Deployment of a Self-Adjusting Bit to Solve Todays Drilling Vibration Challenges and Optimize Performance

摘要

For well over a decade, we have been using depth-of-cut (DOC) control to control the aggressiveness of polycrystalline diamond compact (PDC) bits. In recent years, the ability to change the aggressiveness has been an effective way of mitigating vibrations, in particular for stick-slip. The amount of fixed DOC control is determined for a particular formation or DOC, but it can limit performance in other parts of the well, or not solve vibration problems in multiple formations. This paper demonstrates that having a PDC bit with innovative self-adjusting DOC control can mitigate these vibrations to enable improved performance through each section of the well. In the selected application in South Texas, torsional vibrations or stick-slip can be problematic, damaging the bit or downhole tools and reducing drilling performance. Performance metrics and dull conditions were collected to prove the presence of torsional dysfunction. Current bit styles have acceptable performance; however, the bit life has limitations regarding vibrations. Mitigating vibration is required to improve the performance of the bit and system. The addition of the self-adjusting DOC control feature changes the bit aggressiveness continually during the drilling operation, helping to achieve optimal performance. When the self-adjusting feature engages with rock for steady state drilling, the feature gradually retracts, controlling the DOC to find the optimal exposure of the element for the current drilling parameters and formations. As dynamic instabilities occur, the self-adjusting feature reacts at fast time scales to mitigate the event. Comparing this technology to the offsets, the drilling data at surface show improved performance with 196% distance drilled while the downhole data show there is a smooth drilling response throughout the run. A bit with the innovative self-adjusting DOC control can adapt to the downhole variables, prolonging its life and helping operators achieve their goals more efficiently, or with minimal driller intervention. Previously validating the concept in research wells it is now demonstrated in field trials with a reduction in torsional vibrations.