Investigating the DRCAT Algorithm as a Solution to Auto-Driller Dysfunction and Automatic Tuning

Abstract

The effect of auto-driller behavior has started to more attention in literature (Pastusek et al. 2016). Dysfunction can occur when the bit transitions to a harder formation and if the control gain of the auto-driller’s P.I.D. controller is not adjusted, then instability in the system can occur. An algorithm has been tested as a solution to adjusting this control gain in real time (Badgwell et al. 2018). The behavior of the algorithm is as the authors desired when WOB mode is active for extended periods of time. When it is not, such as in shallow, surface drilling, then the algorithm has its fallbacks when it comes to increasing the control gain over time. On simulated data, there is significant improvement in the drum rotation speed of the drawworks, in terms of stability. There could be positive results for lateral drilling, but issues with weight transfer to the bit bring these into question.