Stick-slip oscillation is a recognized and documented drilling dysfunction that reduces drilling performance and increase well costs. Stick-slip is a drilling phenomenon associated with the use of fixed cutter bits that use a shear cutting mode and exacerbated by non-optimal weight on bit (WOB) and rotations per minute (RPM) settings. The bit speed can vary drastically from fully stopped to twice the RPM setting (0-200%) during periods of stick-slip oscillation. This case study details the benefits of an automated stick-slip identification and mitigation system and service using surface measurements for an Operator drilling in a geographically diverse area. The stick-slip mitigation service was successfully used to increase ROP, reduce the drilling time, and improve bit performance.
Traditional methods of reducing stick-slip include varying the WOB and RPM set points by the driller, which requires the driller to identify the stick-slip occurrences and manually manipulate both settings. Inefficiencies are inherent to this process as the driller is unable to accurately quantify the magnitude of the stick-slip period and set the optimal drilling parameters. Additional inefficiencies are associated with this method relative to how quickly the driller reacts to the onset of stick-slip and the frequency these changes are made while drilling.
An automated system was added to identify and quantify the stick-slip severity and to manipulate the top drive RPM speed to mitigate the stick-slip in real time. A real-time service complimented the automated system through the delivery of specialized training, remote settings maintenance, performance monitoring, and streamlining knowledge transfer.