DEVICE FOR WELL DRILLING Russian patent published in 1994 - IPC

FIELD: well drilling. SUBSTANCE: downhole hammer has adapter for connecting drill pipe string, body 2 connected with adapter 1. Striker 4 with axial channel 5 is accommodate in hollow 3 of body 2. Striker 4 is installed for vertical motion over guides 6. Attached to lower part of body 2 is unit for axial disconnection of pipe string in form of carrier 7 and spindle 8 with axial channel 9 and with anvil 10 in upper part. Carrier 7 and spindle 8 are conjugated by polyhedral surfaces. Screwed on lower end of spindle 8 is bottom collar adapter 12 for connecting drilling bit. Channel 9 in spindle 8 is coaxial with axial channel 5 in striker. Channel 5 has cross-section same over the entire height of striker and equal to that of channel 9 of spindle 8. In this case, striker and spindle are installed so that during operation of striker channels 9 and 5 are continuously communicated with each other. Hammer is connected with pipe string and lowered to bottom hole and drilling mud is supplied to drill pipe string. Static load on bit is imparted by part of mass of bottom-hole drill pipe string assembly and mass of striker 4. Static load is transmitted through adapter 1, body 2, carrier 7 and its end faces (bottom) and bottom collar adapter 12 (top). During rotation of hammer, the drill bit resting on bottom hole executes vertical motions and rolling over bottom hole. Vertical motions are transmitted to striker 4 through carrier 7, body 2 and adapter 1. Said units, after reaching top point, freely drop under gravity and deliver blows against bit to make roller bit teeth intrude into rock. Simultaneously with mechanical blows striker 4 and body 2 together with carrier excite hydraulic pulse while moving downward. Hydraulic pulse is directed towards bottom hole and fluid flow is formed in same direction. EFFECT: simple design, higher reliability and longer service life. 3 dwg