Blowout preventer blade assembly and method of using same
A blade assembly of a blowout preventer for shearing a tubular of a wellbore penetrating a subterranean formation is provided. The blowout preventer has a housing with a hole therethrough for receiving the tubular. The blade assembly includes a ram block movable between a non-engagement position and an engagement position about the tubular, a blade carried by the ram block for cuttingly engaging the tubular, a retractable guide carried by the ram block and slidably movable therealong, and a release mechanism for selectively releasing the guide to move between a guide position for guiding engagement with the tubular and a cutting position a distance behind the blade for permitting the blade to cuttingly engage the tubular.
1. A blade assembly of a blowout preventer for shearing a tubular of a wellbore penetrating a subterranean formation, the blowout preventer having a housing with a hole therethrough for receiving the tubular, the blade assembly comprising:
a ram block movable between a non-engagement position and an engagement position about the tubular;
a blade carried by the ram block to cuttingly engage the tubular;
a retractable guide carried by the ram block and slidably movable therealong, the retractable guide having a guide surface guidingly engageable with the tubular; and
a release mechanism to selectively release the retractable guide to move along the ram block, the release mechanism comprising a latch operatively connectable to the retractable guide.
2. The blade assembly of claim 1 , wherein the release mechanism is activatable by application of a disconnect force to the guide surface thereof.
3. The blade assembly of claim 1 , further comprising a trigger for activating the release mechanism.
4. The blade assembly of claim 3 , wherein the trigger comprises a plunger operatively connectable to the release mechanism.
5. The blade assembly of claim 4 , wherein the plunger is positioned about one of an apex of the guide, along the guide surface of the guide, and combinations thereof.
6. The blade assembly of claim 4 , wherein the plunger comprises a plurality of contacts, each of the plurality of contacts operatively coupled to a member by a rod, the member slidably positionable in a trigger channel of the guide.
7. The blade assembly of claim 4 , wherein the plunger has at least one trigger guide slidably positionable in at least one trigger slot in the guide.
8. The blade assembly of claim 3 , wherein the release mechanism comprises a member operatively coupled to the trigger and slidably positionable in a trigger channel of the guide.
9. The blade assembly of claim 8 , wherein the release mechanism further comprises a plurality of biasing members for supporting the member in the guide channel.
10. The blade assembly of claim 8 , wherein the release mechanism further comprises a plurality of wedges selectively movable between a locked and unlocked position in the guide by movement of the member.
11. The blade assembly of claim 10 , further comprising a plurality of bosses carried by the wedges and selectively movable along a plurality of passageways in the guide.
12. The blade assembly of claim 11 , wherein the passageways are in fluid communication with tubes extending through the guide for the passage of fluid therethrough.
13. The blade assembly of claim 2 , wherein the release mechanism comprises a lip positionable adjacent an edge of the ram block.
14. The blade assembly of claim 13 , wherein the ram block has a ramp for slidingly receiving the lip.
15. The blade assembly of claim 1 , wherein the guide comprises a plurality of springs and the release mechanism comprises a plurality of latches releaseably connectable to the plurality of springs.
16. The blade assembly of claim 15 , wherein the plurality of latches are pivotally connectable to the ram block for selectively engaging the plurality of springs.
17. The blade assembly of claim 1 , wherein the ram blocks have guide pins receivable by guide slots in the guide for sliding movement therealong.
18. The blade assembly of claim 1 , wherein the ram blocks have shoulders for slidable engagement with the guide.
19. The blade assembly of claim 1 , wherein the guide surface is concave with an apex along a central axis thereof.
20. The blade assembly of claim 1 , wherein the guide surface has a first portion at a first angle to the central axis.
21. The blade assembly of claim 20 , wherein the guide surface has a second portion at a second angle to the central axis.
22. A blowout preventer for shearing a tubular of a wellbore penetrating a subterranean formation, the blowout preventer comprising:
a housing with a hole therethrough for receiving the tubular; and
a pair of blade assemblies, each of the pair of blade assemblies comprising:
a ram block movable between a non-engagement position and an engagement position about the tubular;
a blade carried by the ram block to cuttingly engage the tubular;
a retractable guide carried by the ram block and slidably movable therealong, the retractable guide having a guide surface guidingly engageable with the tubular; and
a release mechanism to selectively release the retractable guide to move along the ram block, the release mechanism comprising a latch operatively connectable to the retractable guide.
23. The blowout preventer of claim 22 , wherein the retractable guide has a pocket for receiving a tip of another retractable guide positioned opposite thereto.
24. The blowout preventer of claim 22 , further comprising at least one actuator for actuating the ram block of each of the plurality of blade assemblies.
25. The blowout preventer of claim 22 , wherein the release mechanism comprises a trigger for activation thereof.
26. The blowout preventer of claim 23 , wherein the trigger is activatable upon contact with the tubular.
27. The blowout preventer of claim 23 , wherein the trigger is activatable upon contact with another guide.
28. A method of shearing a tubular of a wellbore penetrating a subterranean formation, the method comprising:
providing a blowout preventer, comprising:
a housing with a hole therethrough to receive the tubular; and
a pair of blade assemblies, each of the pair of blade assemblies comprising:
a ram block;
a blade carried by the ram block;
a retractable guide carried by the ram block; and
a release mechanism comprising a latch operatively connectable to the retractable guide;
moving the ram block between a non-engagement position and an engagement position about the tubular;
selectively releasing the retractable guide with the release mechanism;
slidably moving the guide along the ram block; and
cuttingly engaging the tubular with the blade.
29. The method of claim 28 , wherein the selectively releasing occurs on application of a disconnect force.
30. The method of claim 28 , wherein the selectively releasing comprises shifting a lip along a ramp of the ram block.
31. The method of claim 28 , wherein the selectively releasing comprises unlatching the retractable guide.
32. The method of claim 28 , wherein the selectively releasing comprises triggering the release mechanism.
33. The method of claim 28 , wherein the selectively releasing comprises shifting the release mechanism between a locked and an unlocked position.
34. The method of claim 28 , further comprising guiding the tubular to a desired position in the blowout preventer with the retractable guide.
35. The blade assembly of claim 1 , wherein the retractable guide is positionable in a guide position with the guide surface engageable with the tubular.
36. The blade assembly of claim 1 , wherein the retractable guide is positionable in a cutting position with a tip of the blade extending a distance further than the guide surface toward the tubular such that the blade is cuttingly engageable with the tubular.
37. The method of claim 28 , further comprising moving the retractable guide to a cutting position such that a tip of the blade extends a distance further toward the tubular than the retractable guide.