Patent ID: 9650880
Date: 2017-05-16
CPC Classifications: E21B

Claim:
1. A system for rotating a drill string, comprising: a drive system configured to rotate the drill string through variable angular displacements and at variable rotation speeds based on control signals received by the drive system; and a control system configured transmit the control signals to the drive system, wherein the control system is configured to generate the control signals based on pipe characteristics within the drill string and static friction values along the drill string to establish a rotation pattern of the drive system to approach a desired effective reach of surface torque generated by the drive system on the drill string, wherein the control system is configured to generate the control signals to comprise a velocity profile along which the drive system rotates the drill string, and wherein the velocity profile comprises a series of target rotational velocities over a time period, such that the drive system follows the velocity profile to facilitate propagation of a waveform to the desired effective reach along the drill string.