| 摘要 |
Maximum rate of drill bit penetration in high speed coring is achieved by precise control of bit weight and bit speed. The automatic drilling system (10) of this invention makes it possible to quickly reach and maintain this optimum combination or ''sweetpoint'' each time the core bit is started. The required speed and weight is input into the system by the operator. A controller electronically senses the bit weight and provides instantaneous feedback to a hydraulically driven drawworks which is capable of maintaining a precise weight on the bit throughout varying penetration modes. The drilling system uses a combination of equipment that includes a hydraulic system for the control of the drawworks (28); a solid-state strain gauge load cell apparatus (22) built into the swivel assembly for continuously weighing the drill string; an electronic load control circuitry for determining the bit weight, drill string weight, and for maintaining the bit weight control; and, a top drive system (20) for high speed rotation of the string. |
