Spiral drill collar can be prevented Downhole drilling tools during drilling differential pressure block, spiral grooves may allow mud flow freely around the drill collar to balance the pressure to prevent the formation of block, thereby effectively preventing differential sticking occurred. You can reduce the contact area with the drilling shaft, and thus the possibility of blocking the differential pressure can be effectively reduced. The reason why the spiral drill collars are widely used because of its own characteristics of the decision, this particular spiral drill collars to reduce the contact area between the wall and the tube, thereby avoiding "sticking" phenomenon of the drill string.