DEVICE FOR WELL DRILLING Russian patent published in 1994 - IPC

FIELD: well drilling. SUBSTANCE: device includes downhole motor 1 with rotor 2, stator 3 and axial bearing 4. Connected to rotor 2 is core diamond drill bit 6. Arranged inside hollow of diamond bit is roller cutter drill bit 8. Diamond bit protrudes below roller cutter drill bit. The latter is connected to rod 9 provided in axial hole 10 of shaft 11 of downhole motor 1. Rod 9 has splines 12 contacting splines 13 of carrier 14 attached to stator 3 of downhole motor 1. Rod 9 has stop shoulder 15 under carrier 14. Limiter 16 is screwed from atop into rod 9. Roller cutter drill bit may be of core type with core receiver 17 above it. EFFECT: higher efficiency. 4 cl, 2 dwg