FIELD: mining.
SUBSTANCE: drilling bit includes an internal cavity interconnected through fluid medium to a drill string, many cutters and the first cutting surface out of a set of cutting surfaces; with that, the set of cutting surfaces is arranged on the external part of the drilling bit; the set of cutting surfaces has a lot of holes interconnected through fluid medium to the internal part. The set of cutting surfaces are equally spaced in a circumferential direction of the drilling bit; the set of holes provides fluid medium outlet from the internal cavity of the drilling bit. The set of holes includes at least one hole having a flow passage that is larger than other holes for creation of unbalanced lateral force; the drilling bit is made so that fluid medium is continuously supplied from the set of holes to achieve stability and reduction of vibration of the drilling bit. The drilling unit includes a drill string, a grief stem connected to the drill string and the above drilling bit. A drilling method of a curved well shaft in an underground formation includes a unit on the drill string of the above drilling bit.
EFFECT: achieving stability and reducing vibrations of a drilling bit.
8 cl, 5 dwg
