Anti-locking device for use with an arm system for logging a wellbore and method for using same
An anti-lock system, device and method for logging a wellbore are presented. The anti-lock system of a downhole tool preferably includes a first arm, a second arm, a pad, a swivel bearing between the first arm and the pad, and an anti-locking device. The first arm has an arm first end connected to the tool body of the downhole tool and an arm second end connected to a first end of the pad. The second arm has an arm first end connected to the tool body of the downhole tool and an arm second end connected to a second end of the pad. The swivel bearing between the first arm and the pad pivotally connects the first arm to the pad. The anti-locking device is coupled to the swivel bearing, and preferably includes an anti-lock biasing member for maintaining a connection between the first arm and the pad at the swivel bearing in an engaged position during normal logging and for allowing the connection to rotate toward a biased position when a binding force is encountered in the arm system.
1. An anti-lock system for use with a downhole tool for logging a wellbore having a wellbore wall and at least one subterranean formation thereabout, the anti-lock system comprising:
a first arm having an arm first end connected to a tool body of the downhole tool and an arm second end connected to a first end of a pad;
a second arm having an arm first end connected to the tool body of the downhole tool and an arm second end connected to a second end of the pad;
a swivel bearing between the first arm and the pad for pivotally connecting the first arm to the pad; and
an anti-locking device coupled to the swivel bearing, the anti-locking device having an anti-lock biasing member for maintaining a connection between the first arm and the pad at the swivel bearing in an engaged position during normal logging and for allowing the connection to rotate toward a biased position when a binding force is encountered in the arm system.
2. The anti-lock system of claim 1 , wherein the anti-lock biasing member is a leaf spring.
3. The anti-lock system of claim 2 , wherein the anti-lock biasing member couples to the first arm at a fixed connection.
4. The anti-lock system of claim 3 , further comprising a pivot pin connectable to a portion of the pad, wherein the pivot pin engages a portion of the anti-lock biasing member thereby biasing the connection toward the resting position.
5. The anti-lock system of claim 4 , further comprising an anti-lock slot configured to guide the pivot pin between the engaged position and the biased position.
6. The anti-lock system of claim 5 , wherein the pivot pin is coupled to a bearing engaged with the pad and the anti-lock slot is formed in a fork coupled to the first arm.
7. An arm system having an anti-locking device for use with a downhole tool for logging a wellbore having a wellbore wall and at least one subterranean formation thereabout, the anti-lock system comprising:
a downhole tool positionable in the wellbore;
at least one arm set extendable from the downhole tool, each of the at least one arm sets having at least one arm system, the at least one arm system comprising:
a first arm having an arm first end connected to a tool body of the downhole tool and an arm second end connected to a first end of a pad;
a second arm having an arm first end connected to the tool body of the downhole tool and an arm second end connected to a second end of the pad;
a swivel bearing between the first arm and the pad for pivotally connecting the first arm to the pad; and
an anti-locking device coupled to the swivel bearing, the anti-locking device having an anti-lock biasing member for maintaining a connection between the first arm and the pad at the swivel bearing in an engaged position during normal logging and for allowing the connection to rotate toward a biased position when a binding force is encountered in the arm system.
8. The arm system of claim 7 , further comprising a sliding shuffle attached to a first end of the second arm, and adapted to allow the second arm to translate along a longitudinal axis of the tool body.
9. The arm system of claim 7 , wherein each of the at least one arm sets further comprises a plurality of the arm systems azimuthally spaced around a radius of the downhole tool.
10. The system of claim 7 , wherein the at least one arm sets further comprises two arm sets spaced longitudinally along the downhole tool.
11. The system of claim 10 , wherein each of the at least one arm sets has four arm systems azimuthally spaced 90° apart.
12. A method for logging a wellbore with a downhole tool having an arm system with an anti-locking device, the wellbore having a wellbore wall and at least one subterranean formation thereabout, the method comprising:
deploying the downhole tool into the wellbore, the downhole tool having the arm system with the anti-locking device, the arm system with the anti-locking device comprising:
a first arm having an arm first end connected to a tool body of the downhole tool and an arm second end connected to a first end of a pad;
a second arm having an arm first end connected to the tool body of the downhole tool and an arm second end connected to a second end of the pad;
a swivel bearing between the first arm and the pad for pivotally connecting the first arm to the pad; and
an anti-locking device coupled to the swivel bearing, the anti-locking device having an anti-lock biasing member;
maintaining a connection between the first arm and the pad at the swivel bearing in an engaged position during normal logging with the anti-lock biasing member; and
measuring at least one downhole parameter with the pad.
13. The method of claim 12 , binding a portion of the arm system against an upset in the wellbore.
14. The method of claim 13 , further comprising overcoming an anti-lock biasing force.
15. The method of claim 14 , further comprising rotating the connection toward a biased position when the anti-lock biasing force is overcome.
16. The method of claim 15 , wherein rotating the connection further comprising unbinding the arm system.