SHIELDING AN UNDERWATER WELLHEAD HUB

• US 3,601,188 A
• Filed: 05/19/1969
• Issued: 08/24/1971
• Est. Priority Date: 05/19/1969
• Status: Expired due to Term

• Current Assignee: Robert G. Mcglamery, Thomas W. Childers
• Original Assignee: Robert G. Mcglamery, Thomas W. Childers
• Inventors: Mcglamery, Robert G., Childers, Thomas W.
• Application Number:
  US04/825,613
• Time in Patent Office: 827 Days
• US Class Current: 166/351
• CPC Class Codes: E21B 33/035 specially adapted for underwater installations E21B33/043, E21B33/064, E21B33/076 take precedence

Abstract

Method and apparatus for protectively shielding the attachment hub of an underwater wellhead structure. Expansible means, mounted on a support member adapted to be inserted into the bore of an underwater wellhead structure, for shieldingly covering the attachment hub of such structure when the hub is exposed underwater, are installed in the bore before the hub is so exposed.

Claims

1. A shielding apparatus adapted for use in an underwater wellhead structure having a hub surrounding a bore comprising:

a. support means having first and second ends, the second end being adapted for insertion into the bore of an underwater wellhead structure below the hub thereof;

b. expansible shielding means secured to the first end of said support means and expandable to extend over said hub for shielding, when expanded, the upper end of said hub of said wellhead structure, and compressible to a position inwarDly of said bore; and

c. coupling means on said support means adapted to coact with means on a remotely operable tool to releasably lock said support means to said tool; and

d. securing means on said second end of said support means for securing said support means in said wellhead structure, whereby the expansible means will be positioned above the top of said hub when so secured.

2. The apparatus of claim 1 further comprised of means for equalizing pressure levels across said securing means on said second end.

3. The apparatus of claim 1 in which said support means further comprises means for resisting cocking of the support means in the wellhead structure.

4. The apparatus of claim 1 in which said expansible means is outwardly expandable to a generally conical configuration which substantially covers and protectively shields said hub.

5. The apparatus of claim 1 in which said coupling means is positioned on said support means to allow said expansible means to be urged inwardly of said hub by said too.

6. The apparatus of claim 1 in which said expansible means comprises:

outwardly biased means inwardly attached to said support means for outward extension to said position outside said support means on release of constraint imposed thereupon.

7. The apparatus of claim 1 in which said expansible means comprises rib means centrally attached to said support means and interconnected by web means for arcuately outward extension to said position outside said support means, and spring means operatively associated with said rib means to urge said rib means to said position on release of constraint imposed on said rib means.

8. A shielding apparatus adapted for use in an underwater wellhead structure having a hub surrounding a bore, comprised of:

a. elongated support means having first and second ends;

b. expansible shielding means secured to the first end of said support means and outwardly expandable to extend over said hub for shielding, when expanded, the upper end of said hub of said wellhead structure, and which is compressible to a position inwardly of said bore;

c. landing means on said second end of said support means for landing said support means in the bore of said wellhead structure so that said first end extends above said hub sufficiently to permit said expansible shielding means to expand to said configuration;

d. means connected to said support means above said landing means and shaped relative to the configuration of said bore to resist cocking of the landing means in said wellhead structure;

e. passage means in said support means for equalizing said pressure across said landing means;

f. coupling means connected to said support means adapted to coact with means in a remotely operable tool to releaseably lock said support means to said tool, said coupling means being in a position to allow said expansible means to be urged inwardly of said hub by said tool.

9. The apparatus of claim 8 in which said expansible shielding means comprises:

outwardly biased means inwardly attached to said support means for outward extension, on release of imposed constraint, to a generally conical configuration which substantially covers and protectively shields said upper end of said hub.

10. A shielding apparatus for protection of an underwater wellhead structure having a hub surrounding a bore, comprising:

a. an elongated standard having a base adapted to be secured within a wellhead structure below said hub so that the upper end of said standard is above said hub;

b. passage means across said base of said standard adapted to interconnect the bore of said wellhead structure above and below said base when said base is secured in said wellhead structure;

c. sleeve means surrounding said standard and secured at one end to said base, the other end of said sleeve means terminating below the upper end of said standard;

d. coupling means connected to the upward end of said standarD for releaseably coacting with a remotely operable tool; and

e. expansible shield mounted on the upper end of said standard below said coupling means so as to extend over said hub when expanded, including e1. rib means centrally attached to said support means and interconnected by web means for arcuately outward extension to said position outside said support means, and e2. spring means operatively associated with said rib means to urge said rib means to said position on release of constraint imposed on said rib means.

11. A method of installing a superstructure sealingly attachable to the hub of an underwater wellhead structure extending upwardly in a hub which surrounds a bore, said wellhead structure carrying in said bore shielding means including expansible means expanded to substantially cover and shieldingly protect said hub, comprising a. running said superstructure down onto said hub of said wellhead structure to compress said expansible means inwardly of said hub, b. removing said shielding means from said wellhead structure by b1. running a retrieving tool, capable of releaseably locking with coacting coupling means associated with said shielding means, down through said superstructure to releaseably lock said shielding means to said retrieving tool, and b2. withdrawing said retrieving tool upwardly through said superstructure.

12. The method of claim 11 in which said underwater wellhead structure is an underwater wellhead terminating in a casing housing having said hub and said superstructure sealingly attachable on said hub is a blowout preventer sealingly attachable on said casing housing.

13. The method of claim 11 in which said underwater wellhead structure is a blowout preventer and said superstructure sealingly attachable on said hub is a marine riser.

14. In a method of removing a first blowout preventer sealingly attached to a first casing housing which concentrically supports a second casing housing having a hub surrounding a bore, the improvement of protectably shielding the hub of the second casing housing during removal of the first blowout preventer from the first casing housing, comprising:

a. running shielding means including expansible means into the bore of said second casing with a running tool while maintaining said expansible means in a constrained, flexed state;

b. disengaging and withdrawing said running tool from said shielding means, said expansible means on release of the constraint imposed by said running tool expanding to contact the inner wall of said blowout preventer, and c. retrieving said first blowout preventer to allow said expansible means to expand so that its extremities substantially cover and shieldingly protect said hub.

15. In the underwater drilling of a well, in which a first blowout preventer sealingly attached to a first casing housing is removed and a second blowout preventer is subsequently sealingly installed on a second casing housing concentrically supported within said first casing housing, said second casing housing having a hub surrounding a bore, the improvement of protectively shielding the hub of the second casing housing during the removal of the first blowout preventer and the installation of the second blowout preventer, comprising the sequential steps of:

a. running shielding means including expansible means into the bore of said second casing with a running tool so that said expansible means extends above said hub, while maintaining said expansible means in a constrained, flexed state;

b. disengaging and withdrawing said running tool from said shielding means, said expansible means on release of the contraint imposed by said running tool expanding to contact the inner wall of said first blowout preventer;

c. retrieving said first blowout preventer to allow said expansible means to expand so that its extremities substantially cover and shieldingly protect said hub;

d. runnIng said second blowout preventer down onto the hub of said second casing housing to urge said expansible means inwardly of said hub;

e. sealingly attaching said second blowout preventer to said hub;

f. running a retrieving tool, capable of coating with coupling means associated with said shielding means, down through said second blowout preventer to releaseably lock said shielding means to said retrieving tool, and g. retrieving said shielding means from said second casing housing.

16. In an underwater wellhead structure having a hub surrounding a bore, a shielding apparatus comprising:

a. support means having first and second ends, the second end having securing means thereon for coacting with means in said wellhead structure to secure said support means in said wellhead structure;

b. expansible means secured to the first end of said support means and positioned above the top of said hub when said support means is secured in said wellhead structure, said expansible means being compressible to a position inwardly of said bore and expandable to extend over said hub for shielding, when expanded, the upper end of said hub of said wellhead structure; and

c. coupling means on said support means adapted to coact with means on a remotely operably tool to releasably lock said support means to said tool.

17. THe shielding apparatus of claim 16 further comprising:

means connected to said support means shaped relative to the configuration of said bore to resist cocking of the support means in the wellhead structure.

18. The shielding apparatus of claim 16 further comprising:

passage means in said support means for equalizing the pressure across said securing means on said second end.

19. In an underwater wellhead structure having a hub surrounding a bore, a shielding apparatus comprising:

a. support means having first and second ends, said second end having secured means thereon for coacting with means in said wellhead structure to secure said support means in said wellhead structure;

b. expansible means secured to the first end of said support means and positioned above the top of said hub when said support means is secured in said wellhead structure, said expansible means including means biased outwardly to extend, on release of imposed constraint, to a generally conical configuration which substantially covers and protectively shields said upper end of said hub;

c. coupling means on said support means adapted to coact with means on a remotely operable tool to releaseably lock said support means to said tool;

d. means connected to said support means shaped relative to the configuration of said bore to resist cocking of the support means in the wellhead structure; and

e. passage means in said support means for equalizing the pressure across said securing means on said second end.

20. A method of protectively shielding the hub of an underwater wellhead structure having a bore which the hub surrounds, comprising:

installing in said bore, before said hub is exposed under water, shielding means including constrained expansible means compressible to a position inwardly of said bore for shielding, when expanded, the upper end of said hub of said wellhead structure;

removing constraint from said expansible means; and

exposing said hub under water.

21. A method of protectively shielding the hub of an underwater wellhead structure having a bore which the hub surrounds, prior to installation of superstructure sealingly attachable to said hub, comprising:

a. running said wellhead structure into position with a running tool, said wellhead structure carrying shielding means including expansible means in said bore for shielding said hub when said running tool is disengaged and withdrawn from said structure, and b. disengaging and withdrawing said running tool from said wellhead structure to allow said expansible means to expand to substantially cover and shieldingly protect said hub.

22. The method of claim 21 in which said underwater wellhead structure is an underwater wellhead terminating in a casing housing having a hub.

23. The method of claim 21 in which said underwater wellhead structure is a blowout preventer.