Resumen de Trajectory design based on frictional resistance of deflector in a hydraulic radial drilling system
Biwei Fu, Zhiyuan Guo, Jia Yan, Si Zhang
The trajectory design is a key factor affecting the frictional resistance of the deflector, which is crucial for the drilling ability of the hydraulic radial drilling system. In this research, the trajectory design model and geometric constraints model of a deflector are established by analyzing the geometric relationship of the deflector and considering the geometric constraints of the casing. According to the actual contact form between the high-pressure hose and the deflector, the theoretical model of frictional resistance is built based on segmental rigidization and micro-element methods. The theoretical model is verified by the deflector friction experiment. The results demonstrate a good agreement between the experimental results of friction resistance of different sizes of high-pressure hoses and the theoretical results, with an error of less than 7%. The influence of critical parameters of deflector trajectory on the friction resistance is studied by coupling the geometric constraints model and the frictional resistance theoretical model of the deflector. The findings show that the deflector’s frictional resistance increases with the inclination angle β of the inclined-straight section and decreases with the increase in the radius R of the bending segment, the inclination angle ω of the straightening segment, and the channel radius of r deflector. A new trajectory parameters of the deflector are presented by taking a five-inch casing as an example, they are β = 9°, R = 92 mm, ω = 108°, r = 17 mm. The research results provide a theoretical rationale for designing a low-frictional resistance deflector.
