Volume 37, Number 4, August 2019
|802 - 808
|23 September 2019
Nonlinear Self-Excited Vibration Mechanism for Under-Actuated Oil-Well Drilling System with Stick-Slip Vibration
School of Power and Energy, Northwestern Polytechnical University, Xi’an 710072, China
2 Beijing Power Machinery Institute, Beijing 100074, China
3 Systems Engineering Research Institute, China State Shipbuilding Corporation, Beijing 100094, China
4 Faculty of Electronic and Information Engineering, Xi'an Jiaotong University, Xi'an 710049, China
5 School of Astronautics, Northwestern Polytechnical University, Xi’an 710072, China
Exploration of oil or gas wells is usually carried out by using drilling system. When the kilometers of drilling system is externally disturbed, the drilling system is prone to undesired stick-slip vibration of the drill-string. The stick-slip vibration of the drill-string belongs to the nonlinear self-excited vibration. In order to study the vibration mechanism, the model for the nonlinear torque on the bit by using Karnopp friction model and the two degrees of freedom model for drilling system were established. The equivalent damping torque formula and the energy variation formula of the drilling system were proposed. The mechanism of the nonlinear self-excited vibration of the drilling system was explained. The simulation results indicated that the stick-slip vibration of the drill-string was caused by the negative value of the equivalent damping force of the drilling system. The equivalent damping torque made the positive work on the system, so that the system absorbed the vibration energy from the outside, which destroyed the stability of the system equilibrium point. The feedback effect in the speed of the drill-bit regulates the system energy to maintain constant vibration without attenuation. In each vibration cycle, the energy input by the system is equal to the energy dissipated by the system. The energy absorbed by the drilling system is mainly converted into the potential energy.
Key words: drill string / stick-slip vibration / equivalent damping force / self-excited vibration / energy
关键字 : 钻柱系统 / 黏滑振动 / 等效阻尼扭矩 / 非线性自激振动 / 能量
© 2019 Journal of Northwestern Polytechnical University. All rights reserved.
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