AUGER DRILL ROD Russian patent published in 2008 - IPC E21B17/22 

FIELD: well drilling, particularly auger drill rods.

SUBSTANCE: auger drill rod comprises hollow pipe, helical spiral and rotary centering members installed on non-working helical spiral surface by means of pins and transversal to plane thereof. The centering members are made as conical discs with reinforced working surfaces and are adapted to cooperate with well wall. Angle of cone generator of each conical disc is equal to helical line inclination angle. Conical discs have smooth reinforced working surface. Conical discs are connected with pins through eccentric bushes, which may rotate through angle providing conical disc pull under helical spiral. Projection of conical disc generator onto helical line with maximal wear along diameter thereof is tangent to end surface thereof.

EFFECT: possibility to maintain well diameter, increased well wall strength, elimination of drill rod jamming during wet ground drilling.

2 cl, 5 dwg