Assisting retrieval of a downhole tool

1. A well tool comprising:

a well packer that comprises an expandable member that rides on a mandrel extending at least a portion of the well tool;

a hydraulic sub-assembly coupled to the well packer;

an anti-preset assembly coupled to the hydraulic sub-assembly;

a slip assembly coupled to the anti-preset assembly; and

a fold-back assembly coupled between the well packer and the hydraulic sub-assembly, the fold-back assembly comprising:

a bias member carried on the mandrel and adapted to engage a profile formed on the mandrel based on a setting stroke that adjusts the expandable member into an expanded position in substantially sealing contact with a tubular; and

a ring member carried on the mandrel adjacent the bias member.

2. The well tool of claim 1 , where the bias member is radially-biased inwardly toward the mandrel.

3. The well tool of claim 1 , where the ring member comprises one of:

a shear ring fixed to an adapter carried on the mandrel with a shear member;

a spring positioned between a shoulder of the adapter and the bias member; or

a moldable member positioned between a shoulder of the adapter and the bias member.

4. The well tool of claim 3 , where the shear member is adapted to shear in response to a force to initiate the setting stroke to adjust the expandable member into the expanded position, and an uphole surface of the bias member defines a no-go shoulder in the extended position.

5. The well tool of claim 3 , where the profile comprises a groove, and the spring maintains a substantially constant force on the bias member to urge the bias member into the groove.

6. The well tool of claim 3 , where the moldable member comprises a thermoplastic member comprising a glass transition temperature at or below a particular temperature in the well bore, the thermoplastic member adapted to transfer a force from the adapter to the snap ring when the particular temperature is below the glass transition temperature, the thermoplastic member adapted to flow through a bore in the adapter in fluid communication with the well bore when the particular temperature is above the glass transition temperature.

7. The well tool of claim 1 , where the bias member comprises a body lock ring, and the profile comprises a threaded surface adapted to engage the body lock ring.

8. The well tool of claim 1 , where the bias member moves independently of operation of the hydraulic sub-assembly and the anti-preset assembly when the expandable member is adjusted to the expanded position.

9. A well tool comprising:

a well packer that comprises an expandable member that rides on a mandrel extending at least a portion of the well tool;

a hydraulic sub-assembly coupled to the well packer;

an anti-preset assembly coupled to the hydraulic sub-assembly;

a slip assembly coupled to the anti-preset assembly; and

a fold-back assembly coupled between the well packer and the hydraulic sub-assembly, the fold-back assembly comprising a bias member carried on the mandrel and adapted to engage a profile formed on the mandrel based on a setting stroke that adjusts the expandable member into an expanded position in substantially sealing contact with a tubular, where the bias member is radially-biased inwardly toward the mandrel.

10. The well tool of claim 9 , where the fold-back assembly further comprises a ring member carried on the mandrel adjacent the bias member, and where the ring member comprises one of:

a shear ring fixed to an adapter carried on the mandrel with a shear member;

a spring positioned between a shoulder of the adapter and the bias member; or

a moldable member positioned between a shoulder of the adapter and the bias member.

11. The well tool of claim 10 , where the shear member is adapted to shear in response to a force to initiate the setting stroke to adjust the expandable member into the expanded position, and an uphole surface of the bias member defines a no-go shoulder in the extended position.

12. The well tool of claim 10 , where the profile comprises a groove, and the spring maintains a substantially constant force on the bias member to urge the bias member into the groove.

13. The well tool of claim 10 , where the moldable member comprises a thermoplastic member comprising a glass transition temperature at or below a particular temperature in the well bore, the thermoplastic member adapted to transfer a force from the adapter to the snap ring when the particular temperature is below the glass transition temperature, the thermoplastic member adapted to flow through a bore in the adapter in fluid communication with the well bore when the particular temperature is above the glass transition temperature.

14. The well tool of claim 9 , where the bias member comprises a body lock ring, and the profile comprises a threaded surface adapted to engage the body lock ring.

15. The well tool of claim 9 , where the bias member moves independently of operation of the hydraulic sub-assembly and the anti-preset assembly when the expandable member is adjusted to the expanded position.

16. A well tool comprising:

a well packer that comprises an expandable member that rides on a mandrel extending at least a portion of the well tool;

a hydraulic sub-assembly coupled to the well packer;

an anti-preset assembly coupled to the hydraulic sub-assembly;

a slip assembly coupled to the anti-preset assembly; and

a fold-back assembly coupled between the well packer and the hydraulic sub-assembly, the fold-back assembly comprising a bias member carried on the mandrel and adapted to engage a profile formed on the mandrel based on a setting stroke that adjusts the expandable member into an expanded position in substantially sealing contact with a tubular, where the bias member moves independently of operation of the hydraulic sub-assembly and the anti-preset assembly when the expandable member is adjusted to the expanded position.

17. The well tool of claim 16 , where the fold-back assembly further comprises a ring member carried on the mandrel adjacent the bias member, and where the ring member comprises one of:

a shear ring fixed to an adapter carried on the mandrel with a shear member;

a spring positioned between a shoulder of the adapter and the bias member; or

a moldable member positioned between a shoulder of the adapter and the bias member.

18. The well tool of claim 17 , where the shear member is adapted to shear in response to a force to initiate the setting stroke to adjust the expandable member into the expanded position, and an uphole surface of the bias member defines a no-go shoulder in the extended position.

19. The well tool of claim 17 , where the profile comprises a groove, and the spring maintains a substantially constant force on the bias member to urge the bias member into the groove.

20. The well tool of claim 17 , where the moldable member comprises a thermoplastic member comprising a glass transition temperature at or below a particular temperature in the well bore, the thermoplastic member adapted to transfer a force from the adapter to the snap ring when the particular temperature is below the glass transition temperature, the thermoplastic member adapted to flow through a bore in the adapter in fluid communication with the well bore when the particular temperature is above the glass transition temperature.

21. The well tool of claim 16 , where the bias member comprises a body lock ring, and the profile comprises a threaded surface adapted to engage the body lock ring.

22. The well tool of claim 16 , where the bias member is radially-biased inwardly toward the mandrel.