Mechanics Model of Driving Wheel of Wheel Tractor Based on Furrow Effect and Adhesion Effect and a Novel Design Method of Driving Wheel with Large Traction Force

In the development of horizontal wells, it is necessary to use tractors to transport logging tools. However, the current wheel tractors have relatively small traction force. To solve this problem, the wheel tractor with a novel design method of driving wheel was designed. Considering the adhesion effect and the furrow effect at the same time, the mechanical model between the driving wheel and the casing was established. Based on this, the factors affecting the friction coefficient between the casing and the driving wheel were obtained. The simulation model between the casing and the driving wheel was established. The boundary conditions and loads were set. According to numerical simulation analysis, it is found that the optimal parameters are the addendum angle of 105°, the tooth inclination angle of 120°, the bottom length of 4 mm and the embedded depth of 0.2 mm. The optimal coefficient friction between the driving wheel and the casing is 1.0476. According to the optimal parameters of the teeth of the driving wheel, a new type of driving wheel was designed. The experiment was carried out in a wheel tractor prototype. According to the unit prototype experiment, the crawling speed of the wheel tractor is 640 m/h and the maximum traction force of a single section can reach 1450 N. This verifies that this design method can indeed provide greater traction for the wheel tractor. This paper lays a theoretical foundation for wheel tractors to design the driving wheel. This is of great significance to improve the efficiency of downhole operations such as plug drilling and promote the development of long horizontal wells.