Wellbore friction depth sounding by oscillating a drill string or casing

A method for determining friction in a borehole comprising:

• during drilling of the borehole, applying, by a drilling system, oscillatory angular movement at the top of a drill string or a casing in the drilling system;
• measuring, by the drilling system during the drilling of the borehole, a plurality of torques applied to the drill string at a plurality of times for a plurality of depths of the borehole;
• measuring, by the drilling system during the drilling of the borehole, a plurality of angular positions of the drill string or the casing;
• based on the measured plurality of torques and the measured plurality of angular positions, determining, by the drilling system during the drilling of the borehole, a plurality of friction values between the borehole and the drill string or the casing at the plurality of times for the plurality of depths of the borehole;
• and
• based on the determined plurality of friction values as a function of the respective plurality of depths, altering at least one operation of the drilling system, wherein altering the at least one operation of the drilling system comprises one or more of:
• optimizing a toolface control in sliding by adjusting an angular spindle position based on a friction coefficient in the borehole;
• identifying an increase in friction during drilling, correlating the increase in friction to a hole cleaning issue, stuck pipe, or tortuosity, and adjusting one or more drilling parameters to mitigate the hole cleaning issue, stuck pipe, or tortuosity;
• using the determined plurality of friction values to optimize a weight on bit and a rate of penetration, including increasing a block velocity upon determining an increase in the friction coefficient during drilling;
• or
• using the determined plurality of friction values to apply a modified torque on a bottom hole assembly during rotary drilling, including increasing the block velocity by an amount corresponding to a computed lost torque as a function of the friction coefficient.

A non-transitory computer-readable medium comprising instructions configured to cause a drilling system to:

• during drilling of a borehole, apply oscillatory angular movement at the top of a drill string or a casing in the drilling system;
• measure, during the drilling of the borehole, a plurality of torques applied to the drill string at a plurality of times for a plurality of depths of the borehole;
• measure, during the drilling of the borehole, a plurality of angular positions of the drill string or the casing at the plurality of times for the plurality of depths of the borehole;
• based on the measured plurality of torques and the measured plurality of angular positions, compute, during the drilling of the borehole, a plurality of friction values between a well bore and the drill string or the casing;
• and
• based on the determined plurality of friction values as a function of the respective plurality of depths, alter at least one operation of the drilling system, wherein the instructions configured to cause the drilling system to alter at least one drilling operation comprise instructions configured to cause the drilling system to perform one or more of:
• optimizing a toolface control in sliding by adjusting an angular spindle position based on a friction coefficient in the borehole;
• identifying an increase in friction during drilling, correlating the increase in friction to a hole cleaning issue, stuck pipe, or tortuosity, and adjusting one or more drilling parameters to mitigate the hole cleaning issue, stuck pipe, or tortuosity;
• using the determined plurality of friction values to optimize a weight on bit and a rate of penetration, including increasing a block velocity upon determining an increase in the friction coefficient during drilling;
• or
• using the determined plurality of friction values to apply a modified torque on a bottom hole assembly during rotary drilling, including increasing the block velocity by an amount corresponding to a computed lost torque as a function of the friction coefficient.