Application Research On Swirling Water Jet Self-propelled Drilling Technology For Gas Drainage

Swirling water jet is a high-pressure water through the nozzle from the orientated impeller inside the drill which is a diffusive jet with the three-dimension speed moving along the spiral line and has a particular structural properties and high rock-breaking efficiency. This dissertation intends to use swirling water jet drill in ultra-short radius horizontal drilling technology for coal seam methane drainage by drilling horizontal wells in coal seam which provides a new method for the low penetration coal seam methane drainage in China.This dissertation describes the generation mechanism of the swirling water jet, analyzes the structural characteristics of its speed and pressure and has a detailed analysis of its unique rock-breaking mechanism different from the ordinary water jet. According to the structural properties of swirling water jet, this dissertation designs the self-propelled bit of swirling water jet for the ultra-short radius horizontal drilling system and has a theoretical analysis of the size of swirling water jet drilling diameter, the propulsion and drilling depth, the impact of drilling speed in coal seam on drilling diameter and the influence of the size of propulsion on the drilling depth. Finally it uses CFD software Fluent on the simulation of swirling water jet, further analyzes the impact of drill structural parameters on the structural characteristics of swirling water jet and optimizes the drill structure.