Auto-Driller Automatic Tuning

While drilling rig control systems have been deployed for many years, a 2016 study [1] identified significant room for improvement in three areas: auto-drillers, top drive torsional damping systems, and heave compensation systems. In particular, in a representative configuration the auto-driller Weight-On-Bit (WOB) controller can exhibit undesirable behavior, including instability, as the drill bit penetrates successive layers of rock with differing hardness. An unstable WOB controller may lead to inefficient drilling and bit damage, and can even induce stick-slip. It was shown, both by simulation and by tests on actual wells, that this behavior can be mitigated by appropriate adjustments to the WOB controller gain. In this paper we present a new algorithm, which we call Drilling Rig Automatic Control Tuning (DRCAT), designed to make these controller gain adjustments automatically. We challenge the auto-driller vendor community to either deploy the DRCAT algorithm or develop a better solution.