Auto-Driller Automatic Tuning

Abstract

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.

Adaptive Response Time for Integrated Autodriller Controller

“…Autodrillers are the commonly used tools in the drilling industry for WOB control by applying regulated force on the drill bit by means of a proportionalintegral (PI) controller. An industry-wide problem with autodrillers is maintaining regulation when drilling from one formation to another of different strength (Pastusek et al, 2016;Badgwell et al, 2018;Cayeux, 2018). This causes the error within the control loop to suddenly increase or decrease, resulting in controller instability.…”

“…(Pastusek et al, 2016) pointed out the coupling between incorrect autodriller regulation and the drill string stick-slip. Operator intervention is required to stabilize the regulation, either by changing the setpoint or gain of the con-troller (Pastusek et al, 2016;Badgwell et al, 2018;Adam, 2018). Therefore making the success of the process dependent on the operator's skills.…”

“…Adam (2018) collected autodriller parameters and corresponding ROP from successful drilling operations and created a road map intended to assist operators to select optimal autodriller parameters. Badgwell et al (2018) proposed to use the ROP setpoint to auto-adjust the WOB gain to respond to autodriller instabilities. In addition, Badgwell et al (2018) challenged autodriller vendors to address the WOB controller issues.…”

“…Badgwell et al (2018) proposed to use the ROP setpoint to auto-adjust the WOB gain to respond to autodriller instabilities. In addition, Badgwell et al (2018) challenged autodriller vendors to address the WOB controller issues. We accepted this challenge.…”