GB1467519A - Earth drilling a-paratus - Google Patents

Abstract

1467519 Earth drilling SMITH INTERNATIONAL INC 12 March 1974 [23 March 1973] 10931/74 Heading E1F A mobile drilling rig includes a selfpropelled wheeled vehicle carrying a mast 14 14 pivotable between a horizontal transport position and an inclined or upright operative position, a carriage 26 being movable along the mast, e.g. by transmission chains 28 connected to hydraulic rams, the carriage supporting a drill head 34 which is hinged at 36 and movable by ram 42 between one position in which it is aligned with the drilling axis and another position in which it is aligned with a slotted pipe holder 52. At the top of the mast is a boom 58 with sheaves 60, 64 over which a hoisting cable 62 is trained, the cable being used to transfer drill pipes between rack 46 and the pipe holder, the cable suitably being fitted with a pipe handling tool (Fig. 7) including a rod 74 with a pin 80, intended for rereception in one end of a pipe, and a cable 76 connected to a head 84 having a longer pin 82 intended for reception in the other end of the pipe. In use, the pin 82 is inserted in the trailing end of a pipe in the rack 46 and the tool is moved rearwards to insert the pin 80 in the leading end of the pipe which is then held captive by the pins while the cable 62 is used to move the pipe out of the rack to a vertical position in which it can be introduced into the holder 52, the rod 74 aligning with an axial slot in the holder, and the pin 80 being disengaged from the pipe by lowering the tool relative to the pipe, the tool then being movable vertically to withdraw pin 82 from the pipe and thus being freed for return to the rack to pick up the next pipe for transfer to the holder. A pipe standing in the holder is picked up by the drill head 34, while the latter is aligned with the holder, the drill head then being returned to alignment with the drilling axis so that the new pipe can be added to the drill string. To remove a drill string from the borehole, the drill head is moved to its position aligned with the holder and a hoisting block 40 is lowered through the space in the carriage 26 normally occupied by the drill head, the block being used to pickup the drill string and to transfer each successive pipe back to the rack, the pipes being separated from the string with the aid of a break-out tong (72). The boom 58 may be telescopic so that cable 62 can be placed adjacent the drilling axis and used to run tools and casing into the borehole.