NEW, API SPEC 7, OD 7", ID 2-13/16", L=31FT, CON: NC50(4-1/2IF)
Spiral drill collars utilize spiral grooves to make mud circulate freely around the drill collar to equalize pressure and prevent a seal from forming. It reduces the occurrence of differential pressure sticking.
Spiral drill collars are widely used because of their low maintenance features. The special grooves decrease contact between the well side and the pipe. It lesds to the decrease of the "tack" of the pipe and to turning of the drill pipe string. The weight of round drill collars will be reduced approximately 4-6% by spiral conversion.