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Conference papers

Impact of PDC Bit Design on Stick-Slip

Abstract : Drillstrings are affected by different types of harmful vibrations particularly stick-slip which is characterized by PDC drill bits intense rotary speed fluctuations. Based on laboratory drilling tests and numerical simulations, this paper aims at understanding the dynamics of the drill bit / rock interaction and assessing how stick-slip depends on bit design (bit profile and diameter, PDC‟s orientation, geometry and set up, ...). An extensive single cutter experimental program has shown that forces acting on PDC cutters strongly depend on cutter velocity for the four tested rocks. This rate effect is mainly due to the dynamic shearing of crushed rock carried away beneath the moving cutter. Based on these experiments, a semi-empirical rate-dependent cutter-rock interaction model is developed, implemented in a bit design software and used to predict the velocity signature of various PDC bits. These predictions fit well with numerous experimental results obtained using a full scale drilling bench. The model accounts for the negative damping effect (source of stick-slip instabilities) and for important operational trends related to stick-slip. The model developed has been used as the boundary condition of a drillstring vibration analysis software. Numerical simulations show that the bit design significantly impacts the risk of stick-slip. As a result, general optimization guidelines are suggested in order to design an "anti-stick-slip" drill bit.
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Conference papers
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Contributor : Pascale Nalon <>
Submitted on : Tuesday, July 24, 2012 - 11:39:14 AM
Last modification on : Thursday, September 24, 2020 - 4:34:05 PM


  • HAL Id : hal-00720322, version 1


Gilles Pelfrene. Impact of PDC Bit Design on Stick-Slip. SPE/STC 2010, Oct 2010, Wietze, Germany. ⟨hal-00720322⟩



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