It is used to manufacture the finished drill pipe and drilling tool. Its main functions are as follows: first, to transmit torque; second, the upper drill tool bears part of the weight of the drill string itself, and the lower drill tool causes the pressure of breaking the bottom hole rock to the drill bit; third, to transport the well washing fluid, namely drilling mud Through the high-pressure mud pump on the ground, the mud is pumped into the tap to enter the inner hole of the drill string, flow into the bottom of the well, wash the cuttings, cool the drill bit, and carry the cuttings back to the surface through the annular space between the outer surface of the drill string and the wellbore, so that the bottom of the well is deepened continuously until it reaches the target layer.
