Suppressing torsional drill-string vibrations considering high- and low-frequency disturbances by model reference
Chengda Lu1, Hengyu Huang2, Hao Sun3
1School of Automation, China University of Geosciences, Wuhan, 430074, China; Hubei Key Laboratory of Advanced Control and Intelligent Automation for Complex Systems, Wuhan, 430074, China; Engineering Research Center of Intelligent Technology for Geo-Exploration, Ministry of Education, Wuhan, 430074, China; School of Future Technology, China University of Geosciences, Wuhan, 430074, China.
ISA Transactions
|December 24, 2025
Summary
This study introduces a novel method to suppress torsional drill-string vibrations by decoupling high- and low-frequency disturbances. The model reference adaptive control with equivalent-input-disturbance (MRAC-EID) method effectively reduces complex vibrations during drilling.
Area of Science:
- Mechanical Engineering
- Control Systems Engineering
- Petroleum Engineering
Background:
- Drill-string vibrations, particularly torsional ones, significantly impact drilling efficiency and equipment longevity.
- Existing vibration suppression methods often fail to differentiate and address distinct high- and low-frequency disturbances from bit-rock interaction and drill-string dynamics.
- A need exists for advanced control strategies that can effectively decouple and mitigate these multi-frequency disturbances.
Purpose of the Study:
- To develop and validate a novel torsional drill-string vibration suppression method.
- To specifically address and decouple high-frequency and low-frequency disturbances inherent in the drilling process.
- To enhance the robustness and effectiveness of vibration control in diverse geological formations.
Main Methods:
- Development of a torsional vibration model for the drill-string.
- Implementation of a control scheme combining Model Reference Adaptive Control (MRAC) for low-frequency disturbances and Equivalent-Input-Disturbance (EID) for high-frequency disturbances (MRAC-EID).
- Stability analysis of the proposed MRAC-EID control system.
Main Results:
- The MRAC method successfully suppressed state-dependent low-frequency bit-rock interaction disturbances.
- The EID method effectively mitigated higher-frequency disturbances arising from the drill-string's segment flexible characteristics.
- The MRAC-EID method demonstrated significant vibration suppression capabilities across various simulated and experimental formation conditions.
Conclusions:
- The developed MRAC-EID method provides an effective approach for torsional drill-string vibration suppression.
- Decoupling and addressing distinct frequency components of disturbances leads to superior vibration control.
- The method shows promise for improving drilling operations in challenging geological environments.
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