THREE-CUTTER DRILL BIT FOR HORIZONTAL WELLS AND THOSE IN HARD ROCK Russian patent published in 2016 - IPC E21B10/08 E21B10/20 

FIELD: mining.

SUBSTANCE: claimed drill bit comprises three legs and cutters fitted at lower ends thereof. Note here that upper parts of three legs are connected to make the drill bit body. Bosses of flushing nozzles are arranged between the legs on said body, flushing nozzle being fitted in the bores of said bosses. The upper rear sides of the legs back are provided with gaging teeth to create the gaging surface at the legs upper parts. Front side of the legs a linear surface and is deflected backward at α equal to 20°~40°, while β makes 3°~10°. Said surface composed of a straight line extending continuously in axis parallel with said straight line (without change in direction. It is flat or bent surface, its projection is a curve long generating line referred to as the straight line. Said front side can be composed by consecutive revolution of the plane or bent surface at the angles α and β about horizontal axis X and lengthwise axis Z of drill bit body in initial azimuth, and by sequential shift. Note here that said axes X and Z intersect at point O. When front side of the legs is flat, its initial azimuth is located on the plane XOZ composed by axes X and Z. When said front side is a curved surface with projection being a curve along the generating line, its initial azimuth is formed as the azimuth wherein the generating line is parallel with axis Z while axis X crosses two extreme points of the curve.

EFFECT: higher efficiency of drilling and drill bit.

14 cl, 7 dwg