Design of coiled tubing torque reducing device

Abstract

During the operation of coiled tubing drilling, the power motor will produce reactive torque when it works, which will affect the drilling process. A torque reducing device is designed to counteract the torque by injecting drilling fluid. The device is designed as a short section, connected with cardan shaft and drive shaft, the nozzle of which can be automatically adjusted according to the pump pressure. The flow model of the device is established by SolidWorks software, and then leaded in FLUENT software for simulation. The standard k-epsilon model is used to simulate the operating conditions of 5 nozzle diameters and 2 outlet diameters respectively, and the parameters such as pressure drop, torque and flow rate are obtained. The designed torque reducing device can offset about 30% of the torque generated by the screw drill, and the reactive force of single jet is about 152N. If the jet direction is perpendicular to the axis, it can produce the drilling pressure about 3.4kN. If the direction of the nozzle is aligned with the axis, the effect of pressurization and torsion reduction can be produced simultaneously.