Apparatus and method for detecting poor hole cleaning and stuck pipe

1. A method for preventing a downhole tool from getting stuck in a wellbore, the method comprising:

monitoring an output of at least one friction sensing device including a friction receiving portion having a base and an extended portion extending from the base, the base having an outer surface flush with an outer surface of the downhole tool, and the extended portion having a sensor located on an outer radial side of the extended portion to detect a characteristic of a radially-facing surface of the extended portion, the output of the at least one friction sensing device including an output of the sensor; and

reducing the friction to prevent the tool from getting stuck based on determining that the output indicates a high-friction condition.

2. The method as in claim 1 , wherein reducing the friction comprises at least partially withdrawing the downhole tool from the wellbore.

3. The method as in claim 1 , wherein reducing the friction comprises removing at least a portion of friction producing components in the wellbore.

4. The method as in claim 3 , wherein the friction producing components comprise at least one of drilling mud and drill cuttings.

5. A tool for use in a wellbore, comprising:

a main body having an outer surface; and

at least one friction sensing device comprising a friction receiving portion including a base and an extended portion extending inwardly from the base, the base having an outer surface flush with the outer surface of the tool, and the extended portion having a sensor located on an outer radial side of the extended portion, the sensor configured to detect a characteristic of a radially-facing surface of the extended portion.

6. The tool as in claim 5 , wherein the sensor is a strain gage.

7. The tool as in claim 5 , wherein the friction sensing device is mounted to a drill collar of a drill string.

8. The tool as in claim 5 , comprising wired drill pipe.

9. The tool as in claim 5 , wherein the outer surface of the friction receiving portion comprises a hardfacing.

10. The tool as in claim 5 , wherein the base extends lengthwise along the outer surface of the tool and the extended portion extends from the base into the tool.

11. The tool as in claim 10 , wherein the friction sensing device includes a retaining body to retain the friction receiving portion therein, and

a fluid fills spaces between the extended portion and the retaining body.

12. The tool as in claim 11 , further comprising a membrane connecting ends of the base and the retaining body, the fluid being contained by the membrane.

13. The tool as in claim 11 , wherein the friction sensing device comprises a coating on at least a portion of the extended portion that reduces internal friction between the extended portion and the retaining body.

14. The tool as in claim 13 , wherein the friction reducing coating is at least one of: a carbon coating, a diamond coating and a polytetrafluorethylene (PTFE) coating.

15. The tool as in claim 11 , further comprising:

a protrusion between the base and the extended portion to contact the retaining body; and

a disk between the extended portion and the retaining body,

wherein the friction receiving portion is retained in the retaining body by the protrusion and the disk.

16. The tool as in claim 10 , further comprising a disk between the extended portion and the retaining body.

17. The tool as in claim 10 , wherein the friction receiving portion is shaped substantially as a “T”, the base being a top of the “T” and the extended portion being a trunk of the “T”.

18. The tool as in claim 5 , wherein the sensor comprises a piezo force sensor.

19. The tool as in claim 5 , wherein the sensor is a distance measuring device.

20. The tool as in claim 19 , wherein the distance measuring device is at least one of: an ultrasonic transducer, a capacitive sensing device and a potentiometer.

21. A computer program product comprising machine readable instructions stored on machine readable media, the instructions for notifying a user of friction on a downhole tool, by implementing a method comprising:

receiving output from at least one friction sensing device a base and an extended portion extending from the base into the downhole tool, the base including a friction receiving portion having an outer surface flush with an outer surface of the downhole tool, and the extended portion including a sensor located on an outer radial side of the extended portion to detect a characteristic of a radially-facing surface of the extended portion, the output of the at least one friction sensing device including an output of the sensor; and

notifying the user of the friction sensed.

22. The computer program product as in claim 21 , further comprising instructions for determining if friction sensed by the at least one friction sensor exceeds a threshold value.

23. A friction sensing device, comprising:

a retaining body;

a friction receiving portion retained by the retaining body, the friction receiving portion comprising a base having an outer surface facing out from the retaining body to receive friction and an extended portion extending into the retaining body from the outer surface; and

a sensor located within the retaining body to detect characteristics of an outer radially-facing surface of the extended portion to sense friction on the outer surface of the base.