Spiral drill collar are a kind of petroleum drilling tool series of our company. This kind of drill collar is capable of preventing differential pressure detention of tools during drilling. Spiral grooves will enable the mud to flow freely around the drill collar to use balance pressure to prevent the formation of obstruction so as to effectively prevent differential pressure jamming. The contact area against the wall of the well can be cut so as to effectively reduce the possibility of forming differential pressure obstruction.  
Spiral grooves will enable the mud to flow freely around the drill collar to use balance pressure to prevent the formation of obstruction so as to effectively prevent differential pressure jamming. The contact area against the wall of the well can be cut so as to effectively reduce the possibility of forming differential pressure obstruction.  
The extensive use of spiral drill collar is based on its characteristics. This special drill collar is able to reduce the contact area between the well wall and the pipe so as to avoid "rock-drilling jamming"of the drill string.  
The weight of spiral drill collar is 4-6% less than that of the round drill collar.