This work investigates the results of the first deployment in the industry of technology Z on an offshore drilling rig with a heavy top drive. The study uses a quantitative analysis of downhole data to confirm the benefits of Z.
Z expands the stick-slip free operating envelope and does not require tuning. Following a dozen or so Z land rig deployments since 2015, the technology was added to a heavy offshore rig, a newbuilt, with modern hi-end variable frequency drives that enable near-zero control loop latencies. A study validates the effectiveness of the system with downhole rotary speed data.
The Z system was used for multiple sections in the Barents Sea, where the overburden traditionally causes troublesome torsional vibrations. The users of the technology gave a positive feedback from their first experiences. This work aims to verify qualitative surface observations with a quantitative analysis of downhole data. Downhole sensors captured the dynamics of multiple locations in the drill string over the course of about 3 weeks. Stick-slip severity was quantified using downhole rotary speed data. Periods when Z was turned on were compared to periods when Z was turned off.
Number of Pages
Journal of Sound and Vibration (1005) 179(4), 647–668, ACTIVE DAMPING OF SELF-EXCITED TORSIONAL VIBRATIONS IN OIL WELL DRILLSTRINGS, J. D. JANSEN AND L. VAN DEN STEEN
Journal of Sound and Vibration 305 (2007) 432–456 A simplified model to explore the root cause of stick–slip vibrations in drilling systems with drag bits Thomas Richarda, Christophe Germayb, Emmanuel Detournay
International Journal of Non-Linear Mechanics Understanding root cause of stick–slip vibrations in deepdrilling with dragbits Yevhen Kovalyshen
NTNU, Master of Science in Engineering Cybernetics, Stick-Slip Prevention of Drill Strings Using Nonlinear Model Reduction and Nonlinear Model Predictive Control, Morten Krøtøy Johannessen Torgeir Myrvold
Arch Appl Mech (2012) 82:515–531, E. Kreuzer · M. Steidl, Controlling torsional vibrations of drill strings via decomposition of traveling waves
SPE/IADC-SPE-173037-MS, Recent Advances in Soft Torque Rotary Systems, Sicco Dwars
SPE-184658-MS A Comparison of Stick-Slip Mitigation Tools, Aage Kyllingstad
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