A modified model for friction reduction by vibrating drill-string longitudinally

作者：Wang Peng; Ni Hongjian^*; Wang Ruihe; Li Zhina

来源：Energy Education Science and Technology Part A: Energy Science and Research , 2014, 32(5): 2941-2950.

DOI：10.4028/www.scientific.net/amm.535.597

• Drill string vibrations
• Elastic-plastic contact
• Elliptical asperity
• Friction coefficients
• Friction reduction
• Influence factors
• Tangential stiffness
• Vibration frequency

<jats:p>Drill-string vibration excitation longitudinally is a potential drilling method for reducing friction between drill-string and borehole rock. This article assumes that borehole rock surface is composed of elliptical asperities, based on elastic-plastic contact theory, a modified model for friction reduction by vibrating drill-string longitudinally is developed. The results show that the tangential stiffness of borehole rock surface decreased with increasing ovality of asperity. Further, at the same ovality, thin and tall asperity has bigger tangential stiffness than short and fat asperity. Only when the tangential stiffness of borehole rock is greater than a certain threshold, the friction force calculated by proposed model in this paper can appear reverse phenomenon. When the tangential stiffness tends to infinity, the result tends to Coulomb model. The conclusions provide basis for research and application of drill-string vibration longitudinally friction reduction technology.</jats:p>

• 出版日期2014-11-1
• 单位中国石油大学（华东）