engleski

SOFT DRIVE - A Torsional Vibration Active Damping System Equipped with Back-Spinning Prevention

Many contemporary oil drilling rigs are still equipped with mature drilling equipment such as traditional speed-controlled top-drive units. Utilization of such “stiffly” controlled drilling drives, which do not account for drill-string compliance-related tool stick-slip effect, may, in turn, shorten the useful life of the drilling tool and other drill-string drive mechanical components. The drilling performance of these mature rigs can be improved by the addition of advanced drill-string rotational dynamics controls aimed at active torsional vibration suppression, which can enhance the efficiency and productivity of the drilling process. These active damping control strategies typically emulate a passive absorber behavior by means of a robust single-loop drill-string PI speed controller tuned with respect to the drill-string drive resonant frequency. However, such a simple control strategy may not perform well under stuck tool conditions, resulting in hazardous back-spinning (back-lashing) drive behavior if proper drive stopping measures are not undertaken. Hence, the control strategy should be extended with a stuck tool condition detection system which unwinds the drill-string under speed control before it becomes dangerously strained, thus avoiding uncontrolled drilling drive behavior. This short communication outlines the novel design of the rotary drilling drive active damping control system resulting from joint retrofitting R&D between industry and the university.

Active damping ; torsional vibrations

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