profile on the exterior of the neck; and a riser connector selectively coupled to the exterior profile on the lockdown assembly for providing workover access to the axial passage of the tubing hanger.
- 19. In a wellhead assembly having a production tree with a mandrel having a bore into which a tubing hanger lands and is sealed by tubing hanger seals, the tubing hanger adapted to be connected to a string of tubing, defining a tubing annulus, the tubing hanger having an axial passage and a lateral production port that registers with a lateral production port in the tree for the flow of production fluid from the tubing, the improvement comprising:
at least one plug landed within the axial passage of the tubing hanger above the lateral production port; a closure member located above said at least one plug for providing a second safety barrier for the axial passage of the tubing hanger; a tubing hanger vent passage extending from the axial passage of the tubing hanger between the plug and the closure member through the tubing hanger to an exterior portion of the tubing hanger; and a tree vent passage registering with the tubing hanger vent passage in the bore of the tree.
- 20. The wellhead assembly according to claim 19, further comprising a seal extending concentrically around the tubing hanger vent passage on the exterior portion of the tubing hanger for sealing around the tree vent passage.
- 21. The wellhead assembly according to claim 19, wherein the closure member comprises a second plug sealingly landed in the axial passage of the tubing hanger above said first mentioned plug; and wherein the wellhead assembly further comprises a tubing annulus passage extending through a portion of the tree from the tubing annulus to the bore of the tree above the tubing hanger seals, the bore of the tree above the tubing hanger seals being open to ambient pressure existing on the exterior of the tree.
- 22. The wellhead assembly according to claim 19, wherein:
the closure member comprises an internal tree cap located in the bore of the tree above the tubing hanger and sealed to the bore of the tree by an internal tree cap seal; and the wellhead assembly further comprises a tubing annulus passage extending through a portion of the tree from the tubing annulus to the bore of the tree above the internal tree cap seal, the bore of the tree above the internal tree cap seal being open to ambient pressure existing on the exterior of the tree.
- 23. In a wellhead assembly having a production tree with a mandrel having a bore into which a tubing hanger lands and is sealed by tubing hanger seals, the tubing hanger having an axial passage and a lateral passage leading therefrom for production flow, the improvement comprising:
a secondary lockdown assembly secured to a profile in the bore of the tree above the tubing hanger for preventing upward movement of the tubing hanger, the lockdown assembly having an axial passage therethrough that aligns with the axial passage of the tubing hanger, the lockdown assembly having an upward protruding neck with an exterior profile on the exterior of the neck; a riser connector selectively coupled to the exterior profile on the lockdown assembly for providing access to the axial passage of the tubing hanger; and wherein the bore above the tubing hanger is free of any seals so as to expose the tubing hanger above the tubing hanger seals to ambient pressure that exists on the exterior of the tree.
- 24. The wellhead assembly according to claim 23 wherein the riser connector has a tubular stinger that passes through the axial passage of the lockdown assembly and sealingly engages the axial passage of the tubing hanger.
- 25. The wellhead assembly according to claim 23 wherein the riser connector has a portion that has a diameter larger than a diameter of the bore of the tree.
- 26. A method of injecting gas into a tubing annulus of a wellhead assembly having a production tree with a bore into which a tubing hanger lands and is sealed by tubing hanger seals, the tubing hanger being connected to a string of tubing, defining the tubing annulus, the method comprising:
(a) providing a first portion of a tubing annulus passage extending upward through a portion of the tree from the tubing annulus to an exterior port; (b) providing a second portion of the tubing annulus passage extending upward through a portion of the tree from the exterior port to the bore of the production tree above the tubing hanger seals; (c) providing a lower valve in the first portion of the tubing annulus passage and opening the lower valve; (d) closing the second portion of the tubing annulus passage with two closure members in series with each other; (e) exposing the tubing hanger above the tubing hanger seals to ambient pressure that exists on the exterior of the tree; and (f) injecting gas through the exterior port, which flows through the first portion of the tubing annulus passage into the tubing annulus.
- 27. The method according to claim 26, wherein step (d) comprises:
providing and closing a valve adjacent a lower end of the second portion of the tubing annulus passage; and inserting a plug into an upper end of the second portion of the tubing annulus passage where it joins the bore.
- 28. The method according to claim 26, wherein step (d) comprises:
providing and closing a valve adjacent a lower end of the second portion of the tubing annulus passage; providing a check valve in an upper end of the second portion of the tubing annulus passage; and biasing the check valve to a closed position.
- 29. A method of providing access to a tubing annulus in a wellhead assembly having a production tree with a mandrel having a bore into which a tubing hanger lands and is sealed by tubing hanger seals, the tubing hanger being connected to a string of tubing, defining the tubing annulus, the method comprising:
(a) providing a tubing annulus passage extending upward through a portion of the tree within a sidewall of the mandrel from the tubing annulus and into the bore above the tubing hanger seals; and (b) installing a closure member in the tubing annulus passage adjacent an upper end of the mandrel; then, for access to the tubing annulus, (c) opening the closure member.
- 30. The method according to claim 29, wherein step (b) comprises mounting a valve in the tubing annulus passage adjacent an upper end of the tubing annulus passage.
- 31. The method according to claim 29, wherein step (b) comprises inserting a plug into an upper end of the tubing annulus passage; and
step (c) comprises removing the plug.
- 32. The method according to claim 29, wherein:
step (a) comprises providing the tubing annulus passage with a lateral portion that is inclined upward relative to a plane perpendicular to the axis of the bore, the lateral portion leading into the bore; step (b) comprises inserting a removable plug into the lateral portion; and step (c) comprises removing the plug from the lateral portion.
- 33. The method according to claim 29, wherein:
the wellhead assembly has a corrosion cap located on an upper end of the mandrel; step (b) comprises providing the corrosion cap with an aperture and an inclined guide aligned with the lateral portion; and step (c) comprises inserting the plug through the aperture and along the guide into the lateral portion.
- 34. The method according to claim 29, wherein:
step (b) comprises installing in the tubing annulus passage an upward-biased valve that has a stem that protrudes above a rim of the mandrel while the valve is in a closed position; and step (c) comprises landing a riser connector on the rim, thereby pressing the stem downward to an open position.
- 35. A method of connecting a workover riser to a wellhead assembly having a production tree with a mandrel having a bore into which a tubing hanger lands and is sealed by tubing hanger seals, the tubing hanger having an axial passage and a lateral passage extending therefrom for production fluid flow, the tubing hanger having at least one removable plug in the axial passage above the lateral passage, the improvement comprising:
securing a lockdown assembly to a profile in the bore of the tree above the tubing hanger, the lockdown assembly having an axial passage therethrough and an upward protruding neck with an exterior profile on the exterior of the neck; exposing the tubing hanger above the tubing hanger seals to ambient pressure that exists on the exterior of the tree; connecting a riser to the exterior profile on the lockdown assembly; then removing the plug through the riser.
Parent Case Info
[0001] This application claims priority from the provisional application Serial No. 60/308,343, filed Jul. 27, 2001 entitled “Production Tree With Gas Injection Feature”.
Provisional Applications (1)
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Number |
Date |
Country |
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60308343 |
Jul 2001 |
US |