Autonomous connection evaluation and automated shoulder detection for tubular makeup

1. A method of connecting a first threaded tubular to a second threaded tubular, comprising:

engaging the threads of the tubulars;

rotating the first tubular relative to the second tubular to makeup a threaded connection;

during makeup of the threaded connection:

measuring time;

measuring torque applied to the connection; and

measuring turns of the first tubular; and

using a controller for:

evaluating at least one of the measured turns, the measured torque, and the measured time for discontinuities, wherein at least one discontinuity exists in at least one of the measured turns, the measured torque, and the measured time;

plotting the measured torque against the measured turns to create a torque-turns curve, wherein the at least one discontinuity is present in the torque-turns curve;

correcting the at least one of the measured turns, the measured torque, and the measured time to eliminate the at least one discontinuity and to smooth the torque-turns curve; and

accepting or rejecting the connection based on the evaluation.

2. The method of claim 1 , further comprising evaluating at least one of the measured turns, measured torque, and measured time for a lack of connection, comprising at least one of:

determining whether the measured turns of the first tubular are less than a minimum turns threshold; and

determining whether the measured torque is less than a minimum torque threshold.

3. The method of claim 1 , further comprising evaluating at least one of the measured turns, measured torque, and measured time for a torque spike comprising at least one of:

determining whether the torque spike exceeds a first torque threshold; and

determining whether the torque spike exceeds a second torque threshold within a time threshold.

4. The method of claim 1 , further comprising evaluating at least one of the measured turns, measured torque, and measured time for a torque drop comprising:

calculating a torque drop height from the measured torque by using start and end measured torque values of the torque drop; and

comparing the torque drop height to a torque drop threshold.

5. The method of claim 4 , wherein the torque drop height is calculated using an average of the start and end measured torque values.

6. The method of claim 1 , wherein the at least one discontinuity includes at least one of:

a change in measured torque at constant measured turns;

a change in measured turns at constant measured torque;

a decrease in measured turns; and

a decrease in measured time.

7. The method of claim 1 , further comprising:

analyzing at least one candidate for a shoulder position of the threaded connection; and

accepting or rejecting the connection based on the analysis.

8. The method of claim 1 , further comprising using the controller for:

finding at least one candidate for a shoulder position of the threaded connection from at least one of the measured torque and the measured turns;

analyzing the at least one candidate; and

detecting the shoulder position of the threaded connection based on the analysis.

9. The method of claim 8 , further comprising selecting the at least one candidate from the measured torque and measured turns.

10. The method of claim 8 , further comprising:

overlaying a circle at a start point on the torque-turns curve, wherein the torque-turns curve intersects the circle at a first point and a second point; and

measuring an angle between a first line between the start point and the first point and a second line between the start point and the second point.

11. The method of claim 8 , wherein finding the at least one candidate comprises:

overlaying a first line from a measured final torque value on the torque-turns curve to a point along the torque-turns curve;

overlaying a second line from a measured starting torque value on the torque-turns curve to the point; and

measuring an angle between the first line and the second line.

12. The method of claim 11 , further comprising determining the shoulder position of the connection based on the measured angle.

13. The method of claim 1 , wherein the at least one discontinuity results from a malfunction.

14. A tubular makeup system, comprising:

a power drive operable to rotate a first threaded tubular relative to a second threaded tubular;

a torque cell;

a turns counter; and

a controller operably connected to the power drive and in communication with the torque cell and turns counter, wherein the controller is configured to control an operation, the operation comprising:

engaging threads of the tubulars;

rotating the first tubular relative to the second tubular to makeup a threaded connection;

during makeup of the threaded connection:

measuring time;

measuring torque applied to the connection; and

measuring turns of the first tubular;

evaluating at least one of the measured turns, the measured torque, and the measured time for discontinuities, wherein at least one discontinuity exists in at least one of the measured turns, the measured torque, and the measured time;

plotting the measured torque against the measured turns to create a torque-turns curve, wherein the at least one discontinuity is present in the torque-turns curve;

correcting the at least one of the measured turns, the measured torque, and the measured time to eliminate the at least one discontinuity and to smooth the torque-turns curve; and

accepting or rejecting the connection based on the evaluation.

15. The system of claim 14 , the operation further comprising evaluating at least one of the measured turns, the measured torque, and the measured time for a lack of connection, comprising at least one of:

determining whether the measured turns of the first tubular are less than a minimum turns threshold; and

determining whether the measured torque is less than a minimum torque threshold.

16. The system of claim 14 , the operation further comprising evaluating at least one of the measured turns, the measured torque, and the measured time for a torque spike comprising at least one of:

determining whether the measured torque exceeds a first torque threshold; and

determining whether a spike in the measured torque exceeds a second torque threshold within a time threshold.

17. The system of claim 14 , the operation further comprising evaluating at least one of the measured turns, the measured torque, and the measured time for a torque drop comprising:

calculating a torque drop height from the measured torque by using start and end measured torque values of the torque drop; and

comparing the torque drop height to a torque drop threshold.

18. The system of claim 14 , the operation further comprising:

finding at least one candidate for a shoulder position of the threaded connection from at least one of the measured torque and measured turns;

analyzing the at least one candidate; and

detecting the shoulder position of the threaded connection based on the analysis.

19. The system of claim 14 , the operation further comprising:

finding at least one candidate for a shoulder position of the threaded connection from at least one of the measured torque and the measured turns, comprising:

overlaying a first line from a measured final torque value on the torque-turns curve to a point along the torque-turns curve;

overlaying a second line from a measured starting torque value on the torque-turns curve to the point; and

measuring an angle between the first line and the second line.

20. The system of claim 14 , wherein the at least one discontinuity results from a malfunction.

21. The system of claim 14 , wherein the at least one discontinuity includes at least one of:

a change in measured torque at constant measured turns;

a change in measured turns at constant measured torque;

a decrease in measured turns; and

a decrease in measured time.