A Super Vibration Drag Reduction System Based on Drilling Robot

Abstract

Summary For directional or horizontal wells, friction between the drillstring and the borehole wall has become a significant factor in reducing the rate of penetration, leading to a decrease in weight on bit (WOB) and inefficient rock breaking. Generally, a larger amplitude yields a better oscillation effect. Conventional hydraulic oscillators rely on their inherent inertia to produce oscillating loads. However, the mass of the oscillating load provided by hydraulic oscillators is relatively small compared with the entire pipe string, resulting in limited oscillation amplitude that fails to effectively reduce friction and drag. To enhance the vibration effect and strength of the pipe string, in this article we propose the development of a novel hydraulic oscillation device that utilizes drilling robots for support. The relevant structure of the drilling robot has been designed, and a simulation wellbore experiment platform, based on the drilling robot, has been constructed. The simulation wellbore experiment based on different supporting conditions was completed. Through analysis of the collected experimental data, it has been observed that the axial and radial vibrations generated by the drilling robot are influenced by its supporting condition. The average acceleration amplitude and frequency of axial vibration without support are measured to be 0.37 m/s² and 8.2 Hz, respectively. In contrast, with supporting conditions, the average axial vibration acceleration amplitude increases to 0.63 m/s², and the frequency reaches 12.8 Hz. Consequently, the axial vibration intensity of the drilling robot is significantly higher when the drilling robot is supported. The average acceleration amplitude and frequency of radial vibration without support are 0.83 m/s² and 20.4 Hz, respectively. However, with supporting conditions, the average radial vibration acceleration amplitude drops to 0.43 m/s², and the frequency decreases to 12.2 Hz. The average axial vibration displacement amplitude of the supported drilling robot measures 50.2 mm, which is much greater than that of a typical hydraulic oscillator. Moreover, the WOB of the drilling robot with support is considerably higher compared with the unsupported drilling robot. By employing supporting conditions, the drilling robot can improve the transmission efficiency of drilling pressure and minimize the damage caused by radial vibration to downhole tools.