| 摘要 |
Provided is a drill bit assembly for earth boring, the drill bit assembly comprising a drill bit having a front bit end and a rear bit end, the front bit end having a plurality of cutting elements at a forward face of the drill bit, and a first fluid return passage extending through the drill bit from the front bit end to the rear bit end; a bit sub disposed about rear bit end and coupled to the rear bit end, the bit sub comprising a body with a front sub end, a rear sub end, and a bore disposed at the front sub end sized and shaped to receive the rear bit end of the drill bit, the rear sub end adapted to connect to an adjacent downhole component; characterized in that the bit sub comprises a plurality of legs extending from the front sub end toward the front bit end between pairs of cutting elements; and a second fluid return passage connecting the first fluid return passage to the rear sub end. |
