Determining the life span of an elastomer in a motor

Patent metadata

Field	Value
Publication number	US-10139326-B2
Application number	US-201615220269-A
Country	US
Kind code	B2
Filing date	Jul 26, 2016
Priority date	Jul 27, 2015
Publication date	Nov 27, 2018
Grant date	Nov 27, 2018

Abstract

A method for determining a remaining life span of an elastomer in a motor. The method includes running a downhole tool into a wellbore. The downhole tool includes a mud motor having a rotor and a stator. At least one of the rotor or the stator includes, or is at least partially made from, an elastomer. A number of cycles before the elastomer fails may be predicted. A number of cycles during a time period may be determined. A change in a remaining life span of the elastomer over the time period may be determined, based upon the number of cycles before the elastomer fails and the number of cycles during the time period.

First claim

What is claimed is:

1. A method for determining a remaining life span of an elastomer in a motor, comprising:
running a downhole tool into a wellbore, the downhole tool including a drill bit and a mud motor, the mud motor having a rotor and a stator, wherein at least one of the rotor or the stator has an elastomer;
predicting a number of cycles before the elastomer fails;
determining a number of cycles during a time period;
determining a change in a remaining life span of the elastomer over the time period, based upon the number of cycles before the elastomer fails and the number of cycles during the time period; and
varying a weight on the downhole tool in response to the remaining life span of the elastomer or varying a torque generated by the mud motor in response to the remaining life span of the elastomer.

2. The method of claim 1 , wherein predicting the number of cycles before the elastomer fails comprises referencing a library comprising a plurality of measured or simulated values, wherein each of the plurality of measured or simulated values represents a different number of cycles before the elastomer fails.

3. The method of claim 1 , further comprising determining the remaining life span of the elastomer at a time based upon a previously determined remaining life span of the elastomer and the change in the remaining life span of the elastomer over the time period.

4. The method of claim 1 , wherein the downhole tool further comprises a drill bit, and wherein the method further comprises varying a weight on the drill bit in response to the remaining life span of the elastomer.

5. The method of claim 1 , wherein the downhole tool further comprises a drill bit.

6. A method for determining a remaining life span of an elastomer in a motor, comprising:
running a downhole tool into a wellbore, the downhole tool including a mud motor, the mud motor having a rotor and a stator, wherein at least one of the rotor or the stator has an elastomer;
measuring a differential pressure across the mud motor;
measuring a temperature proximate to the mud motor;
determining a number of cycles before the elastomer fails based at least partially upon the differential pressure and the temperature; and
varying a weight on the downhole tool in response to the remaining life span of the elastomer or varying a flow rate of a fluid being pumped into the wellbore in response to the remaining life span of the elastomer.

7. The method of claim 6 , wherein determining the number of cycles before the elastomer fails includes selecting, from a library, one of a plurality of measured or simulated values based upon the differential pressure, the temperature, a type of drilling fluid in the wellbore, or a combination thereof, wherein each of the plurality of measured or simulated values represents a different number of cycles before the elastomer fails.

8. The method of claim 6 , further comprising measuring the flow rate of the fluid being pumped into the wellbore.

9. The method of claim 8 , further comprising determining a number of cycles during a time period based at least partially upon the flow rate.

10. The method of claim 9 , further comprising determining a change in a remaining life span of the elastomer over the time period, based upon the number of cycles before the elastomer fails and the number of cycles during the time period.

11. The method of claim 10 , further comprising determining the remaining life span of the elastomer at a time based upon a previously determined remaining life span of the elastomer and the change in the remaining life span of the elastomer over the time period.

12. The method of claim 11 , wherein the remaining life span of the elastomer at the time is determined without measuring a speed of the mud motor.

13. The method of claim 6 , wherein the downhole tool further comprises a drill bit, and wherein the method further comprises varying a weight on the drill bit in response to the remaining life span of the elastomer.

14. The method of claim 6 , wherein the downhole tool further comprises a drill bit.

15. A computing system comprising:
one or more processors; and
a memory system comprising one or more non-transitory computer-readable media storing instructions that, when executed by at least one of the one or more processors, cause the computing system to perform operations, the operations comprising:
predicting a number of cycles before an elastomer in a downhole tool fails;
determining a number of cycles during a time period;
determining a change in a remaining life span of the elastomer over the time period, based upon the number of cycles before the elastomer fails and the number of cycles during the time period; and
varying a weight on the downhole tool in response to the remaining life span of the elastomer or varying a flow rate of a fluid being pumped into a wellbore in response to the remaining life span of the elastomer.

16. The computing system of claim 15 , wherein predicting the number of cycles before the elastomer fails comprises referencing a library comprising a plurality of measured or simulated values, wherein each of the plurality of measured or simulated values represents a different number of cycles before the elastomer fails.

17. The computing system of claim 15 , wherein the operations further comprise determining the remaining life span of the elastomer at a time based upon a previously determined remaining life span of the elastomer and the change in the remaining life span of the elastomer over the time period.

18. The computing system of claim 15 , wherein the downhole tool comprises a drill bit, and wherein the operations further comprise varying a weight on the drill bit in response to the remaining life span of the elastomer.

19. The computing system of claim 15 , wherein the downhole tool comprises a drill bit.

20. The computing system of claim 15 , wherein the computing system is at least partially disposed within the downhole tool.

Assignees

• Schlumberger Technology Corp

Inventors

• Ba Samba
• Kolyshkin Anton

Classifications

• E21B4/02 Primary

  Fluid rotary type drives · CPC title

• G01N3/12 Primary

  Pressure testing · CPC title