Research on the Mechanism of In-Plane Vibration on Friction Reduction.

Area of Science:

• Mechanical Engineering
• Tribology
• Petroleum Engineering

Background:

• Drilling operations face significant friction between the drill-string and borehole wall.
• Accurate prediction of friction is crucial for optimizing drilling efficiency and equipment longevity.

Purpose of the Study:

• To develop a modified model for predicting drill-string and borehole wall friction under in-plane vibrations.
• To investigate the mechanisms and influencing factors of friction reduction during vibration.

Main Methods:

• Development of a modified predictive model for friction force.
• Analysis of friction reduction mechanisms including friction force direction change and surface asperity deformation.
• Identification of key influencing factors: normal load, surface topography, vibration direction, velocity ratio, and interfacial shear factor.

Main Results:

• In-plane vibration significantly decreases the frictional coefficient in the sliding direction.
• Friction reduction is attributed to altered friction force direction, elastic deformation of asperities, and changes in the frictional coefficient.
• Key factors influencing friction force include normal load, surface topography, vibration direction, velocity ratio, and interfacial shear factor.

Conclusions:

• The modified model enhances prediction accuracy for frictional coefficients under vibrating conditions, particularly at lower velocity ratios.
• Vibrational friction reduction technology provides a theoretical basis for reducing drill-string forces.
• Results offer valuable insights for determining frictional coefficients in petroleum drilling, supporting digitized and intelligent drilling processes.